bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 5338: A repressive EWS-FLI1 subsignature is the result of FOXO1 suppression and nuclear exclusion
Authors: Niedan Stephan , Kauer Maximilian , Jug Gunhild , Walker Robert L. , Meltzer Paul S. , Kovar Heinrich
Published: June 2012

The EWS-FLI1 chimeric protein, characteristic of Ewing′s sarcoma (ESFT), constitutes the prototype of an aberrant oncogenic ETS transcription factor. The mechanisms of transcriptional regulation leading to ETS-driven tumorigenesis are poorly understood. In-silico analysis of time-resolved expression data revealed enrichment of ETS binding motifs in EWS-FLI1 activated target promoters, while EWS-FLI1 repressed promoters showed most prominently enrichment of recognition motifs for forkhead box (FOX) proteins. Several FOX genes were found to be bound by EWS-FLI1 in ChIP-seq and transcriptionally affected by EWS-FLI1 knockdown. We therefore hypothesized that EWS-FLI1 exerts an important part of its repressive activity via inhibition of FOX proteins. Upon silencing of EWS-FLI1, both FOXO1 and FOXO3 proteins were strongly induced in ESFT cells consistent with this hypothesis, but only FOXO1 translocated to the nucleus. However, in the presence of EWS-FLI1, ectopic FOXO1 was found excluded from the nucleus as consequence of phosphorylation. Nuclear translocation was restored by either inhibition of CDK2, a directly EWS-FLI1 activated kinase, augmented by chemical inhibition of PI3K, or by mutation of CDK2 phosphorylation sites. These results suggest an important role for CDK2 in FOXO1 repression by EWS-FLI1. To test the contribution of FOXO1 to the EWS-FLI1 repressive signature on the ESFT transcriptome, the overlap between genes activated by EWS-FLI1 knockdown and genes activated by ectopically expressed, nuclear directed FOXO1 was determined and compared to the effects of EWS-FLI1 knockdown under concomitant FOXO1 silencing. A significant overlap between FOXO1 activated and EWS-FLI1 repressed genes was identified (P<10e-20, hypergeometric test). Taken together, these data confirm our hypothesis that a repressive subsignature of EWS-FLI1 regulated genes is due to suppression of FOXO1. Functional restoration of nuclear FOXO1 expression in ESFT cells resulted in impaired proliferation and significantly reduced soft agar colony formation ability suggesting that FOXO1 plays an important role in ESFT oncogenesis.

This study was supported by grant 22328-B09 from the Austrian Science Fund FWF.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5338. doi:10.1158/1538-7445.AM2011-5338
Abstract 5375: Reestablishing cell cycle control in breast cancers through therapeutic CDK4/6 inhibition
Authors: Dean Jeffry L. , Thangavel Chellappagounder , McClendon A. Kathleen , Ertel Adam , Knudsen Erik S.
Published: June 2012

One hallmark of cancer is the deregulation of cell cycle machinery, which ultimately serves to promote aberrant proliferation that fuels tumorigenesis and progression. Particularly, the cyclin D1/Rb/E2F axis plays a crucial role in the development of disease by serving to connect aberrant mitogenic signaling with cell cycle transcriptional programs. In this context, the role of estrogen receptor (ER) in breast cancers has been previously described to exert influence upstream of this axis. While first-line strategies targeting ER activity are prevalent and initially effective in the majority of ER-positive breast cancers, acquired resistance and therapeutic failure remain a major clinical challenge. Current analyses have revealed that cell cycle progression is effectively uncoupled from the activity and functional state of ER in these models. As a gene expression signature of cyclin D/Rb/E2F-dysfunction was found to be associated with luminal B breast cancers (which are known to exhibit a relatively poor response to endocrine therapy), the prevalence of ER dysfunction occurring upstream of cyclin D1 suggests that targeting CDK 4/6 activity may be effective. To this end, we examined the therapeutic response to a CDK 4/6 inhibitor (PD-0332991) in human breast cancer cell lines and demonstrated a highly-specific role for Rb in mediating this response, which was dependent on transcriptional repression manifest through E2F activity. These analyses additionally demonstrated that the chronic loss of Rb can promote evolution to a CDK4/6-independent state and near complete resistance to PD-0332991. In addition to these studies, model systems of ER-positive breast cancers with differential susceptibility to endocrine therapy were employed to define common nodes for new therapeutic interventions. These collective findings suggest that suppression of cyclin D-supported kinase activity and restoration of Rb-mediated transcriptional repression could represent a viable therapeutic option in tumors that fail to respond to hormone-based therapies. Consistent with this hypothesis, CDK4/6 inhibiton was effective at suppressing the proliferation of all hormone refractory models analyzed. Combined, these findings underscore the clinical utility of mediating aberrant cell cycle progression through down-stream cytostatic therapies in treating tumors that have experienced failure of first line and endocrine-based therapy, and provide rationale for incorporation of CDK 4/6 inhibition into current existing therapeutic regimens.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5375. doi:10.1158/1538-7445.AM2011-5375
Abstract 5379: Ciclopirox induces autophagy through reactive oxygen species-mediated inhibition of mTOR signaling pathway
Authors: Zhou Hongyu , Huang Shile
Published: June 2012

