bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2469: The B-cell lymphoma specific aptamer C10.36 binds a ribonucleoprotein complex on the cell surface of cancer cells
Authors: Tonapi Sonal S. , Duncan Janet E. , Rosenow Matthew , Richards Melissa , Tinder Teresa L. , O'Neill Heather A. , Miglarese Mark R. , Spetzler David , Famulok Michael , Mayer Günter
Published: July 2017

Aptamers have recently gained prominence for their diagnostic and therapeutic potential. The DNA aptamer C10.36 forms a G-quadruplex and has been shown to bind the Ramos Burkitt’s lymphoma cell line. However, its binding partner on the cell surface remains unknown. Here we report on the identification of the molecular target of C10.36, which suggests its application in the therapy of B-cell lymphoma and leukaemia. Aptamer-affinity purification, followed by LC-MS/MS revealed unique proteins pulled down with C10.36 associated with Ramos cells but not Jurkat, a T-cell lymphocyte cell line. The majority of the identified target molecules were found to be associated within ribonucleoprotein complexes, of which the abundant and consistent ones belong to the nucleolin complex including nucleolin (NCL) itself and its interacting partners, i.e. nucleophosmin (NPM1), heterogeneous nuclear ribonucleoprotein (HNRNP) family members such as HNRNP C1C2 and U, rRNA 2'-O-methyltransferase fibrillarin (FBL), actin (ACTB), nucleolar RNA helicase 2 (DDX21), and proline- and glutamine-rich splicing factors (SFPQ). All proteins identified in the above ribonucleoprotein complex are aberrantly expressed on the surface of several disparate cancer cell types and have been shown to play an oncogenic role in cancer. Another G-rich anti-NCL aptamer, AS1411, has been shown to induce cell death in >100 cancer cell lines. Therefore, we tested the effect of C10.36 on viability of Ramos and other non-Hodgkin B-cell lymphoma (NHL) cancer cell lines. Our results indicate that C10.36 treatment causes specific cell death of certain lymphoma cell lines such as Ramos but not Jurkat cells. The present study identifies C10.36 as a novel anti-B cell lymphoma aptamer and underscores its potential for the development of a new targeted therapy to treat B-cell lymphomas.

Citation Format: Sonal S. Tonapi, Janet E. Duncan, Matthew Rosenow, Melissa Richards, Teresa L. Tinder, Heather A. O'Neill, Mark R. Miglarese, David Spetzler, Michael Famulok, Günter Mayer. The B-cell lymphoma specific aptamer C10.36 binds a ribonucleoprotein complex on the cell surface of 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 2469. doi:10.1158/1538-7445.AM2017-2469
Abstract 2470: Compromised BRCA1-PALB2 interaction is associated with breast cancer risk
Authors: Foo Tzeh Keong , Tischkowitz Marc , Simhadri Srilatha , Boshari Talia , Burke Kathleen A. , Berman Samuel H. , Zayed Nadia , Ding Yuan Chun , Neuhausen Susan L. , Weigelt Britta , Reis-Filho Jorge S. , Foulkes William D. , Xia Bing
Published: July 2017

The major breast cancer suppressor proteins BRCA1 and BRCA2 play essential roles in homologous recombination (HR)-mediated DNA repair, which is thought to be critical for tumor suppression. The two BRCA proteins are physically and functionally linked by a third tumor suppressor, PALB2 (partner and localizer of BRCA2), in the HR pathway. Heterozygous PALB2 mutation carriers have increased risk of breast, ovarian and pancreatic cancer. While truncating mutations in BRCA genes are generally pathogenic, interpretations of missense variants remains a challenge. To date, patient-derived missense variants that disrupt PALB2 binding have been identified in BRCA1 and BRCA2; however, there has not been sufficient evidence to establish their pathogenicity in humans. Variants in PALB2 that disrupt either its BRCA1 or BRCA2 binding have not been reported. Here, we report on the identification of a novel PALB2 variant, c.104T>C [p.L35P], that segregated in a family with a strong history of breast cancer. Functional analyses showed that L35P abrogates the PALB2-BRCA1 interaction, resulting in impaired HR and sensitivity to platinum salts and PARP inhibitors. Whole-exome sequencing of breast tumor from a c.104T>C carrier revealed a somatic, truncating mutation in the second allele of PALB2, with the tumor displays hallmark genomic features of tumors with BRCA mutations and HR defects. Using a combination of traditional clinical genetics, tumor whole-exome sequencing and in-depth functional analyses, we have provided direct evidence to cement the pathogenicity of L35P. Parallel analyses of other germline variants in the PALB2 N-terminal BRCA1-binding domain also identified multiple variants that affect HR function to varying degrees, suggesting their possible contribution to cancer development. Our findings establish p.L35P as the first pathogenic missense mutation in PALB2 identified to date and directly demonstrate the requirement of the PALB2-BRCA1 interaction for breast cancer suppression.

