bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 446: Differential effects of folate depletion on metabolic reprogramming and oxidative stress in nonmetastatic and metastatic claudin-low breast cancer cells
Authors: Chen Xuewen , O'Flanagan Ciara H. , Hursting Stephen D. 
Published: July 2017

Abstract
Folate coenzymes play an important role in biosynthesis and methylation reactions. Aberrant folate metabolism has been implicated in the development of several cancer types, though mechanisms underlying folate metabolism and cancer development remain unclear. We previously showed that a folate-restricted diet can exert differential effects on metastatic versus nonmetastatic murine claudin-low breast cancer cells in vivo. Specifically, folate restriction increased growth and invasion of orthotopically transplanted M-Wnt (nonmetastatic) tumor cells, but decreased growth and lung metastases of transplanted metM-Wnt cells, a metastatic subclone of M-Wnt cells. The current study set out to explore the underlying mechanism. To examine the effect of long-term folate depletion (LFD) on M-Wnt and metM-Wnt cell metabolism, oxidative stress and autophagic flux in vitro, the two cell lines were grown in standard and folate-depleted media for 14 days. metM-Wnt cells showed higher oxidative stress, as measured by ROS staining and Nrf2 expression, and phosphorylation of the key nutrient sensor, AMPK, compared to M-Wnt cells when grown in standard growth medium. LFD M-Wnt cells showed an increased dependence on glycolysis compared to those cultured in standard medium. Both M-Wnt and metM-Wnt cells displayed a high autophagy level in LFD, measured by LC3B cleavage, and AMPK phosphorylation. However, LFD metM-Wnt cells showed low viability, increased apoptosis and loss of redox defense, as measured by cleaved-caspase 3 and Nrf2 expressions. These results suggest that non-metastatic M-Wnt cells undergo metabolic reprogramming, including a shift from oxidative phosphorylation to glycolysis that may fuel cell growth and proliferation. Further, an elevated autophagic flux may mitigate nutrient stress induced by folate depletion, which allows them to withstand LFD and which may contribute to a more invasive primary tumor in response to folate restriction. In contrast, metM-Wnt cells are unable to undergo this metabolic adaptation, and display increased oxidative stress and cell death in response to LFD, preventing the development of metastatic lesions in vitro. This study highlights different responses of primary and metastatic breast cancer cells to folate depletion. The results provide additional rationale for targeting folate metabolism as a potential strategy for treating metastatic breast cancer.
Citation Format: Xuewen Chen, Ciara H. O'Flanagan, Stephen D. Hursting. Differential effects of folate depletion on metabolic reprogramming and oxidative stress in nonmetastatic and metastatic claudin-low breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 446. doi:10.1158/1538-7445.AM2017-446
Abstract 4461: Detection of somatic mutations in exosomal RNA from human oral squamous cell carcinoma cells
Authors: Tokuzen Norihiko , Nakashiro Koh-ichi , Hamakawa Hiroyuki 
Published: July 2017

Abstract
Exosomes are small vesicles, ranging from 30 to 100 nm in size, secreted from most types of cells. They contain proteins, lipids, and nucleic acids (e.g. DNA, mRNA, and microRNA) and are thought to play an important role in cell proliferation, invasion, and metastasis in human malignancies. Recently, circulating exosomes have also been of interest as a source for liquid biopsies. In this study, we examined the usefulness of exosomal RNA as a biomarker and attempted to detect the tumor-specific gene mutations from exosomal RNA derived from human oral squamous cell carcinoma (OSCC) cells. We used 3 human OSCC cells (HSC2, KT-T, KT-N). KT-T and KT-N cells were established from the lower gingival tumor and lymph node metastasis, respectively. First, we detected the somatic mutations in genomic DNA extracted from these cells by next-generation sequencing (NGS) with the use of HaloPlex Cancer Research Panel (Agilent Technologies). PIK3CA H1047R mutation was identified in all OSCC cells, and KT-N cells had the additional HRAS Q61R mutation. We confirmed these mutations of PIK3CA and HRAS in OSCC cells by TaqMan® SNP Genotyping Assays (Thermo Fisher Scientific). Subsequently, we evaluated the gene mutations in exosomal RNA from these OSCC cells. Exosomal RNA was isolated from the conditioned medium using exoRNeasy Serum/Plasma Maxi Kit (Qiagen) according to the manufacture’s protocol. In exosomal RNA, we found the PIK3CA H1047R mutation from all OSCC cells and HRAS Q61R mutation from KT-N cells by genotyping assays. Furthermore, we assessed the detection of these mutations in tumor xenograft mouse models. KT-T and KT-N cells (5 x 106) complexed with Matrigel® (BD) in 100-µl aliquots were injected subcutaneously space in the flank of male athymic nude mice. Exosomal RNA was isolated from the serum of tumor-bearing nude mice using exoRNeasy Serum/Plasma Midi Kit (Qiagen). By genotyping assays using serum exosomal RNA, PIK3CA H1047R mutation was observed in both types of xenograft mice and HRAS Q61R mutation was positive in KT-N xenograft mice. Cancer cell-derived exosomal RNA had the same gene mutations in those cells, and could be detected in the serum of tumor-bearing nude mice. These results suggest that exosomal RNA is useful for detecting somatic mutations in OSCC cells.
