Abstract 3813: Role of CDKN2B antisense RNA 1 in Epstein-Barr virus associated gastric carcinoma

Abstract

Abstract Background: Epstein-Barr Virus (EBV)-associated gastric carcinoma (GC) (EBVaGC) is a subtype of GC which represents approximately 10% of this tumor. CDKN2B antisense RNA 1 (CDKN2B-AS1) is a long non-coding RNA associated with chronic diseases like cardiovascular disease and cancer. This study aimed to evaluate if the loss of CDKN2B-AS1 shifted the balance of the competing endogenous RNA (ceRNA) networks favoring an apoptosis resistant phenotype through ebv-miR-BART4-5p/BID in EBVaGC. Material and Methods: Seven gastric cancer cell lines were used to determine the expression of CDKN2B-AS1. Specific cell lines were used for CDKN2B-AS1 inhibition assays, the transfection of ebv-miR-BART4-5p and the binding between CDKN2B-AS1 and ebv-miR-BART4-5p. The detection of BID protein was determined by Western Blot. To validate the in vitro results, we detected CDKN2B-AS1, BID, and ebv-miR-BART4-5p expression levels by RT-qPCR in four EBVaGC positive and five negative cases. Apoptosis was detected by in situ hybridization (ISH). Results and Discussion: CDKN2B-AS1 is expressed at higher levels in NCI-N87 and SNU-1 cell lines and at lower levels in AGS and KATO-III. A significant decrease in BID protein expression was observed after co-transfection with ebv-miR-BART4-5p and CDKN2B-AS1 inhibitor. However, these results were not significant at mRNA level. The luciferase assay validated the predicted binding between ebv-miR-BART4-5p and CDKN2B-AS1. In EBVaGC samples, a significant decrease in BID expression and cleaved caspase-3 in the presence of miR-BART4-5p was observed. Our results show that decreasing CDKN2B-AS1 expression favors viral miR binding on BID mRNAs through ceRNA networks. Also, these results could explain why positive EBVaGCs have lower apoptosis rate than EBVaGC negative cases. Grant support: ANID/FONDECYT/POSTDOCTORADO/3201028, CONICYT-FONDAP-15130011, FONDECYT-1191928 Citation Format: Keila Torres, Wilda Olivares, Gonzalo Carrasco, Andres Rodriguez, Alejandro H. Corvalan. Role of CDKN2B antisense RNA 1 in Epstein-Barr virus associated gastric carcinoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3813.