bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 3737: The PI3K/mTOR inhibitor PWT33597 regresses 786-0 renal xenografts
Authors: O'Farrell Marie , Ventura Richard , Tai Albert , Matthews David J.
Published: August 2012

PWT33597 is a balanced dual inhibitor of phosphatidylinositol 3-kinase alpha (PI3K alpha) and mTOR, currently in clinical development. Inhibition of signaling downstream of PI3K and mTOR by PWT33597 has been demonstrated, and PWT33597 is strongly efficacious in multiple xenograft models tested to date with different PIK3CA and PTEN genotypes. Inhibitors of mTORC1 (rapalogs) are approved for treatment of advanced renal cell carcinoma (RCC), but their effect is restricted to a subset of patients, and is not sustained. Inhibitors of VEGFR signaling such as sorafenib and sunitinib have also demonstrated clinical activity in RCC and are approved in this indication. Based on the proven role of rapalogs in RCC, we tested PWT33597 in a renal xenograft model with the hypothesis that inhibition of both mTORC1 and mTORC2, as well as PI3K, may offer increased efficacy by direct targeting of multiple signaling nodes including VEGFR signaling. Dual inhibition would also be expected to decrease release of negative feedback loops triggered by either mTOR or PI3K inhibition alone. PWT33597 was tested in 786-0 (VHL -/-, PTEN -/-) xenografts in comparison to rapamycin (mTORC1 inhibitor), and sorafenib (VEGFR/RAF inhibitor). While sorafenib and rapamycin showed tumor growth inhibition (TGI), the maximal effect with sorafenib was 64% TGI, and rapamycin had a largely cytostatic effect. The overall efficacy observed with PWT33597 was superior, with 93% TGI observed. PWT33597 was also tested in comparison to a pan-PI3K inhibitor (GDC-0941, 49% TGI) and demonstrated superior efficacy. Immunohistochemical analysis of tumors for cleaved caspase 3 (CC3) as an indicator of apoptosis showed that a single dose of PWT33597 induced a several fold increase in CC3 staining, and this effect was also apparent after 18 days of dosing. Based on these results we tested the ability of PWT33597 to regress large 786-0 tumors (approx. 500 mm3), and a rapid decrease in tumor size was observed in 100% of animals. Additional cellular and xenograft studies in RCC models are ongoing to further define the mechanism of action of PWT33597, and will be presented. Taken together, these data provide rationale for testing PWT33597 in patients with RCC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3737. doi:1538-7445.AM2012-3737
Abstract 3749: Single agent activity of PIK3CA inhibitor BYL719 in a broad cancer cell line panel
Authors: Huang Alan , Fritsch Christine , Wilson Christopher , Reddy Anupama , Liu Manway , Lehar Joseph , Quadt Cornelia , Hofmann Francesco , Schlegel Robert
Published: August 2012

NVP-BYL719 is a p110α isoform-specific small molecule inhibitor that is currently in a Phase I clinical trial. To identify cancer populations that most likely to respond to BYL719 treatment, we initiated a comprehensive in vitro pharmacologic profiling screen across a large panel of cancer cell lines that have been previously characterized at the molecular level as part of the Cancer Cell Line Encyclopedia (CCLE) effort. We found that BYL719 responsive cell lines are enriched in indications such as Her2 positive and luminal breast cancer, while lacking in other indications such as Glioblastoma and Melanoma. Further exploration of the underlying genetic and pathway aberrations revealed that BYL719 sensitivity is positively associated with PIK3CA mutation, ERBB2 amplification and PIK3CA amplification/copy number gain. PTEN and BRAF mutations on the other hand, are associated with BYL719 insensitivities. KRAS mutation alone is neither associated with enhanced sensitivity nor insensitivity, however, co-commitant PIK3CA and KRAS mutants are more likely to be insensitive to BYL719 treatment. These findings will help to guide our clinical development plan.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3749. doi:1538-7445.AM2012-3749
Abstract 3750: The novel Akt inhibitor MK-2206, is cytotoxic in T-cell acute lymphoblastic leukemia: Therapeutic implications
Authors: Simioni Carolina , Cani Alice , Bressanin Daniela , Evangelisti Camilla , Chiarini Francesca , Capitani Silvano , Neri Luca M. , Martelli Alberto M.
Published: August 2012

