人工合成拟Smac融合多肽促低剂量丝裂霉素C诱导膀胱癌细胞凋亡的研究

Apoptosis improvement effect of a synthetic Smac-mimic peptide on bladder cancer cell line T24 with the induction of low-dosage of MMC

目的：探讨人工合成拟Smac融合多肽（SmacN7）对低剂量丝裂霉素C（MMC）诱导的膀胱癌T24细胞凋亡的促进作用。方法：运用固相多肽合成技术人工合成SmacN7细胞可穿透性融合多肽，将0．05mg／ml MMC诱导的膀胱癌T24细胞与50～500μg／L的SmacN7融合多肽共同孵育4～48h，采用Annexin—V荧光染色技术检测肿瘤细胞凋亡情况；应用流式细胞术和MTT比色法检测诱导后T24细胞凋亡率、增殖抑制率与SmacN7的时间和浓度的效应关系。结果：50-500μg／L SmacN7作用4～48h，肿瘤细胞出现典型的凋亡形态学改变，随着SmacN7浓度的增加或药物作用时间的延长，肿瘤细胞凋亡率也增加，12h为5．67％～56．12％，24h为14．54％～65．24％，48h为31．48％～87．23％，同时细胞增殖抑制率出现明显增加，药物作用12h、24h、48h后，增殖抑制率分别为9．58％～63．42％、28．94％～72．3％、44．7％～87．12％。结论：SmacN7能够有效地促进低剂量MMC诱导的膀胱癌T24细胞凋亡，并具有时间和浓度依赖性，为膀胱肿瘤的生物治疗提供了新思路。

Objective：To study the apoptosis improvement effect of a synthetic Smac-mimic peptide （SmacN7） on bladder cancer cell line T24 with the induction of low-dosage of MMC. Methods： Penetrating SmacN7 was synthesized with aid of peptide solid phase synthesis technique. Bladder cancer cell line T24 were incubated with different concentration of SmacN7 （50-500 μg/L） for 4-48 h. The apoptosis was detected by Annexin-V fluorescence staining. The relationship between the percentage of apoptosis and the time and concentration of SmacN7 was assayed by flow cytometry. The inhibitory ratio of cellular proliferation was evaluated by MTT assay. Results： Typical apoptosis morphological changes of tile cells were observed after being treated by 50-500 μg/L SmacN7 for 4-48 h. With the increase of concentration of SmacN7 or the prolongation of the treating time , the percentage of apoptosis increased by 5. 67%-56.12%,14.54%-65.24% and 31.48%-87. 23% when treated for 12 h,24 h,48 h respectively. The proliferation inhibitory ratio of the cancer cells increased notably by 9. 58%-63. 42% ,28. 94% -72.3% and 44.7%-87.12% when treated for 12 h.24 h.48 h respectively. Conclusions： Apoptosis can be effectively improved by Smac N7 on bladder cancer cell line T24 with the induction of low-dosage of MMC and there are time-dependent and dose-dependent relationships between SmacN7 and apoptosis of cancer cells. Synthetic Smac-mimic peptide may be a new strategy of biological therapy for bladder cancer.