bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1077: Extra-virgin olive oil Met inhibitor oleocanthal-lapatinib: a novel synergistic combination for HER2-dependent breast malignancies
Authors: Siddique Abu Bakar , Ebrahim Hassan Y. , Akl Mohamed R. , Mohyeldin Mohamed M. , Sayed Khalid A. El
Published: July 2017

Breast cancer (BC) is the most commonly diagnosed cancer in women, claiming the lives of hundreds of thousands of women each year. The Mediterranean diet is known to reduce BC and colon cancer incidence. Extra-virgin olive oil (EVOO) represents a main ingredient in this diet. The EVOO-derived (-)-oleocanthal was shown to target the Receptor tyrosine kinases (RTK) c-Met. Oleocanthal exerted potent in-vivo efficacy in an orthotopic athymic nude mouse breast cancer xenograft model much greater than its modest in-vitro potency. Dysregulation of RTKs, specifically EGFR/HER-2 pathways, correlates with poor prognosis and more aggressive breast cancer phenotypes. Dysregulation of hepatocyte growth factor (HGF) and its receptor c Met correlates with aggressive proliferation, invasive character, and pathological motility. c-Met amplification correlates with escape from the anticancer effects of EGFR/HER2 inhibitors and cetuximab. (-)-Oleocanthal (OC) is a naturally occurring phenolic secoiridoid from EVOO showed significant in vivo activity against invasive breast cancers through targeting HGF/Met axis. The Dual EGFR/HER-2 inhibitor lapatinib (LP) has already been in clinical practice for HER2-amplified breast cancer, which occasionally develops resistance through c-Met upregulation. Lapatinib’s therapeutic dose induced significant hepatotoxicity. The combined use of OC and LP was hypothesized not only for therapeutic synergy but also to notably reduce LP’s effective doses and therefore minimize its hepatotoxicity. Combined treatment of subeffective doses of lapatinib and OC caused significant in vitro and in vivo synergistic antiproliferative effects against the HER-2-dependent BT-474 and SKBR-3 BC cells. Interestingly, OC induced 4-fold lapatinib dose reduction index with improved potency. Protein microarray and Western blot analyses of OC-LP combination treatments synergistically reduced EGFR, HER-2, FAK, JAK1, MEK, and c-Met activation. These results propose OC use as dietary supplement to synergize the chemotherapeutic effects of LP, reduce its therapeutic dose to ¼ and therefore can minimize its morbidity. Combinatorial inhibition of c-Met-HER-2-EGFR is an effective strategy for the control of HER-2 positive breast cancer. This study was supported by NIH/NCI project 1R15CA167475-01.

Citation Format: Abu Bakar Siddique, Hassan Y. Ebrahim, Mohamed R. Akl, Mohamed M. Mohyeldin, Khalid A. El Sayed. Extra-virgin olive oil Met inhibitor oleocanthal-lapatinib: a novel synergistic combination for HER2-dependent breast malignancies [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 1077. doi:10.1158/1538-7445.AM2017-1077
Abstract 1081: APC regulation of breast cancer therapeutic resistance
Authors: Arnason Anne , VanKlompenberg Monica , Prosperi Jenifer R.
Published: July 2017

Resistance to chemotherapy is one of the leading causes of death from breast cancer. Our lab discovered that Adenomatous Polyposis Coli (APC) loss in breast cancer cells results in an elevation of tumor-initiating cells (TICs) and resistance to chemotherapy-induced apoptosis. Given that TICs are often most resistant to standard chemotherapeutic compounds, we sought to understand the mechanism responsible for APC-mediated TIC enhancement. Our hypothesis is that the molecular mechanism involved in chemotherapeutic resistance parallels that promoting the TICs. APC-mutant cells have amplified activation of signal transducer and activator of transcription 3 (STAT3). Interestingly, inhibition of STAT3 with a small molecule inhibitor A69 decreases the TIC population and restores drug sensitivity. Studies are ongoing in the laboratory to investigate other molecular signaling pathways involved in APC-mediated enhanced TIC population and therapy resistance. These data have begun to reveal the molecular mechanisms of APC loss in breast cancer that can guide future treatment plans to counteract chemotherapeutic resistance.

Note: This abstract was not presented at the meeting.

Citation Format: Anne Arnason, Monica VanKlompenberg, Jenifer R. Prosperi. APC regulation of breast cancer therapeutic resistance [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 1081. doi:10.1158/1538-7445.AM2017-1081
Abstract 1083: Synergistic drug combination prediction through drug differential dependency network analysis
Authors: Kim Seungchan , Speyer Gil , Dhruv Harshil , Kiefer Jeff , Berens Michael
Published: July 2017

