Effects of miR-143 overexpression on proliferation, apoptosis, EGFR and downstream signaling pathways in PC9/GR cell line.

OBJECTIVE

The functions of microRNAs in the regulation of apoptosis in non-small cell lung cancer (NSCLC) and the application in the therapeutical treatments were intensively studied. However, whether overexpression of miR-143 in lung cancer cells will affect the cell behaviors, such as proliferation or some underlying pathway, is largely unknown. This study aimed to examine the effect of miR-143 in PC9/GR cell line on the proliferation, apoptosis, EGFR and downstream signal pathways.

MATERIALS AND METHODS

The non-small cell lung cancer (PC9/GR) cells were treated with concentration-increased gefitinib to acquire gefitinib resistance. Then, the acquired gefitinib-resistance cells were divided into 3 groups, blank control group (BC group), negative control group (NC group), and miR-143 transfected group (miR-143 group). miR-143 mRNA was detected by quantitative PCR. The proliferation was detected by CCK-8. The cell apoptosis was determined by flow cytometry. The expression of EGFR and downstream signal pathway factors of p-EGFR, AKT, p-AKT, ERK1/2 and p-ERK1/2 were detected by Western blot.

RESULTS

The cell proliferation in miR-143 transfected group was significantly suppressed compared with BC and NC group, while the apoptosis was dramatically increased. The p-EGFR, p-AKT, p-ERK1/2 protein expression was significantly inhibited.

CONCLUSIONS

These results demonstrated that overexpression of miR-143 downregulated cell proliferation, promoted the apoptosis, and suppressed the phosphorylation of EGFR, AKT and ERK1/2; thus, miR-143 may play a role in treatment of NSCLC to enhance therapeutic efficacy.