Citation Format: Tzeh Keong Foo, Marc Tischkowitz, Srilatha Simhadri, Talia Boshari, Kathleen A. Burke, Samuel H. Berman, Nadia Zayed, Yuan Chun Ding, Susan L. Neuhausen, Britta Weigelt, Jorge S. Reis-Filho, William D. Foulkes, Bing Xia. Compromised BRCA1-PALB2 interaction is associated with breast cancer risk [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 2470. doi:10.1158/1538-7445.AM2017-2470
Abstract 2472: Defining the role of the XAB2 complex during homologous recombination
Authors: Onyango David O. , Stark Jeremy
Published: July 2017

Several factors associated with RNA processing are important for homologous recombination (HR), but the mechanistic links between these processes remain poorly understood. To this end, we have examined the function of the tetratricopeptide repeat factor XAB2 in HR, since this factor has a conserved function in RNA processing. We have found that XAB2 is important for chromosomal double strand break (DSB) repair via two pathways of HR that require end resection as an intermediate step, end resection of camptothecin (Cpt) induced DNA damage, and RAD51 recruitment to ionizing radiation induced foci (IRIF). Furthermore, XAB2 mediates CtIP hyperphosphorylation induced by Cpt and BRCA1 IRIF, as well as histone acetylation events linked to HR proficiency. The capacity for XAB2 to promote HR correlates with its ability to form a complex with ISY1 and PRP19, which show a similar influence as XAB2 on HR. Our recent efforts include examining other members of the XAB2 complex, as well as the transcription unit aberrations caused by loss of this complex, which may contribute to the defects in HR.

Citation Format: David O. Onyango, Jeremy Stark. Defining the role of the XAB2 complex during homologous recombination [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 2472. doi:10.1158/1538-7445.AM2017-2472
Abstract 2485: Development and validation of Predi-HRD liquid biopsy test for PARP inhibitor clinical trials
Authors: Zhao Zhixin , Wiegers Toni , Cheung Tak , Du Pan , Jia Shidong
Published: July 2017

Response to DNA-damaging agents, such as platinum and recently emerged PARP inhibitors, is associated with homologous recombination deficiency (HRD) pathway. In fact, as reported by multiple clinical trials, patients with advanced breast, prostate, and ovarian cancers who have harmful mutations in BRCA1 and BRCA2 have demonstrated a great benefit from treatment of PARP inhibitors including olaparib, niraparib, and talazoparib. Current companion diagnostic assays that mainly examine germline defects from blood or somatic alterations from tumor tissues have shown several practical challenges: germline test does not capture somatic alterations of a tumor, initial biopsies from a tumor may not reflect the current status of the tumor’s genetic profile over time, and tissue biopsy may be of insufficient quantity or unavailable/unobtainable for downstream molecular profiling.

Here we introduce the Predi-HRD blood test, a non-invasive, next-generation sequencing (NGS)-based multiplex assay that enables real-time monitoring of temporal change of tumor heterogeneity and highly sensitive detection of defects in HR genes including BRCA1, BRCA2, ATM, CHEK2, among others. Technical validation was performed to evaluate assay sensitivity, specificity and accuracy using reference samples with known genetic profiling and further validated on a variety of orthogonal platforms such as digital PCR, allele-specific PCR and Sanger sequencing. Mutation prevalence of HR genes was examined in clinical plasma samples from patients with advanced ovarian cancer after systemic chemotherapy. The successful development of Predi-HRD liquid biopsy test offers an efficient solution to stratify and monitor cancer patients who may benefit from HRD-targeted therapeutics such as PARP inhibitors.

Citation Format: Zhixin Zhao, Toni Wiegers, Tak Cheung, Pan Du, Shidong Jia. Development and validation of Predi-HRD liquid biopsy test for PARP inhibitor clinical trials [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 2485. doi:10.1158/1538-7445.AM2017-2485
Abstract 2486: Tumor hypoxia induces DNA repair vulnerabilities through contextual loss of heterozygosity
Authors: Mahamud Osman , Chua Melvin , Lo Winnie , Zafarana Gaetano , Bristow Robert
Published: July 2017

Introduction: Intratumoural hypoxia leads to decreased expression in DNA damage response (DDR) and repair pathways. Given the ‘two-hit’ model for loss of gene function, we hypothesize that hypoxia-mediated down-regulation of gene expression and function, coupled with an already inactive allele contributes to an exploitable contextual ‘loss-of- heterozygosity’ phenotype.

Method: To interrogate this relationship, isogenic DLD-1 cells heterozygous and homozygous null for BRCA2, were placed under normoxic (21%) or hypoxic (0.2%) conditions for 72 hours. Hypoxia-mediated changes in DDR response and DNA repair were evaluated by cell proliferation, cell cycle analysis, western blots, qPCR, immunofluorescence, clonogenic assays and functional repair assays.

Results: No differences in proliferation and cell survival were observed between oxic and hypoxic cells (72 hours - 0.2% O2). Under chronic hypoxic conditions, confirmed by the up-regulation of VEGF and HIF1a, mRNA and protein expression of key homologous recombination (HR) genes (BRCA1, BRCA2, RAD51) were down-regulated. Functionally, BRCA2-/- null cells proved unable to recruit Rad51 foci and were profoundly sensitivity to PARP inhibition. Conversely, heterozygote BRCA2+/- cells retained the ability to recruit Rad51 foci under both oxic and hypoxic conditions. However, exposure to chronic hypoxia resulted in a reduction of foci formation. Chronically hypoxic BRCA2+/- cells exhibited a 30-40% increase in sensitivity to PARP inhibition compared to their oxic counterparts. Preliminary data shows a similar synthetically lethal relationship in genetic (BRCA2-/- ) and tumor microenvironment induced (BRCA2+/-) HR deficient cells, when challenged with DNA damage response (DDR) kinase inhibitors ATRi and DNAPKi.

Conclusions: Herein, we demonstrate a novel mechanism of contextual ‘loss-of heterozygosity’, which marries the tumour microenvironment and innate genetic alterations. The resultant increased sensitivity to DDR kinase inhibitors and PARPi highlights the therapeutic significance of this phenomenon.