In an effort to discover strategies which identify effective drug combinations, we analyzed 39 of the 480 compounds screened in the Cancer Therapeutics Response Portal (CTRP) where combinations of two compounds were tested against 860 cancer cell lines; this enabled a comparison of the drug sensitivity of the combinations versus that of the individual compounds. More than half of the drug combinations (n=21) did not significantly improve the drug sensitivity, compared to individual compounds alone. In fact, some of the combinations showed reduced drug sensitivity. In EDDY-CTRP* analysis, the Cancer Cell Line Encyclopedia (CCLE) RNAseq data and CTRP compound response measurements were analyzed to discover both 1) pathways enriched with differential dependencies between sensitive and non-sensitive cell lines for each compound and 2) the mediators of cell line response to a drug. A mediator is a gene in a pathway that plays a significantly different role between sensitive and non-sensitive conditions. The significance is assessed for either essentiality, measured as a node’s centrality change, or specificity, measured as the difference in condition specific edges. These drug-pathway-mediator connections are predicted to reveal crucial molecular determinants of drug sensitivity that otherwise are hidden in the complexities of the molecular networks of the cell (Speyer et al., PSB 22:497-508, 2017). We further investigated whether mediators identified for single compounds could predict sensitivity to drug combinations. This analysis revealed that if two single compounds share the same specificity mediators, i.e. the genes with the most significant re-wiring of gene dependencies between sensitive and non-sensitive cell lines, combination of these two compounds correlate with improved sensitivity. The converse was also found: compounds that do not share mediators rarely show synergy. Further analysis and empirical testing of predicted combinations promises to prioritize synergistic drug combinations. We believe that this methodology may predict synergistic drug combinations from cancer cell line drug screening data. Supported by NIH U01CA168397.

*available at http://biocomputing.tgen.org/software/EDDY/CTRP

Citation Format: Seungchan Kim, Gil Speyer, Harshil Dhruv, Jeff Kiefer, Michael Berens. Synergistic drug combination prediction through drug differential dependency network analysis [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 1083. doi:10.1158/1538-7445.AM2017-1083
Abstract 1104: Novel specific RTK targeting of EGFR/FAK axis in glioblastoma invasion
Authors: Vengoji Raghupathy , Rachagani Satyanarayana , Gupta Suprit , Mallya Kavita , Jain Maneesh , Ponnusamy Moorthy , Batra Surinder , Shonka Nicole
Published: July 2017

Background: Glioblastoma (GBM) is the most aggressive primary brain tumor with a median survival rate of 14.6 months. Currently, the first-line treatment includes surgical resection, chemoradiation, and adjuvant chemotherapy with temozolomide. However, GBM recurs most often within 6.9 months. Receptor tyrosine kinases are dysregulated in GBM, with epidermal growth factor receptor (EGFR) representing 57.4% of the deleted/mutated GBM. In addition, 30 - 40% of GBM patients with EGFR amplification carry an oncogenic gene rearrangement EGFR variant III (EGFRvIII) which is constitutively active. Yet most EGFR inhibitors have shown very little clinical efficacy in GBM.

Methods: Afatinib, blood-brain barrier penetrant pan-EGFR inhibitor, covalently binds and irreversibly inhibits signaling from EGFR. Afatinib also persistently inhibits ErbB homo and hetero-dimers. Using GBM cell lines U87MG and U87MG transfected with wild type EGFR, EGFRvIII and EGFRvIII with dead kinase domain, we evaluated the efficacy of afatinib alone and in combination with temozolomide.

Results: Afatinib treatment resulted in a dose dependent decrease in the proliferation of U87MG cells transfected with EGFRvIII. The IC50 value for this cell line is 2µM (afatinib). 50µM temozolomide inhibited cell proliferation by 50%. We evaluated the combinational efficacy of IC25 of both. Afatinib effectively blocked EGFR signaling even 72 hours after treatment in the U87MG cell line transfected with either wild type EGFR or EGFRvIII. This was evidenced by decreased phosphorylation of EGFR (Tyr 1068) and its downstream signaling. Focal adhesion kinase (FAK) signaling in EGFRvIII expressing cells, largely responsible for the invasiveness of GBM, was abolished by afatinib. Furthermore, treatment with afatinib and temozolomide significantly decreased the in vitro tumorigenicity (anchorage dependent growth - colony formation assay as well as anchorage independent growth - soft agar assay) of EGFRvIII expressing GBM cells.

Conclusion: Altogether, these results support synergistic efficacy of afatinib and temozolomide in EGFRvIII expressing GBM.

Citation Format: Raghupathy Vengoji, Satyanarayana Rachagani, Suprit Gupta, Kavita Mallya, Maneesh Jain, Moorthy Ponnusamy, Surinder Batra, Nicole Shonka. Novel specific RTK targeting of EGFR/FAK axis in glioblastoma invasion [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 1104. doi:10.1158/1538-7445.AM2017-1104
Abstract 111: Targeting STAT3 and telomerase for the treatment of colorectal cancer
Authors: Chung Seyung , Okobi Quincy , Adekoya Debbie , Vadgama Jaydutt
Published: July 2017

There is an increasing evidence of pro-inflammatory cytokines involvement in cancer development. Here, we found that two cytokines, IL-6 and TNF-α, induced colorectal cancer cells more active and invasive. Combined treatments of IL-6 and TNF-α phosphorylated transcription factors STAT3 in a synergistic manner. STAT3 and NF-κB physically interacted upon cytokine stimulation. Similarly, STAT1 hetero-dimerized with STAT3 and the binding affinity was enhanced with cytokine treatments. STAT3 bound the promoter region of human telomerase reverse transcriptase (hTERT), and IL-6 and TNF-α stimulation further enhanced this STAT3 binding affinity. Withaferin A, an anti-inflammatory steroidal lactone, inhibited the IL-6 and TNF-α induced cancer cell invasiveness and decreased colonosphere formation. Notably, withaferin A inhibited STAT3 phosphorylation and abolished the STAT3 and NF-κB interactions. STAT3 binding to hTERT promoter was inhibited and telomerase activity was decreased with the withaferin A treatments. Taken together, pro-inflammatory cytokines induced-cancer cell invasiveness is mediated by STAT3 regulated mechanism in colorectal cancer cells. Our study suggests the novel natural compound therapy for the metastatic colorectal cancer in clinical settings.