Citation Format: Norihiko Tokuzen, Koh-ichi Nakashiro, Hiroyuki Hamakawa. Detection of somatic mutations in exosomal RNA from human oral squamous cell carcinoma 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 4461. doi:10.1158/1538-7445.AM2017-4461
Abstract 4468: Oncogenic activation of the RNA binding protein AGO2 in hepatocellular carcinoma
Authors: Dang Hien T. , Knight Lucy , Pomyen Yotsawat , Wang Xin Wei 
Published: July 2017

Abstract
Global transcriptomic alterations of coding and non-coding RNAs are a ubiquitous feature of cancers including Hepatocellular carcinoma (HCC). Dysregulation of RNA-binding proteins (RBPs), key regulators of RNA processing such as RNA maturation and degradation, is one mechanism in which cancer cells select to promote tumorigenesis. RBPs are highly expressed in solid tumors and have been demonstrated to be drivers of carcinogenesis, however, the underlying mechanisms in which RBPs regulate the HCC transcriptome is unknown. We analysed genomic alterations amongst a family of more than 800 mRNA RBPs (mRBPs) in 1,225 clinical specimens from HCC patients and found that RBPs are significantly activated through gene amplification in a subset of tumors with poor prognosis, suggesting their potential oncogenic roles in HCC progression. Amongst the top candidates, Argonaute 2 (AGO2) was further characterized for its oncogenic role and effects on the HCC transcriptome. Elevated AGO2 mRNA expression was highly correlated with elevated somatic copy number alterations across five different cancer types including HCC. Moreover, AGO2 expression was associated with overall survival in two independent data sets (TCGA and the Liver Initiative Cancer), suggesting that AGO2 activation is oncogenic. While the activation of AGO2 induced an oncogenic phenotype, the abrogation of AGO2 in HCC cells significantly decreased cancer associated phenotypes such as cell proliferation, migration/invasion and tumorigenicity in vivo. Further analyses revealed that AGO2-associated genes were tumor-related, including c-Myc. Notably, c-Myc amplification was also found in AGO2 high HCC cells, suggesting an interplay between AGO2 and c-Myc. Our results demonstrate that oncogenic activation of AGO2 is a novel mechanism that may contribute to global transcriptome selective for the activation of c-Myc oncogenic. Our current work suggests that therapies focused on targeting AGO2 may be valuable for clinical treatment of many different tumors with activated c-Myc signalling, including HCC
Citation Format: Hien T. Dang, Lucy Knight, Yotsawat Pomyen, Xin Wei Wang. Oncogenic activation of the RNA binding protein AGO2 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 4468. doi:10.1158/1538-7445.AM2017-4468
Abstract 4481: Translation initiation factor DAP5 plays an essential role in translational control of breast cancer metastasis
Authors: Parra Columba de la , Alard Amandine , Ernlund Amanda , Schneider Robert J. 
