title: Involvement of mitochondria-caspase pathway in Hemoporfin-mediated cell death.
abstract: Hemoporfin is a novel second-generation porphyrin-related photosensitizer for ovarian cancer photodynamic treatment (PDT). The purpose of this study was to investigate the molecular mechanisms of Hemoporfin-mediated photocytotoxicity. Human epithelial ovarian cancer cell line 3AO was incubated with different concentrations of Hemoporfin, and phototoxic effects of Hemoporfin on cells were determined using a Cell Viability Analyzer. Apoptosis or necrosis was determined by flow cytometry analysis using the Annexin V-FITC apoptosis kit. Cellular caspase activation was determined using the fluorescent assay kit for caspase-3 and caspase-9. Rhodamine123 was used as a mitochondrial probe and Lucifer Yellow as a lysosomal probe to investigate the intracellular localization of Hemoporfin in 3AO cancer cells. We demonstrated that both high-dose (30 microg mL(-1)) and low-dose (3 microg mL(-1)) Hemoporfin significantly reduced the viability of ovarian cancer cell 3AO with light illumination, and the photocytotoxicity was dose-dependent (P < 0.01). Using a mitochondrial fluorescence probe, we demonstrated a distinct mitochondrial aggregation in 3AO cells with a low concentration of Hemoporfin. Loss of mitochondrial membrane potential was detected as early as 1 h after Hemoporfin-mediated PDT. PDT with low-dose Hemoporfin predominantly induced apoptosis but not necrosis, and both caspase-3 and caspase-9 were activated. Based on our results, mitochondria play an important role in the Hemoporfin-induced apoptosis, and mitochondria membrane potential loss initiated apoptosis via the activation of caspases. Understanding the mechanisms involved in PDT-mediated apoptosis may improve its therapeutic efficacy and facilitate its transition into the clinic.
authors.affiliation: Department of Obstetrics and Gynecology, Qilu Hospital, Shandong University, Shandong, China.
authors.forename: Yongqing
authors.initials: Y
authors.lastname: Wei
authors.forename: Beihua
authors.initials: B
authors.lastname: Kong
authors.forename: Kun
authors.initials: K
authors.lastname: Song
authors.forename: Xun
authors.initials: X
authors.lastname: Qu
authors.forename: Qiong
authors.initials: Q
authors.lastname: Jin
authors.forename: Qifeng
authors.initials: Q
authors.lastname: Yang
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism*; D053453:Caspase 9 / Q000378:metabolism*; D045744:Cell Line, Tumor; D048430:Cell Shape / Q000187:drug effects; D006415:Hematoporphyrins / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D008928:Mitochondria / Q000187:drug effects* / Q000201:enzymology*; D015398:Signal Transduction / Q000187:drug effects*
chemical_list: D006415:Hematoporphyrins; C494379:hematoporphyrin monomethyl ether; D053148:Caspase 3; D053453:Caspase 9