bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 448: Expression of Galectins in high grade serous ovarian cancer
Authors: Labrie Marilyne , Communal Laudine , Vladoiu Maria-Claudia , Dupont Pascal , Mes-Masson Anne-Marie , St-Pierre Yves
Published: July 2016

Ovarian cancer (OC) is the 5th leading cause of cancer-related deaths in the Western world. Despite improvements in various treatments, the five-year survival of patients with advanced stage disease remains less than 40%. Approximately 70% of malignant OCs are attributed to the high-grade serous carcinoma (HGSC) histological subtype, which is typically treated by a surgical tumor debulking followed by platinum/taxane chemotherapy. Unfortunately, although approximately 80% of patients respond well to the initial chemotherapy treatment, a large portion of patients develop drug resistance during subsequent cycles of chemotherapy. The non-uniformity of response to therapy complicates the clinical decision-making process and reflects the genetic complexity that gives rise to intra-tumor heterogeneity. Clearly, there is an urgent need to develop reliable clinical biomarkers to identify patients at different levels of risk for specific outcomes. Here, we have investigated the expression of galectins (gal) in HGSC and examined their potential as biomarkers. Galectins have been shown to play a dual role in cancer progression. When released in the extracellular space by cancer cells, they are particularly efficient in creating an immunosuppressive tumor microenvironment, both locally and systemically. Inside cancer cells, they provide cancer cells with increased resistance to apoptosis induced by chemotherapeutic agents. Using tissue microarrays constructed from formalin fixed paraffin embedded tissues from 209 patients with HGSC, we have identified a new protein signature that takes into account the expression of galectins in both cancer and stromal cells. Our study showed that increased protein expression of stromal gal-1 and epithelial gal-8/9 in primary tumors was associated with a poor response to treatment in patients with HGSC. This signature also increased the predictive value of CA-125 on five-year disease-free survival, chemotherapy treatment response and five-year overall survival. Univariate and multivariate analyses revealed that gal-8 and gal-9 were both independent predictors of chemoresistance and overall survival, respectively. From a fundamental point of view, our project also contributes to better define the heterogeneity of the disease. Overall, these data provide a rational for further studies of Galectins in OC.

Citation Format: Marilyne Labrie, Laudine Communal, Maria-Claudia Vladoiu, Pascal Dupont, Anne-Marie Mes-Masson, Yves St-Pierre. Expression of Galectins in high grade serous ovarian cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 448.
Abstract 4481: Phosphorylation regulates EZH2 neoplastic functions in triple-negative breast cancer
Authors: Anwar Talha , Arellano-Garcia Caroline , Burman Boris , Kleer Celina G.
Published: July 2016

Background: Triple negative (estrogen receptor, progesterone receptor, HER2-neu negative) breast cancers (TNBC) comprise 15% of all breast cancers but are responsible for a disproportionately high number of deaths. Overexpression of the histone methyltransferase EZH2 (Enhancer of Zeste Homolog 2) is an independent prognostic biomarker significantly associated with poorly-differentiated TNBCs and poor patient outcome. We previously identified a novel link between EZH2 and the p38 mitogen-activated protein kinase, an important mediator of progression and metastasis of TNBC. We found that EZH2 binds to p38, and that EZH2 and activated p38 are concordantly expressed in the metastases of breast cancer patients. Based on these data and previous in vitro studies, we hypothesized that p38 MAPK may also regulate EZH2 through phosphorylation in breast cancer. We further hypothesized that this phosphorylation event may be important for EZH2 contribution to malignancy.

Methods: In order to test this hypothesis, we performed knockdown rescue experiments in triple-negative breast cancer cell lines MDA-MB-231 and MDA-MB-436. Stable knockdown of EZH2 was achieved using shRNA targeting the 3’UTR. Knockdown of EZH2 was rescued by reintroduction of myc-EZH2 (WT) or a T367A-EZH2 phosphorylation-deficient mutant. Cell lines were then used in functional assays of proliferation, migration, and invasion. In order to further interrogate the importance of this phosphorylation event, we developed a phospho-specific EZH2 T367 antibody.

Results: p38-mediated phosphorylation of EZH2 at T367 contributes to the migratory and invasive properties of TNBC. Mechanistically, phosphorylation by p38 does not affect binding to other PRC2 members but may affect EZH2 activity. We are currently investigating the relevance of pEZH2 as a biomarker of breast cancer survival with our new antibody.

Conclusions: We provide evidence that p38 phosphorylation of EZH2 at T367 contributes to malignancy of triple-negative breast cancers. Our data suggest a new mechanism by which EZH2 is regulated and may offer an additional mechanism by which EZH2 contributes to TNBC progression.

Citation Format: Talha Anwar, Caroline Arellano-Garcia, Boris Burman, Celina G. Kleer. Phosphorylation regulates EZH2 neoplastic functions in triple-negative breast cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4481.
Abstract 4492: Investigation of the germline mutational landscape of GBA in general cancer patients and its role in the tumorigenesis
Authors: Shin Junghoon , Kim Daeyoon , Koh Youngil , Yoon Sungsoo
Published: July 2016

Introduction

Gaucher disease (GD) is an autosomal recessive disease resulting from defective enzymatic activity of acid β-glucosidase (β-glucocerebrosidase). Approximately 400 point mutations in GBA, located in 1q21, have been described and genotype-phenotype correlation was revealed. Previous studies have shown the association of type 1 GD and development of various types of cancers. However, the mutational landscape of GBA and its clinical implication in general cancer patients have not been systematically explored.

