bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 4067: BPM31510, a clinical stage metabolic modulator demonstrates therapeutic efficacy in an in vivo C6 rat glioma model and synergizes with temozolomide
Authors: Gesta Stephane , Nagpal Semma , Dadali Tulin , Merchant Milton , Jan Taichang , Diers Anne R. , Kiebish Michael , Jiminez Joaquin , Vishnudas Vivek K. , Narain Niven R. , Sarangarajan Rangaprasad , Recht Lawrence
Published: July 2017

BPM31510, a parenteral nanodispersion of ubidecarenone that is in clinical testing for solid tumors, effectuates an anti-cancer effect in highly metabolic cancers by eliciting an anti-Warburg effect. Intraperitoneal (i.p.) administration of BPM31510 reverses paraplegia in a rat CNS leukemia model demonstrating the bioavailability of the drug to the central nervous system. The study describes data demonstrating the therapeutic utility of BPM31510 in glioblastoma multiforme (GBM). BPM31510 decreased cell proliferation rates in patient derived GBM cell lines compared to temozolamide (TMZ), pretreatment with BPM31510 followed by TMZ challenge was associated with significant synergy in reducing cell proliferation compared to monotherapy. In a C6 glioma allograft rat model treatment with BPM31510 alone (n=30/group) (i.p., 50mg/kg, b.i.d) increased overall survival compared to untreated control group. BPM31510 in combination with procarbazine (oral, 60mg/kg; d 8, 21) and vincristine (IV, 1.4mg/kg; d 8, 29) significantly improved overall survival compared to BPM31510 alone or chemotherapy. Furthermore, long term survival was achieved in four of twenty rats with C6 gliomas receiving BPM31510 doses between 10 and 50 mg/kg compared with none treated with either vehicle or irradiation (P < 0.02, Fisher exact test). Interestingly, the long term survival persisted for over two months after all treatment was discontinued; MR imaging confirmed the presence of static masses in these long term survivors. Collectively, the data demonstrate that BPM31510 has a robust effect in a preclinical model of GBM. Intravenous BPM31510 is currently in Phase 1/2 clinical trial for TMZ+BEV refractory GBM patients.

Citation Format: Stephane Gesta, Semma Nagpal, Tulin Dadali, Milton Merchant, Taichang Jan, Anne R. Diers, Michael Kiebish, Joaquin Jiminez, Vivek K. Vishnudas, Niven R. Narain, Rangaprasad Sarangarajan, Lawrence Recht. BPM31510, a clinical stage metabolic modulator demonstrates therapeutic efficacy in an in vivo C6 rat glioma model and synergizes with temozolomide [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 4067. doi:10.1158/1538-7445.AM2017-4067
Abstract 4068: HH-002, a derivative of Homoharringtonine, show promsing in diverse cancer models in preclinical characterization
Authors: Rui Hank
Published: July 2017

Homoharringtonine (HHT) is an anti-cancer drug used to treat imatinib resistant CML, and a reversible inhibitor of translation acting upon the early steps in polypeptide chain elongation. BS-HH-002.SA is a derivative of HHT. BS-HH-002.SA was shown to decrease the phosphorylation of Janus protein tyrosine kinase 2 (JAK2) as well as downstream targets, such as signal transducers and activators of transcription 3 and 5 (STAT3 and STAT 5), it also reduced Myeloid cell leukemia-1 (Mcl-1) protein level significantly and resulted in apoptosis. Evaluation of BS-HH-002.SA efficacy. was test in HEL, an erthroleukemia cell line carrying a JAK2V617F mutation which is seen in 90% of patients with polycythemia vera (PCV) and half of those with essential thrombocythemia or primary myelofibrosis. HH-002.SA showed was highly potent (at low nM concentration) to HEL. Efficacy of BS-HH-002 was tested in a recombinant human erythropoietin injection (rhEpo)-induced murine model of polycythemia Vera, Treatment with BS-HH-002.SA BID for 4 days showed a significant inhibitory effect on rhEpo induced increase in reticulocytes, hematocrit and splenomegaly, as well as in red blood cell, white blood cell and platelet counts. Furthermore, histology evaluations revealed that BS-HH-002.SA exerted an inhibitory effect on rhEpo induced extramedullary hematopoiesis in spleen, and decreased cellularity in bone marrow with more predominant effect on erythroid cells than on myeloid cells. Also, BS-HH-002.SA also show potent in vitro and in vivo efficacy in pancreatic cancer cell line KP-4 and non-small cell lung cancer (NSCLC) NCI-H1975, BS-HH-002.S inhibited STAT3 Tyrosine 705 phosphorylation and reduced anti-apoptotic proteins expression Mcl-1 protein levels in both two cancer cell lines.

Note: This abstract was not presented at the meeting.

