bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhancement of UVB radiation–mediated apoptosis by sanguinarine in HaCaT human immortalized keratinocytes
Authors: Reagan-Shaw Shannon , Breur Jorien , Ahmad Nihal
Published: March 2006

In this article, we studied the chemopreventive effects of sanguinarine on UVB-mediated responses in human HaCaT immortalized keratinocytes. For our studies, HaCaT cells were treated with a low dose (50 nmol/L) of sanguinarine for 24 hours followed by irradiation with UVB (15 or 30 mJ/cm2). Our data showed that UVB exposure, at both doses, resulted in decreased cell viability and increased apoptosis. Interestingly, pretreatment of the cells with sanguinarine caused a significant enhancement in the antiproliferative response of UVB. These responses on UVB and/or sanguinarine treatments were associated with (a) decrease in Bcl-2 and Bcl-XL and (b) increase in Bax, Bid, and Bak protein levels. Bax knockdown and Bcl-2 overexpression resulted in a rescue of HaCaT cells from sanguinarine-mediated apoptosis. DNA cell cycle analysis revealed that UVB treatment resulted in an accumulation of cells in the G2-M phase of the cell cycle, whereas pretreatment of sanguinarine resulted in a significant shift of cells in the S phase at a low UVB dose and a further accumulation of cells in the G2-M phase at a higher UVB dose. These effects on cell cycle were accompanied with modulations in the protein levels of cyclin (B1, E, and A) and cdc2 and cyclin-dependent kinase 1. Furthermore, sanguinarine treatment was found to result in significant modulations in p53, p66Shc, MsrA, and superoxide dismutase levels. Based on our data, we suggest the sanguinarine may protect skin cells from UVB-mediated damages via apoptotic elimination of damaged cells that escape programmed cell death and therefore possess a potential of clonal expansion. [Mol Cancer Ther 2006;5(2):418–29]
Anti-CD70 antibodies: a potential treatment for EBV+ CD70-expressing lymphomas
Authors: Israel Bruce F. , Gulley Margaret , Elmore Sandra , Ferrini Silvano , Feng Wen-hai , Kenney Shannon C.
Published: March 2006

A monoclonal antibody (Rituximab) directed against the B-cell surface antigen, CD20, is increasingly used as a therapy for B-cell lymphomas. However, CD20 is expressed on all normal mature B cells and hence is not a specific tumor target. In contrast, CD70 is expressed on highly activated lymphocytes as well as on many B-cell and T-cell lymphomas but is not expressed on the great majority of B cells and T cells. In this report, we have explored the potential utility of anti-CD70 monoclonal antibodies for treatment of CD70+ EBV+ B-cell lymphomas. Using two Burkitt's lymphoma lines (Raji and Jijoye) that express surface CD70 and a CD70− Burkitt's lymphoma line (Akata), we show that two different monoclonal antibodies directed against human CD70 allow rabbit and human complement to kill EBV+ B cells in a CD70-dependent manner in vitro. In the absence of complement, neither anti-CD70 antibody induced in vitro killing of CD70+ cell lines. Importantly, i.p. injection of anti-CD70 antibodies also inhibited the growth of CD70+ Burkitt's lymphoma cells in severe combined immunodeficient mice but did not inhibit the growth of CD70− Burkitt's lymphoma cells. These results suggest that anti-CD70 antibodies may be useful for the treatment of CD70+ B-cell lymphomas. [Mol Cancer Ther 2005;4(12):2037–44]
Cetuximab preclinical antitumor activity (monotherapy and combination based) is not predicted by relative total or activated epidermal growth factor receptor tumor expression levels
Authors: Wild Robert , Fager Krista , Flefleh Christine , Kan David , Inigo Ivan , Castaneda Stephen , Luo Feng (Roger) , Camuso Amy , McGlinchey Kelly , Rose William C.
Published: March 2006

Although Erbitux (cetuximab) has proven therapeutic benefit in the clinical setting, the molecular determinants predicting responsiveness to this agent are still not very well understood. Here, we assessed the relationship between basal total and activated (pY1068) epidermal growth factor receptor (EGFR) levels in a tumor and the responsiveness to cetuximab monotherapy or combination-based treatment using human xenograft models. Cetuximab treatment alone (0.25–1 mg/mouse/injection, q3d, i.p.) effectively delayed the growth of GEO and L2987 tumors by a minimum of 10 days corresponding to log cell kill values of ≥1.0. Borderline activity was seen in the A549 and WiDr xenografts. However, cetuximab failed to show any significant antitumor activity in the HT29, HCT116, LOVO, Colo205, LX-1, HCC70, and N87 models. All of the studied tumors had detectable yet variable levels of EGFR. For combination regimens, cetuximab (1 mg/mouse/injection, q3dx5, i.p.) and cisplatin (4.5 mg/kg/injection, q3dx5, i.v.) proved to be significantly more efficacious than individual monotherapies in the cisplatin-refractory yet cetuximab-responsive GEO tumor model (P < 0.001). However, no therapeutic enhancement was observed in the cisplatin and cetuximab weakly responsive A549 xenograft. Similarly, combinations of CPT-11 (48 mg/kg/injection, q3dx5, i.v.) with cetuximab (1 mg/mouse/injection, q3dx5, i.p.) failed to show any improvements over individual monotherapies in the cetuximab resistant/weakly responsive HT29, A549, and WiDr models. We conclude that preclinical activity associated with cetuximab monotherapy does not correlate directly with relative basal levels of total or activated (pY1068) EGFR in a tumor. Moreover, robust single-agent activity by cetuximab may be the best predictor for this agent to potentiate chemotherapy-mediated antitumor activities. [Mol Cancer Ther 2006;5(1):104–13]
Protein tyrosine phosphatase PRL-3 in malignant cells and endothelial cells: expression and function
Authors: Rouleau Cecile , Roy Andre , St. Martin Thia , Dufault Michael R. , Boutin Paula , Liu Dapei , Zhang Mindy , Puorro-Radzwill Kristin , Rulli Lori , Reczek Dave , Bagley Rebecca , Byrne Ann , Weber William , Roberts Bruce , Klinger Katherine , Brondyk William , Nacht Mariana , Madden Steve , Burrier Robert , Shankara Srinivas , Teicher Beverly A.
Published: March 2006

