bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1523: Caffeine antagonizes multidrug resistance by down-regulating ABCG2
Authors: Ding Rui , Shi Jia , Scotto Kathleen W.
Published: February 2011

ABCG2/BCRP (Breast Cancer Resistance Protein) is an ATP-binding-cassette (ABC) transporter that has been shown to confer multidrug resistance (MDR) in cancer cells, ultimately resulting in the failure of cancer chemotherapy. Accordingly, the downregulation of ABCG2 expression and/or function has been proposed as part of a regimen to improve cancer therapeutic efficacy. Caffeine and its analogs are a category of natural/synthetic and cell-permeable compounds that are used therapeutically in the treatment of occurring migraines and asthma, radiosensitization and obesity. In this study, we found that caffeine, at pharmacologically relevant concentrations, can dramatically decrease ABCG2 protein in cells that have either moderate (BeWo, a placental choriocarcimoma cell line) or high (MCF7/MX100 cells, a breast cancer drug resistant cell subline) levels of ABCG2 expression. This downregulation is time-dependent, dose-dependent, and reversible. Immunofluorescence studies revealed that caffeine treatment decreases membrane-localized ABCG2 protein and significantly increases the retentions of an established ABCG2 substrate in MCF7/MX100, but not in the parental cells, demonstrating that the caffeine-mediated downregulation of ABCG2 directly decreases drug efflux. Importantly, we found that caffeine can sensitize cells to the chemotherapeutic agent mitoxantrone (MX), where combination treatment with MX and caffeine decreased the IC50 of MX ∼10-fold and induced a greater degree of apoptotic cell death compared to MX treatment alone. Additionally, several caffeine analogs were tested and exhibited a similar ability to down-regulate ABCG2; theophylline (a metabolite of caffeine, also naturally found in tea) appeared to be the most potent. Taken together, these findings suggest that caffeine or caffeine analogs could be developed as combination therapy to improve the efficacy of drugs that are ABCG2 substrates.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1523.
Abstract 1530: Modulation of drug transporter expression in pancreatic cancer cells by indole-3-carbinol and gemcitabine: Potential transporter-targeted therapy
Authors: Lyn-Cook Beverly D. , Davis Cornelius , Wiley Kenneth , Word Beverly , Hammons George
Published: February 2011

Increased expression of drug transporters that induces multidrug resistance is a critical event in poor prognosis and treatment for numerous cancers, particularly pancreatic cancer. Due to its aggressive and resistance characteristics, prognosis is often fatal. Recently, investigators have focused on the use of inhibitors of proteins transcribed by various drug transporters as a potential target for improved therapy of various chemotherapeutics. Gemcitabine is the current treatment for pancreatic cancer, although some patients respond poorly to the treatment. Interindividual differences in expression of drug transporters relating to drug resistance has been a major factor in different drug outcomes. In the present study, pancreatic cancer cells (Panc-1 and SU86. 86) showed expression of the following drug transporters, ABCB1, ABCA5, MRP5, SLCO1B1, and SLC5A6. Gemcitabine treatment alone down-regulated expression of ABCA5, SLCO1B1, and SLC5A6 (P<0.05) transporters. Gemcitabine (0.1 µM) or I3C (100 µM) alone had no effect on ABCB1 expression. However, combination of gemcitabine (0.1µM) and indole-3-carbinol(100 µM) significantly down-regulated ABCB1. ABCB1 codes for the multidrug protein, pgp. This combination significantly inhibited growth of pancreatic cancer cells by 70%. Gemcitabine and indole-3 carbinol also decreased expression of MRP5 expression. These data suggest that dietary agents in combination with chemotherapeutics are potential inhibitors of multidrug resistance by down-regulating these proteins thus allowing for increased efficacy of the drug for treatment of the cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1530.
Abstract 154: Genome-wide profiling of histone and DNA methylation in prostate cells during EMT and malignant transformation
Authors: Ke Xi-Song , Qu Yi , Li Wen-Cheng , Yang Cheng , Rotter Varda , Oyan Anne Margrete , Kalland Karl-Henning
Published: February 2011

The loss of epithelial characteristics and the acquisition of a migratory phenotype, referred to as epithelial to mesenchymal transition (EMT), is a crucial event in tumor metastasis. Epigenetic modifications have been shown to be very critical in gene regulation during carcinogenesis, yet the role in EMT remains to be clarified. We report here a genome-wide analysis of histone methylation (H3K4me3 and H3K27me3), DNA methylation (DNAMe) and gene expression profiles in epithelial cells (EP156T) and their progeny mesenchymal cells (EPT1) and transformed cells (EPT2) in a cell culture model of stepwise prostate carcinogenesis. We found that H3K4me3 and H3K27me3 are very clear marks of active or repressed genes, while DNA methylation is only slightly associated with gene repression in all three cell lines. However, DNA methylation is a strong silencing mark when H3K4me3/DNAMe bivalently marked genes were excluded. Analysis of the transcription activities of genes with bivalent marks showed that H3K4me3/K27me3 is a repressive mark while H3K4me3/DNAMe is an active mark of gene expression. In individual genes, the transcription activities of genes with bivalent marks most likely correspond to the stronger mark. Furthermore, quantitative changes of H3K4me3 or H3K27me3 during EMT were correlated positively and negatively to activated and repressed transcription, respectively. Finally, a set of critical genes during EMT, including epithelial cell junction genes and the EMT inducers, FGFRs, were identified to show consistent changes concerning epigenetic modification and gene expression. All these findings provide the first blueprint of genome-wide epigenetic modification during EMT in prostate cells.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 154.
Abstract 1543: Up-regulation of CD52 enhances the resistance against bortezomib in multiple myeloma cells
Authors: Oh Jeong In , Park Juwon , Lee Chansu , Kim Byung-Su , Kwon Jung Hye , Kim Byoung Kook , Ahn Kwang-Sung , Yoon Sung-Soo
Published: February 2011

