bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract LB-311: Development of mutant-specific small molecule inhibitors of K-Ras.
Authors: Ostrem Jonathan M. , Peters Ulf , Ren Pingda , Liu Yi , Wells James A. , Shokat Kevan M. 
Published: August 2014

Abstract
Activating mutations in K-Ras are among the most common lesions found in human cancer, and such mutations are generally associated with poor prognosis. Despite numerous efforts in academia and industry, small molecule inhibitors that directly target K-Ras remain elusive. Even more highly desired are molecules that selectively target mutant K-Ras while sparing the wild type protein. We have used a fragment-based screen to discover oncogenic mutant-specific inhibitors of K-Ras. Crystallographic studies with multiple inhibitors in complex with K-Ras reveal that the compounds bind in a novel hydrophobic pocket that is not apparent in any published crystal structure of Ras. These inhibitors disrupt the conformations of Switch I and Switch II, domains that are essential for the association and activation of downstream signaling partners. Our medicinal chemistry effort has greatly improved potency, showing that this pocket is particularly amenable to chemical optimization. In vitro biochemical characterization of these inhibitors confirms that they block Ras function. Our discovery of a new druggable pocket in K-Ras, and a set of inhibitors that bind to it in a mutant-specific fashion, provides a promising new avenue for the direct pharmacological inhibition of oncogenic Ras.
Citation Format: Jonathan M. Ostrem, Ulf Peters, Pingda Ren, Yi Liu, James A. Wells, Kevan M. Shokat. Development of mutant-specific small molecule inhibitors of K-Ras. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-311. doi:10.1158/1538-7445.AM2013-LB-311
Abstract LB-317: Potent in vivo pharmacology of AZD9150, a next-generation, constrained ethyl-modified antisense oligonucleotide targeting STAT3 in multiple preclinical cancer models.
Authors: Kim Youngsoo , Hsu Jeff , Zhou Tianyuan , Zhang Nancy , Woessner Richard , Nadella Murali VP , Lawson Deborah , Reimer Corinne , He Guobin , Schmidt Joanna , Xiao Xiaokun , Greenlee Sarah , Bhattacharjee Gourab , Hung Gene , Monia Brett P. , MacLeod A. Robert 
Published: August 2014

Abstract
Next generation sequencing technologies have greatly expanded our understanding of cancer genomes, epigenomes and transcriptomes. This knowledge, however, has not yet been effectively translated into improved cancer therapeutics, partly due to the inability of available therapeutic modalities to target the most promising cancer driver pathways. In contrast to other therapeutic approaches, the druggable universe is not limited with antisense technology as inhibitors can be rationally designed based on sequence information alone. Recent human clinical data has demonstrated potent activity of systemically-administered, unformulated, antisense oligonucleotides (ASOs) when targeted to liver expressed genes. However, robust activity in extra-heptatic tissues and tumors has been limited with existing ASO chemistries. Here we evaluate the activity of high affinity next generation (constrained ethyl) ASOs in extrahepatic tissues and tumors of multiple preclinical cancer models including spontaneous tumors, human tumor xenografts and several primary patient-derived xenograft models. As a test case we employed next generation ASOs to inhibit the difficult to drug transcription factor STAT3. ASOs targeting mouse STAT3 sequences and the human-specific STAT3 ASO (AZD9150) demonstrate potent and selective inhibition of target RNA and protein levels in tumors and tumor-associated stromal cells of a broad range of cancer models, resulting in strong antitumor activity in several models. These findings suggest that next generation ASO technology is now poised to become a key therapeutic modality to bridge the pharmacogenomic divide in cancer drug discovery. The STAT3 ASO inhibitor, AZD9150 is currently in human clinical studies including patients with lymphomas.
Citation Format: Youngsoo Kim, Jeff Hsu, Tianyuan Zhou, Nancy Zhang, Richard Woessner, Murali VP Nadella, Deborah Lawson, Corinne Reimer, Guobin He, Joanna Schmidt, Xiaokun Xiao, Sarah Greenlee, Gourab Bhattacharjee, Gene Hung, Brett P. Monia, A. Robert MacLeod. Potent in vivo pharmacology of AZD9150, a next-generation, constrained ethyl-modified antisense oligonucleotide targeting STAT3 in multiple preclinical cancer models. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-317. doi:10.1158/1538-7445.AM2013-LB-317
Abstract LB-323: Deficiency of Kruppel-like factor KLF4 in mammary tumor cells resulted in inhibited tumor growth and pulmonary metastasis accompanied by compromised recruitment of myeloid-derived suppressor cells.
Authors: Yu Fang , Fan Daping , Ai Walden 
Published: August 2014