Citation Format: Hank Rui. HH-002, a derivative of Homoharringtonine, show promsing in diverse cancer models in preclinical characterization [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 4068. doi:10.1158/1538-7445.AM2017-4068
Abstract 4070: Salternamide A, a marine natural product, suppresses hypoxia-induced accumulation of HIF-1α and induces apoptosis in human colorectal cancer cells
Authors: Bach Duc-Hiep , Byun Woong Sub , Kim Seong-Hwan , Hong Ji-Young , Park Hyen Joo , Oh Dong-Chan , Lee Sang Kook
Published: July 2017

Hypoxia inducible factor-1α (HIF-1α) is an essential regulator of the cellular response to low oxygen concentrations, activating a broad range of genes that provide adaptive responses to oxygen deprivation. HIF-1α is overexpressed in various cancers and therefore represents a considerable chemotherapeutic target. Salternamide A (SA), a novel small molecule that is isolated from a halophilic Streptomyces sp., is a potent cytotoxic agent against a variety of human cancer cell lines. However, the mechanisms by which SA inhibits tumor growth remain to be elucidated. In the present study, we demonstrate that SA efficiently inhibits the hypoxia-induced accumulation of HIF-1α in a time- and concentration-dependent manner in various human cancer cells. In addition, SA suppresses the upstream signaling of HIF-1α, such as PI3K/Akt/mTOR, p42/p44 MAPK, and STAT3 signaling under hypoxic conditions. Furthermore, we found that SA induces cell death by stimulating G2/M cell cycle arrest and apoptosis in human colorectal cancer cells. Taken together, SA was identified as a novel small molecule HIF-1α inhibitor from marine natural products and is potentially a leading candidate in the development of anticancer agents.

Acknowledgment

This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean Government (MEST) (MRC No. 2009-0083533)

Citation Format: Duc-Hiep Bach, Woong Sub Byun, Seong-Hwan Kim, Ji-Young Hong, Hyen Joo Park, Dong-Chan Oh, Sang Kook Lee. Salternamide A, a marine natural product, suppresses hypoxia-induced accumulation of HIF-1α and induces apoptosis in human 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 4070. doi:10.1158/1538-7445.AM2017-4070
Abstract 409: Genome engineering to generate models of chromosome arm-level aneuploidies in lung carcinoma
Authors: Taylor Alison M. , Ha Gavin , Shih Juliann , Zhang Xiaoyang , Francis Joshua M. , Meyerson Matthew
Published: July 2017

Almost 90% of tumors are aneuploid and have arm- or whole- chromosome level copy number changes. Arm-level copy number alterations cluster by tumor type, suggesting that specific arm-level changes are influenced by cell type. Systematic methods of generating copy number changes on a particular chromosome have not been tested, leaving the effects of specific aneuploidies in cancer unclear. The most frequent genomic alteration in lung squamous cell carcinomas (SCCs) is loss of chromosome 3p. This alteration occurs in 90% of lung SCCs, and covers the entire length of the chromosome arm. Over two-thirds of 3p genes show significantly decreased expression. However, the phenotypic effects of 3p loss in tumorigenesis are not known.

We used the CRISPR-Cas9 system to generate double-strand breaks (DSBs) and produce partial aneuploidies of arm-level loss. We have targeted guide RNAs adjacent to centromeric satellite-repeat sequences on chromosome arm 3p. At this location, we induced homologous recombination with a selection cassette and artificial telomere. We have successfully isolated almost 90 clones of immortalized lung epithelial cells with deletion of the 3p arm, with 8 validated by whole genome sequencing. Consistent with patient data, expression of 3p genes is also decreased upon deletion. Phenotypic characterization revealed that cells with chromosome 3p deletion proliferate more slowly than their siblings. 3p deleted cells show increased G1 arrest, but do not undergo increased apoptosis or cell death. We are currently testing 3p loss in combination with other frequent SCC alterations, such as SOX2 and TP63 gain. We have also identified expression changes in trans, outside of chromosome 3p. These studies provide a robust model that will address a gap in our understanding of aneuploidy in cancer by using targeted endonuclease technology to create models of partial aneuploidies. Future work will include investigation of how different chromosomal changes contribute to cancer formation, which will have implications on our understanding of tumorigenesis.

Citation Format: Alison M. Taylor, Gavin Ha, Juliann Shih, Xiaoyang Zhang, Joshua M. Francis, Matthew Meyerson. Genome engineering to generate models of chromosome arm-level aneuploidies in lung carcinoma [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 409. doi:10.1158/1538-7445.AM2017-409
Abstract 4091: AKT can modulate the in vitro response of HNSCC cell to irreversible EGFR inhibitors
Authors: Silva-Oliveira Renato José , Melendez Matias , Martinho Olga , Zanon Maicon Fernando , Viana Luciano de Souza , Carvalho André Lopes , Reis Rui Manuel
Published: July 2017

Epidermal growth factor receptor (EGFR) is overexpressed in up to 90% of head and neck squamous cell carcinoma (HNSCC) tumors. Cetuximab is the first targeted (anti-EGFR) therapy approved for the treatment of patients with locally advanced HNSCC. However, its efficacy is limited due to primary and secondary resistance, and there is no predict biomarkers of response. New generation of EGFR inhibitors with pan HER targeting and irreversible action, such as afatinib and allitinib represents a significant therapeutic promise in HNSCC treatment. In this study, we intend to compare the potential cytotoxicity of two irreversible anti-EGFR inhibitors (afatinib and allitinib) with cetuximab and to identify potential predictive biomarkers of response in a panel of HNSCC cell lines. The mutational analysis in hotspot regions of EGFR, KRAS, NRAS, PIK3CA and PTEN in the eight HNSCC cell lines revealed an EGFR mutation (p.H773Y) and gene amplification in the HN13 cells, and KRAS mutation in the JHU-28 cell line. According to the growth inhibition score (GI), allitinib was the most cytotoxic drug, followed by afatinib and finally cetuximab. The HN13 cell line exhibited a less responsive behavior to all drugs assessed, and interestingly, also displayed the higher levels of AKT phosphorylation. Therefore, we further performed drug combinations and found that with anti-AKT agent (MK2206), afatinib and allitinib, but not cetuximab, sensitivity was restored. Additionally, AKT1gene editing in afatinib and allitinib-treated cell lines showed that AKT1 silencing-induced cell line decreased viability and increased cytotoxicity through caspases 3/7activation.Additionally, in silico analysis of TCGA database showed that AKT1 overexpression was present in 14.7% (41/279) of HNSCC cases, and was associated with perineural invasion in advanced stage. In conclusion, allitinib presented a greater cytotoxic profile when compared to afatinib and cetuximab, and the AKT pathway constitutes a predictive marker of allitinib response. Importantly, in allitinib and afatinib-resistant cases, the pharmacological combination with AKT inhibitors could restore response and increase treatment success.

