| [Background] At present, in the worldwide, ovarian cancer is the leading cause of death in gynecological cancer, not obvious, and the lack of accurate and effective early diagnostic method,and 70%～80% of confirmed patients is already late.So far, in clinical practice, a standard way for the treatment of ovarian cancer is rebulking operation and based on platinum and paclitaxel combined postoperative chemotherapy, however, the 5-year survival rate is only 30% because of the existence of multi-drug resistance in patients with ovarian cancer.Multi-drug resistance become the main obstacle to successful treatment of ovarian cancer, in order to improve the prognosis of ovarian cancer, the study of mechanism of multi-drug resistance becomes the key.In recent years, the mechanism research of the microRNA (microRNAs) to participate in the regulation of tumor cells to chemotherapy tolerance is becoming a hot spot. In terms of ovarian cancer, have been reported related to chemotherapy tolerance of microRNAs including miR-136 , miR-490-3p ,miR-128 , miR-449a ,miR-130b and miR-370, etc.According to recent studies, miR-193a-3p participate in the mechanism regulation of hepatocellular carcinoma to 5-fluorouracil resistance.So far, whether miR-193a-3p takes part in the mechanism regulation of multi-drug resistance in ovarian cancer has not been reported. The study is to screen the most multidrug-sensitive ovarian cancer cell line and most multidrug-resistance ovarian cancer cell line by MTT method, miR-193a-3p expression level was detected in these two kinds of ovarian cancer cell line by qRT-PCR.To discuss the relationship between miR-193a-3p and the multidrug-resistance ovarian cancer cell line and its significance.At the same time, to predict the inhibitor of growth protein 5(ING5) may be a target of miR-193a-3p through microRNAs downstream target forecast website WWW.microRNA.org.Study [9] have shown that ING5 will be able to interact with p300 and p53 in vivo, its expression can induce cell apoptosis in colorectal cancer cells.So far, about the function research of ING5 is still little.Therefore, to detect ING5 expression level in ovarian cancer cell line by Western blot and explore the relationship between ING5 expression and the sensitivity to apoptosis induced by cisplatin in ovarian cancer cell line and its significance.[Objective] To explore the expression of miR-193a-3p in multidrug resistant ovarian cancer cells and its significance.Further,to analyze the expression level of its possible downstream gene,inhibitor of growth protein 5(ING5), in ovarian cancer cell which having different sensitivity to cisplatin.[Methods] MTT method was employed to analyze difference in the sensitivity of ovarian cancer cell line A2780, SKOV-3, HO8910, ES-2 to 5 chemotherapeutic drugs and determine the corresponding 50% inhibiting concentration (IC50) value; The expression level of miR-193a-3p in the most multidrug-sensitive ovarian cancer cell line ES-2 and the most multidrug-resistant cell line SKOV-3 was determined by quantitative real-time polymerase chain reaction(qRT-PCR); MiR-193a-3p mimic was transfected to cell line ES-2 in which miR-193a-3p was expressed at the lowest level,and the transfection efficiency was examined by qRT-PCR.The change in multidrug sensitivity of ES-2 cells after transfection was detected by MTT method. At the same time, to predict the inhibitor of growth protein 5(ING5) may be a target of miR-193a-3p through microRNAs downstream target forecast website WWW.microRNA.org.The expression level of ING5 protein in A2780, SKOV-3, HO8910 and ES-2 cells were determined by Western blot; SiRNA against ING5 was used to silence ING5 gene and the knockdown efficiency was verified by Western blot,and the change of the sensitivity to cisplatin in A2780 cells after transfection was detected by MTT method.[Results]1)The lowest miR-193a-3p expression was obtained in the most multidrug-sensitive ovarian cancer cell line ES-2,but the highest miR-193a-3p expression was observed in the most multidrug-resistant cell line SKOV-3(P<0.01);2) After transfecting miR-193a-3p mimic,ES-2 cells showed more tolerant to (Paclitaxel,Pa;Carboplatin,Kp;Docetaxel,Dt)chemotherapeutic drugs(P<0.01);3)A2780 was the most sensitive cell line to cisplatin, which IC50 value was (0.423 ± 0.020) μg/ml; ES-2 was the most resistant cell line to cisplatin, with IC50 value of (5.280 ± 0.309) lg/ml (P<0.01);4)ING5 protein level was highest in A2780 cells, but lowest in ES-2 cells(P<0.01);5)Knockdown of the ING5 by siRNA significantly reduced the sensitivity of A2780 cells to cisplatin(P<0.01).[Conclusion] MiR-193a-3p might participate in the regulation of multidrug resistance mechanisms in ovarian cancer cells.High expression of ING5 might improve the sensitivity of ovarian cancer cells to cisplatin.ING5 is likely to be affected by other microRNAs rather than the regulation of miR-193a-3p in ovarian cancer cells. |
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