Bortezomib has excellent clinical activity in patients with multiple myeloma (MM). Clinical efficacy has been hampered by the emergence of drug-resistance phenomena. Verification of molecular mechanism by which resistance emerges is crucial for improved treatment outcome in MM. In this study, we established bortezomib resistance MM cells (U266/velR) and examined the biologic characteristics. In microarray analysis, 294 genes expressions were changed more than two-fold or greater and seven putative genes were selected by further analyzing microarray dataset. Those gene expressions between U266/velR and its control were confirmed using real-time RT-PCR. Among them, CD52, the lymphocyte surface marker, could be a target molecule to overcome bortezomib resistance. CD52 gene expression was examined in 6 different MM cell lines. Its expression was detected in U266, ARH77, and HS-sultan, but not in RPMI8226, IM9 and 536MM. The expression level of CD52 was correlated to the response of Bortezomib sensitivity. FASC analysis showed that CD52+ populations in U266/velR were 2.7 fold higher than those in control. When U266 cells were serially treated with Bortezomib, CD52 expression was gradually increased. In transfection analysis using full length cDNA of CD52 gene, transfected RPMI8226 cells were more resistant than parental cell. Our results suggested that Alemtuzumab was proposed as a therapeutic agent in bortezomib resistant myeloma patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1543.
Abstract 155: A comparison of DNA methylation in identical twins discordant for Hodgkin lymphoma
Authors: Cozen Wendy , Wang Jun , Siegmund Kim , Triche Timothy , Weisenberger Daniel , Van Den Berg David , Hamilton Ann , Hwang Amie , Mack Thomas M.
Published: February 2011

DNA methylation is an epigenetic change that may affect gene expression. Environmental determinants are largely unknown but strongly suspected. Because twins are matched on genome and to some extent, early life exposures, a comparison of DNA methylation between twins is of more interest than one between unrelated individuals.

To evaluate the possibility of an association between DNA methylation and young adult Hodgkin lymphoma (HL), DNA samples from blood or saliva were collected from both members of 25 identical twin pairs in whom one twin had developed HL prior to age 50 (discordant pairs). The median time since diagnosis was 16 years. DNA methylation status at 27,578 loci in 14,475 genes was measured in each sample using the Illumina Infinium methylation assay. We measured any difference (< or > 0) in the level of DNA methylation at each locus between the case and the unaffected co-twin and applied a paired t-test.

The overall pattern indicated that cases had higher levels of DNA methylation at loci with lower average DNA methylation levels, but the reverse was true at loci with higher overall levels of DNA methylation (e.g., here the cases had lower levels). With respect to specific loci, the HL case consistently had a higher level of DNA methylation compared to his/her unaffected co-twin at locus cg24693053 in the MFSD7 (major facilitator superfamily domain containing 7) gene in 22/25 pairs; this was also the locus with the most significant p-value (p= 0.0000332). Twenty-two out of 25 cases had a lower level of DNA methylation than their unaffected co-twin at loci cg17385448 in the AGMAT (Agmatine ureohydrolase [agmatinase]) gene (p= 0.0001587) and cg09809672 in the EDARADD (EDAR-associated death domain) gene (p= 0.003775846).

Seventeen out of 19 cases with the nodular sclerosis subtype had consistently higher DNA methylation levels at 9 loci and lower levels at 7 loci compared to their unaffected co-twin (binomial test p=0.0007). There was no overall effect on the pattern of methylation by time since diagnosis.

We observed suggestive differences in DNA methylation levels in normal peripheral blood mononuclear cells collected from young adult HL patients in remission relative to their unaffected identical co-twins. The differences may have resulted from HL disease or treatment, or could have pre-dated the diagnosis. The results are compatible with a role of the cumulative environment on DNA methylation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 155.
Abstract 1550: Small molecule inhibitors of ezrin as anti-metastatic agents in osteosarcoma
Authors: Bulut Gulay , Chen Kevin , Glasgow Eric , Hong Sung-Hyeok , Lee Hyun-Shik , Kosturko George , Toretsky Jeffrey A. , Daar Ira , Khanna Chand , Uren Aykut
Published: February 2011

