bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1862: CX5461 in combination with radiotherapy I effective against gynecological tumors
Authors: Ismael Mohammed , Webb Roger , Ajaz Mazhur , Coley Helen
Published: August 2018

An increased rate of cellular proliferation is a hallmark of cancer and may be accompanied by increase in ribosome biogenesis and dysregulation in rRNA synthesis. In this regard CX-5461 has been developed as a novel RNA POL1 inhibitor and is currently in Phase I/II clinical trials. We have set out to explore the use of this agent in combination with radiation therapy and to understand the associated molecular mechanisms using this approach. A panel of human tumour cell lines treated with CX-5461 indicated a broad spectrum of sensitivity (MTT assay) with IC50 values varying from 25nM - >2µM. No clear relationship between p53 status and sensitivity to CX-5461 was indicated and the mode of cell death was cell context dependent - either via autophagy (LC3I→ LC3II conversion, with P62 sequestosome decrease), sometimes via apoptosis (annexinV staining, caspase-3 activation), also in the presence of increased senescence (β-galactosidase activity). Combination treatment experiments involving CX-5461 alongside radiation therapy (0-16Gy) showed marked synergistic effects for some cancer cell lines, particularly the cervical cancer CASKI line (HPV16+ve). Highly significant effects were seen when low dose radiation and low dose CX-5461 were used together in CASKI cells: combination index CI=< 0.2 with 6nM CX-5461 and 2Gy (isobologram analysis). Cell cycle analysis of CASKI cells treated in combination indicated cell cycle disruption with prolonged S-phase, giving some insight into some of the associated mechanisms involved. In addition, we have found that BRCA-mutant PEO1 ovarian cancer cells were sensitive to CX-5461, IC50 approx. 100nM, whereas carboplatin-resistant PEO1CarbR (with reversed BRCA mutant status) cells gave an IC50 value >3µM In addition, proteomic studies have shown that PEO1CarbR cells overexpress a number of nucleolar proteins and we are investigating the relevance of this in relation to CX-5461 sensitivity. Our further studies aim to identify potential biomarkers of response to CX-5461 and may also inform the design of clinical trials of this novel agent.

Citation Format: Mohammed Ismael, Roger Webb, Mazhur Ajaz, Helen Coley. CX5461 in combination with radiotherapy I effective against gynecological tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1862.
Abstract 1869: Role of Nef secretion modification region (SMR) peptides and the chaperone mortalin in breast cancer and leukemia cells
Authors: Huang Ming B. , Bond Vinvent C.
Published: August 2018

BACKGROUND: Mortalin/GRP-75(mt-hsp70, HSPA9) is a mitochondrial chaperone protein, also

found in the cytoplasm, endoplasmic reticulum and cytoplasmic vesicles. It functions in many

cellular processes such as mitochondrial biogenesis, intracellular trafficking, cell proliferation,

signaling, immortalization and tumorigenesis, Thus, inhibition of mortalin is a promising avenue

for cancer therapy. Previous studies in our lab have suggested that mortalin contributes to breast

cancer development and progression. We showed tumor exosome secretion was decreased by

knockdown of mortalin expression using HIV-1 Nef peptides. Specifically, these peptides can

block exosome secretion and also mediate cell cycle arrest in MDA-MB-231 and MCF-7 breast

cancer cells.

AIMS: This study aims to investigate further the function and mechanism of interaction of PEG-

SMR-CLU peptide and SMR-CPP peptide, and chaperone mortalin and to explore the effect of

SMR-derived peptides and mortalin on human breast cancer and leukemia cell lines.

RESULTS: Our results demonstrate that the modified SMRwt peptides not only affect breast

cancer cell proliferation and arrest breast cancer cell growth, but they also inhibit migration of

breast cancer cells. SMRwt peptides also block exosome-mediated release of complement, and

allow the cells to die via complement induced cell death, and reduced mortalin protein expression.

We further determined that expression levels of the mesenchymal markers vimentin (VIM) was

decreased in presence of SMRwt peptides and MKT-077.

CONCLUSIONS: Mortalin may promote cell proliferation and invasion via induction of epithelial

mesenchymal transition (EMT) of cancer cells, which has a potential therapeutic target in cancer

immunotherapy. SMRwt peptides block tumor exosome release and reduce the expression of

mortalin. This may be a means to decreases breast cancer cell invasion and metastasis, which

may have important clinical applications for late stage breast cancer chemotherapy. Furthermore,

SMRwt peptides and inhibition of mortalin suppressed the migration and invasive capacity of

cancer cells and is associated with a diminished EMT. These findings support a role for SMR

peptide and mortalin in the induction of EMT, prompting a further investigation into their

therapeutic value in cancer metastasis.