Published: July 2017

Abstract
Metastasis is the cause of 90% of cancer-related deaths. Selective mRNA translation has been found to be crucial for breast cancer development, progression and metastasis; however, there is a poor biological and mechanistic understanding of the role of translation in these processes. Our work and others have pioneered an understanding of translational regulation in breast cancer. We have previously shown that overexpression of initiation factor eIF4GI in advanced breast cancer cells selectively increases the translation of mRNAs encoding survival, cell cycle inhibition, and DNA damage and repair proteins, among other DNA damage-protective mRNAs. eIF4G consists of three family members: eIF4GI, eIF4GII, and the poorly studied eIF4G homolog, DAP5, the subject of this study. DAP5 lacks the N-terminal domain for eIF4E and PABP binding. DAP5 is therefore suspected to promote eIF4E-independent or IRES-driven translation of mRNAs involved in cell stress and oncogenesis, but its role in metastasis hasn’t been investigated. We analyzed the NCI human tissue genome cancer atlas (TCGA) and found that higher DAP5 mRNA expression is strongly associated with estrogen receptor negative breast cancer metastasis with lower overall survival. We then engineered a highly metastatic breast cancer cell line MDA-MB-231TR to express dox-inducible shRNA to DAP5 or a non-silencing (NS) control. Tumors were developed in clinically relevant orthotopic mouse models, with and without DAP5 silencing by addition of dox to the drinking water. Remarkably, reduction of DAP5 expression by ~70% had no impact on primary tumor growth but fully eliminated metastasis to the lung. Genome-wide transcriptome and translatome analysis of DAP5 and in vivo ultraviolet-crosslinking and high-throughput sequencing (HITS-CLIP) identified specific mRNAs that interact directly with DAP5. A significant fraction of DAP5 mRNA targets are involved in cell death and survival, cell proliferation, cell mobility, DNA repair and translation initiation and do not have IRESs, suggesting a novel role for DAP5 in a non-classical translation initiation process upon cellular stress and metastasis. Our results suggest that the translation initiation factor DAP5 likely plays a critical role in breast cancer metastasis by a unique mechanism for metastasis-specific translation initiation and provides new concepts for therapeutic strategies involving translational regulation.
Citation Format: Columba de la Parra, Amandine Alard, Amanda Ernlund, Robert J. Schneider. Translation initiation factor DAP5 plays an essential role in translational control of breast cancer metastasis [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 4481. doi:10.1158/1538-7445.AM2017-4481
Abstract 4486: Redox regulation of the biosynthesis of mitronic tsmiR miR6855 in the basal like breast cancer cells
Authors: Misra Smita , Chaudhuri Gautam 
Published: July 2017

Abstract
Radiation and chemotherapeutic agents eradicate tumors by inducing irreparable DNA damage. However, cancer cells often develop resistance to therapy by manipulating the DNA repair machinery. Conversely, a dividing cell constantly exposed to environmental and endogenous DNA damaging agents can transform into a tumor due to incorrect repair. Therefore the expression level of DNA repair proteins is critical both for cancer therapy and tumorigenesis. Our preliminary studies implied a unique mechanism involving an miRNA miR-6855-3p that promotes the biosynthesis of the transcriptional regulator protein SPRDX5 which enhances the expression of the tumor suppressor protein BRCA2 leading to the genotoxin and radiation-resistance of aggressive SLUG-high basal-like breast cancer (BLBC) cells. The miRNA miR-6855-3p thus acts as a tumor suppressor miRNA (tsmiR). Interestingly, the gene for the miRNA miR-6855-3p is mitronic and is nested within the intron#13 of the USP20 gene which is a deubiquitinase. Thus, the transcription of miR-6855-3p gene is regulated through the USP20 gene promoter. We present evidence here that USP20 and miR-6855 gene transcriptions are up regulated by oxidative stress. Tert-butylhydroperoxide was used for oxidative stress. Under the oxidative stress conditions tested, NRF2 level and the levels of several NRF2-regulated proteins are increased, indicating activation of NRF2 in the stressed BLBC cells. Under the stress conditions the levels of USP20 and miR-6855-3p are increased significantly. Knockdown of NRF2 prevented stress-induced elevation of USP20 and miR-6855-3p RNA level in the BLBC cells indicating the involvement of NRF2 in this process. The binding of NRF2 to the USP20 gene promoter and its function were characterized by ChIP analysis, site-directed mutagenesis and using the promoter-luciferase reporter constructs. We conclude that the biosynthesis of the tsmiR miR-6855-3p in the BLBC cells is regulated by oxidative stress and involves NRF2. Since oxidative stress is a hallmark in the etiology and progression of metastatic breast cancer, understanding the redox regulation of a tsmiR that positively influences BRCA2 gene expression in the BLBC cells could be clinically significant. Supported in part by DOD-CDMRP IDEA Expansion Grant# BC103645 and NIH/NCI grant 1R21CA181920-01 to GC and 1U54RR026140 to SM.