Protein tyrosine phosphatase PRL-3 mRNA was found highly expressed in colon cancer endothelium and metastases. We sought to associate a function with PRL-3 expression in both endothelial cells and malignant cells using in vitro models. PRL-3 mRNA levels were determined in several normal human endothelial cells exposed or unexposed to the phorbol ester phorbol 12-myristate 13-acetate (PMA) and in 27 human tumor cell lines. In endothelial cells, PRL-3 mRNA expression was increased in human umbilical vascular endothelial cells and human microvascular endothelial cells (HMVEC) exposed to PMA. An oligonucleotide microarray analysis revealed that PRL-3 was among the 10 genes with the largest increase in expression on PMA stimulation. Phenotypically, PMA-treated HMVEC showed increased invasion, tube formation, and growth factor–stimulated proliferation. A flow cytometric analysis of cell surface markers showed that PMA-treated HMVEC retained endothelial characteristics. Infection of HMVEC with an adenovirus expressing PRL-3 resulted in increased tube formation. In tumor cells, PRL-3 mRNA levels varied markedly with high expression in SKNAS neuroblastoma, MCF-7 and BT474 breast carcinoma, Hep3B hepatocellular carcinoma, and HCT116 colon carcinoma. Western blotting analysis of a subset of cell line lysates showed a positive correlation between PRL-3 mRNA and protein levels. PRL-3 was stably transfected into DLD-1 colon cancer cells. PRL-3-overexpressing DLD-1 subclones were assessed for doubling time and invasion. Although doubling time was similar among parental, empty vector, and PRL-3 subclones, invasion was increased in PRL-3-expressing subclones. In models of endogenous expression, we observed that the MCF-7 cell line, which expresses high levels of PRL-3, was more invasive than the SKBR3 cell line, which expresses low levels of PRL-3. However, the MDA-MB-231 cell line was highly invasive with low levels of PRL-3, suggesting that in some models invasion is PRL-3 independent. Transfection of a PRL-3 small interfering RNA into MCF-7 cells inhibited PRL-3 expression and cell invasion. These results indicate that PRL-3 is functional in both endothelial cells and malignant cells and further validate PRL-3 as a potentially important molecular target for anticancer therapy. [Mol Cancer Ther 2006;5(2):219–29]
Down-regulation of Notch-1 contributes to cell growth inhibition and apoptosis in pancreatic cancer cells
Authors: Wang Zhiwei , Zhang Yuxiang , Li Yiwei , Banerjee Sanjeev , Liao Joshua , Sarkar Fazlul H.
Published: March 2006

Pancreatic cancer remains the fourth most common cause of cancer-related death in the United States. Notch signaling plays a critical role in maintaining the balance among cell proliferation, differentiation, and apoptosis, and thereby may contribute to the development of pancreatic cancer. To characterize Notch pathway function in pancreatic cancer cells, we explored the consequences of down-regulation of Notch-1 in BxPC-3, HPAC, and PANC-1 pancreatic cancer cells. Using multiple cellular and molecular approaches such as 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, apoptosis assay, flow cytometry, gene transfection, real-time reverse transcription-PCR (RT-PCR), Western blotting, and electrophoretic mobility shift assay for measuring DNA binding activity of nuclear factor κB (NF-κB), we found that down-regulation of Notch-1 inhibited cell growth and induced apoptosis in pancreatic cancer cells. Notch-1 down-regulation also increased cell population in the G0-G1 phase. Compared with control, small interfering RNA–transfected cells decreased expression of cyclin A, cyclin D1, and cyclin-dependent kinase 2. We found up-regulation of p21 and p27, which was correlated with the cell cycle changes. In addition, Notch-1 down-regulation also induced apoptosis, which could be due to decreased Bcl-2 and Bcl-XL protein expression in pancreatic cancer cells. Because Notch-1 is known to cross-talk with another major cell growth and apoptotic regulatory pathway (i.e., NF-κB), we found that NF-κB is a downstream target of Notch because down-regulation of Notch reduced NF-κB activity. We also found that genistein, a prominent isoflavone, could be an active agent for the down-regulation of the Notch pathway. These findings suggest that Notch-1 down-regulation, especially by genistein, could be a novel therapeutic approach for the treatment of pancreatic cancer. [Mol Cancer Ther 2006;5(3):483–93]
AIM2 suppresses human breast cancer cell proliferation in vitro and mammary tumor growth in a mouse model
Authors: Chen I-Fen , Ou-Yang Fu , Hung Jen-Yu , Liu Jaw-Ching , Wang Hongying , Wang Shao-Chun , Hou Ming-Feng , Hortobagyi Gabriel N. , Hung Mien-Chie
Published: March 2006

IFN-inducible proteins are known to mediate IFN-directed antitumor effects. The human IFN-inducible protein absent in melanoma 2 (AIM2) gene encodes a 39-kDa protein, which contains a 200-amino-acid repeat as a signature of HIN-200 family (hematopoietic IFN-inducible nuclear proteins). Although AIM2 is known to inhibit fibroblast cell growth in vitro, its antitumor activity has not been shown. Here, we showed that AIM2 expression suppressed the proliferation and tumorigenicity of human breast cancer cells, and that AIM2 gene therapy inhibited mammary tumor growth in an orthotopic tumor model. We further showed that AIM2 significantly increased sub-G1 phase cell population, indicating that AIM2 could induce tumor cell apoptosis. Moreover, AIM2 expression greatly suppressed nuclear factor-κB transcriptional activity and desensitized tumor necrosis factor-α–mediated nuclear factor-κB activation. Together, these results suggest that AIM2 associates with tumor suppression activity and may serve as a potential therapeutic gene for future development of AIM2-based gene therapy for human breast cancer. [Mol Cancer Ther 2006;5(1):1–7]
RRR-α-Tocopherol succinate down-regulates oncogenic Ras signaling
Authors: Donapaty Sreenivasa , Louis Somaja , Horvath Elizabeth , Kun Jiang , Sebti Said M. , Malafa Mokenge P.
Published: March 2006