Ciclopirox olamine (CPX), a synthetic antifungal agent clinically used to treat mycoses of the skin and nails, has been recently found to inhibit tumor growth in mouse model of leukemia and breast cancer MDA-MB231. The mammalian target of rapamycin (mTOR), an evolutionarily conserved serine/threonine kinase, is known as a negative regulator of autophagy. Herein, we found that CPX substantially increased GFP-LC3 dots and expression of LC3-II, a hallmark of autophagy, suggesting that CPX induced autophagy. Meanwhile, we discovered that CPX inhibited mTOR signaling in different cancer cell lines, as evidenced by reduced phosphorylation of the downstream targets of mTOR, p70 S6 kinase 1 (S6K1) and eukaryotic initiation factor 4E (eIF4E) binding protein 1 (4E-BP1). Recently, it has been demonstrated that autophagy can be induced by reactive oxygen species (ROS). Interestingly, we further found that CPX treatment dose-dependently induced ROS generation. Pretreatment with N-acetyl-L-cysteine (NAC) suppressed CPX-induced ROS and the conversion of LC3I to LC3II, suggesting that CPX-induced autophagy is mediated by ROS generation. Moreover, the inhibition of phosphorylation of S6K1 and 4E-BP1 by CPX were partially rescued by NAC pretreatment as well. These data suggest that CPX-induced autophagy may be attributed to induction of ROS and subsequent inhibition of mTOR signaling.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5379. doi:10.1158/1538-7445.AM2011-5379
Abstract 5384: Amonafide demonstrates a clearly differentiated chemoresistance and chemosensitivity profile when compared to classical TopoII inhibitors
Authors: Green Colin F. , Chau MyDoanh , Christensen Jennifer , Ajami Alfred
Published: June 2012

Background: Amonafide is a novel DNA intercalator that induces apoptosis by mechanisms involving Topo II. Previous pharmacogenomic studies have shown differences between amonafide and classical TopoII inhibitors. Here data from publicly available gene expression studies have been analyzed to determine the chemoresistance and chemosensitivity profiles of amonafide compared to other agents.

Methods: Data were mined from the Stanford, MIT-Broad and NCI databases. A subset of genes associated with drug efflux, chemo-sensitivity & -resistance was selected from the array data. Effects on gene expression were assessed by determining Pearson correlation coefficients (PCC) for gene-drug pairs.

Results: For drug efflux genes & 15 genes associated with cell regulation, amonafide, and 5-azacytidine (azaC) had a positive correlation between expression & cytotoxicity; doxorubicin (Dox), and daunorubicin (Dnr) showed a negative correlation; cytarabine (araC) was unaffected. The chemo-sensitivity and -resistance profiles were determined by identifying the 15 genes with the highest correlation for each of the 5 drugs vs the other 4. Amonafide & aza-C differed clearly from araC, Dnr & Dox. Genes conferring chemosensitivity to amonafide had a negative correlation for araC, Dnr, and Dox. Genes with a positive correlation for araC, Dnr, and Dox, had a negative correlation with amonafide & azaC. A similar pattern of differences was seen for chemoresistance.

Conclusions: Amonafide is a unique chemical entity whose cytotoxicity is not affected by multi-drug resistance expression. Amonafide may evade many of the pharmacogenomic drivers confering resistance to ara-C and anthracyclines. It should therefore retain greater efficacy in combination with araC and as an alternative to anthracyclines, especially in the treatment of myeloid leukemias.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5384. doi:10.1158/1538-7445.AM2011-5384
Abstract 5396: LPS mimotopes: A novel class of TLR4 agonist
Authors: Shanmugam Arulkumaran , Rajoria Shilpi , George Andrea , Mittelman Abraham , Tiwari Raj K. , Suriano Robert
Published: June 2012

Adjuvant driven inflammation is crucial to mounting an antigen specific immune response and is initiated by the activation of toll like receptor (TLR) proteins. Currently, aluminum based adjuvants remain the only FDA approved adjuvants for vaccines. In an effort to develop a new class of adjuvants, TLR agonists, would be natural candidates. LPS, a major structural component of gram negative bacteria cell walls, has been well studied for its property to induce the systemic inflammation observed in septic shock. The objective of the present study was to identify peptide mimics of LPS that could activate TLR-4 and induce an inflammatory condition congenial to an adaptive immune response and in contrast to LPS not induce septic shock. To this end we used phage display peptide library to identify and isolate LPS peptide mimics. The activity of LPS-TLR-4 interaction was assessed by NF-κB translocation analyses in HEK-BLUE™-4 cells, a cell culture model that expresses only TLR-4. NF-κB nuclear translocation and inflammatory cytokine production was assayed by using the murine macrophage cell line RAW264.7. Increasing the NF-κB nuclear translocation is reflected by IκB-degradation within the cytoplasm. As expected, the concentration of cytoplasmic NF-κB was also decreased, which further attests to the shuttling of NF-κB within the nucleus. Similar results pertaining to increased nuclear localization of NF-κB with simultaneous decrease of cytoplasmic IκB-α and NF-κB were observed with HEK-BLUE™-4 cells. Thus, the results observed in this study suggest that the LPS peptide mimics identified act as adjuvants by virtue of their interaction with TLR-4 and thus serve as novel candidates to be considered as a new class of TLR-4 agonist adjuvants.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5396. doi:10.1158/1538-7445.AM2011-5396
Abstract 5397: Human mesenchymal stem cell-based cell carrier for tumor-homing delivery of replicating retrovirus vectors in glioblastoma models
Authors: Hiraoka Kei , Inagaki Akihito , Logg Christopher R. , Kamijima Shuichi , Hui Kam Man , Marini Frank C. , Kasahara Noriyuki
Published: June 2012

In previous studies, we have demonstrated that replicating murine leukemia virus (RMLV)-based vectors can achieve highly efficient in vivo delivery of prodrug activating genes in glioblastoma models, with infection restricted to actively dividing tumor cells without spread to extratumoral sites, resulting in significantly prolonged survival upon prodrug administration; this approach is now being tested in a multi-center clinical trial.

