bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 142: Exploiting replicative vulnerabilities to counter incomplete responses to PI3K/Akt/mTOR inhibition
Authors: Chopra Sameer , Niepel Mario , Jenney Anne , Hafner Marc , Sorger Peter
Published: July 2017

While a broad range of cancers harbor mutations that dysregulate PI3K-Akt-mTOR signaling, most small molecule drugs targeting this pathway have failed to demonstrate efficacy for the treatment of solid tumors. In this study, we investigated the mechanisms that account for drug efficacy and failure in PI3K-pathway dysregulated triple negative breast cancer (TNBC) cell lines using a diverse collection of 25 PI3K-Akt-mTOR inhibitors. Drug response phenotypes and changes in signaling were quantified using time-lapse imaging and quantitative single cell immunofluorescence microscopy, respectively. We identified GSK2126458 and Torin2 as having superior potency and efficacy in PI3K-pathway dysregulated TNBC. Unlike other PI3K pathway inhibitors, whose ineffectiveness arises from insufficient induction of apoptosis and variable inhibition of cell cycle progression at G1/S, GSK2126458 and Torin2 each rapidly induce caspase 3/7 activity and durably inhibit the proliferation of surviving cells. While the effectiveness of GSK2126458 in vitro appears to arise from near-complete suppression of PI3K-Akt-mTOR signaling, this approach has already proved unachievable in clinical trials. An alternative therapeutic strategy was identified by characterizing the mechanism of action of Torin2, a tool compound that inhibits both mTOR kinase and the DNA damage response kinases ATR, ATM, and DNA-PK. Unlike all other PI3K-Akt-mTOR inhibitors studied, Torin2 counters incomplete drug block at G1/S by concomitant induction of intolerable replication stress in S phase cells. The unique cell cycle pharmacology of Torin2 is recreated by combining inhibitors of mTOR and ATR/Chk1 kinases presently undergoing evaluation in clinical trials. In the context of combination therapy, where cytotoxicity arises from targeting S phase vulnerabilities rather than from PI3K-Akt-mTOR inhibition in G1, submaximal doses of mTOR kinase inhibitors are sufficient and confer benefit by preventing the outgrowth of cells that survive fractional killing from ATR/Chk1 inhibition. These findings suggest a novel strategy for mitigating the failure of precision monotherapy and have implications for the treatment of tumors where genetic lesions in the PI3K pathway co-occur with replicative vulnerabilities.

Citation Format: Sameer Chopra, Mario Niepel, Anne Jenney, Marc Hafner, Peter Sorger. Exploiting replicative vulnerabilities to counter incomplete responses to PI3K/Akt/mTOR inhibition [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 142. doi:10.1158/1538-7445.AM2017-142
Abstract 1432: Precision lung cancer medicine based on information on cancer and the host genomes
Authors: Kohno Takashi , Shiraishi Kouya , Yoshida Kazushi , Saito Motonobu , Okada Yukinori
Published: July 2017

Aberrations of oncogene, such as EGFR mutation; and ALK, RET, and ROS1 fusions, function as a driver in the development of lung adenocarcinoma (LADC). They are a solid target of therapy using tyrosine kinase inhibitors, as represented by a high response rate of RET-fusion positive LADC to vandetanib (LURET study, Yoh et al., Lancet Resp Med, 2016). Our genome-wide sequencing study revealed that oncogene aberration positive LADCs carry less numbers of mutations in cancer-related genes than negative ones (Saito, Cancer Res, 2015), indicating a small mutation burden in the development of the formers. Consistently, a clinical trial of anti-PD-1 therapy indicated that EGFR-mutation positive cases do not benefit well from the therapy (Borghaei et al., N Engl J Med. 2015). LADC driven by somatic EGFR mutations is more prevalent in East Asians (30-50%) than in European/Americans (10-20%). We recently revealed that variations in HLA-class II loci underlie the risk of the disease, by conducting a genome-wide association study of 3,173 patients and 15,158 controls, combined with imputation of HLA alleles using a Japanese-specific panel (Shiraishi et al., Nature Comm, 2016). The result indicates that LADC develops in vivo through interaction between somatic mutations and germline variations that modulate immune reaction. Therefore, efficacy of immune checkpoint blockade targeting therapy might also be influenced by such germline variations. On the other hand, oncogene-negative LADCs show a high mutation burden associated with nonsynonymous mutations in chromatin remodeling and other cancer-related genes. Thus, these cases would respond well to immune checkpoint blockade targeting therapies. We would like to discuss here precision lung cancer medicine based on information on cancer and the host genomes.

Citation Format: Takashi Kohno, Kouya Shiraishi, Kazushi Yoshida, Motonobu Saito, Yukinori Okada. Precision lung cancer medicine based on information on cancer and the host genomes [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 1432. doi:10.1158/1538-7445.AM2017-1432
Abstract 1438: The dynamics of genetic aberrations in Crohn's disease associated colorectal carcinogenesis
Authors: Hirsch Daniela D. , Wangsa Darawalee , Hu Yue , Zhu Jack , Petersen David , Edelman Daniel C. , Meltzer Paul S. , Tran Bao , Heselmeyer-Haddad Kerstin , Ried Thomas , Gaiser Timo
Published: July 2017

Crohn’s disease, a condition of chronic inflammation of the intestine, significantly increases the risk for the development of colorectal cancer (CRC). Sporadic CRCs are characterized by a specific pattern of genomic imbalances and a landscape of acquired gene mutations. In this study we aimed to compare CRCs that arise as a consequence of chronic inflammation in Crohn’s disease with sporadic CRCs.