α-Tocopherol succinate (TS), an analogue of vitamin E, has growth-inhibitory activity in a wide spectrum of in vitro and in vivo cancer models. Here, we report that modulation of oncogenic Ras is associated with TS activity. TS inhibits the proliferation and induces apoptosis of NIH3T3 cells stably transfected with oncogenic K-Ras and H-Ras, but not NIH3T3 cells expressing empty vector. TS treatment resulted in decreased Ras protein levels in oncogenic Ras expressing NIH3T3 cells but not in parental NIH3T3 cells. Treatment with TS suppressed the levels of phospho-Akt and phospho-Erk1/2 in oncogenic Ras expressing NIH3T3 cells. Overexpression of constitutively active phosphoinositide-3-kinase, Akt, and Mek1/2 significantly attenuated TS growth inhibition of oncogenic Ras-transformed NIH3T3 mouse fibroblast cell lines. In addition, transcriptional targets of oncogenic Ras such as c-Myc, cyclin D1, and E2F1 were down-regulated by TS in oncogenic Ras-expressing cells. The above TS effects on oncogenic Ras signaling were also observed in endogenous oncogenic K-Ras expressing HCT 116 (human colon cancer) and MDA-MB-231 (human breast cancer) cells. Taken together, these data show that TS down-regulation of the Ras signaling pathways that are mediated by Mek/Erk and phosphoinositide-3-kinase/Akt plays, at least in part, a critical role in TS inhibition of proliferation and survival of transformed cells. This data supports further investigation of the chemopreventive and therapeutic potential of TS in tumors that are dependent on activated Ras signaling and identifies phosphor-Erk and phosphor-Akt as potential biomarkers of TS activity. [Mol Cancer Ther 2006;5(2):309–16]
Rosiglitazone suppresses human lung carcinoma cell growth through PPARγ-dependent and PPARγ-independent signal pathways
Authors: Han ShouWei , Roman Jesse
Published: March 2006

Peroxisome proliferator-activated receptors γ (PPARγ) exert diverse effects on cancer cells. Recent studies showed that rosiglitazone, a synthetic ligand for PPARγ, inhibits cell growth. However, the exact mechanisms underlying this effect are still being explored, and the relevance of these findings to lung cancer remains unclear. Here, we report that rosiglitazone reduced the phosphorylation of Akt and increased phosphatase and tensin homologue (PTEN) protein expression in non–small cell lung carcinoma (NSCLC) cells (H1792 and H1838), and this was associated with inhibition of NSCLC cell proliferation. These effects were blocked or diminished by GW9662, a specific PPARγ antagonist. However, transfection with a CMX-PPARγ2 overexpression vector restored the effects of rosiglitazone on Akt, PTEN, and cell growth in the presence of GW9662. In addition, rosiglitazone increased the phosphorylation of AMP-activated protein kinase α (AMPKα), a downstream kinase target for LKB1, whereas it decreased phosphorylation of p70 ribosomal protein S6 kinase (p70S6K), a downstream target of mammalian target of rapamycin (mTOR). Of note, GW9662 did not affect the phosphorylation of AMPKα and p70S6K protein. The inhibitory effect of rosiglitazone on NSCLC cell growth was enhanced by the mTOR inhibitor rapamycin; however, it was blocked, in part, by the AMPKα small interfering RNA. Taken together, these findings show that rosiglitazone, via up-regulation of the PTEN/AMPK and down-regulation of the Akt/mTOR/p70S6K signal cascades, inhibits NSCLC cell proliferation through PPARγ-dependent and PPARγ-independent signals. [Mol Cancer Ther 2006;5(2):430–7]
Synthetic triterpenoid 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid induces growth arrest in HER2-overexpressing breast cancer cells
Authors: Konopleva Marina , Zhang Weiguo , Shi Yue-Xi , McQueen Teresa , Tsao Twee , Abdelrahim Maen , Munsell Mark F. , Johansen Mary , Yu Dihua , Madden Timothy , Safe Stephen H. , Hung Mien-Chie , Andreeff Michael
Published: March 2006

HER2 overexpression is one of the most recognizable molecular alterations in breast tumors known to be associated with a poor prognosis. In the study described here, we explored the effect of HER2 overexpression on the sensitivity of breast cancer cells to the growth-inhibitory effects of 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid (CDDO), a synthetic triterpenoid, both in vitro and in vivo in a xenograft model of breast cancer. Both cell growth and colony formation in the soft agar assay, a hallmark of the transformation phenotype, were preferentially suppressed in HER2-overexpressing cell lines at low concentrations of CDDO, whereas growth-inhibitory effects at high concentrations did not correlate with the expression level of HER2. CDDO dose-dependently inhibited phosphorylation of HER2 in HER2-overexpressing cells and diminished HER2 kinase activity in vitro. CDDO induced the transactivation of the nuclear receptor peroxisome proliferator-activated receptor-γ in both vector control and HER2-transfected MCF7 cells. Dose-response studies showed that the growth inhibition seen at lower concentrations of CDDO correlated with induction of the tumor suppressor gene caveolin-1, which is known to inhibit breast cancer cell growth. CDDO also reduced cyclin D1 mRNA and protein expression. In vivo studies with liposomally encapsulated CDDO showed complete abrogation of the growth of the highly tumorigenic MCF7/HER2 cells in a xenograft model of breast cancer. These findings provide the first in vitro and in vivo evidence that CDDO effectively inhibits HER2 tyrosine kinase activity and potently suppresses the growth of HER2-overexpressing breast cancer cells and suggest that CDDO has a therapeutic potential in advanced breast cancer. [Mol Cancer Ther 2006;5(2):317–28]
Radiosensitization of lung cancer by nutlin, an inhibitor of murine double minute 2
Authors: Cao Carolyn , Shinohara Eric T. , Subhawong Ty K. , Geng Ling , Woon Kim Kwang , Albert Jeffrey M. , Hallahan Dennis E. , Lu Bo
Published: March 2006