RMLV vectors can eventually spread to almost all actively dividing GBM cells over time. We are seeking to further improve the efficiency of this novel therapeutic strategy by engineering human mesenchymal stem cells (MSC) to function as RMLV vector producer cells (MSC-VPC). Primary MSC have been shown to actively migrate through tumor masses beyond the immediate injection site and track to diffusely infiltrating tumor foci. In the present study, we developed optimized methods for engineering MSC-VPC, and we then further examined tumor transduction efficiency of MSC-mediated RMLV delivery, and how this delivery method might affect vector replication kinetics in vivo.

First, we evaluated the vector productivity of MSC-VPC in U87 human glioblastoma cells in vitro. Primary human MSCs were infected with RMLV vector AC3-GFP, expressing the GFP marker gene. These MSC were then re-plated at very low density onto a monolayer of naïve U87 glioma cells, and fluorescence was monitored over time. Under the fluorescent microscope, progressive spread of the RMLV vector released from the MSCs could be confirmed, as indicated by increasing GFP(+) U87 cells over time. Next, we tested MSC-VPC in intracranial U87 tumor models in vivo. Five days after intracranial tumor cell implantation, 1E3 transduction units (TU) of AC3-GFP vector or 5E3 MSC-VPC (∼20% pretransduced with AC3-GFP) were stereotactically injected at the tumor site. Tumors were harvested and digested on day 9 for FACS analysis to detect GFP expression. While the highest percentage of GFP(+) cells was 28.6% in the vector supernatant-treated group, up to 45% transduction efficiency was achieved in the MSC-VPC group. These results suggest the use of MSCs as tumor-homing carriers may be provide more efficient delivery of RMLV vectors in human glioma models.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5397. doi:10.1158/1538-7445.AM2011-5397
Abstract 5429: Cytotoxicity of AOH compounds targeting the interaction of caPCNA and its binding partners in human cancer cells
Authors: Shen Fei , Hickey Robert , Kamran Jasmine , Smith Shanna , Phipps Elizabeth , Malkas Linda
Published: June 2012

Previously we reported the identification of an acidic isoform of proliferating cell nuclear antigen (caPCNA) in various cancer cells. Proliferating Cell Nuclear Antigen (PCNA) interacts with multiple binding partners to carry out vital cellular processes including DNA replication, DNA damage repair, and cell-cycle progression. We hypothesize that caPCNA performs similar functions specifically in cancer cells and, therefore, disrupting interactions of caPCNA with its binding partners will prevent necessary cellular functions, resulting in cytotoxicity to cancer cells. AOH compounds were generated based on a focused computer molecular “docking” search for small molecules that specifically targeted the interaction of caPCNA and its binding partner FEN1. MTT assays suggest that several AOH compounds have promising anti-proliferation effects in human breast and pancreatic cancer cells with EC50 values as low as or less than 10uM (lead compounds). To further evaluate the cytotoxicity of lead AOH compounds, clonogenic survival assays were performed in MCF-7 cells treated with the small molecules for 2 hours. Results showed that AOH compounds induced cytotoxicity in cancer cells in a dose-dependent manner. The IC50s of these compounds were between 10 to 20uM in MCF-7cells. To investigate the effects of the AOH compounds on DNA replication and the cell cycle, in vitro SV40 DNA replication assays and flow cytometric analysis were performed. The G2/M phase cell population was increased from 8% to 30-80% in MCF-7 cells treated with 25uM AOH compounds for 48 hours, indicating an induction of G2 arrest. AOH compound at 10uM inhibited in vitro DNA replication in malignant cell extracts by 70-80% relative to untreated correspondent cell extracts. Taken together, the potent cytotoxicity of AOH compounds in cancer cells is correlated with their inhibition of DNA replication and induction of cell cycle arrest. The compounds may be useful in the future for clinical cancer chemotherapy as a single anticancer agent and/or in combination with other anti-neoplastic agents.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5429. doi:10.1158/1538-7445.AM2011-5429
Abstract 5432: Spirooxindole derivative (SOID-8) inhibits proliferation and induces apoptosis by blocking JAK2/STAT3 signaling in melanoma cells
Authors: Tian Yan , Nam Sangkil , Liu Lucy , Yakushijin Fumiko , Buettner Ralf , Liang Wei , Yang Fan , Horne David , Jove Richard
Published: June 2012