Abstract
Increasing evidence indicates that myeloid-derived suppressor cells (MDSCs) negatively regulate immune responses during tumor progression, inflammation and infection. However, the underlying molecular mechanisms of their development and mobilization remain to be fully delineated. Kruppel-like factor KLF4 is a transcription factor that has an oncogenic function in breast cancer development, but its function in tumor microenvironment, a critical component for tumorigenesis, has not been examined. By using a spontaneously metastatic 4T1 breast cancer mouse model and an immunodeficient NOD/SCID mouse model, we demonstrated that KLF4 knockdown delayed tumor development and inhibited pulmonary metastasis, which was accompanied by decreased accumulation of MDSCs in bone marrow, spleens and primary tumors. Mechanistically, we found that KLF4 knockdown resulted in a significant decrease of circulating GM-CSF, an important cytokine for MDSC biology. Consistently, recombinant GM-CSF restored the frequency of MDSCs in purified bone marrow cells incubated with conditioned medium from KLF4 deficient cells. In addition, we identified CXCL5 as a critical mediator to enhance the expression and function of GM-CSF. Reduced CXCL5 expression by KLF4 knockdown in primary tumors and breast cancer cells was correlated with a decreased GM-CSF expression in our mouse models. Finally, we found that CXCL5/CXCR2 axis facilitated MDSC migration and that anti-GM-CSF antibodies neutralized CXCL5-induced accumulation of MDSCs. Taken together, our data suggest that KLF4 modulates maintenance of MDSCs in bone marrow by inducing GM-CSF production via CXCL5 and regulates recruitment of MDSCs into the primary tumors through the CXCL5/CXCR2 axis, both of which contribute to KLF4-mediated mammary tumor development.
Citation Format: Fang Yu, Daping Fan, Walden Ai. Deficiency of Kruppel-like factor KLF4 in mammary tumor cells resulted in inhibited tumor growth and pulmonary metastasis accompanied by compromised recruitment of myeloid-derived suppressor cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-323. doi:10.1158/1538-7445.AM2013-LB-323
Abstract LB-324: The response of infiltrating and resident macrophages to melanoma challenge in the mouse lung: Involvement of the CC-chemokine axis in the recruitment of pro-tumoral macrophages.
Authors: Tapmeier Thomas T. , Gal Annamaria , Muschel Ruth J. 
Published: August 2014

Abstract
In a pulmonary metastasis model using B16F10 melanoma, we found monocyte/macrophage infiltration gradually increasing in the course of metastatic progression. The gene expression pattern of the infiltrating macrophages revealed an early (d3) inflammatory response that shifted to a tumor-promoting late response (d21). The pro-tumoral expression pattern was characterized by Arg1 and elevated expression of Ccl2, Vcam1, Vegfa, Stab1, Lyve1 and Ptgs2. In contrast, while enhancing their anti-inflammatory phenotype, resident lung (alveolar) macrophages also expressed pro-inflammatory genes, notably Il12b.
We found at least three chemokine receptors involved in the recruitment of macrophages into the metastatic lung: CCR1, CCR2 and CCR5. The B16F10 cells secreted large quantities of RANTES which in turn activates CCR1 and CCR5, and thus contribute to macrophage chemotaxis. Infiltrating monocytes/macrophages, as well as alveolar macrophages, revealed an increased chemokine expression level in response to tumor challenge. These chemokines included the ligands for CCR1 and CCR5, Mip1α and Mip1β, thus providing a constant means of further macrophage recruitment. Interestingly, the expression of the CCR2 ligand, CCL2, was found strikingly increased by infiltrating monocytes/ macrophages, thus ensuring a positive feed-back loop for macrophage recruitment.
In order to explore the involvement of CC chemokine receptors in pulmonary metastasis, we treated the mice with antagonists against CCR1, CCR5 and CCR2 after i.v. B16F10 challenge. The CCR1 and CCR5 antagonist treatments resulted in a 20% decrease in the number of lung colonies each. FACS analysis of the B16F10 colony bearing lungs revealed a distribution of macrophage subsets quite different from untreated lungs, highlighting the importance of CC-chemokine receptors in the recruitment of pro-tumoral macrophages. The effect of a CCR2 antagonist on lung colony formation will be discussed, together with its effect on the phenotype of macrophage subpopulations.
Citation Format: Thomas T. Tapmeier, Annamaria Gal, Ruth J. Muschel. The response of infiltrating and resident macrophages to melanoma challenge in the mouse lung: Involvement of the CC-chemokine axis in the recruitment of pro-tumoral macrophages. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-324. doi:10.1158/1538-7445.AM2013-LB-324
Abstract LB-335: Autologous whole-tumor antigen vaccination in combination with adoptive T cell therapy for patients with recurrent ovarian cancer.
Authors: Kandalaft Lana E. , Tanyi Janos , Chiang Cheryl , Powell Daniel , coukos George 
Published: August 2014