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive neoplastic disorder arising within the thymus from the clonal proliferation of T-cell precursors. T-ALL accounts for 15% of ALL cases in children and 25% in adults. Although the prognosis of T-ALL has improved, due to the use of intensive polychemotherapy schemes, the outcome of relapsed and chemoresistant T-ALL is still poor, especially in adults, with a 35-40% survival at 5 years. Therefore, efforts are being made to develop targeted therapies against deregulated signaling cascades that sustain T-ALL cell proliferation, survival, and drug-resistance. A signaling pathway that is frequently upregulated in T-ALL, is the PI3K/Akt/mTOR network. To explore whether or not Akt could represent a potential target for therapeutic intervention in T-ALL, we evaluated the effects of the novel allosteric Akt inhibitor, MK-2206, on a panel of human T-ALL cell lines (MOLT-4, CEM, drug-resistant CEM) and primary cells from T-ALL patients, characterized by pathway upregulation. MK-2206 decreased T-ALL cell line viability as documented by MTT assays. IC50 for MK-2206 ranged from 1.0 to 4.8 μM at 48 hours. The drug was effective against drug-resistant CEM cells, overexpressing 170-kDa P-glycoprotein. MK-2206 blocked leukemic cells in the G1 phase of the cell cycle and induced caspase-dependent apoptotic cell death, as documented by Annexin V/propidium iodide staining and western blot analysis. In CEM cells, MK-2206 induced autophagy, as demonstrated by an increase in the 14-kDa form of LC3A/B. Western blotting documented a concentration-dependent dephosphorylation of Akt and its downstream targets, GSK-3β and FOXO3A, in response to MK-2206. mTORC1 downstream targets were also efficiently dephosphorylated by MK-2206, including p70S6K and 4E-BP1. MK-2206 decreased mTORC2 activity, as indicated by the downregulation of Ser 2481 p-mTOR levels, a readout for mTORC2 activity In MOLT-4 and CEM cells, MK-2206 strongly synergized (combination index: 0.1-0.33) with doxorubicin. Moreover, MK-2206 dephosphorylated Akt and induced apoptosis in a T-ALL patient cell subset (CD34+/CD4−/CD7−) which is enriched in leukemia initiating cells. Our findings indicate that Akt inhibition, either alone or in combination with chemotherapeutic drugs, represents a potential therapeutic target in T-ALL cells that require upregulation of the PI3K/Akt/mTOR signaling pathway for their proliferation and survival.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3750. doi:1538-7445.AM2012-3750
Abstract 3759: P7170, a novel inhibitor of phosphoinositide 3-kinase (PI3K)-mammalian target of Rapamycin (mTOR) and activin receptor-like kinase 1 (ALK1) as a new therapeutic option for Kras mutated non small cell lung cancer (NSCLC)
Authors: Agarwal Veena R. , Joshi Asavari , Venkataraman Magesh , Bhatia Dimple , Bose Julie , Kolla Lakshmi Sireesha , Gill Parkash , Sharma Somesh
Published: August 2012

Major breakthroughs in targeted cancer treatment have been achieved in last decade, but still some patient populations such as Kras mutated non small cell lung cancer (NSCLC), have no therapeutic options other than cytotoxic therapies. Therefore, development of targeted therapeutics is warranted in order to provide improved survival benefit for NSCLC patients with Kras mutation. P7170 is a small molecule inhibitor of PI3K (IC50 = 2.2 nM) and mTOR (IC50 = 4.4 nM). It also inhibits ALK1 and DNA-PK, two important enzymes involved in angiogenesis and DNA repair with IC50 of 47 and 1.5 nM, respectively. The structure, other in vitro, and in vivo efficacy of P7170 has been reported in the accompanying abstract submitted for AACR 2012. P7170 inhibited PI3K-mTOR pathway proteins pAKT, pS6 and p4EBP1 by 90 to 100 % in Kras mutated NSCLC cell line (H460) in a western blot assay. P7170 also exhibited potent cytotoxicity activity against two Kras mutated NSCLC (H460 and A549) cell lines with IC50 values of 7 and 5 nM. P7170 inhibited anchorage independent colony formation of tumor cells isolated from 10 different human tumor xenografts derived from NSCLC patient's tumors (Seven out of 10 samples had wild type Kras, and three had mutations in Kras). Moreover, P7170 induced apoptosis in H460 cell lines by inducing PARP cleavage. More interestingly, P7170 inhibited pAKT and pS6 in a dose dependent fashion in stem-like cells isolated from tumor samples of a Kras mutated NSCLC patient. P7170 demonstrated significant (p<0.01) in vivo efficacy following oral administration, in NSCLC xenograft studies using Kras mutated H460 cancer cell line. P7170 treatment resulted in 66% tumor growth inhibition at a dose of 5 mg/kg, and stabilization of tumor growth (89% tumor growth inhibition) at a dose of 20 mg/kg. Evaluation of mechanism of action of P7170 in H460 xenografted tumors confirmed the inhibition of PI3K-mTOR (pAKT and p4EBP) and Ras-Raf (pERK) pathways. In addition, inhibition of ALK1 and DNA-PK activity with the treatment of P7170 was also confirmed in xenografts. Conclusion: P7170 by virtue of its unique profile represents an opportunity to deliver a first-in-class therapeutic option for patients saddled with Kras mutated non small cell lung cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3759. doi:1538-7445.AM2012-3759
Abstract 376: Limits of [18F]-FLT PET as a predictive imaging biomarker of proliferation in oncology
Authors: McKinley Eliot T. , Ayers Gregory D. , Smith Ralph A. , Washington Mary K. , Coffey Robert J. , Manning Henry C.
Published: August 2012