Citation Format: Ming B. Huang, Vinvent C. Bond. Role of Nef secretion modification region (SMR) peptides and the chaperone mortalin in breast cancer and leukemia cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1869.
Abstract 1878: Molecular mechanisms of the cardiotoxicity of the proteasomal-targeted anticancer drugs bortezomib, carfilzomib, ixazomib, oprozomib, and delanzomib
Authors: Hasinoff Brian B.
Published: August 2018

Bortezomib, carfilzomib, ixazomib, oprozomib, and delanzomib are anticancer drugs that target the proteasomal system. Bortezomib, carfilzomib, and ixazomib, which are approved for clinical use, have shown some cardiotoxicity. Carfilzomib and oprozomib are epoxyketones that form an irreversible bond with the 20S proteasome, whereas bortezomib, ixazomib, and delanzomib are boronic acids that form slowly reversible adducts. A primary neonatal rat myocyte model was used to study these cardiotoxic mechanisms. Using LDH release as a measure of damage in the myocyte model, after drug treatments of either 1, 4 and 72 hr all these drugs induced myocyte damage at low- to sub-micromolar concentrations. Oprozomib induced significantly less myocyte damage than any of the other drugs. Utilizing a fluorogenic substrate the kinetics of the slow-binding inhibition of the chymotrypsin-like proteasomal activity of human 20S proteasome were also determined in order to see if differences in the binding kinetics could explain the degree of myocyte damage. Oprozomib inhibited the 20S proteasome with a second-order binding “on” rate constant that was 60-fold slower than for ixazomib, the fastest binding drug. The first-order dissociation “off” rate constants for the three boronic acids were also determined. Delanzomib dissociated from its complex with the 20S proteasome with a half-time that was more than 20-fold slower than for ixazomib, the fastest dissociating drug. In conclusion, while all these drugs were potently toxic to myocytes at submicromolar concentrations, oprozomib was considerably less toxic than any of the other drugs. As a group the boronic acid drugs were not significantly more toxic than the epoxyketone drugs. The dissociation half-times of the boronic acid complexes were also not correlated with myocyte damage. The fact that oprozomib bound to the 20S proteasome more slowly than any of the other drugs may be the reason, in part, that it is less toxic. Support: CIHR; a Canada Research Chair in Drug Development.

Citation Format: Brian B. Hasinoff. Molecular mechanisms of the cardiotoxicity of the proteasomal-targeted anticancer drugs bortezomib, carfilzomib, ixazomib, oprozomib, and delanzomib [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1878.
Abstract 1893: The evaluation of INCB059872, an FAD-directed inhibitor of LSD1, in preclinical models of T-ALL
Authors: Diamond Melody , Lo Yvonne , Chadderton Antony , Ye Min , Roman Valerie , Weber Michael , He Chunhong , Wu Liangxing , Yeleswaram Swamy , Roberts Alan , Yao Wenqing , Hollis Gregory , Huber Reid , Scherle Peggy , Ruggeri Bruce , Lee Sang Hyun
Published: August 2018

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological tumor that is derived from the clonal expansion of immature T-cell progenitors. Multiple genetic and epigenetic alterations are attributed to the development of malignant T cell transformation. Among these, there is supporting evidence for a role of lysine specific demethylase (LSD1) in T-ALL. Oncogenic transcription factors, such as TAL-1, Notch, and ZEB2, form a complex with LSD1 to alter gene expression in T-ALL cells. In addition, LSD1 is aberrantly expressed in ALL, including B-ALL and T-ALL. Furthermore, the overexpression of LSD1 under control of the Sca-1 promoter in transgenic mice triggered T leukemogenesis via acquisition of self-renewal activity and alteration in the differentiation program to T-cell lineages. Together with the known function of LSD1 in regulating the activity of self-renewal in hematological malignancies, these studies prompted evaluation of the efficacy of the potent, selective, and orally bioavailable FAD-directed LSD1 inhibitor, INCB059872, in preclinical models of T-ALL. Expression of LSD1 was abundant in human-T-ALL cell lines as detected by immunoblotting. In vitro, INCB059872 treatment significantly inhibited the proliferation of a subset of human T-ALL cell lines. In vivo, once daily oral administration of INCB059872 inhibited tumor growth significantly in multiple human T-ALL subcutaneous xenograft models including Molt-4, RPMI-8402, CCRF-HSB-2, and CCRF-CEM, but was ineffective against DND-41 xenografts. The anti-tumor efficacy observed with INCB059872 had no clear genetic correlation with Notch mutation status of T-ALL tumors. Combination efficacy studies of INCB059872 with standard care of agents or targeted therapeutic agents in T-ALL models are currently being evaluated. These data suggest exploring the potential clinical development of INCB059872 as a therapy for T-ALL patients.

Citation Format: Melody Diamond, Yvonne Lo, Antony Chadderton, Min Ye, Valerie Roman, Michael Weber, Chunhong He, Liangxing Wu, Swamy Yeleswaram, Alan Roberts, Wenqing Yao, Gregory Hollis, Reid Huber, Peggy Scherle, Bruce Ruggeri, Sang Hyun Lee. The evaluation of INCB059872, an FAD-directed inhibitor of LSD1, in preclinical models of T-ALL [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1893.
Abstract 1899: Targeting interferon induced transmembrane protein-1 (IFITM1) attenuates the aggressive phenotype of inflammatory breast cancer
Authors: Provance Olivia , Geanes Eric , Ogony Joshua , Lui Asona , Young Eric , Gunewardena Sumedha , Lewis-Wambi Joan
Published: August 2018

