镉对MCF-7细胞雌激素受体和miRNA表达作用研究

Effects of cadmium on the expression of estrogen receptor and miRNA in MCF-7 cells

目的研究镉对人乳腺癌细胞株MCF-7细胞雌激素受体(ER)和miRNA-155、miRNA-200c表达的影响。方法取对数生长期MCF-7细胞,随机分为无氟维司群(ICI)组和ICI组。无ICI组细胞分别采用终浓度分别为0.0、2.5、5.0、10.0μmol/L的氯化镉染毒24 h;ICI组细胞在采用终浓度为1.0μmol/L的ICI预处理12 h后,分别采用终浓度分别为0.0、2.5、5.0、10.0μmol/L的氯化镉染毒24 h。采用四甲基偶氮噻唑蓝(MTT)法检测细胞增殖率,流式细胞术检测细胞凋亡率,免疫印迹法检测ERα和ERβ相对表达水平,实时荧光定量聚合酶链式反应法检测miRNA-155和miRNA-200c相对表达水平。结果当予浓度为2.5、5.0、10.0μmol/L的氯化镉染毒时,MCF-7细胞增殖率均低于无予氯化镉染毒MCF-7细胞(P<0.05);ICI组MCF-7细胞增殖率均低于无ICI组(P<0.05)。当予浓度为2.5、5.0、10.0μmol/L的氯化镉染毒时,与同组无予氯化镉染毒的MCF-7细胞比较,无ICI组MCF-7细胞凋亡率均上升(P<0.05),ERα、ERβ、miRNA-155和miRNA-200c相对表达水平均升高(P<0.05);而ICI组MCF-7细胞的增殖率均下降(P<0.05),凋亡率均上升(P<0.05),ERα、ERβ相对表达水平均升高(P<0.05),miRNA-155和miRNA-200c相对表达水平均下降(P<0.05)。当无予氯化镉染毒时,与无ICI组比较,ICI组MCF-7细胞凋亡率升高(P<0.05),ERα和ERβ相对表达水平均下降(P<0.05),miRNA-155和miRNA-200c相对表达水平均高于相同染毒剂量的无ICI组(P<0.05);当予浓度为2.5、5.0、10.0μmol/L的氯化镉染毒时,与相同染毒剂量的无ICI组比较,ICI组MCF-7细胞凋亡率和ERα、ERβ、miRNA-155、miRNA-200c的相对表达水平均下降(P<0.05)。结论镉可能通过ER信号通路介导MCF-7细胞miRNA的表达增强和凋亡诱导作用。

Objective To study the effects of cadmium on the miRAN-200c in hmnan breast cancer MCF-7 cells. Methods expression of estrogen reeeptor （ER） and miRAN-155, MCF-7 cells in logarithmic growth phase were randomly divided into fulvestrant （ICI182780, ICI） group and non-ICl group. The non-ICI group was treated with cadmium chloride （CdC12 ） at the final concentrations of 0. 0, 2. 5, 5.0 and 10. 0 μmol/L for 24 hours. The ICI group was pretreated at a concentration of 1.0 μmol/L for 12 hours, and then treated with CdC12 at the final concentrations 0. 0, 2. 5, 5.0 and 10.0 μmol/L for 24 hours. The cell proliferation activity was measured by methyl thiazolyl tetrazolium assay. Flow cytometry was used to measured cell apoptosis. Western blot was applied to measure the relative expression of ERa and ERβ protein, and the relative expression of miRNA-155 and miRNA-200c were detected by real-time fluorescence quanlilative polymerase chain reaction. Results The proliferation rates of MCF-7 cells in 2. 5, 5.0 and 10. 0 μmol/L CdC12 groups were significantly decreased than the 0. 0μmol/L CdC12 group （P 〈 0. 05）. The proliferation rate in 1CI group was lower than that of the non-lCI group （ P 〈 0. 05）. When CdC12 concentration was 2. 5, 5.0 and I0. 0μmol/L, the apoptosis rate of MCF-7 cells in non-ICl group increased compared with those cells without exposure to CdCL （ P 〈 0. 05 ）. The relative expression of ERa, ERβ, miRNA-155 and miRNA-200e increased （P 〈 0. 05）. The proliferation of MCF-7 cells in ICI group decreased （ P 〈 0. 05 ） , and the relative apoptosis rate increased （ P 〈 0. 05 ） ; and the relative expression of ERa and ERβ increased （P 〈 0. 05） , the relative expression of miRNA-155 and miRNA-200c decreased （ P 〈 0. 05 ）. When treated without CdCl2, the apoptosis rate of the IC1 group increased compared with non-ICI group （P 〈 0. 05 ）, the relative expression of ERoL and ERβ decreased （ P 〈 0. 05 ） . and the relative expression of miRNA-155 and miRNA-200c wereincreased （P 〈 0. 05）. When CdC12 concentration was 2. 5, 5.0 and 10. 0μmol/L, the apoptosis rate and the relative expression of ERa, ERβ, miRNA-155 and miRNA-200c decreased compared with the non-ICI group treated with same dose CdC12 （P 〈 0. 05）. Conclusion Cadmium can induce cell apoptosis and increase expression of miRNAs through the ER signaling pathway.