bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 2547: TERT promoter mutations in B viral humanhepatocarcinogenesis
Authors: Kim Young-Joo , Yoo Jeong Eun , Jeon Youngsic , Chong Jae Uk , Choi Gi Hong , Song Dae-Geun , Jung Sang Hoon , Oh Bong-Kyeong , Park Young Nyun 
Published: August 2019

Abstract
Telomerase reverse transcriptase (TERT) promoter somatic mutations, related to telomerase activation, have been known to frequently occur at two hot spots located at -124 and -146 bp relative to the start codon in various cancers. In the present study, we investigated the occurrence and implications of the genetic alterations of the TERT promoter in B viral hepatocarcinogenesis. TERT promoter mutations, especially -124C&gt;T mutation, obviously enhanced TERT promoter activity in hepatocellular carcinoma (HCC) cell lines. We identified prospero homeobox protein 1 (PROX1) as a novel transcriptional activator for TERT gene through binding to the promoter regions containing two hot spots. PROX1 binding affinity was strong to the mutant TERT promoter harboring a consensus E-twenty six/ ternary complex factor (ETS/TCF) binding sequence (CCGGAA). The incidence of TERT promoter mutations gradually increased according to the progression of human B viral multistep hepaticarcinogenesis, which was found in 9.0% of low grade dysplastic nodules (LGDNs), 13.5% of high grade dysplastic nodules (HGDNs), 27.3% of early HCCs (eHCCs) and 28.4% of progressed HCCs (pHCCs). The occurrence of TERT promoter mutations correlated with lower levels of alpha-fetoprotein (AFP) (p=0.046) and a poor overall survival (p=0.012) in B viral HCC patients. On the contrary to in vitro data, TERT mRNA expression was lower in B viral HCCs with the mutant TERT promoter compared to those without. In addition, mRNA level of PROX1 was not correlated with that of TERT in B viral HCCs, in contrast that such correlation was evident in non-B viral HCCs. Interestingly, induction of stable HBx expression inhibited PROX1-mediated TERT expression in vitro study. In conclusion, our findings suggest that TERT promoter somatic mutations are early events in B viral human multistep hepatocarcinogeneis and HBx can induce a loss of PROX1 function as transcriptional activator for TERT expression.
Citation Format: Young-Joo Kim, Jeong Eun Yoo, Youngsic Jeon, Jae Uk Chong, Gi Hong Choi, Dae-Geun Song, Sang Hoon Jung, Bong-Kyeong Oh, Young Nyun Park. TERT promoter mutations in B viral humanhepatocarcinogenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2547.
Abstract 2548: DNA damage response gene expression in CHK1 inhibitor responsive and resistant mouse models of MYC driven B-cell lymphoma
Authors: Hannaway Nicola L. , Hunter Jill E. , Greystoke Alastair , Perkins Neil D. 
Published: August 2019

