bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2063: The farnesyltransferase inhibitor tipifarnib causes dramatic tumor regression and increases survival in murine HrasG12V driven aggressive thyroid cancers: Consequent adaptive and acquired resistance mechanisms inform combination treatments with improved responses
Authors: Untch Brian R. , Anjos Vanessa Dos , Garcia-Rendueles Maria ER , Knauf Jeff A. , Ho Alan L. , Fagin James A.
Published: July 2017

Of the three RAS oncoproteins, only HRAS is delocalized and functionally inactivated by farnesyltransferase inhibition (FTI), an approach that has yet to be exploited clinically. We treated a murine model of poorly differentiated and anaplastic thyroid cancer (Tpo-cre/HrasG12V/p53flox/flox; Hras;p53) with the FTI tipifarnib, and observed sustained tumor regression and increased survival; however, tumors eventually recurred. Following HRAS delocalization by tipifarnib in vitro, ERK phosphorylation was only inhibited transiently in HRAS-mutant cell lines, which was associated with increased GTP loading of wild-type RAS proteins in the setting of RTK ligand stimulation. This adaptive reactivation of RAS-MAPK signaling was abrogated by selective RTK (i.e. EGFR, FGFR) inhibitors, or by MEK inhibitors. Importantly, tipifarnib combined with the MEK inhibitor AZD6244 led to improved responses in Hras;p53 mouse tumors, whereas combination with the EGFR/FGFR inhibitors erlotinib and ponatinib did not, suggesting heterogeneity of upstream inputs. In order to identify acquired resistance mechanisms, tumor-bearing Hras;p53 mice were treated with tipifarnib until resistance developed (6 months). Whole exome sequencing of resistant tumors identified a truncating NF1 mutation and an activating mutation in GNAS at high allelic frequency. Upon NF1 knockdown in the human HRAS- mutant cell line C643, tipifarnib failed to inhibit pERK in vitro and caused resistance to tipifarnib in xenografts. By contrast, activating GNAS mutations transduced into Hras;p53 mouse tumor cell lines produced tipifarnib-resistant xenografts that activated the GNAS-cAMP-CREB pathway and demonstrated signs of redifferentiation. These data show that pharmacological targeting of RAS in a genetically accurate, mouse model of a RAS-driven virulent cancer leads to objective major responses and improved survival. We identified adaptive and acquired resistance mechanisms, and show that combined treatment with selective MEK inhibitors are beneficial. These data should also inform a currently enrolling clinical trial of tipifarnib for HRAS-mutant malignancies.

Citation Format: Brian R. Untch, Vanessa Dos Anjos, Maria ER Garcia-Rendueles, Jeff A. Knauf, Alan L. Ho, James A. Fagin. The farnesyltransferase inhibitor tipifarnib causes dramatic tumor regression and increases survival in murine HrasG12V driven aggressive thyroid cancers: Consequent adaptive and acquired resistance mechanisms inform combination treatments with improved responses [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 2063. doi:10.1158/1538-7445.AM2017-2063
Abstract 2065: Targeting the crosstalk between MET and Notch signaling in Rhabdomyosarcoma
Authors: Rota Rossella , Cossetti Cristina , Pomella Silvia , Gualtieri Alberto , Carcarino Elena , Ponzetto Carola , Taulli Riccardo , Miele Lucio , Locatelli Franco
Published: July 2017

Rhabdomyosarcoma (RMS) in a pediatric soft tissue sarcoma expressing myogenic markers. RMS includes two histological subtypes, embryonal and alveolar, which differ clinically and molecularly. The majority of alveolar RMS expresses fusion oncoproteins such as PAX3/7-FOXO1. Fusion positive (FP) RMS are at high risk showing a dismal prognosis while fusion negative (FN) ones have a better outcome. The MET protooncogene is a target gene of PAX3-FOXO1 and is overexpressed in FP RMS. However, it is upregulated/overactivated in FN RMS as well. It concurs to disease pathogenesis and is a potential target of therapy. We have shown that MET is down-regulated by the myomiR cluster miR-1/206 that promotes myogenic-like differentiation and inhibits proliferation of RMS cells. Notch signaling is also deregulated in RMS and inhibition of either Notch1 in FN or Notch3 in both subtypes leads to tumor growth blockade. Some preliminary data from our lab indicate that the expression of miR-1/206 is induced in Notch3-silenced RMS cells. Therefore, we sought to investigate the crosstalk between MET and Notch signaling in RMS.

We detected a down-regulation of MET transcript and protein in Notch3 knocked down RMS cells. In turn, MET silencing reduced Notch1 and Notch3 activation together with the levels of Notch ligands, JAG1 and DLL1. In line with this, forced expression of an activated form of MET (Tpr) resulted in Notch1 over-activation and up-regulation in FN RMS cells. Notably, a FN cell line treated for long time (more than 6 months) with growing doses of EMD, a clinically relevant MET inhibitor, showed resistance to treatment, over-activation of MET, i.e., hyperphosphorylation, and Notch1 signaling hyperactivation. These preliminary results suggest that MET and Notch signaling could crosstalk in RMS and that their co-targeting could be used to overcome drug resistance to single agent therapy. To this end, combination treatments of MET inhibitors with clinically relevant gamma-secretase inhibitors are in course.

The work is supported by Associazione Italiana Ricerca sul Cancro project IG15312 to RR.