Background: Surrogate, non-invasive imaging biomarkers of cellular proliferation hold great promise for quantifying response to personalized medicine in oncology. An emerging imaging approach to assess tumor proliferation utilizes the positron emission tomography (PET) tracer 3′-deoxy-3′[18F]-fluorothymidine, [18F]-FLT. Though several studies have associated serial changes in [18F]-FLT-PET with elements of therapeutic response, the degree to which [18F]-FLT uptake quantitatively reflects proliferative index has been continuously debated for more that a decade. The goal of this preclinical study was to elucidate quantitative relationships between [18F]-FLT-PET and cellular, proteomic, and genomic metrics proliferation in treatment naive tumors. Methods and Findings: [18F]-FLT-PET imaging was conducted in mice bearing human colorectal or breast cancer cell line xenografts. Quantitative relationships between PET imaging, thymidine kinase 1 (TK1) protein and RNA levels, and immunostaining for proliferation markers (Ki67, TK1) were evaluated using imaging-matched tumor specimens. Overall, we found that [18F]-FLT-PET reflects TK1 protein levels in tumors. However, the cell cycle specificity of TK1 expression and the variable degree to which tumors utilize thymidine salvage for DNA synthesis tend to decouple [18F]-FLT-PET data from estimates of proliferation by standard, clinically employed means. Conclusions: Our findings illustrate that [18F]-FLT-PET reflects tumor proliferation as a function of thymidine salvage pathway utilization. Therefore, unlike more generalizable proliferation markers, such as Ki67 immunostaining, tumor uptake of [18F]-FLT reflects proliferative indices to variable and potentially unreliable extents. [18F]-FLT-PET can not discriminate moderately proliferative, thymidine salvage driven disease from highly proliferative tumors that rely primarily upon de novo thymidine synthesis. For those reasons, the magnitude of [18F]-FLT uptake in treatment naive tumors should not be considered a surrogate of proliferative index. These data provide rationale for the diversity of correlative results reported, both positive and discordant, comparing [18F]-FLT-PET and tumor proliferation across numerous single-center clinical studies and provide a basis for future clinical best-practices when this imaging biomarker is employed in oncology.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 376. doi:1538-7445.AM2012-376
Abstract 3760: A novel PKC-iota inhibitor, ICA-1 abrogates cell proliferation in breast cancer
Authors: Desai Shraddha , Patel Rekha , McCray Andrea N. , Pillai Prajit , Acevedo-Duncan Mildred
Published: August 2012

The objective of this research was to identify the efficacy of [4-(5-amino-4-carbamoylimidazol-1-yl)-2,3-dihydroxycyclopentyl] methyl dihydrogen phosphate (ICA-1) as a novel PKC-iota inhibitor in breast cell proliferation. PKC-α is highly overexpressed in human breast cancer and is localized depending on the trend of pathologic type of the tumor [Hum Pathol. (2008) 6:824-831]; however, little is understood about its role in regulating cell proliferation in breast cancer. Results showed that PKC-α was highly activated and overexpressed in MD-MB-468 breast cancer cells. PKC-α directly associated and phosphorylated Cdk7, a master cell cycle regulator at T170 in a cell cycle dependent manner, phosphorylating its downstream target, cdk2 at T160. PKC-α co-localized with Cdk7 in nuclear and cytoplasmic region of MD-MB-468 cells. PKC-α downregulation reduced Cdk7 phosphorylation following ICA-1 (10µM) as well as PKC-α silencing (by siRNA treatment). PKC-α knockdown inhibited overall proliferation in breast cancer cells suggesting that breast cancer cells may be proliferating through a PKC-α/Cdk7/cdk2 mediated pathway. Hence, our results emphasize the potential of ICA-1 as a novel PKC-α inhibitor and chemotherapeutic agent for breast cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3760. doi:1538-7445.AM2012-3760
Abstract 3769: Metabolic activation of batracylin and N-acetylbatracylin to reactive metabolites that bind protein and DNA: Possible role in toxicity
Authors: Buhrow Sarah A. , Kuffel Mary , Walden Chad , Reid Joel M. , Covey Joseph , Ames Matthew M.
Published: August 2012

Batracylin (NSC 320846, BAT) is a heterocyclic arylamine and topoisomerase II inhibitor shown to be active in murine tumor models, but with demonstrated species differences in toxicity associated with metabolism to N-acetylbatracylin (NBAT) by N-acetyltransferase (NAT). BAT is a preferential substrate of human NAT2. Accordingly, production of NBAT should be subject to population variability as a function of NAT2 polymorphisms. A phase I clinical trial of BAT in patients with advanced cancer and slow acetylator NAT2 phenotypes to reduce the risk of NBAT-related toxicity found a dose-limiting toxicity (DLT) of cystitis/hemorrhagic cystitis. In subsequent in vitro and in vivo preclinical studies to elucidate metabolic pathways that might contribute to BAT toxicity, we found oxidative metabolites and thiol conjugates of BAT and NBAT (MM Ames et al, Cancer Res 2011;71(8 Suppl):Abstract nr 1303). Since these data are consistent with metabolic activation of BAT to potentially toxic metabolites, we assessed formation of reactive intermediates as measured by covalent binding (CB) to protein and DNA or by formation of glutathione conjugates. Radiolabeled BAT and NBAT were incubated with 3-MC-induced rat (r), human (h) and dog (d) liver microsomes (LM), as well as with recombinant human cytochromes P450 (CYPs) with or without added DNA. NADPH-dependent BAT protein and DNA CB were detected in all microsomal preparations (see table below). NADPH-dependent NBAT protein CB was detected in all microsomal preparations except hCYP1B1. NADPH-dependent NBAT DNA CB was detected in all microsomal preparations except 3MC-rLM. We also detected a glutathione conjugate of mono-hydroxy BAT by lc/ms/ms analysis when BAT was incubated with hLM in the presence of glutathione and NADPH. Thus, CYP-catalyzed oxidation of BAT yields reactive metabolites that that bind protein and DNA and may contribute to drug-related DLT. Supported in part by NCI Contract N01-CM-52206.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3769. doi:1538-7445.AM2012-3769
Abstract 3793: Characterization of the mechanism of action of a novel small molecule inhibitor of HSP70
Authors: Balaburski Gregor , Leu Julia I-Ju , Andrake Mark , Hayik Seth , Beeharry Neil , Dunbrack Roland , Yen Tim , George Donna L. , Murphy Maureen E.
Published: August 2012