Citation Format: Seyung Chung, Quincy Okobi, Debbie Adekoya, Jaydutt Vadgama. Targeting STAT3 and telomerase for the treatment of colorectal 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 111. doi:10.1158/1538-7445.AM2017-111
Abstract 1112: Forced reduction of DSS1, a member of TREX2 complex, highly sensitizes chemotherapy to breast cancer cells in a BRCA2-independent manner
Authors: Kuwahara Kazuhiko , Gondo Naomi , Rezano Andri , Zhang Zhenhuan , Hato Yukari , Kuzushima Kiyotaka , Iwata Hiroji , Toyama Tatsuya , Kondo Eisaku
Published: July 2017

[Introduction] DSS1 (deleted in split-hand/split-foot malformation 1) was originally identified as a BRCA2-associated/stabilizing protein. By comparison of DSS1 mRNA level, we reported that the high DSS1 expression groups in breast cancer patients showed worse prognosis in relapse-free survival (RFS); however, DSS1 expression per se was not correlated with other clinical parameters including cellular proliferation or tumor grade, suggesting that the level of DSS1 affected the sensitivity of DNA-damage agents in breast cancer cells (Rezano et al., 2013). It still remains unclear why the expression level of DSS1 is associated with chemosensitivity, because DSS1 has multifunctional properties regulating homologous recombination and RNA-mediated genomic stability. In this study, we investigated if the effect of DSS1 in chemosensitivity is influenced by two representative DSS1-associated molecules, BRCA2 and PCID2.

[Methods] We established MCF7 overexpressing DSS1 (MCF7/DSS1) by retroviral transfection. DSS1, BRCA2, or PCID2 knockdown in MCF7 was performed using siRNA transfection. The susceptibility to the cytotoxic chemotherapy such as doxorubicin and paclitaxel in breast cancer cells was evaluated by flow cytometry to detect apoptosis and colony assay. In addition, we compared patient survival by dividing patients into high or low expression group of BRCA2 or PCID2 using cohort studies.

[Results] BRCA2 depletion in MCF7/DSS1 did not alter the chemoresistance. Although DSS1 knockdown induced the downregulation of BRCA2, direct depletion of BRCA2 did not show marginal effect to chemosensitivity, suggesting that the enhancement of chemosensitivity by DSS1 knockdown was not related to BRCA2 expression. Importantly, over- and under-expression of PCID2 induced similar effect to chemosensitivity compared to those of DSS1. There was a trend that high PCID2 expression group in breast cancer patients showed worse prognosis in RFS.

[Conclusion] DSS1 could be a molecular target to increase chemosensitivity, which is independent of BRCA2 expression. Rather, the transcription-coupled DNA damage induced by impaired TREX2 complex might be associated with induction of chemosensitivity.

Citation Format: Kazuhiko Kuwahara, Naomi Gondo, Andri Rezano, Zhenhuan Zhang, Yukari Hato, Kiyotaka Kuzushima, Hiroji Iwata, Tatsuya Toyama, Eisaku Kondo. Forced reduction of DSS1, a member of TREX2 complex, highly sensitizes chemotherapy to breast cancer cells in a BRCA2-independent manner [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 1112. doi:10.1158/1538-7445.AM2017-1112
Abstract 1118: Synthetic lethality of CDK12 inhibition in tumors with EWS/FLI rearrangements
Authors: Balboni Amanda L. , Stolte Bjorn , Conway Amy Saur , Alexe Gabriela , Wang Emily Jue , Kwiatkowski Nicholas , Zhang Tinghu , Abraham Brian J. , Kalev Peter , Chowdhury Dipanjan , Benes Cyril H. , Young Richard A. , Gray Nathanael S. , Stegmaier Kimberly
Published: July 2017

THZ1 is a potent, covalent inhibitor of the transcriptional CDKs, CDK7/12/13. Chemical genomic profiling of THZ1 across >1,000 diverse cancer cell lines revealed that EWS/FLI- rearranged Ewing sarcoma cells were remarkably sensitive to this molecule. We demonstrated that THZ1 inhibits the phosphorylation of the C-terminal domain of RNA Polymerase II, decreased colony formation capacity, and induced apoptosis in a dose-dependent manner in Ewing sarcoma cell lines. Using selective CDK7 and CDK12/13 inhibitors, we revealed that the primary target of THZ1 in Ewing sarcoma is CDK12/13. Genetic suppression of CDK12, but not CDK13, induced strong anti-viability effects, confirming CDK12 as the primary target. Treatment of Ewing sarcoma cell lines with THZ531, a novel CDK12/13 selective inhibitor, preferentially repressed genes involved in DNA damage repair. Additionally, suppression of EWS/FLI rendered Ewing sarcoma cells resistant to THZ531 and partially rescued the anti-viability effects of CDK12 knockdown. These results suggest that EWS/FLI imparts vulnerability to DNA damage repair inhibition and implicate a synthetic lethal relationship between the tumor-specific expression of EWS/FLI and CDK12 inhibition. Furthermore, we demonstrated that CDK12 and PARP inhibitors are highly synergistic in vitro, inducing widespread yH2AX foci formation. Interestingly, THZ531 impairs the ability of the PARP inhibitor, olaparib, to induce RAD51 foci formation, suggesting that THZ531 specifically causes a defect in homologous recombination repair. Moreover, we observed striking synergy of THZ1 and olaparib in two mouse models of Ewing sarcoma with limited toxicity observed. These findings have important translational significance as clinical trials with PARP inhibitors as single agents in Ewing sarcoma failed to demonstrate efficacy, highlighting the need to identify combination therapies that will enhance the activity of PARP inhibition. We anticipate that CDK12 and PARP inhibitor combinations will be of therapeutic interest in other ETS-rearranged tumors, as well as tumors with defects in DNA repair.