Citation Format: Rossella Rota, Cristina Cossetti, Silvia Pomella, Alberto Gualtieri, Elena Carcarino, Carola Ponzetto, Riccardo Taulli, Lucio Miele, Franco Locatelli. Targeting the crosstalk between MET and Notch signaling in Rhabdomyosarcoma [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 2065. doi:10.1158/1538-7445.AM2017-2065
Abstract 2070: HMGB1 governs p53 to autophagic degradation via its nucleus-to-cytoplasm transport
Authors: He Qiaojun , Luo Peihua , Yang Xiaochun , Weng Qinjie , Ding Ling , Yang Bo
Published: July 2017

P53 is under exquisitely fine regulation and acts as a transcription factor that regulates the expression of thousands of genes that control apoptosis, necroptosis, ferrotosis, cell cycle arrest, senescence, metabolism and fertility. Regulation of p53 turnover is essential not only for the response to chemotherapeutic drugs or radiation in cancer cell but also to keep p53 activity under control in a normal cell. Moreover, .p53 is found to be overactivated in various diseases including idiopathic pulmonary fibrosis (IPF), alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD). Promoting hyperactivated-p53 degradation can combat these diseases. However, the strategies that based on known proteasome-dependent degradation only can stabilize the expression level of p53 such as nutlins (inhibit the interaction between mdm2 and tumor suppressor p53). Autophagy-lysosomal degradation is the other pathway for controlling cellular protein stability. More and more researches have established that numerous proteins can be degraded through both proteasome and autophagy-lysosome pathways. However, very little is known to date about p53 turnover through autophagy-lysosome pathway. Here we discover that the activation of p53 autophagic degradation during an oral small molecule receptor tyrosine kinase inhibitor sunitinib in p53 wt cancer cells and normal cells. Mechanistically, the nucleus-to-cytoplasm shift is essential for the autophagic degradation of p53 induced by sunitinib, however, does not require p53 nuclear export signals. Indeed, p53 degradation is achieved by the nucleus-to-cytoplasm transport of its nuclear binding target HMGB1, shifting the distribution of p53 from the nucleus to the cytoplasm. Then cytoplasmic p53 directly interacts with the autophagy cargo receptor p62 to promote degradation. Importantly, inhibition of HMGB1 sensitizes cancer cell to sunitinib. Taken together, our study identified an alternative p53 protein turnover mechanism induced by sunitinib, thus not only elucidating the underlying mechanisms that limit sunitinib efficacy in cancer therapy but also opening an avenue for expanding the clinical indications of sunitinib.

Note: This abstract was not presented at the meeting.

Citation Format: Qiaojun He, Peihua Luo, Xiaochun Yang, Qinjie Weng, Ling Ding, Bo Yang. HMGB1 governs p53 to autophagic degradation via its nucleus-to-cytoplasm transport [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 2070. doi:10.1158/1538-7445.AM2017-2070
Abstract 2073: A systematic investigation of the effect of scheduling of targeted combination therapies on response and dynamics of relapse in triple negative breast cancer cells
Authors: Patwardhan Gauri A. , Wali Vikram B. , Pusztai Lajos , Hatzis Christos
Published: July 2017

Cancer treatment typically involves administration of combination of targeted therapies, but initial response is often followed by disease relapse. The efficacy of a treatment regimen depends on the complex interplay between cancer growth dynamics, drug specificity and kinetics, treatment dose and its scheduling. In standard high-throughput drug screening assays, cells are treated with a single drug cocktail bolus and cell viability is assessed after 2-3 days, thus not considering treatment interactions and long-term effects. Recently we have reported a promising synergistic combination of crizotinib (ALK/MET inhibitor) and ABT-263 (BCL2/BCL-XL inhibitor) against triple negative breast cancer cells. To understand the effect of the sequence and combination doses of crizotnib and ABT-263, we designed a comprehensive experimental plan that involved a total of 567 treatment regimens by varying treatment duration with the first drug (1, 2, or 3 days), followed by drug withdrawal and recovery period (2, 5 or 10 days) and then by a second cycle of treatment and recovery periods over a 26-day period. Cell viability was assessed by the CellTiter-Glo luminescence assay. Interestingly, ABT-263 alone induced higher cytotoxicity than an equivalent dose of crizotinib, but the remaining viable cells recovered much faster after ABT-263 withdrawal than cells after crizotinib withdrawal. Furthermore, cells exposed to higher doses of ABT-263 eventually become less sensitive to crizotinib. Among sequential regimens, crizotinib followed by ABT-263 was significantly more effective than ABT-263 followed by crizotinib, and combinations that included lower doses of ABT-263 were most effective. Taken together, our results show a significant interaction between the two targeted therapies, and suggest that it may be possible to select treatment scheduling that can delay drug resistance and tumor relapse in vivo.

Note: This abstract was not presented at the meeting.

