Hepatitis B virus X protein contributes to hepatocellular carcinoma via upregulation of KIAA1429 methyltransferase and mRNA m6A hypermethylation of HSPG2/Perlecan [RNA-Seq]

Chronic hepatitis B virus (HBV) remains to be the most common risk factor of hepatocellular carcinoma (HCC). While work has primarily focussed on understanding the direct and indirect mechanisms of Hepatitis B virus X protein (HBx) mediated hepatocarcinogenesis, from genetic and epigenetic perspectives, its influence on RNA modification mediated onset of liver malignancies is less well understood. This study explored the role of HBV-encoded HBx in altering the m6A methylome profile and its implications on the pathogenesis of HCC. We established HBx expressing stable HCC cell lines, Huh7-HBx and HepG2-HBx, and explored the transcriptomic and epitranscriptomic profiles by RNA-seq and MeRIP-seq, respectively. Preliminary results suggest that HBx promotes liver cell proliferation, migration, survival and overall m6A methylation in HCC cells and is involved in modulating the extracellular matrix. We show that HBx mediates liver cell transformation by upregulating KIAA1429 methyltransferase. HBx also drives the expression and hypermethylation of the extracellular matrix protein HSPG2/Perlecan and promotes tumourigenesis. Our findings indicate a potential interaction between KIAA1429 and HSPG2, thus could be novel targets in combating HBx-driven HCC and warrants further investigation. To decipher the underlying mechanisms by which HBx exerted tumour promoting effects in HCC, we carried out RNA sequencing to display the transcriptional changes in Huh7 and HepG2 that stably express HBx. We used two biological replicates per sample and compared between untreated (without Dox treatment) and treated (with Dox treatment).