miR-205 Reverses MDR-1 Mediated Doxorubicin Resistance via PTEN in Human Liver Cancer HepG2 Cells

The aim of the recent study was to investigate the effects of miR-205 on reversing Doxorubicin (DOX) resistance, as chemotherapeutic agents through up-regulation of PTEN in human liver cancer HepG2 cells.

In this experimental study, the drug resistance in liver cancer cells via drug efflux inhibition and enhancing apoptosis by the regulation of PTEN and multi-drug resistance/ P-glycoprotein (MDR/P-gp) expression was revealed. Using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, effect of DOX on cell proliferation was evaluated after miR-205 transfection in HepG2 and HepG2/DOX cells. Activity of P-gp on drug efflux was measured by the Rhodamine 123 (Rho-123) assay. PTEN mRNA expression levels were measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and flow cytometry was used to measure the apoptotic ratio of HepG2/DOX cells.

miR-205 overexpression considerably inhibited the HepG2/DOX cells viability (P<0.05). qRT-PCR results revealed that PTEN is a pivotal regulator in PI3K/Akt/P-gp axis. Overexpression miR-205 resulted in up-regulation PTEN and ultimately down-regulation of P-gp. This inhibits drug resistance, proliferation and induces apoptosis in HepG2/DOX cells (P<0.05). Whilst, treatment with 10 μM of special inhibitors, including LY294002 (PI3K) or PD098059 (MAPK), increased Rho 123-associated MFI, treatment with 10 μM of SF1670 (PTEN) almost abolished the effect of miR-205 overexpression (P<0.05). Finally, we found that miR-205 was down-regulated in HepG2/DOX cells, and its overexpression led to enhancing apoptosis with re-sensitization of HepG2/DOX cell lines to DOX through PTEN/PI3K/ Akt/MDR1 pathway.

These findings may introduce miR-205 as a predictive biomarker and a potential treatment target for liver cancer therapy during MDR.