Citation Format: Renato José Silva-Oliveira, Matias Melendez, Olga Martinho, Maicon Fernando Zanon, Luciano de Souza Viana, André Lopes Carvalho, Rui Manuel Reis. AKT can modulate the in vitro response of HNSCC cell to irreversible EGFR inhibitors [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 4091. doi:10.1158/1538-7445.AM2017-4091
Abstract 4093: t-Darpp stimulates protein kinase A activity by interacting with its RI regulatory subunit
Authors: Theile Dirk , Geng Shuhui , Denny Erin , Momand Jamil , Kane Susan E.
Published: July 2017

t-Darpp is the truncated form of the dopamine- and cAMP-regulated phosphoprotein of 32 kDa (Darpp-32) and has been demonstrated to confer resistance to trastuzumab, a Her2-targeted anticancer agent, via sustained signaling through the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/Akt pathway. t-Darpp over-expression results in enhanced activity of protein kinase A (PKA), but the mechanism of t-Darpp-mediated PKA activation is poorly understood. In the PKA holoenzyme, when the catalytic subunits are bound to regulatory subunits RI or RII, kinase activity is inhibited. We investigated PKA activity and holoenzyme composition in cell lines that over-express t-Darpp (SK.tDrp) or a T75A phosphorylation mutant (SK.tDrp.T75A), as well as an empty vector control cell line (SK.empty). We also evaluated protein-protein interactions between t-Darpp and PKA catalytic (PKAc) or regulatory subunits RI and RII in those cell lines. Whereas SK.tDrp cells had elevated PKA activity, SK.tDrp.T75A cells did not. In agreement with the effects on activity, a proximity ligation assay showed that SK.tDrp cells, but not SK.tDrp.T75A cells, had diminished association of RI with PKAc. Moreover, t-Darpp was seen to bind directly to RI in co-immunoprecipitation studies. Cells that express both Darpp-32 and t-Darpp had PKA activity levels and RI-PKAc association that were similar to control SK.empty cells. This is consistent with our published findings that Darpp-32 reverses t-Darpp’s effects on trastuzumab resistance and CREB DNA binding activity (downstream of PKA). Taken together, our data suggest that T75 phosphorylation is crucial for t-Darpp-mediated PKA activation and this activation appears to occur through direct binding to RI and release of RI from PKAc. The t-Darpp-RI interaction could be a druggable target to reduce PKA activity in drug-resistant cancer.

Citation Format: Dirk Theile, Shuhui Geng, Erin Denny, Jamil Momand, Susan E. Kane. t-Darpp stimulates protein kinase A activity by interacting with its RI regulatory subunit [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 4093. doi:10.1158/1538-7445.AM2017-4093
Abstract 4097: Src-met signaling confers apoptosis resistance to the combination of BKM120 and erlotinib in head and neck cancer
Authors: Amin A.R.M. Ruhul , Anisuzzaman Abu , Haque Abedul , Chen Zhuo , Shin Dong
Published: July 2017

Purpose: Molecularly targeted agents will play a major role in the next generation of personalized cancer therapies. However, intrinsic and acquired resistance to targeted agents poses challenges to the success of such treatments. The purpose of the current study was to investigate the intrinsic resistance of head and neck cancer (HNC) cell lines to apoptosis induced by the combination of EGFR inhibitor erlotinib and PI3K inhibitor BKM120.

Methods: In a panel of 10 malignant and 1 premalignant HN cell lines, we evaluated cell growth inhibition (by SRB assay), IC50, combination index, dose reduction index (by CalcuSyn Software), and apoptosis (by Annexin-V staining). Protein expression levels were measured by Western blotting. Small molecule chemical inhibitors and siRNA-mediated knockdown strategies were used to inactivate and shut down the expression of the relevant proteins, respectively.

Results: Single targeting of EGFR with erlotinib or PI3K with BKM120 (pan-PI3K inhibitor) suppressed cellular growth without inducing significant apoptosis. Co-targeting EGFR and PI3K demonstrated in vitro synergy in all except one cell line (based on combination index and dose reduction index) and more effectively inhibited HNC xenograft growth in vivo. The combination of erlotinib and BKM120 induced variable apoptosis: some cell lines were very sensitive (Tu686, 686LN, 93-VU-147T), some moderately (Fadu, SqCCy1, 1483, UMSSC90) and others were resistant (UD-SCC2, MSK-LEUK1, JHU022) to apoptosis induction. JHU022 and 1483 cell lines expressed very high levels of p-cMet. Targeting cMet with the small molecule inhibitor crizotinib or siRNA rendered these cell lines highly sensitive to erlotinib and BKM120 induced apoptosis. Moreover, inhibition of Src family kinases with the small molecule inhibitor dasatinib or with c-Src-specific siRNA inhibited p-cMet. In addition, inhibition of SFK in these cell lines conferred sensitivity to erlotinib and BKM120 induced apoptosis.