We analyzed 26 Crohn’s disease associated CRCs, four matched dysplastic lesions, six matched inflamed mucosa samples, and two matched lymph node metastases using array comparative genomic hybridization, targeted sequencing (564 cancer related genes) and gene expression profiling. As a control, we used normal intestinal mucosa from the resection margin of these CRCs and 24 sporadic CRCs.

In general, CRCs that developed in patients with Crohn’s disease had a similar distribution of genomic imbalances compared to sporadic CRC. However, we identified distinct mutation signatures: in the Crohn's disease associated CRCs the most frequently mutated gene was TP53, which occurred in 65% of the samples. The second, third and fourth most frequently mutated genes were KRAS (27%), APC (23%) and PIK3CA (19%). In the control group of sporadically arising CRCs, the most commonly mutated gene was APC (75%), followed by KRAS (54%), TP53 (33%), SMAD3 (29%) and SMAD2 (25%). The genetic analyses of multiple lesions from individual patients revealed a high degree of intertumoral heterogeneity with diverse patterns of gene mutations and allowed the reconstruction of the sequence of genetic events during Crohn’s disease associated tumorigenesis. In contrast to sporadic colorectal carcinogenesis, TP53 mutations were observed as early and common events while APC mutations occurred rather late and were infrequent.

Our comprehensive molecular profiling of Crohn’s disease associated CRCs suggests that the genetic landscape of CRC is influenced by the activation of inflammation related pathways. Furthermore, our findings offer potential for establishing an early detection marker for dysplasia in patients with Crohn’s disease.

Citation Format: Daniela D. Hirsch, Darawalee Wangsa, Yue Hu, Jack Zhu, David Petersen, Daniel C. Edelman, Paul S. Meltzer, Bao Tran, Kerstin Heselmeyer-Haddad, Thomas Ried, Timo Gaiser. The dynamics of genetic aberrations in Crohn's disease associated colorectal carcinogenesis [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 1438. doi:10.1158/1538-7445.AM2017-1438
Abstract 1439: Genetic profiling of colitis-associated cancer indicates de novo carcinogenesis and the impact of chronic inflammation
Authors: Fujita Masashi , Matsubara Nagahide , Maejima Kazuhiro , Yamano Tomoki , Matsuda Ikuo , Hirota Seiichi , Ikeuchi Hiroki , Tomita Naohiro , Nakagawa Hidewaki
Published: July 2017

Background: Chronic inflammation is one of the major causes of carcinogenesis. Ulcerative colitis (UC) and Crohn’s disease (CD) increase the risk of colitis-associated cancer (CAC) development, and its biological and pathological characters are also distinct. However, the genetic mechanism of how chronic inflammation leads to CACs is still unclear.

Methods: We obtained frozen tumor tissues from 21 CAC patients and performed exome or whole-genome sequencing of the matched tumor-normal samples. We enumerated recurrently mutated genes and selected 43 genes among them for target capture. We then performed targeted resequencing of 84 FFPE specimens from CAC tissues. Totally, we made genomic profiles of 105 CACs.

Results: The most frequently mutated gene was TP53, whose mutation was found in 70 of 105 samples (67%), which is more prevalent in CACs than common colorectal cancers (CRCs). Somatic mutations of APC and KRAS were less prevalent (17 and 13 samples, respectively). Genes in the Wnt signaling pathway (APC, FBXW7, TCF7L2, and RNF43) were mutated in 31 samples, whereas those in the TGFβ pathway (TGFBR2, ACVR1B, SMAD2, SMAD4, LTBP4) were mutated in 25 samples. Mutational signature of CACs shows some differences from common CRCs.

Conclusion: Our results confirmed genetic differences for cancer development between CACs and common CRCs. Frequent TP53 mutations and less frequent APC mutations are consistent with the idea of “de novo” carcinogenesis than adenoma-carcinoma sequence. The association between the mutations and clinical information are also discussed.

Citation Format: Masashi Fujita, Nagahide Matsubara, Kazuhiro Maejima, Tomoki Yamano, Ikuo Matsuda, Seiichi Hirota, Hiroki Ikeuchi, Naohiro Tomita, Hidewaki Nakagawa. Genetic profiling of colitis-associated cancer indicates de novo carcinogenesis and the impact of chronic inflammation [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 1439. doi:10.1158/1538-7445.AM2017-1439
Abstract 1440: Germline loss-of-function alleles in Finnish colorectal cancer patients
Authors: Tanskanen Tomas , Hänninen Ulrika , Cajuso Tatiana , Kondelin Johanna , Katainen Riku , Hamberg Jiri , Välimäki Niko , Pitkänen Esa , Palin Kimmo , Aaltonen Lauri A.
Published: July 2017

