The broad-spectrum anti-DNA virus agent cidofovir inhibits lung metastasis of virus-independent, FGF2-driven tumors

The FDA-approved anti-DNA virus agent cidofovir (CDV) is being evaluated in phase II/III clinical trials for the treatment of human papillomavirus (HPV)-associated tumors. However, previous observations had shown that CDV also inhibits the growth of vascular tumors induced by fibroblast growth factor-2 (FGF2)-transformed FGF2-T-MAE cells. Here, we demonstrate that CDV inhibits metastasis induced by FGF2-driven, virus-independent tumor cells. Pre-treatment of luciferase-expressing FGF2-T-MAE cells with CDV reduced single cell survival and anchorage-independent growth in vitro and lung metastasis formation upon intravenous inoculation into SCID mice. This occurred in the absence of any effect on homing of FGF2-T-MAE cells to the lungs and on the growth of subconfluent cell cultures or subcutaneous tumors in mice. Accordingly, CDV protected against lung metastasis when given systemically after tumor cell injection. Lung metastases in CDV-treated mice showed reduced Ki67 expression and increased nuclear accumulation of p53, indicating that CDV inhibits metastasis by affecting single cell survival properties. The anti-metastatic potential of CDV was confirmed on B16-F10 melanoma cells, both in zebrafish embryos and mice. These findings suggest that CDV may have therapeutic potential as an anti-metastatic agent and warrants further study to select those tumor types that are most likely to benefit from CDV therapy.

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title: Acyclic nucleoside phosphonates: a key class of antiviral drugs
abstract: Almost 20 years after the broad antiviral activity spectrum of the first acyclic nucleoside phosphonates was described, several of these compounds have become important therapies for DNA virus and retrovirus infections. Here, we review the discovery and development of acyclic nucleoside phosphonates, focusing on cidofovir and its potential in the treatment of various herpes-, papilloma-, polyoma-, adeno- and pox-virus infections, adefovir for the treatment of hepatitis B and tenofovir for the treatment of AIDS and the prevention of HIV infections.

title: The antiviral agent cidofovir [(S)-1-(3-hydroxy-2-phosphonyl-methoxypropyl)cytosine] has pronounced activity against nasopharyngeal carcinoma grown in nude mice.
abstract: The effect of the antiviral agent (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl) cytosine (cidofovir) on the EBV-associated tumor nasopharyngeal carcinoma (NPC) was evaluated in NPC xenografts in athymic mice. Intratumoral injection arrested tumor growth within 1 week, and by 4 weeks, tumors regressed to 8-75% (39 +/- 33%) of the original size, whereas control tumors injected with PBS grew to 282 +/- 25% of the original size. Ganciclovir slowed but did not arrest or cause regression of tumor growth. A striking antitumor effect was also produced by systemic administration; at 4 weeks, tumors were 79 +/- 49% of the original size, compared with 635 +/- 91% for the controls. Widespread apoptosis was detected after treatment for 2-6 days in C15 as well as two other NPC xenografts, C17 and C18; the latter NPCs have mutations in the p53 gene. These data indicate that cidofovir induces rapid cell death through apoptosis in EBV-transformed epithelial cells.

title: Inhibition of fibroblast growth factor-2-induced vascular tumor formation by the acyclic nucleoside phosphonate cidofovir.
abstract: Cidofovir [(S)-HPMPC; (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine] is an antiviral drug that has been approved for the treatment of cytomegalovirus retinitis in AIDS patients. Cidofovir also possesses potent inhibitory activity against various human papillomavirus-induced tumors in animal models and patients. In addition, cidofovir inhibits the development of murine polyomavirus-induced hemangiomas in rats by an as-yet-uncharacterized, antivirus-independent mechanism. Here we report the inhibitory effect of cidofovir on the development of virus-independent vascular tumors originated by basic fibroblast growth factor (FGF2)-overexpressing endothelial cells (FGF2-T-MAE cells). In vitro, cidofovir was cytostatic to FGF2-T-MAE cells at a 50% cytostatic concentration of 6.7 microg/ml. Cidofovir concentrations >25 microg/ml resulted in cytotoxicity because of induction of apoptosis. Cidofovir did not affect FGF2-T-MAE cell sprouting in three-dimensional fibrin gel and morphogenesis on Matrigel at noncytotoxic concentrations. In vivo, cidofovir (100 microg/egg) completely suppressed hemangioma formation on the chick chorioallantoic membrane (CAM) induced by intra-allantoic injection of FGF2-T-MAE cells, without affecting the formation of normal CAM vessels. Accordingly, cidofovir applied locally at 200 microg/disc, reduced neovascularization on the CAM by only 35%. Intratumoral or systemic administration of cidofovir caused a significant inhibition of the growth of s.c., i.p., or intracerebral FGF2-T-MAE xenografts in nude mice and severe combined immunodeficient mice. Drug-induced apoptosis was observed in FGF2-T-MAE tumors as soon as 2 days after the beginning of treatment. In conclusion, cidofovir appears to inhibit the growth of endothelium-derived tumors via induction of apoptosis without exerting a direct antiangiogenic activity.

title: Potent inhibition of hemangiosarcoma development in mice by cidofovir
abstract: The acyclic nucleoside phosphonate analogue cidofovir is a broad‐spectrum anti‐DNA virus agent, which also possesses potent inhibitory activity against various tumors associated with papillomaviruses in animal models and patients. Moreover, we recently described the potent inhibition of polyomavirus (PyV)‐induced hemangioma formation in rats by cidofovir. This activity could not be explained by an antiviral mechanism. We have now evaluated the effect of cidofovir on the growth of hemangiosarcomas originating from PyV‐transformed (PV/2b/35) cells, which do not produce polyomavirus. In vitro, cidofovir proved to be cytostatic for PV/2b/35 cells at a 50% cytostatic concentration (CC50) of 2.3 μg/ml. At cidofovir concentrations ≥20 μg/ml, cytotoxicity due to induction of apoptosis was observed. In vivo, intratumoral therapy with cidofovir, at 100 mg/kg 3 times a week, completely inhibited the development and even caused regression of established PV/2b/35 hemangiosarcomas in nude mice. Five days after the start of treatment, few proliferating cells were noted in the cidofovir‐treated tumors, whereas control tumors were characterized by high expression of proliferating cell nuclear antigen (PCNA). Moreover, cidofovir induced apoptosis in the hemangiosarcomas, as evidenced by Tunel (terminal deoxynucleotidyl transferase‐mediated dUTP nick end labeling) staining. Also after intraperitoneal administration, cidofovir afforded a prominent protection against the growth of intraperitoneally or intracerebrally inoculated hemangiosarcoma cells in SCID mice. In conclusion, cidofovir possesses a direct antitumor activity, which is mediated by induction of tumor cell apoptosis. Cidofovir should be further explored for its potential in the treatment of fast‐growing vascular tumors, like hemangiomas and hemangiosarcomas.

title: Reduced tumorigenicity and pathogenicity of cervical carcinoma SiHa cells selected for resistance to cidofovir
abstract: BackgroundInsights into the mechanisms associated with chemotherapy-resistance are important for implementation of therapeutic strategies and for unraveling the mode of action of chemotherapeutics. Although cidofovir (CDV) has proven efficacious in the treatment of human papillomavirus (HPV)-induced proliferation, no studies concerning the development of resistance to CDV in HPV-positive tumor cells have been performed yet.MethodsFrom the cervical carcinoma SiHa cells (SiHaparental), which are HPV-16 positive, cidofovir-resistant cells (SiHaCDV) were selected, and differential gene expression profiles were analyzed by means of microarrays. We examined in vitro phenotyping of resistant cells compared to parental cells as well as tumorigenicity and pathogenicity in a mouse-xenograft model.ResultsSiHaCDV had a resistant phenotype and a reduced growth both in vitro and in vivo. A markedly diminished inflammatory response (as measured by production of host- and tumor-derived cytokines and number of neutrophils and macrophages in spleen) was induced by SiHaCDV than by SiHaparental in the xenograft model. Gene expression profiling identified several genes with differential expression upon acquisition of CDV-resistance and pointed to a diminished induction of inflammatory response in SiHaCDV compared to SiHaparental.ConclusionsOur results indicate that acquisition of resistance to cidofovir in SiHa cells is linked to reduced pathogenicity. The present study contributes to our understanding on the antiproliferative effects of CDV and on the mechanisms involved, the inflammatory response playing a central role.

title: Effects of cidofovir on human papillomavirus-positive cervical cancer cells xenografts in nude mice.
abstract: Cidofovir (CDV) is an acyclic nucleoside phosphonate analog that shows broad spectrum anti-DNA virus activity. In this study, we have investigated the influence of cidofovir on the tumor xenografts derived from HeLa and SiHa cells on nude mice. The HeLa/SiHa xenografts in nude mice were established by inoculating cells subcutaneously. Administration of cidofovir by intratumoral injection led to significant tumor reduction. Enhanced protein levels of p53 and p-pRb within the tumor samples were observed. Immunohistology analysis of the tumor sections indicated decreased PCNA index and increased apoptosis index. Our study gives more evidence and explanation on in vivo inhibition effect of cidofovir on HPV genome-positive cervical carcinoma cell line xenografts.

title: Antiviral agent Cidofovir restores p53 function and enhances the radiosensitivity in HPV-associated cancers
abstract: High-risk human papillomaviruses (HPVs) have been associated to the development of cervical and some other human cancers. Most of them express E6 and E7 oncoproteins, able to bind to p53 and retinoblastoma (pRb) tumor suppressor proteins respectively and neutralize their function. Restoration of these pathways by blocking E6 and E7 expression would provide a selective therapeutic effect. Here, we show that a clinically approved antiviral agent Cidofovir reduced E6 and E7 expression in cervical carcinoma Me180 and head and neck squamous cell carcinoma HEP2 cells at the transcriptional level. Cidofovir induced the accumulation of active p53 and pRb associated to induction of cyclin dependent kinase inhibitor p21WAF1/CIP1 in Me180 and HEP2 cells. p53 induction was also shown in Hela HPV-positive cervical carcinoma cell line. In addition, S phase cell cycle accumulation with concomitant decrease of cyclin A expression were associated to the antiproliferative activity of Cidofovir in HPV-treated cells. Combining Cidofovir to irradiation both in vivo and in nude mice xenografts resulted in a marked radiosensitization in HPV-positive cells, which was not observed in virus negative cells. This study provides the basis for a new anticancer strategy to enhance the antitumor effect of ionizing radiation in HPV-related cancers, without increase deleterious effects.

