tbuckley/cabot-search huggingface dataset:
Abstract 1522: Targeted gene therapy · c-MYC and hTERT in the scope
Authors: Francine Rezzoug, Shelia D. Thomas, Segen Tella, Donald M. Miller
Journal: Cancer Research (2017)

Abstract In the past decade immunotherapy and kinase inhibitors have revolutionized the approach for cancer therapy, particularly for melanoma which has benefit from this new therapy in the last 5 years. Although, new treatment increase patient survival, there is no cure and treatments are often limited to a subtype of patients. Therefore there is still an urgent need for efficient therapy for melanoma. Among potential targets for cancer therapy, c-MYC and hTERT which are overexpressed in up-to 85% of all cancers are the most promising. The overexpression of hTERT provides indefinite division to cancer cells. Deregulation of c-MYC affect a large array of genes involved in cell cycle, proliferation/differentiation and apoptosis. Notably, both c-MYC and hTERT genes have in their promoter area a G-rich sequence that form secondary structure called G-quadruplex. These G-quadruplex structures are part of the silencers and are required for the repression of c-MYC or hTERT transcription. Mutations in the G-rich sequences of hTERT promoter destabilize the G-quadruplex and are associated with incidence of melanoma. We have shown that oligonucleotides encoding for the G-quadruples sequences of these genes promoter downregulate their respective gene expression and inhibit cell growth in different cell lines. We investigated the effect of targeting c-MYC or hTERT gene expression in melanoma cell lines using oligonucleotides targeted to the silencer G-quadruplex sequence. Four cell lines where investigated (SK-Mel-2, SK-Mel-3, SK-Mel-28 and A375) for the effect of Pu27 (targeting c-MYC) and Tert-FL (targeting hTERT) on cell proliferation using MTT assay. The treatment for 6 days resulted in 60% growth inhibition in the presence of Pu27 and 50% in the presence of Tert-FL for SK-Mel-2, SK-Mel-3, SK-Mel-28 while A375 was less sensitive. Gene expression evaluated by QRT-PCR showed down-regulation of c-MYC and hTERT in cell exposed to Pu27 and hTERT in cells exposed to Tert-FL. hTERT expression is regulated by c-MYC and in our experiment the down-regulation of c-MYC correlate with down-regulation of hTERT suggesting a cascade effect. In addition, SOX2 gene expression was also down-regulated by Pu27 suggesting an effect on the cancer stem cells (CSC). Our data demonstrate that oligonucleotides targeted to c-MYC and hTERT down-regulate gene expression associated with melanoma cell growth inhibition and possibly on metastasis. Citation Format: Francine Rezzoug, Shelia D. Thomas, Segen Tella, Donald M. Miller. Targeted gene therapy · c-MYC and hTERT in the scope [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1522. doi:10.1158/1538-7445.AM2017-1522
Evaluation of complete response rate at 30 months (CR30) as a surrogate for progression-free survival (PFS) in first-line follicular lymphoma (FL) studies: Results from the prospectively specified Follicular Lymphoma Analysis of Surrogacy Hypothesis (FLASH) analysis with individual patient data (IPD) of 3,837 patients (pts).
Authors: Daniel J. Sargent, Qian Shi, Sabine De Bedout, Christopher Flowers, Nathan Hale Fowler, Tommy Fu, Anton Hagenbeek, Michael Herold, Eva Hoster, Jane Huang, Eva Kimby, Marco Ladetto, Franck Morschhauser, Tina Nielsen, Kenichi Takeshita, Nancy Valente, Umberto Vitolo, Emanuele Zucca, Gilles A. Salles
Journal: Journal of Clinical Oncology (2015)