Citation Format: Amanda L. Balboni, Bjorn Stolte, Amy Saur Conway, Gabriela Alexe, Emily Jue Wang, Nicholas Kwiatkowski, Tinghu Zhang, Brian J. Abraham, Peter Kalev, Dipanjan Chowdhury, Cyril H. Benes, Richard A. Young, Nathanael S. Gray, Kimberly Stegmaier. Synthetic lethality of CDK12 inhibition in tumors with EWS/FLI rearrangements [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 1118. doi:10.1158/1538-7445.AM2017-1118
Abstract 1125A: β-hydroxybutyrate inhibits histone deacetylase activity and radiosensitizes malignant glioma cells
Authors: Woolf Eric C. , Rossi Alex P. , Silva-Nichols Helena B. , Gardner Kara D. , Syed Nelofer , Scheck Adrienne C.
Published: July 2017

Several preclinical studies support the use of the therapeutic ketogenic diet (KD) and/or caloric restriction (CR) as an adjuvant to cancer therapy. This data not only suggests that this approach alters multiple hallmarks of cancer growth, but that it may also enhance other therapeutic modalities. We have demonstrated that the unrestricted KD greatly increases survival in a mouse model of malignant glioma when administered in combination with radiation, yet the underlying mechanisms are not fully elucidated. Mounting evidence suggests that the abnormal epigenetic landscape in tumors may, among other things, impact radiosensitivity. Specifically, many cancers exhibit increased histone deacetylase (HDAC) activity which contributes to the epigenetic milieu found in tumors and alters DNA damage repair. It was recently demonstrated that the ketone body β-hydroxybutyrate (BHB) inhibits HDAC activity in normal mouse tissue. As the use of HDAC inhibitors as anti-cancer agents has generated great interest, we examined the effect of BHB on HDAC activity and radiosensitivity in the context of malignant glioma. We found that BHB radiosensitizes mouse glioma, human glioma and human glioma stem-like cells in vitro. We also demonstrate that BHB inhibits HDAC activity in a dose dependent manner and alters key components of DNA damage repair. Taken together this data opens up another avenue for understanding the mechanisms underlying the KD and its impact on radiation therapy, ultimately helping us better understand how to implement it for clinical use in oncology.

Citation Format: Eric C. Woolf, Alex P. Rossi, Helena B. Silva-Nichols, Kara D. Gardner, Nelofer Syed, Adrienne C. Scheck. β-hydroxybutyrate inhibits histone deacetylase activity and radiosensitizes malignant glioma 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 1125A. doi:10.1158/1538-7445.AM2017-1125A
Abstract 1126: Potent inhibition of HCMV by modulating the cellular SNARE syntaxin 5
Authors: Desai Dhimant H. , Cruz Linda , Streck Nicholas T. , Desai Trisha D. , Lukacher Aron , Amin Shantu G. , Buchkovich Nicholas J.
Published: July 2017

Human cytomegalovirus (HCMV), also referred to as human herpesvirus-5 (HHV-5), can cause serious and even fatal disease in immunocompromised individuals and newborns, namely individuals with AIDS, solid organ transplant recipients, chemotherapy patients and recipients of bone marrow and stem cell transplants. HCMV is a ubiquitous virus found throughout all geographic regions and socioeconomic groups, infecting greater than 50% of adults in industrialized countries and as many as 100% in developing countries. Although current therapeutics improves clinical outcomes, they are limited by toxicity, intravenous infusion and the development of resistance by the virus. Thus, there is a pressing need to develop novel therapeutics to prevent HCMV infections with concomitant organ toxicity. Formation of the cytoplasmic viral assembly compartment (cVAC) is an important step for efficient HCMV assembly. To do this, the virus must alter and repurpose the normal cellular balance of membrane and protein flux, a process that is not well understood. We have identified a compound Retro94, which potently inhibits production of infectious HCMV virions in cells by operating against a host cell process, rather than directly targeting the virus. The presence of Retro94 results in the severely impaired production of infectious virions, as great as 5 logs (99-99.99%). Here we discuss in vitro, in vivo, stability, and binding study of Retro94. Overall, our findings have identified Retro94, as novel agent that affects key cellular trafficking factors important for supporting HCMV infection.

