INTRODUCTION: Photodynamic therapy (PDT) is a therapeutic modality for the treatment of neoplastic and non-neoplastic diseases. Mitochondria have attracted great attention due to their direct involvement in the cell death process. By inhibiting the mitochondrial activity, it is possible to study other organelles involved in the cell death process. The objective of this study was to evaluate the involvement of mitochondria in induced cell death process in M3 cell line after photosensitization with Photosan3®. METHODS: The experiments involved the following groups: control group I, cells with no treatment; group II PDT, cells incubated with Photosan3®; group III PDT, cells incubated with CsA and Photosan3®; group IV, cells treated only with treated only Staurosporine (STS). After incubation with the photosensitizer, the groups II and III were irradiated using a semiconductor laser diode (λ 670 nm). All groups were incubated at 37 ºC in an atmosphere of 5% CO2 for 24 and 48 h. After this period, all groups were subjected to the MTT (3 - [4,5-dimethyl-thiazol-2-yl] -2,5-diphenyltetrazolium bromide) cytotoxicity assay and labeled with Annexin V and Iodide Propidium to determine the rate of cell death. The analyses were performed by fluorescence microscopy. RESULTS: The results show that PDT Photosan leads to apoptosis of breast cell line M3 by a route independent of the mitochondria. CONCLUSION: The association of CsA and Photosan3® in photodynamic therapy showed the occurrence of cell death (apoptosis) independent of mitochondrial participation.
Mitochondria; Cyclosporine A; Photosan3®; Breast cancer