Osteosarcoma (OS) is the most common type of primary bone cancer and the third most common cancer in children and adolescents. Current combination modalities have improved OS treatment, but did not have a major improvement on patient survival. Thus targeting underlying molecular events can provide dramatic benefits especially for the treatment of patients with fatal metastatic disease. Recently it is shown in a mouse model of OS that high ezrin expression is linked to pulmonary metastasis, providing an early survival advantage for cancer cells reaching the lung. Ezrin, a member of the ERM (Ezrin/Radixin/Moesin) family is conserved through evolution both structurally and functionally. By regulating membrane-cytoskeleton complexes, it plays key roles in normal cellular processes like maintenance of membrane dynamics, survival, adhesion, motility, cytokinesis, phagocytosis and integration of membrane transport with signaling pathways. Due to its critical role in these cellular functions and relevance to metastasis, ezrin is a validated molecular target for prevention of metastasis in OS. In order to identify small molecules that directly interact with recombinant ezrin protein, we screened a small molecule library by surface plasmon resonance technology (Biacore). Initial hits from this primary screen were then evaluated in functional assays. We tested our small molecules for inhibiting ezrin mediated chemotaxis in cell culture, mimicking ezrin morpholino phenotype in zebrafish development, inhibiting ezrin phosphorylation and ezrin-actin interaction, effecting xenopus embryo development and inhibiting lung metastasis of osteosarcoma cells in a mouse lung organ culture assay. Results from these secondary functional assays, binding kinetics values from Biacore experiments and drugability of the chemical structures allowed us to pick two lead compounds. In summary, we discovered two lead compounds that directly bind to ezrin protein with ∼10uM affinity and inhibit its function in multiple independent assays. These molecules form the foundation of new potential therapeutic agents for osteosarcoma metastasis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1550.
Abstract 1552: Isothiocyanates suppress human lung cancer cells metastasis
Authors: Yan Huiqin , Zhu Yu , Wu Xiang , Liu Boning , Li Ying , Liu Yunde , Zhou Qinghua , Xu Ke
Published: February 2011

Lung cancer is one of the most aggressive cancer types, and is the leading cause of cancer-related deaths worldwide. Metastasis is of great importance to the clinical management of cancer since it causes 90% of deaths from solid tumours. Therefore the development of novel anti-metastasis drugs becomes one of the most active fields in cancer research. Isothiocyanates are natural compounds found in consumable cruciferous vegetables. They have been shown to have the ability to inhibit chemical carcinogenesis by a wide variety of chemical carcinogens in animal models, inhibiting tumorigenesis in the lung, stomach, colon, liver, etc. Recent studies have also shown that isothiocyanates have antitumor activity, inhibiting several types of cultured human cancer cells growth, such as leukemia, prostate cancer and breast cancer. Our previous study also showed that isothiocyanates inhibit human lung cancer A549 cell growth. In the present study, we investigated the inhibitory effects of isothiocyanates on human lung cancer cell metastasis. We established a high-metastatic human large cell lung cancer cell line L9981, and found that both benzyl isothiocyanate (BITC) and phenethyl isothiocyanate (PEITC) inhibited L9981 cells growth in a dose-dependent manner, the IC50 values were 5.0±0.22 μM and 9.7±0.39 μM, respectively. Apoptosis was induced at 20 μM after 24 h. Transwell migration assay showed that the metastatic abilities of L9981 cells were suppressed by 96%, and metastasis-correlated genes were modulated. Cell cycle was arrested at G2/M phase. BITC and PEITC treatment resulted in reactive oxygen species (ROS) accumulation and severe glutathione (GSH) depletion. Akt activation was diminished. At transcription level, both nuclear transcription factors NFκB and AP-1 activities were suppressed. NFκB activities were reduced to 28.8% and 68.5% by BITC and PEITC, respectively; AP-1 activities were reduced to 17.8% and 80.9% by BITC and PEITC, respectively. Our results showed that BITC and PEITC suppress human lung cancer cells metastasis by induction of apoptosis, modulation of metastasis correlated gene expression, and induction of oxidative stress. This study indicates the potential use of isothiocyanates in treatment of advanced lung cancer. The signal transduction pathways and validation of cellular therapeutic targets of these isothiocyanates are under investigation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1552.
Abstract 1553: Activity of new matrix metalloproteinase inhibitors designed from 3D structure
Authors: Garcia-Sanmartin Josune , de Pablo-Maiso Lorena , Zapico Jose M. , Ramos Ana , de Pascual-Teresa Beatriz , Martinez Alfredo
Published: February 2011

Matrix metalloproteinases (MMPs) have been implicated in tumor development through enhancement of migration, angiogenesis, and metastasis. Therefore, MMP inhibitors (MMPIs) have been described as potential therapeutic agents for cancer treatment. However, clinical development of most MMPIs has been discontinued because of safety reasons due to their low specificity. The design of new MMPIs should pursue not only MMP blockade, but also preserving natural physiological processes that may be jeopardized by inhibition of the wrong class of MMPs. After prolonged research, only MMP1, 2, and 7 have been experimentally validated as cancer targets. On the other hand, reduction of some MMPs such as MMP3, 8, and 9 could enhance tumorigenesis and metastasis, so their inhibition should be avoided.