Citation Format: Dhimant H. Desai, Linda Cruz, Nicholas T. Streck, Trisha D. Desai, Aron Lukacher, Shantu G. Amin, Nicholas J. Buchkovich. Potent inhibition of HCMV by modulating the cellular SNARE syntaxin 5 [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 1126. doi:10.1158/1538-7445.AM2017-1126
Abstract 1131: O-GlcNAc transferase inhibition in breast cancer cells
Authors: Barkovskaya Anna , Prasmickaite Lina , Duveau Damien Y. , Mills Ian G. , Mælandsmo Gunhild M. , Moestue Siver A. , Itkonen Harri M.
Published: July 2017

O-linked-N-acetylglucosamination (O-GlcNAcylation) is a post-translational modification that occurs on serine and threonine amino acid residues of the intracellular proteins. O-GlcNAcylation of numerous targets is catalyzed by a single enzyme - O-GlcNAc-transferase (OGT). O-GlcNAcylation impacts protein activation and stability thereby regulating several key biological functions, and is heavily involved in cancer development and progression. OGT expression and total protein O-GlcNAcylation are elevated in many cancers compared to non-malignant adjacent tissues. In breast cancer, this increase also has a positive correlation with the tumor grade suggesting a possible link to metastasis and disease progression. Here we investigated the effects of OGT inhibition in two triple-negative (TNBC) and two receptor-positive luminal breast cancer cell lines. Treatment of cells with an OGT inhibitor as well as OGT knockdown led to a strong decrease in viability and proliferation of the TNBC cells, but significantly less so in the luminal receptor-positive cell lines. This differential response was evaluated using analysis of apoptosis, cell cycle, gene expression and a reverse-phase antibody-based protein array (RPPA). We found that cell cycle progression was affected by OGT inhibition. In addition, proteomics data pointed towards the transcription factor hairy and enhancer of split-1 (HES1) as a possible mediator of the cytotoxicity observed in the TNBC cell lines. We currently work to elucidate the molecular mechanisms of HES1 regulation by OGT and its effect on TNBC cell survival and apoptosis. In conclusion, OGT inhibition has a pronounced cytotoxic effect on the TNBC cells and may have some potential for therapeutic use in the future.

Citation Format: Anna Barkovskaya, Lina Prasmickaite, Damien Y. Duveau, Ian G. Mills, Gunhild M. Mælandsmo, Siver A. Moestue, Harri M. Itkonen. O-GlcNAc transferase inhibition in breast 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 1131. doi:10.1158/1538-7445.AM2017-1131
Abstract 1138: The protein disulfide isomerase inhibitor XCE853 inhibits in vitro, ex-vivo and in vivo growth of human tumors
Authors: Prevost Gregoire Pierre , Chauchereau Anne , Ladam Patrick , Seigneuric Renaud , Carniato Denis , Pitty Marc-Henry , Foster Paul
Published: July 2017

Protein disulfide isomerase (PDI) is a chaperone protein that regulates oxidative protein folding as well as cell viability. Increased PDI levels have been documented in a variety of human cancers associated with a poor overall survival, including ovarian, prostate, brain and lung cancers. Inhibition of PDI activity leads to apoptosis in cancer, suggesting that PDI is a promising druggable target. XCE853 is a synthetic small molecule displaying an excellent docking with the catalytic domain of the human PDI. XCE853 inhibits in vitro recombinant PDI enzymatic activity. In addition, the proliferation of a large panel of human tumor cells is blocked by XCE853 with IC50s in the nanomolar range through an irreversible cytolysis leading to a tumor cell death by autophagy and particles release (vesicles or protein aggregates). XCE853 is also active on a large panel of drug resistant human cancer cells. XCE853 induced an irreversible cytolysis of human tumor cells after a short in vitro exposure independently of efflux pumps. In addition, the ex-vivo approach using fresh human tumor explants cultivated in 3 dimensions with low concentrations of XCE853 has shown a strong decrease of the proliferation (KI-67 labeling) in several tumor types. Finally, XCE853 displayed excellent oral bioavailability in mice and was able to block the growth of several human cancers using in vivo xenograft models leading to a complete tumor growth arrest even after the cessation of the treatment. Altogether, these data strongly support further efforts to move this drug candidate to the preclinical studies to access advanced cancer patients.

Citation Format: Gregoire Pierre Prevost, Anne Chauchereau, Patrick Ladam, Renaud Seigneuric, Denis Carniato, Marc-Henry Pitty, Paul Foster. The protein disulfide isomerase inhibitor XCE853 inhibits in vitro, ex-vivo and in vivo growth of human tumors [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 1138. doi:10.1158/1538-7445.AM2017-1138
Abstract 1142: Novel target discovery for glioblastoma using chemical biology fingerprinting
Authors: Finlay Darren , Aza-Blanc Pedro , Dhruv Harshil , Eroshkin Alexey , Hauser Craig , Kiefer Jeff , Kim Seungchan , Long Tao , Oshima Robert G. , Peng Sen , Speyer Gil , Berens Michael , Vuori Kristiina
Published: July 2017

The most common adult brain tumor is Glioblastoma Multiforme (GBM), an extremely aggressive cancer with only scant treatment options. Even with standard of care most patients present with a recurrence and the median survival is only circa 15 months. The need, therefore, for new therapeutic targets and treatment options is pressing. Here we describe here a multipronged approach to identifying said targets. We present an established methodology for the isolation and culture of patient derived GBM samples that retain the “stem-like” fraction thought to underlie resistance and recurrence. Furthermore we show genomically that these samples represent specific subtypes of the disease yet still form distinct groups in unbiased clustering analysis. Thus we have multiple representative patient derived cultures that are suitable for our drug discovery and chemical biology analyses. Using a process we term Chemical Biology Fingerprinting (CBF) we utilize small focused, and clinically relevant, chemical collections in order to identify patterns of chemovulnerabilities across multiple samples. This allows an unbiased yet cancer relevant sub-stratification and the identification of agents, and therefore targets, which may be relevant for GBM patient subtypes. Indeed our use of the highly annotated NCI CTD2 Informer Set of chemicals allows ready drug-to-target mapping and facilitates data sharing across the CTD2 network. Moreover, already defined subgroups can be clustered to find agents, or groups of agents, that show selective activity against traditional classifications (e.g. proneural, mesenchymal etc.). Finally our strategy is permissive for the identification of “exceptional responders”. That is, individual patient samples that respond to a specific drug whilst most samples are refractory. In sum we demonstrate generation of patient derived models and identify specific, and novel, drugs that may be relevant for specific GBM subtypes. Supported by NIH U01CA168397