title: Cidofovir Administered with Radiation Displays an Antiangiogenic Effect Mediated by E6 Inhibition and Subsequent TP53-Dependent VEGF Repression in HPV18+ Cell Lines
abstract: Amine, A., Vozenin-Brotons, M-C., Abdulkarim, B., Violot, D., Aubel, C. and Bourhis, J. Cidofovir Administered with Radiation Displays an Antiangiogenic Effect Mediated by E6 Inhibition and Subsequent TP53-Dependent VEGF Repression in HPV18+ Cell Lines.  (2006). Therapeutic administration of the antiviral agent cidofovir with radiation markedly enhanced the antitumor effect of ionizing radiation in cells of two HPV18+ human cervical carcinoma cell lines. Although this potent radiosensitizing effect was associated with repression of the viral oncoproteins E6/ E7 and restoration of TP53 as shown previously, additional mechanisms may be involved. In the present study, we investigated the antiangiogenic effect of the combination of cidofovir and radiation in cells of two HPV18+ cervical cancer cell lines, HeLa and ME180, and assessed the molecular mechanisms associated with the antiangiogenic effect observed. Cells were exposed to cidofovir (10 μg/ml) and irradiated (1– 9 Gy). The angiogenic response was studied in vitro by a matrigel invasion assay. Modulations of E6, TP53 and VEGF mRNA and protein levels were studied by real-time RT-PCR, Western blot analysis and ELISA, respectively. Then a double RNA interference approach was used to analyze the connection between E6/TP53 and VEGF. The combination of cidofovir and radiation had a potent antiangiogenic effect. It induced E6 inhibition, restoration of TP53, and reduction of the proangiogenic phenotype of HPV18+ cells associated with VEGF inhibition. A siRNA strategy showed an anti-VEGF action of the combination mediated directly by E6 inhibition and TP53 restoration, since E6 siRNA inhibited VEGF whereas co-transfection with E6 and TP53 siRNA abrogated the anti-VEGF effect. This study showed that the combination of cidofovir with ionizing radiation has an antiangiogenic effect associated with VEGF inhibition subsequent to E6 inhibition and TP53 restoration.

title: Antiviral activity of Cidofovir on a naturally human papillomavirus-16 infected squamous cell carcinoma of the head and neck (SCCHN) cell line improves radiation sensitivity.
abstract: High risk HPV types 16 and 18 are associated with cervical cancer and squamous cell carcinoma of the head and neck (SCCHN). Cidofovir is an antiviral drug used to treat HPV-induced laryngeal papillomatosis and other viral infections, with initial reports suggesting activity in cervical carcinoma cells. We investigated the effects of Cidofovir on a naturally HPV-16-transformed SCCHN cell line (UPCI:SCC090), in comparison with a cervical carcinoma cell line (CasKi) of similar viral characteristics, to evaluate its therapeutic potential. HPV-16 gene transcription was only marginally reduced, and the antiviral and p53 restorative effects were modest in SCC90 cells. However, combination with irradiation enhanced the effects of Cidofovir treatment on these cells. Several days of treatment were required for this effect, which may limit its clinical applicability. Future therapies for HPV-associated tumors may include intralesional antiviral therapy in combination with radiation therapy, but optimization for clinical utility is needed.

title: Treatment of locally recurrent epstein–barr virus‐associated nasopharyngeal carcinoma using the anti‐viral agent cidofovir
abstract: Nasopharyngeal carcinoma (NPC) is an Epstein–Barr virus (EBV) associated malignant tumor. Recently, cidofovir, an anti‐viral drug which is an acyclic nucleoside analogue, has been reported to have an anti‐tumor potential. Two patients with NPC, who had previously received multi‐round therapy, were treated with cidofovir. Cidofovir was topically injected in and around the tumor once every 3 weeks (originally 75 mg/ml sulution, diluted to 15 mg/ml just before injection, 37.5 mg of cidofovir at a time). Tumor growth was suppressed for several months around the injection site in each patient. EBV‐encoded RNAs in situ hybridization revealed the reduction of the tumor cell population; however, the EBER expression was still maintained in the NPC tumor cells. Although the anti‐tumor mechanism remains unclear, these results suggest that cidofovir is actually an effective and safe agent for the treatment of NPC.  2008.

title: Safety and efficacy of topical cidofovir to treat high-grade perianal and vulvar intraepithelial neoplasia in HIV-positive men and women
abstract: To evaluate the safety and efficacy of topical cidofovir for treatment of high-grade squamous perianal intraepithelial neoplasia (PAIN) and vulvar intraepithelial neoplasia (VIN) lesions in HIV-positive individuals. Phase IIa prospective multicenter trial conducted at eight clinical sites through the AIDS Malignancy Consortium. HIV-positive patients with biopsy-proven high-grade PAIN that was at least 3 cm2 were enrolled. PAIN biopsy specimens were assessed for human papillomavirus (HPV) using PCR and type-specific HPV probing. Participants applied 1% topical cidofovir to PAIN and VIN (if present) for six 2-week cycles. Results were designated as complete response (CR), partial response (PR) (>50% reduction in size), stable disease, or progressive disease (PD). Twenty-four men and nine women (eight with high-grade VIN as well) were enrolled. Mean age was 44 years and mean CD4+ cell count was 412 cells/&mgr;l. HPV DNA (most commonly HPV16) was detected in all pretreatment study specimens. Twenty six (79%) participants completed treatment per protocol: CR, five (15%); PR, 12 (36%), stable disease, seven (21%); PD, two (6%) (one with a superficially invasive cancer and one with new area of high-grade PAIN). Treatment was well tolerated with most common adverse events being mild to moderate affecting lesional skin: pain/burning/irritation (25 patients) and ulceration (13 patients). Topical cidofovir had 51% efficacy in the short-term treatment of high-grade PAIN and VIN with acceptable toxicity in HIV-positive individuals. Randomized control studies with more prolonged treatment courses and longer follow-up to assess the durability of the response are needed.

title: Activity, safety, and feasibility of cidofovir and imiquimod for treatment of vulval intraepithelial neoplasia (RT³VIN): a multicentre, open-label, randomised, phase 2 trial.
abstract: Vulval intraepithelial neoplasia is a skin disorder affecting the vulva that, if left untreated, can become cancerous. Currently, the standard treatment for patients with vulval intraepithelial neoplasia is surgery, but this approach does not guarantee cure and can be disfiguring, causing physical and psychological problems, particularly in women of reproductive age. We aimed to assess the activity, safety, and feasibility of two topical treatments--cidofovir and imiquimod--as an alternative to surgery in female patients with vulval intraepithelial neoplasia.



We recruited female patients (age 16 years or older) from 32 centres to an open-label, randomised, phase 2 trial. Eligibility criteria were biopsy-proven vulval intraepithelial neoplasia grade 3 and at least one lesion that could be measured accurately. We randomly allocated patients to topical treatment with either 1% cidofovir (supplied as a gel in a 10 g tube, to last 6 weeks) or 5% imiquimod (one 250 mg sachet for every application), to be self-applied three times a week for a maximum of 24 weeks.  The primary endpoint was a histologically confirmed complete response at the post-treatment assessment visit 6 weeks after the end of treatment (a maximum of 30 weeks after treatment started). Analysis of the primary endpoint was by intention to treat. Secondary outcomes were toxic effects (to assess safety) and adherence to treatment (to assess feasibility). We present results after all patients had reached the primary endpoint assessment point at 6 weeks; 2-year follow-up of complete responders continues. 
Between Oct 21, 2009, and Jan 11, 2013, 180 participants were enrolled to the study; 89 patients were randomly allocated cidofovir and 91 were assigned imiquimod. At the post-treatment assessment visit, a complete response had been achieved by 41 (46%; 90% CI 37·0-55·3) patients allocated cidofovir and by 42 (46%; 37·2-55·3) patients assigned imiquimod. After 6 weeks of treatment, 156 (87%) patients (78 in each group) had adhered to the treatment regimen. Five patients in the cidofovir group and seven in the imiquimod group either withdrew or were lost to follow-up before the first 6-week safety assessment. Adverse events of grade 3 or higher were reported in 31 (37%) of 84 patients allocated cidofovir and 39 (46%) of 84 patients assigned imiquimod; the most frequent grade 3 and 4 events were pain in the vulva, pruritus, fatigue, and headache.



Cidofovir and imiquimod were active, safe, and feasible for treatment of vulval intraepithelial neoplasia and warrant further investigation in a phase 3 setting. Both drugs are effective alternatives to surgery for female patients with vulval intraepithelial neoplasia after exclusion of occult invasive disease.

title: Systematic review of intralesional cidofovir dosing regimens in the treatment of recurrent respiratory papillomatosis.
abstract: Surgical management of recurrent respiratory papillomatosis (RRP) usually involves resection via microlaryngoscopy. Intralesional injection of cidofovir has been shown to be an effective adjuvant treatment, but remains unlicensed. United Kingdom General Medical Council guidelines recommend the prescribing doctor should "be satisfied that there is a sufficient evidence base and/or experience of using the medicine to demonstrate its safety and efficacy". This study reviews the published dosing regimens of intralesional cidofovir in the treatment of RRP in order to provide a precedent for those that wish to prescribe it.



A systematic review of the literature was undertaken using Medline, EMBASE and CINAHL. Articles describing the use of intralesional cidofovir for RRP were reviewed. Information regarding cidofovir concentration, volume, total dose, number of treatments, interval between treatments, overall treatment period and follow up was extracted.



Fifty-one articles were identified. Concentration of cidofovir injected ranged from 0.0001mg/ml to 37.5mg/ml, with 5 to 7.5mg/ml being the most common. The volume of cidofovir solution injection ranged from 0.1 to 20ml. The total dose per injection ranged from 0.15 to 105mg. There was wide variation in dosing regimens with different intervals between endoscopies, number of injections and total doses delivered.