Melanoma is the most malignant skin cancer, and is generally refractory to current chemotherapy, so new treatment strategies are needed. In this study, we show that a spirooxindole derivative, SOID-8, which is a synthetic analogue inspired by the natural product, spirotryprostatin B, significantly inhibits cell proliferation in four established human melanoma cell lines. This decrease in viability of A2058 and A375 melanoma cells is associated with apoptosis, as confirmed by an increase in poly(ADP-ribose)polymerase cleavage. In addition, the antiapoptotic protein Mcl-1, a member of the Bcl-2 family, is downregulated and correlated with SOID-8 induced apoptosis. Morevoer, SOID-8 inhibits tyrosine phosphorylation of Signal Transducer and Activator of Transcription 3 (STAT3) in both melanoma cell lines in a dose- and time-dependent manner. In contrast, phosphorylation of AKT (protein kinase B) is reduced by SOID-8 only at high concentrations, and phosphorylation of MAPK (extracellular signal-regulated kinase 1/2) is not inhibited at all by SOID-8 in these cells. Furthermore, this compound decreases the phosphorylated Janus kinase-2 (JAK2) levels in a dose- and time-dependent fashion. Importantly, SOID-8 inhibits phosphorylation of STAT3 and JAK2 induced by IL-6 stimulation in A2058 and A375 cells. In summary, our results show that SOID-8 selectively blocks JAK2/STAT3 signaling as well as expression of apoptosis regulatory proteins, associated with inhibition of cell proliferation and induction of apoptosis in melanoma cells. These data suggest that antitumor activity of the spirooxindole derivative SOID-8 is at least partially due to inhibition of JAK2/STAT3 signaling in melanoma cells and is a promising small molecule candidate for melanoma therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5432. doi:10.1158/1538-7445.AM2011-5432
Abstract 5439: A novel drug sensitivity assay method for 3D cultured cell using an imaging device
Authors: Sakamoto Ruriko , Sakemura Noriko , Shimomura Manami , Hirakawa Noboru , Watanabe Hirotada , Tanaka Satoru , Yoshida Kaori , Nakatsura Tetsuya
Published: June 2012

Three-dimensional (3D) cultured cells are useful for the physiological study of tumor cells owing to their similar characteristics. Currently, the popular methods for 3D cell culture-for example, collagen gel or the matrix method-involve complicated procedures that often result in experimental errors. We attemted to develop a novel technique for the use of 3D cell culture in a novel drug sensitivity assay using an imaging technique. We used a NanoCulture® plate (NCP) for 3D cell culture of the human breast cancer cell lines BT474 and T47D for forming multicellular spheroids and used these in a drug sensitivity assay for trastuzumab and paclitaxel by employing the imaging device BioStation CT. The NCP has a fine pattern carved on the surface of the wells’ bottoms, which provides scaffolding for cells with expanding pseudopodia. Thus, the cells can move and aggregate to form uniform spheroids on the NCP. These spheroids further migrate and fuse each other during culture. The effects of anticancer drugs-i.e., a decrease in the migration velocity of spheroids and suppression of spheroid fusion in a dose-dependent manner-were estimated using NCP-cultures spheroids analyzed using sequential BioStation CT images. These results were compared to the conventional assay method of ATP quantification with a good agreement. We confirmed the antitumor effect of the drugs on cells seeded in a single well of the 96-well plate by this technique. We expect this method to be useful in research on new antitumor agents and in drug sensitivity tests for individually tailored cancer treatments.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5439. doi:10.1158/1538-7445.AM2011-5439
Abstract 5448: Pharmacogenetics of drug transporters may be useful to identify chronic myeloid leukemia patients who are less likely to achieve molecular responses to imatinib: Implications for treatment optimization in the era of new tyrosine kinase inhibitors
Authors: Soverini Simona , Angelini Sabrina , Barnett Matt , Ravegnini Gloria , Pane Fabrizio , Hughes Timothy P. , White Deborah , Kim Dong-Wook , Saglio Giuseppe , Rosti Gianantonio , Woodman Richard , Woodman Richard , Hrelia Patrizia , Biasco Guido , Baccarani Michele , Martinelli Giovanni
Published: June 2012

The availability of multiple options for chronic myeloid leukemia (CML) treatment is not paralleled by the availability of biological predictors of outcome allowing to identify patients (pts) who are more likely to benefit from dasatinib or nilotinib rather than imatinib (IM). We thus investigated a panel of 20 SNPs in ABCB1, ABCG2, SLC22A1, OCTN1, CYP3A4 and CYP3A5 genes that can be hypothesized to influence IM transport and metabolism in 189 newly diagnosed CML pts enrolled in the TOPS phase III trial (Cortes et al, J Clin Oncol 2010). Median age was 46 yrs; male to female ratio was 103:86; 156 (83%) pts were Caucasian and 23 (12%) were Asian; low, intermediate and high Sokal risk pts were 84 (44.4%), 65 (34.4%) and 40 (21.2%), respectively. Baseline demographic/clinical features did not differ significantly from those of the entire population enrolled. Treatment outcomes (major molecular response [MMR]; complete molecular response [CMR]) were compared according to i) each candidate genotype ii) summary measures based on combinations of SNPs in the same gene and iii) summary measures based on combinations of SNPs in functionally related genes (uptake; efflux). Additive models, with SNPs represented as number of major alleles, were used. Significant results are summarized in the Table below and will be presented in detail. Cumulative incidence plots were also analysed, with similar results. Our data suggest that in CML pts, genotyping should be taken into account in an attempt to further individualize treatment, with the aim of enhancing efficacy in terms of MMR and CMR achievement. On the basis of our findings, stratification of pts according to genotypes may be proposed for selection between IM and second generation TKIs, and represents an attractive opportunity for new clinical trials.

