[Effect of new photosensitizer CDHS801-mediated photodynamic therapy on bladder cancer: an experimental study]

To investigate the effects of dynamic photodynamic therapy (PDT) on bladder cancer.

Human bladder cancer cells of the line T24 were co-cultured with CDHS801, a photosensitizer, and MitoTracker RED CMXRose and MitoTracker GREEN FM, mitochondria specific fluorescence probe dyes. Laser scanning confocal fluorescence microimaging system was applied to collect the fluorescence of the photosensitizer and the probes. T24 cells were cultured and divided into 4 groups: Group 1 as blank control group, Group 2 undergoing laser irradiation, Group 3, added with CDHS801 for 6h, and Group 4 (PDT group), added with CDHS801 and undergoing laser irradiation. The survival of the cells was examined by MTT colorimetric assay. The morphological changes and apoptosis of the photo-activated T24 cells were investigated by transmission electron microscopy, confocal laser scan microscopy, and flow cytometry.

The fluorescence of the photosensitizer and that of the probes were detected in the cytoplasm and in the peri-nuclear region, mainly in the mitochondria, of the T24 cells. 2. The inhibitory rates of PDT on T24 cells were 0%, 7.3%, 10.8%, and 71.4% in the control group, Group 1, Group 2, and Group 3 respectively. T24 cell photo-activated with CDHS801 showed cell size shrinkage, condensed chromatin and formation of apoptotic body. Flow cytometry showed that apoptosis was seen in 55.31% of the photo-activated cells and peaked in the sub-G1 phase. However, no such changes were seen in the control group.

CDHS801-based PDT can kill bladder cancer T24 cells. CDHS801 is localized in the cytoplasm and peri-nuclear region, mainly mitochondria, of tumor cell. CDHS801 based PDT maybe eliminate the T24 cell by the induction of apoptosis.