PPARγ在ER+乳腺癌中的表达及对MCF-7细胞生物学行为的影响

Expression of PPARγ in ER+ breast cancer and its effect on biological behavior of MCF-7 cells

目的:探讨过氧化物酶增殖物激活受体γ(peroxidase proliferator activated receptor γ,PPARγ)在雌激素受体(estrogen receptor,ER)+乳腺癌中的表达和意义及对MCF-7细胞生物学行为的影响。方法:采用免疫组织化学法检测77例ER+乳腺癌组织中PPARγ蛋白的表达情况,结合临床病理特征进行分析;运用阳离子脂质体转染法,分别将myc标记的野生型(PPARγWT)及功能区缺失的突变型PPARγ表达质粒(PPARγMUT)转染ER+乳腺癌MCF-7细胞;Western Blot法观察转染后细胞中Wnt通路相关蛋白的表达;运用流式细胞术和CCK-8法检测转染PPARγWT及PPARγMUT对MCF-7细胞周期、增殖活力的影响。结果:PPARγ蛋白的高表达与ER+乳腺癌的腋窝淋巴结转移、组织学分级、TNM分期、Ki-67有关(P<0.05)。外源性转染PPARγWT与转染PPARγMUT比较,能降低MCF-7中的β连环蛋白(β-Catenin)、T细胞受体4(T cell factor-4,Tcf-4)及Wnt通路靶基因c-myc、cyclin D1蛋白量,明显地抑制MCF-7细胞生长和细胞周期进程。结论:PPARγ与ER+乳腺癌发生发展有关,可抑制人乳腺癌细胞的增殖。

Objective:To investigate the expression and significance of peroxidase proliferator activated receptorγ(PPARγ) in estrogen receptor(ER)+ breast cancer and its effect on the biological behavior of MCF-7 cells.Methods:Immunohistochemistry was used to detect the expression of PPAR gamma protein in 77 cases of ER+ breast cancer.Correlations were then analyzed between IHC-assessed level of PPARγ and major clinicopathological variables.The wild-type PPARγ labeled with myc tag (PPARγWT) and deletion mutant PPARγ(PPARγMUT) expression plasmid were then transfected into MCF-7 breast cancer cells by Lipofectamine 2000.Western Blot analysis was used to evaluate the expression of relative proteins of Wnt signaling.Flow cytometry(FCM) and CCK-8 were used to detect the cell cycle and proliferation rate of MCF-7 cells.Results:High expression of PPARγ protein was associated with axillary lymph node metastasis,histological grade,TNM stage and Ki-67 in ER+ breast cancer(P<0.05).Compared with exogenous transfection of PPARγMUT,transfection of PPARγWT could reduce the expression of β-Catenin,T cell factor-4(Tcf-4) and Wnt target genes such as c-myc and cyclinD1 and significantly induce MCF-7 cell proliferation and cell cycle arrest.Conclusions:PPARγ is related to the occurrence and development of ER+ breast cancer and inhibits the proliferation of human breast cancer cells.