8504 Background: Although PFS is the standard endpoint for new drug approvals in first-line FL, advances in efficacy (median PFS >7 y) coupled with the indolent nature of FL necessitate extended patient follow-up in clinical trials. The FLASH group conducted a meta-analysis to evaluate whether treatment effects on CR30, an earlier endpoint, could accurately predict treatment effects on PFS. Methods: Correlation of CR30 odds ratio (OR) with PFS hazard ratio (HR) was evaluated using both linear regression (R2WLS) and copula bivariate (R2Copula) models. Prespecified criteria for CR30 surrogacy required either R2WLS or R2Copula ≥ 0.80 with a lower bound of the 95% confidence interval (CI) > 0.60, with neither estimate < 0.70. The minimum CR30 difference to predict significant PFS difference was calculated. Results: Data from 13 randomized first-line trials (8 induction, 5 maintenance trials) with IPD for 3837 pts were included. The prespecified threshold for surrogacy was met: R2WLS of 0.88 (95% CI, 0.77-0.96) and R2Copula of 0.86 (95% CI, 0.72-1.00, Table), supporting the hypothesis that treatment effects on CR30 predict effects on PFS in pts with previously untreated FL. Multiple sensitivity and IPD surrogacy analyses supported the robustness of the primary analysis. A minimum 10% absolute improvement in CR30 over a control CR30 of 50% predicted significant improvement in PFS. Conclusions: This large IPD meta-analysis of chemo/immunotherapy trials establishes CR30 as a surrogate endpoint for PFS in first-line FL trials and supports its use to expedite therapeutic development. Trial type Trials, N (pts) R2WLS (95% CI)a R2Copula (95% CI)a Overall 13 (3837) 0.88 (0.77-0.96) 0.86 (0.72-1.00) Rituximab included 9 (2851) 0.85 (0.62-0.97) 0.80 (0.56-1.00) No rituximab 4 (986) 0.91 (0.05-1.00) 0.96 (0.90-1.00) Induction 8 (2207) 0.89 (0.75-0.98) 0.89 (0.74-1.00) Maintenance 5 (1630) 0.93 (0.84-1.00) 0.89 (0.71-1.00) a R2 values range from 0 (no association) to 1 (perfect prediction).
Abstract 2364: Src-like adaptor protein 2 negatively regulates FLT3 and KIT downstream signaling
Authors: Sausan A. Moharram, Lars Rönnstrand, Julhash U. Kazi
Journal: Cancer Research (2017)

Abstract Type III receptor tyrosine kinases (RTKs) including FLT3 and KIT play a major role in cell differentiation, proliferation, and survival of hematopoietic stem cells. FLT3-ITD and KIT-D816V mutations are the most common oncogenic mutations in FLT3 and KIT found in hematological cancers. These mutations lead to constitutive activation of proliferative and survival signals. Tyrosine kinase inhibitors (TKIs) in combination with chemotherapy display promising results in a clinical setting, but patients develop resistant disease after short-term treatment,. Hence, proteins that regulate the activity of RTKs can be alternative targets for patients carrying these mutations. Activation of FLT3 and KIT results in phosphorylation on several tyrosine residues that recruit SH2 domain-containing signaling proteins. In this study we identified Src-like adaptor protein 2 (SLAP2) as a potent FLT3 and KIT interacting protein. The interaction requires an intact SH2 domain of SLAP2 as well as phosphorylation of the receptor. Overexpression of SLAP2 in murine proB Ba/F3 cells inhibited oncogenic FLT3-ITD-mediated cell proliferation and colony formation. SLAP2 displayed a similar inhibitory potential in cells expressing KIT-D816V. SLAP2 partially blocked phosphorylation of several FLT3 and KIT downstream signaling proteins such as AKT, ERK and p38. Moreover, SLAP2 expression inhibited FLT3-ITD-mediated STAT5 phosphorylation and KIT-D816V-mediated STAT3 phosphorylation. SLAP2 expression significantly accelerated ubiquitination-mediated degradation of FLT3 and KIT. Collectively, these data suggest that SLAP2 negatively regulates FLT3 and KIT signaling and therefore, modulation of SLAP2 expression levels may become a potential target for anticancer therapy. Citation Format: Sausan A. Moharram, Lars Rönnstrand, Julhash U. Kazi. Src-like adaptor protein 2 negatively regulates FLT3 and KIT downstream signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2364. doi:10.1158/1538-7445.AM2017-2364
Abstract 4405: A new energy restriction mimetic decreases survival and FOXM1 expression in pancreatic cancer cells
Authors: Laura Scolaro, Susan Lanza-Jacoby
Journal: Cancer Research (2017)

