Achaete-scute family bHLH transcription factor 2 activation promotes hepatoblastoma progression

Abstract

Achaete-scute family bHLH transcription factor 2 (ASCL2) is highly expressed in hepatoblastoma (HB) tissues, but its role remains unclear. Thus, biological changes in the HB cell line HepG2 in response to induced ASCL2 expression were assessed. ASCL2 expression was induced in HepG2 cells using the Tet-On 3G system, which includes doxycycline. Cell viability, proliferation activity, mobility, and stemness were evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, colony-formation, migration, invasion, and sphere-formation assays. Quantitative reverse-transcription polymerase chain reaction was used to assess the expression of markers for proliferation (CCND1 and MYC), epithelial-mesenchymal transition (EMT; SNAI1, TWIST1, and ZEB1), mesenchymal-epithelial transition (CDH1), and stemness (KLF4, POU5F1, and SOX9). Compared with the non-induced HepG2 cells, cells with induced ASCL2 expression showed significant increases in viability, colony number, migration area (%), and sphere number on days 7, 14, 8, and 7, respectively, and invasion area (%) after 90 h. Furthermore, induction of ASCL2 expression significantly upregulated CCND1, MYC, POU5F1, SOX9, and KLF4 expression on days 2, 2, 3, 3, and 5, respectively, and increased the ratios of SNAI1, TWIST1, and ZEB1 to CDH1 on day 5. ASCL2 promoted the formation of malignant phenotypes in HepG2 cells, which may be correlated with the upregulation of the Wnt signaling pathway-, EMT-, and stemness-related genes. ASCL2 activation may therefore be involved in the progression of HB.

Keywords: Wnt signaling pathway; basic helix-loop-helix transcription factor; growth; hepatoblastoma; phenotype.