Abstract
Enhanced tumor replication stress and genomic instability can lead to disruption of the DNA damage response, leading to tumor survival and dependence on essential checkpoint controls. Drugs to target intact pathways, such as CHK1 inhibitors, are therefore desirable and currently in clinical trials as potential future anticancer therapies. The underlying mechanisms underpinning the response and resistance to CHK1 inhibitor treatment are still unclear. We have demonstrated that NF-κB can regulate the response to oncogene induced DNA replication stress in vivo through regulation of CLSPN (Claspin) gene expression. Claspin is an essential adaptor protein required for the phosphorylation and activation of CHK1 by ATR. Using the Eµ-MYC mouse model of B-cell lymphoma we have found that mutation of NF-κB subunits (knockout of c-Rel or a T505A transactivation domain mutation of RelA) leads to earlier lymphoma onset that correlates with loss of Clspnexpression and inhibition of CHK1 activity. Moreover, while wild type Eµ-MYC lymphomas are highly responsive to CHK1 inhibitor treatment, by contrast Eµ-MYC NF-κB mutant cRel-/- or RelAT505A lymphomas are resistant. To understand more about how MYC driven lymphoma cells respond to CHK1 inhibitor treatment, we have investigated changes in the expression of genes encoding members of DNA damage response pathways. Wild type mice reimplanted with Eµ-MYC lymphoma cells were treated with the CHK1 inhibitor CCT244747 and harvested at multiple fixed timepoints. Quantitative PCR analysis of mRNAs encoding proteins in the ATR/CHK1 and ATM/CHK2 pathways was performed, with RPL13A used as reference gene. Interestingly, while dramatic changes were seen in wild type Eµ-MYC cells, these were not seen in CHK1 inhibitor resistant cRel-/- lymphomas. We observed an upregulation of the DNA damage and cell cycle responsive genes in the CHK1 inhibitor sensitive wild-type Eµ-MYC mice. This is consistent with with previously published in vitro studies and suggests an S phase cell cycle arrest in response to CHK1 inhibitor induced DNA damage. This response, however, is absent in the CHK1 inhibitor resistant Eµ-MYC NF-κB mutant lymphomas. It is hoped that by understanding these differences in gene expression that biomarkers of CHK1 inhibitor response can be identified to help stratify future clinical candidates.
Citation Format: Nicola L. Hannaway, Jill E. Hunter, Alastair Greystoke, Neil D. Perkins. DNA damage response gene expression in CHK1 inhibitor responsive and resistant mouse models of MYC driven B-cell lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2548.
Abstract 2553: Integration of genomic studies and the patient-derived xenograft model in nasopharyngeal carcinoma precision medicine research
Authors: Hsu Cheng-Lung , Li Hsin-Pai 
Published: August 2019

Abstract
Patient-derived xenograft (PDX) tumor model has become a new approach to identify druggable tumor mutations, and to screen and evaluate personalized anti-cancer drugs. Here, we established five nasopharyngeal carcinoma (NPC) PDXs in mouse model and performed whole-exome sequencing (WES) and copy number variations (CNVs) analyses. Relatively high incident rate of CNV aberration in cell cycle pathway was detected. Among these five NPC-PDXs, three had cyclin D1 (CCND1) amplification while four had cyclin-dependent kinase inhibitor CDKN2A deletion. Selected inhibitors were tested for their anti-tumor effects in two NPC-PDX mouse models. Palbociclib, a cyclin-dependent kinase inhibitor, revealed efficient anti-tumor effects by inducing G1 arrest in the PDX tumor according to RNA sequencing. In this study, cyclin D1 overexpression was also observed in &gt;90% clinical metastatic NPC tumors (87/91) and was associated with poor outcomes. One NPC patient with liver metastatic who was prescribed with Palbociclib had stable disease and a drop in Epstein Barr virus (EBV) DNA titer. CNV analysis disclosed that plasma CCND1/CDKN2A ratio is correlated with EBV DNA load in NPC patients’ plasma and could serve as a screening test to select potential CDK4/6 inhibitors treatment candidates. Taken together, our findings indicate that integrated information from sequencing-based genomic studies and tumor transcriptomes before and after drug treatment in NPC-PDX models provide novel guidelines for personalized precision treatments.
Citation Format: Cheng-Lung Hsu, Hsin-Pai Li. Integration of genomic studies and the patient-derived xenograft model in nasopharyngeal carcinoma precision medicine research [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2553.
Abstract 2558: Regulation of the expression of the DNA repair endonuclease 8-like 3 gene in hepatocellular carcinoma
Authors: Huang Wenya 
Published: August 2019

