ERK信号通路通过CXCR-4作用于乳腺癌细胞的侵袭转移研究

ERK signaling pathway plays role in the invasion and metastasis of breast cancer through CXCR- 4

目的:ERK信号通路与肿瘤的侵袭转移密切相关,本研究拟阻断ERK通路,检测乳腺癌细胞CXCR-4表达变化,分析ERK信号通路对乳腺癌细胞CXCR-4表达的影响,探讨乳腺癌转移的分子机制。方法:以培养的人乳腺癌MDA-MB-435细胞为研究对象,加入ERK特异性阻断剂PD98059为实验组,加入等量生理盐水为对照组,作用于人乳腺癌MDA-MB-435细胞24 h后,采用Western blotting法检测ERK通路重要因子ERK1/2及磷酸化ERK1/2(p-ERK1/2)表达;采用流式细胞术检测细胞表面CXCR-4表达;采用Transwell侵袭实验观察空白对照组、CXCR-4配体SDF-1α组、ERK通路阻断组和SDF-1α+ERK阻断组细胞的侵袭转移情况。结果 :ERK通路被有效阻断后,CXCR-4表达量明显下调;在趋化因子受体CXCR-4的配体SDF-1α的作用下,细胞侵袭能力提高,而在ERK通路阻断后,细胞侵袭能力明显降低且SDF-1α不能逆转这种降低效应反而具有协同作用。结论:在人乳腺癌MDA-MB-435细胞中,ERK信号通路可能通过上调CXCR-4的表达参与乳腺癌细胞的侵袭和转移。

Objective： ERK signaling pathway is involved in the invading and metastasis of tumor. In this study, we blocked the ERK pathway and observed the change of expression of CXCR-4 in breast cancer cells in order to explore the role of ERK pathway in metastasis mechanism of breast cancer. Methods： The human breast cancer MDA-MB-435 cells were cultured. The ERK specific blocker PD98059 was added into the cells as experimental group and equal volume of normal saline was used as control group. After culture for 24 h, the expression of ERK1/2 and phosphorylation ERK1/2（p-ERK1/2）, which is the important factor of ERK pathway,was detected by Western blotting. And the expression of cell surface CXCR-4 was tested by flow cytometry. The transwell invasion experiment was performed to detect the invasion and metastasis of control group, SDF-1α group（the ligand of chemokine receptor CXCR-4）, ERK pathway blocking group and SDF- 1α ＋ ERK blocking cells.Results： If the ERK pathway was effectively blocked, the expression of CXCR-4 on the surface of the cells would significantly decrease. Under the action of SDF-1α, the cells invasion ability improved. But once ERK pathway was blocked, the cell invasion ability significantly decreased and SDF-1α could not reverse this reduce effect instead of a synergistic effect. Conclusion： ERK pathway may involve in the metastasis of breast cancer MDA-MB-435 cells by up-regulation of the expression CXCR-4.