Upregulation of MiR-340-5p Reverses Cisplatin Sensitivity by Inhibiting the Expression of CDK6 in HepG2 Cells

Cisplatin (CDDP) has been successfully used in chemotherapy for liver cancer. However, the development of CDDP resistance in HepG2 cells usually leads to relapse and a worsening prognosis. MiR-340-5p has attracted much attention because of its ability to affect cell resistance. This project is intended to explore the role of miR-340-5p and CDK6 in CDDP-R HepG2 cells and provide new ideas for the treatment of liver cancer. A dual-luciferase reporter assay was used to confirm the targeting relationship between miR-340-5p and CDK6. We constructed a CDDP-resistant model of HepG2 cells to examine the effect of miR-340-5p on the drug sensitivity of HepG2 cells. CDDP-R HepG2 cells were transfected with miR-340-5p overexpression plasmid and CDK6 silencing plasmid. QRT-PCR was used to detect the expression of miR-340-5p and CDK6. A western blot was performed to determine the expression of CDK6, CyclinD1, and CyclinD2. CCK-8, flow cytometry, TUNEL and Clonogenic assays were also carried out to detect CDDP-R HepG2 cells. There is a targeting relationship between miR-340-5p and CDK6. The drug resistance of CDDP-R HepG2 cells was significantly higher than that of CDDP-S HepG2 cells. CDDP-R HepG2 cells transfected with both miR-340-5p overexpressing plasmid and CDK6 silencing plasmid showed a lower proliferation ability, cell cycle arrest in the G0/G1 phase, and lower drug resistance compared with single CDDP-R HepG2 cells. Overexpression of miR-340-5p aggravated CDDP-R HepG2 cells' apoptosis and inhibited cell viability. Overexpression of miR-340-5p could reverse the sensitivity of HepG2 cells to CDDP by inhibiting the expression of CDK6 in HepG2 cells.