MPPa-photodynamic Therapy Induces Apoptosis In Cisplatin-resistance Cancer Cells

Background and objective:Cisplatin-based chemotherapy is still considered the first-line therapeutic strategy for many cancers.However,resistant to chemotherapy is a major obstacle for the successful treatment in cancer patients.Therefore,the development of novel therapy against cisplatin-resistance cancer is imperative.Photodynamic therapy(PDT),which is a non-invasive combinatorial therapeutic modality using light, photosensitizer(PS) and oxygen,may provide an unprecedented tool to develop more effective treatments.When PSs in cells are exposed to specific wavelengths of light,reactive oxygen species(ROS) are generated,which cause cellular damage that leads to tumor cell death.Pyropheophorbide-a methylester(MPPa),is a semi-synthetic photosensitizer derived from chlorophyll a,which bears the advantage of having stable property and high quantum yield.To provide experimental basis for its application in cisplatin-resistance cancer,the biological effects of MPPa-photodynamic therapy in cisplatin-resistance cancer cells will be discussed in this article.Materials/Methods:Human cisplatin-resistance lung cancer cells A549/DDP were co-cultured with MPPa(0,1,2,4,8,16 μmol/L) and exposed to light(0,0.6,1.2,2.4,3.6,4.8 J/cm2),cell viability was determined with CCK-8 assay.The MPPa concentration of 2 μmol/L and the light energy of 2.4 J/cm2 were chosen for PDT. Flow cytometry was used to detect apoptosis,DCFH-DA staining was employed to observe reactive oxygen species,and Western blot was used to detect the expressions of Bax and Bcl-2 proteins.Results:The proliferation of A549/DDP cells was suppressed by MPPa-PDT.The apoptotic rate in the MPPa-PDT group was significantly higher than that in control,MPPa or light group(P<0. 05).The level of ROS was increased.The expression of Bax was increased,and that of Bcl-2 was decreased.Conclusion:MPPa-photodynamic therapy can significantly suppress cell vaiability, and induce apoptosis in human cisplatin-resistance cancer cells.