Colorectal cancer, a major cause of cancer deaths worldwide, is often preventable by screening and surveillance, especially in patients at increased risk; however, its heritability is incompletely understood, and studies in isolated populations such as Finland may be valuable for gene discovery. We analyzed whole-genome or whole-exome sequencing data in 322 Finnish colorectal cancer cases of unknown etiology and 928 population-matched controls. To enrich for susceptibility alleles, cases were selected on the basis of early-onset colorectal cancer (age at diagnosis <50 years; 50/322, 16%), synchronous or metachronous colorectal cancer (30/322, 9.3%), familial colorectal cancer (134/322, 42%), personal history of noncolorectal cancer (93/322, 29%), or family history of at least two noncolorectal cancers (124/322, 39%). To increase the prior probability of pathogenicity of variants, the study was restricted to rare and low-frequency protein-coding loss-of-function variants (nonsense, frameshift, and essential splice site variants; allele frequency <3%). Single-variant and gene-level associations were tested, and genes with loss-of-function variants exclusively in cases were pinpointed. An independent set comprising 1,257 cases and 2,638 controls were genotyped using SNP arrays, and genotype imputation provided additional data on 225 (8.5%) of the 2,654 initially discovered loss-of-function variants. Principal component analysis was applied to correct for population structure. In association analyses, with a statistical power of at least 80% for a range of moderate-to-high effect sizes and low allele frequencies (e.g., odds ratio of 3 and allele frequency of 0.5%) at p <0.15, a total of 35 candidate colorectal cancer predisposition genes were identified, although none of them reached exome-wide significance. There were 21 genes with rare loss-of-function alleles in at least two cases but none of the sequenced controls. Whole-genome sequencing data from paired normal and tumor tissues were available in 243 cases, and potential second hits (wild-type allele losses or somatic point mutations) were found in 15 genes. These results may, through further analysis and replication, contribute to our knowledge of the genetic architecture and pathobiology of colorectal cancer susceptibility.

Citation Format: Tomas Tanskanen, Ulrika Hänninen, Tatiana Cajuso, Johanna Kondelin, Riku Katainen, Jiri Hamberg, Niko Välimäki, Esa Pitkänen, Kimmo Palin, Lauri A. Aaltonen. Germline loss-of-function alleles in Finnish colorectal cancer patients [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 1440. doi:10.1158/1538-7445.AM2017-1440
Abstract 1441: A comprehensive cis-eQTL analysis revealed target genes in breast cancer susceptibility loci identified in genome-wide association studies
Authors: Guo Xingyi , Lin Weiqiang , Cai Qiuyin , Shi Jiajun , Sun Yaqiong , Pan Xiao , Han Mi-Ryung , Wen Wanqing , Li Bingshan , Long Jirong , Chen Jianghua , Zheng Wei
Published: July 2017

Genome-wide association studies (GWAS) have identified approximately 107 common single nucleotide polymorphisms (index SNPs) for breast cancer risk. The target genes and underlying mechanisms for the large majority of the identified associations remain unknown. We conducted a cis-expression quantitative trait loci (cis-eQTL) analysis using transcriptome data from the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) (N = 1,981), The Cancer Genome Atlas (TCGA) (N = 458), and the Genotype-Tissue Expression (GTEx) project (N = 183). We identified a total of 58 genes including SSBP4 at Benjamini-Hochberg adjusted P < 0.05 in at least one dataset and another gene, PAX9, at P < 0.05 with consistent association directions in all three datasets. Using data from the Encyclopedia of DNA Elements (ENCODE), we selected functional SNPs and showed that some alternative alleles could significantly change promoter activities of their target genes compared to reference alleles using luciferase reporter assays. The effects of target gene expression for those alleles were in line with eQTL observations. In addition, we validated the genes SETD9 and SSBP4 using Sequenom allelotype technique from 235 adjacent normal breast tissues and observed the allelic-specific expression associated with their index SNPs. This study revealed novel biological mechanisms for associations of genetic susceptibility risk loci for breast cancer.

Citation Format: Xingyi Guo, Weiqiang Lin, Qiuyin Cai, Jiajun Shi, Yaqiong Sun, Xiao Pan, Mi-Ryung Han, Wanqing Wen, Bingshan Li, Jirong Long, Jianghua Chen, Wei Zheng. A comprehensive cis-eQTL analysis revealed target genes in breast cancer susceptibility loci identified in genome-wide association studies [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 1441. doi:10.1158/1538-7445.AM2017-1441
Abstract 1445: Understanding the 8q24 colorectal cancer risk locus via CRISPR/Cas9 scarless genome editing
Authors: Coggins Nicole , Stultz Jacob , Segal David , Carvajal-Carmona Luis
Published: July 2017

Colorectal Cancer (CRC) is one of the leading causes of mortality in the US, being the third most common cancer among both men and women. While an exact cause of CRC has not yet been elucidated, the existence of a clear heritable genetic component has been established. With the recent surge of data from Genome-Wide Association Studies, a handful of CRC-associated loci have been identified, each containing numerous Single Nucleotide Polymorphisms (SNPs). We hypothesize that among the ~25 loci associated with increased risk for CRC, there are driver SNPs functioning to contribute to initiation or progression of CRC development. It is crucial, in order to enhance our understanding CRC tumorigenesis, to extract these functional variants from the pool of associated SNPs and validate their causative significance within the cell. To model these functional SNPs, we have developed a novel “scarless” isolation pipeline for selecting isogenic clones with the desired single-base edit without selection markers following CRISPR-Cas9 mediated HDR. With this pipeline, we have successfully modeled our first selected SNP, rs6983267, from the 8q24 risk locus in HCT-116 cells, producing the heterozygous genotype (G/T) from the parental homozygous risk (G/G) genotype. Rs6983267 is located within a known c-Myc enhancer and has been shown to exert risk-allele specific increase in enhancer activity. Oncogenic c-Myc is known to play a significant role in CRC pathogenesis. In line with previous studies, we observe a slight decrease in c-Myc expression in our heterozygous clones compared to wildtype homozygous risk. Moreover, we observe a preferential binding of the transcription factor in control of c-Myc transcriptional regulation, TCF7L2, to the risk allele over the reference allele while binding of proximal factors such as CTCF show no allelic preference. Interestingly, we also see significant changes in expression of target genes of the WNT signaling pathway. Dysregulation of WNT is a hallmark characteristic of CRC. These changes indicate there is indeed an effect of the risk allele of rs6983267 on overall WNT activity in CRC cells due to increased binding of transcription factor TCF7L2. This novel SNP editing pipeline provides a method to study precise effects of single base changes located anywhere in the genome. Utilizing it to model other risk SNPs will enable the enhancement of our current understanding of GWAS-identified risk loci in CRC pathogenesis at the molecular level.

