CXCL12受体抑制剂调控三阴性乳腺癌放射治疗的敏感性

The effect of CXCR4 inhibitor on radiosensitization of triple negative breast cancer

目的探讨趋化因子12(CXCL12)受体CXCR4抑制剂AMD3100对人乳腺癌MDA-MB-231细胞裸鼠移植瘤的放射增敏效应及其作用机制。方法建立人乳腺癌裸鼠移植瘤模型,并随机分为4组:对照组、AMD3100处理组、放射治疗组和联合治疗组(AMD3100+放疗);称量肿瘤的重量并测量移植瘤的体积,计算放射增敏比,绘制肿瘤生长曲线;实时荧光定量PCR(QPCR)检测CXCR4和表皮生长因子受体(EGFR)基因表达;蛋白质印迹法检测CXCR4、EGFR和基质金属蛋白酶-9(MMP-9)蛋白表达。结果经统计CXCR4抑制剂AMD3100的放射增敏比为1.45。QPCR结果显示,与对照组比较,CXCR4和EGFR基因的相对表达量在AMD3100处理组、放射治疗组及联合治疗组分别下调60%、45%、82%和56%、48%、73%,差异有统计学意义(P<0.05)。单纯AMD3100治疗或者放射治疗均能使CXCR4、EGFR表达下调(P<0.05),联合治疗较单纯AMD3100治疗和放疗更能显著地抑制CXCR4和EGFR的表达(P<0.05)。Western blotting结果显示,与对照组比较,CXCR4、EGFR及MMP-9在AMD3100处理组、放射治疗组及联合治疗组中的蛋白相对表达量均下调(P<0.05)。AMD3100与放疗均可抑制CXCR4、EGFR及MMP-9的表达,两者联用较单一治疗的效果更加显著(P<0.05)。结论 CXCR4抑制剂AMD3100可增强乳腺癌裸鼠移植瘤的放射敏感性,其机制可能是通过下调CXCR4、EGFR和MMP-9的表达而发挥作用。

Objective To investigate the radiation sensitivity of chemokine 12（CXCL12） receptor CXCR4 inhibitor AMD3100 on xenograft tumor of breast cancer of MDA-MB-231 cells in nude mice and the underlying mechanism.Methods Human breast cancer xenograft model on nude mice was established successfully,and the mice were divided into 4 groups：control group,AMD3100 treatment group,radiation group and combination group（AMD3100 ＋ radiation）,9 mice each group.The size and weight of xenograft tumor were measured,the radiosensitization enhancement ratio was calculated and the xenograft tumor growth curve was depicted.The quantitative real-time PCR（QPCR） was used to detect the expression of CXCR4 and epidermal growth factor receptor（EGFR）.Western blotting was used to detect the protein expression of CXCR4,EGFR and matrix metalloproteinases-9（MMP-9）.Results The radiosensitization enhancement ratio was 1.45.Compared with the control group,the gene relative expression of CXCR4 and EGFR in AMD3100 treatment group,radiotherapy group and combination group was down-regulated by 60%,45%,82% and 56%,48%,73%,and the difference was statistically significant（P 0.05）.The result by QPCR showed that both AMD3100 and radiotherapy could inhibit the expression of CXCR4 and EGFR（P 0.05）,while AMD3100 and radiation combination could better inhibit the expression of CXCR4 and EGFR when compared with the AMD3100 single treatment group and radiotherapy group（P 0.05）.The result of Western blotting showed that AMD3100 or radiotherapy could inhibit the expression of CXCR4,EGFR and MMP-9,AMD3100 and radiotherapy combination inhibited the expression of the three proteins more significantly（P 0.05）.Conclusion AMD3100 can enhance the radiosensitivity in nude mice xenografts of breast cancer,and the mechanism involves the down-regulation of CXCR4,EGFR and MMP-9.