The stress-induced heat shock protein HSP70 is an ATP dependent molecular chaperone that plays a role in the folding of nascent peptides, assembly of multi-protein complexes, and transport of proteins across membranes and overall. Additionally, HSP70 has significant cytoprotective and anti-apoptotic functions. High levels of HSP70 can be found in many cancers, and are associated with poor therapeutic response and poor patient prognosis. These findings suggest that HSP70 may be a desirable molecular therapeutic target, in addition to being a useful tumor prognostic marker. Previously we demonstrated that the compound 2-phenylethynesulfonamide (PES) interacts with HSP70 and antagonizes HSP70 function by disrupting the interaction between HSP70 and its co-chaperones and client proteins. We showed that PES is toxic to cancer cells but not non-transformed cells. Moreover, PES was able to significantly extend the lifespan of mice in a Myc-driven model of lymphoma (p<0.02; Leu et al., Mol Cell 36:15-27, 2009; Leu et al, Mol Can Res 9:936-47, 2011). Here we utilized binding assays, molecular modeling and in silico docking in order to predict the binding site for PES with HSP70. We were able to verify this binding site by identifying point mutants of HSP70 that fail to bind to PES. We used this information in order to predict potentially superior analogues, and we report that a novel analogue, 2-(3-chlorophenyl) ethynesulfonamide (PES-Cl) shows superior toxicity to tumor cells, and greater efficacy as an anti-cancer agent in Myc-driven lymphoma, compared to the parent compound (p<0.0006). Moreover, we report that treatment with PES-Cl causes cell cycle arrest in G2/M, and that a significant fraction of tumor cells escape this checkpoint and die by apoptosis. These data implicate HSP70 in G2/M progression, and identify PES-Cl as a promising anti-cancer therapeutic.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3793. doi:1538-7445.AM2012-3793
Abstract 3801: Prostate cancer cells are selectively targeted by zinc-sequestration chemotherapy
Authors: Dambal Shweta K. , Mihelich Brittany , Hergenrother Paul , Nonn Larisa
Published: August 2012

Introduction: Zinc accumulates at levels 10-fold higher in the prostate than other soft tissues and this metal is implicated in prostate cancer (PCa) pathogenesis. Prostatic lesions have 6-fold lower concentrations of zinc than normal adjacent prostate tissue. Zinc levels are even lower in normal and malignant prostate tissue from African American (AA) men, who are 1.5 times more likely to develop prostate cancer than their Caucasian (Cauc) counterparts, thus highlighting the associative that that zinc could have in prostate cancer carcinogenesis. PAC-1 is a chemotherapeutic agent that induces cell death via zinc sequestration by activation of pro-caspase 3, which is a major player in cell death. We hypothesized that the low zinc levels in prostate cancer cells will cause the cells to be uniquely sensitive to cell death by PAC-1. Secondarily we hypothesized that AA patients, who have lower zinc in the prostate, may have enhanced response to PAC-1. Methods: PAC-1 cytotoxicity was investigated in LNCaP, PC-3, 957e/hTERT (immortalized normal primary cell line) and patient-derived normal and cancer primary epithelial cells (PrE) by treatment with 100, 50, 25,10,1, 0 micromolar concentrations of PAC-1 and PAC-1 analogs. Cell death was analyzed via the MTS colorimetric assay. Results and conclusion: Normal and cancer prostate cells are sensitive to PAC-1 and even more sensitive to PAC-1 analogs. PAC-1 was growth inhibitory and induced cell death at higher concentrations. Ongoing studies will examine zinc-dependency of PAC-1-induced death. PAC-1 and its analogs-induced cell death and caspase-3 activation will be measured in zinc-depleted, zinc sufficient and zinc-excess media. Studies will also determine PAC-1 cytotoxicity in normal and cancer prostatic epithelial cells. PAC-1 cytotoxicity levels in patient-matched prostate cancer cells (PrCa) from AA and Cauc men will also be studied to interrogate the disparate role of zinc in regards to sensitivity to PAC-1. These results may be translated to the clinic since a derivative of PAC-1 (S-PAC-1) has been shown to have positive effects in a Phase I clinical trial in pet dogs with lymphoma.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3801. doi:1538-7445.AM2012-3801
Abstract 3803: Anti-cancer activity of Capridine, a novel nitroacridine chemotherapeutic, in glioblastoma
Authors: Shanmugam Arulkumaran , Rajoria Shilpi , George Andrea L. , Jussim Casey , Suriano Robert , Konopa Jerzy , Mittelman Abraham , Tiwari Raj K.
Published: August 2012