Methods

We used publicly available data obtained from ICGC and TCGA data portal (sftp://dccsftp.nci.nih.gov) for the analysis of single nucleotide variants (SNVs) in GBA in general cancer patients. GenBank reference sequence NM_001005741 was used for SNP identification.

Results

A total of 2124 cancer patients comprising 29 cancer types were included. Mutations with allele frequency lower than 0.3 or coverage depth lower than 15 were filtered out from analysis. Overall, 7% (151 out of 2124) were GBA mutation carriers, including 1 nonsense (involving exon 1) and 153 missense mutations, including 5 homozygous alternate. The most frequently detected SNVs included rs2230288 (c.1093G>A:p.E365K, 3 homozygous alternate), rs75548401 (c.1223C>T:p.T408M), rs143187997 (c.58A>G:p.I20V, 1 homozygous alternate), rs150466109 (c.38A>G:p.K13R, 1 homozygous alternate), rs76763715 (c.A1226G:p.N409S), and rs421016 (c.1448T>C, p.L483P), accounting for 1.88%, 1.55%, 1.27%, 1.04%, 0.85%, and 0.28% of the entire cancer population, respectively. We compared our data with 1000 Genomes data of 2504 normal subjects (ftp://ftp.1000genomes.ebi.ac.uk/vol1/ftp/release/20130502), which revealed that the prevalence of rs2230288, rs75548401, and rs76763715 carriers was significantly higher in the cancer group than 1000 Genomes population (p = 0.01, <0.001, and <0.001 by chi-square test, respectively). Regarding somatic mutational profile of tumor samples of 151 germline GBA mutation carriers, the most frequently mutated genes included TP53, PIK3CA, and KRAS, accounting for 28.5%, 7.9%, and 7.9%, respectively.

Conclusion

Although overall prevalence of germline GBA mutation carriers was not significantly different between cancer patients and general population collected from 1000 Genomes data, SNVs in some specific positions showed statistically significant difference in prevalence between 2 groups, implying association between specific mutational loci of GBA and cancer-developing mechanism, even in heterozygous carriers.

Citation Format: Junghoon Shin, Daeyoon Kim, Youngil Koh, Sungsoo Yoon. Investigation of the germline mutational landscape of GBA in general cancer patients and its role in the tumorigenesis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4492.
Abstract 4506: Identification of druggable transcriptional outliers in urothelial carcinoma
Authors: Faltas Bishoy S. M. , Bareja Rohan , Shelkey Ethan , Mayer Rebecca , Sboner Andrea , Rubin Mark A. , Elemento Olivier
Published: July 2016

Background: Urothelial carcinoma (UC) is a major public health problem affecting new 75,000 patients and resulting in 15,000 deaths annually. Despite a variety of genetic and epigenetic alterations described in UC, few therapeutically exploitable drivers have been identified and validated. We hypothesized that transcriptional outliers from primary tumor biopsies could reveal such therapeutically exploitable weaknesses. Identification of these druggable outliers would be critical for individualized therapy of patients with UC. Methods: In order to identify transcriptional outliers we calculated Z-scores for a set of 72 druggable cancer-related genes from RNA sequencing data from our Institute of Precision Medicine (IPM) cohort of advanced platinum-resistant UC. We performed similar outlier analyses on The Cancer Genome Atlas (TCGA) cohort of UC and the Cancer Cell Line Encyclopedia (CCLE) database of urothelial cell lines. Common outliers between IPM and CCLE datasets or between TCGA and CCLE datasets were nominated for further in-vitro testing. Sensitivity scores of cell lines for 130 drugs were extracted from the publicly available cell line browser database and the variance these sensitivity scores across (640) cell lines was calculated. The drugs targeting the outlier genes (real sensitivity z-score) were compared to the mean z-scores of randomly chosen drugs associated with those genes (control sensitive z-score). To investigate the mechanisms underlying comparison of outliers methylation patterns of the promoter regions of outlier genes were examined. Results: 6 druggable outlier genes were common between IPM and CCLE cohorts, and 15 outlier genes between CCLE and TCGA cohorts. Common outliers included FGFR3, KIT, BCL2, ABL1, and SMO. The presence of outlier genes in cell lines correlated with higher sensitivity to drugs predicted to target these genes in comparison to randomly selected drugs (p<0.05). In vitro cell viability assays confirmed sensitivity of RT112 and RT4 cell lines to Dovitinib, an FGFR3 inhibitor as predicted by our algorithm. Outlier genes were frequently involved in gene fusions, amplification or DNA hypomethylation (p<0.02). Conclusions: Identification of druggable transcriptional outliers can elucidate novel oncogenic dependencies and aid in selecting precision therapies for UC patients.