We describe here the activity of several novel MMPIs generated by computer assisted design and chemical synthesis that present a better inhibitory profile than previous compounds.

Inhibition of MMP2 and 9 activity by increasing concentrations of MMPIs was measured by gelatin zymography using human serum as the source of MMPs. The small molecules were added to the digestion buffer during an overnight incubation and zymogram bands were analyzed by densitometry. Their inhibitory activity was compared to the one elicited by 2R-[(4-biphenylsulfonyl)amino]-N-hydroxy-3-phenylpropinamide (BiPS), a commercially available MMP2/9 inhibitor. Our results show that some molecules inhibit MMP activity more strongly than BiPS, with an IC50 in the picomolar range. Specific MMP2 IC50 values of several of these small molecules were lower than the corresponding values for MMP9, presenting a promising MMP2/MMP9 inhibition ratio.

These inhibitors may be the basis for future therapeutic intervention strategies in cancer.CompoundIC50 MMP2 (pM)IC50 MMP9 (pM)RATIO MMP9/MMP2Zr208741.921097.831.48Zr224>5.00*103>50.00*103-Zr2689.4751.475.44Zr3371.5414.879.67Zr3502.4511.114.53Zr3667.7513.571.75Zr36710.0232.693.26Zr3681.9114.637.67Zr369325.511549.144.76

Calculated IC50 concentrations for MMP2 and MMP9 for several novel molecules

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1553.
Abstract 1555: In vitro and in vivo evaluation of analogs of N-(o-carboxybenzoyl)glutamic acid imide, an active thalidomide metabolite
Authors: Pather Kaveshree , Helsby Nuala A. , Palmer Brian D. , Ching Lai-Ming
Published: February 2011

Thalidomide, with its ability to inhibit angiogenesis and to inhibit the production of survival factors in the bone marrow, has proven to be very effective for the treatment of multiple myeloma. Previous studies from our laboratory identified 3 metabolites in the blood and urine of myeloma patients who were responding to thalidomide therapy (Lu et al, Clin Cancer Res. 9, 1680; 2003). One hydrolysis product, N-(O-carboxybenzoyl)glutamic acid imide (CGI) was as potent as lenalidomide in inhibiting angiogenesis and in inhibiting cytokine production in vitro. Structurally related molecules of CGI have been synthesised in an effort to produce analogs with improved potency, stability and activity. Analogs were each tested for activity for inhibition of tube formation by endothelial cells on matrigel and for inhibition of IL-6 production by RPMI-8226 myeloma cells stimulated by lipopolysacharide (LPS). Analogs with significantly improved potency compared to CGI in inhibiting tube formation and with less cytotoxicity have been synthesized. A tetra-fluorinated analog (SN 29900) was 17-fold and a morpholide-analog (SN 31721) was 8-fold more potent than CGI. SN 29900 was also better in inhibiting LPS-induced IL-6 production by RPMI-8226 cells provided 50% inhibition whilst SN 31721 provided only 15% inhibition at 10 µg/ml. SN 31721 and SN 29900 were both more stable than CGI at low pH levels. These analogs were well-tolerated in mice, with no signs of toxicity seen after an intra-peritoneal dose of 1000 mg/kg. Nor were toxicities observed following daily gavage at 200 mg/kg for 30 days. Plasma pharmacokinetics of SN 29900 and SN 31721 after an intra-peritoneal injection of 100 mg/kg was measured and the results indicated that the analogs were absorbed and cleared more rapidly than lenalidomide. The AUC0-∞ for SN 29900 and SN 31721 in mice was 41.1 µM.h and 162 µM.h respectively compared to 338 µM.h for lenalidomide at the same dose. Lenalidomide potentiates the activity of DMXAA, a vascular disrupting agent in phase III trials, against subcutaneous murine tumours. This was not observed with SN 29900, perhaps because of its poorer pharmacokinetic profile. Development of more lipophilic analogs that may have slower rates of clearance and improved pharmacokinetics are currently under development.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1555.
Abstract 1557: Corticorelin acetate exhibits preclinical antitumor activity, alone and with bevacizumab, against human brain tumor models
Authors: Gamez Maria I. , Ryan Robert P. , Keir Stephen T.
Published: February 2011

Corticorelin acetate is a synthetic form of corticotropin-releasing factor undergoing clinical trials in the treatment of peritumoral brain edema. We investigated preclinically its potential as an antitumor agent against orthotopically implanted human brain tumors, and its ability to enhance the therapeutic activity of bevacizumab in one of these models.

Intracranial (ic) tumor transplantation into the right cerebrum was performed using two patient-derived human tumor xenografts: D-341MED pediatric medulloblastoma and D-456MG pediatric multiforme glioblastoma. Mice were randomized 3 days after ic tumor implantation at which time all treatments were begun. Corticorelin acetate was administered at 0.1 and/or 0.2 mg mg/kg/dose, sc, twice daily (bid) depending upon the experiment. Bevacizumab was administered at a dose of 5 mg/kg/day, intraperitoneally (ip), twice weekly. Treatments were continued until a median day of death was reached for each group. In both studies antitumor effects were evaluated based on a survival analysis (Kaplan-Meier).

