The Effects Of Photoinactivation Of LED-Activated MPPa On Cisplatin-Resistant Human Ovarian Carcinoma Cell

Background:Ovarian carcinoma is the primary cause of high mortality from gynecological malignancies.While chemotherapy is an alternative treatment,but chemoresistance severely limits its effects.It is possible for doctors to explore novel therapeutic strategies to improve the clinical outcomes.Increasing evidences show that photodynamic therapy is a potential therapeutic modality for ovarian cancer and some other gynecological diseases.But photoinactivation of chemoresistance of cancer is not clearly.The study aims to investigate the photodynamic effects of a new light delivery device based on lighting emitting diode (LED)technology on a cisplatin-resistant human ovarian carcinoma cell line COC1/DDP cells.Material/Methods:The intracellular fluorescence of MPPa in the COC1/DDP cells was measured by flow cytometry(FCM).The photocytotoxicity and mode of death induced by a novel developed photosensitizer MPPa were investigated in a cisplatin-resistant human ovarian carcinoma cell line COC1/DDP,in which the drug concentration range was 0.25-4μM and LED arrays energy density range 0.125-8 J/cm~2. Photodynamic toxicity was investigated 24 h after treatment,cell morphology was also observed by light microscopy at the same time. Furthermore,the temperature changes of solution were recorded as well. Apoptosis was determined using FCM with propidum iodine staining,and nuclear staining with Hoechst33258.Fine structure was also observed by transmission electron microscopy.Subcellular localization patterns of MPPa were determined by confocal laser scanning microscopy and organelle-specific fluorescent probes.Finally,mitochondrial membrane potential was evaluated by Rhodamine 123 assay.Results:The intracellular fluorescence of MPPa in the COC1/DDP cells peaked at round 18 h after sensitization and the highest absorption peak of MPPa occurs in this region.Therefore,the cells were sensitized with MPPa for 20 h in the study of photocytotoxicity.No significant dark cytotoxicity of MPPa was observed at the dose range of 0.25-4μM,so did LED arrays alone in the COC1/DDP cells at the dose range of 0.125-8 J/cm~2,but a little proliferation was displayed.LED-activated MPPa mediates a dose-and light-dependent photocytotoxicity in the COC1/DDP cells.And it was also confirmed that apparent heteromorphosis of COC1/DDP cells,which were sensitized and irradiated by LED arrays, can be seen through inverted microscope 24 h after photodynamic treatment.No significant temperature changes were revealed.Nuclear staining revealed that DNA condensation and fragmentation occurred post-photodynamic therapy,indicating the cell death was in the apoptotic mode.Apoptotic rate 6h after PDT with MPPa(2μM)increased to 16.71%under the LED energy of 1 J/cm~2.Transmission electron microscopy clarified the fine structure of COC1/DDP cells 6 h after photodynamic treatment,that apoptotic bodies and necrosis was displayed. Organelle staining revealed that MPPa was found to localize thickly in the intracellular membrane system,namely the endoplasmic reticulum,Golgi apparatus and mitochondria,but partly in lysosomes,in the COC1/DDP cells.Moreover,mitochondrial membrane potential was collapsed 6 h after being sensitized with 2μM MPPa 20 h and exposed to LED with 1 J/cm~2.Conclusion:Photoinactivation of cisplatin-resistant human ovarian carcinoma cell line COC1/DDP by LED-activated MPPa could be significantly effective and photodynamic therapy is a potential therapeutic modality for the treatment of chemoresistant cancer.LED will become an alternative light source for photodynamic therapy.