Glioblastoma is characterized by highly proliferative tumor cells, increased cellularity, necrosis, and proliferation of capillary endothelial cells. The incidence rate of glioma in adults is 50% greater in men than in women suggesting that there may be a male hormonal component that modulates glioblastoma progression. Our preclinical developmental program identified Capridine as a chemotherapeutic agent that had specificity towards prostate cancer with minimal bone marrow toxicity. Since the DNA intercalating activity of Capridine does not completely correlate with its cytotoxic activity, we examined other alternative cellular targets. Our investigation identified the androgen receptor (AR) and its dependent signal transduction mechanism as a possible cellular mediator of its cytotoxic activity. In this study, our analysis revealed that glioblastoma cell lines T98G and MO59K expressed AR and their growth was responsive to the AR-mediated signal transduction. Capridine inhibited the growth of glioblastoma cells by down regulating the AR and inhibiting the phosphorylation of Focal adhesion kinase (FAK). Since FAK is associated with integrin and neuropeptide mediated signaling, critical for cell migration and invasion, we examined the activity of Capridine on cell invasion and migration using a Boyden Chamber assay. Capridine inhibited the migration and invasion of the glioblastoma cell lines T98G and MO59K. Our data not only validate AR as a target of Capridine as with prostate cancer but also implicate a novel target, FAK in glioblastoma. Combination approaches using Capridine and anti-hormonal therapy may prove to be viable chemotherapeutic regimen for primary glioblastoma as well as an inhibitor of metastatic propensity. These preclinical studies are being extended in an in vivo animal model with combination treatment approaches with a view to develop novel chemotherapy based treatment for glioblastoma.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3803. doi:1538-7445.AM2012-3803
Abstract 3805: Identification of a distinctive pattern of lipid composition in Irvalec® resistant tumor cells
Authors: Molina-Guijarro José M. , Moneo Victoria , Martínez-Leal Juan F. , Fernández-Rodríguez Rogelio , Cuevas Carmen , Garcia-Fernandez Luis F. , Galmarini Carlos M.
Published: August 2012

Irvalec® is a marine derived synthetic depsipeptide showing cytotoxic activity against a wide diversity of tumor cells both in vitro and in vivo. The compound is currently undergoing Phase II clinical studies in patients with solid tumors. The existing data on the mechanism of action of Irvalec® indicate that the compound inserts and self-organize in the plasma membrane of tumor cells, rapidly inducing loss of membrane integrity and cell permeabilization, giving rise to a fast and dramatic necrotic death. By continuous exposure of human colon carcinoma HCT-116 cells to stepwise increasing concentratrions of Irvalec®, a resistant subclone of the cell line was established, named HCT-116-Irv. In dose-response cytotoxicity assays, HCT-116-Irv cells showed a GI50 value >50 μM, representing a specific resistance index to the compound greater than 10.8 as compared to their wt counterpart. The resistant cells did not show any of the morphological and physiological responses to Irvalec® observed in parental cells and no overexpression of Pgp efflux pump or significant cross-resistance to other antitumoral drugs was detected. Due to the presumably direct effect of Irvalec® on the cell membrane, we searched for possible changes in the lipid composition of the resistant cells, acquired during the process of resistance development. After fractionation of the lipid extracts using thin layer cromatography (TLC), two differential fractions, that were completely absent in the resistant cells as compared to wt cells, were identified and purified. Interestingly, one of these fractions, named F4, was found to be able to interact with a biotinilated derivative of Irvalec®, using a standard overlay assay. These results suggested that the lipid composition could be directly related to the sensitivity of tumor cells to Irvalec®. Efforts are now focused on the chemical characterization of the selected lipid fraction and its putative biological role mediating the cytotoxic response to Irvalec®.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3805. doi:1538-7445.AM2012-3805
Abstract 3812: Deguelin as a novel therapeutic agent for Herceptin resistant breast cancers
Authors: Mehta Rajeshwari , Alimirah Fatouma , Gupta Akash , Kalra Amit , Mehta Rajendra
Published: August 2012