In the D-341MED, comparing treatments vs control, the low dose corticorelin acetate produced a 56% increase in life span (ILS) (p<0.001); the higher dose of corticorelin acetate yielded a 20% ILS which was also statistically different than the control group (p<0.05). In the D-456MG ic-implanted tumor experiment, corticorelin acetate (0.2 mg/kg/dose, bid, sc) achieved a 42% ILS (p<0.001) while bevacizumab produced a 64% ILS (p<0.001). When the two drugs on these same regimens were applied in combination, the resulting ILS of 92% (p<0.001 versus control) represented a therapeutic enhancement that was statistically different (p<0.05) from either solo drug treatment.

Conclusion: Corticorelin acetate significantly increased the lifespan of mice implanted orthotopically with two different pediatric brain tumor models. In the D-456MG model, in which corticorelin acetate and bevacizumab were evaluated, the combination produced a therapeutic outcome superior to that found using either of the two agents alone.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1557.
Abstract 1560: VE-PTP inhibitor AKB-9778 mitigates IL-2-induced VLS and interacts positively with IL-2 against melanoma and renal cancer tumors in mice
Authors: Cao Mingli , Lindner Dan , Borden Ernest , Shalwitz Robert , Yi Taolin
Published: February 2011

IL-2 induces complete responses (CR) durable more than 10 years in a subpopulation of patients with advanced melanoma or renal cell carcinoma, establishing the clinical effectiveness of immunotherapy for human malignancies. However, the application and clinical efficacy of IL-2 have been limited by its major dose-limiting toxicity vascular leak syndrome (VLS), which occurs in the majority (∼65%) of the patients and often necessitates cessation of the cytokine treatment. Being a life-threatening toxicity, VLS is managed by supportive care with no specific treatment. Therapeutics for IL-2-induced VLS might improve the efficacy and tolerance of the cytokine.

Recent studies implicated heightened Ang2 as a potential mediator of VLS via antagonizing Ang1 and thus blocking Tie2/AKT signaling in endothelial cells. Being a regulator of Tie2 phosphorylation, vascular endothelial protein tyrosine phosphatase (VE-PTP) might be targeted to modulate Tie2/AKT signaling although tthe effects and tolerance of targeting VE-PTP were not well-defined.

Our work herein identified compound AKB-9778 as a VE-PTP inhibitor capable of inducing pTie2 and down stream pAKT in endothelial cells, interacting positively with Ang1 and/or Ang2 to increase cellular pTie2 levels, reducing IL-2-induced circulating Ang2 in mice and protecting mice from IL-2-induced VLS. AKB-9778 also interacted positively with IL-2 against B16 melanoma and Renca renal cancer tumors in mice in a tolerated manner. These data provide pre-clinical proof of concept evidence of targeting VE-PTP to mitigate IL-2-induced VLS. AKB-9778 may provide beneficial adjunctive therapy in combination with IL-2 in cancer treatment by reducing VLS and enhancing efficacy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1560.
Abstract 1565: Pazopanib reveals B-Raf regulation of anti-angiogenesis pathways and prevents brain metastatic colonization of HER2+ breast cancer cells
Authors: Gril Brunilde , Palmieri Diane , Qian Yong , Vega-Valle Eleazar , Liewehr David J. , Steinberg Seth M. , Gilmer Tona M. , Kumar Rakesh , Rubin Stephen D. , Steeg Patricia S.
Published: February 2011

Brain metastases occur in approximately 35% of metastatic breast cancer patients whose tumors overexpress HER2. Using a quantitative model system to study breast cancer brain metastasis, HER2 overexpression increased the brain colonization of a brain seeking subline of MDA-MB-231 cells (231-BR-HER2). Since HER2 has been shown to induce overexpression of VEGF, we hypothesized that the anti-angiogenic drug pazopanib (GW786034) would reduce the metastatic outgrowth of breast cancer cells in the brain. Pazopanib is a multispecific tyrosine kinase inhibitor targeting VEGFR-1, −2, and −3, PDGFR-alpha and beta, and c-kit.

In vitro, pazopanib not only inhibited proliferation of human brain endothelial cells but also the 231-BR tumor cell line (IC50 = 4microM). Pazopanib disrupted the Erk signaling pathway despite the fact that 231-BR cells have a constitutively activated Ras pathway; expressing mutant K-Ras (codon13) and mutant B-Raf (G464V). Interestingly, using either purified B-Raf or cell lysates, we showed that pazopanib could directly inhibit B-Raf kinase activity as shown by a decreased in pMEK1/2. This data identifies a new mechanism of action of pazopanib as a direct inhibitor of B-Raf. Pazopanib inhibition of B-Raf was greater for the wild type enzyme and the G464V mutant than the V600E mutation.

The inhibition of Ras-Raf-ERK pathway by pazopanib was confirmed in vivo in xenograft models using seven different breast carcinoma and melanoma cell lines presenting different genotypes for the Ras-Raf-ERK pathway (mutation in Ras, mutation in B-Raf, overexpression of kinases upstream Ras (HER2) or wild type for the entire pathway). Anti-angiogenic potency in this cell line panel directly correlated with anti-B-Raf activity, suggesting that B-Raf pathways control angiogenic mediator production.