Based on this published literature, the precedent for prescribing intralesional cidofovir supports a concentration of 5 to 7.5mg/ml. Volumes up to 5ml per injection are routinely used. Total dose and frequency of cidofovir administration is highly variable. The need for repeat doses of cidofovir should be judged on an individual basis.

title: Topical treatment of CIN 2+ by cidofovir: results of a phase II, double-blind, prospective, placebo-controlled study.
abstract: Randomized controlled trial evaluating a topical treatment for cervical intraepithelial neoplasia 2 and 3 (CIN 2+) using cidofovir.



Fifty-three women with a biopsy-proven CIN 2+ were randomly assigned, 6 weeks before their planned conisation, either 3 applications of 3 ml 2% cidofovir in Intrasite gel in a cervical cap or a placebo (the same volume of Intrasite alone). A cervical sample for high-risk types of human papillomaviruses (HPV) (Hybrid Capture 2 or HC2) was taken before treatment and before conisation. The cone was submitted for pathological examination, and subsequently, along with the initial biopsy, to in situ hybridization (ISH) for high-risk HPV.



Forty-eight patients were treated and followed according to the protocol, (23 cidofovir, and 25 placebo). Fourteen of the 23 cones were free of any CIN (60.8%) in the cidofovir group. Only 5 of 25 cones were free of any CIN (20%) in the placebo group (p<0.01). The difference remained significant in the ITT group (p<0.05). In the per-protocol and ITT populations, we observed more frequent viral clearance in the cidofovir group, but the difference was significant only when evaluated by ISH and not by HC2. No systemic toxicity was observed. Cervico-vaginal side effects of cidofovir were limited, and not statistically different from placebo.



The medical topical treatment with cidofovir, at this point, cannot replace conisation, but it is a promising candidate for topical chemotherapy of CIN 2+ lesions; a larger prospective randomized study is needed to confirm our results.

title: Cidofovir: A Novel Antitumor Agent for Glioblastoma
abstract: Cidofovir (CDV) is an U.S. Food and Drug Administration (FDA)-approved nucleoside antiviral agent used to treat severe human cytomegalovirus (HCMV) infection. Until now, no clear therapeutic effects of CDV have been reported outside of the setting of viral infection, including a potential role for CDV as an antineoplastic agent for the treatment of brain tumors.  We investigated the cytotoxicity of CDV against the glioblastoma cells, U87MG and primary SF7796, both in vitro and in vivo, using an intracranial xenograft model. Standard techniques for cell culturing, immunohistochemistry, Western blotting, and real-time PCR were employed. The survival of athymic mice (n = 8–10 per group) bearing glioblastoma tumors, treated with CDV alone or in combination with radiation, was analyzed by the Kaplan–Meier method and evaluated with a two-sided log-rank test.  CDV possesses potent antineoplastic activity against HCMV-infected glioblastoma cells. This activity is associated with the inhibition of HCMV gene expression and with activation of cellular apoptosis. Surprisingly, we also determined that CDV induces glioblastoma cell death in the absence of HCMV infection. CDV is incorporated into tumor cell DNA, which promotes double-stranded DNA breaks and induces apoptosis. In the setting of ionizing radiotherapy, the standard of care for glioblastoma in humans, CDV augments radiation-induced DNA damage and, further, promotes tumor cell death. Combination therapy with CDV and radiotherapy significantly extended the survival of mice bearing intracranial glioblastoma tumors.  We have identified a novel antiglioma property of the FDA-approved drug CDV, which heightens the cytotoxic effect of radiotherapy, the standard of care therapy for glioblastoma. ); 6473–83.

title: Topical 1% cidofovir for the treatment of basal cell carcinoma.
abstract: Cidofovir, a purine nucleotide analogue of deoxycytidine, is a drug effective against a wide number of DNA viruses. Recently, cidofovir has been supposed to exert antineoplastic activity, through the induction of apoptosis and the inhibition of angiogenesis. Four patients affected by basal cell carcinoma (BCC), who refused conventional surgery, were treated with a cream containing 1% cidofovir. The cream was applied every day for 10 days, then every other day for another 50 days. Histopathologic clearing was assessed with a skin biopsy performed on the previous lesional area 3 months after the end of treatment. All four patients achieved clinical healing of their lesion. Histological tumour regression was achieved in three patients. The treatment was well tolerated and the cosmetic results were excellent. No recurrences after an average 24-month follow up period were detected. The potential effectiveness of topical cidofovir for the non-surgical treatment of BCC have been shown. Nevertheless, appropriate clinical trials and prolonged follow-up periods are needed to confirm the efficacy and safety of topical cidofovir.

title: Successful treatment of squamous cell carcinoma of the lower eyelid with intralesional cidofovir
abstract: Cidofovir (HPMPC), an acyclic nucleoside phosphonate analogue, is a promising drug that acts against a wide number of DNA  In 1997, the US Federal Food and Drug Administration approved cidofovir (for intravenous use only) for the treatment of cytomegalovirus retinitis in patients with AIDS.1 Over the last few years, cidofovir in a 1–3% gel or cream vehicle has been found to be effective against unmanageable viral cutaneous lesions induced by herpes, pox, and papilloma families.2 Recent studies have explored intralesional administration of cidofovir for the treatment of HPV related tumours, such as cervical epithelial neoplasia, oesophageal carcinomas, and HSV-8 induced Kaposi’s sarcoma.3–6 We report a squamous cell carcinoma (SCC) of the eyelid which was successfully …

title: Purification from a human hepatoma cell line of a basic fibroblast growth factor-like molecule that stimulates capillary endothelial cell plasminogen activator production, DNA synthesis, and migration.
abstract: A 17,500-dalton protein which stimulates plasminogen activator production in cultured bovine capillary endothelial cells has been purified from a SK-Hep-1 human hepatoma cell lysate by using heparin affinity chromatography and fast protein-liquid ion exchange chromatography. The purified molecule stimulated plasminogen activator production in a dose-dependent manner between 0.01 and 1 ng/ml. It also stimulated collagenase synthesis, DNA synthesis, and motility in capillary endothelial cells in the same concentration range. This molecule was identified as a basic fibroblast growth factor-like molecule on the basis of its biological activity, its affinity for heparin-Sepharose, and its cross-reactivity with a polyclonal antibody raised against the human placental basic fibroblast growth factor.

title: Angiogenic factors FGF2 and PDGF-BB synergistically promote murine tumor neovascularization and metastasis.
abstract: Tumors produce multiple growth factors, but little is known about the interplay between various angiogenic factors in promoting tumor angiogenesis, growth, and metastasis. Here we show that 2 angiogenic factors frequently upregulated in tumors, PDGF-BB and FGF2, synergistically promote tumor angiogenesis and pulmonary metastasis. Simultaneous overexpression of PDGF-BB and FGF2 in murine fibrosarcomas led to the formation of high-density primitive vascular plexuses, which were poorly coated with pericytes and VSMCs. Surprisingly, overexpression of PDGF-BB alone in tumor cells resulted in dissociation of VSMCs from tumor vessels and decreased recruitment of pericytes. In the absence of FGF2, capillary ECs lacked response to PDGF-BB. However, FGF2 triggers PDGFR-alpha and -beta expression at the transcriptional level in ECs, which acquire hyperresponsiveness to PDGF-BB. Similarly, PDGF-BB-treated VSMCs become responsive to FGF2 stimulation via upregulation of FGF receptor 1 (FGFR1) promoter activity. These findings demonstrate that PDGF-BB and FGF2 reciprocally increase their EC and mural cell responses, leading to disorganized neovascularization and metastasis. Our data suggest that intervention of this non-VEGF reciprocal interaction loop for the tumor vasculature could be an important therapeutic target for the treatment of cancer and metastasis.

title: Nuclear FGF-2 facilitates cell survival in vitro and during establishment of metastases
abstract: Nuclear-targeted high molecular weight 24 kDa fibroblast growth factor 2 (FGF-2) may induce specific cell functions through intracrine mechanisms. The role of nuclear FGF-2 on the metastatic potential of carcinoma cells was examined by conditional FGF-2 expression, which demonstrated that spontaneous metastasis in nude mice is a direct consequence of its expression. The lung colonizing capacities of fluorescent nuclear FGF-2-expressing cells following intravenous injection was also investigated. All cells reaching the lung extravasated as soon as 5 min following injection with similar in vivo behavior during the first 24 h. However, after 2 days, dramatic differences were observed between the FGF-2 and parental cells: most control cells underwent apoptosis, while the FGF-2-producing cells instigated a survival program and proliferated. Therefore, sustained apoptosis in vivo prevents growth of metastatic foci, while nuclear FGF-2 induction of a survival program is responsible for growth of the lung metastases. In vitro serum deprivation assays also established that 24 kDa FGF-2 expression improves carcinoma cell survival. This study provides both in vitro and in vivo evidence that the role of the nuclear 24 kDa FGF-2 isoform in carcinoma is the promotion of cell survival, thereby defining its association with poor prognosis in some human carcinomas.

title: Inhibition of tumor angiogenesis and growth by a small-molecule multi-FGF receptor blocker with allosteric properties.
abstract: Receptor tyrosine kinases (RTK) are targets for anticancer drug development. To date, only RTK inhibitors that block orthosteric binding of ligands and substrates have been developed. Here, we report the pharmacologic characterization of the chemical SSR128129E (SSR), which inhibits fibroblast growth factor receptor (FGFR) signaling by binding to the extracellular FGFR domain without affecting orthosteric FGF binding. SSR exhibits allosteric properties, including probe dependence, signaling bias, and ceiling effects. Inhibition by SSR is highly conserved throughout the animal kingdom. Oral delivery of SSR inhibits arthritis and tumors that are relatively refractory to anti-vascular endothelial growth factor receptor-2 antibodies. Thus, orally-active extracellularly acting small-molecule modulators of RTKs with allosteric properties can be developed and may offer opportunities to improve anticancer treatment.

