Abstract B34: LINC00886, a risk locus-associated long noncoding RNA, promotes ovarian cancer progression

Abstract

Abstract Background: Recent genome-wide association studies (GWAS) have identified a plethora of SNPs that cluster at loci associated with increased epithelial ovarian cancer (EOC) risk. The functional validation of genes in such risk loci focused primarily on the protein-coding space while long noncoding RNAs (lncRNAs) were disregarded. Given the emerging evidence that lncRNAs can act as oncogenes and tumor suppressors, we seek to evaluate the functional role of EOC risk locus-associated lncRNAs in EOC development. Methods: We interrogated GWAS for EOC and the FANTOM-CAT database for lncRNAs to identify EOC risk-associated SNPs that lie within lncRNA regulatory regions. We first prioritized the lncRNAs that are associated with EOC risk loci using public databases including GTEx and TCGA. To assess the oncogenic potential of these lncRNAs, we performed in vitro functional assays such as proliferation, colony formation, anchorage-independent growth and migration by overexpressing and silencing candidate lncRNAs in fallopian tube secretory epithelial and ovarian cancer cells. To validate our findings in vivo, we intraperitoneally injected OVCAR-8 cells into immunocompromised mice and evaluated tumor growth. LncRNA subcellular localization was evaluated based on qPCR from cytoplasmic and nuclear RNA. Further, we investigated expression changes upon lncRNAs overexpression in OVCAR-8 and FT282 cells by RNA sequencing (RNA-seq) and predicted shared microRNAs (miRNA) binding sites using LncBase Predicted v.2 and TargetScanHuman 7.2. Results: We identified 5 candidate risk locus-associated lncRNAs (CATG00000115318.1, HAGLR, LINC00886, CATG00000117550.1, and CTD-2521M24.8). Functional assays showed that LINC00886 promoted cancer cell proliferation and colony formation in vitro. Overexpression of LINC00886 in OVCAR-8 cells significantly promoted peritoneal dissemination in a xenograft model. LINC00886 was mainly localized to the cytoplasm, suggesting it could function by decoying miRNAs. Interestingly, we observed that LINC00886 overexpression increased the levels of several oncogenes, of which several (ROR2, TNFSF14, GPNMB, LTB, and ZBTB20) share miRNA binding sites with LINC00886. Conclusion: LINC00886, a risk loci-associated lncRNA, promotes an aggressive phenotype in ovarian cancer, suggesting an oncogenic function. We are currently investigating the molecular mechanism of LINC00886 as a ceRNA in ovarian cancer progression. Citation Format: Koji Nakamura, Brett M. Reid, Thomas A. Sellers, Florian A. Karreth. LINC00886, a risk locus-associated long noncoding RNA, promotes ovarian cancer progression [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr B34.