Citation Format: Gauri A. Patwardhan, Vikram B. Wali, Lajos Pusztai, Christos Hatzis. A systematic investigation of the effect of scheduling of targeted combination therapies on response and dynamics of relapse in triple negative breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2073. doi:10.1158/1538-7445.AM2017-2073
Abstract 2078: CK-101 (RX518), a mutant-selective inhibitor of EGFR that overcomes T790M-mediated resistance in NSCLC
Authors: Qian Xiangping , Zhu Yong-Liang , Cullen Edward , Niecestro Robert M. , Oliviero James F.
Published: July 2017

Patients with non-small cell lung cancer (NSCLC) with activating epidermal growth factor receptor (EGFR) mutations initially respond to small molecule inhibitors of the EGFR tyrosine kinase such as gefitinib and erlotinib. However, secondary mutations in the kinase domain lead to acquired resistance to these inhibitors and limited clinical efficacy, with the EGFR T790M mutation being the most common mechanism of acquired resistance in more than half the patients that experience disease progression. CK-101 (also known as RX518) is a novel, irreversible, orally administered EGFR kinase inhibitor that specifically targets the mutant forms of EGFR, including T790M, while exhibiting minimal activity toward the wild-type (WT) EGFR. WT EGFR inhibition is believed to drive the commonly observed side effects of skin rash and diarrhea. The 50% inhibitory concentrations (IC50s) of CK-101 and 2 reference compounds, afatinib and AZD-9291, were determined in cell proliferation assays in human cancer cell lines in vitro after incubation for 72 hours. Xenograft studies were conducted in BALB/c nude mice or SCID/Beige mice using once daily oral administration of CK-101 or afatinib for 14 or 21 days. CK-101 selectively inhibited cell proliferation of cell lines expressing both the activating (e.g. HCC827, IC50 <0.015 µM) and resistance mutations (NCI-H1975, IC50 <0.005 µM), but was much less potent at inhibiting proliferation of cell lines expressing the WT form of the receptor (e.g. A431, IC50 >0.5 µM; i.e., CK-101 was over 100 fold less potent against A431 than against NCI-H1975). Single agent CK-101 significantly inhibited tumor growth in EGFR-mutated NSCLC tumor xenograft models, with no activity in a WT EGFR tumor xenograft model. In a xenograft study of PC-9 cells (exon 19 deletion) in SCID/Beige mice, CK-101 inhibited tumor growth by up to 90% (p <0.001). In a xenograft study of NCI-H1975 cells (L858R/T790M double mutant) in BALB/c nude mice, CK-101 inhibited tumor growth by up to 95% (p <0.001). The pre-clinical findings from this work strongly supported the clinical development of CK-101, and a first-in-human study of CK-101 was initiated in September 2016.

Citation Format: Xiangping Qian, Yong-Liang Zhu, Edward Cullen, Robert M. Niecestro, James F. Oliviero. CK-101 (RX518), a mutant-selective inhibitor of EGFR that overcomes T790M-mediated resistance in NSCLC [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 2078. doi:10.1158/1538-7445.AM2017-2078
Abstract 208: Proteomic measurements of protein abundance and phosphorylation identify novel kinase-substrate relationships in ovarian cancer
Authors: McDermott Jason E. , Liu Tao , Payne Samuel , Petyuk Vladislav , Zhang Hui , Zhang Zhen , Chan Daniel , Smith Richard , Rodland Karin ,   Clinical Proteomic Tumor Analysis Consortium
Published: July 2017

As part of the Clinical Proteomic Tumor Analysis Consortium (CPTAC), we have recently published the first large-scale proteomic and phosphoproteomic analysis of high-grade serous ovarian tumors. We observed that phosphorylation status was an excellent indicator of pathway activity and could discriminate between patient survival times. This dataset covers tumor samples from 69 patients with deep phosphoproteomic depth (>20,000 phosphopeptides confidently identified). Our continuing analysis of this dataset, reported here, has revealed that the correlation between kinase protein abundance and abundance of phosphorylated target peptides is very low, indicating that kinase abundance is not a good proxy for phosphorylation status overall. However, highly correlated kinase-substrate pairs are significantly more likely to be true relationships (from existing knowledge), demonstrating that this method could be used to predict novel kinase targets in some cases. Using this approach we predicted novel kinase-target relationships and constructed a kinase activity network of ovarian cancer. To better analyze cancer-relevant pathway activity we developed a novel approach that characterizes correlation, differential abundance, and statistical interactions between components to analyze multiple omics types in the context of signaling and functional pathways. We used this approach, called the Layered Enrichment Analysis of Pathways (LEAP), to identify active pathways in molecular subtypes of ovarian cancer, contrasting observations in patients stratified for short versus long overall survival. This analysis resulted in a pre-treatment protein-based signature that is significantly predictive of overall survival. Our results show that integration of multiple omics types has the ability to inform our understanding of novel kinase-substrate interactions, and potentially identify novel interactions associated with patient survival.

Note: This abstract was not presented at the meeting.

Citation Format: Jason E. McDermott, Tao Liu, Samuel Payne, Vladislav Petyuk, Hui Zhang, Zhen Zhang, Daniel Chan, Richard Smith, Karin Rodland, Clinical Proteomic Tumor Analysis Consortium. Proteomic measurements of protein abundance and phosphorylation identify novel kinase-substrate relationships in ovarian 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 208. doi:10.1158/1538-7445.AM2017-208
Abstract 2080: Polycomb-mediated disruption of an AR-feedback loop drives castration-resistant prostate cancer
Authors: Fong Ka-Wing , Zhao Jonathan , Kim Jung , Li Shangze , Yang Angela , Song Bing , Rittié Laure , Hu Ming , Yang Ximing , Perbal Bernard , Yu Jindan
Published: July 2017