Abstract
Novel therapeutic strategies are warranted in recurrent ovarian cancer. We report two independent consecutive studies of combinatorial immunotherapy comprising dendritic cell (DC)-based autologous whole tumor antigen vaccination in combination with antiangiogenesis therapy. 31 patients with recurrent progressive stage III and IV ovarian cancer with available tumor lysate from secondary debulking surgery enrolled in two different studies. First 6 underwent priming with intravenous bevacizumab and oral metronomic cyclophosphamide followed by vaccination with an autologous DC preparation pulsed with freeze-thaw autologous tumor lysate while the other 25 underwent vaccination with an enhanced vaccine where autologous DCs were loaded with HOCl-oxidized autologous tumor lysate administered intranodally every 2 weeks in combination with intravenous bevacizumab. Both studies were followed by lymphodepletion and transfer of autologous vaccine-primed, ex vivo CD3/CD28-costimulated peripheral blood T-cells, in combination with antiangiogenesis therapy and vaccination. Feasibility, safety, and biological and clinical efficacy were evaluated. Eleven subjects have completed vaccination and T cell transfer to date, while twenty-three additional subjects completed vaccination only. Vaccination was well tolerated and elicited tumor-specific T cell responses against various ovarian tumor antigen in both studies and clinical benefit of 65% correlated with the immune response with some experiencing prolonged progression free survival. Following lymphodepletion, adoptive transfer of vaccine-primed T-cells was well tolerated and resulted in durable reduction of T-regulatory cells and restoration of vaccine-induced antitumor immunity in patients who experienced clinical benefit. One patient exhibited no evidence of disease at end of study. Stable disease was observed in 8 subjects to date. Data on additional patients will be presented at the meeting. Our results suggest the use of combinatorial cellular immunotherapy comprising DC vaccination with whole tumor antigen and adoptive lymphocyte transfer using tumor antigen-specific T cells for the treatment of patients with recurrent ovarian cancer is promising yet warrants further investigation.
Citation Format: Lana E. Kandalaft, Janos Tanyi, Cheryl Chiang, Daniel Powell, George coukos. Autologous whole-tumor antigen vaccination in combination with adoptive T cell therapy for patients with recurrent ovarian cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-335. doi:10.1158/1538-7445.AM2013-LB-335
Abstract LB-349: Tumor associated macrophages mediate gemcitabine resistance of pancreatic adenocarcinoma by upregulating cytidine deaminase.
Authors: Binenboum Yoav , Weissman Noam , Kerlin Yakov , Shabtai Ayelet , Amit Moran , Gil Ziv 
Published: August 2014