title: Long pentraxin‐3 as an epithelial–stromal fibroblast growth factor‐targeting inhibitor in prostate cancer
abstract: Fibroblast growth factors (FGFs) exert autocrine/paracrine functions in prostate cancer by stimulating angiogenesis and tumour growth. Here dihydrotestosterone (DHT) up‐regulates FGF2 and FGF8b production in murine TRAMP‐C2 prostate cancer cells, activating a FGF‐dependent autocrine loop of stimulation. The soluble pattern recognition receptor long pentraxin‐3 (PTX3) acts as a natural FGF antagonist that binds FGF2 and FGF8b via its N‐terminal domain. We demonstrate that recombinant PTX3 protein and the PTX3‐derived pentapeptide Ac‐ARPCA‐NH2 abolish the mitogenic response of murine TRAMP‐C2 cells and human LNCaP prostate cancer cells to DHT and FGFs. Also, PTX3 hampers the angiogenic activity of DHT‐activated TRAMP‐C2 cells on the chick embryo chorioallantoic membrane (CAM). Accordingly, human PTX3 overexpression inhibits the mitogenic activity exerted by DHT or FGFs on hPTX3_TRAMP‐C2 cell transfectants and their angiogenic activity. Also, hPTX3_TRAMP‐C2 cells show a dramatic decrease of their angiogenic and tumourigenic potential when grafted in syngeneic or immunodeficient athymic male mice. A similar inhibitory effect is observed when TRAMP‐C2 cells overexpress only the FGF‐binding N‐terminal PTX3 domain. In keeping with the anti‐tumour activity of PTX3 in experimental prostate cancer, immunohistochemical analysis of prostate needle biopsies from primary prostate adenocarcinoma patients shows that parenchymal PTX3 expression, abundant in basal cells of normal glands, is lost in high‐grade prostatic intraepithelial neoplasia and in invasive tumour areas. These results identify PTX3 as a potent FGF antagonist endowed with anti‐angiogenic and anti‐neoplastic activity in prostate cancer.

title: Basic fibroblast growth factor overexpression in endothelial cells: an autocrine mechanism for angiogenesis and angioproliferative diseases.
abstract: Basic fibroblast growth factor (bFGF) is expressed in vascular endothelium during tumor neovascularization and angioproliferative diseases. The ultimate significance of this observation is poorly understood. We have investigated the biological consequences of endothelial cell activation by endogenous bFGF in a mouse aortic endothelial cell line stably transfected with a retroviral expression vector harboring a human bFGF cDNA. Selected clones expressing M(r) 24,000, M(r) 22,000, and/or M(r) 18,000 bFGF isoforms were characterized by a transformed morphology and an increased saturation density. bFGF transfectants showed invasive behavior and sprouting activity in three-dimensional fibrin gels and formed a complex network of branching cord-like structures connecting foci of infiltrating cells when seeded on laminin-rich basement membrane matrix (Matrigel). The invasive and morphogenetic behavior was prevented by anti-bFGF antibody, revealing the autocrine modality of the process. The biological consequences of this autocrine activation were investigated in vivo. bFGF-transfected cells gave rise to highly vascularized lesions resembling Kaposi's sarcoma when injected in nude mice and induced angiogenesis in avascular rabbit cornea. When injected into the allantoic sac of the chick embryo, they caused an increase in vascular density and formation of hemangiomas in the chorioallantoic membrane. In conclusion, bFGF-overexpressing endothelial cells acquired an angiogenic phenotype and recruit quiescent endothelium originating angioproliferative lesions in vivo. These findings demonstrate that bFGF overexpression exerts an autocrine role for endothelial cells and support the notion that tumor neovascularization and angioproliferative diseases can be triggered by stimuli that induce vascular endothelium to produce its own autocrine factor(s).

title: Endothelial cells overexpressing basic fibroblast growth factor (FGF-2) induce vascular tumors in immunodeficient mice
abstract: Basic fibroblast growth factor (FGF-2) is expressed in vascular endothelium during tumor neovascularization and angioproliferative diseases, including vascular tumors and Kaposi's sarcoma (KS). We have investigated the in vivo biological consequences of endothelial cell activation by endogenous FGF-2 in a mouse aortic endothelial cell line transfected with a retroviral expression vector harboring a human FGF-2 cDNA and the neomycin resistance gene. FGF-2 transfectants, named pZipbFGF2-MAE cells, caused the rapid growth of highly vascularized, non-infiltrating tumors when injected in nude mice. In contrast, lesions grew poorly when cells were injected in immunocompetent syngeneic animals. Histologically, the tumors had the appearance of hemangioendothelioma with spindled areas resembling KS and with numerous CD31+ blood vessels and lacunae. Southern blot analysis of tumor DNA, as well as disaggregation of the lesion followed by in vitro cell culture, revealed that less than 10% of the cells in the tumor mass retain FGF-2 overexpression and neomycin resistance at 6–8 weeks post-injection. Nevertheless, in vitro G418 selection allowed the isolation from the tumor of a FGF-2-overexpressing cell population showing biochemical and biological characteristics similar to those of pZipbFGF2-MAE cells, including the capacity to originate vascular lesions when re-injected in nude mice. To evaluate the effect of angiostatic compounds on the growth and vascularization of pZipbFGF2-MAE cell-induced lesions, nude mice were treated weekly (100mg/kg, i.p.) with the angiostatic sulfonated distamycin A derivative 2,2′-(carbonyl-bis-[imino-N-methyl-4,2-pyrrole carbonyl-imino-{N-methyl-4,2-pyrrole}carbonylimino])-bis-(1,5-naphthalene) disulfonic acid (PNU 153429). The results demonstrate that PNU 153429 inhibits the growth of the lesions and causes a ∼50% decrease in CD31+ microvessel density. In conclusion, the data indicate that FGF-2-overexpressing endothelial cells cause vascular lesions in immunodeficient mice which may represent a novel model for opportunistic vascular tumors suitable for the evaluation of angiostatic compounds.

title: The Nucleotide Analog Cidofovir Suppresses Basic Fibroblast Growth Factor (FGF2) Expression and Signaling and Induces Apoptosis in FGF2-Overexpressing Endothelial Cells
abstract: Cidofovir [(S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine; (S)-HPMPC] is an antiviral drug that has been approved for the treatment of cytomegalovirus retinitis in patients with AIDS. Cidofovir also possesses potent activity against human papillomavirus-induced tumors in animal models and patients. We have recently shown that cidofovir inhibits the development of vascular tumors induced by basic fibroblast growth factor (FGF2)-overexpressing endothelial cells (FGF2-T-MAE) in mice. Here, we demonstrate that the inhibitory activity of cidofovir in FGF2-T-MAE cells may result from the specific induction of apoptosis. Cell cycle analysis revealed that cidofovir induces accumulation of cells in the S phase and, upon prolonged treatment, a significant increase in sub-G1 cells, exhibiting a subdiploid DNA content. Moreover, annexin V binding, an early event in apoptosis induction, was increased in cidofovir-treated FGF2-T-MAE cells. Cidofovir also caused nuclear fragmentation and the activation of caspase-3-like proteases, as evidenced by the cleavage of poly(ADP-ribose)polymerase. In addition, cidofovir treatment of FGF2-T-MAE cells resulted in a pronounced up-regulation of the tumor suppressor protein p53. However, the expression of Bax and Bcl-2 remained unchanged, and cidofovir did not induce the release of cytochrome c from the mitochondria. In addition, cidofovir did not suppress the phosphorylation of protein kinase B/Akt, a transmitter of antiapoptotic survival signals, or its downstream regulator Bad, indicating that the Akt pathway is not affected by cidofovir in FGF2-T-MAE cells. However, the compound inhibited the expression of FGF2 and FGF2 signaling through Erk42/44, as shown by Western blot analysis. Our results indicate that cidofovir inhibits the growth of FGF2-T-MAE cells via inhibition of FGF2 expression and signaling and via the induction of apoptosis. These findings suggest that the clinical use of cidofovir might be expanded to tumors that are not induced by oncogenic viruses.

title: Cidofovir inhibits growth of B16 melanoma cells in vivo
abstract: Cidofovir [(S)‐1‐(3‐hydroxy‐2‐phosphonyl‐methoxypropyl) cytosine] is a commercially available nucleotide analogue that has antiviral activity against a broad range of DNA viruses and is effective against human cytomegalovirus infection.  We aimed to study the effect of cidofovir on growth of the highly aggressive melanoma tumour arising from mouse melanoma B16 cells grafted subcutaneously in C57B16/J mice.  Mice were treated daily with systemic cidofovir at several doses. In treated and control groups, tumour growth was measured using a calliper, and histological studies were performed. In untreated mice, massive invasive melanoma tumours were observed on day 5 after tumour cell grafting. Cidofovir treatment gave a dose‐dependent reduction in tumour size. Tumour growth was inhibited by 62% at a dose of 37·5 mg kg−1 three times weekly, as compared with control mice treated with saline alone. At 67 mg kg−1 three times weekly, tumour growth was inhibited by 90%. Increasing the cidofovir dose to 50 or 100 mg kg−1 daily resulted in a gradual increase in the antitumoral effect of the compound. In one experiment, cidofovir was administered at 100 mg kg−1 five times weekly from the eighth day after the injection of tumour cells, when the tumour already had a volume of approximately 100 mm3. In the treatment group, on the 14th day the tumour volume was approximately 200 mm3, while in the control group it had increased to 750 mm3.  Although the mechanism is unknown, an antitumoral or antiangiogenic effect may be the reason for the activity of cidofovir in this model. In view of our findings, use of cidofovir should be further explored in the treatment of neoplastic diseases.

title: Regression of a cutaneous melanoma metastasis after intralesional cidofovir
abstract: A 45-year-old man first came to our department in October 1997 for the surgical treatment of a subungual melanoma on his left hallux. The toe was amputated to the distal phalanx, and three sentinel lymph nodes found on the left hand side of his groin were positive for metastatic colonization. The subsequent inguinalobturatory node clearance revealed no metastases in the 22 lymph nodes examined. In July 1999, a subcutaneous melanoma metastasis was noticed on his left thigh, and surgically removed. The patient refused systemic chemotherapy, immunotherapy or hyperthermic isolated limb perfusion. During the following months, new pink-red to blue-black papules and metastatic nodules spread on the lower part of his left leg. A total body computed tomography, performed in October 2001, revealed no internal organ metastases. Following an article by Redondo and colleagues that reported the regression of melanomas in guinea pigs after the systemic administration of cidofovir , and after both the approval of the local ethical committee and the informed, written consent of the patient had been obtained, one of his metastatic lesions, 5mm in size, and located on the left pretibial region, was treated with intralesional injections of cidofovir (Vistide, Pharmacia-Upjohn). For comparison, a 5 mm nodule on the same leg was injected with saline solution following an identical schedule. Cidofovir was administered three times, at a dose of 0.1 ml (7.5 mg of active principle) at 2 week intervals. Both cidofovir and the saline solution were injected intralesionally using a fine needle (26 G). The total volume injected into each lesion was 0.3 ml. The metastatic nodule became inflamed soon after the first administration, then started to flatten, and had disappeared completely after three booster doses and within 2 months from the beginning of the treatment, leaving a faint hyperpigmentation . No change was noted in the control metastatic lesion. Both the metastases were surgically removed. The one treated with cidofovir revealed no presence of neoplastic cells, while the control lesion showed the classical features of intradermal metastasis. No side effects or laboratory changes were registered apart from a local erythema and burning sensation.