Androgen receptor (AR) is an androgen-stimulated transcription factor that critically promotes prostate cancer development and progression. In addition to its conventional role in transcriptional activation, AR also acts as a transcriptional repressor to directly inhibit target gene expression. Through meta-analysis of androgen-regulated expression microarray data, we nominated CCN3/NOV, a CCN family protein, as one of the top AR-repressed genes in prostate cancer, implicating that CCN3 may play a tumor suppressive role in prostate cancer development. Therefore, we sought to investigate the molecular functions of CCN3 and its roles in prostate cancer progression especially in castration-resistant prostate cancer (CRPC). We first showed that CCN3 protein physically interacts with AR. The CCN3 interaction domain was mapped in the N-terminal domain of AR which is also present in constitutively active AR variants. Using immunofluorescence microscopy as well as subcellular fractionation technique, we demonstrated that CCN3 sequesters AR or AR variants into the cytoplasm to inhibit AR nuclear translocation, which in turn suppresses AR chromatin targeting and transcriptional activation. However, this negative feedback loop between AR and AR-repressed gene CCN3is disrupted in CRPC through CCN3 persistent epigenetic silencing by the Polycomb group protein EZH2, rendering AR transcriptional activation and CRPC progression. Taking advantage of this repressive mechanism, we restored CCN3 in CRPC cell model, either through ectopic overexpression or treatment with EZH2 inhibitor, which results in strong suppression of CRPC cell proliferation and anchorage-independent cell growth. Consistently, application of EZH2 inhibitor remarkably reduced tumor size in a castrated mice model. Taken together, our data highlight CCN3 as a novel regulator of AR signaling and support the promise of EZH2-targeting agents in treating CRPC.

Citation Format: Ka-Wing Fong, Jonathan Zhao, Jung Kim, Shangze Li, Angela Yang, Bing Song, Laure Rittié, Ming Hu, Ximing Yang, Bernard Perbal, Jindan Yu. Polycomb-mediated disruption of an AR-feedback loop drives castration-resistant 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 2080. doi:10.1158/1538-7445.AM2017-2080
Abstract 2090: Targeting estrogen receptor negative breast cancer cells using diarylthiourea analogs of SHetA2
Authors: Zou Hongye , Ginn Emily , Francis Sabah M. , Liu Shengquan , Louie Maggie
Published: July 2017

Breast cancer is one of the most common cancers that occur in women in the United States. Depending on the expression of estrogen receptor α (ERα), breast cancer can be classified as ER-positive or negative. ER-negative (ER-) breast cancers are often more aggressive and have poorer prognosis compared with the ER-positive (ER+) subtype. Consequently, there is a great need to develop more targeted therapeutic options for ER- breast cancer. One such compound is SHetA2, a flexible heteroarotinoid (flex-hets) that has been shown to inhibit growth of multiple cancer types including breast cancer. However, the clinical utility of SHetA2 is limited by its high lipophilicity (LogP). The goal of this study is to screen eleven 2nd generation analogs of SHetA2 with lower LogP values— SL1-22, 24, 27, 29, 30, 32, 36, 37, 38, 39, and 40— on different breast cancer cell lines to identify potential lead compounds that show the highest anti-growth activities against ER- breast cancer cells and further delineate the mechanism by which these compounds affect breast cancer cell growth. Results from this study demonstrate that SL1-38 [1-(3-chloro-4-methylphenyl)-3-(4-nitrophenyl)thiourea] and SL1-39 [1-(4-chloro-3-methylphenyl)-3-(4-nitrophenyl)thiourea], inhibit ER-negative breast cancer cells (MDA-MB-231, MDA-MB-453 and MDA-MB-468) effectively at micromolar concentrations. In order to understand the mechanisms of action, we evaluated the effects of SL1-38 and 39 on the expression of key cell cycle regulators. Our results show that these two analogs down-regulate the expression of cyclin A, cyclin B, cyclin D1, cyclin E and cdk2 and block S-phase progression. Taken together, these preliminary results suggest that SL1-38 and 39 may be further developed as anti-cancer agents for treating ER-negative breast cancer.

Citation Format: Hongye Zou, Emily Ginn, Sabah M. Francis, Shengquan Liu, Maggie Louie. Targeting estrogen receptor negative breast cancer cells using diarylthiourea analogs of SHetA2 [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 2090. doi:10.1158/1538-7445.AM2017-2090
Abstract 2095: E7090, a novel and selective FGFR inhibitor, for the treatment of cholangiocarcinoma cells harboring FGFR2-fusion genes
Authors: Miyano Saori W. , Arai Yasuhito , Matsui Junji , Shibata Tatsuhiro
Published: July 2017

Genetic abnormalities (gene fusion, mutation and amplification) of fibroblast growth factor receptor (FGFR) family members are known to cause constitutive activation of their signaling pathways, which play an important role in proliferation, survival and migration of cancer cells, as well as tumor angiogenesis. Several recent studies have identified that FGFR2 gene fusions were found in about 10% of intrahepatic cholangiocarcinoma and acted as oncogenes. E7090, an orally available FGFR1, 2 and 3 inhibitor, whose chemical-structure and basic kinase inhibitory profile have been disclosed at AACR2015, is currently under a first-in-human study (NCT02275910). The antitumor activity of E7090 against NIH3T3 and human cholangiocarcinoma cells harboring FGFR2-fusion genes was investigated. NIH3T3 cells stably infected of five FGFR2-fusion genes (FGFR2-AHCYL1, FGFR2-BICC1 type1, FGFR2-BICC1 type2, FGFR2-TXLNA, or FGFR2-KCTD1), all of which were discovered in human intrahepatic cholangiocarcinoma patients, were successfully established and exhibited anchorage-independent cell growth in soft agar assay. E7090 revealed an inhibitory activity on soft agar colony formation of these cells with IC50 values of 0.9 to 17.3 nmol/L in a dose dependent manner. E7090 also reduced activation of downstream pathways of FGFR signaling (MAPK and STAT3) in these cells. Subcutaneous transplantation of FGFR2-BICC1 type2, FGFR2-TXLNA, or FGFR2-KCTD1 expressing cells into immune-deficient mice produced tumor growth, and then oral administration of E7090 at 12.5, 25 and 50 mg/kg showed significant tumor growth inhibition. Finally, antitumor activity of E7090 was examined in a patient derived xenograft (PDX) model of human cholangiocarcinoma harboring FGFR2-BICC1 fusion gene. E7090 also showed dose-dependent antitumor activity and more than 50% of tumor regression was achieved at a dose of 50 mg/kg. In conclusion, E7090 showed potent antitumor activity against FGFR2-fusion genes found in intrahepatic cholangiocarcinoma both in vitro and in vivo models, suggesting that E7090 may provide therapeutic opportunities for cholangiocarcinoma harboring FGFR2-fusion genes.