Supported by Novartis, TOPS Correlative Studies Network

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5448. doi:10.1158/1538-7445.AM2011-5448
Abstract 5452: Functional genome-wide approach identifies genes associated with chemotherapeutic susceptibility in individuals of African descent
Authors: Wheeler Heather E. , Stark Amy L. , Gorsic Lidija K. , Gamazon Eric R. , Cox Nancy J. , Dolan M. Eileen
Published: June 2012

Chemotherapeutic agents are used in the treatment of many cancers, yet variable resistance and toxicities among individuals limit successful outcomes. Several studies have indicated outcome differences associated with ancestry among patients with various cancer types. We performed genome-wide association studies (GWAS) in lymphoblastoid cell lines derived from Yoruba (YRI; n = 176) and African American (ASW; n = 83) populations and identified SNP predictors of cellular susceptibility to cisplatin, carboplatin, capecitabine and ara-C. To account for population structure in African American population, we incorporated local ancestry information into our association model. We found that chemotherapeutic susceptibility SNPs in the YRI are enriched for expression quantitative trait loci (eQTLs, p<10-3). Most of these are trans eQTLs and thus simply examining the region directly surrounding a SNP that associates with a phenotype of interest for possible functional genes is inadequate. Traditional GWAS that test single markers are powered to detect SNP associations with relatively strong effects, but are unable to detect multiple smaller effects working together. Using a novel functional gene-based genome-wide association approach, we identified 10, 13, and 1 suggestive candidate genes for association with cytarabine-, carboplatin-, and cisplatin-induced cytotoxicity, respectively (p≤10-4) in ASW. Functional GWAS in the YRI resulted in the genome-wide significant association of 234 genes with cisplatin IC50, 81 genes with 5’-deoxyfluorouridine AUC, 64 genes with carboplatin IC50 and 13 genes with cytarabine AUC (p<10-6). Our genome-wide SNP- and gene-based approaches that incorporate local ancestry information can be used to elucidate genes functionally contributing to a wide range of phenotypes in African American populations.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5452. doi:10.1158/1538-7445.AM2011-5452
Abstract 5456: Functional genomics reveals diverse cellular processes that modulate tumor cell response to oxaliplatin
Authors: Harradine Kelly , Kassner Michelle , Chow Donald , Aziz Meraj , Von Hoff Daniel D. , Baker Joffre , Yin Hongwei , Pelham Robert J.
Published: June 2012

Oxaliplatin is widely used to treat colorectal cancer, as both adjuvant therapy for resected disease and palliative treatment of metastatic disease. However, a significant number of patients experience serious side effects from oxaliplatin treatment, including prolonged neurotoxicity, creating an urgent need for biomarkers of oxaliplatin response or resistance to direct therapy to those most likely to benefit. As a first step to improve selection of patients for oxaliplatin-based chemotherapy, we have conducted an in vitro cell-based small interfering RNA (siRNA) screen of 500 genes aimed at identifying genes whose loss of expression alters tumor cell response to oxaliplatin. The siRNA screen identified twenty-seven genes, that when silenced, significantly altered colon tumor cell line sensitivity to oxaliplatin. Silencing of a group of putative resistance genes increased the extent of oxaliplatin-mediated DNA damage and inhibited cell cycle progression in oxaliplatin-treated cells. The activity of several signaling nodes, including AKT1 and MEK1, was also altered. We used cDNA transfection to over-express two genes (LTBR and TMEM30A) that were identified in the siRNA screen as mediators of oxaliplatin sensitivity. In both instances, over-expression conferred resistance to oxaliplatin. In summary, this study identifies numerous putative predictive biomarkers of response to oxaliplatin which should be studied further in patient specimens for potential clinical application. Diverse gene networks appear to influence tumor survival in response to DNA damage by oxaliplatin. Finally, those genes whose loss of expression (or function) is related to oxaliplatin sensitivity may be promising therapeutic targets to increase patient response to oxaliplatin.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5456. doi:10.1158/1538-7445.AM2011-5456
Abstract 5465: Modulation of DMS612 (BEN) pharmacokinetics and metabolism in mice by disulfiram, and aldehyde dehydrogenase inhibitor
Authors: Parise Robert A. , Beumer Jan , Clausen Dana , Egorin Merrill , Covey Joseph , Eiseman Julie
Published: June 2012

Introduction: DMS612 (NSC 281612, BEN) is an alkylating agent in clinical trials based on its in vitro and in vivo activity against renal cell carcinoma. We previously reported that BEN is rapidly metabolized into its carboxylic acid (BA), and that BEN and BA undergo chemical degradation both in vitro and in vivo. In addition, we demonstrated that BEN is rapidly metabolized into at least 13 different analytes in vivo. We hypothesized that BEN is metabolized to BA by aldehyde dehydrogenase (ALDH). In an attempt to increase the exposure to BEN, we explored the effect of the ALDH inhibitor disulfiram on the pharmacokinetics of BEN in mice.