Citation Format: Bishoy S. M. Faltas, Rohan Bareja, Ethan Shelkey, Rebecca Mayer, Andrea Sboner, Mark A. Rubin, Olivier Elemento. Identification of druggable transcriptional outliers in urothelial carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4506.
Abstract 451: Large-scale evaluation of SLC18A2 in prostate cancer reveals diagnostic and prognostic biomarker potential at three molecular levels
Authors: Haldrup Christa , Lynnerup Anne-Sofie , Storebjerg Tine M. , Vang Søren , Wild Peter , Visakorpi Tapio , Arsov Christian , Schulz Wolfgang A. , Lindberg Johan , Grönberg Henrik , Egevad Lars , Borre Michael , Ørntoft Torben F. , Høyer Søren , Sørensen Karina D.
Published: July 2016

Limitations of current diagnostic and prognostic tools for prostate cancer (PC) contribute to over-diagnosis and over-treatment. Here, we investigate the biomarker potential of the SLC18A2 (VMAT2) gene for PC at three molecular levels. Thus, SLC18A2 promoter methylation was analyzed in 767 malignant and 78 benign radical prostatectomy (RP) samples using methylation-specific qPCR and Illumina 450K methylation microarray data. SLC18A2 transcript levels were assessed in 412 malignant and 45 benign RP samples using RNAseq data. SLC18A2 protein was evaluated by immunohistochemistry in 502 malignant and 305 benign RP samples. Cancer-specificity of molecular changes was tested using Mann-Whitney U tests and/or receiver operating characteristic (ROC) analyses. Log rank, uni- and multivariate Cox regression tests were used for survival analyses. We found that SLC18A2 promoter hypermethylation was highly cancer-specific (area under the curve (AUC): 0.923-0.976) and associated with biochemical recurrence (BCR) after RP in univariate analyses. SLC18A2 transcript levels were reduced in PC and had independent prognostic value for BCR after RP (multivariate HR 0.13, P<0.05). Likewise, SLC18A2 protein was down-regulated in PC (AUC 0.898) and had independent prognostic value for BCR (multivariate HR 0.51, P<0.05). Reduced SLC18A2 protein expression was also associated with poor overall survival in univariate analysis (HR 0.29, P<0.05).

Our results highlight SLC18A2 methylation as a new promising biomarker candidate for PC diagnosis. Furthermore, both SLC18A2 RNA and protein expression showed promising prognostic potential beyond routine clinicopathological variables. Thus, novel SLC18A2-based molecular tests could have useful future applications for PC detection and identification of high-risk patients.

Citation Format: Christa Haldrup, Anne-Sofie Lynnerup, Tine M. Storebjerg, Søren Vang, Peter Wild, Tapio Visakorpi, Christian Arsov, Wolfgang A. Schulz, Johan Lindberg, Henrik Grönberg, Lars Egevad, Michael Borre, Torben F. Ørntoft, Søren Høyer, Karina D. Sørensen. Large-scale evaluation of SLC18A2 in prostate cancer reveals diagnostic and prognostic biomarker potential at three molecular levels. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 451.
Abstract 4510: KIT melanomas are developmentally racially biased
Authors: Sanchez Margaret I. , Grichnik James M.
Published: July 2016

KIT is a critical pathway for melanocytic homeostasis and it is often down-regulated in cutaneous melanoma. However, KIT activation plays a critical role in a subpopulation of melanomas especially those in acral locations and melanomas on chronically sun damaged skin. We analyzed exome and RNAseq data from The Cancer Genome Atlas (TCGA) Network (321 cutaneous melanomas in the data set) to identify patterns unique to KIT activation. The melanomas were divided based on known mutually exclusive mutations (BRAF, NRAS and KIT) vs those without (WT). We compared RNA data between each group. KIT group had significantly higher expression of KIT than BRAF, NRAS and WT (p<0.01, FDR<0.01) and isoform 2 expression was higher than 1. KIT melanomas were found to overexpress Wnt pathway, pigmentation and genes involved epithelial-mesenchymal transition. From the exome data, germline SNPs with incidence in ethnic groups (Caucasian, Asian and African) and more likely to be present in a specific melanoma groups were selected. Comparing the 3 ethnicity groups across the 4 tumor groups Asian SNPs were significantly enhanced in KIT tumors, African in WT and Caucasian in BRAF and NRAS melanomas. We evaluated the tumors for the primary type of genetic damage. The three signatures that appeared most divergent were CC>TT for UV, (G/A)C(G)>(G/A)T(G) for deamination, and G>T for oxidative damage. UV and deamination appeared inversely proportional, while oxidative damage appeared to be independent of those other two features. KIT and WT had a greater% of non UV high deamination tumoral environments. A fraction of these tumors also had very high oxidative signatures. We then compared 2 KIT subgroups UV vs non UV (absence of CC>TT mutations) for germline ethnicity differences. Asian SNPs were highly increased in non UV subgroup whereas Caucasian SNPs were in UV subgroup. Further, we divided KIT non UV subgroup into deamination and oxidative damage subgroups and compared ethnicity differences. Deamination was significantly higher in Asians whereas oxidative damage was higher in Caucasians. A similar analysis was done to the WT group, where African SNPs were significantly increased in the non UV subgroup and were primarily associated with oxidative damage. This data implies that KIT mutant melanomas develop in a unique genetic and mutational environments and makes this an ideal system to in which study racial disparities at the molecular level.