Finally we demonstrated that Pazopanib prevented the outgrowth of brain metastasis. In the brain metastasis mice model, 231-BR-HER2 cells produced a mean of 3.92 large metastases (>300microM) and 101.9 micro metastasis per brain section in the vehicle treated mice. Treatment with 30 mg/kg Pazopanib resulted in a 51% decline to 1.93 large metastases (p=0.0002) and 25% decrease to 76.4 micro metastasis (p=0.07), while treatment with 100 mg/kg resulted in a 73% decline to 1.05 large metastases (p<0.0001) and 39% decline in micro metastasis to 61.7 (p=0.004). These experiments contradict previous research claiming that anti-angiogenic agents promote metastasis, and support a clinical trial for the treatment or prevention of HER2+ brain metastases.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1565.
Abstract 1568: GLPG0187, a small molecule integrin antagonist, shows good safety and decrease in CTX levels in single ascending dose study
Authors: Lorenzon Giocondo , Gheyle Lien , Vets Eva , Namour Florence , Pujuguet Philippe , Clement-Lacroix Philippe , Wigerinck Piet , Vanhoutte Frederic
Published: February 2011

Introduction :

GLPG0187, a small molecule integrin antagonist with nanomolar affinity for the RGD-integrin receptors αvβ1, αvβ3, αvβ5, αvβ6 and α5β1, shows potent anti-angiogenic, anti-metastatic, anti-bone-resorption and anti-tumor activity in vitro and in vivo. Therefore GLPG0187 may offer a promising therapeutic approach for the treatment of integrin receptor expressing tumors and/or metastases.

Methods:

Based on promising preclinical data, a first-in-human study was performed with GLPG0187 to assess the safety and tolerability as well as pharmacokinetic and pharmacodynamic behavior of single ascending doses of the compound. GLPG0187 was administered subcutaneously in a dose range of 17.5 to 315 mg and orally in a dose range of 50 to 1200 mg.

Results:

GLPG0187 was systemically well tolerated with no adverse effects on ECG, vital signs or laboratory parameters. GLPG0187 showed a dose proportional pharmacokinetic profile over the dose range tested. Moreover, GLPG0187 dose proportionally decreased osteoclast activity as measured by plasma CTX (carboxy-terminal collagen crosslinks) levels.

Conclusions:

GLPG0187 was shown to be safe and well tolerated, to have a dose proportional pharmacokinetics and to inhibit osteoclast activity. These results provide further evidence that GLPG0187 could be an effective therapeutic for the treatment of cancer.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1568.
Abstract 1569: Antitumor activity of SR16388 against human multiple myeloma in vitro and in vivo
Authors: Chao Wan-Ru , Shi Yihui , Dinh Dominic , Hou Carol , Sambucetti Lidia
Published: February 2011

Multiple myeloma (MM) is the cancer of plasma cells that derive from a clonal disorder of terminally differentiated B cells in the bone marrow. MM is generally thought to be refractory against chemotherapeutics and is incurable. Development of novel agents for the treatment of this disease is urgently needed. Previous studies have indicated that MM cells express estrogen receptors (ERs), and anti-estrogens such as ICI 182,780 and Tamoxifen have demonstrated inhibitory effects on proliferation of MM cell lines as well as on MM cells isolated from patients. MM cells also over-express proangiogenic factors such as VEGF to induce angiogenesis and support their growth and survival. At SRI International, we have developed a steroidal anti-angiogenic molecule (SR16388) that potently inhibits angiogenesis in lung and prostate cancers, and it also binds to ER-α and ER-ß with high affinities in the nanomolar range. In this study, we examined the in vitro and in vivo effects of SR16388 on growth of MM cells. In RPMI-8226 multiple myeloma cells, SR16388 inhibited cell proliferation with an IC50 value of 0.9 µM. Cell cycle analysis revealed that SR16388 arrested the RPMI-8226 cells in G2 phase. In an in vivo murine xenograft model, SR16388 significantly inhibited the growth of RPMI-8226 tumors at the dose levels of 50 and 100 mg/kg with P < 0.05 and P < 0.02 respectively in a dose dependent manner. We are currently examining the molecular effects of SR16388 that contribute to its anti-proliferative and anti-angiogenic effects on MM and other human tumor types. Based on our in vitro and in vivo data, we believe that SR16388 is a promising new therapeutic molecule for the treatment of MM.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1569.
Abstract 1570: Silibinin inhibits invasive properties of human breast cancer cell line MDA-MB-231 through suppression of cathepsin B and extracellular signal-regulated kinase-mediated induction of matrix metalloproteinase 2 and 9
Authors: Nejati Mohammad R. , Momeny Majid , Ghaffari Seyed H. , Mojarrad Majid , Emami Amir H.
Published: February 2011