Citation Format: Osman Mahamud, Melvin Chua, Winnie Lo, Gaetano Zafarana, Robert Bristow. Tumor hypoxia induces DNA repair vulnerabilities through contextual loss of heterozygosity [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 2486. doi:10.1158/1538-7445.AM2017-2486
Abstract 2489: Mre11-CDK2 interaction during the DNA double-strand break response
Authors: Morgan Mary J. , Festerling Todd A. , Buis Jeffrey , Ferguson David O.
Published: July 2017

The MRN (Mre11/Rad50/NBS1) complex is a group of highly conserved proteins central to the detection and repair of DNA double-strand breaks (DSBs). Inherited deficiencies in DNA DSB signaling result in a spectrum of disorders featuring cancer predisposition, neurodegeneration, and immunodeficiency. MRN directly binds DNA DSB ends and facilitates activation of ataxia-telangiectasia mutated (ATM) kinase, which initiates cellular responses including DNA repair, cell cycle checkpoints, and in some circumstances, apoptosis. Cellular responses to DNA DSBs require rapid communication between DNA repair complexes and the cell cycle machinery, but much about this relationship remains unclear. Our lab recently discovered an interaction between Mre11 and Cyclin-dependent kinase 2 (CDK2), a key component of the cell cycle machinery (Buis et al., NSMB, 2012). CDK2, when bound to its regulatory partner Cyclin A, promotes cell cycle progression through S phase. We demonstrated that the Mre11-CDK2/Cyclin A interaction is important in regulating the capacity for DNA repair by homologous recombination in normally dividing cells. Current work is focused on understanding the role of this interaction during DNA damage responses. We hypothesize that Mre11 interaction with CDK2 is a component of a molecular switch between the normal cell cycle and the DNA damage response. To test our hypothesis, we take advantage of murine alleles of Mre11 previously generated in the lab. We performed immunoprecipitation studies to investigate the protein-protein interaction in the presence of DNA damage. We also utilized kinase inhibitors to investigate the role of apical kinases in regulating the interaction. Finally, we are currently optimizing in vitro kinase assays to further understand a relationship between Mre11 and CDK2 enzymatic activity.Unpublished findings reveal that the Mre11-CDK2/Cyclin A interaction is altered upon DNA damage, a process which appears to be important for cell cycle checkpoint regulation. In conclusion, we demonstrate that the Mre11-CDK2 interaction plays important roles both in normally dividing cells and in the DNA damage response. Taken together, our data suggests that Mre11 may act to bridge the gap between DNA repair complexes and the cell cycle machinery.

Citation Format: Mary J. Morgan, Todd A. Festerling, Jeffrey Buis, David O. Ferguson. Mre11-CDK2 interaction during the DNA double-strand break response [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 2489. doi:10.1158/1538-7445.AM2017-2489
Abstract 2492: DNA polymerase beta participates in DNA end-joining
Authors: Ray Sreerupa , DeVeaux Michelle , Breuer Gregory , Bindra Ranjit , Zelterman Daniel , Sweasy Joann
Published: July 2017

DNA double strand breaks (DSBs) are one of the most deleterious lesions. If left unrepaired, DSBs lead to genomic instability and carcinogenesis. The cells combat DSBs by two classical pathways that include homologous recombination (HR) which requires the sister chromatid for sequence homology, and non-homologous end-joining (NHEJ), wherein the two DNA ends are re-joined. Recently a back-up NHEJ pathway has been reported and is referred non-canonical NHEJ which has been given many names, such as alternative NHEJ or microhomology-mediated end joining (MMEJ). The enzymatic mechanisms of non-canonical NHEJ are not well defined. NHEJ requires processing enzymes including nucleases and polymerases, although the roles of these enzymes in the pathway are poorly understood. Recent studies have implicated a role for DNA polymerase theta (Pol θ), an A-family polymerase is essential for non-canonical NHEJ pathway. Emerging evidence indicates X-family polymerases, mammalian DNA polymerases lambda (λ) and mu (μ) and yeast Pol 4 promote DNA end-joining. Our laboratory has recently provided evidence for a role for DNA polymerase beta (Pol β), another X-family polymerase, in V(D)J recombination, a process that requires end-joining. Here, using a recently developed fluorescence based assay that monitors non-canonical NHEJ and HR, we provide evidence that Pol β plays a role in the non-canonical NHEJ process. DNA sequencing at the break point junctions revealed Pol β-depleted cells have fewer small deletions than control cells, but significantly greater numbers of insertions and large deletions. We further demonstrate that Pol β-depleted cells have increased sensitivity to DNA damaging agents that induce double-strand breaks and that there is persistent accumulation of DSBs in these cells. In combination, our results suggest that Pol β is critical for double-strand break repair.

Citation Format: Sreerupa Ray, Michelle DeVeaux, Gregory Breuer, Ranjit Bindra, Daniel Zelterman, Joann Sweasy. DNA polymerase beta participates in DNA end-joining [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 2492. doi:10.1158/1538-7445.AM2017-2492
Abstract 2497: Differential requirement of amino acids on cell survival of ovarian cancer cells
Authors: Furusawa Akiko , Inoue Jun , Tsuda Hitoshi , Miyasaka Naoyuki , Inazawa Johji
Published: July 2017

Amino acids (AAs) are traditionally classified into nutritionally essential AAs (EAAs) or nonessential AAs (NEAAs) for animals and humans. Recent studies have demonstrated that not only EAAs but also NEAAs play important roles on energy metabolisms in cancer cells. However, which AAs are indispensable for human cancer cell survival has not been fully elucidated. The purposes of this study were 1) to determine the indispensable AAs for ovarian cancer (OVC) cells and 2) to investigate the relationship between the AAs synthetase and cancer cell survival.