Citation Format: Nicole Coggins, Jacob Stultz, David Segal, Luis Carvajal-Carmona. Understanding the 8q24 colorectal cancer risk locus via CRISPR/Cas9 scarless genome editing [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 1445. doi:10.1158/1538-7445.AM2017-1445
Abstract 1454: Estrogen receptor signaling in FTE of BRCA mutation carriers
Authors: Dodds Leah V. , Nelson Omar L. , Sowamber Ramlogan , Rodrigues Andres , Castro Victoria de , Henry Wendell , Morales Guillermo , Slomovitz Brian , Shaw Patricia , George Sophia H.
Published: July 2017

Genetic and reproductive factors predicate epidemiological risk factors underlying epithelial ovarian cancer. The fallopian tube epithelia (FTE), the presumptive etiological site of high-grade serous ovarian cancer (HGSC), is a hormonal responsive tissue. Estrogen is known to promote cell proliferation and its metabolism produces reactive oxygen species that damage DNA and promote tumorigenesis. Estrogen receptor (ER) is rarely mutated, amplified or deleted in HGSC, yet only 10% of patients respond to anti-estrogen treatment, suggesting that intrinsic variables to the ER pathway contribute to this clinical outcome. TP53 mutations occur in almost 100% of HGSCs, indicating that mutated p53 supports a model as an early event in the pathogenesis of HGSC. We hypothesized that in the presence of dysfunctional p53, subsequent promiscuous binding of ER will yield aberrant signaling, ultimately significantly contributing to cellular transformation. Mutant p53 and ER co-localize in FTE cells, suggesting potential synergy. We established cell lines with p53 mutations and treated them with estradiol, an estrogen analog, to observe any changes in response. The genome binding sites of ER-regulated transcription factors were then identified and mapped by whole genome chromatin immunoprecipitation-deep sequencing (ChIP-Seq). The data generated will facilitate the development of gene signatures that will predict response to anti-estrogen therapy in serous ovarian cancer patients, and contribute to the discovery of biomarkers to more accurately identify patients who will benefit from hormonal therapies.

Citation Format: Leah V. Dodds, Omar L. Nelson, Ramlogan Sowamber, Andres Rodrigues, Victoria de Castro, Wendell Henry, Guillermo Morales, Brian Slomovitz, Patricia Shaw, Sophia H. George. Estrogen receptor signaling in FTE of BRCA mutation carriers [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 1454. doi:10.1158/1538-7445.AM2017-1454
Abstract 147: Metformin suppresses triple-negative breast cancer stem cells by targeting KLF5 for degradation
Authors: Shi Peiguo , Zhou Zhongmei , Liu Rong , Chen Ceshi
Published: July 2017

Out of the breast cancer subtypes, triple-negative breast cancer (TNBC) has the poorest prognosis without effective targeted therapies. A stem cell transcription factor KLF5 is over-expressed in basal type TNBC and promoting cell proliferation, survival and stemness. Previously, we demonstrated that Mifepristone suppresses basal TNBC stem cells by down-regulating KLF5 expression through inducing the expression of miR-153. In this study, Metformin, a first-line drug for type 2 diabetes mellitus, was demonstrated to target breast cancer stem cells selectively. However, the efficiency and the mechanism of action of metformin in TNBC are unclear. We demonstrated that metformin decreased the percentage of TNBC stem cells partially through the downregulation of the expression of KLF5 and its downstream target genes, such as Nanog and FGF-BP1, in TNBC cell lines. Metformin induced GSK3β-mediated KLF5 protein phosphorylation and degradation through the inhibition of PKA activity in TNBC cells. Consistently, PKA activators increased the expression levels of KLF5. We observed a positive correlation between p-CREB and KLF5 protein levels in human TNBC samples. These findings suggest that metformin suppresses TNBC stem cells partially through the PKA-GSK3β-KLF5 signaling pathway.

Citation Format: Peiguo Shi, Zhongmei Zhou, Rong Liu, Ceshi Chen. Metformin suppresses triple-negative breast cancer stem cells by targeting KLF5 for degradation [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 147. doi:10.1158/1538-7445.AM2017-147
Abstract 1474: Epigenetic silencing of microRNA-137 enhances ASCT2 expression and tumor glutamine metabolism
Authors: Daibiao Xiao , Dong Junli , Zhao Zihan , Ren Ping , Li Cong , Hu Yufeng , Shi Jianguo , Su Hexiu , Wang Zhaojing , Liu Hudan , Li Bo , Gao Peng , Qing Guoliang
Published: July 2017

Cancer cells amplify the expression of ASC amino acid transporter 2 (ASCT2, also called SLC1A5), a high-affinity glutamine carrier protein, to coordinate metabolic reprogramming and malignant transformation. Yet genetic and/or epigenetic mechanisms underlying the control of ASCT2-mediated glutamine metabolism remain to be clarified. Combined in-silico algorithms with systemic experimental screening, we herein identify the tumor suppressor miR-137 as an essential regulator that targets ASCT2 mRNA and cancer cell glutamine metabolism. Metabolic analysis shows that miR-137 derepression, similar to ASCT2 inactivation, significantly inhibits glutamine consumption and TCA cycle anaplerosis. Mechanistically, methyl-CpG binding protein 2 (MeCP2) and DNA methyltransferases (DNMTs) cooperate to promote active methylation of the miR-137 promoter and its decreased transcription, which conversely enhances ASCT2 expression and glutamine metabolism. As such, expression between miR-137 and ASCT2 is inversely correlated in multiple human cancer types, including colorectal carcinomas, glioblastomas, prostate and pancreatic cancers. These findings thus elucidate a universal mechanism responsible for ASCT2 deregulation in human cancers, revealing a molecular link between miR-137, ASCT2 and tumor metabolism.