Abstract
Hepatocellular carcinoma (HCC) is the fifth commonest malignancy in the world, but the molecular mechanism of HCC development is still unclear. Previous studies had showed that the endonuclease 8-like 3 (Neil3) gene, a DNA glycosylase for oxidative DNA repair, overexpressed in most of cancers including HCC. In our previous cDNA microarray analysis in HCC tissues, it was found that the Neil3 gene was highly expressed in mouse and human tumors. The results of real-time RT-PCR analysis in 113 HCC patients showed that the Neil3 gene mRNA was increased in most human tumors. The Neil3 gene expression levels were also highly correlated with HCC recurrence in the patients receiving the hepatectomy surgeries, suggesting that it can serve as a prognostic marker for HCC. In this study we characterized the molecular mechanisms of the Neil3 gene expression regulation in HCC. We analyzed the methylation status in the Neil3 gene promoter regions by DNA methylation array (Agilent) and found that the Neil3 gene promoter was hypo-methylated in HCC tumors. Also, by the promoter reporter assays it was found that the main regulatory region for its transcription activity was from -123 to +94 upstream to the transcription start site. Furthermore, the DNA affinity precipitation assay (DAPA) was performed to screen for the transcription factors that bind to the Neil3 promoter and identified that cell cycle regulator E2F1, Yin Yang 1 (YY1) and histone deacetylase 1 (HDAC1) bind to the Neil3 gene promoter. It suggested that E2F1, YY1 and HDAC1 play important roles in regulating Neil3 gene expression. These transcription factors have been known to enhance cell proliferation and potentially the NEIL3-mediated oncogenic properties. And treatments of the HDAC inhibitor SAHA increased the Neil3 mRNA and protein levels. The functional effects of these pro-oncogenic transcriptional factors to the NEIL3-relevant HCC progression are currently in investigation. The results of these studies will clarify the regulatory mechanisms for the Neil3 gene induction in HCC progression.
Citation Format: Wenya Huang. Regulation of the expression of the DNA repair endonuclease 8-like 3 gene in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2558.
Abstract 2559: Functional characterization of a RECQL4 mutation in Rothmund Thomson Syndrome
Authors: Wu Tianyi , Walker Robert L. , Pineda Marbin , Lee MiYoung , Zhu Yuelin , Venkitaraman Ashok R. , Meltzer Paul S. 
Published: August 2019

Abstract
Osteosarcoma (OS) is the most common malignancy of the bone, typically diagnosed during the adolescent years. Despite early advances in treatment, OS survival rates have not improved in recent times. Targeted treatment remains elusive because OS is a genetically complex and heterogeneous disease and the low incidence of sporadic OS presents a challenge in dissecting the causes and drivers of tumor development. Type II Rothmund-Thomson Syndrome (RTS), a cancer predisposition disorder, presents a potential model for studying OS pathogenesis as roughly 30% of Type II RTS patients are eventually diagnosed with OS. Type II RTS is associated with germline mutations of the DNA helicase RECQL4 that exclusively target the C-terminal helicase domain thought to be involved in various cellular mechanisms of DNA repair. The N-terminal SLD2-homology domain, required for the assembly of the CMG complex at origins of replication, is spared. We used CRISPR/Cas9 gene editing to generate cell lines containing a common RECQL4 mutation identified in Type II RTS patients to further study its effects. Unexpectedly, a mutation previously reported as a nonsense mutation instead upregulates the activation of a known cryptic splice site in exon 14. This splice variant results in the in-frame deletion of the final 66 amino acids of exon 14. Our cell lines exhibit a mildly increased sensitivity to the DNA double-strand break inducing agent neocarzinostatin consistent with RECQL4’s reported functions in DNA damage repair. We will use next generation sequencing techniques to further characterize DNA damage repair signatures in RTS RECQL4 mutant cell lines.
Citation Format: Tianyi Wu, Robert L. Walker, Marbin Pineda, MiYoung Lee, Yuelin Zhu, Ashok R. Venkitaraman, Paul S. Meltzer. Functional characterization of a RECQL4 mutation in Rothmund Thomson Syndrome [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2559.
Abstract 2573: DNA damaging drugs stimulate tRNA cleavage through SLFN11 to inhibit protein synthesis and induce cell death
Authors: Li Manqing , Kao Elaine , Malone Dane , Gao Xia , Wang Jean Y. , David Michael 
Published: August 2019

