Abstract: Abstract: Objective To investigate the effect of down-regulation of long noncoding RNA (lncRNA) human ovarian cancer-specific transcripts 2 (HOST2) expression on the sensitivity of human ovarian carcinoma SKOV3 cells to cisplatin, and its possible mechanism thereof. Methods SKOV3 cells were cultured in vitro, and the logarithmic growth phase cells were divided into blank control (BC) group, negative control (NC) group and siRNA group. The siRNAs targeting lncRNA HOST2 and negative control were transfected into SKOV3 cells of siRNA group and NC group by cationic liposome, the BC group was not transfected. The expression of lncRNA HOST2 was detected by qPCR, and the protein expressions of Akt, pAkt (S473), p-Akt (S380) and Bcl-2 were detected by Western blot assay. The cell survival was detected by CCK-8 after SKOV3 cells were treated by different concentrations of cisplatin (0、20、40、60、80、100 μmol/L) and the cisplatin half inhibitory concentration (IC50) was calculated. The apoptotic rate after treatment with 20 μmol/L cisplatin was checked by flow cytometry. Results Compared with BC group and NC group, the expression of lncRNA HOST2 and the protein expressions of p-Akt (S473), p-Akt (S380) and Blc-2 decreased in siRNA group (P＜0.05). There was no significant difference in the expression of Akt protein between three groups (P＞0.05). The cell survival rates all decreased with the increased cisplatin concentration, and values of IC50 were (59.58±5.97), (51.42±5.22) and (39.75±5.31)μmol/L in BC group, NC group and siRNA group. The apoptotic rate was significantly higher in the siRNA group (12.42%±1.46%) than that in the BC group (7.53%±1.25%) and the NC group (8.16%±1.31%). Conclusion The downregulation of lncRNA HOST2 expression could enhance the cisplatin sensitivity in human ovarian cancer SKOV3 cells, and its mechanism is related to the inhibition of PI3K/Akt pathway-related protein expressions.

Key words: ovarian neoplasms, RNA, long noncoding, ovarian cancer-specific transcripts 2, cisplatin, PI3K/Akt
pathway