Citation Format: Margaret I. Sanchez, James M. Grichnik. KIT melanomas are developmentally racially biased. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4510.
Abstract 4514: Transcription down-regulation of c-Myc through nucleic acid clamp-mediated stabilization of the promoter G-quadruplex
Authors: Hao Taisen , Brooks Tracy
Published: July 2016

MYC overexpression occurs in up to 80% of all cancers. Down-regulating MYC's expression is an effective therapeutic strategy for the treatment of many of these cancers, and particularly for non-Hodgkin's lymphoma (NHL). NHL is the fifth most common cancer type, accounting for 5% of all cancers and 4% of all cancer deaths. Developing MYC-targeting therapeutics will be very impactful to NHL patients. In the current study, we have developed a nucleic acid clamp to transcriptionally down-regulate MYC expression by stabilizing the G-quadruplex (G4) formed in the nuclease hypersensitivity element III1 promoter region. The clamps complement nucleotides on the 5’- and 3’- regions flanking the G4-forming sequence, linked together with an 18 angstrom abasic moiety. To date, the binding affinity and specificity, G4 structure stabilizing ability, MYC down-regulation capability, and the selective cytotoxicity on cancerous vs non-cancerous cell lines of these clamps have been confirmed by EMSA and electronic circular dichroism, DMS footprinting, luciferase reporter assay, and MTS viability assay respectively. Recently, various replacements have been explored to replace the abasic moiety with non-complementary nucleic acids and to optimize the phosphate backbone with peptide nucleic acids. In addition, complexation with block co-polymers is under investigation to develop a functionalizable nanotherapeutic for NHL. The highly selective G4 stabilizing ability of the clamps used in the current approach offers an advantage over traditional G4 stabilizing small molecules. This novel approach is a promising therapeutic for the treatment of MYC related malignancies, and provides a framework for future G4-therapeutic development for other high-value genes, such as kRAS, VEGF, c-KIT and many more.

Citation Format: Taisen Hao, Tracy Brooks. Transcription down-regulation of c-Myc through nucleic acid clamp-mediated stabilization of the promoter G-quadruplex. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4514.
Abstract 4516: Evaluating the chromatin state as a predictive biomarker for BET inhibitor sensitivity in hematological malignancies
Authors: Castillo Joseph , Raisner Ryan , Gascoigne Karen , Dos Santos Gary , Clarke Emer , Huang Alex , Lackner Mark , Mounir Zineb
Published: July 2016

The BET (bromodomain extra-terminal) family of proteins are a group of epigenetic regulators that control gene transcription by reading acetylated lysines on histone tails and recruiting transcription complexes. The various BET inhibitors developed show strong anti-tumor effects against a broad range of hematologic malignancies. The BET inhibitor JQ1 shows strong anti-proliferative activity in sub-sets of multiple myeloma (MM), acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL) and lymphoma cell line models. At present, however, predictive biomarkers of BET inhibitor sensitivity have not been identified. We hypothesize that the chromatin state characterized by various histone post-translational modifications (acetylation, methylation, etc.), can drive sensitivity to BET inhibition. By examining basal expression of epigenetic marks in panels of sensitive and resistant heme cell line models and further validating these histone modification trends in primary AML and multiple myeloma cultures, we may be able to identify predictive biomarkers of BET inhibitor sensitivity in hematological malignancies.

Citation Format: Joseph Castillo, Ryan Raisner, Karen Gascoigne, Gary Dos Santos, Emer Clarke, Alex Huang, Mark Lackner, Zineb Mounir. Evaluating the chromatin state as a predictive biomarker for BET inhibitor sensitivity in hematological malignancies. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4516.
Abstract 4521: Substrate profiling for SETD8 reveals novel protein targets involved in DNA replication and DNA damage response
Authors: Pittella Silva Fabio , Blum Gil , Senevirathne Chamara , Luo Minkui
Published: July 2016

Protein lysine methyltransferases utilize S-adenosyl-L-methionine (SAM) to catalyze the addition of methyl groups to specific lysine residues in both histones and non-histone proteins. Recent evidence indicates that their dysregulation is closely linked to the development and progression of cancer, making them potential therapeutic targets. SETD8 is the sole methyltransferase responsible for mono-methylation of histone H4 lysine 20 (H4K20me1). Its activity is essential for cell viability and has been associated with many essential cellular processes including transcriptional regulation, heterochromatin formation, genomic stability and cell-cycle progression. SETD8 is overexpressed in several types of cancer and may play important roles on malignancy through its trans-methylation activity or by direct interaction with its binding partners. It has been reported that the association between SETD8 and TWIST, a regulator of epithelial-mesenchymal transition, enhances the invasiveness of breast cancer cells. In addition, it was shown that SETD8-mediated methylation of p53 suppresses p53 dependent transcription activation in cancer cells. Despite the identification of a few non-histone proteins such as p53, PCNA and Numb as SETD8's substrates, a comprehensive investigation of new potential substrates is lacking to date. Here we used Bioorthogonal Profiling of Protein Methylation (BPPM) with engineered SETD8 and synthetic SAM analogues to profile novel substrates for SETD8. We identified SETD8 mutants amenable to accommodate non-native SAM analogues containing a terminal alkyne moiety for click chemistry. The engineered SETD8 can transfer this distinct chemical moiety into target proteins for subsequent pulldown and identification of the modified substrates. The BBPM technology applied here revealed previously known substrates of SETD8 as well as novel SETD8 targets. Among the main targets of our interest are those involved in DNA replication and DNA damage response. Our finding is expected to bring new perspectives on the biological importance of SETD8 as well as on its role in carcinogenesis.