Firstly, OVC cell lines were cultured with different medium in which each AA was depleted and cancer cell survival was examined. Among 17 OVC cell lines, EAAs were required in 12 cell lines, whereas others did not require EAAs for cell survival. Interestingly, cancer cell lines which required EAA also required at least one NEAAs, including arginine, cystine, glutamine, serine and tyrosine. Although extracellular glutamine has been known to be a critical factor for cancer cell survival and growth, 3 OVC cell lines did not require extracellular glutamine. Hence, we next examined glutamine synthetase (GS) gene, which is a critical enzyme for production of endogenous glutamine from glutamate. In OVC cell lines which did not require extracellular glutamine, GS expression level was positively correlated with cell survival rate under glutamine-depleted condition. Furthermore, we found that the expression of GS protein was negative in 38 of 645 primary OV tumors (5.9 %). Taken together, these results suggest that GS-down-regulated OVC cells require extracellular glutamine for their survival. Therefore, uptake inhibition of extracellular glutamine or reduction of extracellular glutamine level may be a novel therapeutic strategy for patients with ovarian cancer with “GS down-regulation”, as well as development of an AA-based precision medicine of OVC.

Citation Format: Akiko Furusawa, Jun Inoue, Hitoshi Tsuda, Naoyuki Miyasaka, Johji Inazawa. Differential requirement of amino acids on cell survival of ovarian 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 2497. doi:10.1158/1538-7445.AM2017-2497
Abstract 252: Resveratrol and pterostibene selectively chemosensitize Burkitt’s lymphoma cells to 5-Fluorouracil
Authors: Peck Connor J. , Townsend Michelle H. , O'Neill Kim L.
Published: July 2017

In the current study, we assess the chemosensitization activity of the naturally occurring polyphenols resveratrol (RES) and pterostilbene (PTER) to 5-Fluorouracil (5-FU) in Burkitt’s B-cell lymphoma. RES is a stilbenoid compound found in a variety of fruits, plants, and nuts. In addition to antioxidant and anti-aging properties, RES has been shown to exhibit significant anti-tumor activity against a variety of malignancies. Since the compound is typically protective of normal cells, its anti-cancer activity makes it a promising candidate as both a chemopreventative nutritional supplement and a chemotherapeutic agent. PTER, an analog of RES, has likewise shown anti-cancer activity. Its therapeutic potential, however, is much less understood. Recent studies have investigated the use of these and other natural compounds in adjuvant chemotherapy strategies, many of which continue to produce underwhelming rates of response. Here, we investigate the chemosensitization capacity of both RES and PTER to 5-FU, a commonly used drug in chemotherapy, in healthy lymphocytes and in Burkitt’s B-cell lymphoma (Raji) cells. MTS assays are used to measure the viability of malignant and normal lymphocytes after 5-FU treatment with or without co-incubation of RES, PTER, or RES/PTER combinations. We find that Raji co-incubation with physiologically relevant concentrations (<10uM) of either RES or PTER significantly increases 5-FU toxicity in Raji cells, with data suggesting PTER to be slightly more effective than RES. Interestingly, RES/PTER combinatorial treatments further increase chemosensitization, an important finding considering the typically low bioavailability of each individual compound in vivo. Together, these data support the potential use of RES as a chemosensitizing adjuvant and provide new evidence that its analog, PTER, also possesses significant chemosensitization capacity. Furthermore, our studies suggest that low physiological concentrations of PTER and RES may be still be sufficient to induce significant anti-cancer effects.

Citation Format: Connor J. Peck, Michelle H. Townsend, Kim L. O'Neill. Resveratrol and pterostibene selectively chemosensitize Burkitt’s lymphoma cells to 5-Fluorouracil [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 252. doi:10.1158/1538-7445.AM2017-252
Abstract 2521: Inhibition of metabolic reprogramming by zerumbone alters the tumorigenic potential of hepatocellular cancer
Authors: Wani Nissar A. , Zhang Bo , Teng Kun-yu , Barajas Juan , Ghoshal Kalpana , Brüschweiler Rafael , Jacob Samson T.
Published: July 2017

Incidence of hepatocellular carcinoma (HCC) that represents ~90% of all cases of primary liver cancer is on the rise worldwide. Sorafenib, the only approved targeted therapy, prolongs median survival only by ∼3 months. Thus, new therapeutic strategies are urgently needed. In this study, we investigated therapeutic potential of zerumbone, a sesquiterpene from an edible ginger, against HCC. Zerumbone inhibited proliferation and clonogenic survival of HCC cells by blocking glycolysis and pentose phosphate pathway, arresting cells at G2/M phase of cell cycle and inducing apoptosis. To uncover the underlying molecular mechanisms of its action on HCC cells, we employed several unbiased approaches. First, phosphokinase array showed significant inhibition PI3K/AKT/mTOR and STAT3 signaling in zerumbone-treated HCC cells. Gene Set Enrichment Analysis (GSEA) and Ingenuity Pathway Analysis (IPA) of the microarray data revealed that zerumbone-deregulated genes showed positive correlation with PI3/AKT/mTOR and STAT3 pathways and those involved in metabolism, apoptosis and cell cycle. Notably, the alteration in expression of genes regulated by PI3/AKT/mTOR or STAT3 pathways and downregulated by zerumbone in HCCs is associated with poor patient survival. These results implicate that treatment with this dietary sesquiterpene might lead to a better outcome in HCC patients. Indeed, zerumbone treatment significantly inhibited growth and lung metastasis of orthotopic HCC xenografts in NSG mice. These findings reveal novel therapeutic strategies targeting cancer metabolism. Collectively, these observations underscore the therapeutic potential of zerumbone in HCC.

