CXCL12/CXCR4激活Akt通路降低前列腺癌干细胞多西紫杉醇敏感性的研究

Study on CXCL12/CXCR4 promoting prostate cancer stem cells docetaxel resistance via phosphorylating Akt

目的观察前列腺癌干细胞中趋化因子受体-4(CXCR4)的表达,探索CXCR4影响癌干细胞化疗敏感性的机制。方法流式细胞仪检测细胞表面CXCR4阳性率;MTS检测不同剂量多西紫杉醇对细胞活力的影响,绘制量效曲线,计算多西紫杉醇IC50;分别使用CXCL12或者抗CXCR4抗体激活或者阻断CXCR4后,检测多西紫杉醇化疗后前列腺癌干细胞细胞活力;蛋白免疫印迹法测p-Akt、Akt蛋白的表达变化。结果前列腺癌干细胞中CXCR4阳性率为71.37±4.03%,非癌干为19.08±1.86%,二者有显著差异;使用多西紫杉醇化疗时,癌干细胞IC50为7.5μM,非癌干细胞IC50为0.6μM,癌干细胞耐多西紫杉醇能力明显强于非癌干细胞;CXCL12激活CXCR4后,细胞活力为92.15±3.44%;抑制CXCR4后,细胞活力为68.46±4.16%;对照组细胞活力为70.24±3.52%;使用CXCL12激活CXCR4后,Akt磷酸化水平显著增加,抗CXCR4抗体可以阻断Akt磷酸化过程。结论 CXCL12/CXCR4可通过激活Akt下调前列腺癌干细胞对多西紫杉醇敏感性,这可能是前列腺癌干细胞化疗不敏感的重要机制之一。

Objective To explore the expression of chemokine （C-X-C motif） receptor 4 （CXCR4） in prostate cancer stem cells （PCSCs）, and the role of CXCR4 in PCSCs docetaxel resistance. Methods FACS was employed to measure the expression of CXCR4 on PCSCs and non-PCSCs surfaces; MTS was conducted to evaluate the cell viability under different concentration of docetaxel, and IC50 was calculated according to the dose-effect curves; CXCL12 or antibody against CXCR4 were used before docetaxel was added into the medium, and cell viability was measured by MTS; Western blotting was conducted to test the activation of signaling pathways. Results PCSCs cells contained 74.24% CXCR4 positive cells, while only 20.39% cells were CXCR4 positive in non-PCSCs （P〈0.05）; IC50 of docetaxelwas 7.5 μM in PCSCs, and 0.6 μM in non-PCSCs; 72 hours after docetaxel treatment, cell viability was 92.15±3.44% in CXCL12 group, 68.46±4.16% in anti-CXCR4 group, and 70.24±3.52% in negative control group; CXCL12 could significantly increase Akt phosphorylation in PCSCs. Conclusion CXCL12 activate the Akt signaling pathway via CXCR4 on PCSCs, inducing the docetaxel resistance of PCSCs, which may be one of the important mechanisms underlying the desensitization of docetaxel in PCSCs.