Human breast cancers overexpressing HER-2 are generally highly aggressive. Current therapeutic strategies to target HER-2 signaling pathway with antibodies or small molecule tyrosine kinase inhibitors have shown impressive success in the management of these tumor types, although most women exhibit short term response to these therapies. Acquired resistance to HER-2 target drugs, especially Herceptin is a major challenge to clinicians. Patients receiving Herceptin therapy invariably recur and most often with highly aggressive tumors. Thus identifying new drugs which target multiple molecular pathways is desired to treat Herceptin resistant breast cancer. Using paired HER-2 overexpressing parental Herceptin responsive (BT-474) and its Herceptin resistant variant cells (BT-474HR) we showed that acquired resistance to Herceptin is associated with enhanced expression of HER-2, EGFR, CyclinD1, P-AKT (Ser-473), PI-3K, JAB1 proteins and decreased expression of nuclear pten and p27 proteins. These results are similar to those observed in recurrent breast tumors in patients following Herceptin treatment. Deguelin, a natural product derivative of rotenoids and has been shown to inhibit growth of diverse cancer types. Deguelin is a known AKT inhibitor, however its efficacy is never tested in breast cancers resistant to Herceptin which express high levels of p-AKT. We examined effect of Deguelin on HER-2 overexpressing BT-474 BT-474-HRcells. Deguelin inhibited growth of both, BT-474 and BT-474HR cells in concentration (0-250nM) and time dependent (24-72h) manner. There was a 40-50%- inhibition of both BT474and BT-474HR cells at 25nM Deguelin treatment at 72h. Deguelin decreased cell surface expression of HER-2 in both these cell lines. In parental BT-474 cells both Herceptin 5-10ug/ml and Deguelin down regulated HER-2 expression, but only Deguelin reduced HER-2 (125-250nM) over expression in both BT-474 and BT-474HR cells. Down regulation of HER-2 following Deguelin treatment was associated with simultaneous down regulation of nuclear accumulation of cyclin D1, and JAB1, and p-AKT (Ser-473) proteins and up regulation of nuclear p27 and p53in both BT-474 and BT474 HR cells. These results suggest that Deguelin inhibits growth of both HER-2 overexpressing and those resistant to Herceptin therapy breast cancer cells. Effect of Deguelin appears to be mediated through down regulation of HER-2, PI3K AKT, JAB1, Cyclin D1, and p27 pathway. Our preliminary results warrant further investigation into Deguelin as a potential therapeutic agent for Herceptin resistant breast cancers. (This work was supported by NCI CA140321.)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3812. doi:1538-7445.AM2012-3812
Abstract 3814: Combination of selective modular of the glucocorticoid receptor (SEGRA) with proteasome inhibitors as a novel strategy for chemotherapy of hematologic malignancies
Authors: Yakubovskaya Marianna G. , Lesovaya Ekaterina A. , Yemelyanov Alexander , Kirsanov Kirill I. , Budunova Irina
Published: August 2012

Glucocorticoids are widely used for the treatment of hematological malignancies; however chronic treatment with steroids results in numerous adverse effects. Glucocorticoid receptor (GR) regulates gene expression via transactivation that requires GR homodimer binding to gene promoters; and transrepression mediated via negative interaction between GR and other transcription factors. GR transactivation is linked to metabolic side effects, while GR transrepression underlies glucocorticoid therapeutic action. One of the novel GR modulators is 2-(4-acetoxyphenyl)-2-chloro-N-methylethylammonium-chloride also called CpdA. CpdA is a synthetic analogue of a aziridine precursor isolated from the Namibian shrub Salsola tuberculatiformis Botschantzev. Using representative human T cell (CEM) and B cell (NCEB) lymphoma cell lines expressing functional GR, and their counterparts with blocked GR expression, we showed that CpdA indeed acted as dissociated GR ligand, and inhibited growth and survival of these cells via GR. Sensitivity to therapeutic effects of GCs directly depends on the amount of functional GR. The 26S protesome controls GR protein stability, and is responsible for desensitization to GCs via hormone-induced GR degradation and following development of glucocorticoid resistance in patients. Thus, the use of proteasome inhibitors represents a pharmacological approach to prevent GR down-regulation and to elevate the level of GR in cells. Proteasome inhibitor Bortezomib (BZ) was approved by FDA for the treatment of patients with multiple myeloma and mantle cell lymphoma. Since proteasome inhibitors stabilize GR, we hypothesized that BZ will augment CpdA effects as a selective GR modulator and enhance its chemotherapeutic activity. We showed that pretreatment of CEM and NCEB cells with proteasome inhibitor Bortezomib resulted in GR accumulation, and enhanced CpdA ligand properties further shifting GR activity towards transrepression evaluated by inhibiton of NF-kB and AP-1 factors. We also revealed remarkable GR-dependent synergy between CpdA and BZ in suppressing growth and survival of T and B lymphoma cells. Overall, our data provide the rationale for novel GR-based therapy for lymphoma and leukemia based on the combination of non-steroidal GR modulators with proteasome inhibitors.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3814. doi:1538-7445.AM2012-3814
Abstract 3818: Arsenic hexaoxide (As4O6) shows anticancer effects on human colon cancer cells in vitro and in vivo
Authors: Yun Jeong Won , Lee Won Sup , jeong Kim Min , Lu Jing Nan , Kim Dong Chul , Choi Yung Hyun , Jeong Jae-Hoon , Kim GonSup
Published: August 2012

Arsenic hexaoxide (As4O6) has been used as a folk remedy for the treatment of cancer since the late 1980's in Korea, and evidence suggests that As4O6-induced cell death pathway was different from that of As2O3. Here, we investigated the anticancer activities of As4O6 on SW620 human colon cancer cells. As4O6 induced cell death in a dose-dependent manner. The cell death was caspase-independent. In addition, the apoptosis was associated with suppression of p-Akt and activation of p-P38. As4O6 suppressed TNF-induced NF-κB activation through suppression of phosphorylation of IαB. As4O6 also suppressed NF-κB-regulated genes (Bcl-2, XIAP, and Bcl-xL) which are involved in anti-apoptosis. In animal experiments, As4O6 inhibited tumorigenicity of SW620 cells in a xenograft mouse model without showing any harmful effects on mice. As4O6 significantly inhibited intratumoral microvessel density. However, the inhibitory effects of As4O6 on NF-κB was minimal. In summary, in vitro study indicates that the As4O6 have anti-cancer effects on SW620 human colon cancer cells through inducing apoptosis by inhibiting anti-apoptotic molecules and in vivo study suggested that As4O6 should have additional anti-angiogenic activity. This study provides the evidence that As4O6 might be useful in the treatment of human colon cancer. [This study was supported by a grant from the National R&D Program for Cancer Control, Ministry for Health, Welfare & Family Affairs, Republic of Korea (0820050), and National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (No. 2011-0007389)]

