RSK4与Ki-67、cyclin D1、CXCR4、E-cadherin在乳腺癌裸鼠移植瘤中的相关性研究

Correlations of RSK4 expression with Ki-67,cyclin D1,CXCR4 and E-cadherin levels in an in vivo tumor model of breast cancer

目的分析乳腺癌裸鼠移植瘤中核糖体S6蛋白激酶4(ribosomal protein S6 kinase 4,RSK4)与Ki-67、cyclin D1、CXCR4、E-cadherin表达的相关性,进一步探讨RSK4在乳腺癌发展中的作用机制。方法将转染si RNA(RSK4-RNAiLV)的MCF-7细胞(实验组)、转染si RNA(NC-GFP-LV)的MCF-7细胞(阴性对照组)和未转染的MCF-7细胞(空白对照组)分别接种至裸鼠乳腺脂肪垫下,建立乳腺癌裸鼠移植瘤模型,剥离裸鼠移植瘤;采用免疫组织化学法检测移植瘤标本中增殖因子RSK4、Ki-67、cyclin D1及侵袭因子CXCR4、E-cadherin蛋白的表达。结果实验组RSK4、E-cadherin蛋白的表达水平分别为(3.2±0.5)%、(28.2±0.7)%,明显低于空白对照组的(36.7±3.4)%、(51.7±4.2)%和阴性对照组的(61.1±5.1)%、(49.2±3.8)%,差异有统计学意义(F=56.79,61.89,P<0.05)。实验组Ki-67、cyclin D1、CXCR4蛋白的表达水平分别为(67.8±5.8)%、(61.7±4.6)%、(56.3±3.9)%,明显高于空白对照组的(34.5±1.4)%、(29.7±2.5)%、(30.7±3.1)%和阴性对照组的(29.8±1.9)%、(35.7±4.6)%、(28.5±3.7)%,差异有统计学意义(F=45.24,52.16,61.24,P<0.05)。相关性分析显示,RSK4与Ki-67、cyclin D1、CXCR4表达呈负相关(r=-0.857,-0.826,-0.867,P<0.001),与E-cadherin表达呈正相关(r=0.879,P<0.001)。结论RSK4可能通过调节CXCR4、Ki-67、Cyclin D1和E-cadherin肿瘤相关因子的表达,在乳腺癌在乳腺癌生长及转移过程中发挥作用。

Objective To investigate the relationship between RSK4 expression and Ki-67,cyclin D1,CXCR4 and E-cadherin levels in an in vivo tumor model of breast cancer in order to explore the mechanism of breast cancer development. Methods The experimental group of nude mice was subcutaneously injected with MCF-7 cells transfected with siRNA （RSK4-RNAi-LV）,while the negative control group was subcutaneously injected with MCF-7 cells transfected with siRNA （NC-GFP-LV）, and a blank control group was subcutaneously injected with MCF-7 cells alone. Expression of RSK4, Ki-67, cyclin D1, CXCR4 and E-cadherin in samples of transplanted tumors was observed by immunohistochemistry. Results Levels of RSK4 and E-cadherin protein were 32±0.5% and 28.2±0.7% in the experimental group, which was significantly lower than in the blank control group （36.7±3.4%,51.7±4.2%） and negative control group （61.1±5.1%,492±3.8%） （F=56.79 and 61.89,P〈0.05）. Similar,expression levels of Ki-67,eyelin D 1, and CXCR4 in the experimental group were, respectively, 67.8±5.8%, 61.7±4.6%, and 56.3±3.9% ,which were significantly higher than in the blank control group（34.5±1.4% ,29.7±2.5%, 30.7±3.1%） and the negative control group （29.8±1.9%,35.7±4.6%,28.5±3.7%） （F=45.24,52.16,and 61.24,P〈0.05）. RSK4 protein expression showed a significant negative eon＇elation with Ki-67 （r=-0.857, P〈0.001 ）, cyelin D1 （r=-0.826, P〈0.001 ） and CXCR4 （r=-0.867,P〈0.001）. RSK4 protein expression showed a significant positive correlation with E-cadherin （r=0.879,P〈0.001）. Conclusions RSK4 knockdown may affect the expression of tumor proliferation factor and invasion factor, promoting the proliferation and metastasis of breast cancer cells. RSK4 may regulate genes in a way that promotes breast cancer cell proliferation and invasion,including up- regn-lation of CXCR4, Ki-67, and CyelinD 1, as well as down-regnlation of E-cadherin.