title: Unravelling the complexity of metastasis — molecular understanding and targeted therapies
abstract: Despite recognizing the devastating consequences of metastasis, we are not yet able to effectively treat cancer that has spread to vital organs. The inherent complexity of genomic alterations in late-stage cancers, coupled with numerous heterotypic interactions that occur between tumour and stromal cells, represent fundamental challenges in our quest to understand and control metastatic disease. The incorporation of genomic and other systems level approaches, as well as technological breakthroughs in imaging and animal modelling, have galvanized the effort to overcome gaps in our understanding of metastasis. Future research carries with it the potential to translate the wealth of new knowledge and conceptual advances into effective targeted therapies.

title: Novel Anti-Metastatic Action of Cidofovir Mediated by Inhibition of E6/E7, CXCR4 and Rho/ROCK Signaling in HPV+ Tumor Cells
abstract: Cervical cancer is frequently associated with HPV infection. The expression of E6 and E7 HPV oncoproteins is a key factor in its carcinogenicity and might also influence its virulence, including metastatic conversion. The cellular mechanisms involved in metastatic spread remain elusive, but pro-adhesive receptors and their ligands, such as SDF-1α and CXCR4 are implicated. In the present study, we assessed the possible relationship between SDF-1α/CXCR4 signaling, E6/E7 status and the metastatic process. We found that SDF-1α stimulated the invasion of E6/E7-positive cancer cell lines (HeLa and TC-1) in Matrigel though CXCR4 and subsequent Rho/ROCK activation. In pulmonary metastatic foci generated by TC-1 cells IV injection a high proportion of cells expressed membrane-associated CXCR4. In both cases models (in vitro and in vivo) cell adhesion and invasion was abrogated by CXCR4 immunological blockade supporting a contribution of SDF-1α/CXCR4 to the metastatic process. E6 and E7 silencing using stable knock-down and the approved anti-viral agent, Cidofovir decreased CXCR4 gene expression as well as both, constitutive and SDF-1α-induced cell invasion. In addition, Cidofovir inhibited lung metastasis (both adhesion and invasion) supporting contribution of E6 and E7 oncoproteins to the metastatic process. Finally, potential signals activated downstream SDF-1α/CXCR4 and involved in lung homing of E6/E7-expressing tumor cells were investigated. The contribution of the Rho/ROCK pathway was suggested by the inhibitory effect triggered by Cidofovir and further confirmed using Y-27632 (a small molecule ROCK inhibitor). These data suggest a novel and highly translatable therapeutic approach to cervix cancer, by inhibition of adhesion and invasion of circulating HPV-positive tumor cells, using Cidofovir and/or ROCK inhibition.

title: Is tail vein injection a relevant breast cancer lung metastasis model?
abstract: TWO MOST COMMONLY USED ANIMAL MODELS FOR STUDYING BREAST CANCER LUNG METASTASIS ARE: lung metastasis after orthotopic implantation of cells into the mammary gland, and lung implantations produced after tail vein (TV) injection of cells. Tail vein injection can produce lung lesions faster, but little has been studied regarding the differences between these tumors, thus, we examined their morphology and gene expression profiles.



Syngeneic murine mammary adenocarcinoma, 4T1-luc2 cells, were implanted either subcutaneously (Sq), orthotopically (OS), or injected via TV in Balb/c mice. Genome-wide microarray analyses of cultured 4T1 cells, Sq tumor, OS tumor, lung metastases after OS (LMet), and lung tumors after TV (TVt) were performed 10 days after implantation.



Bioluminescence analysis demonstrated different morphology of metastases between LMet and TVt, confirmed by histology. Gene expression profile of cells were significantly different from tumors, OS, Sq, TVt or LMet (10,350 probe sets; FDR≤1%; P<0.0001). Sq tumors were significantly different than OS tumors (700 probe sets; FDR≤15%; P<0.01), and both tumor types (Sq and OS) were significantly different than LMet (1,247 probe sets; >1.5-fold-change; P<0.01), with no significant difference between TVt and LMet.



There were significant differences between the gene profiles of cells in culture and OS versus LMet, but there were no differences between LMet versus TVt. Therefore, the lung tumor generated by TVt can be considered genetically similar to those produced after OS, and thus TVt is a relevant model for breast cancer lung metastasis.

title: Organ selectivity for implantation survival and growth of B16 melanoma variant tumor lines.
abstract: The fate of bloodborne malignant melanoma cells selected for their enhanced ability to form lung colonies was examined to determine how specific tumor cells are arrested in certain organs during the experimental metastasis process. After murine B16 melanoma variant tumor cell lines with low (B16-F1) or high (B16-F10) survival and growth potential in vivo were admisistered by iv or intracardiac injections into syngeneic C57BL/6 mice, the quantitative distribution of [125l]5-iodo-2'-deoxyuridine (125IUDR)-labeled cells in the organs and subsequent formation of metastatic lung colonies were assessed. The initial distribution of viable tumor cells was dependent on the route of injection: Soon after iv injection, more 125IUDR-labeled B16 cells were localized in the lungs and fewer in the blood and other organs than after intracardiac injection. However, 1 day after the injection, the number of viable tumor cells in the lungs was independent of the route of injection, and at 14 days the quantity of resulting lung tumor colonies was similar. Variant line B16-F10 cells were better arrested and formed more tumors per input cell than B16-F1, regardless of the injection route. B16-F10 yielded only lung tumor colonies, whereas B16-F1 formed some extrapulmonary tumor growths. The results suggested that the ultimate fate of circulating tumor cells was not determined solely by nonspecific arrest in the capillary bed of the first organ encountered, and that in vivo selection could produce tumor line variants with organs preferences.

title: Differences in cell density associated with differences in lung-colonizing ability of B16 melanoma cells.
abstract: The B16 melanoma-derived low lung-colonizing variant B16-F1 and the high lung-colonizing variant B16-F10 retained their differential lung-colonizing abilities throughout at least 35 serial s.c. transplant generations. The majority of the cells originating from solid B16-F1 tumors had a higher density than did cells originating from solid B16-F10 tumors. Cell suspensions of unselected solid B16 melanomas contained two major subpopulations differing in their cell density. The subpopulation with the lower cell density was more efficient in lung tumor colony formation, following i.v. administration, than was the high-density subpopulation. Cloned tumors from low-density B16 cells were more efficient in lung colony formation than were cloned tumors from high-density cells.

title: Zebrafish embryo as a tool to study tumor/endothelial cell cross-talk.
abstract: Tumor/endothelial cell cross-talk plays a pivotal role in the growth, neovascularization and metastatic dissemination of human cancer. Recent observations have shown that the teleost zebrafish (Danio rerio) may represent a powerful experimental platform in cancer research. Various tumor models have been established in zebrafish adults, juveniles, and embryos and novel genetic tools and high resolution in vivo imaging techniques have been exploited. In particular, grafting of mammalian tumor cells in zebrafish embryo body may simulate early stages of tumor development, neovascularization, and local invasion whereas the injection of cancer cells in the bloodstream of zebrafish embryo may allow the study of metastatic homing and colonization. This review focuses on the recent advances in tumor xenotransplantation in zebrafish embryo for the in vivo study of the cancer neovascularization, invasion and metastatic processes. This article is part of a Special Issue entitled: Animal Models of Disease.

title: Cellular markers that distinguish the phases of hemangioma during infancy and childhood.
abstract: Hemangiomas, localized tumors of blood vessels, appear in approximately 10-12% of Caucasian infants. These lesions are characterized by a rapid proliferation of capillaries for the first year (proliferating phase), followed by slow, inevitable, regression of the tumor over the ensuing 1-5 yr (involuting phase), and continual improvement until 6-12 yr of age (involuted phase). To delineate the clinically observed growth phases of hemangiomas at a cellular level, we undertook an immunohistochemical analysis using nine independent markers. The proliferating phase was defined by high expression of proliferating cell nuclear antigen, type IV collagenase, and vascular endothelial growth factor. Elevated expression of the tissue inhibitor of metalloproteinase, TIMP 1, an inhibitor of new blood vessel formation, was observed exclusively in the involuting phase. High expression of basic fibroblast growth factor (bFGF) and urokinase was present in the proliferating and involuting phases. There was coexpression of bFGF and endothelial phenotypic markers CD31 and von Willebrand factor in the proliferating phase. These results provide an objective basis for staging hemangiomas and may be used to evaluate pharmacological agents, such as corticosteroids and interferon alfa-2a, which accelerate regression of hemangiomas. By contrast, vascular malformations do not express proliferating cell nuclear antigen, vascular endothelial growth factor, bFGF, type IV collagenase, and urokinase. These data demonstrate immunohistochemical differences between proliferating hemangiomas and vascular malformations which reflect the biological distinctions between these vascular lesions.

title: Block of AIDS-Kaposi's sarcoma (KS) cell growth, angiogenesis, and lesion formation in nude mice by antisense oligonucleotide targeting basic fibroblast growth factor. A novel strategy for the therapy of KS.
abstract: Kaposi's sarcoma (KS) is the most frequent tumor of HIV-1-infected individuals (AIDS-KS). Typical features of KS are proliferating spindle-shaped cells, considered to be the tumor cells of KS, and endothelial cells forming blood vessels. Basic fibroblast growth factor (bFGF), a potent angiogenic factor, is highly expressed by KS spindle cells in vivo and after injection in nude mice it induces vascular lesions closely resembling early KS in humans. Similar lesions are induced by inoculating nude mice with cultured spindle cells from AIDS-KS lesions (AIDS-KS cells) which produce and release bFGF. Here we show that phosphorothioate antisense (AS) oligonucleotides directed against bFGF mRNA (ASbFGF) inhibit both the growth of AIDS-KS cells derived from different patients and the angiogenic activity associated with these cells, including the induction of KS-like lesions in nude mice. These effects are due to the block of the production of bFGF which is required by AIDS-KS cells to enter the cell cycle and which, after release, mediates angiogenesis. The effects of ASbFGF are specific, dose dependent, achieved at low (0.1-1 microM), nontoxic, oligomer concentrations, and are reversed by the addition of bFGF to the cells, suggesting that ASbFGF oligomers are promising drug candidates for KS therapy.