Citation Format: Fabio Pittella Silva, Gil Blum, Chamara Senevirathne, Minkui Luo. Substrate profiling for SETD8 reveals novel protein targets involved in DNA replication and DNA damage response. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4521.
Abstract 4522: Epstein-Barr virus infection suppresses the DNA repair mechanisms in nasopharyngeal epithelial cells via reduction of the H3K4me3 mark
Authors: Lung Maria L. , Cheung Arthur KL , Dai Wei , Leong Merrin ML , Tsao. George SW
Published: July 2016

Introduction: Epstein-Barr Virus (EBV) is an oncovirus, which contributes to development of various cancers, including nasopharyngeal carcinoma (NPC). EBV latent proteins play critical roles in modulation host cell histone modifications in order to regulate its signaling pathways. However, the role of EBV in regulation histone modifications in epithelia cell system is still not very clear. Further studies are necessary to characterize the functional role of EBV in regulating epithelial cell modifications.

Aim: in this current study, we aim to investigate the role of EBV infection in regulating a promoter and transcription activation histone marker, H3K4me3, in the host cell genome.

Methodologies: Chromatin immunoprecipitation sequencing (ChIPseq) was performed by using the next-generation sequencing approach. The ChIP reactions were prepared by utilizing the antibody targeting the H3K4me3 mark in two pairs of immortalized non-tumorigenic nasopharyngeal epithelial (NPE) cell lines, which were artificially infected with (550, 550-EBV, 361, and 361-EBV). The ChIPseq results were validated by the ChIP-QPCR and RT-QPCR.

Results: A total of 1747 genes show losses of H3K4me3 in both sets of EBV-infected NPE cell lines. Among them, 628 (36%) genes show losses of H3K4me3 in promoter regions. Interestingly, a total of 18 DNA damage repair signaling members in the base excision repair (BER), homologous recombination, non-homologous end-joining, and the mismatch repair pathways showed significant losses of H3K4me3 in EBV-infected NPE cells. Based on utilizing the DAVID annotation tool for pathway analysis, members in the BER pathway were significantly enriched (FDR = 0.0709, cut-off<0.1). The ChIPseq results were validated by ChIP- and RT-QPCR and showed significant losses of the H3K4me3 and expression of the BER members in both sets of EBV-infected NPE cell lines. The clinical significances were further confirmed by detection of significant down-regulation of the BER members in NPC paired biopsies.

Conclusion: EBV infection induces changes of host cell H3K4me3 levels and results in down-regulation of the BER members.

Acknowledgement: This work was supported by the Research Grants Council of the Hong Kong Special Administrative Region, People's Republic of China: Grant number AoE/M-06/08 to MLL and the Seed Funding Programme for Basic Research of the University of Hong Kong: Grant number 201308159003 to AKLC.

Citation Format: Maria L. Lung, Arthur KL Cheung, Wei Dai, Merrin ML Leong, George SW Tsao. Epstein-Barr virus infection suppresses the DNA repair mechanisms in nasopharyngeal epithelial cells via reduction of the H3K4me3 mark. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4522.
Abstract 4523: Decreased H2B monoubiquitination is associated with enhanced proliferation and resistance to apoptosis in human lung cancer
Authors: Zhang Keqiang , Wang Jinhui , Wu Xiwei , Reno Theresa A. , Tong Tommy R. , Kim Jae , Raz Dan
Published: July 2016

Monoubiquitination of histone H2B (H2Bub1) is an important chromatin modification that plays multiple roles in transcription, mRNA processing, DNA repair, cell differentiation, and maintenance of stemness. Recent studies have indicated that dysregulation of H2Bub1 and the resulting alterations of global gene expression are key contributors in cellular transformation and metastasis. However, the importance of H2B ubiquitination in lung cancer is unknown. Here, by using immunohistochemical analysis (IHC), we have demonstrated that the protein level of H2Bub1 is frequently decreased in a cohort of human lung cancer tissues in comparison to paired adjacent normal tissues. We also found that decrease in H2Bub1 is associated with increased cellular proliferation, as measured by Ki67, and is associated with decreased overall survival. Furthermore, using RNA-seq and transcriptional profiling analysis, we identified that reduction of H2Bub1 via attenuating the expression of histone H2B E3 ubiquitin ligase ring finger protein 20 (RNF20) leads to significant changes of global gene expression, modulating multiple malignancy-promoting genes, including c-Met, E2F2, and BMF. Signaling pathways including p53, DNA replication, DNA repair, and cellular proliferation, and regulation of apoptosis in lung cancer cells are also altered. Additionally, we have further shown that decrease of H2Bub1 by RNF20 knockdown significantly promotes growth, migration/invasion, and strongly enhances resistance to cytotoxic chemotherapy-induced apoptosis in lung cancer cells. Our findings suggest that dysregulation of H2Bub1 signaling may play an important role in growth and drug resistance of lung cancers, and may potentially serve as a prognostic biomarker and therapeutic target for lung cancer patients.