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3818. doi:1538-7445.AM2012-3818
Abstract 3834: JKA97, a novel anti-cancer candidate, induces G1 arrest via up-regulation of p21 in a p53-independent manner
Authors: Wang Wei , Yang Xinyi , Zhang Xu , Wang Ming-hai , Sharma Horrick , Buolamwini John K. , Zhang Ruiwen
Published: August 2012

Breast cancer is one of the most commonly diagnosed cancers and the leading causes of cancer death in women worldwide. Natural product-oriented synthetic derivatives have played an important role in cancer drug discovery. JKA97, a benzylidene analog of harmine, is a novel anti-cancer candidate. The initial studies have shown its inhibitory effects on tumor growth in experimental models. However, the underlying molecular mechanisms are not fully elucidated. In this study, we determined the anti-cancer effects of JKA97 on human breast cancer in vitro and in vivo. Our data showed that, in a dose-dependent manner, JKA97 efficiently inhibited the growth and proliferation of human breast cancer cells with different p53 status, including MCF7 (p53 wild-type), MCF7 (p53 knockdown) and MDA-MB-468 (p53 mutant) cells. We also found that JKA97 induced apoptosis in human breast cancer cells independent of p53 and that JKA97 treatment resulted in G1 phase arrest in all the three breast cancer cell lines. In vivo, JKA97 significantly suppressed the growth of both breast cancer MCF7 and MDA-MB-468 xenograft tumors. Mechanistically, JKA97 modulated the levels of various cell-cycle regulators involved in G1 to S phase progression, such as p21, p27, cyclinE, and cyclinD1. Our results indicated that p21 and p27were up-regulated while cyclinE and cyclinD1 were down-regulated by JKA97 treatment. Using quantitative PCR and luciferase reporter assays, we demonstrated that the major mechanism for G1 phase arrest by JKA97 was induction of p21 at the transcriptional level, independent of p53. We further confirmed the role of p21 in JKA97-induced G1 phase arrest by using HCT116 cells with or without p21 expression. Taken together, these findings suggest that JKA97 inhibits human breast cancer by inducing cell cycle arrest through up-regulation of p21, regardless of p53 status. Considering that more than 50% human cancers have no or mutant p53 expression, our results provide a basis for further development of this compound as potential drug for breast cancer therapy. (This work was supported in part by NIH/NCI grants R01 CA112029 and R01 CA121211, R15 CA100102 and a grant (BCTR070731) from Susan G Komen for the Cure.)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3834. doi:1538-7445.AM2012-3834
Abstract 3975: Detecting patient mutomes by integrating DNA and RNA sequencing
Authors: Wilkerson Matthew D. , Sun Wei , Wang Kai , Cabanski Christopher R. , Hoadley Katherine A. , Liu Jinze , Prins Jan , Hayes D Neil
Published: August 2012

Personalized cancer medicine, the matching of therapies to a given patient's somatic alterations, depends on highly accurate and complete identification of patients’ somatic alterations, or their mutome. Advances in sequencing technologies (exome sequencing, RNAseq, and whole genome sequencing) have provided a means to examine large portions of the genetic content of patients’ cancers. Computational tools have arisen that make somatic mutation predictions utilizing particular sequencing assays; however, each sequencing assay has limitations and existing mutation detection tools exhibit less than ideal agreement when analyzing the same data. The task of identifying all somatic mutations in one patient's cancer remains a challenge to personalized cancer medicine. Typically, somatic mutation detection is performed utilizing DNA sequencing. Because RNA sequencing is often a component of genome characterization projects along with DNA sequencing, we sought to evaluate the possible added value of RNA sequencing in somatic mutation detection. We have developed an original computational method, UNCeqR, that makes patient-specific somatic mutation predictions utilizing RNA sequencing combined with DNA sequencing. DNA mutations and RNA mutations are statistically modeled separately and results are combined in a meta-analytic fashion, resulting in up to three predictions for a locus: DNA-only, RNA-only, and DNA+RNA. In addition to de novo genomewide mutation predictions, UNCeqR can query specific a priori mutations. UNCeqR was applied to The Cancer Genome Atlas (TCGA) lung squamous cell carcinoma sequencing data, consisting of Ilumina RNAseq and Illumina exome sequencing. Of annotated exons, 20% had very low to zero coverage in RNA and 5% had very low to zero coverage in DNA, indicating that both sequencing assays add new genomic territory for mutation detection. Limiting to regions with both DNA and RNA coverage, 56% of mutations detected from DNA were also predicted by RNA, providing an independent validation of these mutations. To evaluate if mutation detection using DNA+RNA is superior to detection using DNA-only, cancer specimen DNA and RNA reads were randomly split into subsamples. UNCeqR was executed on each of the subsamples and mutation agreement was compared among pairs of subsamples within regions of DNA and RNA coverage. Compared with the DNA-only method, DNA+RNA mutation detection exhibited a 42% relative increase in percent agreement across subsamples and a 230% relative increase in the number of mutations detected. Therefore, RNA sequencing adds positive value to somatic mutation detection via UNCeqR.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3975. doi:1538-7445.AM2012-3975
Abstract 3977: Meta-analysis of posttranslational modifications in cancer
Authors: Hornbeck Peter V.
Published: August 2012