Citation Format: Nissar A. Wani, Bo Zhang, Kun-yu Teng, Juan Barajas, Kalpana Ghoshal, Rafael Brüschweiler, Samson T. Jacob. Inhibition of metabolic reprogramming by zerumbone alters the tumorigenic potential of hepatocellular 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 2521. doi:10.1158/1538-7445.AM2017-2521
Abstract 2532: High expression of MiR-432-3p is associated with the chemoresistance by NRF2 stabilization via directly targeting KEAP1
Authors: Akdemir Burak , Inoue Jun , Kawano Tatsuyuki , Inazawa Johji
Published: July 2017

NF-E2-related factor 2 (NRF2) is a master transcriptional regulator that integrates cellular stress responses and is negatively regulated by Kelch-like ECH-associated protein 1 (KEAP1) at the post-translational level. In human cancers, aberrantly stabilized NRF2, either by mutation of NRF2 or KEAP1, plays a vital role in chemoresistance through the activation of target genes, suggesting that targeted inhibition of NRF2 is a potential therapy for NRF2-stabilized tumors. MicroRNAs (miRNA) are endogenous small noncoding RNAs that can negatively regulate gene expression by interfering with the translation or stability of target transcripts. Previously, we identified miRNAs negatively regulating NRF2 pathway via directly targeting NRF2 itself by a reporter-coupled miRNA library screening and demonstrated the potential of miRNA-based therapy against NRF2-stabilized tumors in esophageal squamous cell carcinoma (ESCC) (Mol. Cancer Res 2014, Cancer Res 2015).

In the present study, we further identified miR-432-3p as a miRNA positively regulating NRF2 pathway. MiR-432-3p could directly targeted KEAP1 via binding to its seed sequence within the cording region. Overexpression of miR-432-3p resulted in enhanced resistance to cisplatin via activation of NRF2 in ESCC cell lines. Furthermore, miR-432-3p was overexpressed in 55 of 84 primary ESCC tumors, compared with that of corresponding non-cancerous esophageal mucosa (65.5%). Importantly, we showed the negative correlation between the expression level of KEAP1 and miR-432-3p in primary ESCC tumors. Taken together, these findings suggest that the high expression of miR-432-3p may contribute to the chemoresistance by NRF2 stabilization via down-regulation of KEAP1 expression in ESCC.

Citation Format: Burak Akdemir, Jun Inoue, Tatsuyuki Kawano, Johji Inazawa. High expression of MiR-432-3p is associated with the chemoresistance by NRF2 stabilization via directly targeting KEAP1 [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 2532. doi:10.1158/1538-7445.AM2017-2532
Abstract 2538: MiR-638 promotes autophagy and malignant phenotypes of cancer cells via directly suppressing DACT3
Authors: Yang Ming
Published: July 2017

Dyregulation of autophagy is implicated in human cancers and the mechanism details remains largely unclear. Herein we report the regulatory role of miR-638 in autophagy of esophageal squamous cell carcinoma (ESCC) and breast cancer cells. We found that miR-638 overexpression promotes starvation- and rapamycin-induced autophagy. In ESCC and breast cancer cells, miR-638 acts as an oncogene and promote cell proliferation, migration, as well as invasion in vitro and in vivo. In accordance with this, we observed significantly higher miR-638 expression in ESCC and breast cancer tissues compared to normal tissues. To further elucidate regulatory mechanisms of miR-638 in autophagy, we performed a computational nomination of its target genes through intersecting the results of multiple prediction algorithms. DACT3, a key regulator of Wnt/β-catenin signaling, was predicted to be regulated by miR-638 by all programs and confirmed by experimental results. Depletion of DACT3 phenocopied effects of miR-638 overexpression, demonstrating its importance in autophagy. These results elucidate that the miR-638-DACT3 axis might be an important molecular pathway in controlling and autophagy and tumorigenesis. Our data in clinical tissue samples highlight miR-638 and DACT3 with histological marker for cancer detection and potentially therapeutic implications.

Citation Format: Ming Yang. MiR-638 promotes autophagy and malignant phenotypes of cancer cells via directly suppressing DACT3 [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 2538. doi:10.1158/1538-7445.AM2017-2538
Abstract 2539: MiR-96-5p functions as an oncogenic miRNA by inhibiting apoptosis in hepatocellular carcinoma
Authors: Iwai Naoto , Yasui Kohichiroh , Tomie Akira , Teasaki Kei , Kitaichi Tomoko , Dohi Osamu , Gen Yasuyuki , Ito Yoshito
Published: July 2017

Hepatocellular carcinoma (HCC) is one of the most aggressive cancers with high mortality worldwide. MicroRNAs (miRNAs) are small non-coding RNAs that have been used as cancer-related biomarkers and expected to be therapeutic agents. We performed genome-wide miRNA expression profiling of paired HCC tumors and non-tumorous liver tissues from patients with primary HCCs using the miRNA microarray (Agilent). We found that miR-96-5p was most significantly up-regulated in HCC tumors compared to non-tumor tissues. Although miR-96-5p is suggested to be an oncogenic miRNA, the function of miR-96-5p remains largely unknown. We identified the caspase-9 gene (CASP9) as a novel target of miR-96-5p, in addition to the forkhead box O1 gene (FOXO1) which is the known target of it. Caspase-9 protein is thought to play a central role in apoptosis and to be a tumor suppressor. Overexpression of miR-96-5p decreased caspase-9 protein expression and resulted in resistance to apoptosis induced by doxorubicin and UV in HCC cells. Our results suggested that miR-96-5p functions as an oncogenic miRNA by inhibiting apoptosis through decreasing caspase-9 expression in HCC.