Conclusions: Our results strongly suggest that co-targeting of EGFR and PI3K has synergistic activity, is effective in vivo, and induces apoptosis of some HNC cell lines. Two of the resistant cell lines express a high level of p-cMet as a downstream target of SFK, which confers resistance of these cells to the combination of erlotinib and BKM120.

Citation Format: A.R.M. Ruhul Amin, Abu Anisuzzaman, Abedul Haque, Zhuo Chen, Dong Shin. Src-met signaling confers apoptosis resistance to the combination of BKM120 and erlotinib in head and neck 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 4097. doi:10.1158/1538-7445.AM2017-4097
Abstract 41: An Antibody Drug Conjugate targeting HER-3 demonstrates promising antitumor efficacy in a wide range of human cancer
Authors: Sala Gianluca , Iezzi Manuela , Lamolinara Alessia , Capone Emily , Iacobelli Stefano , Sauniere Jean-Fred , Ponziani Sara , Giansanti Francesco , Ippoliti Rodolfo
Published: July 2017

The HER-3 receptor is emerging as an attractive molecule in therapeutics because of its overexpression across many human cancers and because of its role in in several compensatory processes that underlay emergence of resistance to certain cancer drugs. In this study, we present evidence of the preclinical efficacy of a novel Antibody-Drug Conjugate (ADC) targeting HER-3. It consists of a humanized HER-3 monoclonal antibody (mAb EV20), which recognizes the HER-3 extracellular domain, conjugated to different payloads (HER-3-ADC)s. In HER-3 expressing cancer cell lines, these HER-3-ADCs demonstrated a powerful, specific and target-dependent killing activity. High expression levels of HER-3 in tumor cells correlated with efficient internalization, efficacy, and cytotoxic effects in vitro. Efficacy studies demonstrated that HER-3-ADCs treatment leads to a long lasting tumor growth inhibition of cell line-based models of human head and neck, breast, pancreatic, prostatic, lung, stomach cancers and melanoma. Overall, these findings validate HER-3 as an attractive therapeutic target in multiple solid tumors and support further clinical development and application of HER-3 targeting ADCs.

Citation Format: Gianluca Sala, Manuela Iezzi, Alessia Lamolinara, Emily Capone, Stefano Iacobelli, Jean-Fred Sauniere, Sara Ponziani, Francesco Giansanti, Rodolfo Ippoliti. An Antibody Drug Conjugate targeting HER-3 demonstrates promising antitumor efficacy in a wide range of human 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 41. doi:10.1158/1538-7445.AM2017-41
Abstract 4113: Acquired resistance to cetuximab is mediated by HER3 activation in head and neck squamous cell carcinoma
Authors: Yang Yeon Ju , Cho Min Hee , Oh Yoo Jung , Kim Da Hee , Kim Jung Min , Byeon Hyung Kwon , Ban Myung Jin , Kim Ji Hoon , Kim Jae Wook , Ku Min Hee , Yang Jae Moon , Choi Eun Chang , Koh Yoon Woo , Lee Jeong Yeon
Published: July 2017

Cetuximab, an EGFR monocloanal antibody, is commonly known to be an effective treatment agent in head and neck squamous cell carcinoma (HNSCC). However, despite the clinical efficacy of cetuximab, a majority of patients with good initial response still suffer from side effects as the acquired resistance to cetuximab. To understand the mechanisms of acquired resistance to cetuximab, we developed a model by exposing a head and neck cancer cell line Cal27 to increasing concentrations of cetuximab and established cetuximab-resistant clones (CETr) derived from the cetuximab sensitive (CETp). We examined how the acquired resistance in the CETr influenced the signaling pathway compared to the CETp. We investigated the effect of lapatinib, a tyrosine kinase inhibitor inhibiting HER3, with or without cetuximab combination on CETr clones and in a xenograft mouse model. Cetuximab-resistant(CETr) clones showed robust overexpression on the HER family receptors HER3. CETr clones also expressed upregulated EGFR, HER2, and HER3 activation resulting in activation of PI3K/ATK and ERK signaling. We also showed that CETr clones exhibited increased EGFR/HER3 dimerization. Treatment of cetuximab and siHER3 RNA together reduced EGFR activation in CETr clones to re-sensitize cells against cetuximab and robustly decreased cell proliferation. Combined treatment of CETr clones with cetuximab and lapatinib led to potent anti-proliferative effects. Co-treatment with cetuximab and lapatinib blocked EGFR, HER2 and HER3 activities and inhibited downstream signaling pathways. Co-treatment resulted in suppression of cell growth more effectively than each drug alone and induced apoptotic cell death through mitochondrial ROS. Furthermore, Co-treatment with cetuximab and lapatinib also led to suppression of tumor growth in orthotopic xenograft mouse model of oral tongue cancer. Our results suggested the upregulation of HER3 as a mechanism underlying resistance to cetuximab in HNSCC, supporting further clinical treatment strategy for tumors displaying acquired resistance to cetuximab.