title: Spectrum of tumor angiogenesis in the bone marrow of children with acute lymphoblastic leukemia.
abstract: It has been shown that solid tumors progress in concert with an induction of tumor angiogenesis. It is not known, however, whether a similar phenomenon occurs in leukemia. Angiogenesis was characterized immunohistochemically by factor VIII staining of bone marrow biopsies and quantified by assessment of microvessel density using previously described techniques. We evaluated bone marrow biopsies from 40 children with newly diagnosed, untreated acute lymphoblastic leukemia. In 22 of the patients, we also evaluated angiogenesis after the completion of remission induction chemotherapy. Control specimens were obtained from children undergoing staging evaluations at the time of diagnosis of solid tumors and lymphomas. Microvessels were counted throughout the entire core specimen in consecutive x 200 fields, and a median count per field (cpf) was calculated. In addition, the number of microvessels in the single x 200 field with the highest microvessel density was designated as the "hot spot." Biopsies from children with leukemia and from controls showed median microvessel densities of 42 and 6 counts per field, respectively (P < or = 0.0001). Microvessel density of the hot spots of leukemia specimens and controls were also significantly different, 51 and 8, respectively (P < or = 0.0001). A computer-aided three-dimensional reconstruction model of bone marrow vascularity showed a complex, arborizing branching of microvessels in leukemic specimens compared with single, straight microvessels without branching in controls. Urinary basic fibroblast growth factor, a potent angiogenic factor, was measured in 22 of the children with newly diagnosed leukemia and in 39 normal, age-matched controls. Urinary basic fibroblast growth factor levels were increased in all 22 patients before treatment, were variable during induction chemotherapy, and demonstrated statistically insignificant decreases at the time of complete remission. These findings suggest that leukemia cells induce angiogenesis in the bone marrow and that leukemia might be angiogenesis dependent and raise the possibility for a role of antiangiogenic drugs in the treatment of leukemia.

title: A high pretreatment serum basic fibroblast growth factor concentration is an independent predictor of poor prognosis in non-Hodgkin's lymphoma.
abstract: Basic fibroblast growth factor (bFGF) is a secreted multifunctional cytokine and a potent stimulator of angiogenesis in vivo. Elevated bFGF concentrations have been detected in the serum and urine of cancer patients. We measured bFGF by enzyme-linked immunosorbent assay from sera taken from 160 non-Hodgkin's lymphoma (NHL) patients before treatment and stored at -20 degrees C. The patients had been observed for at least 5 years or until death. Serum bFGF concentrations (S-bFGF) ranged from undetectable to 34.7 pg/mL (median, 3.3 pg/mL). S-bFGF was detectable with a similar frequency in all subtypes of NHL. A high pretreatment S-bFGF was associated with poor overall survival. The 5-year survival rate of the patients within the highest quartile of S-bFGF concentrations (S-bFGF = 5.5 pg/mL) was only 39%, in contrast to a 60% survival rate of the patients with lower S-bFGF (P =.019). A high S-bFGF (within the highest quartile) was associated with poor outcome also in large-cell diffuse and immunoblastic lymphomas (5-year survival rates of 28% v 56%, respectively; P =.027), which was the largest histologic subgroup (n = 66) within the series. In multivariate analyses, S-bFGF was an independent prognostic factor, both when the highest quartile was used as a cut-off value (P =.0079) and when S-bFGF and the other parameters were entered into the model as continuous variables (P =.024). In the multivariate analyses, S-bFGF had a noticeably stronger prognostic value than serum lactate dehydrogenase and the number of extranodal tumor sites, both of which are currently included as components in the International Prognostic Index.

title: Prognostic relevance of serum levels of the angiogenic peptide bFGF in advanced carcinoma of the head and neck treated by primary radiochemotherapy
abstract: The objective of this trial was to analyze the prognostic relevance of the angiogenic peptides basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), and matrix metalloproteinase‐2 (MMP‐2) in the serum of patients with advanced carcinoma of the head and neck treated by primary radiochemotherapy.

title: Soluble syndecan-1 and serum basic fibroblast growth factor are new prognostic factors in lung cancer.
abstract: Syndecan-1 is a ubiquitous and multifunctional extracellular matrix proteoglycan,which mediates basic fibroblast growth factor (bFGF) binding and activity. Shedding of syndecan-1 ectodomain from the plasma membrane is highly regulated. We evaluated the influence of soluble syndecan-1 and serum bFGF determined by ELISA on outcome in 184 lung cancer patients (non-small cell lung cancer, n = 138; small cell lung cancer, n = 46). Serum syndecan-1 and bFGF levels were determined from sera taken before treatment. The median follow-up of the patients alive (n = 21) was 8.1 years (range, 6.6-8.9 years). High serum syndecan-1 and bFGF levels tended to occur in the same patients (P = 0.044). When the serum values corresponding to the highest tertile were used as the cutoff value, the median survival time of the patients with a high serum syndecan-1 level (>59 ng/ml) was 4 months [95% confidence interval (CI), 3-6 months] as compared with 11 months (9-16 months) among those with lower serum levels (P = 0.0001), and the median survival time of the patients with a high bFGF level (>3.4 pg/ml) was 5 months (3-8 months) versus 11 months (8-14 months) in those with a lower level (P = 0.023). In general, the prognostic influence of both factors was independent of the histological subtype. Both serum syndecan-1 level (relative risk, 1.8; 95% CI, 1.1-3.1) and serum bFGF level (relative risk, 1.6; 95% CI, 1.0-2.7) had independent influence on survival in a multivariate survival analysis in non-small cell lung cancer. We conclude that high serum syndecan-1 and bFGF levels at diagnosis are associated with poor outcome in lung cancer.

title: Early increase in serum levels of the angiogenesis‐inhibitor endostatin and of basic fibroblast growth factor in melanoma patients during disease progression
abstract: Increased serum levels of angiogenesis‐related factors such as endostatin, vascular endothelial cell growth factor (VEGF) or basic fibroblast growth factor (bFGF) have been demonstrated for a variety of solid and nonsolid tumours. Therefore, these factors have been suggested as diagnostic and in some studies as prognostic tumour markers.

title: Basic fibroblast growth factor expression as a predictor of prognosis in pediatric high-grade gliomas.
abstract: Clinical and histopathological factors fail to adequately predict outcomes in children with high-grade gliomas, indicating a need to identify relevant biological markers of tumor behavior to guide therapeutic decision-making. Basic fibroblast growth factor (bFGF) is a mitogenic and angiogenic factor that has been observed to be overexpressed in a significant percentage of malignant gliomas, although the prognostic significance of this expression is unknown. To address this issue, the expression status of bFGF was examined immunohistochemically in a series of 27 archival pediatric malignant non-brainstem gliomas treated consecutively at our institution between 1975 and 1992. Tumors were categorized based on expression levels, and the association between expression status and outcome was examined. Sixteen cases showed high levels of expression of bFGF, and 11 showed low levels. There was no correlation between expression status and either tumor histology, patient age, or tumor location. However, there was a significant difference in outcome between patients with high levels of bFGF immunoreactivity and those with low expression. Median progression-free survival was >66 months in the low bFGF group as compared to 6 months in the high bFGF group (P = 0.006). Median overall survival was >66 months in the low bFGF group as compared to 18 months in the high bFGF group (P = 0.03). Tumor bFGF expression seems to be strongly associated with outcome in children with high-grade gliomas and, consequently, may serve as a biological correlate of patient prognosis in conjunction with other prognostic variables.

title: Expression of Hepatocyte Growth Factor and Basic Fibroblast Growth Factor as Prognostic Indicators in Gastric Cancer
abstract: We have investigated the correlations among hepatocyte growth factor (HGF) mRNA expression, basic fibroblast growth factor (bFGF) mRNA expression, tumor microvessel density (MVD), and clinical pathological features of gastric cancer in Chinese patients. In situ hybridization was used to detect the expression of HGF and bFGF mRNAs, and immunohistochemistry was used to detect CD34 in 105 gastric cancer tissues and in 20 normal control tissues. The rate of HGF mRNA expression in normal gastric tissues (25%) was significantly lower than that (57.1%) in tumor tissues (P < 0.01). The rates of HGF mRNA and bFGF mRNA expression and MVD in T3–T4 stage tissues were higher than those in T1–T2 stage tissues (P < 0.01); the HGF mRNA expression rate was directly correlated with the bFGF mRNA expression rate (P < 0.05), and they were also directly correlated with MVD (P < 0.01). The mean survival time and the 5‐year survival rate of patients who were positive for expression of HGF mRNA and bFGF mRNA and who had a MVD ≥ 39.5/0.72 mm2 were significantly shorter than those who did not express HGF mRNA and bFGF mRNA and who had a MVD <39.5/0.72 mm2. Both HGF and bFGF may participate in angiogenesis in gastric cancer and may be involved in tumor invasion and metastasis. HGF and bFGF mRNA expression can be used as useful parameters to evaluate the prognosis of gastric cancer. Anat Rec, 2009.

title: bFGF as an autocrine growth factor for human melanomas.
abstract: Normal human melanocytes in culture require specific additives such as basic fibroblast growth factor (bFGF) and dibutyryl cyclic adenosine monophosphate (dbcAMP) in order to proliferate in defined or serum-containing medium (Halaban et al., 1987). This stringent requirement is absent in cells derived from metastatic melanomas which not only proliferate in regular culture medium, but also produce a substance immunologically related to bFGF (Halaban et al., 1987). We show here that the mitogenic activity necessary for normal human melanocytes is constitutively present in several lines of human metastatic melanomas and that this activity is inactivated by anti-bFGF antibodies. Melanoma cells, but not normal melanocytes, express bFGF gene transcripts. Although the molecular mechanism underlying the abnormal expression of bFGF in melanomas is not known, the results suggest that bFGF acts as an autocrine growth factor in melanomas.

