他莫昔芬通过调控ERK1/2信号通路对乳腺癌荷瘤小鼠肿瘤生长的抑制作用及作用机制研究

Tamoxifen inhibits tumor growth in breast cancer tumor-bearing mice by regulating ERK1/2 signaling pathway and its mechanism

目的探究他莫昔芬通过调节细胞外调节蛋白激酶(ERK)1/2途径对乳腺癌荷瘤小鼠肿瘤生长的抑制作用及作用机制。方法通过皮下注射MCF7细胞构建乳腺癌裸鼠模型。将45只荷瘤小鼠按照随机数字表法分为对照组、他莫昔芬组和他莫昔芬+LY3214996组,每组各15只。他莫昔芬组他莫昔芬(25 mg/kg)灌胃,他莫昔芬+LY3214996组他莫昔芬(25 mg/kg)+LY3214996(16 mg/kg)灌胃,对照组给予相同体积的0.9%氯化钠溶液灌胃,各组每日1次,连续21 d。在建模第28天检测各组肿瘤的体积和质量,通过检测Ki67和CyclinD1分析增殖能力,通过TUNEL染色检测凋亡,通过免疫组织化学染色检测CD34评估微血管密度。分析各组ERK1/2蛋白磷酸化水平以及血管内皮生长因子(VEGF)转录和蛋白表达水平。结果他莫昔芬组的肿瘤体积和质量、Ki67和Cyclin D1蛋白水平、微血管密度、ERK1/2蛋白磷酸化水平、VEGF mRNA和蛋白水平显著低于对照组,凋亡指数显著高于对照组,差异均有统计学意义(P<0.05)。他莫昔芬+LY3214996组的肿瘤体积和质量、Ki67和Cyclin D1蛋白水平、微血管密度、ERK1/2蛋白磷酸化水平、VEGF mRNA和蛋白水平显著低于对照组和他莫昔芬组,凋亡指数显著高于对照组和他莫昔芬组,差异均有统计学意义(P<0.05)。结论体内实验表明他莫昔芬通过抑制ERK1/2的磷酸化抑制乳腺癌组织中的血管生成,进而抑制细胞增殖和诱导凋亡。

Objective To explore the inhibitory effect and mechanism of tamoxifen on tumor growth in breast cancer-bearing mice through the regulation of extracellular regulated protein kinases(ERK)1/2 pathway.Methods A nude mouse model of breast cancer was constructed by subcutaneous injection of MCF7 cells.45 tumor-bearing mice were randomly divided into control group,tamoxifen group and tamoxifen+LY3214996 group,each group 15 mouse.Tamoxifen group was given intragastrically tamoxifen(25 mg/kg),tamoxifen+LY3214996 group was given intragastrically tamoxifen(25 mg/kg)+LY3214996(16 mg/kg),and control group was given intragastrically the same volume of normal saline,once a day,for consecutive 21 days.On the 28th day of modeling,the volume and quality of tumors in each group were detected.The proliferation ability was analyzed by detecting Ki67 and CyclinD1.Apoptosis was detected by TUNEL staining.CD34 was detected by immunohistochemical staining to assess microvessel density.The phosphorylation level of ERK1/2 protein and the level of vascular endothelial growth factor(VEGF)transcription and protein expression in each group were tested.Results Tumor volume and mass,Ki67 and Cyclin D1 protein levels,microvessel density,ERK1/2 protein phosphorylation level,VEGF mRNA and protein levels in the tamoxifen group were significantly lower than those in the control group,and the apoptosis index was significantly higher than that in the control group,the differences were statistically significant(P<0.05).Tumor volume and mass,Ki67 and Cyclin D1 protein levels,microvessel density,ERK1/2 protein phosphorylation level,VEGF mRNA and protein levels in the Tamoxifen+LY3214996 group were significantly lower than those in the control group and tamoxifen group,and the apoptosis index was significantly higher than that of the control group and tamoxifen group,the differences were statistically significant(P<0.05).Conclusion In vivo experiments show that tamoxifen inhibits angiogenesis in breast cancer tissues by inhibiting the phosphorylation of ERK1/2,thereby inhibiting cell proliferation and nuclear-induced apoptosis.