ARID1B/SUB1-activated lncRNA HOXA-AS2 drives the malignant behaviour of hepatoblastoma through regulation of HOXA3.

It has been becoming increasingly evident that long non-coding RNAs (lncRNAs) play important roles in various human cancers. However, the biological processes and clinical significance of most lncRNAs in hepatoblastoma (HB) remain unclear. In our previous study, genome-wide analysis with a lncRNA microarray found that lncRNA HOXA-AS2 was up-regulated in HB. Stable transfected cell lines with HOXA-AS2 knockdown or overexpression were constructed in HepG2 and Huh6 cells, respectively. Our data revealed knockdown of HOXA-AS2 increased cell apoptosis and inhibited cell proliferation, migration and invasion in HB. Up-regulation of HOXA-AS2 promoted HB malignant biological behaviours. Mechanistic investigations indicated that HOXA-AS2 was modulated by chromatin remodelling factor ARID1B and transcription co-activator SUB1, thereby protecting HOXA3 from degradation. Therefore, HOXA-AS2 positively regulates HOXA3, which might partly demonstrate the involvement of HOXA3 in HOXA-AS2-mediated HB carcinogenesis. In conclusion, HOXA-AS2 is significantly overexpressed in HB and the ARID1B/HOXA-AS2/HOXA3 axis plays a critical role in HB tumorigenesis and development. These results might provide a potential new target for HB diagnosis and therapy.