Citation Format: Keqiang Zhang, Jinhui Wang, Xiwei Wu, Theresa A. Reno, Tommy R. Tong, Jae Kim, Dan Raz. Decreased H2B monoubiquitination is associated with enhanced proliferation and resistance to apoptosis in human lung cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4523.
Abstract 4537: Hexavalent chromium induces H4K16 hypoacetylation by NUPR1-mediated inactivation of histone acetyltransferase hMOF
Authors: Chen Qiao Yi , Zhang Xiaoru , Kluz Thomas , Costa Max , Sun Hong
Published: July 2016

Hexavalent chromium [Cr(VI)] is a well-established carcinogen linked to respiratory cancer and has been found at half of US toxic waste sites. In spite of considerable research efforts, the mechanism of Cr(VI)-induced carcinogenesis remains largely unknown. A growing body of evidence suggests that Cr is capable of inducing epigenetic changes, such as DNA methylation, histone modification, and microRNA. Acetylation of histone lysine residues neutralizes the positive charge from their side chains and decreases the affinity between histone tails and DNA, which subsequently leads to increased DNA accessibility and transcriptional activation in the gene promoter region. However, the effect of Cr(VI) on histone acetylation is still not clear. Here, we report that BEAS-2B cells exposed to 5 or 10 uM of Cr(VI) for 24 hours resulted in a striking and dose dependent decrease in H4K16ac. Co-treatment with Cr(VI) and Benzo(a)pyrene diolepoxide (BPDE) induced further decrease in H4K16ac. Cr (VI) transformed cells showed considerable decrease in H4K16ac compared to the control cells, which further indicates the correlation between Cr(VI) exposure and hypoacetylation of H4K16. H4K16 acetylation is known as an important determinant in higher-order chromatin structure and active gene expression. Male Absent on the First gene (MOF) is a H4K16 specific acetyltransferase. Our results indicate that Cr(VI) exposure significantly reduced MOF activity while its expression levels remained the same, thus suggesting that Cr(VI) may affect MOF activity rather than its expression. Moreover, Nuclear protein 1 (NUPR1), a MOF inhibitor, was increased in Cr(VI)-exposed cells. Depletion of NUPR1 in cells by small RNA interference rescued Cr(VI)- reduced H4K16ac. Together, our results indicate that Cr(VI) inhibits MOF activity through inducing NUPR1 expression which subsequently leads to H4K16 hypoacetylation. Since hypoacetylation of H4K16 is a known hallmark of human cancer, the results from our study presents strong evidence supporting the role of H4K16 hypoacetylation in chromium carcinogenesis.

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Citation Format: Qiao Yi Chen, Xiaoru Zhang, Thomas Kluz, Max Costa, Hong Sun. Hexavalent chromium induces H4K16 hypoacetylation by NUPR1-mediated inactivation of histone acetyltransferase hMOF. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4537.
Abstract 4544: FBW7 induces S-phase arrest caused by DNA double strand breaks through targeting SOX9 for proteasomal degradation
Authors: Hong Xuehui , Liu Wenyu , Song Ruipeng , Inuzuka Hiroyuki , Sabaawy Hatem E. , Morgan Katherine M. , Shah Jamie J. , Bunting Samuel F. , Feng Xing , Tsang Chi-Kwan , Shen Zhiyuan , Zheng X. F. Steven , Liu LianXin , Pine Sharon R.
Published: July 2016

SOX9 encodes a transcription factor that governs cell fate specification throughout development and tissue homeostasis. Elevated SOX9 is implicated in the genesis or progression of many human tumors through increasing cell proliferation and epithelial-mesenchymal transition. We observed that, in response to UV irradiation or certain chemotherapeutic agents, SOX9 is actively and rapidly degraded by a ubiquitin pathway dependent mechanism across several different tumor types including lung cancer, colon cancer, osteosarcoma and melanoma, as well as normal human bronchial epithelial cells. We found that SOX9 is phosphorylated by GSK3β at Ser-236, facilitating the direct binding and degradation of SOX9 via the F box protein, FBW7α. We also determined that the de-ubiquitinase, USP28, stabilizes SOX9 under normal conditions by sequestering FBW7, but is released from FBW7 after UV irradiation, allowing FBW7 to bind SOX9 and target it for destruction. DNA damage-induced SOX9 degradation was independent of p53, ATM, ATR and MAPK pathways. Failure to deplete SOX9 attenuated the DNA damage-induced intra-S-phase checkpoint and increased long-term cell survival. Moreover, mutations within the FBW7 phosphodegron binding site of SOX9 prevented SOX9 degradation after DNA damage, and incurred resistance of non-small cell lung cancer (NSCLC) cells to cisplatin in vivo. We found that cancer patients with tumors expressing high Sox9 and low Fbw7 levels exhibit inferior survival. Our discovery reveals a novel function of SOX9 in the cellular response to DNA damage. Induced degradation of SOX9 may be part of the protection mechanisms to maintain genomic stability. This new regulatory mechanism of the FBW7-SOX9 axis in cancer could have diagnostic and therapeutic implications.