Citation Format: Darren Finlay, Pedro Aza-Blanc, Harshil Dhruv, Alexey Eroshkin, Craig Hauser, Jeff Kiefer, Seungchan Kim, Tao Long, Robert G. Oshima, Sen Peng, Gil Speyer, Michael Berens, Kristiina Vuori. Novel target discovery for glioblastoma using chemical biology fingerprinting [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 1142. doi:10.1158/1538-7445.AM2017-1142
Abstract 1145: Overcoming chemoresistance and blocking metastasis in breast cancer by targeting HuR
Authors: Wu Xiaoqing , Marquez Rebecca , Han Shuang , Lan Lan , Dixon Dan A. , Aubé Jeffrey , Welch Danny R. , Xu Liang
Published: July 2017

Patients with metastatic breast cancer have a dismal 5-year survival rate of only 24%. Chemoresistance is another contributor to the high mortality of advanced breast cancer. The RNA-binding protein, Hu antigen R (HuR), is overexpressed at all stages of breast cancer development. Cytoplasmic HuR accumulation correlates with high-grade malignancy, poor distant disease-free survival and serves as a prognostic factor for poor clinical outcome in breast cancer. HuR promotes tumorigenesis by promoting mRNA stability and translation of proteins implicated in proliferation, survival, angiogenesis, invasion, and metastasis. HuR also modulates sensitivity of breast cancer cells to chemotherapy. Taken together, HuR is an emerging target for breast cancer therapy, especially metastatic breast cancer. Using shRNA and CRISPR technologies to modulate HuR expression in breast cancer cells, we found that cells with HuR KD/KO were less invasive and more sensitive to chemotherapy. In an effort to discover small molecules that disrupt the HuR-mRNA interaction and block HuR functions in breast cancer progression, metastasis and chemoresistance, high throughput screening (HTS) was carried out in several chemical libraries (~23,000 compounds) using fluorescence polarization (FP) assay, which identified several initial hits with sub-micromolar inhibitory constants (Ki). Those potential inhbitors were then validated by ALPHA assay (Amplified Luminescent Proximity Homogeneous Assay), confirmed by Surface Plasmon Resonance (SPR). In cell-based assays, top hit KH-3 and its optimized analogs, specifically shortened HuR target mRNA half-lifes and decreased the level of the encoded proteins. Moreover, those compounds inhibited invasion and restored chemosensitivity. qPCR arrays focusing on specific pathways revealed that HuR inhibitors potently upregulated metastatic suppressors and downregulated genes frequently overexpressed in lung metastases. In animal studies, KH-3 not only exhibited potent antitumor efficacy in orthotopic xenografts of breast cancer, but also efficiently blocked experimental metastasis. In conclusion, we identified potent and specific small molecule inhibitors of HuR-mRNA interaction for potential anti-metastatic therapy for breast cancer with HuR overexpression.

Citation Format: Xiaoqing Wu, Rebecca Marquez, Shuang Han, Lan Lan, Dan A. Dixon, Jeffrey Aubé, Danny R. Welch, Liang Xu. Overcoming chemoresistance and blocking metastasis in breast cancer by targeting HuR [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 1145. doi:10.1158/1538-7445.AM2017-1145
Abstract 1164: A novel hypoxia-inducible factor-1 inhibitor IDF-11774 regulates cancer metabolism, thereby suppressing tumor growth
Authors: Won Misun , Ban Hyun Seung , Lee Kyeong , Lee Hongsub , Kim Bo-Kyung , Kim Hwan Mook , Naik Ravi , Park Song-Kyu , Park Joon-Tae , Kim Inhyub , Nam Miso , Hwang Geum-Sook
Published: July 2017

HIF-1 is associated with poor patient prognosis and therapeutic resistance of cancer. We have developed a novel hypoxia-inducible factor (HIF)-1 inhibitor, IDF-11774, as a clinical candidate for cancer therapy. Under hypoxic condition, IDF-11774 inhibited the accumulation of HIF-1α in vitro and in vivo in colorectal carcinoma HCT116 cells. IDF-11774 suppressed the angiogenesis of cancer cells by reducing the expression of HIF-1 target genes. Moreover, IDF-11774 reduced glucose uptake, leading sensitizing cell growth on low glucose condition. IDF-11774 also decreased the extracellular acidification rate (ECAR) and oxygen consumption rate (OCR). Metabolic profile of IDF-11774-treated cells revealed low levels of NAD+, lactate, and intermediates in glycolysis and tricarboxylic acid (TCA) cycle. More importantly, we observed elevated AMP and diminished ATP level, leading high AMP/ATP ratio. Apparently, phosphorylation of AMPK increased, leading inhibition of mTOR signaling in cells. In vivo xenograft assays demonstrated that IDF11774 has significant anti-cancer efficacy by targeting cancer metabolism in mouse models containing the KRAS, PTEN or VHL mutation, which often occurs in many malignant cancers. Collectively, IDF-11774 suppresses the hypoxia-induced HIF-1α accumulation, thereby repressing tumor growth by regulating cancer metabolism.

