α干扰素增强阿霉素诱导的骨肉瘤细胞凋亡

IFN α enhancing doxorubicin-induced apoptosis in human osteosarcoma U2OS cells

目的探讨α干扰素（Interferonα，IFNα）联合化疗药物阿霉素诱导人骨肉瘤U20S细胞凋亡的作用及其机制，为提高骨肉瘤化疗敏感性探索新的治疗方法。方法应用台盼蓝拒染法测定IFNα和阿霉素单用以及联用对U20S细胞的生长抑制作用；Hoechst33258荧光染色检测细胞凋亡形态学变化；Westernblot法检测Caspase-3、PARP的活化；采用Caspase抑制剂Z—VAD—FMK预处理各组细胞，检测该作用是否依赖Caspase。结果IFNα处理24h、48h、72h对U20S细胞无抑制作用，却明显增强阿霉素诱导的生长抑制作用，具有时间依赖性；联合用药72h后U20S细胞出现更为明显的凋亡形态学变化；联合用药组的凋亡关键酶Caspase-3、PARP均发生断裂活化；Caspase抑制剂Z—VAD—FMK预处理明显减弱联合用药引起的生长抑制。结论IFNd通过Caspase依赖性凋亡通路增强阿霉素诱导的骨肉瘤U2OS细胞生长抑制和凋亡，二者联合应用可能成为提高骨肉瘤化疗敏感性的有效途径。

Objective To study the effect of IFN α on doxorubicin-induced apoptosis in human osteosarcoma U2OS cells and its molecular mechanisms. Methods Cell growth inhibition was evaluated using Trypan blue exclusion assay. Apoptosis was studied using Hoechst33258 staining. Activation of Caspase-3 and PARP was detected by Western blot. Cells were pre-treated with Caspase van inhibitor Z-VAD-FMK to determine whether the effect caused by IFN α/doxorubicin was caspase-dependent. Results IFN α treatment for 24 h, 48 h, and 72 h did not induce growth inhibition but greatly enhanced doxorubicin-induced cytotoxicity in U2OS cells. The combination of IFN α and doxorubicin induced more obvious apoptotic morphological changes. Caspase-3 and PARP were cleaved to yield active fragment following IFN α/doxorubicin combination in U2OS cells, compared with other groups. Z-VAD-FMK pre-treatment obviously decreased the growth inhibition caused by IFN α/doxorubicin combination. Conclusions IFN α enhances doxorubicin-induced growth inhibition and apoptosis in human osteosarcoma U2OS cells through caspase-dependent pathway. It implies that rationally combining IFN α with chemotherapy may be a useful strategy for improving the chemosensitivity of osteosarcoma.