Materials & Methods: Female CD2F1 mice were dosed with either 20 mg/kg BEN i.v. alone or 24 h after the i.p. administration of 300 mg/kg disulfiram. Plasma and urine concentrations of BEN and its metabolites were quantitated by LC-MS/MS. Plasma pharmacokinetic parameters were calculated non-compartmentally. Urinary excretion of BEN and metabolites was calculated as percentage of the dose.

Results: BEN was metabolized to at least 13 different products as previously reported. In the BEN alone study, BEN was metabolized quickly with a half-life <5 min. The half-lives of the metabolites were < 2 h. Pretreatment with disulfiram resulted in a 300-fold increase in exposure to BEN, from AUC0-inf 143 ng/mL*min to 40,515 ng/mL*min, while BA exposure remained similar, at AUC0-inf 254,280 ng/mL*min after BEN alone to AUC0-inf 274,947 ng/mL*min after disulfiram. In addition, the half-lives and AUCs of some of the metabolites in the BEN + disulfiram study appeared to be longer than when BEN was administered alone. Urinary excretion of BEN was increased 50% after disulfiram (from 1% to 1.5 % of the dose), BA excretion accounted for 5.8% of the dose after BEN alone and this was not markedly affected by disulfiram pretreatment.

Conclusions: BEN is rapidly metabolized into many metabolites, which could affect the efficacy of BEN as an anti-neoplastic agent. We have demonstrated that by administering the ALDH inhibitor disulfiram the exposure to BEN is greatly increased, suggesting that ALDH is at least partly responsible for the rapid metabolism of BEN. However, the plasma exposure to BA increased only 8%. Our results will aid in the interpretation of ongoing clinical studies with BEN, which include genotyping for ALDH.

Support: N01-CM07106, N01-CM52202, P30-CA47904.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5465. doi:10.1158/1538-7445.AM2011-5465
Abstract 5469: Pharmacokinetics and activity of nanoliposomal irinotecan (MM-398) against Ewings Sarcoma xenografts are superior to the conventional irinotecan formulation
Authors: Wang Jing , Zhuo Rupeng , Drummond Daryl , Reynolds C. Patrick , Kang Min H.
Published: June 2012

Background: Irinotecan (CPT-11) is an antineoplastic prodrug, of which SN-38 is an active metabolite. Liposomal CPT-11 was developed to improve systemic and tumor exposure to CPT-11 and its active metabolite by reducing the exposure of CPT-11 to neutral and basic pH, in which CPT-11 is hydrolyzed into an inactive carboxylate form. The aims of the current study are 1) to compare the plasma and tissue/tumor pharmacokinetics of nanoliposomal CPT-11 (in clinical trials as PEP02 or MM-398) and conventional irinotecan in mice, and 2) to compare anti-tumor activity of the two formulations against Ewings Sarcoma murine xenografts. Methods: An assay using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed to measure CPT-11 and SN-38 concentrations in plasma and tissue. Plasma and tissue pharmacokinetics of liposomal and conventional irinotecan were characterized in Balb/c mice (non-tumor bearing); pharmacokinetics and activity were assessed in athymic nu/nu mice xenografted with human Ewings sarcoma. Results: Following a 20 mg/kg dose of intravenous liposomal irinotecan, both plasma and tumor concentrations of CPT-11 and SN-38 were approximately 10-fold higher than conventional irinotecan. The Cmax and AUC were dose-proportionally increased after a single dose of liposomal irinotecan in non-tumor bearing mice. In mice xenografted with Ewings sarcoma (CHLA-258), liposomal irinotecan significantly extended event-free survival of mice compared with controls or conventional irinotecan (P<0.05). Conclusions: Our data demonstrate that 1) liposomal CPT-11 achieves higher plasma and tissue concentrations with longer duration compared with conventional irinotecan, and that 2) liposomal formulation has greater anti-tumor activity relative to conventional irinotecan. These results suggest that liposomal irinotecan may provide improved anti-tumor activity over conventional irinotecan by increasing systemic and tumor exposures to the SN-38 active metabolite.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5469. doi:10.1158/1538-7445.AM2011-5469
Abstract 5492: Preclinical study of the PARP inhibitor ABT-888 in metastatic prostate cancer
Authors: Zhang Jingsong , Mcgregor Natalie , Hussain Maha H. , Chinnaiyan Arul
Published: June 2012