Abstract
Resistance to pharmacologic agents used in chemotherapy is a common phenomenon in most human carcinomas. Pancreatic ductal adenocarcinoma (PDA) is such a tumor, which is resistant to almost all drugs, including gemcitabine, a new nucleoside analog used as first-line treatment. For this reason the poor survival of patients with PDA have not change much during the last 4 decades. Recent data indicated that tumor-associated macrophages (TAMs) which are abundant in the microenvironment of several tumors, including PDA, secrete pro-tumorigenic factors which contribute to cancer progression and dissemination. In this study, we show for the first time that TAMs can also induce chemoresistance of PDA by reducing gemcitabine-induced apoptosis. Macrophages co-cultures with cancer cells or TAMs conditioned medium significantly reduced the levels of cleaved caspase-3 and caspase-3 during gemcitabine treatment. An in vivo PDA model of CCR2-deficient mice, which have reduced macrophage recruitment and activation, demonstrated improved response to gemcitabine compared to wild-types. Similarly, inhibition of monocytes/macrophages trafficking by a CSF1-receptors antagonist augmented the effect of gemcitabine in a transgenic mouse model of PDA that was resistant to gemcitabine alone. Analysis of multiple proteins involved in gemcitabine delivery and metabolism revealed that TAMs induced upregulation of cytidine deaminase (CDA), the enzyme that metabolizes the active form of the drug. Decreasing of CDA expression by PDA cells blocked the protective effect of TAMs against gemcitabine. Taken together, our results identify a paracrine effect of TAMs on PDA cells, which mediates acquire resistance of cancer cells to chemotherapy. Modulation of macrophage trafficking or inhibition of CDA may offer a new strategy for augmenting the response of PDA to chemotherapy.
Citation Format: Yoav Binenboum, Noam Weissman, Yakov Kerlin, Ayelet Shabtai, Moran Amit, Ziv Gil. Tumor associated macrophages mediate gemcitabine resistance of pancreatic adenocarcinoma by upregulating cytidine deaminase. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-349. doi:10.1158/1538-7445.AM2013-LB-349
Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.
Abstract LB-359: Inhibition of DNA repair by the dual PI3K/mTOR inhibitor NVP-BEZ235 as a novel radiosensitization strategy for glioblastoma.
Authors: Alcazar Carlos Gil Del , Gillam Molly , Tomimatsu Nozomi , Gao Xiaohuan , Mukherjee Bipasha , Burma Sandeep 
Published: August 2014

Abstract
Glioblastomas (GBM) are deadly brain tumors with extremely poor prognosis. The standard of care for GBM is tumor resection followed by treatment with ionizing radiation (IR) and the DNA alkylating agent temozolomide. As GBMs are highly radioresistant, it is crucial to identify effective radiosensitizers for improving therapeutic outcome. We find that NVP-BEZ235, a dual PI3K/mTOR inhibitor that is in clinical trials, potently inhibits both ATM and DNA-PKcs, the two major kinases that respond to IR-induced DNA double-strand breaks (DSBs). Consequently, this drug blocks non-homologous end joining (NHEJ) as well as homologous recombination (HR), the two major pathways of DSB repair. We find that low concentrations of NVP-BEZ235 (100 nM) can block DSB repair in a panel of human GBM lines resulting in significant radiosensitization. This radiosensitizing effect is more potent than that seen with much higher concentrations (10 μm) of current inhibitors of DNA-PKcs or ATM that are being optimized for clinical testing. In order to examine the effects of NVP-BEZ235 in vivo, we sub-cutaneously injected mice with radioresistant U87 glioma cells ectopically expressing EGFRvIII and treated with clinically-relevant doses of the drug. We find that NVP-BEZ235 blocks the activation of both DNA-PKcs and ATM in irradiated tumors resulting in significant attenuation of DSB repair. Tumors treated with a combination of IR and NVP-BEZ235 exhibit elevated DSBs and reduced Ki67 positivity compared to tumors treated with only IR or NVP-BEZ235. Consequently, a combination of IR and NVP-BEZ235 results in dramatic inhibition of tumor growth, in contrast to almost no inhibition with either treatment modality alone. Finally, we established that NVP-BEZ235 can cross the blood-brain barrier and therefore examined its effectiveness in an orthotopic brain tumor model. We find that NVP-BEZ235 given with IR can attenuate the growth of intracranial tumors generated from U87-EGFRvIII cells, thereby extending survival of tumor-bearing mice. Importantly, NVP-BEZ235 also sensitizes subcutaneous and intracranial tumors to temozolomide by attenuating the repair of secondary (replication-associated) DSBs that are generated upon temozolomide treatment. In sum, this study provides support for the potential use of NVP-BEZ235 as a radio- and chemo-sensitizer for improving the outcome of GBM therapy.
Citation Format: Carlos Gil Del Alcazar, Molly Gillam, Nozomi Tomimatsu, Xiaohuan Gao, Bipasha Mukherjee, Sandeep Burma. Inhibition of DNA repair by the dual PI3K/mTOR inhibitor NVP-BEZ235 as a novel radiosensitization strategy for glioblastoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-359. doi:10.1158/1538-7445.AM2013-LB-359
Abstract LB-38: VPS34 lipid kinase activity is positively regulated by Src phosphorylation and is required for Src-mediated cellular transformation.
Authors: Hirsch Dianne S. , Shen Yi , Dokmanovic Milos , Wu Wen Jin 
Published: August 2014