Inflammatory breast cancer (IBC) is the most aggressive and lethal subtype of breast cancer, with triple-negative IBC being the most difficult to treat IBC subgroup. Improved understanding of mechanisms that lead to aggressiveness of triple-negative IBC could provide a basis for therapeutic targets. Our laboratory has identified a novel interferon (IFN)-α signaling target called interferon induced transmembrane protein-1 (IFITM1), which we hypothesize to promote the aggressive phenotype of triple-negative IBC. CRISPR/CAS9 was utilized to silence IFITM1 in SUM149 TN-IBC cells. In vitro, we found that knockout of IFITM1 increased in colony and mammosphere formation, inhibited migration as observed by the wound healing assay, and enhanced sensitivity to mainstay chemotherapeutic agents (taxol and doxorubicin) analyzed by flow cytometry, MTT and Tunel staining. Western blot analysis shows a decrease in c-Src and p-Src, vimentin, and CD44v expression, which are important regulators of migration and invasion. RNA sequencing analysis further indicates that knocking down IFITM1 promotes overall downregulation of pathways including breast cancer invasion, supporting our in vitro findings. In vivo, IFITM1-CRISPR/KD SUM149 cells were injected into the mammary fat pads of immunosuppressed female NSG mice to assess tumor growth. We found that mice injected with IFITM1-CRISPR/KD SUM149 cells showed significantly reduced tumor growth compared to mice injected with CRISPR/control SUM149 cells, which was observed at all time points examined. We used the mammary intraductal (MIND) method to assess tumor invasion in vivo. IFITM1-CRISPR/KD SUM149 cells showed decreased invasion outside of the mammary duct and decreased vimentin expression, further corroborating our in vitro data. Lastly, through tail vein injections to model metastasis, 33% of mice injected with SUM149 wildtype cells developed liver metastasis while 0% of mice injected with IFITM1-CRISPR/KD SUM149 mice developed liver metastasis. We have ongoing studies to further understand the mechanism by which IFITM1 regulates cellular migration, as well as invasion and angiogenesis in triple-negative IBC, which are all shown to be downregulated through RNA sequencing analysis. Overall, these findings indicate that IFITM1 may be driving the aggressiveness of triple-negative IBC and they suggest that IFITM1 may serve as a potential therapeutic target.

Citation Format: Olivia Provance, Eric Geanes, Joshua Ogony, Asona Lui, Eric Young, Sumedha Gunewardena, Joan Lewis-Wambi. Targeting interferon induced transmembrane protein-1 (IFITM1) attenuates the aggressive phenotype of inflammatory breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1899.
Abstract 1900: Disruption of EGFR and integrin b1 signaling in triple-negative breast cancer through targeting SHC1
Authors: Chang Ya-Fang , Cordell Elizabeth , Wang Yuhao , Greene Geoffrey
Published: August 2018

Triple-negative breast cancer (TNBC) accounts for 15-20% of breast cancer cases and is more prevalent among young women and African American women. SHC1 (Src Homology 2 Domain Containing Transforming Protein 1) is an adaptor protein that can transmit cell surface receptor signaling and activate the Ras-ERK pathway. SHC1 is found to be overexpressed in breast cancers and is important in the regulation of tumor progression and drug resistance in ER+ breast cancer. Elevated SHC1 correlates with poor prognosis in breast cancer patients. However, the biological significance of SHC1 in TNBC is not known. In this study, we performed siRNA-mediated knockdown to determine the importance of SHC1 in cell proliferation and drug response in TNBC. We found that although siSHC1 slightly inhibited the tumor growth of TNBC cells, siSHC1 + paclitaxel significantly decreased cell proliferation and increased caspase-3/7 activity in vitro. In invasion assays, siSHC1 significantly decreased the invasion of TNBC cells. To better understand the systemic regulation by SHC1, proteomic analysis was performed after siSHC1 or Scr transfection. Pathway analysis revealed the involvement of PI3K/AKT, FAK, and actin cytoskeleton pathways, by disruption of EGFR and integrin β1 signaling, in the control of TNBC progression and drug sensitivity. In tumor explant studies, siSHC1 significantly enhanced paclitaxel-induced tumor shrinkage and reduced lung metastasis. Our data suggest that SHC1 is a potential therapeutic target in TNBC.

Citation Format: Ya-Fang Chang, Elizabeth Cordell, Yuhao Wang, Geoffrey Greene. Disruption of EGFR and integrin b1 signaling in triple-negative breast cancer through targeting SHC1 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1900.
Abstract 1918: Patient-derived hormone-naive prostate cancer xenograft models reveal GRB10 as an AR-repressed gene driving the development of castration-resistant prostate cancer
Authors: Hao Jun , Ci Xinpei , Xue Hui , Wu Rebecca , Dong Xin , Zhang Fang , Qu Sifeng , Zhang Fan , Haegert Anne M. , Gout Peter W. , Collins Colin , Gleave Martin E. , Lin Dong , Wang Yuzhuo
Published: August 2018

Prostate cancer is the most commonly diagnosed noncutaneous cancer and the leading cause of cancer-related death in North American men. Although androgen-deprivation therapy is initially effective in controlling the growth of hormone-naive prostate cancers (HNPC) in patients, currently incurable castration-resistant prostate cancer (CRPC) inevitably develops. Thus, we aim to identify CRPC driver genes that may provide new targets to enhance CRPC therapy. In this study, patient-derived xenografts (PDXs) of HNPCs that develop CRPC following host castration were examined for changes in expression of genes at various time points after castration using transcriptome profiling analysis; particular attention was given to pre-CRPC changes in expression indicative of genes acting as potential CRPC drivers. Eighty genes were found to be significantly upregulated at the CRPC stage while 7 of them also showed elevated expression prior to CRPC development. Among the latter, Growth Factor Receptor Bound Protein 10 (GRB10) was the most significantly and consistently upregulated gene. Moreover, we found GRB10 expression was elevated in clinical CRPC compared to HNPC in several clinical cohorts. Further investigation suggests that GRB10 is transcriptionally regulated by androgen receptor through an androgen-responsive element located in GRB10's intron. Functionally, we found that GRB10 knockdown markedly reduced prostate cancer cell proliferation and activity of AKT, a well-established CRPC mediator. Also, a positive correlation between AKT activity and GRB10 expression was found in clinical cohorts. In conclusion, GRB10 acts as a driver of CRPC and sensitizes AR pathway inhibitors, and hence GRB10-targeting provides a novel therapeutic strategy for the disease.

