Single cell analysis demonstrates a rapid activation of bax in mitochondrion mediated-PDT apoptosis

摘要

Apoptosis is a very important cellular event that plays a key role in pathogeny and therapy of many diseases. One of the important modes cell death by photodynamic therapy (PDT) is apoptosis. The translocation of Bax from the cytosol into the mitochondrial outer membrane is a central event during apoptosis. In this study, we detected the kinetics of Bax activation in the cells with different photosensitizers treatments. Using laser scanning confocal microscopy, we found that Photofrin were localized primarily in mitochondria and N-aspartyl chlorine e6 (NPe6) preferentially localized to lysosomes. The results showed Bax can be activated and translocated from the cytosol to mitochondria by Photofrin-PDT treatment but not by NPe6-PDT treatment in ASTC-a-1 cells. The activation of Bax started 15 minutes after Photofrin-PDT treatment and the process of activation completed within 45 minutes. These results indicated that the initiation and process of Bax activation are different corresponding to different sublocalization photosensitizers treatments. Our data suggests that different sublocalization photosensitizers in PDT treatments photodamaged different organelles and will trigger various apoptotic pathways in PDT treatment.