Fig. 6.
MORC2 promotes stemness, chemoresistance, and tumorigenicity of HCC cells by inhibiting NF2 and KIBRA. a–d Control (Lv-ctrl) and MORC2-expressing (Lv-MORC2) HepG2 cells were infected with empty vectors or lentivirus encoding NF2 or KIBRA. MORC2+/+ and MORC2−/− PLC cells were infected with lentivirus delivering scramble shRNA, or NF2-, or KIBRA- specific shRNA. The percentages of liver cancer stem cells (Lgr5+ cells) were examined by flow cytometry (a). Single cells were seeded in stem cell medium to grow as tumorspheres and representative images were shown (b). The single cells from primary and secondary tumorspheres were cultured in stem cell medium in a limiting dilution manner for 14 days to calculate the frequencies of sphere-initiating cells. Tumorspheres with a diameter larger than 50 μm were counted (c). Cells were treated with Sorafenib (4 μM for HepG2 cells and 8 μM for PLC cells) for 48 h and cultured in normal medium for 10 days to examine colony formation capacity (d). Colonies with a diameter greater than 75 μm were counted. Representative images were shown. e The growth kinetics of subcutaneous tumors generated by indicated PLC cells in nude mice (1 × 106 cells per injection, n = 5 mice). Xenograft tumors were dissected and tumor weight was presented as the mean ± SD. f The frequencies of cancer-initiating cells (CICs) of indicated PLC cells were analyzed by extreme limiting dilution assays (ELDAs) in NOD/SCID mice. Representative images are shown (b, e). Data are presented as the mean ± SD (a, d, e) or mean ± 95% confidence interval of each group from triple replicate (c). *P < 0.05