关键词: 宫颈癌, 微小RNA375, 增殖, 顺铂耐药, 人类配对盒基因6

Abstract: ObjectiveTo explore the expression of microRNA375 （miR375） and human paired box gene 6 （PAX6） in the cisplatin resistant strain HeLa cisR of cervical cancer and the reversal effect of drug resistance as well as the possible mechanism. 
MethodsThe level of miR375 and PAX6 mRNA in 28 normal cervical tissues and 30 cervical cancer tissues （14 cases of cisplatin sensitive and 16 cases of cisplatin insensitive） and different cisplatin sensitive cells HeLa and HeLa cisR were measured by realtime quantitative PCR （QPCR）. HeLa and HeLa cisR cells were transfected with miR375 analog（mimics） oligonucleotide probe （overexpressed group） and negative control （NC group） by liposome method， and cells without transfection was used as a blank control group. The MTT method was used to detect the proliferation of cells exposure to cisplatin （1， 3， 10， 30， 100 μmol／L） and calculate the median inhibitory concentration （IC50） as to evaluate the sensitivity of cisplatin. Western blotting was used to detect the level of PAX6 protein. The dual luciferase reporter test was used to evaluate the targeting effect of miR375 on PAX6. 
ResultsThe level of miR375 in cervical cancer tissues was lower than that of normal cervical tissue （0714±0341 vs. 1006±0299）， and the level of PAX6 mRNA was higher than that of normal cervical tissue （1855±0928 vs. 1011±0257）. The level of miR375 was negatively correlated with the level of PAX6 mRNA （r=-0416， P＜005）. Compared with chemosensitivity group， the level of miR375 in chemotherapy insensitive group decreased， while the level of PAX6 mRNA increased （P＜005）. The miR375 level of HeLa cisR cells was lower than that of HeLa cells （0365±0098 vs. 1032±0135） and PAX6 mRNA level was higher than that of HeLa cells （3154±0957 vs. 1067±0168） with a statistical significant difference （P＜005）. Compared with other two groups， the miR375 level of the overexpression group was increased after transfection， and the levels of PAX6 protein and mRNA were significantly different （P＜005）. MiR375 overexpression can reduce IC50 of cisplatin （P＜005）， and IC50 of cells with 24 htransfection of miR375 mimics followed by pCMVPAX6 was similar with untransfected cells （P＞005）. 
ConclusionmiR375 is involved in cisplatin resistance of cervical cancer cells through targeting PAX6. MiR375 is expected to become a target for reversing cisplatin resistance in cervical cancer.

Key words: Cervical cancer, MicroRNA375, Proliferation, Cisplatin resistance, Human paired box gene 6