Citation Format: Xuehui Hong, Wenyu Liu, Ruipeng Song, Hiroyuki Inuzuka, Hatem E. Sabaawy, Katherine M. Morgan, Jamie J. Shah, Samuel F. Bunting, Xing Feng, Chi-Kwan Tsang, Zhiyuan Shen, X. F. Steven Zheng, LianXin Liu, Sharon R. Pine. FBW7 induces S-phase arrest caused by DNA double strand breaks through targeting SOX9 for proteasomal degradation. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4544.
Abstract 4548: High throughput siRNA screens uncover a high rate of USP8 and ESCRT pathway dependency in squamous carcinoma cell lines
Authors: Zhong Wendy , Cosgrove Elissa , Swearingen Elissa , Ollmann Mike , Banerjee Jayee , Watson Vivienne , Jaeckel Peter , Pfreimer Mariana , Materna-Reichelt Silvia , Beckmann Holger , Kassner Paul , Ruefli-Brasse Astrid , Nolan-Stevaux Olivier
Published: July 2016

USP8 and the ESCRT pathway (endosomal sorting complex required for transport) are required for cellular homeostasis through key functions in shuttling ubiquitinated proteins towards lysosomal degradation, and through regulating the maturation of autophagosomal structures. In large-scale siRNA screens, the vast majority of cancer cell lines do not demonstrate dependency on USP8 or ESCRT pathway components for viability. However, we identified three cell lines (HCC70, HCC1954 and PFSK1) that are acutely dependent on USP8 and other ESCRT components (HGS, TSG101) for viability. Using a transcriptome-wide association approach, we found that these three USP8-dependent cell lines also had in common the expression of SerpinB3, also known as SCCA1 (Squamous Cell Carcinoma Antigen 1). After selecting additional Squamous Cell Carcinoma cell lines for further validation of USP8-dependency by siRNA screening, we found that Squamous Carcinoma cell lines, irrespective of their SerpinB3 expression status, were far more likely to be dependent on USP8 for viability (23%; N = 22) than cancer cell lines of non-Squamous epithelial origin (4.5%; N = 67). To unravel possible molecular mechanisms underpinning the requirement of USP8 for the viability of USP8-dependent Squamous Carcinoma cell lines (including SCABER, BICR22, CALU1 and EBC1), we conducted additional transcriptome association studies and genetic interaction screens to uncover genes that are synthetic lethal with USP8 knock-down.

Citation Format: Wendy Zhong, Elissa Cosgrove, Elissa Swearingen, Mike Ollmann, Jayee Banerjee, Vivienne Watson, Peter Jaeckel, Mariana Pfreimer, Silvia Materna-Reichelt, Holger Beckmann, Paul Kassner, Astrid Ruefli-Brasse, Olivier Nolan-Stevaux. High throughput siRNA screens uncover a high rate of USP8 and ESCRT pathway dependency in squamous carcinoma cell lines. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4548.
Abstract 4553: Identification of CD30/TNFRSF8 as a primary target of the Myc oncoprotein and potential biomarker of Myc-driven cancer
Authors: Gennaro Victoria , Zhang Xiao-yong , DeSalle Lauren , Yu Duonan , Thomas-Tikhonenko Andrei , Vakoc Christopher , McMahon Steven B.
Published: July 2016

Pathological activation of the transcription factor Myc induces a multitude of human malignancies. In Myc-driven tumor progression, there is a robust dependence on Myc activity; however, strategies developed to explicitly modulate Myc function in cancer have yielded little clinical success. Patients harboring Myc-dependent tumors would benefit from a therapy that circumvents molecular targeting of Myc expression and instead directs against a distinct downstream effector.

Our preliminary data from an unbiased expression-profiling screen identify CD30 as a primary target of the Myc oncoprotein. CD30 is a member of the tumor necrosis factor superfamily and resides on the extracellular membrane; it is highly expressed in several lymphomas while acutely restricted in normal cells. Within the last few decades, CD30 has emerged as a diagnostic marker and therapeutic target of many lymphoproliferative diseases. However, the underlying mechanisms that regulate CD30 expression remain unclear. We report that CD30 is regulated at the transcriptional level by Myc. Through a genetic and biochemical approach, we define CD30 induction in a MYC-dependent manner across a variety of human cell lines of both lymphomagenic and non-lymphomagenic origin. Furthermore, deliberate modulation of Myc-activity demonstrates a positive correlation with CD30 surface protein expression in multiple malignancy models. With CD30 induction as a potential mechanism by which to identify and target Myc-driven oncogenesis, we can reshape detection and treatment of Myc-regulated cancer.