Citation Format: Saori W. Miyano, Yasuhito Arai, Junji Matsui, Tatsuhiro Shibata. E7090, a novel and selective FGFR inhibitor, for the treatment of cholangiocarcinoma cells harboring FGFR2-fusion genes [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 2095. doi:10.1158/1538-7445.AM2017-2095
Abstract 21: Regulation of proliferation and invasion through the inhibition of IGF signaling pathway on Epstein-Barr virus associated gastric cancer
Authors: Jeong Inhye , Lee Hoi Young , Roh Jae Kyung , Kim Tae Soo , Lee Suk Kyeong , Jang Woo-Ick , Chung Hyun Cheol , Rha Sun Young
Published: July 2017

Epstein-Barr virus associated gastric cancer (EBVaGC) is one subtype of four molecular classifications by TCGA group. Specifically, EBV related viral RNAs, microRNAs and proteins regulate cancer progression phenomena like aggressiveness, motility, invasion and metastasis. Nonetheless, understanding the mechanisms of viral growth dependency beyond malignant EBV transformation are still deficient. Finding the EBV dependent pathway with significant biological role and the clinically appropriated drug is needed for EBVaGC in this regard. We investigated new therapeutic target and its role of regulating in proliferation and invasion using EBVaGC cell line model. First, we determined proliferation both of AGS and EBV infected AGS (AGS-EBV) cell lines during 7 days by proliferation assay. For the test of BI836845 (IGF ligand neutralizing antibody, Boehringer Ingelheim, German) efficacy, CCK-8 assay was performed. mRNA expression levels of IGF-1R, IGF-1, IGFBP-3 and IGFBP-6 which is the key regulator of IGF-signaling were measured by RT-PCR. Also, protein expression levels of IGF associated and downstream factors were confirmed by Western blotting. Lastly, invasiveness of cells was detected by invasion assay. As a result, AGS-EBV showed the slower proliferation rate compared to AGS, but the sensitivity to BI836845 was significantly increased in a dose-dependent manner (p<0.001). Interestingly, baseline IGFBP-3 mRNA expression of was enhanced in AGS-EBV compared with AGS. In addition, BI836845 treated group showed up-regulated IGFBP-3 mRNA level in AGS and down-regulated IGFBP-3 mRNA level in AGS-EBV. When BI836845 treated to AGS-EBV, phospho-Akt level was highly inhibited. Moreover, invasiveness of AGS-EBV was elevated about 2 fold more than AGS. Treatment of BI836845 in AGS-EBV represented significant decrease the invasiveness (p=0.08). In conclusion, AGS-EBV seems to modulate their proliferation and invasion through the IGF signaling pathway. Inhibition of IGF signaling pathway would be the potential therapeutic strategy for EBV associated gastric cancer.

Citation Format: Inhye Jeong, Hoi Young Lee, Jae Kyung Roh, Tae Soo Kim, Suk Kyeong Lee, Woo-Ick Jang, Hyun Cheol Chung, Sun Young Rha. Regulation of proliferation and invasion through the inhibition of IGF signaling pathway on Epstein-Barr virus associated gastric 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 21. doi:10.1158/1538-7445.AM2017-21
Abstract 2106: In-depth profiling of the energy depletion-mediated cancer cytotoxicity by passively delivered zinc complexes via PARP1 activation
Authors: Chung Jinhyuk F. , Park Tae Jung , Norihisa Yoko
Published: July 2017

Dysfunctional apoptotic function from impaired p53 tumor suppressor activity leads to poorer prognosis in cancer patients by compromising drug sensitivity and promoting drug resistance development. Programmed necrosis following energy crisis is a theoretically proposed cytotoxic mechanism for circumventing this problem. Herein we demonstrate that a biodegradable zinc complex is capable of triggering the programmed necrosis via activation of PARP1/PARG/MPTP, which consistently resulted in p53-independent broad spectrum cytotoxicity in vitro across all 20 cancer cell lines tested including many with reported drug resistance phenotypes. Additionally, we investigated its possible interaction with agents that influence p53 for possible antagonism/synergism. Supporting in vivo evidence in both animal models and clinical case studies involving terminal chemo-resistant gastric cancer patients upon oral administration (30 mg Zn/day) are presented. These results implicate macromolecular biodegradable zinc complexes as promising antitumor agents of simple compositions for overcoming the current hurdles in clinics, and warrant further clinical investigations. We plan to advance the studies through non-invasive smart devices reporting real-time blood glucose, blood pressure, microperfusion, and other hemodynamic parameters.