Citation Format: Naoto Iwai, Kohichiroh Yasui, Akira Tomie, Kei Teasaki, Tomoko Kitaichi, Osamu Dohi, Yasuyuki Gen, Yoshito Ito. MiR-96-5p functions as an oncogenic miRNA by inhibiting apoptosis in hepatocellular 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 2539. doi:10.1158/1538-7445.AM2017-2539
Abstract 2540: miR-196b as a potential biomarker for human esophageal cancer
Authors: Tan Xiaohui , Chen Tao , Siegel Robert , Fu Sidney
Published: July 2017

Esophageal cancer is the sixth most common cause of cancer related death. Although multiple genetic and epigenetic alterations have been detected in esophageal cancer, molecular markers for early diagnosis and prediction of prognosis or treatment responses are quite limited. microRNA (miRNA) is a class of small-regulatory non-coding RNA, acting as either a tumor suppressor or oncogene by regulating gene expression through pairing with complementary seed of the targeted messenger RNAs (mRNA). A number of miRNA expression profiling studies have been conducted in esophageal. In our current study, we analyzed the most recent studies on miRNAs expression profiles in esophageal cancer. Consistently dysregulated miRNAs have been identified in esophageal cancer, including upregulation of miR-196b, miR-135a, and downregulation of miR-141, miR-200a-5p, miR-200b-3p, miR-27b, miR-210. We first assessed expression of miRNAs in esophageal cancer cell lines and primary esophageal cancer tissues by real-time reverse transcriptase-polymerase chain reaction (qRT-PCR). Significantly overexpressed miR-196b was observed in human esophageal squamous cell carcinoma KYSE-70 and KYSE-180 compared with normal esophageal squamous cell line, HET-1A. Furthermore, overexpression of miR-196b was detected in 12 out of 14 (86%) cancer tissues compared to the matched normal tissues. Forced expression of miR-196b promotes the proliferation and invasion in esophageal cancer cell lines. TargetScanS and miRanda were used to identify the target genes of miR-196b. A list of targets genes were predicted, including GATA6, ARHGAP28, EPS15 and EPHA7. Forced expression of miR-196b resulted in significant downregulated EPS15 and EPHA7 expression in esophageal cancer cell lines. Our present work suggested that miR-196b acts as an oncomiR by regulating EPS15 and EPHA7. Therefore, miR-196b could be used as a biomarker for esophageal cancer.

Citation Format: Xiaohui Tan, Tao Chen, Robert Siegel, Sidney Fu. miR-196b as a potential biomarker for human esophageal 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 2540. doi:10.1158/1538-7445.AM2017-2540
Abstract 2541: Two miR-34 loci, miR-34a and miR-34b/c, have differential anticancer effects in lung adenocarcinomas
Authors: Kim Jeong Seon , Ahn Young-Ho
Published: July 2017

Three miR-34 family members (miR-34a, miR-34b, and miR-34c) are clustered on two different chromosomal loci, miR-34a and miR-34b/c, and have identical seed-sequences predicted to target the same set of genes; however, miR-34a and miR-34c have different sets of negatively correlated genes in TCGA data of human lung adenocarcinomas. Therefore, we hypothesized that miR-34 family members, which are tumor suppressive miRNAs, might have differential effects on lung tumorigenesis. To prove this, we overexpressed each miR-34 cluster, miR-34a and miR-34b/c, in murine lung cancer cells. miR-34b/c enhanced cancer cell attachment and suppressed cell growth and invasion compared with miR-34a. In a syngeneic mouse model, both miR-34a and miR-34b/c blocked lung metastasis; whereas, miR-34b/c suppressed tumor growth more than miR-34a. miR-34b/c also decreased mesenchymal markers (Cdh2 and Fn1), and increased epithelial markers (Inadl, Crb3, Ocln, and Dsp) and miR-200 family members better than miR-34a, implying that miR-34b and miR-34c partially inhibit EMT. Furthermore, miR-34b and miR-34c are better prognostic markers than miR-34a in human lung adenocarcinoma patients. Collectively, we suggest that miR-34b and miR-34c are more effective tumor suppressors than miR-34a.

Citation Format: Jeong Seon Kim, Young-Ho Ahn. Two miR-34 loci, miR-34a and miR-34b/c, have differential anticancer effects in lung adenocarcinomas [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 2541. doi:10.1158/1538-7445.AM2017-2541
Abstract 2542: MSI2 binds LncRNAs and promotes self-renewal and oncogenesis through MYC expression
Authors: Siddique Hifzur , Narayan Padmani , Punj Vasu , Feldman Douglas E. , Machida Keigo
Published: July 2017

Backgrounds and Aims: RNA-binding protein MSI2 is elevated in several cancers and is linked to poor prognosis. Here, we sought to elucidate the role of MSI2 in regulating the expression of proto-oncogenes or tumor suppressor genes in hepatocellular carcinoma (HCC).

Methods: We performed RIP-seq using anti-MSI2 antibody in tumor-initiating stem-like cells (TICs) and subsequent validation by qPCR analysis.