Citation Format: Yeon Ju Yang, Min Hee Cho, Yoo Jung Oh, Da Hee Kim, Jung Min Kim, Hyung Kwon Byeon, Myung Jin Ban, Ji Hoon Kim, Jae Wook Kim, Min Hee Ku, Jae Moon Yang, Eun Chang Choi, Yoon Woo Koh, Jeong Yeon Lee. Acquired resistance to cetuximab is mediated by HER3 activation in head and neck squamous cell carcinoma [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 4113. doi:10.1158/1538-7445.AM2017-4113
Abstract 4115: Combination of FTY720 and tamoxifen inhibits drug-resistant ovarian cancer cell proliferation
Authors: Kreitzburg Kelly Marie , Landen Charles N. , Gamblin Tracy , Arend Rebecca , Alvarez Ronald , Yoon Karina
Published: July 2017

Despite satisfactory initial responses to frontline therapies that combine surgical debulking with platinum based chemotherapy, virtually all women with advanced ovarian cancer relapse with drug resistant disease. There is a critical need to identify alternative, effective therapies.

Previously, we used patient derived xenograft (PDX) models of ovarian cancer in mice to identify the sphingosine1 phosphate (S1P) pathway as one of the pathways most affected by two agents frequently used to treat ovarian cancer, carboplatin and paclitaxel. The S1P pathway contributes to multiple biological processes recognized as essential for tumor development, and aberrations in sphingolipid metabolism have been directly correlated with advanced disease and with resistance to chemotherapy and radiation. Further, recent studies indicate that tamoxifen may counteract drug resistance mechanisms through modulation of sphingolipid metabolism, specifically through inhibition of the ceramide converting enyzmes acid ceramidase and glucosylceramide synthase. Therefore, we evaluated the efficacy of modulating S1P metabolism using the sphingosine analog FTY720 and tamoxifen as an approach to inhibit the proliferation of drug-resistant ovarian tumor cells.

We used alamarBlue cell proliferation assays to compare the anti-proliferative effect of FTY720 and tamoxifen with the effect of each drug as a single agent. FTY720 + tamoxifen synergistically decreased the cell viability of 3/3 ovarian cancer cell lines: estrogen receptor alpha (ERα) positive SKOV3.TR (taxane resistant), ERα negative A280.cp20 (platinum resistant) and HeyA8.MDR (taxane-platinum resistant). The combination also increased levels of apoptosis as reflected by Annexin V staining and cleaved caspase 3 levels. Further, administration of 5mg/kg i.p. FTY720 + 20mg/kg p.o. tamoxifen daily for 21 days to PDX-bearing mice demonstrated that FTY720 + tamoxifen suppressed tumor growth by ~60% compared to vehicle controls. Notably, immunohistochemical staining of tumors harvested from treated mice showed that the combination decreased expression of the proliferation marker Ki-67 and increased expression of apoptosis indicators ceramide and cleaved caspase 3 to a greater degree than in tumors exposed to either drug alone. We conclude that FTY720 + tamoxifen merit further investigation as potentially effective agents for the treatment of drug-resistant ovarian cancer.

Citation Format: Kelly Marie Kreitzburg, Charles N. Landen, Tracy Gamblin, Rebecca Arend, Ronald Alvarez, Karina Yoon. Combination of FTY720 and tamoxifen inhibits drug-resistant ovarian cancer cell proliferation [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 4115. doi:10.1158/1538-7445.AM2017-4115
Abstract 4131: ERRβ: Validating a novel target for triple negative breast cancer
Authors: Fernandez Aileen I. , Graham Garrett , Győrffy Balázs , Cavalli Luciane , Riggins Rebecca B.
Published: July 2017

Triple negative breast cancer (TNBC) - defined as estrogen receptor- (ER), progesterone receptor- (PR), and human epidermal growth factor receptor 2- (HER2) negative - is a highly aggressive form of breast cancer prevalent in African-American (AA) women. Because ER- and HER2-targeted therapies are ineffective in TNBC, current treatment strategies rely on cytotoxic chemotherapy. There is a tremendous need for new approaches that can identify effective therapies with less toxicity for this devastating form of breast cancer.

Nuclear receptors are highly druggable targets. Classical examples include ligand-regulated receptors like ER, but orphan nuclear receptors are also emerging as targets for cancer therapy. We recently published that increased mRNA expression of estrogen-related receptor beta (ERRβ, gene symbol ESRRB) correlates with better recurrence- and distant metastasis-free survival in women with TNBC, and that a small molecule agonist ligand for ERRβ (DY131, DY) has growth inhibitory and anti-mitotic activity in TNBC cell lines of multiple molecular subtypes. The goal of our current work is to validate ERRβ as a novel therapeutic target for TNBC in two distinct ways.

First, we sought to determine whether ERRβ is correlated with survival outcome specifically in African-American (AA) women. Analysis of The Cancer Genome Atlas (TCGA) Breast Cancer RNAseq data shows that low ERRβ mRNA expression is specifically associated with poor overall survival in AA women with TNBC. This association is not observed in AA women with ER- or HER2-positive disease. We further find that while ERRβ mRNA expression is decreased in tumor vs. normal breast tissue regardless of race, this decrease is more pronounced in AA women. Ongoing studies in an independent cohort of AA and white women will determine whether this is due, in part, to copy number changes at the ERRβ locus (chromosome 14q24.3).

Second, we sought to determine whether ERRβ expression could predict response to current treatment strategies commonly used in breast cancer, particularly TNBC. Using multiple combined datasets, we find that high ERRβ expression is associated with improved recurrence-free survival (RFS) in women with TNBC who received adjuvant or neoadjuvant therapy with anthracycline (e.g. doxorubicin, Adriamycin). No association between ERRβ and RFS is observed in patients treated with taxanes. Ongoing studies in TNBC cell lines seek to determine if activating ERRβ with its agonist ligand DY can enhance doxorubicin-mediated growth inhibition and cell death.