Citation Format: Jun Hao, Xinpei Ci, Hui Xue, Rebecca Wu, Xin Dong, Fang Zhang, Sifeng Qu, Fan Zhang, Anne M. Haegert, Peter W. Gout, Colin Collins, Martin E. Gleave, Dong Lin, Yuzhuo Wang. Patient-derived hormone-naive prostate cancer xenograft models reveal GRB10 as an AR-repressed gene driving the development of castration-resistant prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1918.
Abstract 192: Preclinical evaluation of TQBWX220, a small-molecule inhibitor of IDO1
Authors: Liu Shilan , Liang Guibai , Wang Dahai , Chen Shuhui , Qian wenyuan , Chan Chi-Chung , Zhang Xiquan , Yang Lin , Tian Xin , Gao Yong , Dong Tiantian , Liu Mei , He Lihua
Published: August 2018

Objective: Indoleamine-2, 3-dioxygenase-1 (IDO1) catalyzes conversion of tryptophan to kynurenine (Kyn), which triggers signaling through GCN2, mTOR and AHR and affects differentiation and proliferation of T cells. Expression of IDO1 by tumor cells or host APCs can inhibit tumor-specific effector CD8+ T cells and enhance the immunosuppressing activity of regulatory T cells. Targeting the IDO pathway via inhibition of IDO1 or blocking its downstream signaling pathways is recognized as one of the prime immunomodulation approaches to unleash antitumor immunity in the tumor microenvironment. As reported, inhibition of IDO1 pathway may also synergize with inhibitory Abs of immune checkpoint proteins, PD-1 and CTLA-4, etc. We report herein TQBWX220, a potent small-molecule inhibitor of IDO.

Method: Potency of TQBWX220 was determined by corresponding IDO1 biochemical and cell assays. Antitumor efficacy of TQBWX220 was evaluated in the syngeneic CT26 xenograft colon cancer model. CT26 cells were engrafted onto the back of BALB/c mice. BID oral administration of vehicle, positive control (INCB024360, 100 mg/kg) and TQBWX220 at different doses were performed. Tumor volumes and mouse body weight were measured at time points after the start of the treatments. Other assays were carried out by using standard methods.

Result: TQBWX220 displayed good IDO1 enzymatic (IDO1 IC50=22 nM) and cellular (Hela EC50=117 nM) potency. It has excellent solubility (>500uM pH7.4) and low inhibition on CYPs and hERG. TQBWX220 significantly inhibited tumor growth at tested doses (60% TGI at 50 mpk/PO BID and 73% TGI at 100 mpk /PO BID) (P<0.05) in the CT-26 syngeneic model. As a result of IDO1 inhibition, reduction of Kyn level in the tumor was also observed.

Conclusion: The promising preclinical antitumor results and its favorable DMPK properties indicate that TQBWX220 has high potential in the clinic as a cancer immunotherapy in combination with checkpoint inhibitors such as anti-PD1 antibodies.

Citation Format: Shilan Liu, Guibai Liang, Dahai Wang, Shuhui Chen, wenyuan Qian, Chi-Chung Chan, Xiquan Zhang, Lin Yang, Xin Tian, Yong Gao, Tiantian Dong, Mei Liu, Lihua He. Preclinical evaluation of TQBWX220, a small-molecule inhibitor of IDO1 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 192.
Abstract 1924: Role of CXCL16 and ADAM10 in ovarian cancer pathogenesis
Authors: Mir Hina , Kapur Neeraj , Lillard James W. , Singh Shailesh
Published: August 2018

Ovarian cancer is the leading cause of death from gynecological malignancies. The five-year survival rate of ovarian cancer ranges from 30 to 92%, depending on the severity of the disease. Our laboratory has shown the role of chemokines and chemokines receptors in cancer, including ovarian cancer. In this study, we have shown higher expression of CXCR6, which is the only receptor of chemokine CXCL16, in ovarian cancer cell lines and clinical samples. We have tested the biological significance of CXCR6 and soluble CXCL16 (sCXCL16) using ovarian cancer cell lines in vitro. We show higher migratory and invasive potential of high CXCR6 expressing ovarian cancer cell lines in the response of sCXCL16. Migratory and invasive potential in response to sCXCL16 was significantly inhibited when CXCR6 and CXCL16 interaction was blocked using anti-CXCR6 monoclonal antibody. ADAM10 basal mRNA level was higher in cells with high migratory and invasive potential. Similar to cell lines, higher expression of CXCR6 and CXCL16, as well as ADAM10, was observed in tissue, which showed a positive correlation with tumor stage. These results suggest the clinical and biological significance of CXCR6-CXCL16 axis in the pathogenesis of ovarian cancer. Therefore, therapeutics directed to the CXCR6-CXCL16 axis may provide better therapeutic outcome and overall survival.