title: Fibroblast growth factors in cancer: therapeutic possibilities
abstract: The fibroblast growth factor (FGF) family of signalling molecules and its receptors (FGFRs) contribute to normal developmental and physiological processes. However, the subversion of this powerful growth stimulatory pathway has been implicated in the generation of a variety of pathological conditions. This review focuses on the role of FGF/FGFRs in cancer. The case will be made that this signalling pathway is associated with and functionally important for the growth of some human tumours. As such, FGF/FGFRs can be viewed as rational therapeutic oncology targets and strategies used to inhibit these molecules are discussed. The therapeutic exploitation of tumour-associated FGFR expression to deliver toxins or antiproliferative signals to tumour cells is also reviewed, as is the use of FGFs as protein therapeutics to alleviate the side effects of cancer therapy.

title: Multistep nature of metastatic inefficiency: dormancy of solitary cells after successful extravasation and limited survival of early micrometastases.
abstract: In cancer metastasis, only a small percentage of cells released from a primary tumor successfully form distant lesions, but it is uncertain at which steps in the process cells are lost. Our goal was to determine what proportions of B16F1 melanoma cells injected intraportally to target mouse liver 1) survive and extravasate, 2) form micrometastases (4 to 16 cells) by day 3, 3) develop into macroscopic tumors by day 13, and 4) remain as solitary dormant cells. Using in vivo videomicroscopy, a novel cell accounting assay, and immunohistochemical markers for proliferation (Ki-67) and apoptosis (TUNEL), we found that 1) 80% of injected cells survived in the liver microcirculation and extravasated by day 3, 2) only a small subset of extravasated cells began to grow, with 1 in 40 forming micrometastases by day 3, 3) only a small subset of micrometastases continued to grow, with 1 in 100 progressing to form macroscopic tumors by day 13 (in fact, most micrometastases disappeared), and 4) 36% of injected cells remained by day 13 as solitary cancer cells, most of which were dormant (proliferation, 2%; apoptosis, 3%; in contrast to cells within macroscopic tumors: proliferation, 91%; apoptosis/necrosis, 6%). Thus, in this model, metastatic inefficiency is principally determined by two distinct aspects of cell growth after extravasation: failure of solitary cells to initiate growth and failure of early micrometastases to continue growth into macroscopic tumors.

title: Intravascular origin of metastasis from the proliferation of endothelium-attached tumor cells: a new model for metastasis
abstract: Metastasis is a frequent complication of cancer, yet the process through which circulating tumor cells form distant colonies is poorly understood. We have been able to observe the steps in early hematogenous metastasis by epifluorescence microscopy of tumor cells expressing green fluorescent protein in subpleural microvessels in intact, perfused mouse and rat lungs. Metastatic tumor cells attached to the endothelia of pulmonary pre-capillary arterioles and capillaries. Extravasation of tumor cells was rare, and it seemed that the transmigrated cells were cleared quickly by the lung, leaving only the endothelium-attached cells as the seeds of secondary tumors. Early colonies were entirely within the blood vessels. Although most models of metastasis include an extravasation step early in the process, here we show that in the lung, metastasis is initiated by attachment of tumor cells to the vascular endothelium and that hematogenous metastasis originates from the proliferation of attached intravascular tumor cells rather than from extravasated ones. Intravascular metastasis formation would make early colonies especially vulnerable to intravascular drugs, and this possibility has potential for the prevention of tumor cell attachment to the endothelium.

title: Metastasis: a question of life or death
abstract: The metastatic process is highly inefficient — very few of the many cells that migrate from the primary tumour successfully colonize distant sites. One proposed mechanism to explain this inefficiency is provided by the cancer stem cell model, which hypothesizes that micrometastases can only be established by tumour stem cells, which are few in number. However, recent in vitro and in vivo observations indicate that apoptosis is an important process regulating metastasis. Here we stress that the inhibition of cell death, apart from its extensively described function in primary tumour development, is a crucial characteristic of metastatic cancer cells.

title: Role of angiogenesis in tumor growth and metastasis.
abstract: Angiogenesis is required for invasive tumor growth and metastasis and constitutes an important point in the control of cancer progression. Its inhibition may be a valuable new approach to cancer therapy. Avascular tumors are severely restricted in their growth potential because of the lack of a blood supply. For tumors to develop in size and metastatic potential they must make an "angiogenic switch" through perturbing the local balance of proangiogenic and antiangiogenic factors. Frequently, tumors overexpress proangiogenic factors, such as vascular endothelial growth factor, allowing them to make this angiogenic switch. Two strategies used in the development of antiangiogenic agents involve the inhibition of proangiogenic factors (eg, anti-vascular endothelial growth factor monoclonal antibodies) as well as therapy with endogenous inhibitors of angiogenesis, such as endostatin and angiostatin. Therapy with endogenous angiogenic inhibitors such as endostatin and angiostatin may reverse the angiogenic switch preventing growth of tumor vasculature. Preclinical studies have shown that endostatin effectively inhibits tumor growth and shrinks existing tumor blood vessels. Phase 1 clinical trials of endostatin and angiostatin are ongoing, and preliminary results show minimal toxicities.

title: Intracellular metabolism of the antiherpes agent (S)-1-[3-hydroxy-2-(phosphonylmethoxy)propyl]cytosine.
abstract: (S)-1-[3-Hydroxy-2-(phosphonylmethoxy)propyl]cytosine (HPMPC) is an antiviral phosphonate nucleotide analogue that displays activity against a range of herpesviruses. Anion exchange high performance liquid chromatography analysis of the 60% methanol extract from [14C]HPMPC-treated cells reveals the formation of three major metabolites. Two of these were identified as phosphorylated forms of HPMPC, HPMPC phosphate, and HPMPC diphosphate, by liberation of HPMPC upon acid digestion and coelution with synthetic standards on high performance liquid chromatography. The third metabolite, which is resistant to alkaline phosphatase cleavage but sensitive to phosphodiesterase, is proposed to be an HPMPC phosphate adduct. In herpes simplex virus-1-infected cells the same three metabolites are detected, at concentrations comparable to those in uninfected cells. When HPMPC is removed from the medium, the concentrations of the metabolites in cells decrease slowly, with half-lives of approximately 6, 17, and 48 hr for HPMPC phosphate, HPMPC diphosphate, and the HPMPC phosphate adduct, respectively. HPMPC diphosphate inhibits herpes simplex virus-1 and -2 DNA polymerases with a lower Ki than that for DNA polymerase alpha, and enzyme inhibition is competitive in each case. The formation and the persistence of HPMPC phosphates in cells and the selective inhibition of viral DNA polymerases by HPMPC diphosphate can explain why cells pretreated with HPMPC remain refractory to viral infection even long after HPMPC is removed from the medium.

title: Awakening guardian angels: drugging the p53 pathway
abstract: Currently, around 11 million people are living with a tumour that contains an inactivating mutation of TP53 (the human gene that encodes p53) and another 11 million have tumours in which the p53 pathway is partially abrogated through the inactivation of other signalling or effector components. The p53 pathway is therefore a prime target for new cancer drug development, and several original approaches to drug discovery that could have wide applications to drug development are being used. In one approach, molecules that activate p53 by blocking protein–protein interactions with MDM2 are in early clinical development. Remarkable progress has also been made in the development of p53-binding molecules that can rescue the function of certain p53 mutants. Finally, cell-based assays are being used to discover compounds that exploit the p53 pathway by either seeking targets and compounds that show synthetic lethality with TP53 mutations or by looking for non-genotoxic activators of the p53 response.

title: A new science-business paradigm in anticancer drug development.
abstract: Studies into the molecular mechanisms of cancer have revealed that, with a few exceptions, the disease lacks a specific drug target. Therefore, new anticancer drugs not only take many years and much money to develop but also might not outperform existing drugs. However, what are assumed to be unfavorable hallmarks of cancer, for example drug resistance, can be exploited for selective anticancer therapy and for protection of normal cells. Based on this paradigm, the drug discovery can be complemented by novel use of existing agents and even "failed" drugs. The pharmacological industry could develop low cost, effective therapeutic modalities, by "re-using" already marketed and late-stage products in cancer-selective therapeutic kits.

title: Old drugs--new uses.
abstract: In 1949 Henri Laborit, a French surgeon, used the antihistamine promethazine to treat surgical shock in the belief that inhibition of the autonomic nervous system would prevent adverse cardiovascular responses to hypotension . He found that it had some beneficial action and combined it with other drugs, in a so-called ‘lytic cocktail’, to prevent its adverse effects. The manufacturers of promethazine, Rhone–Poulenc, became interested and examined a range of phenothiazines that Paul Charpentier had synthesized as potential antihistamines . A chlorinated derivative of promazine showed great promise in animal experiments, but when he tried it in patients undergoing surgery Laborit noticed that they became relaxed and unperturbed by the prospect of the operation. This serendipitous observation led him to persuade the psychiatrists at the Val de Grace military hospital in Paris to use it. The director of neuropsychiatry, Joseph Hamon, gave it to a patient with acute mania, who became calm.

title: New uses for old drugs
abstract: It takes too long and costs too much to bring new drugs to market. So let's beef up efforts to screen existing drugs for new uses, argue Curtis R. Chong and David J. Sullivan Jr. Drug rediscovery is becoming big business. It is so costly to bring a new drug to market that drug companies are looking at their back catalogues and patent expirations with a new eye. As Curtis R. Chong and David J. Sullivan Jr explain, the screening of existing drugs for new activities is a valuable short-cut between the lab and the clinic. And a comprehensive screening campaign could be particularly useful in uncovering treatments for neglected diseases.