Citation Format: Smita Misra, Gautam Chaudhuri. Redox regulation of the biosynthesis of mitronic tsmiR miR6855 in the basal like breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4486. doi:10.1158/1538-7445.AM2017-4486
Abstract 4494: Tumor suppressive role of ZFP36L1 by suppressing HIF1α and Cyclin D1 in bladder and breast cancer
Authors: Loh Xin Yi , Ding Ling Wen , Koeffler H. Phillip 
Published: July 2017

Abstract
AU-rich mRNAs are a class of mRNAs that contains AU-rich elements (AREs) motifs in their 3’UTR. The half-life and turnover of AU-rich mRNAs are tightly regulated by AREs-binding proteins, such as Zinc finger protein 36 C3H type-like 1 (ZFP36L1). ZFP36L1 is one of the RNA-binding proteins (RBPs), which consists of two tandemly repeated zinc finger motifs that specifically recognize AREs motifs and mediate mRNAs decay. However, our knowledge on role of ZFP36L1 in breast and bladder cancers and its downstream targets remains poorly elucidated. Here, we hypothesized that ZFP36L1 might degrade oncogenic mRNAs transcripts, thus leading to suppression of tumorigenesis. Our analysis of in silico data revealed that ZFP36L1 is significantly mutated or downregulated in a variety of cancers. The high proportion of inactivation mutation pattern as well as the Mutsig result suggest that it may act as an unappreciated tumor suppressor. Lower ZFP36L1 expression correlated with reduced survival in patients. Forced expression of ZFP36L1 markedly reduced cellular proliferation, invasiveness and migration in vitro, as well as tumor growth in vivo. In addition, microarray and RNA-seq data analysis showed that several important cancer-related candidates such as IL8 and HIF1α were significantly downregulated. Overexpression of ZFP36L1 reduced HIF1α mRNA and protein expression. Similarly, HIF1α forced expression also inhibited ZFP36L1 mRNA and protein, suggesting a feedback loop of HIF1α and ZFP36L1. Dual luciferase reporter assays and RNA Electro-mobility Shift Assay (REMSA) showed that only wild type ZFP36L1, but not different mutants of ZFP36L1, was able to bind directly and to degrade a HIF1α 3’UTR construct that contains AU-rich regions. Meanwhile, mRNA pull down assay demonstrated that ZFP36L1 protein recognized cell-cycle related transcripts. Overexpression of ZFP36L1 led to reduction of Cyclin D1 and phospho-Rb in protein expression. Furthermore, SILAC data unveiled interesting binding partners of ZFP36L1. Collectively, our findings propose that ZFP36L1 might have a critical tumor suppressive role in breast and bladder cancer by negatively regulating mRNA whose protein products cooperatively promote hypoxia and transition into S phase of cell cycle. Augmenting ZFP36L1 function might disable the cell cycle and proliferation of aggressive bladder tumors.
Citation Format: Xin Yi Loh, Ling Wen Ding, H. Phillip Koeffler. Tumor suppressive role of ZFP36L1 by suppressing HIF1α and Cyclin D1 in bladder and breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4494. doi:10.1158/1538-7445.AM2017-4494
Abstract 4495: Elucidating BCL11A’s function in triple negative breast cancer
Authors: Stevers Nicholas O. , Tinsley Samantha L. , Moody Rebecca , Lin Chang-Ching , Meagher Jennifer , Stuckey Jeanne A. , Lo Miao-Chia , Sun Duxin 
Published: July 2017

Abstract
It has been recently shown that the B-cell CLL/lymphoma 11A (BCL11A) transcription factor is highly expressed in triple-negative breast cancer (TNBC) and has critical functions in promoting tumor growth and mammary stem cell maintenance. Studies in our group have found that the first twelve amino acids (aa 1-12) of BCL11A are a conserved sequence that allows binding to retinoblastoma binding protein 4 (RBBP4). RBBP4, a histone binding protein, is involved in many epigenetic complexes, including the Polycomb repressive complex 2 (PRC2), the nucleosome remodeling and deacetylase (NuRD) complex, and SIN3A complex. Through these interactions BCL11A may exert transcriptional and epigenetic regulation.