Citation Format: Aileen I. Fernandez, Garrett Graham, Balázs Győrffy, Luciane Cavalli, Rebecca B. Riggins. ERRβ: Validating a novel target for triple negative breast 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 4131. doi:10.1158/1538-7445.AM2017-4131
Abstract 4142: Regulation of tumor suppressor decorin by APE1 in head and neck squamous cell carcinoma
Authors: Wicker Christina A. , Scott Timothy L. , Suganya Rangaswamy , Arnold Susan M. , Brill Yolanda M. , Horbinski Craig M. , Napier Dana , Valentino Joseph , Kudrimoti Mahesh R. , Yu Guoqiang , Izumi Tadahide
Published: July 2017

Oral cancers have a high rate of recurrence, and a tendency to develop treatment resistance. From 2009 to 2013, Kentucky had a disproportionately higher incidence of invasive oral cancers and resultant higher mortality compared to the national average (SEER & NPCR, Kentucky Cancer Registry).

Apurinic/Apyrimidinic endonuclease (APE1) is a key protein in DNA repair, and an important transcriptional regulator. Gene array analysis in pMEFs expressing wild-type APE1 and extremely low levels of APE1 showed an eight-fold reduction of tumor suppressor decorin (DCN), with wild-type APE1.

Decorin is a known tumor suppressor and extracellular matrix protein, which can suppress tumor proliferation, migration and angiogenesis. Tumors with decreased decorin are associated with increased mortality.

These studies aim to elucidate APE1’s role in decorin regulation in oral cancer and identify biomarkers, which may aid in diagnosis, treatment, or predicting prognosis.

Immunohistochemistry studies of head and neck squamous cell carcinoma from Kentuckians were analyzed aided by Aperio’s high resolution scanning capabilities, and software. Analysis showed a significant decrease in decorin in both tumor and carcinoma in situ compared to benign tissue. Whereas, APE1 was significantly increased in tumors. Additionally there was a significant negative correlation between APE1 and decorin total protein in carcinoma in situ. This data supports that increased APE1 may deplete decorin. Superoxide Dismutase 3, which is important in detoxifying extracellular ROS, was also significantly decreased in tumor and in carcinoma in situ. This along with previous research showing increased ROS in the tumor microenvironment and APE1 activation by ROS may explain the origination of decorin suppression.

We hypothesize that the overexpression of APE1 in early stages of oral cancer leads to diminished decorin translation, which may drive cancer progression and increase mortality. Better understanding how APE1 influences tumor suppressors may eventually aid in development of therapeutics that would increase patient survival.

Citation Format: Christina A. Wicker, Timothy L. Scott, Rangaswamy Suganya, Susan M. Arnold, Yolanda M. Brill, Craig M. Horbinski, Dana Napier, Joseph Valentino, Mahesh R. Kudrimoti, Guoqiang Yu, Tadahide Izumi. Regulation of tumor suppressor decorin by APE1 in head and neck squamous cell carcinoma [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 4142. doi:10.1158/1538-7445.AM2017-4142
Abstract 4154: Resistance to BET inhibitors involves the β-catenin pathway in uveal melanoma
Authors: Ambrosini Grazia , Tycko Benjamin , Do Chaterine , Schwartz Gary K.
Published: July 2017

Uveal melanoma (UM) is an aggressive intraocular malignancy with high tendency to metastasize to the liver. Currently available drugs have shown limited clinical activity in patients with UM and there is an urgent need for new effective therapies. Recent findings from our laboratory demonstrated that UM cells are sensitive to BET inhibitors (BETi) through the induction of cell cycle arrest and apoptosis. However, despite the initial inhibitory effects, UM cells acquire resistance to this class of drugs following chronic drug exposure. In order to understand the mechanistic basis for BETi resistance in UM, we assessed genome-wide CpG methylation patterns in UM cell lines that had been rendered resistant to the clinical BET inhibitor PLX51107 (Plexxikon, Berkeley, CA) following chronic drug exposure. The comparison between BET inhibitor-resistant versus sensitive cell lines revealed differential methylation of 1700 genes, including several involved in Wnt/β-catenin signaling, as well as other signaling pathways. Immunoblotting analysis confirmed that β-catenin protein was induced and activated in the resistant cells, while depletion of β-catenin by siRNA re-sensitized the resistant cells to the BET inhibitor. We then explored several combinations of PLX51107 with drugs that block β-catenin transcriptional activity through inhibition of its phosphorylation by PAK4 or through the inhibition of binding partners like Cdk8 and CBP. All these combinations increased the activity of the BET inhibitor in both sensitive and resistant cells, and these effects were synergistic, with combination indexes (CI) <1. These observations support the evidence that acquired resistant to BET inhibitors is mediated, at least in part, by activation of the Wnt/β-catenin pathway, and inhibitors of this pathway may provide a means to overcome acquired BET inhibitor resistance in UM patients treated with this class of drugs.