Citation Format: Jinhyuk F. Chung, Tae Jung Park, Yoko Norihisa. In-depth profiling of the energy depletion-mediated cancer cytotoxicity by passively delivered zinc complexes via PARP1 activation [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 2106. doi:10.1158/1538-7445.AM2017-2106
Abstract 2108: Imatinib-induced downregulation of Skp2 inhibits cell growth in human squamous cell carcinoma
Authors: Jeong Hyo Jin
Published: July 2017

It is apparent that Skp2(S-phase kinase associated protein) plays a crucial role in tumorigenesis of various human cancers. Imatinib, inhibitor of BCR-ABL tyrosine kinase, KIT and PDGF receptor, has been approved for the treatment and investigation of chronic myeloid leukemia, gastrointestinal stromal tumors and additional various solid tumors. But An area of skin cancer has not been yet investigated. The aim of this study was to explore the role of the Skp2 in Imatinib antitumor effect on human skin cancer. To explore Imatinib effect on growth of A431 cells (squamous cell carcinoma / skin cancer) we conducted CCK8 assay and Flow cytometry. Western blot assay was performed for determining the functions and molecular mechanism of Imatinib in A431 cells. we found that Imatinib significantly inhibited cell growth and induced cell cycle arrest at G0/G1 phase. Furthermore, we observed that depletion of Skp2 triggered cell cycle arrest and colony formation inhibition by Imatinib. Mechanistically we identified that Imatinib markedly downregulated Skp2 protein expression and subsequently upregulated p21 expression via increased protein stability. In conclusion, Imatinib exerts its antitumor activity via inhibition of Skp2 - p21 axis and these findings suggest that targeting Skp2 by Imatinib could be promising therapeutic approach for Squamous cell carcinoma therapy.

Note: This abstract was not presented at the meeting.

Citation Format: Hyo Jin Jeong. Imatinib-induced downregulation of Skp2 inhibits cell growth in human 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 2108. doi:10.1158/1538-7445.AM2017-2108
Abstract 2111: Ciclopirox inhibits tumor cell motility by suppressing protein expression of small GTPases and phosphorylation of paxillin
Authors: Huang Shile , Shen Tao
Published: July 2017

Ciclopirox olamine (CPX), an off-patent antifungal drug, is used for the treatment of superficial mycoses. Recent studies have demonstrated that CPX also possesses potent anticancer activity by inhibiting cell proliferation and inducing cell death in tumor cells. However, it is unknown whether CPX inhibits cell motility. In the present study, we found that CPX potently inhibited cell motility in a concentration-dependent manner in rhabdomyosarcoma (Rh30 and RD) cells, which was independent of the reduction of cell viability. As small GTPases (RhoA, Cdc42, and Rac1) and focal adhesion proteins (paxillin) play critical roles in the regulation of cell motility, we further studied whether CPX affects these proteins. Our Western blot analysis revealed that CPX did inhibit cellular protein expression of RhoA, Cdc42 and Rac1. However, by RT-PCR analysis, CPX did not alter the mRNA levels of the small GTPases. As microRNAs (miRNAs) can regulate protein expression at transcriptional and post-transcriptional levels, we investigated the effect of CPX on the expression of miRNAs. Our miRNA PCR array revealed that treatment with 10 μM of CPX for 24 hours upregulated the expression of 27 miRNAs by 2.04-6.10 fold, and downregulated the expression of 7 miRNAs by 2.00-7.89 fold in Rh30 cells. Further research is ongoing to identify whether these up/downregulated miRNAs are linked to the reduced expression of small GTPases and potentially more proteins. In addition, we found that CPX inhibited the phosphorylation of paxillin, despite no effect on the total cellular protein expression. The results suggest that CPX inhibits tumor cell motility at least by suppressing the protein expression of small GTPases and the phosphorylation of paxillin. Supported by the Feist-Weiller Cancer Center, LSU Health Sciences Center, Shreveport, LA.

Citation Format: Shile Huang, Tao Shen. Ciclopirox inhibits tumor cell motility by suppressing protein expression of small GTPases and phosphorylation of paxillin [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 2111. doi:10.1158/1538-7445.AM2017-2111
Abstract 2113: Mechanism of action of pixantrone in non-Hodgkin's lymphoma cells
Authors: Ng Serina , Muñoz Ruben , Hoff Daniel Von , Han Haiyong
Published: July 2017

Background: Pixantrone (PIX), an anthracenedione analog, has shown promising results with reduced cardiotoxicity as compared to structurally similar mitoxantrone and doxorubicin (DOX) in early phase clinical trials in patients with non-Hodgkin’s lymphoma (NHL). The exact mechanisms of action on how PIX induce cell death by targeting DNA replication through intercalating DNA and/or inhibiting Topoisomerase II has not been clearly illustrated.

Methods: A short-term cell proliferation assay (3 days treatment) and a long-term clonogenic assay (cells were treated with the drugs for 24 hours and then allowed to grow into colonies for 10-14 days) were used to assess and compare the effects of PIX and DOX on cell growth in three NHL cell lines, OCI-Ly8, Z138, and Raji. Immunofluorescent assays using γH2AX antibodies, and DAPI staining were used to examine the effect of PIX and DOX on the formation of double-strand breaks and micronuclei.