Background: Despite recent advances in androgen deprivation therapy, chemotherapy and immunotherapy, metastatic prostate cancers (mPCa) eventually become resistant to these treatments through further mutations. Cancer cells often diminish their DNA repair pathways to obtain high mutation rates. We aimed to develop a therapeutic approach that directly targets cells with high mutation rates and explored the therapeutic potential of PARP inhibitor, ABT-888 (kindly provided by Abbott) in mPCa preclinical models. Methods and Results: Meta-analysis of 5 published prostate cancer gene expression profiles with total of 53 metastatic samples and 183 primary samples were performed with oncomine 4.1. BRCA1 was among genes significantly over expressed in mPCa. Inhibiting BRCA1 expression with shRNA in Lncap (intact PTEN) and PC3 (loss of PTEN) cells, however, did not lead to synthetic lethality when ABT-888 (up to 10uM) were added in the in vitro cytotoxicity assays. When ABT-888 was combined with DNA damaging chemotherapy agents, synergies in cell killing were observed with 100nM of ABT-888 and 10nM SN38, an active metabolite of topoisomerase I inhibitor CPT-11. Such synergies were observed at higher dose levels with Temazolomide (1uM) and ABT-888 (1uM). The enhanced cell killing correlated well with inhibition of PAR and increased formation of DNA double strand breaks. No synergies with ABT888 were observed with topoisomerase II inhibitor (etoposide and mitoxantrone) or platinums in the WST-1 cytotoxicity assays. The CPT-11 and ABT888 combination was then tested in PC3 mouse xenografts with 4 treatment groups: vehicle control, ABT-888, CPT-11, and ABT-888 plus CPT-11. ABT-888 was given by oral gavages at 12.5mg/kg on days 1-5 of each 21 day cycle; whereas CPT-11 was given by intraperitoneal injection at 60mg/kg on days 1 and 5 of each 21 day cycle. Compared to vehicle control, ABT-888 by itself had no anti-tumor activities. The inhibition of tumor growth by CPT-11 was further enhanced when it was combined with ABT-888. More than 30% tumor volume shrinkage was observed in 4 of the 8 xenografts after 2 cycles of treatments with ABT-888 and CPT-11. These anti-tumor effects, however, were not sustainable beyond treatment cycles. Conclusion: ABT-888 enhanced the anti-tumor activities of CPT-11. The dose and schedule of this combination will be modified and its anti-tumor activities will be compared with docetaxel in future pre-clinical studies.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5492. doi:10.1158/1538-7445.AM2011-5492
Abstract 5496: Cetuximab induces synthetic lethality with the poly (ADP-Ribose) polymerase (PARP) inhibitor ABT-888 in head and neck cancer
Authors: Whitley Alexander C. , Nowsheen Somaira , Trummell Hoa , LoBuglio Albert , Bonner James A. , Yang Eddy S.
Published: June 2012

Purpose: Overexpression/amplification of the epidermal growth factor receptor (EGFR) is a hallmark of head and neck cancers and confers increased resistance and inferior survival rates. Despite targeted agents against EGFR, such as cetuximab, almost half of treated patients fail this therapy. PARP inhibitors (PARPi) have gained recent attention due to their unique selectivity in killing homologous recombination (HR)-deficient tumors while maintaining minimal toxicity in normal tissues. As EGFR inhibition has been reported to alter cellular DNA repair capacity, we investigated whether cetuximab could induce a transient DNA repair deficit and subsequently induce a synthetic lethality with the PARPi ABT-888 in head and neck cancer cells.

Methods: The head and neck cancer cell lines UM-SCC1, UM-SCC6, and FaDu were used in this study. Kinetics of DNA damage and repair were assessed by immunofluorescence staining of cells for γ-H2AX, Rad51, and DNA-Pk foci at various time points following irradiation (IR). Cell viability was determined via the ATPlite as well as colony formation assays. Apoptosis was evaluated by Annexin V staining as well as cleaved caspase 3 and 9 levels. Cell cycle analysis was performed via flow cytometry.

Results: Cetuximab increases γ-H2AX foci, which are well established markers of DNA double strand breaks (DSBs), in head and neck tumor cells. This coincides with reduced DSB-repair as indicated by attenuation of IR-induced Rad51 and DNA-Pk foci, which are well characterized in situ markers of the homologous recombination (HR) and non-homologous end-joining (NHEJ) DNA repair pathways, respectively. Importantly, cetuximab induces synthetic lethality with the PARPi ABT-888 through a mechanism involving persistent DNA damage and subsequent activation of the intrinsic pathway of apoptosis. The observed effects are not due to cell cycle redistribution.

Conclusions: By generating a DSB repair deficiency, cetuximab can render head and neck tumor cells susceptible to PARP inhibition. The combination of cetuximab and the PARPi ABT-888 can thus be an innovative treatment strategy to enhance therapeutic ratio and improve outcomes in head and neck cancer patients. Furthermore, this strategy may also be feasible for other EGFR overexpressing tumors, including lung and brain cancers.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5496. doi:10.1158/1538-7445.AM2011-5496
Abstract 5517: Distinct myeloid suppressor cell subsets correlate with plasma IL-6 and IL-10 and reduced interferon-α signal transduction in CD4+ T cells from patients with gastrointestinal malignancy
Authors: Mundy Bethany L. , Young Gregory S. , Bauer Todd , Binkley Elaine , Bloomston Mark , Bill Matthew A. , Bekaii-Saab Tanios , Carson William E. , Lesinski Gregory B.
Published: June 2012

