Photodynamic effects of mTHPC on human colon adenocarcinoma cells: photocytotoxicity, subcellular localization and apoptosis.
The photodynamic properties of meta-tetra(hydroxyphenyl)chlorin (mTHPC), a promising second-generation photosensitizer, were investigated using a human colon adenocarcinoma cell line (Colo 201 cells). The study on photocytotoxicity using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction assay showed that mTHPC was an effective photosensitizer on Colo 201 cells. The photocytotoxicity of mTHPC showed both drug and light dose-dependent characteristics. To reach LD50, namely, the dose at which 50% of the cells were killed, only 0.45+/-0.15 microg/mL of mTHPC and 3 J/cm2 of light dose were required. The presence of 10% fetal calf serum in culture medium significantly decreased the incorporation of mTHPC into cells and resulted in the reduction of photodynamic efficacy. Using confocal laser scanning microscopy, mTHPC was first shown to localize in lysosomes rather than in mitochondria. Furthermore, nuclear stainings demonstrated that photodynamic therapy with mTHPC induced apoptosis in Colo 201 cells.
Leung
W N
WN
School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, People's Republic of China. awnleung@hkbu.edu.hk
Sun
X
X
Mak
N K
NK
Yow
C M
CM
D000230:Adenocarcinoma / Q000188:drug therapy*; D017209:Apoptosis / Q000187:drug effects*; D003110:Colonic Neoplasms / Q000188:drug therapy*; D006801:Humans; D008652:Mesoporphyrins / Q000378:metabolism / Q000494:pharmacology*; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000378:metabolism / Q000494:pharmacology*; D013347:Subcellular Fractions / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D008652:Mesoporphyrins; D017319:Photosensitizing Agents; C072269:temoporfin