Results: In the short-term cell proliferation assay, PIX was not as potent as DOX (IC50 values ranging from 22 nM to 2737 nM for PIX and 2.8 nM to 67 nM for DOX). The two drugs were significantly more potent in the long-term clonogenic assay with IC50 values in low nanomolar range (5.1 nM to 82.8 nM) and the difference between PIX and DOX was much smaller. Cells treated with PIX displayed less increases in DNA double-strand breaks compared to those of DOX as quantified by the number of γH2AX positive foci formed in the cells. Furthermore, PIX treatment significantly increased the formation of micronuclei in a drug concentration and time dependent manner.

Conclusions: The findings from the current study indicate that PIX induces DNA damages that impair the chromosomal segregation but do not significantly trigger double-strand breakage checkpoint response. Overall, our results suggest that PIX may exert its antitumor activity via mechanisms that are different from those of DOX.

Citation Format: Serina Ng, Ruben Muñoz, Daniel Von Hoff, Haiyong Han. Mechanism of action of pixantrone in non-Hodgkin's lymphoma 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 2113. doi:10.1158/1538-7445.AM2017-2113
Abstract 2118: The food additive agent potassium bromate prevents growth and aggressive phenotypes by targeting multiple molecular signatures in breast cancer cells
Authors: Ghosh Priyanka , Maity Gargi , Banerjee Snigdha , Banerjee Sushanta
Published: July 2017

Potassium bromate (KBrO3) is by-product of ozone that has found multifunctional purpose in modern society. It is used as disinfectant in drinking water, a bleaching agent to improve flour, a component of cold-wave hair lotion and an ingredient in the production of fish paste and fermented beverages. Potassium bromide has also been used in America for bread-baking as a safe food additive since 1914. Despite the commercial value of this chemical, some studies suggest that KBrO3 could be a carcinogen. During the bread-baking process, Potassium bromate is normally converted into a stable and inert compound, potassium bromide (KBr). However, due to incomplete reduction, the residual KBrO3 remains in the bread, which eventually acts as a potential carcinogen to humans. Interestingly, our studies, in breast cancer cells, found contrasting results. We found that KBrO3 delays growth of ER-α positive luminal type breast cancer cells and triple-negative breast cancer cells (TNBC) via inducing apoptosis in a dose-dependent manner. KBrO3-induced apoptosis is mediated via targeting BCL-2/Bax and Caspase-3 signaling pathway. Moreover, aggressive phenotypes such as migration, invasion and sphere-forming ability of breast cancer cells are significantly impaired by KBrO3-treatment via targeting multiple molecular signatures in breast cancer cells. The growth inhibition effect of KBrO3 is also documented in a tumor xenograft model. Collectively, our findings provide a rationale for the basic and pre-clinical evaluation of the role of KBrO3 in breast cancer progression and therapy.

Citation Format: Priyanka Ghosh, Gargi Maity, Snigdha Banerjee, Sushanta Banerjee. The food additive agent potassium bromate prevents growth and aggressive phenotypes by targeting multiple molecular signatures in breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2118. doi:10.1158/1538-7445.AM2017-2118
Abstract 2124: Differentiation of myeloid and multiple myeloma cell lines by inecalcitol involves a marked decrease in CD44 and CD49d cell surface labeling
Authors: Benjamin Susan , Planquette Cecile , Delansorne Remi
Published: July 2017

Inecalcitol is a vitamin D receptor (VDR) agonist characterized by a high antiproliferative activity on various cancer cell lines (Okamoto et al., 2012; Ma et al., 2013) and a low calcemic potential as demonstrated by the high maximal tolerated oral daily dose of 4 mg in human patients (Medioni et al., 2014). On myeloid cells, inhibition of proliferation by vitamin D derivatives is paralleled by induction of differentiation into a monocyte/macrophage phenotype, mostly described as gain of functions (increase in lysozyme activity, phagocytosis and cell motility; Abe et al., 1981) and of the cell surface CD11b and CD14 biomarkers. The stimulation of the secretion of cathelicidin, a natural human antimicrobial peptide, is another specific activity of vitamin D and its derivatives (Wang et al., 2004).

During a screening of 48 CD biomarkers on 4 human myeloid cell lines (HL-60, U-937, MOLM-13 and THP1) and 4 human multiple myeloma cell lines (MM.1R, MM.1S, L-363 and RPMI-8226) treated for 72 hours at 10 nM, we recently discovered that inecalcitol reproducibly induces CD38 expression (Benjamin et al., 2016), another gain of function. We now report the decrease in CD44 and CD49d cell surface labeling in all 8 cell lines (except CD44 in L-363 cells). This loss of functions reached -60% to -70% in MOLM-13 and HL-60 cells. We have then determined the EC50 (mean ± SEM; n = 3 or 4) of inecalcitol for several differentiation parameters on HL-60 cells. The most sensitive gains or loss of functions were the secretion of cathelicidin (0.2 ± 0.1 nM), the induction of CD38 (0.3 ± 0.1 nM) and the decrease in CD44 (0.8 ± 0.4 nM). Inhibition of proliferation (1.9 ± 0.8 nM) was exactly parallel to induction of CD11b (1.8 ± 0.8 nM). Decrease in CD49d (6.6 ± 1.1 nM) and increase in CD14 (8.0 ± 0.5 nM) occurred as final markers of differentiation by inecalcitol.