Results: Among the MSI2-bound RNAs, MYC mRNA and long noncoding RNA (LncRNA) miR22 host gene (MIR22HG) and MARAT1 were identified by RIP-qPCR analysis. MSI2-MARAT1 binding dereppresses polycomb reppressor to recruit E2F1 in MYC promoter regions. It is known that the 5’-untranslated region of MYC contains an internal ribosome entry sequence (IRES) which allows IRES-dependent translation initiation along with canonical cap-dependent mechanisms. Our data show that MSI2 acts as an IRES trans-acting factors for MYC mRNA translation. MSI2 does not have any effect on the steady state level of MYC mRNA but significantly increases MYC protein levels, indicating that MSI2 regulates MYC at the post-transcriptional level. Further, we observed that MSI2 reduced the level of mature miR22 derived from MIR22HG processing. We showed that miR22 suppresses the expression of MYC thorough a 3’-UTR dependent process. Overexpression of MSI2 promotes TIC self-renewal and tumor initiation property in xenograft tumor mouse models, whereas silencing MSI2 reduces this occurrence.

Conclusion: we demonstrate that MSI2 promotes liver tumorigenesis by maintenance of MYC expression through dereppression of polycomb repressor and an IRES-dependent translation mechanism and possibly by inhibition of miR22 processing. Thus, MSI2 may be a useful prognostic factor for HCC and MSI2 targeted therapy and thus may be beneficial in the treatment of HCC patients.

Citation Format: Hifzur Siddique, Padmani Narayan, Vasu Punj, Douglas E. Feldman, Keigo Machida. MSI2 binds LncRNAs and promotes self-renewal and oncogenesis through MYC 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 2542. doi:10.1158/1538-7445.AM2017-2542
Abstract 2547: Discovery and characterization of late-stage breast cancer estrogen receptor alpha 1 bound long non-coding RNAs
Authors: Silva-Fisher Jessica Monique , Eteleeb Abdallah M. , Nielsen Torsten , Perou Charles M. , Reis-Filho Jorge S. , Ellis Mathew J. , Mardis Elaine R. , Maher Christopher A.
Published: July 2017

Breast cancer (BC) is the second most common newly diagnosed cancer and the second leading cause of cancer death among women in the United States. Despite the proven benefits of adjuvant endocrine therapy in women with hormone receptor positive BC, relapses still occur even after initial treatment with endocrine therapy for 5 years, referred to as late-stage relapse. Long non-coding RNAs (lncRNAs) have been shown to be dysregulated in breast cancer. Recent studies have also shown lncRNAs to function by interfacing with corresponding RNA binding proteins to play critical regulatory roles of diverse cellular processes. Therefore, we hypothesize that lncRNAs may interact with ER to regulate genes promoting late-stage relapse. To address this, we aimed to identify lncRNAs bound to the estrogen receptor alpha 1 protein (ESR1) that promote late-stage relapse breast cancer. We first used transcriptome sequencing to identify altered expression levels of lncRNAs between 72 primary tumors and 24 late-stage relapse breast cancer patients. We detected 1192 altered lncRNAs when comparing the metastatic to the primary samples (FDR <0.05). Next, to identify ESR1 bound lncRNAs associated with late-stage BC, we conducted RNA Immunoprecipitation Sequencing of all transcripts bound to ESR1 as compared to an IgG control in the ER+ T47D cell line. We identified 217 lncRNAs bound to ESR1 of which 50 were up-regulated in late-stage BC, termed Late-Stage Relapse BC ESR1-bound lncRNAs (LASERs). Next, we focused on characterizing the most up-regulated differentially expressed lncRNA, LASER1. We found that LASER1 has increased expression in ER+ breast cancer cell lines. Further, elevated expression of LASER1 was also detected in MCF7 long-term estrogen deprived cells lines that have amplified ER+, suggesting an ER dependent mechanism. Preliminary functional studies indicate LASER1 to promote proliferation and invasion in BC cell lines. Ongoing studies will decipher how LASERs interact with ESR1 to promote late-stage relapse. Overall, this is the first study to discover ESR1 bound lncRNAs that may be contributing to late-stage relapse in BC patients.

Citation Format: Jessica Monique Silva-Fisher, Abdallah M. Eteleeb, Torsten Nielsen, Charles M. Perou, Jorge S. Reis-Filho, Mathew J. Ellis, Elaine R. Mardis, Christopher A. Maher. Discovery and characterization of late-stage breast cancer estrogen receptor alpha 1 bound long non-coding RNAs [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 2547. doi:10.1158/1538-7445.AM2017-2547
Abstract 2553: High-density array-CGH with targeted NGS unmask multiple non-contiguous minute deletions on chromosome 3p21 in mesothelioma
Authors: Carbone Michele , Yoshikawa Yoshie , Emi Mitsuru , Hashimoto-Tamaoki Tomoko , Ohmuraya Masaki , Sato Ayuko , Tsujimura Tohru , Hasegawa Seiki , Nakano Takashi , Nasu Masaki , Pastorino Sandra , Szymiczek Agata , Bononi Angela , Pass Harvey I. , Yang Haining
Published: July 2017