Citation Format: Grazia Ambrosini, Benjamin Tycko, Chaterine Do, Gary K. Schwartz. Resistance to BET inhibitors involves the β-catenin pathway in uveal melanoma [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 4154. doi:10.1158/1538-7445.AM2017-4154
Abstract 4161: Increased expression of ABCB1 could be associated with osimertinib resistance in non-small cell lung cancer cell line PC9 cell
Authors: Nomizo Takashi , Ozasa Hiroaki , Tsuji Takahiro , Yasuda Yuto , Funazo Tomoko , Yoshida Hironori , Sakamori Yuichi , Nagai Hiroki , Kim Young Hak
Published: July 2017

Osimertinib, a third-generation EGFR Tyrosine kinase inhibitor, has shown promising activity in EGFR mutation positive non-small cell lung cancer (NSCLC) which harboring T790M mutation. The mechanisms of resistance to osimertinib have been still unclear. To investigate the mechanisms of acquired resistance to osimertinib, we established the osimertinib-resistant cell line (PC9/osimertinib) from the NSCLC cell lines PC9, and measured the expression levels of ATP-binding cassette (ABC) transporters using quantitative real-time polymerase chain reaction. Expression profiling of ABC transporters revealed that the levels of ABCB1 gene expression were significantly increased in the PC9/osimertinib cells compared with the parental cells, but not other ABC transporters. Knockdown of ABCB1 expression using short hairpin RNA enhanced osimertinib cytotoxicity in PC9/osimertinib cells. These data suggest that increased expression of ABCB1 may have an important role in the acquired resistance to osimertinib.

Citation Format: Takashi Nomizo, Hiroaki Ozasa, Takahiro Tsuji, Yuto Yasuda, Tomoko Funazo, Hironori Yoshida, Yuichi Sakamori, Hiroki Nagai, Young Hak Kim. Increased expression of ABCB1 could be associated with osimertinib resistance in non-small cell lung cancer cell line PC9 cell [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 4161. doi:10.1158/1538-7445.AM2017-4161
Abstract 4163: Blockade of the interleukin-1 signaling pathway overcomes erlotinib resistance in head and neck cancer cells
Authors: Simons Andrean L. , Stanam Aditya , Gibson-Corley Katherine N.
Published: July 2017

The EGFR tyrosine kinase inhibitor erlotinib has demonstrated poor clinical response rates for head and neck squamous cell carcinoma (HNSCC) to date and the majority of respondents acquire resistance to erlotinib relatively quickly. Our previous data has shown that erlotinib activated interleukin-1 (IL-1) expression and signaling in HNSCC cells in vitro. We therefore investigated if upregulation of IL-1 signaling is involved in erlotinib resistance in HNSCC cells. We compared gene expression profiles of erlotinib-resistant (ER) and the parental erlotinib-sensitive (ES) HNSCC cell lines and observed a deregulation of the IL-1 signaling pathway in ER versus ES-HNSCC cells using microarray enrichment analysis. Secretion of IL-1 alpha (IL-1α) and IL-1 beta (IL-1β) were not significantly different in ER-SQ20B and ER-CAL 27 cells compared to their respective ES-cells, however secretion of the IL-1 receptor antagonist (IL-1RA) was significantly reduced in ER-cells compared to ES-cells. Blockade of IL-1 signaling using a recombinant IL-1R antagonist (anakinra) was able to significantly suppress the growth of ER-SQ20B but not ES-SQ20B xenografts as a single agent and in combination with erlotinib. ER-SQ20B xenografts treated with anakinra with or without erlotinib were found to be less vascularized (as determined by CD31 staining) than ER-SQ20B xenografts treated with water or erlotinib. Altogether, blockade of the IL-1 pathway using anakinra overcame erlotinib resistance in HNSCC xenografts and may represent a novel strategy to overcome EGFR inhibitor resistance for the treatment of HNSCC patients.

Citation Format: Andrean L. Simons, Aditya Stanam, Katherine N. Gibson-Corley. Blockade of the interleukin-1 signaling pathway overcomes erlotinib resistance in head and neck 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 4163. doi:10.1158/1538-7445.AM2017-4163
Abstract 4165: SOX2 promotes lineage plasticity and antiandrogen resistance in TP53 and RB1 deficient prostate cancer
Authors: Mu Ping , Zhang Zeda , Benelli Matteo , Karthaus Wouter , Hoover Elizebeth , Chen Chi-Chao , Wongvipat John , Ku Sheng-Yu , Gao Dong , Cao Zhen , Shah Neel , Adams Elizabeth , Abida Wassim , Watson Philip , Prandi Davide , Huang Chun-Hao , Stanchina Elisa de , Lowe Scott , Ellis Leigh , Beltran Himisha , Rubin Mark , Goodrich David , Demichelis Francesca , Sawyers Charles L.
Published: July 2017

Some cancers evade targeted therapies through a mechanism known as lineage plasticity, whereby tumor cells acquire phenotypic characteristics of a cell lineage whose survival no longer depends on the drug target. Here we show, using in vitro and in vivo prostate cancer models, that these tumors can develop resistance to the antiandrogen drug enzalutamide by a phenotypic shift from androgen receptor (AR) dependent luminal epithelial cells to AR independent basal-like cells. This lineage plasticity is enabled by loss of TP53 and RB1 function, is mediated by increased expression of the reprogramming transcription factor SOX2 and can be reversed by restoring TP53 and RB1 function or by inhibiting SOX2 expression. Thus, mutations in tumor suppressor genes can create a state of increased cellular plasticity that, when challenged with antiandrogen therapy, promotes resistance through lineage switching.