Citation Format: Xiao Daibiao, Junli Dong, Zihan Zhao, Ping Ren, Cong Li, Yufeng Hu, Jianguo Shi, Hexiu Su, Zhaojing Wang, Hudan Liu, Bo Li, Peng Gao, Guoliang Qing. Epigenetic silencing of microRNA-137 enhances ASCT2 expression and tumor glutamine metabolism [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 1474. doi:10.1158/1538-7445.AM2017-1474
Abstract 1478: Curcumin inhibits epithelial-mesenchymal transition and invasion in breast cancer cells by controlling miR-34a expression
Authors: Gallardo Marcela , Ponce-Cusi Richard , Calaf Gloria M.
Published: July 2017

Breast cancer in advanced stages tends to develop metastases and / or chemoresistance, in both cases therapeutic options are limited and have low probability of success, which represents the biggest obstacle in reducing mortality from this disease. There is a close connection between the Epithelial-Mesenchymal Transition (EMT) process of cancer cells and the acquisition of invasive and metastatic ability. Numerous EMT mediators have been described in cancer and among them miRNAs play a fundamental role in regulating such process, suggesting that it could be a therapeutic target to address this phenotype. Curcumin (diferuloylmethane) is a derivative compound of Curcuma longa that has therapeutic properties in various cancers as blocking initiation and tumor progression through its anti-inflammatory, antioxidant, proapoptotic, antiangiogenic and antimetastatic effects. The role of curcumin on EMT in non-cancerous breast cells MCF-10F and in breast cancer cell lines MCF-7 and MDA-MB-231 was evaluated. This work shows that in all these cell lines curcumin induced the expression of tumor suppressor microRNA miR-34a and repressed the expression of several genes involved in EMT and metastasis as Axl, Slug, Twist, N-cadherin, vimentin, fibronectin, among others. Consequently, curcumin inhibited the migration and invasiveness in these cells, irrespective of the expression of estrogen and progesterone receptors and p53 mutational status. Blockade of miR-34a by transfection with antagomiR-34a inhibited the effect of curcumin on EMT genes and on the migratory/invasive potential of cells indicating that miR-34a plays a central role in the Curcumin-mediated suppression of EMT and invasion. Therefore, results confirm the suppressive effect of curcumin on EMT and invasion in breast cancer cells, showing that such substance exerts this effect by inducing expression of miRNA miR-34a and consequently the repression of several of its target genes. Supported by Tarapacá University, Arica, Chile (GMC).

Citation Format: Marcela Gallardo, Richard Ponce-Cusi, Gloria M. Calaf. Curcumin inhibits epithelial-mesenchymal transition and invasion in breast cancer cells by controlling miR-34a expression [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 1478. doi:10.1158/1538-7445.AM2017-1478
Abstract 148: A dual and selective small molecule inhibitor of EGFR and PI3 kinase shows promising preclinical activity against KRAS and BRAF mutant colorectal tumors
Authors: Maust Joel D. , Ziemke Elizabeth K. , Frankowski-McGregor Christy L. , Ku Jun Beom , Mumby Rachel , Hardiman Karin M. , Whitehead Christopher E. , Sebolt-Leopold Judith S.
Published: July 2017

Agents targeting epidermal growth factor receptor (EGFR) have met with limited success in the clinical management of colorectal cancer (CRC). Mutations in KRAS, BRAF, and PIK3CA are important drivers of resistance to EGFR-targeted therapy. Conversely, EGFR-mediated feedback mechanisms serve to mediate resistance to MEK inhibitor-based treatment of CRC by reactivating MAP kinase signaling. Our central hypothesis is that a dual small molecule inhibitor that potently and selectively targets only EGFR and PI3KA, when combined with a MEK inhibitor, will be highly efficacious against subpopulations of BRAF mutant or KRAS mutant colorectal cancers that are dependent upon these kinase molecules to drive tumor progression. Employing a computational modeling approach, we exploited the known binding modes of structurally related ATP binding site inhibitors of EGFR and PI3K to design small molecules that simultaneously inhibit both kinases in a selective manner. To the best of our knowledge, the lead compound MTX-211, whose binding mode is flipped in PI3K compared to EGFR, represents a first in class selective inhibitor of these two critical oncogenic kinases. MTX-211 exhibits a favorable pharmaceutical and selectivity profile, possessing sub- to low nanomolar potency against both targets, >70% oral bioavailability, strong pharmacodynamic modulation of both EGFR and PI3K signaling, and strong in vivo single agent efficacy against multiple BRAFmt and KRASmt colorectal cancer models, as evidenced by T/C values of 29 to 36% after 10-14 days of oral dosing of 50 mg/kg. A significantly higher degree of in vivo activity is seen when MTX-211 is co-administered with the MEK inhibitor trametinib (>400% increase in survival compared to single agent arms), lending support for this polypharmacology approach over triple drug combination strategies. Based on its promising therapeutic profile, MTX-211 is the focus of an ongoing mouse trial of a large panel of patient-derived xenograft BRAFmt and KRASmt CRC models to inform the design of future human clinical trials.