Citation Format: Hina Mir, Neeraj Kapur, James W. Lillard, Shailesh Singh. Role of CXCL16 and ADAM10 in ovarian cancer pathogenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1924.
Abstract 1953: Expression and activity of MT1-MMP in endothelial cells is regulated by Semaphorin 4D
Authors: Bugshan Amr , Khoury Zaid , Buhamrah Asma , Basile John R.
Published: August 2018

The semaphorins and plexins, originally shown to control axon growth cone guidance, are now known to influence many aspects of cell adhesion and migration. Our group and others have demonstrated that carcinomas over express Semaphorin 4D (S4D), particularly under conditions of hypoxia, for the purpose of supporting tumor-induced angiogenesis. However, S4D is a transmembrane protein that must be proteolytically cleaved to attract endothelial cells into a malignancy, a process that in head and neck squamous cell carcinoma (HNSCC) is controlled by membrane type 1-matrix metalloproteinase (MT1-MMP). We wanted to test the possibility that S4D acts through its receptor, Plexin-B1 (PB1), to enhance activity of endothelial cell MT1-MMP, facilitating extracellular matrix degradation and further promoting angiogenesis. We observed upregulated transcription, expression and cell surface localization of MT1-MMP in endothelial cells treated with S4D, occurring in a PB1, RhoA and NF-κB-dependent manner. We also demonstrated that S4D-induced endothelial cell collagen degradation, migration and capillary tube formation are suppressed when PB1 is silenced or its downstream effectors RhoA and NF-κB are inhibited. Endothelial MT1-MMP contributes to the ability of these cells to digest their way through the basement membrane and extracellular matrix, a requirement for the creation of the vascular networks that supply a developing tumor with oxygen and nutrients and allow it access to the systemic circulation for metastasis. These results demonstrate that S4D promotes angiogenesis at multiple levels, and suggest that it would be a valid target for anti-angiogenic intervention in the treatment of solid malignancies.

Citation Format: Amr Bugshan, Zaid Khoury, Asma Buhamrah, John R. Basile. Expression and activity of MT1-MMP in endothelial cells is regulated by Semaphorin 4D [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1953.
Abstract 1955: Suppression of hormone receptor-positive and triple-negative breast cancers by new inhibitors of the transcription factor FOXM1
Authors: Laws Mary J. , Kim Sung Hoon , Ziegler Yvonne , Bindman Noah , Gong Ping , Guillen Valeria Sanabria , Yasuda Mayuri , Singh Divya , El-Ashry Dorraya , Katzenellenbogen John A. , Katzenellenbogen Benita S.
Published: August 2018

The transcription factor FOXM1 is up-regulated and overexpressed in aggressive, therapy-resistant forms of hormone receptor-positive and triple negative breast cancers, and is associated with less good patient survival. FOXM1 pathway signaling is also a key driver in other aggressive cancers including those in prostate, lung, ovary, and gastrointestinal tract, and in glioblastoma. Therefore, our goal has been to identify FOXM1 inhibitors effective in suppressing breast cancer proliferation both in vitro and in vivo and displaying potency, selectivity and good pharmacokinetic properties for in vivo efficacy. We screened large chemical libraries of over 130,000 compounds from which several were identified and characterized as potential FOXM1 inhibitors. These were then chemically modified and optimized for potency and good pharmacokinetic properties. The best were shown to effectively suppress the proliferation of FOXM1 expressing breast cancer cells, decrease the expression of FOXM1 and FOXM1- regulated genes, and inhibit the chromatin binding of FOXM1 to FOXM1 binding sites in these genes. Inhibitors that had long half-lives (t1/2 greater than 24H) were selected for studies in experimental preclinical mouse models. One inhibitor had good oral efficacy in suppressing the growth of FOXM1-containing breast tumors in NOD-SCID-gamma (NSG) mice, and several others had good efficacy in tumor suppression by subcutaneous but not oral administration. Our findings identify and characterize several compounds that effectively antagonize FOXM1 actions and tumor growth that may be suitable for further clinical evaluation in targeting aggressive breast cancers driven by FOXM1.

Citation Format: Mary J. Laws, Sung Hoon Kim, Yvonne Ziegler, Noah Bindman, Ping Gong, Valeria Sanabria Guillen, Mayuri Yasuda, Divya Singh, Dorraya El-Ashry, John A. Katzenellenbogen, Benita S. Katzenellenbogen. Suppression of hormone receptor-positive and triple-negative breast cancers by new inhibitors of the transcription factor FOXM1 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1955.
Abstract 1966: A novel small-molecule compound targeting PBX1-DNA interaction impedes cancer cell survival and carboplatin resistance
Authors: Shen Yao-An , Jung Jin , Rahmanto Yohan Suryo , Selleri Licia , Shih Ie-Ming , Chuang Chi-Mu , Wang Tian-Li
Published: August 2018