p53 plays a critical role in cell cycle arrest and induction of apoptosis. Certain malignancies carry wild-type p53, which is frequently down-regulated by murine double minute 2 (MDM2) overexpression. Availability of a small-molecule inhibitor against MDM2, nutlin, has made it feasible to evaluate the anti-MDM2-based therapeutic strategies. The rationale for the current study is that functional p53 has been linked with improved responses to radiation treatment. Hence, this study evaluates the use of nutlin, a small-molecule inhibitor that blocks the interaction of p53 and MDM2, in sensitizing cancer cells to radiation. Expression of MDM2, p53, and p21 in both p53 wild-type and p53-defective lung cancer cell lines was examined. Clonogenic and 7-amino-actinomycin D studies were used to determine possible mechanisms of cell death. The combined effect of MDM2 inhibition and radiation on cell cycle was also studied. We found that radiosensitization by nutlin occurs in lung cancer cells with wild-type p53. There were increased apoptosis and cell cycle arrest following administration of nutlin and radiation. Furthermore, the combination of nutlin and radiation decreased the ability of endothelial cells to form vasculature, as shown by Matrigel assays. Our data suggest that nutlin is an effective radiosensitizer of p53 wild-type cells. The radiosensitizing effect seems to be at least partially due to induction of apoptosis and cell cycle arrest. In addition, nutlin may be an effective radiosensitizer of tumor vasculature. [Mol Cancer Ther 2006;5(2):411–7]
Acquired resistance to TRAIL-induced apoptosis in human ovarian cancer cells is conferred by increased turnover of mature caspase-3
Authors: Lane Denis , Côté Marceline , Grondin Roxanne , Couture Marie-Christine , Piché Alain
Published: March 2006

Little is known on how cancer cells can acquire resistance to tumor necrosis factor–related apoptosis-inducing ligand (TRAIL). In this study, we established TRAIL-resistant cells from the TRAIL-sensitive human ovarian carcinoma cell line OVCAR3 to evaluate the potential mechanisms of acquired resistance to TRAIL. The selected resistant cells were cross-resistant to Fas ligand but remained sensitive to drug-induced apoptosis. Expression of TRAIL receptors was not altered in TRAIL-resistant OVCAR3 cells. Cleavage of caspase-8 and caspase-3 occurred in both TRAIL-resistant and TRAIL-sensitive cells. However, mature caspase-3 fragments were not detected by immunoblot in TRAIL-resistant cells and caspase-3 activity was significantly inhibited in these cells. The addition of proteasome inhibitors significantly increased TRAIL-induced apoptosis in resistant cells and enhanced the accumulation of mature caspase-3 fragments. Pretreatment with cycloheximide showed that active caspase-3 fragments have a high turnover rate in OVCAR3 R350 cells. X-linked inhibitor of apoptosis down-regulation by RNA interference also increased the accumulation of cleaved caspase-3 intermediates and resensitized TRAIL-resistant cells. Our findings show that altered turnover of mature caspase-3 may lead to acquired TRAIL resistance in ovarian cancer cells. Proteasome and X-linked inhibitor of apoptosis inhibitors could have a role in clinical situations to potentiate the cytotoxic effects of TRAIL in resistant tumor cells. [Mol Cancer Ther 2006;5(3):509–21]
Restriction of adenoviral replication to the transcriptional intersection of two different promoters for colorectal and pancreatic cancer treatment
Authors: Hoffmann Dennis , Wildner Oliver
Published: March 2006

In our current study, we developed oncolytic adenoviruses which preferentially lyse pancreatic and colon cancer cells by replacing viral E1 and/or E4 promoter with the tumor/tissue-specific promoters, cyclooxygenase-2 (COX-2), midkine (MK), or the cell cycle–dependent promoter, E2F1. We generated three sets of recombinant adenoviral vectors. In the first set, only the native E1A promoter was replaced by the COX-2, MK, or E2F1 promoter, respectively. In the second set, the viral E4 promoter was substituted by these heterologous promoters and the viral E1A promoter was substituted by the ubiquitously active cytomegalovirus-IE promoter. In the third set, we substituted the viral E1A and E4 promoters with the COX-2, MK, or E2F1 promoter, respectively. In our system, transcriptional targeting of solitary viral E1A resulted in 50% enhanced restricted vector replication when compared with an unrestricted replication-competent adenovirus. Furthermore, a targeted expression of the viral E1A gene products had a greater effect on restricted adenoviral replication than that of the E4 region. With our vectors, Ad.COX·MK and Ad.MK·COX, using two different heterologous promoters to control E1A and E4 expression, we showed enhanced viral replication specificity when compared with Ad.COX·COX or Ad.MK·MK, respectively. In a s.c. xenograft tumor model, there was no significant difference in the antineoplastic efficacy of the double heterologous promoter–controlled vectors when compared with our unrestricted replication-competent control adenovirus or vectors with only E1A transcriptionally driven by a heterologous promoter. [Mol Cancer Ther 2006;5(2):374–81]
Identification of a small topoisomerase I–binding peptide that has synergistic antitumor activity with 9-aminocamptothecin
Authors: Pond Christopher D. , Marshall Kathryn M. , Barrows Louis R.
Published: March 2006

