Objective: To study the effect of miR-342-3p on the chemotherapy sensitivity in triple-negative breast cancer (TNBC).
Methods: Tissue samples were collected from January 2011 to August 2013 samples in Jiangsu Cancer Hospital from a total of 32 triple-negative breast cancer patients with preoperative chemotherapy, with 5 cases of complete response (CR) and 27 cases of partial response (PR). We detected miR-342-3p expression of TNBC with RT-PCR. We transfected has-miR-342-3p mimic and inhibitor into breast cancer cell lines MDA-MB-231 by lipofection transfection and set up negative control mim-NC and inhi-NC. Group of mimic, mim-NC, inhibitor and inhi-NC were cultivated with 2 μmol /L paclitaxel, cisplatin or 4 μmol/L doxorubicin for 48 h. The cell growth rates were measured by CCK8 reagent kit, and the cell apoptosis rate by flow cytometry.
Results: The expressions of miRNA-342-3p in TNBC tissue of CR were higher than those of PR. The cell growth rates of mimic were lower and cell apoptosis rates were higher than those of min- NC after cultivating with paclitaxel or cisplatin for 48 h, with significant difference (P<0.05). The cell growth rates of inhibitor were higher and cell apoptosis rates lower than those of inhi-NC after cultivating with paclitaxel or cisplatin 48 h, with significant difference (P<0.05). The cell growth and cell apoptosis rates of mimic and inhibitor had no difference with those of mim-NC and inhi- NC after cultivating with doxorubicin 48 h (P>0.05).
Conclusion: TNBC with high expression of miR-342-3p are more sensitive to chemotherapy. miRNA-342-3p may regulate the sensitivity of breast cancer cell line MDA-MB-231 to chemotherapy drugs paclitaxel and cisplatin, but can not affect the chemotherapy sensitivity of doxorubicin.