Interaction of LncRNA-MALAT1 and MiR-124 Regulates HBx-induced Cancer Stem Cell Properties in HepG2 Through PI3K/Akt Signaling

Background: Hepatitis B virus X protein (HBx) plays a crucial role in initiating and promoting HBV-induced hepatocellular carcinoma (HCC) development. Reports indicated that HBx promotes cancer stem cell (CSC) generation, which may be associated with HBV-related HCC. Noncoding RNA miR-124 and long noncoding RNA (lncRNA)-metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) were considered to be involved deeply in the progress of HBx-related HCC. Hence, the underlying mechanism of miR-124 and lncRNA-MALAT1 in regulating HBx-promoted CSC needs to be studied.

Materials And Methods: In present study, HepG2-X cell line was induced by transfect HBx into HepG2 cells. Overexpressing of miR-124 or silencing of lncRNA-MALAT1 was completed by transfecting miR-124 mimic or shMALAT1 into HepG2-X cells. HBx-induced CSC properties and tumorigenic potential of HepG2 cells were determined by detecting CSC marker expression, colony formation assay, and xenograft tumorigenesis. The mechanism of HBx-induced CSC properties was explored by PI3K/Akt inhibitor. Interaction of miR-124 and lncRNA-MALAT1 was detected by luciferase reporter assay.

Results: HBx promoted CSC properties through upregulating stemness markers and reprogramming proteins, and contributed to tumorigenicity of HepG2-X cells both in vivo and in vitro. Inhibition of Akt activation blocked the HBx-stimulated reprogramming proteins and stemness markers. HBx upregulated lncRNA-MALAT1 expression while downregulating miR-124 expression in HepG2-X cells. miR-124 interacts with lncRNA-MALAT1 by direct targeting. Overexpression of miR-124 or silencing of lncRNA-MALAT1 both blocked HBx-induced CSC generation, stemness-related factor activation and tumorigenicity via PI3K/Akt signaling.

Conclusion: Our results demonstrated that miR-124 interact with lncRNA-MALAT1 and involve in regulating HBx-induced CSC properties via PI3K/Akt signaling.