Abstract Pancreatic cancer is a deadly disease with only 6% of the patients living longer than 5 years. Even if the disease is diagnosed when it is localized, the 5-year survival rate is approximately 19%. A characteristic of cancer cell metabolism is a shift from oxidative phosphorylation to aerobic glycolysis known as the Warburg effect. It is well known that calorie restriction (CR) is a powerful intervention that suppresses tumorigenesis in animal models by targeting glycolysis and oncogenic signaling pathways. Recent studies have shown that the metabolic responses characteristic of CR can be obtained with the use of energy restriction mimetics (ERM). The purpose of this study is to evaluate a new ERM, OSU-CG5 in altering growth of pancreatic cancer cells and nutrient-sensitive signaling pathways. Tumors including those of the pancreas have uncontrolled proliferation necessitating increased fuel demands by increasing glucose availability and altering metabolic signaling pathways. Since ERM have been reported to target glucose transport, we evaluated whether OSU-CG5 alters glucose transport (Glut) proteins and glucose uptake. Glut1, but not Glut2, 3, 4, and 6, were overexpressed in Panc-1 cells with a 6-fold higher expression compared to HPNE cells. Glut proteins were not altered in MiaPaca cells. OSU-CG5 did not alter Glut1 protein expression in either cell line. Silencing Glut1 also had no effect on the cytoxicity of OSU-CG5. OSU-CG5 did not alter glucose uptake when measured in different concentrations of glucose in the media. Cell survival, as measured with Pico green, was decreased after OSU-CG5 treatment with an IC 50 of 3uM when cultured in physiological concentration of 5 and 10mM of glucose. FOXM1 is unregulated in pancreatic cancer and a promoter of the Warburg effect. We found that OSU-CG5 significantly decreased expression of FOXM1 in Panc1 and MiaPaca cells. Our findings indicate that OSU-CG5 does not inhibit the growth of Panc1 and MiaPaca pancreatic cancer cells by decreasing glucose uptake but may target the FOXM1 signaling pathways. Citation Format: Laura Scolaro, Susan Lanza-Jacoby. A new energy restriction mimetic decreases survival and FOXM1 expression in pancreatic cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4405. doi:10.1158/1538-7445.AM2017-4405
Abstract 484: Epigenetic regulation of hsa-miR-3663 in colon cancer
Authors: Laia Pique, Humberto Jorge Ferrerira, Manel Esteller
Journal: Cancer Research (2017)

Abstract Colon Cancer is the third most common cancer in the world and a major cause of morbidity and mortality. Molecular mechanisms of colon carcinoma have been deeply studied and current evidences indicate that microRNAs play a pivotal role in its tumorigenesis and progression. MicroRNAs (miRNAs) are small 19 to 22 nucleotides of RNA classified as non-coding RNAs that negatively regulate gene expression at the post-translational level controlling numerous biological processes including development, cell proliferation, apoptosis, differentiation and cell migration. Aberrant expression of miRNAs due to epigenetic alterations has been associated with carcinogenesis. Aimed to identify epigenetically regulated miRNAs involved in colon cancer, we analyzed DNA methylation profiles available in The Cancer Genome Atlas. One of the main hits identified was hsa-miR-3663, hypermethylated in 26% of colon cancer patients (n=286, p&amp;lt; 0.001) in comparison with complete lack of methylation in normal tissues (n=38), suggesting its potential function as a putative tumor suppressor. In order to study the role of DNA methylation controlling hsa-miR-3663, HumanMethylation450K methylation profiles were generated for a panel of colon cancer cell lines (n=10), including the HCT116-DNA methyltransferase knock-out model (DKO, double knockout of DNMT1 and DNMT3B). We found a significant correlation between methylation status of hsa-miR-3663 and expression in colon cancer cell lines. Furthermore, epigenetic regulation of hsa-miR-3663 was confirmed in HCT116 methylated cell line by restored expression upon treatment with DNA demethylating agent 5-aza-2′-deoxycytidine and in the HCT116-DKO model. In order to elucidate the function of hsa-miR-3663, we stably expressed hsa-miR-3663 in a panel of five methylated colorectal cancer cell lines (HCT116, RKO, DLD1, SW48 and SW480). Our initial functional assays revealed that hsa-miR-3663 is not involved in cell proliferation or migration. We are now performing additional assays to further study hsa-miR-3663 and its potential role in colon cancer. Note: This abstract was not presented at the meeting. Citation Format: Laia Pique, Humberto Jorge Ferrerira, Manel Esteller. Epigenetic regulation of hsa-miR-3663 in colon cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 484. doi:10.1158/1538-7445.AM2017-484
Abstract 2341:In situlabelling identifies a novel landscape of nuclear CDK2 substrates
Authors: Bruce E. Clurman, Yong Chi
Journal: Cancer Research (2017)