Interferon-alpha (IFNα) can promote anti-tumor immunity through its actions on immune cells. We have shown in murine models that a class of immune suppressor cells known as myeloid-derived suppressor cells (MDSC) have inhibitory effects on IFN signal transduction and gene regulation. Interleukin (IL)-6 and IL-10 are produced by tumor cells in cancer patients and can regulate the survival and function of MDSC. This study evaluated relationships between plasma IL-6, IL-10, circulating MDSC subsets and IFNα-induced signal transduction in 40 patients with gastrointestinal (GI) malignancies. Plasma IL-6 and IL-10 levels were significantly higher in patients versus normal donors. CD33+HLADR−CD11b+CD15+ and CD33+HLADR−/lowCD14+ MDSC were also elevated in patients versus normal donors (p<0.0001). Prior studies suggest that CD15 divides human MDSC into granulocytic (CD15+) and monocytic (CD15−) subsets. Therefore relationships between CD15 expression on MDSC and cytokines elevated in GI patients were examined. A significant correlation between plasma IL-6 with CD33+HLADRCD15+ MDSC (p=0.008) and IL10 with CD33+HLADR−CD15− MDSC (p=0.002) was observed. The level of CD15+ and CD15− but not CD14+ MDSC subsets were inversely correlated with IFNα-induced STAT1 phosphorylation in CD4+ T cells, while co-culture with in vitro generated MDSC led to reduced IFNα-responsiveness in PBMC from normal donors. In a multivariable Cox proportional hazards model, an increased percentage of the CD33+HLADR−CD15− MDSC subset was associated with reduced overall survival (hazard ratio = 1.43; p = 0.049) while an increased percentage of the CD33+HLADR−/lowCD14+ subset was associated with greater overall survival (hazard ratio = 0.69, p=0.033). These data provide evidence for a unique relationship between specific cytokines, MDSC subsets and IFNα responsiveness in patients with GI malignancies.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5517. doi:10.1158/1538-7445.AM2011-5517
Abstract 5519: Vaccination of melanoma patients with CD40L/IFN-γ activated dendritic cells reveals a correlation between IL-12p70 production and CD8+ T cell priming to the melanoma differentiation antigen gp100
Authors: Carreno Beatriz M. , Becker-Hapak Michelle , Chan Megan , Lie Wen-Rong , Linette Gerald P.
Published: June 2012

Ex-vivo generated dendritic cells (DC) have been used as therapeutic vaccines for the treatment of patients with metastatic cancer. However, these first-generation vaccines consist of DC activated to up-regulate costimulatory molecules with minimal to absent IL-12p70 production. Inflammatory cytokines, primarily IL-12p70 and interferons, provide a critical third signal along with antigen (signal 1) and costimulation (signal 2) for optimal effector CD8 T cell expansion/differentiation and memory formation. In order to generate IL-12p70-producing DC, a GMP-grade cell line expressing CD40L was developed and used in conjunction with IFN-γ to activate monocyte-derived DC. Stage IV melanoma patients (n=6) received an initial priming dose of CD40L/IFN-γ activated DC pulsed with 3 gp100 melanoma peptides (G154, G209-2M, G280-9V), followed by additional DC doses every 3 weeks for a total of 6 immunizations. Peripheral blood mononuclear cells isolated weekly during the course of immunizations were used to evaluate the kinetics and magnitude of vaccine-induced gp100-T cell responses. In all but one patient CD8+ T cell responses to all 3 gp100 peptides were detected, with strongest proliferative responses observed after 2 DC immunizations. Magnitude of responses was not heightened with further immunizations. Antigen-specific frequencies to the high affinity G154 peptide were consistently lower than those to low affinity G209 and G280 peptides. Notably, we observe a correlation between DC IL-12p70 production, immune responses to gp100, and clinical efficacy of vaccination. Patients (n=3) with highest DC IL-12p70 production levels exhibit high gp100 antigen-specific frequencies and are in remission (n=1) or have stable disease (n=2). A qualitative analysis of T cell responses generated among patients is currently underway. These results underscore the important role of DC activation status in vaccination and provide an immunological rationale for vaccine design whereby IL-12p70 contributes to effective immune-based therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5519. doi:10.1158/1538-7445.AM2011-5519
Abstract 5538: Sarcomas in TP53 germline mutation carriers
Authors: Ognjanovic Simona , Olivier Magali , Bergemann Tracy L. , Hainaut Pierre
Published: June 2012

Sarcoma plays a central role in Li-Fraumeni syndrome (LFS) definition. Germline mutations in TP53 gene underlie this rare familial syndrome and are detected in over 80% of LFS patients.

The International Agency for Research on Cancer (IARC) maintains a database of germline TP53 mutations that collects published data on LFS and related syndromes and provides baseline information about TP53 mutation prevalence and phenotype in these patients.

We analyzed the characteristics of germline TP53 germline mutations in LFS and related syndrome patients with sarcoma using the IARC TP53 Database. The prevalence of individual sarcoma types and their age/gender distribution in TP53 mutation carriers were compared to sporadic sarcomas in Caucasians obtained by SEER registry analysis using the SEERStat program.

Sarcoma represented 25% of all tumors diagnosed in TP53 carriers in this study. We confirmed young age of sarcoma onset among carriers, with 95.6% of cases diagnosed before the age of fifty years, as opposed to 38.3% of sporadic cancer. Carriers had increased risk for osteosarcoma in both children/adolescents and adults (OR=1.41, 95% CI=1.02-1.94, and OR=4.61, 95% CI=2.72-7.83), while increased risk for rhabdomyosarcoma was confined to carriers younger than 5 years (OR=11.6, 95%CI=6.1-21.9, p<0.00001). Analysis of the association of mutations with specific sarcoma types revealed that mutations in the oligomerization domain (codon 344 and 337) increased the risk of leiomyosarcoma (OR=10.1, 95% CI=3.4-29.9). Analysis of codons most frequently mutated in sarcoma showed that four codons (220, 275, 282, 344) were associated with 3-fold increased risk of sarcoma, compared to other cancers in TP53 carriers.

In conclusion, this study provided further evidence for genotype-phenotype correlations in germline TP53 mutations carriers.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5538. doi:10.1158/1538-7445.AM2011-5538