The topoisomerase I (top1)–targeted camptothecin class of anticancer drugs is important in the treatment of several types of cancers. This class of drug inhibits the top1 enzyme during its catalytic DNA relaxation cycle, stabilizing the transient covalent top1-DNA complex by simultaneous noncovalent interactions with DNA and top1. We examined top1 using phage display because of the significance of this known top1-directed drug action. Several peptides that bind top1 were discovered and these were examined for top1 affinity, top1 catalytic and cleavage complex effects, and cytotoxic effects in cultured cell lines and in an in vivo tumor model. Although several peptides exhibited nanomolar and low-micromolar affinity for top1, none had cytotoxic effects when administered alone. However, in combination with 9-aminocamptothecin, one 15-mer peptide (SAYAATVRGPLSSAS) had synergistic cytotoxic effects with 9-aminocamptothecin both in the cytotoxicity assay and in nude mouse xenograft human tumor models. This report details the investigation of this peptide. [Mol Cancer Ther 2006;5(3):739–45]
Radiosensitization by the poly(ADP-ribose) polymerase inhibitor 4-amino-1,8-naphthalimide is specific of the S phase of the cell cycle and involves arrest of DNA synthesis
Authors: Noël Georges , Godon Camille , Fernet Marie , Giocanti Nicole , Mégnin-Chanet Frédérique , Favaudon Vincent
Published: March 2006

Radiosensitization caused by the poly(ADP-ribose) polymerase (PARP) inhibitor 4-amino-1,8-naphthalimide (ANI) was investigated in 10 asynchronously growing rodent (V79, CHO-Xrs6, CHO-K1, PARP-1+/+ 3T3, and PARP-1−/− 3T3) or human (HeLa, MRC5VI, IMR90, M059J, and M059K) cell lines, either repair proficient or defective in DNA-PK (CHO-Xrs6 and M059J) or PARP-1 (PARP-1−/− 3T3). Pulse exposure to ANI (1-hour contact) potentiated radiation response in rodent cells except in PARP-1−/− 3T3 fibroblasts. In contrast, ANI did not significantly enhance radiation susceptibility in asynchronously dividing human cells; yet, single-strand break rejoining was lengthened by ca. 7-fold in all but mouse PARP-1−/− 3T3s. Circumstantial evidence suggested that radiosensitization by ANI occurs in rapidly dividing cells only. Experiments using synchronized HeLa cells consistently showed that ANI-induced radiosensitization is specific of the S phase of the cell cycle and involves stalled replication forks. Under these conditions, prolonged contact with ANI ended in the formation of de novo DNA double-strand breaks hours after irradiation, evoking collision with uncontrolled replication forks of DNA lesions whose repair was impaired by inhibition of the PARP catalytic activity. The data suggest that increased response to radiotherapy by PARP inhibitors may be achieved only in rapidly growing tumors with a high S-phase content. [Mol Cancer Ther 2006;5(3):564–74]
Low doses of cisplatin or gemcitabine plus Photofrin/photodynamic therapy: Disjointed cell cycle phase-related activity accounts for synergistic outcome in metastatic non–small cell lung cancer cells (H1299)
Authors: Crescenzi Elvira , Chiaviello Angela , Canti Gianfranco , Reddi Elena , Veneziani Bianca Maria , Palumbo Giuseppe
Published: March 2006

We compared the effects of monotherapy (photodynamic therapy or chemotherapy) versus combination therapy (photodynamic therapy plus a specific drug) on the non–small cell lung cancer cell line H1299. Our aim was to evaluate whether the additive/synergistic effects of combination treatment were such that the cytostatic dose could be reduced without affecting treatment efficacy. Photodynamic therapy was done by irradiating Photofrin-preloaded H1299 p53/p16-null cells with a halogen lamp equipped with a bandpass filter. The cytotoxic drugs used were cis-diammine-dichloroplatinum [II] (CDDP or cisplatin) and 2′,2′-difluoro-2′-deoxycytidine (gemcitabine). Various treatment combinations yielded therapeutic effects (trypan blue dye exclusion test) ranging from additive to clearly synergistic, the most effective being a combination of photodynamic therapy and CDDP. To gain insight into the cellular response mechanisms underlying favorable outcomes, we analyzed the H1299 cell cycle profiles and the expression patterns of several key proteins after monotherapy. In our conditions, we found that photodynamic therapy with Photofrin targeted G0-G1 cells, thereby causing cells to accumulate in S phase. In contrast, low-dose CDDP killed cells in S phase, thereby causing an accumulation of G0-G1 cells (and increased p21 expression). Like photodynamic therapy, low-dose gemcitabine targeted G0-G1 cells, which caused a massive accumulation of cells in S phase (and increased cyclin A expression). Although we observed therapeutic reinforcement with both drugs and photodynamic therapy, reinforcement was more pronounced when the drug (CDDP) and photodynamic therapy exert disjointed phase-related cytotoxic activity. Thus, if photodynamic therapy is appropriately tuned, the dose of the cytostatic drug can be reduced without compromising the therapeutic response. [Mol Cancer Ther 2006;5(3):776–85]
NIK-333 inhibits growth of human T-cell leukemia virus type I-infected T-cell lines and adult T-cell leukemia cells in association with blockade of nuclear factor-κB signal pathway
Authors: Okudaira Taeko , Tomita Mariko , Uchihara Jun-Nosuke , Matsuda Takehiro , Ishikawa Chie , Kawakami Hirochika , Masuda Masato , Tanaka Yuetsu , Ohshiro Kazuiku , Takasu Nobuyuki , Mori Naoki
Published: March 2006