Abstract Cellular signal transduction pathways rely heavily on protein kinase-mediated phosphorylation events. Comprehensive identification of the physiologic targets of protein kinases is key to understanding their functions and elucidating cellular signalling pathways. Various direct and indirect approaches, combined with advanced mass spectrometry technologies, have made it possible to identify many candidate targets of a given kinase, but have also yielded many false-positive identifications, largely due to technical limitations. Identifying direct and physiological kinase targets thus remains a difficult task. We developed a mass spectrometry-based in situ approach that utilizes substrate thiophosphorylation and ATP analog-sensitive CDK2 (AS-CDK2) to identify over one hundred potential cyclin-dependent kinase 2 (CDK2) substrate in intact nuclei. More than one-third of these candidates are known CDK substrates, indicating significant enrichment for physiologic CDK2 substrates, and we also we identified and validated new CDK2 substrates. Importantly, many of these new CDK2 substrates are chromatin-associated proteins with roles in histone modification, DNA replication, and DNA repair, which likely reflects our use of AS-CDK2 within its normal nuclear context, and regulated by endogenous cyclins. These methods should be broadly applicable to the study of other kinases with complex substrate networks. Citation Format: Bruce E. Clurman, Yong Chi. In situ labelling identifies a novel landscape of nuclear CDK2 substrates [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2341. doi:10.1158/1538-7445.AM2017-2341
Abstract 4847: NME1 mediates a switch in beta integrin subunits that correlates with prolonged patient survival
Authors: M. Kathryn Leonard, Grace Snow, Marián Novak, Joseph R. McCorkle, Xiuwei H. Yang, Alexey Belkin, David M. Kaetzel
Journal: Cancer Research (2017)

Abstract Expression of the metastasis suppressor NME1 in melanoma is associated with reduced cellular motility, invasion, and metastasis, but the molecular mechanisms underlying this activity are not completely understood. Herein we report a novel mechanism through which NME1 modulates focal adhesion dynamics via regulation of integrins β1 and β3. Stable expression of NME1 significantly altered focal adhesion turnover at the cell periphery. Interestingly, over-expression of NME1 resulted in a switch from predominantly fast recycling α4β1 integrins to slower recycling αvβ3 integrins. Contrary to its regulation of other cell surface receptors, the inhibition of integrin β1 and induction of integrin β3 by NME1 was found to occur at the transcriptional level rather than through dynamin mediated endocytosis. Induction of integrin β3 required both the 3-5’ exonuclease and nucleoside diphosphate kinase (NDPK) activities of NME1, which are also required for its metastasis suppressor activities in vivo. Further suggesting that the induction of integrin β3 is involved in the metastasis suppression function of NME1, knockdown of integrin β3 significantly increased the invasion capability of cells expressing NME1 in vitro compared to control cells. Analysis of metastatic melanoma patients in the TCGA showed individuals with a 1.5x or greater increase in integrin β3 mRNA had a significantly longer overall survival times. Additionally, an inverse correlation was observed between NME1 and integrin β1 mRNA in an independent microarray of primary melanomas. The inverse correlation of NME1 and integrin β1 RNA was also a strong predictor of prolonged distant disease free and overall survival in patients with the basal-like subtype of breast carcinoma. Together, these data strongly suggest NME1 prevents metastasis of human melanoma and some types of breast cancers by altering beta integrin expression to reduce recycling of focal adhesions and, ultimately suppress of cell motility. Citation Format: M. Kathryn Leonard, Grace Snow, Marián Novak, Joseph R. McCorkle, Xiuwei H. Yang, Alexey Belkin, David M. Kaetzel. NME1 mediates a switch in beta integrin subunits that correlates with prolonged patient survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4847. doi:10.1158/1538-7445.AM2017-4847
Abstract 5643: Physical and functional interactions of exon-skipping variants of androgen receptor with the full-length counterpart
Authors: Takuma Uo, Cynthia C. Sprenger, Shihua Sun, Robert K. Bradley, Peter S. Nelson, Stephen R. Plymate
Journal: Cancer Research (2017)