CD44 is the receptor for hyaluronic acid; it is found on the surface of acute myeloid leukemia stem cells and suspected to favor the spread and relapse of the disease. CD49d is the integrin α4-subunit involved in the interactions of tumor cells with their microenvironment resulting in their “hiding” and survival. Therefore, decreasing both CD44 and CD49d represents newly identified potential beneficial pro-differentiation effects of inecalcitol.

Citation Format: Susan Benjamin, Cecile Planquette, Remi Delansorne. Differentiation of myeloid and multiple myeloma cell lines by inecalcitol involves a marked decrease in CD44 and CD49d cell surface labeling [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 2124. doi:10.1158/1538-7445.AM2017-2124
Abstract 2126: CA102N, a conjugate of hyaluronic acid (ha) and Nimuselide derivative (H-Nim) interferes with PI3K/Akt/mTOR signaling pathway in colorectal cancer (CRC) cells and inhibits tumor growth in vivo
Authors: Tchaparian Eskouhie H. , Lin Louis
Published: July 2017

Aberrant PI3K/Akt/mTOR signaling pathway is common in several human cancers, including CRC. The pathway regulates many major cellular processes and promotes tumorigenesis and inhibition of apoptosis. Targeting the PI3K/Akt/mTOR network could be important in resistance mechanisms in cancer. CA102N, is a conjugate of Hyaluronic Acid (HA) and H-Nim, a nimuselide (COX-2 inhibitor) derivative, currently under investigation for preclinical development in CRC. Studies have suggested that the anti-proliferative effects of COX-2 inhibitors could be attributed to modulation of the PI3K/AKT signaling pathway; therefore, in this study we aimed to examine the overall molecular mechanism of the antitumor activity of CA102N and evaluate its impact on the PI3K pathway proteins. Cell based studies indicated that in addition to cell cycle arrest; the antitumor activity of CA102N is also related to apoptosis. Administration of CA102N to nude mice bearing established HT29 subcutaneous tumor xenografts caused significant tumor growth inhibition with no signs of systemic toxicity. Immunohistochemical analyses of xenograft tumors demonstrated inhibition of VEGF and CD31, suggesting a role for CA102N in angiogenesis. Disruption of angiogenesis and apoptosis was correlated with a decrease in VEGF and the antiapoptotic protein BCL-2. Suppression of PI3K downstream signaling was a key observation in HT29 cells in vitro and in xenograft tumors treated with CA102N. As compared to untreated vehicle control, a significant decrease in phosphorylation of AKT, mTOR, p70S6K, PRAS40, 4EBP1 and FOXO1 was detected by Western blot analyses. The reduction observed may be caused by both specific protein dephosphorylation/deactivation and by ubiquitin-mediated proteasomal degradation of pathway proteins. These results suggest that the antitumor activity of CA102N may be at least partly related to the modulation of the PI3K/Akt pathway proteins. CA102N represents a promising anticancer agent with minimal toxicity, the insights provided into the mechanisms of its anticancer activity may be the basis for advancing this candidate into clinic.

Citation Format: Eskouhie H. Tchaparian, Louis Lin. CA102N, a conjugate of hyaluronic acid (ha) and Nimuselide derivative (H-Nim) interferes with PI3K/Akt/mTOR signaling pathway in colorectal cancer (CRC) cells and inhibits tumor growth in vivo [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 2126. doi:10.1158/1538-7445.AM2017-2126
Abstract 2128: PDGFR beta signaling is required for hypoxia induced mitophagy in glioblastoma survival
Authors: Jung Jinkyu , Gilbert Mark R. , Park Deric M.
Published: July 2017

BACKGROUND: Platelet-derived growth factor (PDGF) signaling plays a key role in gliomagenesis. Glioblastomas express all PDGF ligands and both cell membrane receptors, PDGFRα and PDGFRβ, that are involved in pro-survival autocrine and paracrine loops. Our previous work demonstrated that expression of PDGFRβ is enriched in hypoxic glioblastoma tumor tissues. Also, induction of mitophagy is a well-known critical coping response to tissue hypoxia. We therefore investigated the role of PDGFRβ signaling cascade in regulating hypoxia-induced mitophagy of glioblastoma.

METHODS: Protein detection was performed by immunoblotting and immunofluorescence to determine changes in levels of target proteins upon RNA interference, treatment with PDGFRβ inhibitor, and ectopic gene transfection. MitoSox assay was used to measure mitochondrial reactive oxygen species (ROS). Tumor growth assays were performed in vitro and in vivo using subcutaneous tumor implantation model.

RESULTS: PDGFRβ signaling was essential for induction of hypoxia-mediated mitophagy in glioblastoma cells. Nix, a hypoxic responsive protein and regulator of mitophagy, was necessary for PDGFRβ-mediated glioblastoma survival. Inhibition of PDGFRβ signaling pathway killed glioblastoma cells by suppressing mitophagy and leading to subsequent elevation of mitochondrial ROS. Furthermore, interference of mitophagic response by blocking PDGFRβ signaling enhanced cell death even in chemotherapy-resistant tumor cells.

CONCLUSION: This work suggests a potential mechanism by which PDGFRβ inhibition could kill glioblastoma cells through suppression of NIX-mediated mitophagy. Manipulation of NIX and PDGFRβ pathway may provide novel therapeutic opportunities in chemoresistant tumor models.

Citation Format: Jinkyu Jung, Mark R. Gilbert, Deric M. Park. PDGFR beta signaling is required for hypoxia induced mitophagy in glioblastoma survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2128. doi:10.1158/1538-7445.AM2017-2128