Citation Format: Victoria Gennaro, Xiao-yong Zhang, Lauren DeSalle, Duonan Yu, Andrei Thomas-Tikhonenko, Christopher Vakoc, Steven B. McMahon. Identification of CD30/TNFRSF8 as a primary target of the Myc oncoprotein and potential biomarker of Myc-driven cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4553.
Abstract 4567: Functional characterization of P58IPK-PERK pathway in prostate cancer cells
Authors: Sheng Xia , Storm Margrethe , Jin Yang , Saatcioglu Fahri
Published: July 2016

Androgen signaling is important for the normal development and function of the prostate as well as for prostate cancer (PCa). We recently found that androgens activated the IRE1α-XBP1 arm of the canonical unfolded protein response (UPR) pathways and simultaneously inhibited PERK-eIF2α signaling. Activation of the IRE1α-XBP1 arm was mediated by direct binding of the androgen receptor (AR) in the vicinity of IRE1, as well as XBP1s target genes, and increase in their expression. Consistently, AR and IRE1α pathway gene expression are correlated in human PCa samples and XBP1s protein expression is significantly increased in cancer compared to normal prostate. However, the mechanisms behind androgen mediated inhibition of PERK-eIF2α signaling are not clear at present. One possible mediator in this regard is P58IPK, an XBP1s target gene that can interact with and inhibit PERK and eIF2α phosphorylation. Here, we show that P58IPK expression is increased by androgens in a time-dependent manner and that it plays a pro-survival role in PCa cells. P58IPK knockdown activated PERK expression as well as subsequent eIF2α phosphorylation when induced with the UPR activator thapsigargin. These findings suggest that P58IPK mediates, at least in part, the differential androgen effects between the IRE1α and PERK signaling in PCa and may be a potential therapeutic target.

Citation Format: Xia Sheng, Margrethe Storm, Yang Jin, Fahri Saatcioglu. Functional characterization of P58IPK-PERK pathway in prostate cancer cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4567.
Abstract 4570: Decreased interleukin-17RA expression inhibits the tumorigenesis and independently predicts good prognosis of colorectal cancer patients
Authors: YANG CHIH-YUNG , Jiang Jeng-Kai
Published: July 2016

Background:

Interleukin-17 receptor type A (IL-17RA) plays critical role in promoting early colorectal tumor development and affects immune response in tumorigenesis. Our previous study have reported interleukin-17A modulated tumorigenesis and affected metastasis in colorectal cancers, but the roles of its receptor (IL-17R) in colorectal cancers remain unknown. This study explores potential role and function of IL-17RA in colorectal cancers.

Materials and Methods

The expression of IL-17RA was determined in colorectal cancer tissues and adjacent normal tissues using quantitative real-time PCR and immunohistochemistry. The IL-17RA expression level and clinical parameters were then analyzed. To investigate the functional significance of IL-17RA, IL-17RA knockdown cells were analyzed using transwell assay in vitro and implanted subcutaneously in mice, and monitored for primary tumor growth and angiogenesis.

Results

IL-17RA was overexpression in colorectal cancer tissues compared with adjacent normal tissues (P<0.05).The elevated expression level of IL-17RA was associated with poor survival (P<0.001). In vitro, the IL17RA knockdown cells reduced migration and invasion. In mice, the decreased IL-17RA inhibited tumor growth and angiogenesis.

Conclusions

These results demonstrated that IL-17RA plays a critical role in growth, angiogenesis and prognosis of colorectal cancer.

Citation Format: CHIH-YUNG YANG, Jeng-Kai Jiang. Decreased interleukin-17RA expression inhibits the tumorigenesis and independently predicts good prognosis of colorectal cancer patients. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4570.
Abstract 4576: Hepatocyte nuclear factor 4 alpha suppresses cell proliferation and induces cellular senescence and apoptosis in prostate cancer cells
Authors: WANG Zhu , Chan Franky Leung
Published: July 2016

Hepatocyte nuclear factor 4α (HNF4α, NR2A1) is a highly conserved member of the nuclear receptor superfamily of ligand-dependent transcription factors. Recent advances show that it is a key transcriptional regulator of many genes, involved in xenobiotic and drug metabolism and also cancers of gastrointestinal tract. However, the exact functional roles of HNF4α gene in prostate cancer progression are still not fully understood. In this study we used the overexpression (gain-of-function) and knockdown (loss-of-function) approaches to determine the functional roles of HNF4α in prostate cancer. Our results showed that HNF4α exhibited a reduced expression pattern in many prostate cancer cells compared to immortalized prostatic cell lines. Its overexpression could significantly inhibit the cell proliferation of prostate cancer cells, and trigger the cellular senescence and apoptosis by activation of p21 signal pathway in a p53-independent manner. We showed that stable overexpression of HNF4α could significantly induce G2/M arrest in PC3 cells, while shRNA-mediated knockdown of HNF4α could induce G1 growth arrest, suggesting that HNF4α might play a negative role in the cell cycle regulation of PC3 cells. Moreover, stable HNF4α knockdown could confer resistance to paclitaxel treatment and enhance colony formation capacity in prostate cancer cells. Together, our results suggest that HNF4α may play a tumor suppressor function in prostate cancer progression.This work was supported by a Direct Grant for Research 2015-2016 (2015. 1. 064), CUHK.

Citation Format: Zhu WANG, Franky Leung Chan. Hepatocyte nuclear factor 4 alpha suppresses cell proliferation and induces cellular senescence and apoptosis in prostate cancer cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4576.