论文部分内容阅读
[目的]研究镉对人乳腺癌MCF-7细胞增殖及雌激素受体(estrogen receptor,ER)蛋白表达水平的影响及其可能机制.[方法]用1×10-6-、1×10-7、1×10-8、1×10-9、1×10-10、1×10-11 mol/L的17β-雌二醇(后称雌激素)培养不同来源的A、B两株MCF-7细胞4d,应用CCK8法筛选敏感细胞株并确定雌激素促细胞增殖作用最强的浓度.用1×10-6、1×104、1×10-s、1×10-9、10-10、1×10-11 mol/L的镉溶液染毒敏感细胞株,确定镉促进细胞增殖的最大浓度.设置阴性对照组(去雌激素培养液)、实验组(1×10-s mol/L镉)、阳性对照组(1×10-9 mol/L雌激素),通过克隆形成实验检测镉对MCF-7细胞集落形成能力的影响.利用ER抑制剂(ICI182780)初步探讨镉致细胞增殖的可能机制,增设实验抑制剂组(1×10-8 mol/L镉+1×10-7 mol/L ER抑制剂)、阳性抑制剂组(1×10-9 mol/L雌激素+1×10-7mol/LER抑制剂),通过CCK8法、流式细胞术和Western blot分别检测各组的细胞增殖率、细胞周期S期比例和ER表达水平. [结果]实验所用B株MCF-7细胞为雌激素敏感细胞株,且当雌激素浓度为1×10-9 mol/L时,对MCF-7细胞的促进增殖作用[(203.55±36.65)％]最大(P＜0.001).与阴性对照组(100％)相比,1×10-8～1×10-10 mol/L镉溶液可促进MCF-7细胞增殖[(163.78±31.90)％～(176.88±10.06)％](P＜0.001).1×10-8 mol/L镉可促进细胞集落形成(P＜0.05),增加细胞S期比例(P＜0.001),提高细胞ER蛋白表达水平(P＜0.001).与实验组相比,加入ER抑制剂能够抑制镉对MCF-7细胞的促增殖作用[由(135.17±23.96)％降至(107.66±7.64)％](P＜0.01),抑制镉诱导的细胞S期比例增加[由(24.17±0.53)％降至(12.36±0.43)％](P＜0.001),拮抗镉诱导的ER表达增加[由(56.19±3.67)％降至(38.84±1.04)％](P＜0.05).[结论]镉可以促进人乳腺癌细胞MCF-7增殖和ER表达,这种作用可被ER抑制剂所抑制,提示镉可能具有雌激素样作用.“,”[Objective] To investigate the effect and potential mechanism of cadmium (Cd) on the proliferation of human breast cancer MCF-7 cells and the expression of estrogen receptor (ER).[Methods] A and B strains of MCF-7 cells were treated with 17β-estradiol (hereinafter referred to as estrogen) at 1 × 10-6,1 × 10-7,1 × 10-8,1 × 10-9,1 × 10-10,and 1 × 10-11 mol/L,respectively,for 4d.CCK8 assay was employed to detect a susceptible MCF-7 cell strain and to identify the concentration of estrogen promoting maximum cell proliferation.Then,the susceptible MCF-7 cell strain was treated with 1 × 10-6,1 × 10-7,1 × 10-8,1 × 10-9,1 × 10-10,and 1 × 10-11 mol/L cadmium solution,respectively,to identify the concentration of cadmium promoting maximum cell proliferation.We set a negative control group (medium without estrogen),an experimental group (1 × 10 mol/L cadmium),and a positive control group (1 × 10-9mol/L estrogen) to evaluate colony formation ability by clonogenicity assay.Additionally,we set an experimental inhibitor group [1 × 10-8 mol/L Cd+1 × 10-7 mol/L ER antagonist (ICI 182780)] and a positive inhibitor group (1 × 10-9 mol/L estrogen+ 1 × 10-7 mol/L ER antagonist) to detect cell proliferation,the ratio of S phase cells,and the expression level of ER by CCK8,flow cytometry,and Western blot,respectively.[Results] The MCF-7 cells of strain B were estrogen sensitive cells,and the 1 × 10-9 mol/L estrogen treatment induced the maximum cell proliferation [(203.55 ± 36.65)％].Compared with the negative control group (100％),1 × 10-8-1 × 10-10 mol/L cadmium significantly promoted proliferation of MCF-7 cells [(163.78 ± 31.90)％-(176.88 ± 10.06)％] (P ＜ 0.001).Besides,1 × 10-8 mol/L cadmium treatment promoted colony formation of MCF-7 cells (P ＜ 0.05),increased the ratio of S phase cells (P ＜ 0.001),and elevated ER protein expression level (P＜0.001).Compare with the experimental group,ER antagonist suppressed the effect of cadmiium on proliferation of MCF-7 cells [from (135.17 ± 23.96)％ to (107.66 ± 7.64)％] (P＜0.01),reduced the ratio of S phase cells [from (24.17 ± 0.53)％ to (12.36 ± 0.43)％] (P ＜ 0.001),and down-regulated ER protein expression level [from (56.19 ± 3.67)％ to (38.84 ± 1.04)％] (P＜0.05).[Conclusion] Cadmium can promote proliferation and ER expression of breast cancer MCF-7 cells,and the effect can be inhibited by ER antagonist,indicating estrogen-like effect of cadmium.