Citation Format: Misun Won, Hyun Seung Ban, Kyeong Lee, Hongsub Lee, Bo-Kyung Kim, Hwan Mook Kim, Ravi Naik, Song-Kyu Park, Joon-Tae Park, Inhyub Kim, Miso Nam, Geum-Sook Hwang. A novel hypoxia-inducible factor-1 inhibitor IDF-11774 regulates cancer metabolism, thereby suppressing tumor growth [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 1164. doi:10.1158/1538-7445.AM2017-1164
Abstract 1184: Characterization of novel STAT5 inhibitors to interfere with the oncogenic activities of STAT5 in hematopoietic diseases
Authors: Wingelhofer Bettina , Maurer Barbara , Heyes Elizabeth C. , Freund Patricia , Cumaraswamy Abbarna A. , Park Jisung , Kubicek Stefan , Valent Peter , Gunning Patrick T. , Moriggl Richard
Published: July 2017

Activation of the transcription factor STAT5 is essential for the pathogenesis of acute myeloid leukemia (AML) containing the FLT3 internal tandem duplication (ITD). FLT3 ITD is a constitutively active tyrosine kinase (TK) that drives the activation of STAT5 leading to the growth and survival of AML cells. Although there has been some success in identifying TK inhibitors that block the function of FLT3 ITD, treatment options are still limited. This is mainly due to drug resistance development by mutations that allow for the continued activation of STATs. Since STAT5 represents a critical mediator of malignant cellular behavior and sits at the convergence point of many kinase pathways, the direct targeting of STAT5 may be an effective means of overcoming this resistance to TK inhibitors. First, we screened a library of potential STAT5 inhibitors for specific SH2 domain binders using a fluorescent polarization assay. Thereby, we identified small inhibitory molecules, called AC-3-019 and AC-4-130, that bind to the SH2 domain of STAT5, subsequently resulting in the disruption of the reciprocal STAT5-phosphopeptide interactions. They efficiently blocked kinase-mediated phosphorylation, dimer formation, nuclear translocation, DNA binding and STAT5 mediated target gene expression. Further, we observed a time- and dose-dependent impairment of proliferation, blocked cell cycle progression and increased apoptosis. Studies with human AML patient-derived samples similarly showed an induction of apoptotic cell death and decreased colony forming capabilities. A combinatorial drug screen revealed synergistic effects with TK inhibitors, as well as with drugs standardly used in the treatment of AML patients, e.g. Cytarabine. Finally, AC-3-019 and AC-4-130 significantly suppressed tumor growth in vivo without general toxicity in healthy organs. Overall, our findings indicate that AC-3-019 and AC-4-130 are potent and selective inhibitors of STAT5. These compounds provide lead structures for further chemical modifications and clinical development for the identification of compounds to improve existing therapies.

Citation Format: Bettina Wingelhofer, Barbara Maurer, Elizabeth C. Heyes, Patricia Freund, Abbarna A. Cumaraswamy, Jisung Park, Stefan Kubicek, Peter Valent, Patrick T. Gunning, Richard Moriggl. Characterization of novel STAT5 inhibitors to interfere with the oncogenic activities of STAT5 in hematopoietic diseases [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 1184. doi:10.1158/1538-7445.AM2017-1184
Abstract 1187: Synthetic lethality screening reveals ATR as responsible for oxaliplatin resistance in colorectal cancer cells
Authors: Combes Eve , Faria-Andrade Augusto , Tosi Diego , Martineau Pierre , Rio Maguy Del , Beijersbergen Roderick , Vie Nadia , Gongora Céline
Published: July 2017

Despite the recent advances achieved in the treatment of colon cancer, tumor resistance is a frequent cause of chemotherapy failure. Our work was aimed to determine the molecular mechanisms involved in the resistance to oxaliplatin, an anticancer agent widely used in colorectal cancer treatment. To this end, we establish an oxaliplatin-resistant cellular model from the colon adenocarcinoma cell line HCT-116. Among cellular clones obtained, we used one displaying mild resistance (10 fold called HCT116-R1) to perform short hairpin RNA-based loss of function genetic screen in order to identify genes that can modulate the cellular response to oxaliplatin by revealing genes the silencing of which causes drug sensitivity (synthetic lethal interactions with the drug). Using this screen, we have identified ATR (Ataxia-telangiectasia mutated and rad3 related), a protein that plays a key role in the repair of DNA double-strand breaks induced by various DNA damaging agents, including platinum derivatives. We further validated ATR implication in oxaliplatin resistance by showing that (i) shRNA-mediated repression of ATR in HCT116-R1 oxaliplatin-resistant CRC cells sensitizes such cells to the drug; (ii) co-incubation with the ATR inhibitor VE-822 (or VX-970) and oxaliplatin led to a dramatic synergistic effect in six different CRC cell lines (two oxaliplatin-sensitives: HCT116 and SW48; and four oxaliplatin-resistant: HCT116-R1, HCT116-R2, SW48-R1 and SW48-R2) using 2D and 3D cell growth inhibition assays and in vivo. The synergistic effect was evaluated using dose matrix data (an algorithm that was implemented in our group); (iii) the synergistic effect of oxaliplatin and VE-822 was accompanied by an increase of ssDNA, DNA double-strand breaks, growth arrest and apoptosis induction. In conclusion, our preliminary data confirm the results of our screen by demonstrating for the first time the functional role of ATR in the sensitivity to oxaliplatin.

