HBx Promotes Liver Cancer Cells to Escape NK-92 Cell Attack by Mediating ADAM10 to Enzyme Cut MICA/B Shedding From Cancer Cell Membrane.

MICA/B shedding from the membrane of cancer cells can inhibit natural killer (NK) cells from attacking hepatocellular carcinoma (HCC). This study explored the role of HBx in mediating MICA/B shedding. The expression of HBx, MICA/B and HIF-1α in HBV-infected HCC was analysed using bioinformatics, and the localization of these proteins in tissues was verified using immunohistochemistry and immunofluorescence. HBx-related signalling pathways were screened using RNA sequencing and KEGG pathway enrichment analyses. The expression of ADAM10 and MICA/B was detected by Western blotting, and the dynamic changes of MICA/B in the membrane and supernatant were evaluated by flow cytometry and ELISA. The HIF-1α inhibitor (LW-6) and ADAM10 inhibitor (GI254023X) were used to treat the HCC cells. The killing effect of NK-92 cells on HCC cells was evaluated using lactate dehydrogenase release, cytotoxicity assays, clone formation and live-cell imaging, and the secretion levels of IFN-γ, IL-2 and IL-10 were measured. These results indicated that HBx, MICA/B and HIF-1α were highly expressed in HBV-infected HCC tissues. HBx promotes shedding of MICA/B from HCC cell membranes by upregulating the activity of ADAM10. LW-6 reversed the induction effect of HBx on ADAM10 and GI254023X significantly restored MICA/B levels on the membrane surface of HCC cells. Overexpression of HBx increases the resistance of HCC cells to NK-92 cells and inhibits the secretion of IFN-γ, IL-2 and IL-10. In conclusion, HBx regulates the expression of ADAM10 by activating the HIF-1α signalling pathway. ADAM10 cuts MICA/B shedding from the membrane surface of HCC cells, resulting in escape attack by NK-92 cells.