title: Phospholipase PLA2G7, associated with aggressive prostate cancer, promotes prostate cancer cell migration and invasion and is inhibited by statins
abstract: Prostate cancer is the second leading cause of cancer mortality in men in developed countries. Due to the heterogeneous nature of the disease, design of novel personalized treatments is required to achieve efficient therapeutic responses. We have recently identified phospholipase 2 group VII (PLA2G7) as a potential drug target especially in ERG oncogene positive prostate cancers. Here, the expression profile of PLA2G7 was studied in 1137 prostate cancer and 409 adjacent non-malignant prostate tissues using immunohistochemistry to validate its biomarker potential and putative association with disease progression. In order to reveal the molecular alterations induced by PLA2G7 impairment, lipidomic and gene expression profiling was performed in response to PLA2G7 silencing in cultured prostate cancer cells. Moreover, the antineoplastic effect of statins combined with PLA2G7 impairment was studied in prostate cancer cells to evaluate the potential of repositioning of in vivo compatible drugs developed for other indications towards anti-cancer purposes. The results indicated that PLA2G7 is a cancer-selective biomarker in 50% of prostate cancers and associates with aggressive disease. The alterations induced by PLA2G7 silencing highlighted the potential of PLA2G7 inhibition as an anti-proliferative, pro-apoptotic and anti-migratorial therapeutic approach in prostate cancer. Moreover, the anti-proliferative effect of PLA2G7 silencing was potentiated by lipid-lowering statins in prostate cancer cells. Taken together, our results support the potential of PLA2G7 as a biomarker and a drug target in prostate cancer and present a rationale for combining PLA2G7 inhibition with the use of statins in prostate cancer management.

title: Glipizide, an antidiabetic drug, suppresses tumor growth and metastasis by inhibiting angiogenesis
abstract: Angiogenesis is involved in the development, progression and metastasis of various human cancers. Herein, we report the discovery of glipizide, a widely used drug for type 2 diabetes mellitus, as a promising anticancer agent through the inhibition of tumor angiogenesis. By high-throughput screening (HTS) of an FDA approved drug library utilizing our in vivo chick embryo chorioallantoic membrane (CAM) and yolk sac membrane (YSM) models, glipizide has been identified to significantly inhibit blood vessel formation and development. Moreover, glipizide was found to suppress tumor angiogenesis, tumor growth and metastasis using xenograft tumor and MMTV-PyMT transgenic mouse models. We further revealed that the anticancer capability of glipizide is not attributed to its antiproliferative effects, which are not significant against various human cancer cell lines. To investigate whether its anticancer efficacy is associated with the glucose level alteration induced by glipizide application, glimepiride, another medium to long-acting sulfonylurea antidiabetic drug in the same class, was employed for the comparison studies in the same fashion. Interestingly, glimepiride has demonstrated no significant impact on the tumor growth and metastasis, indicating that the anticancer effects of glipizide is not ascribed to its antidiabetic properties. Furthermore, glipizide suppresses endothelial cell migration and the formation of tubular structures, thereby inhibiting angiogenesis by up-regulating the expression of natriuretic peptide receptor A. These findings uncover a novel mechanism of glipizide as a potential cancer therapy, and also for the first time, provide direct evidence to support that treatment with glipizide may reduce the cancer risk for diabetic patients.

title: Clinically used antirheumatic agent auranofin is a proteasomal deubiquitinase inhibitor and inhibits tumor growth
abstract: Proteasomes are attractive emerging targets for anti-cancer therapies. Auranofin (Aur), a gold-containing compound clinically used to treat rheumatic arthritis, was recently approved by US Food and Drug Administration for Phase II clinical trial to treat cancer but its anti-cancer mechanism is poorly understood. Here we report that (i) Aur shows proteasome-inhibitory effect that is comparable to that of bortezomib/Velcade (Vel); (ii) different from bortezomib, Aur inhibits proteasome-associated deubiquitinases (DUBs) UCHL5 and USP14 rather than the 20S proteasome; (iii) inhibition of the proteasome-associated DUBs is required for Aur-induced cytotoxicity; and (iv) Aur selectively inhibits tumor growth in vivo and induces cytotoxicity in cancer cells from acute myeloid leukemia patients. This study provides important novel insight into understanding the proteasome-inhibiting property of metal-containing compounds. Although several DUB inhibitors were reported, this study uncovers the first drug already used in clinic that can inhibit proteasome-associated DUBs with promising anti-tumor effects.

title: Metformin repositioning as antitumoral agent: selective antiproliferative effects in human glioblastoma stem cells, via inhibition of CLIC1-mediated ion current
abstract: Epidemiological and preclinical studies propose that metformin, a first-line drug for type-2 diabetes, exerts direct antitumor activity. Although several clinical trials are ongoing, the molecular mechanisms of this effect are unknown. Here we show that chloride intracellular channel-1 (CLIC1) is a direct target of metformin in human glioblastoma cells. Metformin exposure induces antiproliferative effects in cancer stem cell-enriched cultures, isolated from three individual WHO grade IV human glioblastomas. These effects phenocopy metformin-mediated inhibition of a chloride current specifically dependent on CLIC1 functional activity. CLIC1 ion channel is preferentially active during the G1-S transition via transient membrane insertion. Metformin inhibition of CLIC1 activity induces G1 arrest of glioblastoma stem cells. This effect was time-dependent, and prolonged treatments caused antiproliferative effects also for low, clinically significant, metformin concentrations. Furthermore, substitution of Arg29 in the putative CLIC1 pore region impairs metformin modulation of channel activity. The lack of drugs affecting cancer stem cell viability is the main cause of therapy failure and tumor relapse. We identified CLIC1 not only as a modulator of cell cycle progression in human glioblastoma stem cells but also as the main target of metformin's antiproliferative activity, paving the way for novel and needed pharmacological approaches to glioblastoma treatment.

title: The development of antiretroviral therapy and its impact on the HIV-1/AIDS pandemic.
abstract: In the last 25 years, HIV-1, the retrovirus responsible for the acquired immunodeficiency syndrome (AIDS), has gone from being an "inherently untreatable" infectious agent to one eminently susceptible to a range of approved therapies. During a five-year period, starting in the mid-1980s, my group at the National Cancer Institute played a role in the discovery and development of the first generation of antiretroviral agents, starting in 1985 with Retrovir (zidovudine, AZT) in a collaboration with scientists at the Burroughs-Wellcome Company (now GlaxoSmithKline). We focused on AZT and related congeners in the dideoxynucleoside family of nucleoside reverse transcriptase inhibitors (NRTIs), taking them from the laboratory to the clinic in response to the pandemic of AIDS, then a terrifying and lethal disease. These drugs proved, above all else, that HIV-1 infection is treatable, and such proof provided momentum for new therapies from many sources, directed at a range of viral targets, at a pace that has rarely if ever been matched in modern drug development. Antiretroviral therapy has brought about a substantial decrease in the death rate due to HIV-1 infection, changing it from a rapidly lethal disease into a chronic manageable condition, compatible with very long survival. This has special implications within the classic boundaries of public health around the world, but at the same time in certain regions may also affect a cycle of economic and civil instability in which HIV-1/AIDS is both cause and consequence. Many challenges remain, including (1) the life-long duration of therapy; (2) the ultimate role of pre-exposure prophylaxis (PrEP); (3) the cardiometabolic side-effects or other toxicities of long-term therapy; (4) the emergence of drug-resistance and viral genetic diversity (non-B subtypes); (5) the specter of new cross-species transmissions from established retroviral reservoirs in apes and Old World monkeys; and (6) the continued pace of new HIV-1 infections in many parts of the world. All of these factors make refining current therapies and developing new therapeutic paradigms essential priorities, topics covered in articles within this special issue of Antiviral Research. Fortunately, there are exciting new insights into the biology of HIV-1, its interaction with cellular resistance factors, and novel points of attack for future therapies. Moreover, it is a short journey from basic research to public health benefit around the world. The current science will lead to new therapeutic strategies with far-reaching implications in the HIV-1/AIDS pandemic. This article forms part of a special issue of Antiviral Research marking the 25th anniversary of antiretroviral drug discovery and development, Vol. 85, issue 1, 2010.

title: Progress in the knowledge and treatment of advanced pancreatic cancer: from benchside to bedside.
abstract: Ever since a pivotal study in 1997 demonstrated superiority of gemcitabine over 5-FU, gemcitabine monotherapy has, until recently, comprised the standard of care in patients with advanced pancreatic cancer. However, the emerging recognition of the pancreatic cancer microenvironment, including the particularly abundant stroma, as playing a key role in disease progression and resistance to chemotherapy has marked somewhat of a paradigm shift in the way treatment of advanced pancreatic cancer is viewed, with these very same biological defenses conversely offering an Achilles heel with which to combat this aggressive disease. Recently, this approach was validated for the first time in a pivotal phase III trial in which patients received nab-paclitaxel, a stroma-targeted drug, with gemcitabine. Overall survival was significantly (p<0.001) prolonged in the combination arm, compared with gemcitabine alone, and thus these convincing results pave the way forward for future treatment regimens that employ a multipronged approach, targeting not only the primary tumor but the surrounding microenvironment as well.

title: The Thymidine Phosphorylase Inhibitor 5′-O-Tritylinosine (KIN59) Is an Antiangiogenic Multitarget Fibroblast Growth Factor-2 Antagonist
abstract: 5′-O-Tritylinosine (KIN59) is an allosteric inhibitor of the angiogenic enzyme thymidine phosphorylase. Previous observations showed the capacity of KIN59 to abrogate thymidine phosphorylase–induced as well as developmental angiogenesis in the chicken chorioallantoic membrane (CAM) assay. Here, we show that KIN59 also inhibits the angiogenic response triggered by fibroblast growth factor-2 (FGF2) but not by VEGF in the CAM assay. Immunohistochemical and reverse transcriptase PCR analyses revealed that the expression of laminin, the major proteoglycan of the basement membrane of blood vessels, is downregulated by KIN59 administration in control as well as in thymidine phosphorylase- or FGF2-treated CAMs, but not in CAMs treated with VEGF. Also, KIN59 abrogated FGF2-induced endothelial cell proliferation, FGF receptor activation, and Akt signaling in vitro with no effect on VEGF-stimulated biologic responses. Accordingly, KIN59 inhibited the binding of FGF2 to FGF receptor-1 (FGFR1), thus preventing the formation of productive heparan sulphate proteoglycan/FGF2/FGFR1 ternary complexes, without affecting heparin interaction. In keeping with these observations, systemic administration of KIN59 inhibited the growth and neovascularization of subcutaneous tumors induced by FGF2-transformed endothelial cells injected in immunodeficient nude mice. Taken together, the data indicate that the thymidine phosphorylase inhibitor KIN59 is endowed with a significant FGF2 antagonist activity, thus representing a promising lead compound for the design of multitargeted antiangiogenic cancer drugs.