Citation Format: Joel D. Maust, Elizabeth K. Ziemke, Christy L. Frankowski-McGregor, Jun Beom Ku, Rachel Mumby, Karin M. Hardiman, Christopher E. Whitehead, Judith S. Sebolt-Leopold. A dual and selective small molecule inhibitor of EGFR and PI3 kinase shows promising preclinical activity against KRAS and BRAF mutant colorectal tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 148. doi:10.1158/1538-7445.AM2017-148
Abstract 1484: Genome wide study reveal microrna based methylation phenotype in oral cancer
Authors: Roy Roshni , Chatterjee Aniruddha , Sarkar Navonil De , Roy Bidyut
Published: July 2017

Introduction: Oral cancer is one of the leading causes of cancer burden in India. Studies over the years have enforced the role of deregulated microRNA expression in oral cancer development and progression. Incidentally not much is known about the cause of microRNA deregulation or to what extent can it be attributed to methylation. Established genome wide microarray platforms like 450K Illumina Bead Chip have probes for very limited number of microRNAs along with restriction on distance of the probes from microRNA transcription start site. We have used genome wide methylation sequencing approach RRBS to get deeper insight on microRNA methylation.

Aim: Genome wide methylation profile of 15 paired oral cancer and adjacent normal tissue was compared to generate a detailed map of microRNA methylation in oral cancer. The methylation results were further correlated to microRNA expression data generated on a subset of these samples.

Methodology: RRBS based global methylation sequencing of 15 pairs of samples was conducted on HiSeq 2500 with an average 10X depth. Analyses were done using DMAP software. Previously generated TLDA based microRNA expression data was used for correlation analysis.

Result: Similar to protein coding genes, microRNAs also showed methylation based clustering. Interestingly majority of methylation hits were more than 2kb upstream of miRNA transcription start site which is generally not considered in known microarrays. Distribution of hypo and hyper methylation sites is different across the various CpG features like cores and shelves as well as across chromosomes. MicroRNAs like mir-181c, miR-99b, miR-23a among others showed significant negative correlation between methylation frequency and expression level. IPA based pathway analysis emphasized repression of apoptosis and cell death pathways along with activation of cell proliferation and colony formation.

Conclusion: Understanding the role of methylation in microRNA deregulation could help us detect and possibly prevent a chain of events, which lead to disrupted pathways eventually leading to cancer, at the onset.

Note: This abstract was not presented at the meeting.

Citation Format: Roshni Roy, Aniruddha Chatterjee, Navonil De Sarkar, Bidyut Roy. Genome wide study reveal microrna based methylation phenotype in oral 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 1484. doi:10.1158/1538-7445.AM2017-1484
Abstract 1492: Chemical approaches to development of mitochondrial-targeted Hsp90 inhibitor in anti-cancer therapeutics: Mechanism and structure change of mitochondrial Hsp90
Authors: Hu Sung , Yoon Nam Gu , Kang Byoung Heon
Published: July 2017

Tumor Necrosis Factor Receptor-Associated Protein 1 (TRAP1), a member of the heat shock protein 90 (Hsp90) which located in mitochondria, is thought to promote tumor cell survival and to reprogram energy metabolism in cancer. Previous studies have demonstrated that the inactivation of TRAP1 selectively induced mitochondrial dysfunction and cell death in cancer cells. Therefore, TRAP1 has been suggested as an emerging target protein for anti-cancer drug development. Isopropyl amine of the Hsp90 inhibitor, PU-H71, was replaced with the mitochondria-targeting moiety, triphenyphosphonium, to produce the mitochondria-accumulating TRAP1 inhibitor, SMTIN-P01. To further optimize SMTIN-P01, we have synthesized several SMTIN-P01 derivatives including TPP-PU-X03 with potent TRAP1 inhibitory activities. TPP-PU-X03 increased TRAP1 ATPase enzyme activity while suppressing chaperone activity, suggesting asymmetric effect on dimeric TRAP1 chaperone functions. Electron microscopic analyses showed TPP-PU-X03 shift TRAP1 conformation from open to close conformation, while other TRAP1 or Hsp90 inhibitors stabilizes open conformation. Importantly, TPP-PU-X03 showed improved mitochondria dysfunction and enhanced cytotoxicity to various cancer cells in vitro and in vivo. Collectively, the structure based optimization of current TRAP1 inhibitors may generate potent anti-cancer drugs with novel mechanisms of action.

Citation Format: Sung Hu, Nam Gu Yoon, Byoung Heon Kang. Chemical approaches to development of mitochondrial-targeted Hsp90 inhibitor in anti-cancer therapeutics: Mechanism and structure change of mitochondrial Hsp90 [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 1492. doi:10.1158/1538-7445.AM2017-1492
Abstract 1502: The link between NRF2 and mitochondria through the regulation of miR-181c/mitochondria-encoded cytochrome c oxidase subunit-1
Authors: Kwak Mi-Kyoung , Jung Kyeong-Ah , Kim Donghyeok , Lee Sujin
Published: July 2017

