Down-regulation of microRNA-21 inhibits cell proliferation and invasion of high-invasion liver cancer stem cells.

OBJECTIVE: Cancer stem cells (CSCs) play critical roles in tumorigenesis, tumor recurrence and metastasis. This study aims to investigate the effects of small interfere microRNA-21 RNA (miR-21 RNAi) on cell proliferation, invasive ability of high-invasion liver cancer stem cells (H-ILCSCs), HCCLM3 and HL-7702 cells.

MATERIALS AND METHODS: pLVX-shRNA2 lentiviral vector system was established, packaged and transfected into H-ILCSCs, HCCLM3 and HL-7702 cells. Cell counting kit-8 (CCK-8) assay was performed to observe cell viabilities of cells. Transwell assay was conducted to evaluate the invasion potential of H-ILCSCs, HCCLM3 and HL-7702 cells. Quantitative PCR (qPCR) assay was used to examine the miR-21 levels in different cell lines.

RESULTS: pLVX-anti-miR21 lentiviral vector system was successfully established. miR-21 levels were down-regulated in anti-miR-21 gene steady expression cell lines compared to untreated cells (p<0.05). miR-21 levels were significantly lower in H-ILCSC2-LV-anti-miR-21 group compared to HCCLM3-anti-miR-21 and HL7702-anti-miR-21 (p<0.05). miR-21 inhibition significantly decreased cell proliferation and invasion compared to untreated cells (p<0.05). Cell proliferation and invasive ability of H-ILCSC2-LV-anti-miR-21 group were significantly higher compared to HCCLM3-anti-miR-21 and HL7702-anti-miR-21 (p<0.05). There were even not effects of miR-21 RNAi treatment on the cell proliferation and invasion of HL-7702 cells.

CONCLUSIONS: The down-regulation of miR-21 significantly inhibited the cell proliferation and invasion abilities of H-ILCSCs and HCCLM3 cells, and illustrated higher effects on H-ILCSCs.