Pre-B-cell leukemia homeobox-1 (PBX1), a transcriptional factor and downstream effector of Notch signaling pathway, plays pivotal roles in a wide spectrum of tumors, as well as developmental, inflammatory, autoimmune, and neurodegenerative disorders. Exploiting the crystal structure of the Pbx1-DNA complex, we developed a novel small-molecular inhibitor T417 that can directly block Pbx1-binding to DNA, unlike other existing compounds that interfere with protein-protein interactions. When T417 docks into the hydrophobic pocket of Pbx1 protein, the small molecule can dampen PBX1 transcription activity by hindering its binding to the promoter regions of PBX1 downstream target genes. Intriguingly, the amount of PBX1 expression in cells can dictate its response to T417. Increment of PBX1 expression is found in the high-grade serous carcinoma (HGSC) and carboplatin-resistant (CR) cells, and its expression is generally low in normal tissues as compared to the transformed tissues, making it such an arguably unique therapeutic target in ovarian cancer cells. This expression pattern illustrates the very minimal toxicity of T417 on normal tissues and organs in animal models, while it imposed in vitro and in vivo detrimental effects toward HGSC and CR cells. Besides, T417 holds synergistic cytotoxic effects with DNA damage-related drugs including PARP inhibitor and platinum-based drug. As PBX1 was shown to participate in maintaining cancer stem cell (CSC)-like phenotypes and promoting resistance to antitumor drugs, T417 is able to hammer out the stemness traits of CR cells to revert to a differentiated status through tacking PBX1 signaling cascade. The novel PBX1-targeting compound selectively interferes with PBX1-binding to DNA, which potentially points to powerful therapeutics and broad applications for the treatment of different human malignancies and stem cell therapy.

Citation Format: Yao-An Shen, Jin Jung, Yohan Suryo Rahmanto, Licia Selleri, Ie-Ming Shih, Chi-Mu Chuang, Tian-Li Wang. A novel small-molecule compound targeting PBX1-DNA interaction impedes cancer cell survival and carboplatin resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1966.
Abstract 1968: A novel glucocorticoid receptor (GR) antagonist overcomes GR-mediated chemoresistance in triple-negative breast cancer
Authors: Jahchan Nadine , Zhou Haiying , Kong Wayne , Weeney Dan Mc , Tracy Ted , Stice James , Sutimantanapi Dena , Chen Chelsea , Huang Tom , Rew Yosup , Du Xiauhui , Zavorotinskaya Tatiana , Sun Daqing , Ye Qiuping , Jackson Erica , Fantin Valeria
Published: August 2018

The glucocorticoid receptor (GR) is a member of the nuclear receptor superfamily, which is activated by its endogenous steroid hormone ligand cortisol, and by synthetic glucocorticoids such as dexamethasone. Several preclinical studies have shown that GR mediates resistance to both targeted therapies and conventional chemotherapies in a variety of epithelial cancers including prostate, lung, bladder, renal, ovarian and triple-negative breast cancers (TNBC) (Gassler et al., 2005; Li et al., 2017; Zhang et al., 2007). In TNBC, both GR activation and a disrupted cortisol secretion cycle are associated with chemotherapy resistance, increased disease recurrence and poor prognosis (Pan et al., 2011; Skor et al., 2013). Therefore a molecule that inhibits GR activation could attenuate the development of therapy resistance and improve patient outcomes. We have developed novel GR inhibitors that effectively block GR transcriptional activity in cells by competing for ligand binding and by blocking GR-coactivator interactions. In vitro, treatment of TNBC cells with the GR antagonist OP-3713 blocks GR transcriptional activity and enhances the efficacy of chemotherapeutic agents. In rodents the predominant glucocorticoid is corticosterone (Siswanto et al., 2008), which is a weak agonist of human GR. Therefore, to fully activate GR in human xenograft cancer models it is necessary to provide exogenous cortisol. Using xenograft models of TNBC, we find that tumors grown in mice with physiologically relevant circulating cortisol levels to activate GR are significantly less sensitive to chemotherapy than those grown in the absence of cortisol. Furthermore, inhibition of GR by OP-3713 prevents tumor relapse following chemotherapy treatment. We have begun to elucidate the mechanisms by which GR mediates chemoresistance in TNBC, and the basis for the reversal by OP-3713. Our findings underscore the important role of GR as a mediator of resistance in TNBC and highlight the therapeutic potential of GR inhibitors in combination with clinically relevant chemotherapeutic agents.

Citation Format: Nadine Jahchan, Haiying Zhou, Wayne Kong, Dan Mc Weeney, Ted Tracy, James Stice, Dena Sutimantanapi, Chelsea Chen, Tom Huang, Yosup Rew, Xiauhui Du, Tatiana Zavorotinskaya, Daqing Sun, Qiuping Ye, Erica Jackson, Valeria Fantin. A novel glucocorticoid receptor (GR) antagonist overcomes GR-mediated chemoresistance in triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1968.
Abstract 1992: Epigenetic and transcriptomic profiling of mammary gland development and tumor models disclose regulators of cell state plasticity
Authors: Dravis Christopher , Chung Chi-Yeh , Wahl Geoff
Published: August 2018

Cell state reprogramming during tumor progression significantly contributes to the genesis of intra-tumoral heterogeneity. Discovering how cell state plasticity is specified during normal mammary development, and how this relates to breast cancer, could provide new treatment approaches. We used chromatin accessibility assays and transcriptional profiling to infer lineage potential within distinct normal mammary cell populations. We show that fetal and adult basal cells exhibit features consistent with multi-lineage differentiation potential. SOX family transcription factor DNA-binding motifs were enriched in the open chromatin of stem/progenitor cells, implicating SOX factors in mammary cell plasticity. We provide evidence that SOX10 expression correlates with multiple indicators of cell state plasticity, and that it directly contributes to tumor development in multiple animal models. Strikingly, we show that SOX10-positive tumor cells uniquely exhibit neural crest cell features, and that SOX10 binds to genes that regulate neural crest cell identity. Collectively, these data help to resolve conflicts concerning cell fate and cell potential in the mammary cell hierarchy, reveal that SOX10 is a plasticity factor driving mammary tumor progression, and demonstrate the remarkable scope of cell state reprogramming that can occur during tumorigenesis.