The nuclear factor erythroid 2-related factor 2 (NRF2) pathway is involved in the environmental resistance of cancers by enhancing the antioxidant capacity. In the current study, we investigated the potential link between NRF2 and mitochondrial function in cancer cells. Global miRNA expression analysis of HT29 and HCT116 identified miR-181c as an NRF2-silencing-inducible miRNA, and miR-181c elevation was associated with the decrease in mitochondria-encoded cytochrome c oxidase subunit-1 (MT-CO1), a mitochondrial genome-encoded complex IV subunit of the electron transport chain. As a result of decreased complex IV activity, NRF2-silenced cancer cells exhibited reduced levels of mitochondrial membrane potential (MMP), oxygen consumption rate, and ATP production. Notably, these changes induced adaptive activation of AMP-activated protein kinase-α (AMPKα) and thereby, NRF2-silenced cells were more vulnerable to AMPK inhibitor-induced growth suppression. Similarly, mouse tumor xenografts derived from NRF2-silenced HT29 exhibited MT-CO1 reduction and AMPKα activation, thereby increasing responsiveness to the AMPK inhibitor treatment. Collectively, we showed a novel link of NRF2 to cancer mitochondria and AMPK signaling by elucidating miR-181c/MT-CO1 signaling as an underlying molecular mechanism. These results also suggest that it may an effective strategy to inhibit both NRF2 and AMPK to control adaptive tumor responses.

Citation Format: Mi-Kyoung Kwak, Kyeong-Ah Jung, Donghyeok Kim, Sujin Lee. The link between NRF2 and mitochondria through the regulation of miR-181c/mitochondria-encoded cytochrome c oxidase subunit-1 [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 1502. doi:10.1158/1538-7445.AM2017-1502
Abstract 1505: Breast cancer cells treated with mitochondria targeted redox active agents induce mitophagy
Authors: Biel Thomas , Rao Ashutosh
Published: July 2017

Triphenylphosphonium (TPP) conjugated agents induce mitochondrial dysfunction in cancer cells. However, the onset of mitophagy to remove the dysfunctional mitochondria is unknown. Here, a series of mitochondria targeted redox active agents (MTA) that contain TPP were used to investigate mitochondrial dysfunction and mitophagy in MDA-MB-231 cells as compared to MCF-12A cells. Three different MTAs were identified to induced mitochondrial depolarization and enhanced autophagic flux selectively in MDA-MB-231 cells. Mitochondrial reactive oxygen species generation and respiration indicated that MDA-MB-231 cells had a heighten sensitivity to MTA treatments. Using stably expressing mt-mKeima MDA-MB-231 and MCF-12A cell lines, a non-cell type selective decline in mitochondrial alkalinity and altered mitochondrial morphology was detected. Furthermore, FACS analysis of mt-mKeima revealed MTAs induced lysosomal dependent mitochondrial degradation in the presence of Bafilomycin, a lysosomal inhibitor. To confirm MTAs induced mitochondrial autophagy in MDA-MB-231 cells, MitoTracker Red preloaded GFP-LC3 expressing MDA-MB-231 cells were used to identify autophagosomes containing mitochondria using confocal microscopy, in addition to coimmunoprecipitation for the detection of an endogenous autophagy-related protein complex, and immunoblot to for mitochondrial PINK1 accumulation. To translate these in vitro studies to an in vivo rat SST-2 xenograph breast cancer model, tumor mitochondrial extracts from rats treated with MitoQ demonstrated an accumulation of mitochondrial PINK1. Collectively, these data suggest that mitochondrial agents selectively caused mitochondrial depolarization, PINK1 accumulation and mitophagy in MDA-MB-231 cancer cells as compared to MCF-12A healthy cells.

Citation Format: Thomas Biel, Ashutosh Rao. Breast cancer cells treated with mitochondria targeted redox active agents induce mitophagy [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 1505. doi:10.1158/1538-7445.AM2017-1505
Abstract 1517: AKT inhibition induces neuroendocrine phenotype in prostate cancer cells
Authors: Chen RuiQi , Li Yinan , Dong Xuesen
Published: July 2017

Androgen receptor (AR) signaling pathway inhibition (ARPI) is the primary treatment for locally advanced, recurrent, or metastatic prostate cancer. While ARPI is effective in short term, a fatal relapse is inevitable. The AKT signaling pathway inhibition has been investigated under multiple ongoing clinical trials as a co-therapeutic target with ARPI. The AKT signaling pathway is targeted due to its role in tumorigenesis, prevalent over-activation, and reciprocal activation upon ARPI in prostate cancer. However, this novel combination therapy may in fact facilitate PCa to progress into one of the most lethal subtypes called neuroendocrine (NE) prostate cancer (NEPC). Specifically, evidence has shown that ARPI contributes to NEPC progression at least in part by down-regulating the expression of RE-1 Silencing Transcription Factor (REST). Loss of REST is a hallmark of NEPC progression because REST functions as a negative master regulator in neurogenesis by suppressing genes required for neural differentiation. Similar to ARPI, our studies found that AKT inhibition reduced REST protein expression and increased NEPC markers in multiple prostate cancer cell lines. We also showed that the loss of REST upon AKT inhibition was through protein degradation mediated by an E3-ubiquitin ligase TRCP, which recognizes a phosphorylated REST degron region to recruit ubiquitins. In vivo ubiquitination assays confirmed the elevated REST ubiquitination after the treatment of PI3K inhibitors. Furthermore, mutations within the REST degron region reversed the TRCP-mediated REST ubiquitination and degradation. Finally, co-treatment of AKT pathway inhibition and ARPI showed aggravated REST depletion and increased NE markers in the prostate cancer cell line LNCaP. Collectively, these findings indicate that AKT pathway inhibition can induce NE phenotype in prostate cancer cells via REST protein degradation. This study may provide a caution to the ARPI/AKT co-target strategy as this strategy can potentially facilitate NEPC development.