Citation Format: Ping Mu, Zeda Zhang, Matteo Benelli, Wouter Karthaus, Elizebeth Hoover, Chi-Chao Chen, John Wongvipat, Sheng-Yu Ku, Dong Gao, Zhen Cao, Neel Shah, Elizabeth Adams, Wassim Abida, Philip Watson, Davide Prandi, Chun-Hao Huang, Elisa de Stanchina, Scott Lowe, Leigh Ellis, Himisha Beltran, Mark Rubin, David Goodrich, Francesca Demichelis, Charles L. Sawyers. SOX2 promotes lineage plasticity and antiandrogen resistance in TP53 and RB1 deficient prostate 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 4165. doi:10.1158/1538-7445.AM2017-4165
Abstract 4177: Anticancer agent Aminoflavone restores the expression of tumor suppressor miRNA 26a and inhibits putative stemness biomarker α6-integrin in Tamoxifen resistant cells
Authors: Campbell Petreena , Rowland Leah , Opoku-Agyeman Anna , Mavingire Nichole , Soto Ubaldo , Nagaraj Gayathri , Zhang Yonghong , Chen Sean (Xin) , Wang Charles , Brantley Eileen
Published: July 2017

Despite the efficacy of anti-estrogen agent Tamoxifen, commonly used to treat patients with estrogen receptor positive (ER+) tumors, up to 40% of patients experience recurrence. Breast tumor-initiating cells (TICs), or breast cancer stem cells, exhibit Tamoxifen resistance and contribute substantially to recurrence. We recently demonstrated that investigational anticancer agent Aminoflavone (AF) disrupts mammospheres (in vitro clusters of cells enriched with TICs) by thwarting the expression of α6-integrin. In the current study, we found AF potently inhibited Tamoxifen resistant (TamR) cell growth and blocked Tamoxifen-mediated stimulation of TamR cell proliferation using the Alamar Blue assay. qPCR analyses revealed α6-integrin expression was significantly elevated in ER+ breast cancer cell models of acquired and de novo Tamoxifen resistance relative to Tamoxifen sensitive cells. In particular, AF decreased the expression of both A and B variants of α6-integrin, the B variant being essential for TIC function. Western blotting revealed AF reduced total α6-integrin expression in TamR cells. Furthermore, we found that an anti-α6-integrin blocking antibody sensitized TamR cells to the active Tamoxifen metabolite, 4-hydroxy-Tamoxifen, and enhanced the efficacy of AF in these cells. AF also reduced the protein expression of p-Src, a downstream target of α6-integrin that is linked to Tamoxifen resistance and decreased breast cancer survival. In addition, miRNA sequencing of Tamoxifen sensitive and TamR mammospheres revealed differential expression of several miRNAs. Notably, miR-26a expression was down-regulated 2-fold in TamR mammospheres compared to Tamoxifen sensitive mammospheres and AF restored miR-26a expression 5-fold in TamR mammospheres. Using miRNA target prediction algorithms TargetScan and PicTar, we found miR-26a binding sites on the α6-integrin promoter. Taken together, our data suggest that AF re-expresses tumor suppressor miR-26a and inhibits the α6-integrin/Src signaling axis to reduce TIC capacity and counteract Tamoxifen resistance.

Citation Format: Petreena Campbell, Leah Rowland, Anna Opoku-Agyeman, Nichole Mavingire, Ubaldo Soto, Gayathri Nagaraj, Yonghong Zhang, Sean (Xin) Chen, Charles Wang, Eileen Brantley. Anticancer agent Aminoflavone restores the expression of tumor suppressor miRNA 26a and inhibits putative stemness biomarker α6-integrin in Tamoxifen resistant 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 4177. doi:10.1158/1538-7445.AM2017-4177
Abstract 418: Adaptive resistance to chemotherapy in triple-negative breast cancer revealed by single cell DNA and RNA sequencing
Authors: Kim Charissa , Gao Ruli , Sei Emi , Brandt Rachel , Crosetto Nicola , Foukakis Theodoros , Navin Nicholas
Published: July 2017

Triple-negative breast cancer (TNBC) is an aggressive subtype that displays extensive intratumor heterogeneity and frequently (46%) develops resistance to neoadjuvant chemotherapy (NAC). Currently, the genomic basis of chemoresistance remains poorly understood. An important question is whether resistance to chemotherapy is driven by the selection of rare pre-existing subclones with genomic mutations and transcriptional programs that confer resistance to chemotherapy (adaptive resistance) or by the spontaneous induction of new mutations and expression changes that confer a resistant phenotype (acquired resistance). To investigate this question we applied single cell DNA and RNA sequencing methods and deep-exome sequencing to longitudinal time-point samples collected from a cohort of 20 TNBC patients. Deep-exome sequencing of the cohort at three time points revealed a random death model, wherein multiple clones were targeted, as opposed to the selection of specific somatic mutations. In contrast, single cell copy number profiling of ~800 cells from 8 patients identified an adaptive resistance model, wherein minor subclones from the pre-treatment tumors were selected and expanded in response to NAC. Similarly, single cell RNA sequencing of ~8000 cells from 8 patients identified subclones with chemoresistant phenotypes that were selected in response to NAC, resulting in the expansion of the resistant tumor mass. These data suggest that chemoresistance evolves through the selection of copy number changes and expression changes in signaling pathways associated with chemoresistance, rather than point mutations. This adaptive resistance model has important translational implications in clinical diagnostics, by suggesting that resistant clones can be detected in TNBC patients prior to the administration of chemotherapy.

Citation Format: Charissa Kim, Ruli Gao, Emi Sei, Rachel Brandt, Nicola Crosetto, Theodoros Foukakis, Nicholas Navin. Adaptive resistance to chemotherapy in triple-negative breast cancer revealed by single cell DNA and RNA sequencing [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 418. doi:10.1158/1538-7445.AM2017-418