Abstract 207: Decoding the circRNA-miRNA-mRNA regulatory network in hepatitis B Virus-driven hepatocellular carcinoma.

Abstract Integration of the hepatitis B virus (HBV) genome into the host chromosome of infected patients poses a threat to those with HBV-associated hepatocellular carcinoma (HCC) due to challenges in early diagnosis and poor prognosis. CircRNAs are known for their oncogenic and biomarker potential in various cancers, including HBV-HCC, by sequestering tumor suppressive miRNAs, which, when free, can silence the expression of oncogenic mRNAs. Therefore, we aimed to identify the circRNA-miRNA-mRNA axis in HBV-integrated HCC cell lines to find prognostic biomarkers specific to HBV-HCC patients. We identified dysregulated host circRNA and mRNA from HBV-negative and HBV-integrated cells using RNA-seq followed by differential gene expression analysis with DESeq and performed pathway analysis using GSEA. Junctional sequences of the circRNAs were validated by Sanger sequencing of the amplified products. RT-qPCR further confirmed the dysregulation of 9 randomly selected circRNAs chosen from those with the highest fold-change and adjusted p-values. The miRNA partners for each of the circRNA idenfied using mirDB. miRNA expression validation was performed using the publicly available GEO database of same cells and cumulative distribution plots were generated to assess the fold change of mRNAs in potential binding miRNA partners. The mRNA targets for 10 miRNA ECDF plots were subjected to GO and KEGG pathway analysis, and hub genes were identified using STRING cytohubba protein-protein interaction (PPI) analysis. Survival analysis of hub genes was plotted, and a competitive endogenous RNA (ceRNA) network was constructed using Cytoscape.We identified 494 dysregulated circRNAs, 311 dysregulated miRNAs and 10,419 dysregulated mRNA in HBV-integrated cells. circADGRL2 (∼25-fold) showed the highest upregulation and miR-361-5p acted as a central node of multiple circRNAs: circADGRL2, circPROX1 and circPALS2. BDNF, a target mRNA of miR-361-5p, was identified as the highest risk ratio in HBV-HCC patients, suggesting a possible circADGRL2-miR-361-5p-BDNF axis. The target mRNAs of miRNAs were found to be associated with several cancer pathways, such as MAPK and RAS. Our data indicate that HBV integration reprograms the circRNA-miRNA-mRNA axis, leading to a poor prognosis for HBV-HCC patients. Citation Format: Kainat Ahmed, Anwaruddin Mohammad, Nan Chaiyariti, Danya Sankaranarayanan, Pankaj Kumar, Sudhakar Jha. Decoding the circRNA-miRNA-mRNA regulatory network in hepatitis B Virus-driven hepatocellular carcinoma abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 207.