Herein we investigate the importance of BCL11A’s interaction with RBBP4 and its function in TNBC. BCL11A-complex interactions were observed through pull-down experiments of TNBC cell lysate utilizing aa 2-16 of BCL11A and a scramble control sequence. Our results demonstrate that this 16-amino acid sequence is sufficient to bind to RBBP4 and pull down the PRC2, NuRD, and SIN3A complexes. Furthermore, the NuRD and Sin3a complexes pulled down by BCL11A aa 2-16 retained their functionality as observed through post pull-down histone deacetylase (HDAC) activity assays. These results indicate significantly higher HDAC activity in the wildtype sequence as compared to the scrambled sequence. To further investigate this interaction, protein crystallization was conducted, the results of which validate the binding between BCL11A and RBBP4. Additionally, a BCL11A peptide (aa 2-12) and a scramble control were transfected into the TNBC cell line SUM149. Analysis via flow cytometry shows a reduction of the ALDH+ cell population in the BCL11A peptide transfected cells versus scramble control. We are currently investigating the necessity of this 12-amino acid sequence in interactions with RBBP4, PRC2, NuRD and SIN3A via co-Immunoprecipitation experiments using an N-terminal truncated BCL11A protein (del 2-12). The effects of full-length BCL11A and del 2-12 on the ALDH+ cell population are also being examined. These experiments will further delineate this sequence’s importance in BCL11A-RBBP4 interactions.
Citation Format: Nicholas O. Stevers, Samantha L. Tinsley, Rebecca Moody, Chang-Ching Lin, Jennifer Meagher, Jeanne A. Stuckey, Miao-Chia Lo, Duxin Sun. Elucidating BCL11A’s function in triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4495. doi:10.1158/1538-7445.AM2017-4495
Abstract 4496: Dissecting cellular heterogeneity using single cell RNA sequencing in human lung tumors
Authors: Courtois Elise T. , Li Huipeng , Tan Yuliana , Tan Daniel , Prabhakar Shyam , Robson Paul 
Published: July 2017

Abstract
Intra-tumor heterogeneity is a key determinant of tumor biology, treatment response and patient survival. It is therefore essential to comprehensively characterize the phenotypes and interactions of the diverse cells within the tumor ecosystem. However, traditional molecular profiling studies have largely relied on bulk-tissue analysis, which obscures the signatures of distinct cell populations.
We present here an unbiased analysis of functional heterogeneity in NSCLC (Non Small Cell Lung Cancer) cancers (Lung Adenocarcinoma and Squamous Cell Carcinoma) and their microenvironment using RNA-seq profiling of unsorted single cells from 20 primary tumors and matched normal lung tissue (NL). Using a new clustering algorithm RCA (Reference Component Analysis), we identified the major cell types composing the normal lung tissue as well as the tumor ecosystem such as epithelial, fibroblast, endothelial and immune cells. Notably, we were able to identify resident alveolar macrophages, in tumor and normal tissue and their single-cell differential expression analysis revealed substantial differences in their gene expression. Similarly, we identified blood-vessel endothelial cells in matched normal and tumor tissue, and identified the differentially expressed genes in both cell types. Our unbiased approach allowed us to study the diversity of the epithelial malignant cells present in different tumors, highlighting the tumor and patient specific variability. Together, the unbiased study of the NSCLC at the single cell level by sc-RNAseq offers a powerful tool to provide insights into the transcriptomic variability within the key cellular players of the tumorigenesis.
Citation Format: Elise T. Courtois, Huipeng Li, Yuliana Tan, Daniel Tan, Shyam Prabhakar, Paul Robson. Dissecting cellular heterogeneity using single cell RNA sequencing in human lung 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 4496. doi:10.1158/1538-7445.AM2017-4496