METTL3 and HERC4: Elevated Expression and Impact on Hepatocellular Carcinoma Progression

Methyltransferase-like 3 (METTL3) and HECT and RLD domain containing E3 ubiquitin protein ligase 4 (HERC4) have been studied in the field of oncology; however, their roles and interaction in hepatocellular carcinoma (HCC) await elucidation. Initially, METTL3 and HERC4 expressions in normal and HCC samples were predicted employing the UALCAN database, and the targeting relationship between these two was explored via coimmunoprecipitation assay. Following the quantification on N6-methyladenosine (m⁶A) enrichment, the localization of METTL3 and HERC4 on HCC cells was visualized via immunofluorescence assay. The effects of METTL3 and HERC4 on HCC cells proliferation and migration were determined in vitro assays. METTL3 and HERC4 expressions were quantified via quantitative polymerase chain reaction, and those of metastasis-related proteins N-cadherin and vimentin were calculated with immunoblotting assay. Furthermore, the levels of angiogenic factors such as vascular endothelial growth factor and basic fibroblast growth factor were measured by enzyme-linked immunosorbent assay. METTL3 and HERC4 expressed highly in HCC and their expressions were positively correlated with tumor grade. METTL3 overexpression enhanced the expression of HERC4 and promoted the proliferation and migration abilities of HCC cells. Specifically, METTL3 overexpression increased vimentin and N-cadherin expressions, while its silencing did conversely. Besides, HERC4 overexpression reversed the effects of METTL3 silencing on the proliferation and migration as well as the levels of angiogenic factors in HCC cells. This study reveals the upregulation of METTL3 and HERC4 expression in HCC and their role in HCC by enhancing the proliferation, migration, and angiogenesis potential of HCC cells.