Citation Format: Christopher Dravis, Chi-Yeh Chung, Geoff Wahl. Epigenetic and transcriptomic profiling of mammary gland development and tumor models disclose regulators of cell state plasticity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1992.
Abstract 1999: Study of CD44 variant 6 (CD44v6) in prostate cancer chemo-/radio resistance in vivo
Authors: Ni Jie , Cozzi Paul , Beretov Julia , Bucci Joseph , Graham Peter , Li Yong
Published: August 2018

Background: Chemo-/radio-resistance is an important reason for prostate cancer (CaP) progression and metastasis. CD44 is a well-documented cancer stem cell (CSC) biomarker, and one of its variants, CD44 variant 6 (CD44v6) is closely associated with aggressive behaviour and correlates with poor prognosis in a variety of human cancers. Our previous study has demonstrated increased expressions of CD44v6 in metastatic CaP cell lines and human CaP tissues, which was associated with CaP progression and chemo-/radio-resistance in vitro. However, the role of CD44v6 in CaP progression and therapeutic resistance in vivo is still uncertain.

Aim: The aim of this study was to investigate the role of CD44v6 in CaP development and chemo-/radioresistance as well as underlying pathways in vivo, and find whether it is a suitable therapeutic target for CaP therapy.

Methods: CD44v6 gene was knocked down (KD) in PC-3M CaP cell line using short hairpin RNA (shRNA). Subcutaneous (s.c.) and orthotopic CaP animal models were established using PC-3M-CD44v6-KD and PC-3M-CD44v6-scramble (scr) control cells, to assess the effect of CD44v6 on CaP tumourigenesis, chemotherapy (docetaxel) response and radiation response. Signal transduction proteins in PI3K/Akt/mTOR pathway (Akt, p-Akt, mTOR and p-mTOR) as well as proliferation and apoptosis makers were assessed by immunohistochemistry in xenografts from both animal models.

Results: Both s.c. and orthotopic xenografts from PC-3M-CD44v6-KD cells displayed supressed tumour growth and increased responsiveness to docetaxel (40mg/kg) and radiation (2Gy/day for 4 consecutive days) compared to control xenografts from PC-3M-CD44v6-scr cells in NOD/SCID male mice. Down-regulation of the PI3K/Akt/mTOR pathway proteins (p-Akt and p-mTOR), proliferation marker (Ki-67) and angiogenesis marker (CD31), as well as up-regulation of apoptotic responses (cleaved Caspase-3) to chemotherapy, DNA damage responses (γ-H2AX) to radiation were found in PC-3M-CD44v6-KD s.c. xenografts, respectively.

Conclusions: CD44v6 is actively involved in CaP tumorigenesis and treatment responses to chemo-/radio-therapy via PI3K/Akt/mTOR signalling pathway in in vivo mouse models and holds promise as a therapeutic target for the treatment of CaP.

Key words: CD44v6, prostate cancer, chemo-/radio-resistance, animal model, metastasis

Citation Format: Jie Ni, Paul Cozzi, Julia Beretov, Joseph Bucci, Peter Graham, Yong Li. Study of CD44 variant 6 (CD44v6) in prostate cancer chemo-/radio resistance in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1999.
Abstract 2002: Ganoderma lucidum extract (GLE) reduces stem cell markers in triple-negative breast cancer models via STAT3 regulation
Authors: Rios Tiffany J. , Marti Alicia , Ortiz Gabriela , Martínez-Montemayor Michelle M.
Published: August 2018

Triple-negative breast cancer (TNBC) is a subtype of cancer described by the lack of estrogen receptor, progestogen receptor, and HER2 receptor. It accounts for approximately 15-20% of all breast cancer (BC) cases worldwide. TNBC aggressiveness might be explained by the presence of BC stem cells (BCSCs), which are a subpopulation of cancer cells involved in tumor initiation, metastasis, and therapy resistance. Interestingly, the signal transducer and activator of transcription 3 (STAT3) participates in the development and progression of BCSCs, but its role in TNBC progression remains unclear. Moreover, BCSCs can be identified by the CD44+/CD24- and ALDH+ phenotype, which correlates with a worse prognosis in TNBC patients. Furthermore, CSCs can be characterized based on the expression of transcription factors involved in stemness (Nanog, Sox2, and Oct4A), where activation of STAT3 leads to enhanced Nanog, Oct4 and Sox2 expression. Importantly, a major challenge arises to develop nontoxic targeted therapies to improve the outcome of TNBC patients. In this regard, our laboratory investigates the role of Ganoderma lucidum extract (GLE), a medicinal mushroom commonly used in complementary and alternative medicine. We hypothesize that GLE will decrease stem cell properties via STAT3 regulation in TNBC cells. Our in vitro results demonstrate that GLE significantly downregulates STAT3 and JAK2 in SUM-149 and MDA-MB-231, TNBC cell lines. In addition, GLE significantly decreases the secretion of IL-6 at 24hr in MDAMB231 cells. Further flow cytometry results show that GLE significantly decreases the CD44+/CD24- population at 24hr and 72hr in MDA-MB-231 cells. In this regard, GLE significantly decreases the expression of ALDH at 24hr and 72hr in MDAMB231 cells. Moreover, GLE decreases the expression of Nanog at 24hr, and all three transcription factors at 72hr. Additionally, our in vivo studies demonstrate that GLE significantly decreases tumor volume of mice injected with CD44+/CD24- sorted cells of the MDA-MB-231 cell line. Finally, tumor weight of GLE treated mice was marginally significantly lower (p=0.053) compared to vehicle. We can conclude that GLE decreases stemness of TNBC via STAT3 regulation.