PhosphoSitePlus (http://www.phosposite.org) is a comprehensive and easy-to-use resource that includes aggregated information about experimentally observed post-translational modifications (PTMs) observed in over thirty distinct types of cancer. Most of the cancer data is derived from over 900 mass spectrometric datasets of human disease tissues or cell lines, either reported in the literature or from studies performed at Cell Signaling Technology. The four most highly represented diseases are non-small cell lung carcinoma (269 datasets and over 5500 unique sites), breast cancers (99 datasets with over 2630 sites), acute myelogenous leukemia (70 datasets with over 1860 sites), and chronic myelogenous leukemia (115 datasets with over 1700 sites). Users can extract datasets associated with specific diseases, and analyze the data a number of newly-developed analytical tools. These include motif-analysis, permitting users to determine if specific kinases appear to be active in different diseases, and pathway analysis using novel Cytoscape plugins. Datasets and Cytoscape pathways corresponding to specific diseases and other data subsets can be downloaded from the site, enabling users to apply their own bioinformatics analyses to the information available at PhosphoSitePlus.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3977. doi:1538-7445.AM2012-3977
Abstract 3982: Cancer genome sequencing analysis, storage, discovery and delivery
Authors: Sanborn John Z. , Vaske Charles J. , Benz Stephen C.
Published: August 2012

Genome instability and structural rearrangement is a distinctive hallmark of the cancer genome. With next-gen sequencing technologies, our ability to measure structural rearrangements that occur throughout tumorigenesis and progression has improved significantly, while creating an urgent need for rearrangement discovery, analysis, and visualization methods to aid in our understanding of these events. We have developed a sequencing analysis pipeline that streamlines the discovery of an individual tumor's mutations, small indels, copy number alterations, allele-specific amplifications and deletions, and genomic rearrangements. Rearrangements are refined to base-pair precision using unmapped, putative split reads found in the vicinity of the breakpoint. Results are presented in an interactive, web-based genome browser that provides analysis and visualization of both high-level, processed results as well as the raw data from which they were derived. From the web-based interface, results from multiple samples can be aggregated into user-defined sample cohorts to help identify features that are shared among a significant number of the samples. Using this sequencing analysis pipeline, we discovered high-confident, small- and large-scale somatic events in 17 whole genome glioblastoma multiforme (GBM) tumor samples from The Cancer Genome Atlas (TCGA) project, using their matched normal sequences to filter out germline variants. Among many interesting structural aberrations identified in these samples, we find four samples exhibiting EGFR amplifications and the presence of the EGFRvIII mutant, characterized by the in-frame deletion of exons 2-7 to produce a constitutively active form of the receptor. Comparing the read support of the EGFRvIII-associated breakpoints to the number of normally-mapped reads in the neighborhood suggest that, in all cases, the EGFRvIII mutant emerges after the amplification of wild-type EGFR, existing as a small fraction of total number of EGFR copies. In other samples, evidence of high copy number amplicons containing both MDM2 and EGFR are discovered at detectable levels in the blood sequencing data, raising the possibility that patient-specific PCR-based assays could be developed to quantitate the presence of somatic rearrangements as a proxy to monitor the progression of brain tumors.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3982. doi:1538-7445.AM2012-3982
Abstract 3983: Evaluation of data compression strategies for genetic variation calling using next generation sequencing data in normal and tumor samples
Authors: Xiao Chunlin , Yaschenko Eugene , Kimelman Mikhail , Rodarmer Kurt , Sherry Stephen
Published: August 2012

The per-base cost of whole genome sequencing has dropped dramatically due to recent advancement of next generation sequencing (NGS) technologies, and a number of large-scale re-sequencing projects, e.g. 1000 Genomes, ICGC, TCGA, GO-ESP, and CGCI etc., have been initiated to extend our knowledge of single nucleotide polymorphisms (SNPs), short insertions/deletions (INDELs) and structural variations (SVs), and relate these variants to human diseases. To date, various compression technologies, including NCBI's cSRA and EBI's CRAM etc., have been developed to significantly reduce the storage footprints and costs. However, whether or not such compression treatments have any impact on genetic variant callings has not been systematically assessed and validated with large scale NGS datasets as different calling algorithms for different variant classes (SNPs, INDELs, or SVs) may have different underlying data requirements. We have developed an integrated analysis framework (VarPipe) to profile genetic mutations using NGS data generated from various sequencing platforms in a uniform manner. This pipeline is also applied to the official data from 1000Genomes (normal samples) and Cancer Genome Characterization Initiative (tumor samples) projects to evaluate the compressions effects on variation callers. With defined quality metrics, the variant callsets from compression-treated and untreated data are carefully evaluated as well as compared to the official variation releases of the corresponding projects so that optimal compression strategy can be developed and recommended for variation detection using NGS data.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3983. doi:1538-7445.AM2012-3983