Adult T-cell leukemia (ATL) is caused by human T-cell leukemia virus type I (HTLV-I) and remains incurable. NIK-333, a novel synthetic retinoid, prevents the recurrence of human hepatoma after surgical resection of primary tumors. We explored the effects of NIK-333 on HTLV-I-infected T-cell lines and ATL cells. NIK-333 inhibited cell proliferation, induced G1 arrest, and resulted in massive apoptosis in all tested HTLV-I-infected T-cell lines and ATL cells, whereas little effect was observed on normal peripheral blood mononuclear cells. NIK-333 treatment decreases the levels of cyclin D1, cyclin D2, cIAP2, and XIAP proteins. Further analysis showed that NIK-333 inactivated nuclear factor-κB in HTLV-I-infected T-cell lines. In animal studies, treatment with NIK-333 (100 mg/kg given orally every other day) produced partial inhibition of growth of tumors of a HTLV-I-infected T-cell line transplanted s.c. in severe combined immunodeficient mice. Our results indicate that NIK-333 is a potentially useful therapeutic agent for patients with ATL. [Mol Cancer Ther 2006;5(3):704–12]
Inhibition of Akt survival pathway by a small-molecule inhibitor in human glioblastoma
Authors: Koul Dimpy , Shen Ruijun , Bergh Sherry , Sheng Xiaoyang , Shishodia Shishir , Lafortune Tiffany A. , Lu Yiling , de Groot John F. , Mills Gordon B. , Yung W.K. Alfred
Published: March 2006

Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) and Akt are important regulators of the phosphatidylinositol 3-kinase (PI3K) pathway and thus are important to the regulation of a wide spectrum of tumor-related biological processes. Akt regulates several critical cellular functions, including cell cycle progression; cell migration, invasion, and survival; and angiogenesis. Decreased expression of PTEN and overexpression of the Akt proto-oncogene, which is located downstream of PI3K, have been shown in a variety of cancers, including glioblastoma. Novel small-molecule inhibitors of receptors and signaling pathways, including inhibitors of the PI3K pathway, have shown antitumor activity, but inhibitors of Akt have not been examined. In this study, we tested our hypothesis that the pharmacologic inhibition of Akt has an antiproliferative effect on gliomas. We showed that two newly developed Akt inhibitors, KP-372-1 and KP-372-2 (herein called KP-1 and KP-2), effectively inhibited the PI3K/Akt signaling cascade. KP-1 and KP-2 blocked both the basal and epidermal growth factor–induced phosphorylation of Akt Ser473 at 125 and 250 nmol/L, which, in turn, reduced the activation of intracellular downstream targets of Akt, including GSK-3β and p70s6k. Furthermore, the treatment of U87 and U251 glioma cells with 125 to 250 nmol/L KP-1 and KP2 for 48 hours inhibited cell growth by ∼50%. This decrease in cell growth stemmed from the induction of apoptosis. Collectively, these results provide a strong rationale for the pharmacologic targeting of Akt for the treatment of gliomas. [Mol Cancer Ther 2006;5(3):637–44]
Spectrum of activity and molecular correlates of response to phosphatidylinositol ether lipid analogues, novel lipid-based inhibitors of Akt
Authors: Gills Joell J. , Holbeck Susan , Hollingshead Melinda , Hewitt Stephen M. , Kozikowski Alan P. , Dennis Phillip A.
Published: March 2006

The serine/threonine kinase Akt is a promising target in cancer. We previously identified five phosphatidylinositol ether lipid analogues (PIA) that inhibited Akt activation and selectively killed lung and breast cancer cells with high levels of Akt activity. To assess the spectrum of activity in other cell types and to compare PIAs with other inhibitors of the phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway, we compared growth inhibition by PIAs against the PI3K inhibitors LY294002 and wortmannin and the mTOR inhibitor rapamycin in the NCI60 cell line panel. Although each of these compounds inhibited the growth of all the cell lines, distinct patterns were observed. The PIAs were the least potent but the most cytotoxic. The broad spectrum of activity of PIAs was confirmed in vivo in hollow fiber assays. The response to PIAs was significantly correlated with levels of active but not total Akt in the NCI60, as assessed using COMPARE analysis. However, a number of molecular targets were identified whose expression was more highly correlated with sensitivity to PIAs than active Akt. Expression of these molecular targets did not overlap with those that correlated with sensitivity to LY294002, wortmannin, or rapamycin. A COMPARE analysis of the National Cancer Institute chemical screening database revealed that the patterns of activity of PIAs correlated best with patterns of activity of other lipid-based compounds. These studies show that although PIAs are widely active in cancer cells, which correlates with the presence of its intended target, active Akt, PIAs are biologically distinct from other known inhibitors of the PI3K/Akt/mTOR pathway. [Mol Cancer Ther 2006;5(3):713–22]
VKORC1
Haplotypes Are Associated With Arterial Vascular Diseases (Stroke, Coronary Heart Disease, and Aortic Dissection)
Authors: Wang Yibo , Zhang Weili , Zhang Yuhui , Yang Yuejin , Sun Lizhong , Hu Shengshou , Chen Jilin , Zhang Channa , Zheng Yi , Zhen Yisong , Sun Kai , Fu Chunyan , Yang Tao , Wang Jianwei , Sun Jing , Wu Haiying , Glasgow Wayne C. , Hui Rutai
Published: March 2006

Background—

The haplotypes in the gene vitamin K epoxide reductase complex subunit 1 (
VKORC1
) have been found to affect warfarin dose response through effects on the formation of reduced-form vitamin K, a cofactor for γ-carboxylation of vitamin K–dependent proteins, which is involved in the coagulation cascade and has a potential impact on atherosclerosis. We hypothesized that
VKORC1
-dependent effects on the coagulation cascade and atherosclerosis would contribute to susceptibility for vascular diseases.

Methods and Results—

To test the hypothesis, we studied the association of polymorphisms of
VKORC1
with stroke (1811 patients), coronary heart disease (740 patients), and aortic dissection (253 patients) compared with matched controls (n=1811, 740, and 416, respectively). Five common noncoding single-nucleotide polymorphisms of
VKORC1
were identified in a natural haplotype block with strong linkage disequilibrium (D′>0.9,
r
2
>0.9), then single-nucleotide polymorphism (SNP) +2255 in the block was selected for the association study. We found that the presence of the C allele of the +2255 locus conferred almost twice the risk of vascular disease (odds ratio [OR] 1.95, 95% confidence interval [CI] .58 to 2.41,
P
<0.001 for stroke; OR 1.72, 95% CI 1.24 to 2.38,
P
<0.01 for coronary heart disease; and OR 1.90, 95% CI 1.04 to 3.48,
P
<0.05 for aortic dissection). We also observed that subjects with the CC and CT genotypes had lower levels of undercarboxylated osteocalcin (a regulator for the bone), probably vascular calcification, and lower levels of protein induced in vitamin K absence or antagonism II (PIVKA-II, a des-γ-carboxy prothrombin) than those with TT genotypes.