Citation Format: RuiQi Chen, Yinan Li, Xuesen Dong. AKT inhibition induces neuroendocrine phenotype in prostate 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 1517. doi:10.1158/1538-7445.AM2017-1517
Abstract 1524: BCL6 modulates the TP53 and STAT pathways in glioma
Authors: Chen Ye , Xu Liang , Dutra-Clarke Marina , Mayakonda Anand , Lin De-Chen , Koh Lynnette , Chong Yuk Kien , Sandanaraj Edwin , Madan Vikas , Yang Henry , Doan Ngan , Said Jonathan W. , Yong William H. , Müschen Markus , Ang Beng Ti , Tang Carol , Breunig Joshua J. , Koeffler Phillip
Published: July 2017

Glioblastoma multiforme (GBM) remains the most aggressive brain malignancy with little improvement in prognosis or therapy for decades. Recently, we identified BCL6, also known as ZBTB27, to be a novel oncogene in GBM. In this study, we performed IHC analysis of 153 primary human glioma specimens and 8 normal brain samples. BCL6 expression is robustly elevated in tumor samples and positively correlated with glioma pathological grade. High BCL6 expression strongly predicts a worse prognosis of GBM patients. Depletion of BCL6 in human GBM cells reduced the incorporation of BrdU, promoted the cellular senescence and inhibited the growth of human GBM cells in vivo. Next, genome-wide occupancy of BCL6 in GBM cells was characterized by ChIP-seq assay. Genomic regions centered on BCL6 peaks are co-enriched with RNA-Pol II and flanked with strong H3K27ac and H3K4me3 modifications. MYC and two long non-coding RNAs MALAT1 and NEAT1 were identified as novel BCL6 targets in GBM. Moreover, pathway enrichment analysis of BCL6 peak-associated genes reveals a significant enrichment of JAK-STAT, TP53, ERBB and MAPK pathways. We demostrated further that BCL6 represses the TP53 pathway and promotes the JAK-STAT pathway activation in GBM cells. Together, our findings uncover potential downstream targets and provide a better understanding of BCL6 function in GBM.

Citation Format: Ye Chen, Liang Xu, Marina Dutra-Clarke, Anand Mayakonda, De-Chen Lin, Lynnette Koh, Yuk Kien Chong, Edwin Sandanaraj, Vikas Madan, Henry Yang, Ngan Doan, Jonathan W. Said, William H. Yong, Markus Müschen, Beng Ti Ang, Carol Tang, Joshua J. Breunig, Phillip Koeffler. BCL6 modulates the TP53 and STAT pathways in glioma [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 1524. doi:10.1158/1538-7445.AM2017-1524
Abstract 1529: Scutellaria baicalensis targets the hypoxia-inducible factor-1α and attenuates ovarian cancer growth
Authors: Hussain Imran , Waheed Sana , Ahmad Kashif A. , Pirog John E. , Syed Viqar
Published: July 2017

Hypoxia-inducible factor-1alpha (HIF-1α), a transcription factor important for maintaining cellular oxygen homeostasis, is aberrantly upregulated in many tumors and implicated in angiogenesis, metastasis and drug resistance. Therefore, developing treatments that target HIF-1α may be a viable therapeutic approach. For centuries, traditional Chinese medicine has used herbs, such as Scutellaria baicalensis (SB), as a natural remedy for tumors. However, the mechanisms by which SB inhibits tumor growth are not known. We have previously reported that SB inhibits cancer cell proliferation and targets NF-κB in endometrial and ovarian cancers and TGF-β in endometrial cancers. In this study, we examined the effects of SB on HIF-1α protein levels in three ovarian cancer cell lines, SKOV3, OVCA 429, and OVCA 420, grown under normoxic and hypoxic conditions. When treated daily with SB, cancer cells showed a decrease in HIF-1α expression after 48 hours. Investigation into the molecular mechanisms of SB-induced inhibition revealed a significant reduction of HIF-1α accumulation in cells treated with cycloheximide, a protein synthesis inhibitor. Further decrease of HIF-1α accumulation was seen when cycloheximide was combined with SB. Additionally, SB- induced HIF-1α proteasomal degradation was prevented by treatment of cells with proteasomal inhibitor MG132 and chloroquine, lysosome inhibitor, abrogated SB-induced inhibition of HIF-1α. Activation of PI3K/AKT and MAPK/ERK is shown in cancers. SB reduced levels of phospho-AKT and phospho-extracellular signal-related kinase (ERK) in ovarian cancer cells. Furthermore, pretreatment of cells with LY294002 (phosphoinositide 3-kinase inhibitor) and PD98059 (mitogen-activated protein kinase kinase inhibitor) reduced HIF-1α expression comparable to SB-treated cells. Hypoxia-induced cisplatin resistance is a major challenge in therapy of ovarian tumors. SB reduces the proliferation and reverses cisplatin resistance in ovarian cancer cells by attenuating the expression of HIF-1α. Taken together, the findings suggest that targeting HIF-1α with SB could be an effective treatment strategy for ovarian cancer and that SB can improve the sensitivity of cells to cisplatin.

Note: This abstract was not presented at the meeting.

Citation Format: Imran Hussain, Sana Waheed, Kashif A. Ahmad, John E. Pirog, Viqar Syed. Scutellaria baicalensis targets the hypoxia-inducible factor-1α and attenuates ovarian cancer growth [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1529. doi:10.1158/1538-7445.AM2017-1529