Abstract
VPS34 is a phosphatidylinositol 3-kinase (PI3K) that catalyzes phosphorylation of phosphatidylinositol. In response to nutrients, VPS34 contributes to the activation of mTOR/S6K1 signaling which regulates proliferation, protein synthesis, and cell survival. Intracellular mechanisms leading to VPS34 activation are just beginning to be elucidated. Src is a non-receptor tyrosine kinase that signals downstream of numerous pathways to regulate cell proliferation, survival, and cancer metastasis. Here, we report that Src directly phosphorylates VPS34 leading to activation of VPS34 lipid kinase activity, and that VPS34 lipid kinase activity is required for Src-mediated cellular transformation. Silencing VPS34 specifically inhibits Src-Y527F-induced colony formation in soft agar, but not Ras-G12V-induced colony formation. We have identified two novel VPS34 mutations, which either eliminate lipid kinase activity (KD mutant) or reduce tyrosine phosphorylation (Y231F mutant) by Src-Y527F. When VPS34-KD is stably expressed in Src-Y527F-transformed cells, proliferation and anchorage independent growth are significantly inhibited. Additionally, stable expression of VPS34-KD causes an increased number of binucleate and multinucleate cells, suggesting that VPS34 kinase activity is also required for cytokinesis. Stable expression of VPS34-Y231F in Src-Y527F transformed cells also reduces colony formation. We additionally found that VPS34 protein levels and tyrosine phosphorylation correlate with the tumorigenic activity of breast cancer cell lines. Together these data suggest that Src to VPS34 signaling may contribute to the development and progression of human cancers.
Citation Format: Dianne S. Hirsch, Yi Shen, Milos Dokmanovic, Wen Jin Wu. VPS34 lipid kinase activity is positively regulated by Src phosphorylation and is required for Src-mediated cellular transformation. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-38. doi:10.1158/1538-7445.AM2013-LB-38
Abstract LB-41: Rictor undergoes GSK3-dependent, FBXW7-mediated ubiquitination and proteasomal degradation.
Authors: Koo Junghui , Wu Xiayun , Yue Ping , Mao Zixu , Khuri Fadlo R. , Sun Shi-Yong 
Published: August 2014

Abstract
Rictor directly interacts with mTOR and other proteins to form an important complex (i.e., mTOR complex 2, mTORC2) that plays critical role in regulation of cellular homeostasis primarily by phosphorylating some AGC kinases such as Akt, PKC and SGK. Moreover, rictor also exerts biological functions such as regulation of protein degradation by interacting with other proteins independent of mTORC2. However the degradation of rictor itself and underlying mechanism are largely unknown and thus are the focuses of this study. We found that inhibition of proteasome with the proteasome inhibitor MG132 increased rictor levels accompanied with elevated rictor ubiquitination. Consistently inhibition of F-box and WD repeat domain-containing 7 (FBXW7; also known as FBW7 and CDC4) with various genetic means including knockdown, knockout and enforced expression of a dominant-negative mutant inhibited rictor ubiquitination and increased rictor levels, whereas enforced expression of FBXW7 decreased rictor stability and levels. Moreover, we detected an interaction between FBXW7 and rictor by immunoprecipitation. Hence, rictor is degraded through a FBXW7-mediated ubiquitination/proteasome mechanism. This process is dependent on GSK3 because GSK3 was associated with rictor and directly phosphorylated the Thr1695 site in a putative CPD motif of rictor; mutation of this site impaired the interaction between rictor and FBXW7, decreased rictor ubiquitination and increased rictor stability. Collectively we conclude that rictor undergoes GSK3-dependent, FBXW7-mediated ubiquitination and proteasomal degradation. (J Koo and X Wu contributed equally to this work. This study was supported by Georgia Cancer Coalition Distinguished Cancer Scholar award and NIH R01 CA118450, R01 CA160522 and P01 CA116676. FR Khuri and S-Y Sun are Georgia Cancer Coalition Distinguished Cancer Scholars.)
Citation Format: Junghui Koo, Xiayun Wu, Ping Yue, Zixu Mao, Fadlo R. Khuri, Shi-Yong Sun. Rictor undergoes GSK3-dependent, FBXW7-mediated ubiquitination and proteasomal degradation. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-41. doi:10.1158/1538-7445.AM2013-LB-41