Conclusions—

The haplotype of
VKORC1
may serve as a novel genetic marker for the risk of stroke, coronary heart disease, and aortic dissection.
An Administrative Claims Model Suitable for Profiling Hospital Performance Based on 30-Day Mortality Rates Among Patients With Heart Failure
Authors: Krumholz Harlan M. , Wang Yun , Mattera Jennifer A. , Wang Yongfei , Han Lein Fang , Ingber Melvin J. , Roman Sheila , Normand Sharon-Lise T.
Published: March 2006

Background—

A model using administrative claims data that is suitable for profiling hospital performance for heart failure would be useful in quality assessment and improvement efforts.

Methods and Results—

We developed a hierarchical regression model using Medicare claims data from 1998 that produces hospital risk-standardized 30-day mortality rates. We validated the model by comparing state-level standardized estimates with state-level standardized estimates calculated from a medical record model. To determine the stability of the model over time, we used annual Medicare cohorts discharged in 1999–2001. The final model included 24 variables and had an area under the receiver operating characteristic curve of 0.70. In the derivation set from 1998, the 25th and 75th percentiles of the risk-standardized mortality rates across hospitals were 11.6% and 12.8%, respectively. The 95th percentile was 14.2%, and the 5th percentile was 10.5%. In the validation samples, the 5th and 95th percentiles of risk-standardized mortality rates across states were 9.9% and 13.9%, respectively. Correlation between risk-standardized state mortality rates from claims data and rates derived from medical record data was 0.95 (SE=0.015). The slope of the weighted regression line from the 2 data sources was 0.76 (SE=0.04) with intercept of 0.03 (SE=0.004). The median difference between the claims-based state risk-standardized estimates and the chart-based rates was <0.001 (25th percentile=−0.003; 75th percentile=0.002). The performance of the model was stable over time.

Conclusions—

This administrative claims-based model produces estimates of risk-standardized state mortality that are very good surrogates for estimates derived from a medical record model.
Female size shows similar trends in all clades of the phylum Nematoda
Authors: Yeates Gregor W. , Boag Brian
Published: March 2006

To seek unifying principles underlying adult body size in the phylum
Nematoda, the volume of females of 3150 nematode species in 186 genera has
been calculated from published length and diameter information; genera are
grouped using the rDNA-based clades of De Ley et al. While the mass of
females in some of the clades overlap, there are usually distinct
differences within any particular clade between those nematodes that exist
in living substrates and those that do not, the latter invariably being
smaller. In all five clades (but not Chromadorida) the ability for females
to achieve relatively great size is normal, but diminutive females are known
from most clades and habitats. Bacterial feeding is common in females in
non-living substrates and related females in living substrates, which may
represent alternate generations, are often larger. If both groups of females
are bacterial feeding it would help to understand the conundrum of whether
those in living substrates are larger because they utilise better physical
conditions or are larger because they are required to produce more
propagules. Female body volume has previously been successfully used in
zoogeography and further investigations may include not only adult volume
but also address the question of stage-to-stage growth for which earlier
studies revealed a paucity of data. This survey of the phylum has not been
controlled for phylogeny, apart from the use of clades, and detailed studies
could be made within clades. In particular, the effect of substrate,
controlled through using species with alternate life cycles, should be
tractable.
On some selachinematid nematodes (Chromadorida: Selachinematidae) deposited in the collection of the Smithsonian National Museum of Natural History
Authors: Tchesunov Alexei V. , Okhlopkov Jury R.
Published: March 2006

A review and descriptions are given of some new or poorly known species of
the family Selachinematidae mounted in glycerin on slides deposited in the
nematode collection of the Smithsonian National Museum of Natural History,
Washington DC, USA, namely: Cheironchus vorax; C. conicaudatus sp. n.; C.
dactylocaudatus sp. n.; Gammanema uniformis (Cobb, 1920) comb. n., and
Synonchiella hopperi. All species were found along the Atlantic coast of the
USA. Species of the genus Cheironchus are characterised by details of the
mandibles that may be significant for species discrimination within the
genus. Three closely related species (Cheironchus vorax, C. paravorax and C.
conicaudatus sp. n.) share a similar form, the mandibles consisting of an
arm and two lateral palms with tiny hooks. The mandibles differ from one
another in the presence/absence of a denticulate crest and in the number of
palm hooks. The fourth species, C. dactylocaudatus sp. n., differs from the
other three species by having vestigial mandibles devoid of palm hooks,
presence of cheilostomatal sclerotisations and a tail with a posterior
cylindrical portion. All three Cheironchus species studied possess
extra-pharyngeal, longitudinal musculature around the anterior widening of
the pharynx. This musculature evidently acts to protrude the mandibles
beyond the oral aperture. An emended diagnosis of the genus Cheironchus is
provided. Gammanema uniformis comb. n. is recorded and described for the
first time since the original publication under the name Trogolaimus
uniformis Cobb, 1920. The genus Trogolaimus is regarded as a junior synonym
of Gammanema. Synonchiella hopperi is redescribed with a brief discussion of
its unique feature – an unpaired copulatory spicule.
Fertiliser use efficiency of soybean cultivars infected with Meloidogyne incognita and Pratylenchus penetrans
Authors: Melakeberhan Haddish
Published: March 2006

