Résumé
OBJECTIVE To investigate the effect and mechanism of miR-152-3p on the resistance to paclitaxel(PTX)of PTX-resistant ovarian cancer cells(A2780T cells).METHODS ① Ovarian cancer parent cells(A2780 cells)and A2780T cells were treated with PTX(1.875,3.75,7.5,17 and 23 μmol·L-1)for 48 h.Cell viability was evaluated by MTT assay,and the 50%inhibitory concentration(IC50)and drug resistance index of A2780T cells were calculated.Western blotting was used to detect the expres-sions of resistance protein P-glycoprotein(P-gp),multidrug resistance related protein 1(MRP1)and adenosine triphosphate binding transporter G superfamily member 2(ABCG2).② Real-time fluorescent quantita-tive PCR(RT-qPCR)was used to detect the expressions of miR-152-3p in A2780 and A2780T cells.The lipid-mediated transient transfection technique was employed to transfect the miR-152-3p inhibitor to reduce miR-152-3p expression in A2780T cells(miR-152-3p inhibitor group),while the negative control(miR-152-3p NC)group was established.RT-qPCR was used to detect transfection efficiency,and the MTT method,scratch experiment,and flow cytometry were used to investigate the effects of the trans-fecting miR-152-3p inhibitor on survival,migration and apoptosis of A2780T cells.Western blotting was used to detect the protein expressions of Bax and Bcl-2 in A2780T cells.③ Bioinformatics analysis of databases including miRDB,Targetscan,miRWalk,and Starbase predicted the target genes of miR-152-3p that were verified by Western blotting to detect the protein expression of PTEN in A2780T cells of the miR-152-3p inhibitor and miR-152-3p NC groups,and RT-qPCR to detect the PTEN mRNA expression in A2780 and A2780T cells.Then,the lipid-mediated transient transfection technique was used to transfect PTEN siRNA to silence PTEN expression in A2780T cells(PTEN siRNA group).The siRNA negative control(siRNA NC)group was established.RT-qPCR was used to detect transfection efficiency,the MTT method was employed to measure the survival rate and IC50 value,and Western blotting was used to assess the protein expressions of P-gp,MRP1,and ABCG2 in A2780T cells after silencing PTEN expression.RESULTS ①After treatment with PTX,the cell survival rates were decreased in A2780 and A2780T cells(P<0.05),and the resistance index of A2780T cells was 2.8.Compared with A2780 cells,the protein expressions of P-gp and MRP1 and ABCG2 were highly expressed in A2780T cells(P<0.05,P<0.01).② RT-qPCR showed that the expression of miR-152-3p in A2780T cells was higher than that of A2780 cells(P<0.01).Compared with the miR-152-3p NC group,A2780T cell viability(P<0.05,P<0.01)and cell migration capability(P<0.05)were significantly inhibited,while the apoptosis rate increased(P<0.01)in miR-152-3p inhibitor group.Moreover,the protein expression of Bax was increased(P<0.01),but Bcl-2 decreased(P<0.05).③ Bioinformatics analysis suggested that PTEN was a target gene of the miR-152-3p,and the verified results showed that the PTEN protein expression in A2780T cells of the miR-152-3p inhibitor group was lower than that of the miR-152-3p NC group(P<0.05),and PTEN mRNA expression in A2780T cells was higher than that in A2780 cells(P<0.01).After silencing the expression of PTEN in A2780T cells,the cell viability was significantly reduced(P<0.05,P<0.01),while the IC50 value was reduced(P<0.01)compared with the siRNA NC group.In addition,the protein expressions of P-gp,MRP1 and ABCG2 were decreased(P<0.05,P<0.01).CONCLUSION miR-152-3p is highly expressed in A2780T cells,and down-regulation of its expression may inhibit proliferation and migration,prompt apoptosis and reduce the resistance to PTX of A2780T cells,which is made possible by inhibiting expression of its target gene PTEN.