Abstract
DNA damaging agents (DDAs) based chemotherapies are the first and still the most widely used anticancer treatments. However, quickly developed drug resistance of cancer cells often impedes their efficacies. Two independent transcriptome analyses in vast collections of cancer cell lines discovered that human SLFN11 is the only gene whose expression significantly sensitizes cancer cells to DNA damaging agents (DDAs) including Top1 and Top2 inhibitors, DNA alkylating agents, and DNA synthesis inhibitors. But the mechanism was unclear. We showed previously that SLFN11 inhibits HIV viral proteins syntheses by modulating tRNAs abundances and exploiting the biased codon usage of the virus. We hereby report that upon DDAs treatment, SLFN11 preferentially inhibits translation of genes involved in DNA damage response and repair, including ATR and ATM, based on their distinct codon usages, while the early DNA damage response signaling remains unaffected. Type II tRNAs, which include all serine and leucine tRNAs, are cleaved in a SLFN11-dependent manner in response to DDAs. The syntheses of proteins encoded by genes with high TTA (Leu) codon usage such as ATR display utmost susceptibility to SLFN11 expression due to the extreme low abundance of cognate tRNA-Leu-TAA. Specific inhibition of tRNA-Leu-TAA expression with special antisense oligonucleotides (Gapmers) suppressed ATR protein expression and restored DDA sensitivity of SLFN11-deficient cancer cells. Our study uncovered a novel mechanism of DNA damage response regulation mediated by SLFN11-dependent tRNA cleavage and codon-specific translational inhibition. Further investigation will elucidate the roles of SLFN11 in DNA damage-related tumorigenesis. More importantly, bioinformatics analysis revealed high frequency of codon TTA (Leu) usage in most genes involved in DNA damage response signaling and repair mechanisms including Homology Directed Repair (HDR), Nonhomologous End-Joining (NHEJ), and Mismatch Mediated Repair (MMR). Instead of targeting single gene product, novel therapies based on the modulation of tRNA-Leu-TAA expression would effect by inhibiting the protein synthesis of a wide spectrum of genes involved in DNA damage response and repair, thus preventing the development of drug resistance by cancer cells.
Citation Format: Manqing Li, Elaine Kao, Dane Malone, Xia Gao, Jean Y. Wang, Michael David. DNA damaging drugs stimulate tRNA cleavage through SLFN11 to inhibit protein synthesis and induce cell death [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2573.
Abstract 2575: EZH2 mediates resistance to cisplatin in small cell lung cancer through nucleotide excision repair
Authors: Koyen Allyson E. 
Published: August 2019

Abstract
Small cell lung cancer (SCLC) is the most aggressive form of lung cancer, with a five-year survival rate of 7%. Cisplatin-based chemotherapy is the first line treatment for SCLC; however, many patients develop treatment resistance and experience tumor recurrence. Targeting proteins critical to the repair of cisplatin DNA crosslinks is a strategy for overcoming acquired cisplatin resistance in SCLC, but many proteins that mediate crosslink repair have yet to be identified. To address this issue, we performed a synthetic lethal siRNA screen in cisplatin resistant SCLC cells, and identified EZH2 as one of the strongest mediators of cisplatin resistance. EZH2 localizes to sites of DNA damage which are induced by UVA-crosslinking laser microirradiation and interacts in a complex with DDB1, and DDB2, members of the nucleotide excision repair (NER) pathway. Loss of EZH2 sensitizes SCLC cells to UV damage, and further, loss of EZH2 and DDB1 together are epistatic in the sensitization of SCLC to cisplatin, confirming a role for EZH2 in NER. Specifically, EZH2 promotes the stability of DDB2, which is responsible for the detection NER lesions. This occurs independently of EZH2’s methyltransferase activity on H3K27. Finally, we found EZH2 expression correlates with cisplatin resistance across SCLC cell lines. Together, this data suggests that EZH2 functions as a novel regulator of NER, and that EZH2 is a promising target for cisplatin resistant SCLC.
Citation Format: Allyson E. Koyen. EZH2 mediates resistance to cisplatin in small cell lung cancer through nucleotide excision repair [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2575.
Abstract 2589: A systematic study on the anti-tumor effect of combinatorial miRNA expression in hepatocellular carcinoma
Authors: Xu Feng , Tong Man , Ma Stephanie , Wong Alan SL 
Published: August 2019