The most appropriate use of fertilisers to offset damage caused by nematode infestations can benefit greatly from determining fertiliser use efficiency (FUE). FUE is defined as increase in host productivity and/or decrease in nematode population density in response to a given fertiliser treatment. This study describes new and integrated approaches to identify FUE in nematode-infected plants. In two consecutive experiments, Heterodera glycines-resistant 'Bryan', susceptible-tolerant 'G88-20092', and susceptible-intolerant 'Tracy M' soybean cultivars were inoculated with 0 or 15 000 eggs of Meloidogyne incognita or mixed stages of Pratylenchus penetrans per 800 cm3 of sandy loam soil and maintained under glasshouse conditions (28 ± 2°C) for 25 and 26 days. Plants received 83 ± 21 and 89 ± 19 ml either full-strength Hoagland solution (HS), HS without N (HS-N), or tap water daily in Experiments 1 and 2, respectively. Photosynthesis and nematode population dynamics were chosen to test FUE because the relationship between these two parameters, for the most part, determines the outcome of crop yield in the presence of nematodes. Although the FUE varied by fertiliser source, cultivar and nematode, the data were conclusive in identifying the interactions. FUE was high for photosynthesis in all three cultivars, and more so in HS than in HS-N. FUE was high for suppressing population densities of both nematodes and increasing photosynthesis in cv. Tracy M and for M. incognita in cv. G88-20092. Fertiliser application against P. penetrans in cv. Bryan was unproductive because nematode population density increased. FUE for P. penetrans in cv. G88-20092 and for M. incognita in cv. Bryan was less conclusive because there was some increase in nematode population density. Overall, these new approaches to identifying FUE for host productivity in the presence of nematodes provide quantitative data that should be of great interest to plant breeders, soil scientists, agronomists and plant protection specialists.
Description of Pratylenchus dunensis sp. n. (Nematoda: Pratylenchidae), a root-lesion nematode associated with the dune grass Ammophila arenaria (L.) Link
Authors: de la Peña Eduardo , Moens Maurice , van Aelst Adriaanvan , Karssen Gerrit
Published: March 2006

A root-lesion nematode, Pratylenchus dunensis sp. n., is described and
illustrated from Ammophila arenaria (L.) Link, a grass occurring abundantly
in coastal dunes of Atlantic Europe. The new species is characterised by
medium sized (454-579 μ m) slender, vermiform, females and males having two
lip annuli (sometimes three to four; incomplete incisures only visible with
scanning electron microscopy), medium to robust stylet (ca 16 μ m) with
robust stylet knobs slightly set off, long pharyngeal glands (ca 42 μ m),
lateral field with four parallel, non-equidistant, lines, the middle ridge
being narrower than the outer ones, lateral field with partial areolation
and lines converging posterior to the phasmid which is located between the
two inner lines of the lateral field in the posterior half of the tail,
round spermatheca filled with round sperm, vulva at 78% of total body length
and with protruding vulval lips, posterior uterine sac relatively short (ca
19 μ m), cylindrical tail (ca 33 μ m) narrowing in the posterior third with
smooth tail tip and with conspicuous hyaline part (ca 2 μ m). Males occur
abundantly and present similar characteristics except for smaller dimensions
for all morphological characters, but the head region is more truncated in
outline than the female, spicule length is ca 15 μ m and testis length is ca
195 μ m. Nucleotide sequences of the rDNA expansion region D2D3 differed
from the morphologically similar species P. penetrans and P. brzeskii that
also occur in coastal dunes. These differences are supported by PCR-RFLP of
the ITS-rDNA. Pratylenchus dunensis sp. n. was also found parasitising roots
of Elymus farctus Viv.
Evaluation of Paecilomyces lilacinus strain 251 for the biological control of the northern root-knot nematode Meloidogyne hapla Chitwood
Authors: Kiewnick Sebastian , Sikora Richard A.
Published: March 2006

The egg-pathogenic fungus Paecilomyces lilacinus strain 251 (PL215) was
investigated under different temperature regimes for biocontrol activity
against the northern root-knot nematode Meloidogyne hapla. Biocontrol
activity by PL251 was affected by temperature and initial nematode inoculum
density. At 20/23°C (night/day) control efficacy reached 71% at a high
inoculum density of 10 000 eggs and juveniles (E + J) per 500 cm3 compared
to 65% control at the lower inoculum density (5000 E + J/500 cm3). By
contrast, average efficacy was 5% and 46% at low and high inoculum levels,
respectively, when temperatures were between 19°C and 21°C (night/day). A
significant interaction between the factors inoculum density and treatment
with PL251 was observed at low temperatures, when only few M. hapla galls
and egg masses developed after inoculation with 5000 E + J/500 cm3. When the
temperature was favourable for the fungal parasite (25°C), efficacy reached
90%. In glasshouse experiments with unfavourable temperatures for M. hapla
development (25°C-33°C), tomato plants repeatedly treated with PL251 showed
significantly higher fruit yield (23-102%).
Effect of fungus inoculation on the number of Bursaphelenchus xylophilus (Nematoda: Aphelenchoididae) carried by Monochamus alternatus (Coleoptera: Cerambycidae)
Authors: Maehara Noritoshi , Tsuda Kaku , Yamasaki Michimasa , Shirakikawa Shinsuke , Futai Kazuyoshi
Published: March 2006

To confirm the effects of wood-inhabiting fungi on the number of pine wood
nematodes (Bursaphelenchus xylophilus) carried by the Japanese pine sawyer
(Monochamus alternatus), we attempted to change the mycoflora and also to
prevent blue-stain fungi, the main food source fungi of the nematodes, from
spreading throughout pine wilt-killed Pinus densiflora wood by inoculating
12 other fungi into the dead logs. Trichoderma sp. 2, Trichoderma sp. 3, and
Verticillium sp. inoculation treatments tended to decrease the number of the
nematodes carried by the beetles. These fungi were more or less antagonistic
to the blue-stain fungus Ophiostoma minus, and Trichoderma sp. 2 and
Trichoderma sp. 3 grew faster than O. minus on four kinds of media.