The purpose of the current study is to evaluate the effects of silibinin on human breast adenocarcinoma MDA-MB-231 cells. BrdU cell proliferation assay, Cell-based extracellular signal-regulated kinase (ERK) 1/2 activation assay, cathepsin B activity assay, Gelatin zymography and quantitative real-time RT-PCR were employed to appraise the effects of silibinin on DNA synthesis, ERK 1/2 phosphorylation, cathepsin B activity and gelatinolytic activity in MDA-MB-231 cells. Silibinin inhibited cell proliferation, ERK 1/2 activation, cathepsin B enzymatic levels and gelatinase activity in a dose-dependent manner. In addition, an expressive decrease in mRNA levels of cathepsin B, hyaluronidase-2 (Hyal-2), urokinase plasminogen activator receptor (uPAR), matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) coupled with a significant induction in transcriptional levels of tissue inhibitor of matrix metalloproteinase-2 (TIMP-2), Stefin A and Lipocalin 2 were observed. Altogether, these issues show for the first time that silibinin treatment could trammel cell growth and invasive features of a highly invasive human breast cancer cell line, MDA-MB-231, through suppression of ERK 1/2 both directly (through impeding ERK 1/2 phosphorylation) and indirectly (via transcriptional enhancement of Lipocalin 2). Furthermore, cramping enzymatic activity of cathepsin B by silibinin might cripple activation of gelatinases and thereby, reduces invasive potential in MDA-MB-231 cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1570.
Abstract 1572: The role of MIF signaling in melanoma progression
Authors: Oliveira Camila S. , Yan Xu Guang , Hersey Peter , Zhang Xu Dong , Thorne Rick F.
Published: February 2011

Melanoma is the most life-threatening form of skin cancer and although highly curable at the early stages, metastatic melanoma is incurable. One of the early events in melanoma progression is the activation of ERK and Akt signalling pathways, involved in proliferation, migration and survival. The causes of such kinase activation include mutations in BRAF, N-RAS and PTEN. Besides gene mutation, it has been shown that autocrine production of growth factors can also contribute to ERK and Akt activation in melanoma. As both pathways are believed to contribute to the chemotherapeutic resistance of melanoma cells, an effective treatment should target both ERK and Akt cascades. One potentially attractive target is the cytokine MIF (migration inhibition factor), since MIF can activate both the ERK and the Akt pathways. Targeting of MIF signalling in tumours producing autocrine MIF is already showing promise in prostate, breast and bladder cancers and although limited, some in vitro evidence suggests that MIF is an autocrine factor involved in the growth and invasion of melanoma cells. We have now extended these findings in an immunohistological study showing the universal in vivo expression of MIF in melanoma with increasing expression levels associated with metastatic tumours. MIF signalling can act through both CXCR4 and CD74/CD44 receptors, the latter molecule acting as a co-receptor. Examination of a panel of 20 melanoma cell lines showed 20/20 to express MIF and CD44 with 7/20 also co-expressing CD74. Only 6/20 cell lines showed heterogenous expression of CXCR4. Inhibition of MIF expression using siRNA-mediated gene knockdown decreased the proliferation and cell migration in a number of melanoma cell lines, an effect attributed to effects on cell cycle with a reduction of the number of cells entering S phase. Conversely, addition of exogenous MIF was shown to increase ERK phosphorylation. Taken together, these results suggest a role for MIF in melanoma progression. Future work will aim to determining the molecular nature of the receptors driving MIF signalling in melanoma.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1572.
Abstract 1576: Molecular targeting of histone deacetylase 2 for treatment of human hepatocellular carcinoma
Authors: Lee Yun-Han , Andersen Jesper B. , Judge Adam D. , Seo Daekwan , Marquardt Jens U. , Ishikawa Tsuyoshi , Avital Itzhak , Conner Elizabeth A. , MacLachlan Ian , Factor Valentina M. , Thorgeirsson Snorri S.
Published: February 2011

Development of targeted therapeutics for hepatocellular carcinoma (HCC) remains a major challenge. We have recently identified an elevated expression of histone deacetylase 2 (HDAC2) in primary human hepatocellular carcinoma (HCC) and HCC derived cell lines. In this study, we have tested if the downregulation of HDAC2 by siRNA can affect the course of HCC progression in vitro and in vivo. To inactivate HDAC2 gene expression, three HDAC2-specific siRNAs (HDAC2-1, HDAC2-2 and HDAC2-3) were designed and tested for growth inhibition in Huh7 and HepG2 HCC cell lines as determined by MTT assay, FACS analysis and microscopy. To obtain insights into molecular changes caused by HDAC2 silencing, global changes in gene expression were examined by illumina microarray. For in vivo evaluation of HDAC2 as a therapeutic target, we employed orthotopic xenograft model using luciferase-expressing HCC reporter cell line Huh7-luc+ and stable-nucleic-acid-lipid-particle (SNALP) as an optimal carrier of siRNA into liver.

