CXCR4的抑制性多肽对乳腺癌细胞CXCR4和HER-2表达及HERCEPTIN药物敏感性的影响

THE EFFECT OF INHIBITORY POLYPEPTIDE OF CXCR4 ON THE EXPRESSION OF CXCR4 AND HER-2 OF BREAST CANCER CELLS AND THE SENSITIVITY OF HERCEPTIN

目的探讨CXCR4抑制性多肽对人乳腺癌细胞株SKBR3膜受体HER-2和CXCR4的蛋白表达及其对Herceptin药物敏感性的影响。方法抑制性多肽、Herceptin单独或联合处理乳腺癌SKBR3细胞24、48h后,用MTT法观测SKBR3细胞的增殖抑制效应;Westernblot和免疫组化法检测SKBR3细胞中CXCR4和HER-2蛋白表达;RT-PCR检测HER-2、CXCR4mRNA的表达,流式细胞仪检测细胞周期的变化。结果多肽和Herceptin可不同程度地下调人乳腺癌细胞SKBR3中CXCR4和HER-2的蛋白表达。多肽对细胞生长抑制不明显,与Herceptin联合用药后,生长抑制率高于对照组和Herceptin单独用药组(P<0.001),48h生长抑制率为57.94%±5.3,且呈时间依赖(P<0.05),Herceptin单独作用SKBR3细胞,细胞周期阻滞于G0/G1期,并且S期的比例减少,与多肽联合作用后,细胞周期又进一步阻滞于G2/M期,S期细胞进一步降低。结论抑制性多肽能不同程度地下调膜受体HER-2和CXCR4的表达,提高人乳腺癌细胞株SKBR3对Herceptin药物的敏感性。

Objective To study the effect of inhibitory polypeptide CXCR4 on human breast cancer cell line SKBR3 and observe the protein expression of membrane receptor HER-2 and CXCR4 and the effect of the sensitivity of SKBR3 to herceptin. Methods The breast cancer cells of SKBR3 were treated with inhibitory polypeptide and herceptin alone or together for 24h, 48h. Western bloting and immunobistochemistry were used to detected the protein expression of CXCR4 and HER-2 in SKBR3 cells , The expression of HER-2 and CXCR4 mRNA in SKBR3 cells were assessed by RT-PCR. FCM was used to test the cell cycle of SKBR3 cells. The inhibitory effect of the cells was determined by MTT. Results Inhibitory polypeptide of CXCR4 and herceptin could down-regulate the expression of HER-2 and CXCR4 in SKBR3 cells in different degree. The growth of SKBR3 cells could not be inhibited by polypeptide alone obviously, but could be significantly inhibited by polypeptide combined with herceptin in a time-dependent manner （P〈 0.05） . The inhibitory rates reached 57.94±5.3% after 48 hours, much higher than the control group and the herceptin group （P〈0. 001）, herceptin arrested cells at G1 phase, and decreased the rate of S phase When combined with polypeptide , the cells were further arrested at G2 phase and the rate of S phase was decreased dramatically. Conclusion Inhibitory polypeptide can down-regulate the expression of membrane receptor HER-2 and CXCR4 on breast cancer cells SKBR3 , and increase the sensitivity of breast cancer cells SKBR3 to herceptin.