Study on the mechanism of MALAT1 targeting miR-142-3p in ovarian cancer chemotherapy resistance / 国际肿瘤学杂志

ABSTRACT

Objective:To study the mechanism of metastasis associated lung adenocarcinoma transcript 1 (MALAT1) targeting microRNA-142-3p (miR-142-3p) in ovarian cancer chemotherapy resistance.Methods:A total of 80 ovarian cancer tissues and paired normal tissues were collected in Shaanxi Provincial People′s Hospital from February 2016 to February 2019. The relative expression levels of MALAT1 and miR-142-3p in ovarian cancer tissues and paired normal tissues were detected by real-time fluorescence quantitative polymerase chain reaction (PCR), and the correlation between MALAT1 and miR-142-3p was analyzed. The effects of abnormal expressions of MALAT1 and miR-142-3p on proliferation and chemotherapy sensitivity of 5-fluorouracil (5-FU) and cisplatin of ovarian cancer Hey cells were verified by CCK-8 assay. Dual luciferase reporter gene experiment was used to detect the targeted relationship between miR-142-3p and MALAT1 (Hey cells were divided into four groups MALAT1 wt, MALAT1 wt+ miR-142-3p mimic, MALAT1 mut, MALAT1 mut+ miR-142-3p mimic). RNA immunoprecipitation assay was use to confirm the binding site of MALAT1 and miR-142-3p.Results:In the ovarian cancer tissues and paired normal tissues, the relative expression levels of MALAT1 were 0.000 52 (0.002 56) and 0.000 47 (0.000 89), with a statistically significant difference ( Z=2.365, P=0.018); the relative expression levels of miR-142-3p were 0.001 19 (0.002 69) and 0.001 61 (0.008 48), with a statistically significant difference ( Z=2.935, P=0.003). The relative expression level of MALAT1 was negatively correlated with miR-142-3p in the ovarian cancer tissues ( r=-0.474, P<0.001). The relative expression level of miR-142-3p in the miR-142-3p mock group was statistically lower than that of MALAT1+ miR-142-3p mimic group (0.004 18±0.001 24 vs. 0.006 51±0.000 28; t=3.174, P=0.017). The relative fluorescence concentrations of MALAT1 wt group and MALAT1 wt+ miR-142-3p mimic group were 2.27±0.86 and 31.10±6.05 respectively, with a statistically significant difference ( t=8.172, P<0.001). After 48, 72 and 96 hours of ovarian cancer Hey cells being transfected with MALAT1 overexpression plasmid, the absorbance ( A) values of cells in the MALAT1 overexpression group were significantly greater than those in the control group (0.522±0.021 vs. 0.433±0.021; 0.644±0.012 vs. 0.544±0.051; 0.887±0.055 vs. 0.698±0.042), with statistically significant differences (all P<0.05). After MALAT1 being overexpressed in Hey cells, at 0.10 ng/μl concentration of 5-FU, the proliferation rate of cells in the overexpression group was significantly faster than that in the control group (0.615±0.036 vs. 0.506±0.042; t=4.432, P=0.002), and the cells at 1.00, 10.00, 100.00 ng/μl concentrations of 5-FU showed the same trends (all P<0.05). At 0.01 ng/μl concentration of cisplatin, the proliferation rate of cells in the overexpression group was significantly faster than that in the control group (0.777±0.015 vs. 0.733±0.039; t=2.355, P=0.023), and the cells at 0.10, 1.00, 10.00, 100.00 ng/μl concentrations of cisplatin showed the same trends (all P<0.05). After miR-142-3p being overexpressed in Hey cells, at 0.10 ng/μl concentration of 5-FU, the proliferation rate of cells in the overexpression group was significantly slower than that in the control group (0.512±0.051 vs. 0.744±0.119; t=4.028, P=0.004), and the cells at 1.00, 10.00, 100.00 ng/μl concentrations of 5-FU showed the same trends (all P<0.05). At 0.10 ng/μl concentration of cisplatin, the proliferation rate of cells in the overexpression group was significantly slower than that in the control group (0.520±0.043 vs. 0.674±0.096; t=3.441, P=0.009), and the cells at 1.00, 10.00, 100.00 ng/μl concentrations of cisplatin showed the same trends (all P<0.05). After ovarian cancer Hey cells being treated with 0.10, 1.00, 10.00, 100.00 ng/μl concentrations of 5-FU and cisplatin, the proliferation rates of cells in the MALAT1 overexpression group, MALAT1+ miR-142-3p group and control group showed statistically significant differences (all P<0.05). Further pairwise comparisons revealed that the proliferation rates of cells in the MALAT1+ miR-142-3p group were significantly slower than those in the MALAT1 overexpression group (all P<0.05). Conclusion:MALAT1 can reduce the sensitivity of ovarian cancer cells to 5-FU and cisplatin by targeted miR-142-3p, leading to chemotherapy resistance of ovarian cancer.