The HDAC2-1siRNA was the most effective in inhibiting Huh7 and HepG2 cell growth (68% and 71%, respectively) which was paralleled by a similar decrease in the levels of target mRNA and protein. HDAC2-deficient cells also exhibited a 1.9-fold increase in apoptosis through activation of caspase-3. The comparison of gene expression profiles in HepG2 cells treated with either control siRNA or HDAC2-1siRNA identified 299 differentially expressed genes. Consistent with in vitro observations, genes functionally involved in apoptosis, such as CDKN1A, SOCS2, TP53I3, and BTG2, were up-regulated while genes associated with cellular metabolic process (e.g. HOXD1, PAK2, SMAD9, CDK4, PCK2 and SKP2) were down-regulated. HDAC2 3/7siRNA, a chemically modified variant of HDAC2-1siRNA displaying a minimal induction of IL-6 in murine Flt3L dendricite cultures, was selected for in vivo treatment of Huh7-luc+-derived HCC. Administration of SNALP- HDAC2 3/7siRNA effectively suppressed xenograft growth as compared to the SNALP-control siRNA treatment. Taken together, these results indicate that HDAC2 is an important regulator of HCC cell growth and survival, and may be an attractive target for systemic therapy of HCC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1576.
Abstract 1613: BTK as a drug target for cancers that harbor inactivating mutations in the DPC4 gene
Authors: Diep Caroline H. , Kassner Michelle , Zhao Yu , Yin Holly , Von Hoff Daniel D. , Han Haiyong
Published: February 2011

The Deleted in Pancreatic Cancer locus 4 (DPC4) is a tumor suppressor gene that is often inactivated in pancreatic and colorectal cancers. In pancreatic adenocarcinomas, the frequency of inactivation of DPC4 is approximately 55%, while in colorectal carcinomas has been reported to be 10% to 35%. The loss of DPC4 has been shown to be associated with the progression and malignancy of pancreatic cancer along with decreased patient survival. We employed a small interfering (siRNA) library based screening strategy to identify potential synthetic lethal partners of the DPC4 gene. We used a kinase focused siRNA library that consisted of two siRNA oligonucleotides for each of the 624 protein kinase genes. A DPC4 isogenic pair, BxPC3-Vector and BxPC3-DPC4 (Wang et al. 2006) were treated by the siRNA oligonucleotides in parallel and the effects of the siRNA oligonucleotides on the growth of the cell lines were then compared. siRNA oligonucleotides that selectively inhibited the cell growth of the BxPC3-Vector cell line were selected as potential positive hits. These genes, once validated, represented potential drug targets that are very specific to cancer cells harboring mutations in the DPC4 gene. One of the top-ranked hits we identified from this screening is the Bruton agammaglobulinemia tyrosine kinase (BTK). With BTK siRNA treatment, BxPC3-Vector cells, which are DPC4 null, showed ∼30% more cell growth inhibition than the BxPC3-DPC4 cells, which are DPC4 wildtype. This selectivity of BTK siRNA against DPC4 null cells was further confirmed in a confirmation screen using two pancreatic cancer cell lines, BxPC3 and PANC-1, which are DPC4 null and DPC4 wildtype, respectively. BTK siRNA also showed significant selectivity against DPC4 deficiency in another pair of DPC4 isogenic colon cancer cell lines, HCT-116 and HCT-116-DPC4-knockout. To validate the BTK siRNA selectivity findings, we evaluated the BTK inhibitor PCI-32765 in our cancer cell line models and observed the same selectively against DPC4 null pancreatic and colon cancer cell lines. These results indicate that BTK is a potential molecular target for pancreas, colon, and other cancers harboring inactivating mutations in the DPC4 gene. (The work was supported by a NCI grant P01CA109552.)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1613.
Abstract 1614: Guanylyl cyclase C signaling through vasodilator-stimulated phosphoprotein in lost in colon cancer
Authors: Pelta-Heller Josh , Zuzga David S. , Waldman Scott A. , Pitari Giovanni M.
Published: February 2011

The biochemical pathway(s) induced by guanylyl cyclase C (GCC) regulates the intestinal crypt-villus axis by modulating proliferation, maturation and metabolic programming. During colorectal tumorigenesis, GCC signaling through cGMP becomes dysregulated as a consequence of the reduced expression of GCC endogenous hormones guanylin and uroguanylin. However, the significance of the loss of ligand-dependent signaling by GCC for the human disease remains unclear. Here, immunohistochemical examination of tumor specimens from patients compared to respective normal adjacent tissues revealed that the GCC signaling through vasodilator-stimulated phosphoprotein (VASP), a key regulator of actin polymerization and morphogenetic dynamics, is lost in colon cancer. Interruption of GCC signaling through VASP resulted in tumor depletion of the cGMP-dependent VASP phosphorylation species, and presumably reflected complex alterations of the normal initiation and propagation of the ligand-induced GCC signal. In vitro reconstitution of the ligand-dependent GCC signal through VASP induced a functional remodeling of human cancer cells which assumed a rounded, lamellipodia-free morphology with reduced proliferative and invasive abilities. Importantly, GCC ligand therapy in vivo restored the cGMP-dependent VASP phosphorylation circuit in intestinal tumors of APCmin/+ mice. These findings offer a previously undescribed tumor suppressor mechanism, cGMP-dependent VASP phosphorylation, with high translational potential for the diagnosis and therapy of colon cancer. Reactivation of cGMP signaling through VASP by GCC hormone replacement therapy may represent an innovative paradigm for the treatment of colorectal cancer in patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1614.