Citation Format: Tiffany J. Rios, Alicia Marti, Gabriela Ortiz, Michelle M. Martínez-Montemayor. Ganoderma lucidum extract (GLE) reduces stem cell markers in triple-negative breast cancer models via STAT3 regulation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2002.
Abstract 2009: Breast cancer stem cells are associated with HER2-mediated radioresistance and the molecular subtype conversion of HER2-negative breast cancer
Authors: Kim Jae-Sung
Published: August 2018

Although it has been proposed that the benefits of HER2-targeted therapy in HER2-negative breast cancer are associated with molecular subtype conversion, the underlying mechanism and the clinical biomarkers are unclear. Herein, we showed that breast cancer stem cells (BCSCs) mediate HER2 subtype conversion and radioresistance in HER2-negative breast cancer cells and evaluated serum HER2 as a clinical biomarker for HER2 subtype conversion. We found that the CD44+/CD24-/low BCSCs from HER2-negative breast cancer cells overexpressed HER2/EGFR and showed the radioresistant phenotype. In addition, we showed that trastuzumab treatment sensitized the radioresistant phenotype of the CD44+/CD24-/low cells with decreased levels of HER2/EGFR, which suggested that HER2-targeted therapy in HER2-negative breast cancer may be effective by targeting BCSCs that overexpress HER2/EGFR. Importantly, our clinical data showed that serum HER2 could be a clinical biomarker for the evaluation of HER2 subtype conversion in recurrent HER2-negative breast cancer patients. Therefore, our data provide in vitro and in vivo evidence for the molecular subtype conversion of HER2-negative breast cancer.

Citation Format: Jae-Sung Kim. Breast cancer stem cells are associated with HER2-mediated radioresistance and the molecular subtype conversion of HER2-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2009.
Abstract 2021: The CXCL12/CXCR4 axis drives epithelial-mesenchymal transition in renal cell carcinoma
Authors: Zhilin-Roth Alisa , Macoska Jill A.
Published: August 2018

Introduction. Renal cell carcinoma (RCC) is the one of the most common cancers diagnosed in adult men with more than 40000 new cases annually. Recurrence or metastasis of the disease occurs in more than 30% of patients and death from disease occurs in most of these patients due to limited therapeutic options. Clearly, a better understanding of factors contributing to RCC metastasis might improve therapeutic development and patient outcomes. One of the steps required for tumor cell progression from localized disease to metastatic disease is the acquisition of invasive abilities through epithelial to mesenchymal transition (EMT). EMT promotes loss of epithelial markers by downregulation of E-cadherin, gain of mesenchymal markers like Vimentin, and N-cadherin, and cytoskeletal rearrangement that enables cells to leave the primary site and intravasate into the blood or lymphatic systems and thereby colonize distant sites. Metastasis and colonization are highly directed mechanisms in which cancer cells migrate toward specific preferred organs that express specific protein receptors. One of these receptors is CXCR4, which is upregulated in advanced cancer including RCC and is correlated with poor survival. In this study we explored the hypothesis that CXCR4/CXCL12 signaling promotes migratory ability by inducing EMT in vitro in the RCC cell lines Caki-2 and 786-0.

Methods. To pursue these studies we utilized in vitro mammalian cell culture, cell proliferation (WST) assays, cell migration (scratch) assays, and protein analysis methods including immunoblot and immunofluorescence.

Results. These studies showed that RCC cell lines express CXCR4 that is activated by CXCL12 to induce cellular proliferation and promote a wound healing migratory response dependent on EMT cytoskeletal rearrangement by Rho GTPases. Moreover, CXCR4/CXCL12 induces down-regulation of E-cadherin, up-regulation of vimentin, N-cadherin and the upregulation of EMT transcription factors SLUG/SNAIL, consistent with EMT signaling activation. Lastly, CXCR4/CXCL12 activation promotes phosphorylation of AKT and ERK, suggesting that these signaling pathways are coupled to CXCR4/CXCL12-mediated RCC progression.

Conclusions. Our findings suggest that CXCR4/CXCL12 activation in RCC has a pivotal role in EMT induction by the acquisition of a migratory and invasive phenotype. Understanding the underlying signaling pathways employed by the CXCL12/CXCR4 axis may shed new light on the migration/ invasion mechanisms that allow RCC cells to spread to distant organs and assist with the design and testing of new therapeutic strategies to treat advanced metastatic RCC.

Citation Format: Alisa Zhilin-Roth, Jill A. Macoska. The CXCL12/CXCR4 axis drives epithelial-mesenchymal transition in renal cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2021.