Abstract
Hepatocellular carcinoma (HCC) is the sixth most common cancer and the third leading cause of cancer mortality worldwide. Treatment options for HCC patients are limited, especially for those with advanced HCC. Deregulation of microRNA (miRNA) expression is frequently observed in HCC, and many cellular targets of miRNAs are genetic regulators of tumorigenesis. In addition, miRNAs interact with each other to coordinate targeted gene expressions. The potential of devising combinatorial miRNA-based therapies for HCC, however, remains largely unexplored. Here, we performed high-throughput CombiGEM screens to characterize the anti-tumorigenic effect of combinatorial miRNA expression. We assembled a library of 1,849 pairwise combinations for 43 human miRNAs that are downregulated in HCC patients/cell lines, and identified four miRNA combinations that exert anti-proliferative effect in HCC cells both in vitro and in vivo. Further experiments are underway to validate and characterize the anti-tumor effect of these newly identified miRNA combinations in HCC.
Citation Format: Feng Xu, Man Tong, Stephanie Ma, Alan SL Wong. A systematic study on the anti-tumor effect of combinatorial miRNA expression in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2589.
Abstract 259: Interplay between Bcl-2 and cFLIP in lymphoma disease progression is a function of an altered redox milieu
Authors: Hirpara Jayshree L. , Pervaiz Shazib 
Published: August 2019

Abstract
Bcl-2 is associated with chemoresistance and despite the preponderance of evidence linking its anti-apoptotic function to hematologic cancers, it’s now emerging that overexpression of Bcl-2 is a feature shared by a host of cancers. Canonically, the death inhibitory activity of Bcl-2 is associated with its ability to prevent mitochondrial outer membrane permeabilization. However, recent evidence has highlighted a novel facet in the biology of Bcl-2, whereby enforced expression of Bcl-2 resulted in an increase in mitochondrial oxygen consumption and elevated levels of the reactive oxygen species (ROS), superoxide (O2-.). Alleviating the levels of intracellular O2-. sensitized Bcl-2 overexpressing cells to death receptor induced apoptosis via a robust increase in upstream caspase 8 activation. Using a variety of functional mutants of the NOX-activating small GTPase Rac1, we show a clear link between Bcl-2 induced apoptosis resistance and intracellular O2-.. In the search for the molecular target of this inhibitory signal, we now show that Bcl-2 overexpression is associated with an increase in the transcription and protein levels of the receptor inhibitory protein, cFLIP. We employed pharmacological and genetic approaches to modulated intracellular O2-. and present evidence cFLIP is transcriptionally regulated by O2-.; increase in cFLIP promoter activity and mRNA levels. Interestingly, inhibiting glycolysis also resulted in downregulation of cFLIP in a ROS-dependent manner. Notably, primary cells derived from patients with lymphoma also showed a significant downregulation of cFLIP when subjected to conditions that decrease O2-. and elicited enhanced sensitivity to TRAIL-induced apoptosis. Importantly, TCGA and Affy meta-cohorts’ analyses revealed consistent correlation trend: Bcl-2 and cFLIP (CFLAR) were positively correlated; Bcl-2 and SOD1 (superoxide dismutase 1) were negatively correlated. A strong negative correlation was also observed between CFLAR and SOD1. Furthermore, Kaplan-Meier analyses of overall survival (OS) were performed in the in-house High expression of either Bcl-2 or CFLAR conferred poor OS outcome. When stratified by CFLAR and Bcl-2 expressions, cases with higher expression of the two genes had the worst prognosis with the shortest median survival. Notably, DLBCL with high Bcl-2 and low SOD1 had the worst OS outcome, compared against expression levels of Bcl-2 and SOD1. Together, these findings point to a concordance between cFLIP and Bcl-2, which negatively correlates with SOD1 in driving lymphoma progression.
Citation Format: Jayshree L. Hirpara, Shazib Pervaiz. Interplay between Bcl-2 and cFLIP in lymphoma disease progression is a function of an altered redox milieu [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 259.