CXC趋化因子受体4通过S期激酶相关蛋白2调控乳腺癌细胞周期的机制

CXC chemokine receptor 4 regulates breast cancer cell cycle through S phase kinase associated protein 2

目的:探讨CXC趋化因子受体4(CXCR4)通过PI3K/Akt和ERK信号通路调控S期激酶相关蛋白2(Skp2)的表达,进而影响乳腺癌细胞周期的机制。方法:利用干扰及过表达技术下调或上调CXCR4的表达后,通过实时定量PCR和蛋白质印迹法检测CXCR4与Skp2调控的关联性;蛋白质印迹法检测CXCR4干扰及过表达后对信号蛋白及Skp2下游相关基因表达的影响;通过碘化丙啶(PI)染色法检测CXCR4、PI3K/Akt通路抑制剂LY294002及ERK通路抑制剂U0126对乳腺癌细胞周期的影响。结果:干扰CXCR4后,Skp2表达下调;过表达CXCR4后,Skp2表达上调。CXCR4可通过对信号蛋白的调控影响Skp2及Skp2下游相关基因的表达。干扰CXCR4后,G_0/G_1期细胞比例增加,S期细胞比例相应减少,CXCR4与LY294002及U0126联合作用对细胞周期的阻断更加明显。结论:CXCR4能够通过对信号蛋白PI3K/Akt及ERK的调控,影响Skp2及Skp2下游相关基因的表达,阻断CXCR4/Akt/Skp2或CXCR4/ERK/Skp2信号通路后可有效诱导细胞周期阻滞,从而抑制乳腺癌细胞的增殖。

Objective： To investigate the effect of CXC chemokine receptor 4 （CXCR4） on cell cycle of breast cancer and its molecular mechanisms. Methods： The expression of CXCR4 and S phase kinase associated protein 2 （Skp2） was detected by real-time fluorescence quantitative PCR （fqRT-PCR） and Western blot in breast cancer cells. The expression of signal proteins and the downstream genes of Skp2 was detected by Western blot. The effect of CXCR4, PI3K/Akt pathway inhibitor LY294002 and ERK pathway inhibitor U0126 on cell cycle of breast cancer was detected by propidium iodide staining. Results： Skp2 was significantly down-regulated in CXCR4-downregulated cells and up-regulated in CXCR4-upregnlated cells. CXCR4 also regulated the expression of Skp2 and other downstream genes by signaling protein. The proportion of cells in G0/G1 phase increased and that in S phase declined in CXCR4-downregulated cell, and the effect was more significant when combined with the use of LY294002 or U0126. Conclusion： CXCR4 can affect cell cycle and inhibit the proliferation of breast cancer cells by regulating Skp2 gene expression through PI3K/Akt and ERK signaling pathway.