姜黄素对乳腺癌MDA-MB-231细胞株放射增敏作用的研究

Effect of curcumin on radiosensitization of breast cancer cell MDA-MB-231

目的姜黄素(curcumin)能有效增强放射线对乳腺癌的作用,但其作用机制尚不明朗。该文探讨姜黄素对人乳腺癌MDA-MB-231细胞放射增敏的作用机制。方法对数生长的乳腺癌MDA-MB-231细胞,分成对照组、姜黄素组、照射组及联合组,使用流式细胞术(flow cytometry,FCM)检测细胞凋亡率;克隆形成实验检测放射增敏作用;蛋白免疫印迹法(Western blotting)检测Akt及pAkt蛋白表达。结果联合组凋亡率显著高于照射组﹝(28.49±4.66)%vs(12.41±4.98)%﹞(q=20.07,P<0.01);与照射组比较,克隆形成实验的放射敏感性指标标准阈剂量(Dq)、平均致死剂量(Do)、2 Gy存活分数(SF2)均明显降低,放射增敏比(SERDO)为1.293;各组间的Akt蛋白差异没有统计学意义(F=3.467,P=0.051),与对照组比较,单纯照射能提高pAkt的蛋白表达(q=4.71,P<0.05),而姜黄素可以抑制pAkt蛋白的表达(q=4.11,P<0.05),两者联用后pAkt蛋白表达较单纯照射组显著降低(q=7.36,P<0.01)。结论姜黄素可以增强射线对乳腺癌MDA-MB-231细胞的敏感性,其机制可能与姜黄素阻断PI3K/Akt信号通路中Akt磷酸化有关。

【Objective】 To find the effect and mechanism of curcumin on the radiosensitivity of human breast cancer cells. 【Methods】 Breast cancer cell line in the logarithmic phase was divided into the control group, curcumin group, radiation group and combination group（radiation ＋ curcumin）. Apoptosis rate was ana- lyzed by flow cytometry（FCM）. The radiosensitization effect was detected by clone experiment. The expressions of Akt and pAkt protein were detected by Western blotting. Results： Apoptosis rate in combination group was higher than radiation group 〔（28.49 ± 4.66） % vs（12.41 ± 4.98） %〕（q =20.07, P 0.01）. Compared with radia- tion group, the values of Dq, Do and SF2 decreased significantly in combination group, and the SERDO was 1.293 by the clonogenic assay. The expression of Akt protein in each group was not significantly（F =3.467, P =0.051）. The expression of pAkt protein was significantly higher than control group（q =4.71, P 0.05）, while curcumin inhibited the expression of pAkt（q =4.11, P 0.05）, and the expression of pAkt was significantly downer compare with radiation group（q =7.36, P 0.01）. 【Conclusion】 Curcumin can enhance the radiosensi- tivity in breast cancer cell, that is about the down-regulation of the changer Akt to pAkt in the PI3K/Akt.