We used a custom-made comparative genomic hybridization-array (aCGH; average probe interval 254 bp) to screen 33 malignant mesothelioma (MM) biopsies for somatic copy number loss throughout the 3p21 region (10.7 Mb) that harbors 251 genes, including BRCA1-associated protein 1 (BAP1), the most commonly mutated gene in MM. We identified frequent minute biallelic deletions (<3 Kb) in 46/251 genes: four were cancer associated genes: SETD2 (7/33), BAP1 (8/33), PBRM1 (3/33) and SMARCC1 (2/33). These four genes were further investigated by targeted Next Generation Sequencing (tNGS), which revealed sequence-level mutations causing biallelic inactivation. Combined high-density aCGH and tNGS revealed biallelic gene inactivation in SETD2 (9/33, 27%), BAP1 (16/33, 48%), PBRM1 (5/33, 15%) and SMARCC1 (2/33, 6%). The incidence of genetic alterations detected is much higher than reported in the literature because minute deletions are not detected by NGS or commercial aCGH. Many of these minute deletions were not contiguous but rather they alternated with segments showing oscillating copy number changes along the 3p21 region. Functional assays revealed that SETD2, PBRM1 and SMARCC1 act as tumor suppressor in MM. In summary, we found that in MM: 1) multiple minute simultaneous biallelic deletions are frequent in chromosome 3p21, where they occur as distinct events involving multiple genes; 2) in addition to BAP1, mutations of SETD2, PBRM1 and SMARCC1 are frequent in MM; 3) our results suggest that high-density aCGH combined with tNGS provide a more precise estimate of the frequency and types of genes inactivated in human cancer, than approaches based exclusively on NGS strategy.

Citation Format: Michele Carbone, Yoshie Yoshikawa, Mitsuru Emi, Tomoko Hashimoto-Tamaoki, Masaki Ohmuraya, Ayuko Sato, Tohru Tsujimura, Seiki Hasegawa, Takashi Nakano, Masaki Nasu, Sandra Pastorino, Agata Szymiczek, Angela Bononi, Harvey I. Pass, Haining Yang. High-density array-CGH with targeted NGS unmask multiple non-contiguous minute deletions on chromosome 3p21 in mesothelioma [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 2553. doi:10.1158/1538-7445.AM2017-2553
Abstract 2567: CYP24A1-induced vitamin D insufficiency promotes breast cancer growth
Authors: Osanai Makoto , Takasawa Akira , Takasawa Kumi , Murata Masaki , Sawada Norimasa
Published: July 2017

Vitamin D plays a critical role in the maintenance of tissue homeostasis by regulating the expression of genes affecting cell proliferation, differentiation, and apoptosis. The vitamin D 24-hydroxylase CYP24A1 functions in vitamin D target tissues to degrade the hormonal form of vitamin D. Existing knowledge regarding dysregulated CYP24A1 expression supports its candidacy as a putative oncogene. In our presentation, we demonstrate that the suppression of constitutive CYP24A1 expression by CYP24A1-specidic shRNA conferred target cells with increased susceptibility to apoptosis and consequently inhibited anchorage-independent growth in breast carcinoma cells. In addition, suppression of vitamin D metabolism following knockdown of CYP24A1 significantly reduced tumor growth in vivo. Since these data provide substantial evidence for a pro-survival and stimulatory oncogenic effect of CYP24A1 in breast carcinoma cells, we will discuss the potential feasibility of CYP24A1-inhibitory cancer therapies.

Citation Format: Makoto Osanai, Akira Takasawa, Kumi Takasawa, Masaki Murata, Norimasa Sawada. CYP24A1-induced vitamin D insufficiency promotes breast 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 2567. doi:10.1158/1538-7445.AM2017-2567
Abstract 256A: Validation of methyl donors between two food measurements in a colorectal cancer study
Authors: Young Lufei , Shiao S. Pamela K.
Published: July 2017

Purpose: The purpose of this study was to validate methyl donor intakes between 30-day food frequency questionnaire (FFQ) and 24-hour food record (FR) in a colorectal cancer study.

Background: Dietary methyl donors play pivotal roles in cancer prevention by promoting adequate metabolism and DNA methylation. The FFQ and 24-hour FR are the most commonly used methods to assess adequate nutrient intake, including methyl donors and other vital micronutrients that are essential to promote metabolism and methylation. While FFQ provides best estimates in dietary intakes, a 24-hour food record is less time consuming for subject burden.

Methods: A total of 134 participants’ dietary data were collected using FFQ and 24-hour FR by using US Department of Agriculture computerized programs. Bland and Altman methodology was used to validate the bias and agreement between these two measurements.

Results: Overall, the 24-hour measurements presented underestimated values across all nutrients in comparison to FFQ measurements. Using a 10% criterion on the differences between the two measurements, the percentage bias for 24-hour FR compared to 30-day FFQ was acceptable for most B vitamins, including B1 (-6.9 ±0.15), B2 (-8.66± 0.12), B3 (-9.25± 0.12), B6 (-5.02, ± 0.14), and B9 (folate: -7.90 ±0.24). However, the bias was greater for protein based methyl donors, including B12 (-17.23± 0.14), choline (-13.38± 0.11), Glycine (-17.53± 0.10), and Methionine (-18.88± 0.09). The correlations between the two measurements on all methyl donors ranged from 0.92 to 0.99. The precisions for all measurements based on the standard error (SE) were less than and within 0.03% (0.007 -0.021%). And, the agreements between the two measurements were less than and within 10% for Glycine and methionine (8.96 - 9.58%), based on the standard deviation (SD); however, greater than 10% for other protein based methyl donors including choline and other B vitamins (10.5-24.11%).

Conclusion: Proper dietary intakes of methyl donors are vital for cancer prevention. These findings point out the importance of further validation and use of more accurate food measurement to monitor dietary intake, and the interpretation of nutrient reports with caution.

Citation Format: Lufei Young, S. Pamela K. Shiao. Validation of methyl donors between two food measurements in a colorectal cancer study [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 256A. doi:10.1158/1538-7445.AM2017-256A