Citation Format: Eve Combes, Augusto Faria-Andrade, Diego Tosi, Pierre Martineau, Maguy Del Rio, Roderick Beijersbergen, Nadia Vie, Céline Gongora. Synthetic lethality screening reveals ATR as responsible for oxaliplatin resistance in colorectal 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 1187. doi:10.1158/1538-7445.AM2017-1187
Abstract 1191: The dopamine (DA) D3 receptor antagonists (PG01037, NGB2904, SB-277011A, and U99194) significantly attenuate ABCG2-mediated multidrug resistance
Authors: Hussein Noor , Amawi Haneen , Ashby Charles R. , Chandrabose Karthikeyan , Mittal Roopali , Christman Ryann , Trivedi Piyush , Tiwari Amit
Published: July 2017

ATP-binding family G2 (ABCG2) transporters are known to produce multidrug resistance (MDR) and limit successful cancer chemotherapy. Using molecular modeling, we obtained data indicating that highly potent and selective dopamine (DA) D3 receptor antagonists had significant docking scores for the active site of the ABCG2 transporter. In this in vitro study, we determined the effect of the D3 receptor antagonists (PG01037, NGB2904, SB-277011A, and U99194) on MDR resulting from the overexpression of ABCG2 transporters. The D3 receptor antagonists alone did not significantly affect the viability of HEK293/ABCG2, H460/MX-20, S1-M1-80 or A549-MX-10 cells, which overexpress ABCG2 transporters. However, the D3 receptor antagonists (PG01037, NGB2904, SB-277011A, and U99194) significantly increased the efficacy of the anticancer drugs mitoxantrone and doxorubicin in the above mentioned cell lines. Efflux studies indicated that both PG01037 and NGB2904 significantly decreased the efflux of rhodamine 123 from H460-MX20 cells. Interestingly, PG01037 and NGB2904 significantly decreased the expression levels of the ABCG2 protein levels as shown by immunocytochemical and Western blot analysis. This suggests that D3 antagonists inhibit both function and expression of ABCG2 transporters at relevant non-toxic concentrations. In conclusion, our in vitro results indicate that PG01037, NGB2904, SB-277011A, and U99194 reverse resistance to mitoxantrone and doxorubicin mediated by overexpression of ABCG2 transporters. Further mechanistic and animal studies are warranted to establish the clinical use of D3 receptor antagonists in reversing ABCG2-mediated MDR.

Citation Format: Noor Hussein, Haneen Amawi, Charles R. Ashby, Karthikeyan Chandrabose, Roopali Mittal, Ryann Christman, Piyush Trivedi, Amit Tiwari. The dopamine (DA) D3 receptor antagonists (PG01037, NGB2904, SB-277011A, and U99194) significantly attenuate ABCG2-mediated multidrug resistance [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 1191. doi:10.1158/1538-7445.AM2017-1191
Abstract 1202: Targeting PIK3C3 to overcome drug resistance resulted from prosurvival autophagy in cancer cells
Authors: CHEN CHUN-HAN
Published: July 2017

Autophagy is an important cellular recycling mechanism in which portions of cytosol or organelles are sequestered into a double-membrane structure and delivered to lysosome for degradation. PIK3C3 is the only class III PI3K, which specifically generates phosphatidylinositol 3-phosphate (PtdIns3P). It in turn recruits proteins containing FYVE or PX domains, thereby initiating various complexes at the membranes of endosomes, phagosomes and autophagosomes. Recently, several studies have shown that autophagy is upregulated in cancer cells when exposing to chemotherapy and radiotherapy. Therefore, the rationale of targeting autophagy addiction in cancer was proposed by combining autophagy inhibition with agents that induce autophagy as a pro-survival response to increase their therapeutic efficacy. We stably knocked down PIK3C3 in cancer cell lines and combined with clinical therapeutic agents reportedly induce pro-survival autophagy. Cell viability was examined by MTT assay and combination index was determined by Compusyn software. The autophagy flux was evaluated by detecting protein levels of LC-3II and p62 through western blot analysis. The results showed PIK3C3 knockdown synergistically sensitize the killing effects of gefitinib and gemcitabine in A549 cells and Panc1 cells, respectively. Both of gefitinib and gemcitabine increased autophagy flux, as evidence by the increase of LC3-II and decrease of autophagy substrate, p62. However, the combination of PIK3C3 knockdown and therapeutic agents increased both of the protein levels of LC3-II and p62. These data suggest incomplete autophagy when the function of PIK3C3 was inhibited. The phenomenon was confirmed by bombing autophagy inducer and PIK3C3 inhibitors. Moreover, no appreciable apoptotic cell death was observed. Taken together, our study revealed a potential strategy by targeting PIK3C3 to overcome drug resistance associated with the pro-survival autophagy in cancer.

Citation Format: CHUN-HAN CHEN. Targeting PIK3C3 to overcome drug resistance resulted from prosurvival autophagy in 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 1202. doi:10.1158/1538-7445.AM2017-1202