Effects of BAPTA-AM and forskolin on apoptosis and cytochrome c release in photosensitized Chinese hamster V79 cells.
The mechanism of caspase-3-dependent apoptosis induced by photodynamic therapy (PDT) of cultured Chinese hamster V79 cells with pheophorbide a (PPa) was investigated. The PPa-PDT induced rapid apoptosis within 30 min after irradiation of cells. This apoptosis was inhibited by the 1O2 quencher N3- and caspase-3 inhibitor acetyl-Asp-Glu-Val-Asp-aldehyde, suggesting that 1O2 activated caspase-3 and then caused apoptosis. The intracellular calcium [Ca2+]i chelator (acetoxymethyl)-1,2-bis(o-aminophenoxy)ethane N,N,N',N'-tetraacetic acid (BAPTA-AM) and the cyclic adenosine monophosphate (cAMP)-increasing agent forskolin also inhibited not only the PPa-PDT-induced activation of caspase-3 but also apoptosis in V79 cells. Furthermore, PPa-PDT-induced cytochrome c release from mitochondria was found to be inhibited by the treatment with BAPTA-AM but not forskolin. These results indicated that [Ca2+]i and cAMP independently serve as regulators for PPa-PDT-induced apoptosis in the upstream of caspase-3.
Inanami
O
O
Department of Environmental Veterinary Medicine, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan. inanami@vetmed.hokudai.ac.jp
Yoshito
A
A
Takahashi
K
K
Hiraoka
W
W
Kuwabara
M
M
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002460:Cell Line; D002734:Chlorophyll / Q000031:analogs & derivatives / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology*; D006224:Cricetinae; D003574:Cytochrome c Group / Q000378:metabolism; D004533:Egtazic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000494:pharmacology
D003574:Cytochrome c Group; D017319:Photosensitizing Agents; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; D002734:Chlorophyll; D005576:Colforsin; D004533:Egtazic Acid; D053148:Caspase 3; D020169:Caspases; C032623:pheophorbide a