光动力疗法对人乳腺癌细胞MDA-MB-231凋亡的影响

目的探讨光动力疗法(PDT)对人乳腺癌细胞凋亡的影响。方法以人乳腺癌细胞株MDA-MB-231为研究对象,以血卟啉衍生物(HpD)为光敏剂,以630 nm波长激光为光源,采用连续照射的方式。将不同浓度HpD染色的MDA-MB-231细胞,照射不同剂量的激光后,用MTT法测定其A492值,选择最佳作用参数;电镜观察PDT作用后不同时间的细胞凋亡情况,并采用免疫组化方法检测促凋亡蛋白Bax和抗凋亡蛋白Bcl-2的表达情况。结果随着PDT作用后时间的延长,细胞凋亡现象越明显;Bax蛋白表达无明显变化(P>0.05),而Bcl-2蛋白表达自PDT后6 h起显著下降(P<0.01),PDT后6 h Bax/Bcl-2比值依次递增,且有统计学意义(P<0.05)。结论光动力疗法可诱导人乳腺癌细胞发生凋亡,其机制可能与Bax和Bcl-2蛋白表达的比值有关。

Effect of photodynamic therapy on apoptosis in human breast cancer cell line MDA-MB-231

Objective To study the effect of photodynamic therapy(PDT) on apoptosis in human breast cancer line MDA-MB-231.Methods The cells were incubated with a photosensitizer(hemoporphyrin derivative,HpD) with different concentrations,and then were irradiated for 10min using the successive laser of different dosages at 630nm.Cell viability was measured with MTT,and cell apoptosis was identified morphologically by electron microscope.Expressions of Bax and Bcl-2 proteins were detected by immunocytochemistry.Results Cell apoptosis became more obvious as time prolonged after PDT.No alteration in the expression of Bax was observed at the different times after PDT(P>0.05).However,the expression of Bcl-2 was significantly decreased 6h after PDT(P<0.01),and the ratio of Bax/Bcl-2 expression was markedly increased as time prolonged after PDT(P<0.05).Conclusion Photodynamic therapy can induce cell apoptosis of human breast cancer cells,and the mechanism may be associated with the ratio of Bax/Bcl-2 expressions.