Abstract The androgen receptor (AR) is arguably the critical driver of not only early but also advanced prostate cancer. The recent comprehensive splicing landscapes revealed that metastatic castration resistant prostate cancer harbors multiple forms of AR variants (AR-Vs), many of which have diverse patterns of inclusion/exclusion of exons (E4-8) corresponding to the ligand-binding domain. We had used AR-negative M12 prostate cancer cell line and recently reported characteristics of AR-Vs with respect to their subcellular localization and transcriptional activation on luciferase reporter driven by probasin-based promoter (AR2PB-luc)(1). While ARv5es is predominantly nuclear and constitutively active like well-documented ARv567es, many others are castration -induced variants are inactive. As many AR-Vs and the full-length AR (AR-FL) are co-expressed in the same cell, it is important to determine how these inactive AR-Vs interact with active AR including AR-FL. To this end, we examined two inactive AR-Vs namely v7es and v56es in relation to AR-FL. ARv7es, which skips exon 7, is predominantly localized in cytoplasm. ARv7es physically interacted with AR-FL. Moreover, nuclear accumulation of ARv7es was promoted by the addition of dihydrotestosterone (DHT) only in the presence of AR-FL, suggesting that ARv7es and AR-FL heterodimerize in the nuclear compartment. However, DHT-dependent transactivation of AR-FL was not affected by the presence of ARv7es. More specifically, in M12 cells, AR2PB-luc was transactivated by AR-FL to the similar extents either in the presence or absence of ARv7es. In addition, in doxycycline (Dox)-inducible ARv7es stable LNCaP cell line (LNCaP/ARv7es), the presence of ARv7es did not affect DHT-induced expression of endogenous PSA and NKX3.1 transcripts as well as transactivation of AR2PB-luc. In the similar setting, when we examined ARv56es which also physically interacted with AR-FL, Dox-induced expression of ARv56es in LNCaP/ARv56es was sufficient to induce expression of endogenous PSA and NKX3.1 transcripts. Further, DHT-induced expression of these transcripts was enhanced by ARv56es in LNCaP/ARv56es. Accordingly, we propose that AR-Vs display differential modes of action on AR-FL as exemplified by ARv7es as the bystander and v56es as the effector. 1. Oncogene (PMID: 27694897) Citation Format: Takuma Uo, Cynthia C. Sprenger, Shihua Sun, Robert K. Bradley, Peter S. Nelson, Stephen R. Plymate. Physical and functional interactions of exon-skipping variants of androgen receptor with the full-length counterpart [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5643. doi:10.1158/1538-7445.AM2017-5643
Abstract 4910: Eribulin rapidly impairs TGF-β signaling
Authors: Roma Kaul, April L. Risinger, Susan L. Mooberry
Journal: Cancer Research (2017)

Abstract Microtubule targeting agents (MTAs) continue to be valuable in treating breast cancer. While decades of research have shown that these drugs cause mitotic arrest in cells by suppressing the dynamic instability of microtubules, recent evidence demonstrates that the ability of MTAs to disrupt the microtubule-dependent transport of key signaling components in interphase cells likely contributes to their anticancer actions. Cell signaling messages are relayed by proteins that organize or scaffold signaling hubs. These signaling nodes facilitate the complex organization and coordination of multiple signaling partners. NEDD9 is a member of the CAS scaffold family and it has been shown to coordinate TGF-β signaling, a driver of oncogenesis and epithelial-to-mesenchymal transition (EMT). Ligand-mediated stimulation of TGF-β receptors leads to the activation of downstream canonical and non-canonical signaling pathways. These pathways collectively induce the expression of Snail and Slug, key transcriptional-repressors that promote EMT. We tested the hypothesis that a short-term treatment of breast cancer cells with eribulin or 3 other clinically relevant MTAs would differentially disrupt interphase microtubules and alter TGF-β-dependent signaling. BT-549 cells were treated for 2 h with concentrations of MTAs that are clinically relevant and cause maximum disruption of the interphase microtubule network; 100 nM was used for the destabilizers, eribulin and vinorelbine and 1 µM was used for the stabilizers, paclitaxel and ixabepilone. The results showed that eribulin and vinorelbine significantly inhibited TGF-β- induced expression of Snail and Slug. The microtubule stabilizers had no effect on Snail and Slug expression following TGF-β stimulation. Further studies evaluated whether NEDD9 contributes to the downregulation of Snail and Slug. Co-immunoprecipitation and knockdown studies suggest that eribulin impairs the ability of NEDD9 to scaffold TGF-β signaling partners, thus inhibiting downstream transcriptional signaling. Consistent with the ability of eribulin to reverse EMT in experimental models within 7 days, this study begins to shed light on the mechanisms underlying its action. Funding for this work was provided by Eisai Inc. Citation Format: Roma Kaul, April L. Risinger, Susan L. Mooberry. Eribulin rapidly impairs TGF-β signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4910. doi:10.1158/1538-7445.AM2017-4910