title: Apoptosis and expression of cytokines triggered by pyropheophorbide-a methyl ester-mediated photodynamic therapy in nasopharyngeal carcinoma cells.
abstract: The photodynamic properties of pyropheophorbide-a methyl ester (MPPa), a semi-synthetic photosensitizer derived from chlorophyll a, were evaluated in a human nasopharyngeal carcinoma HONE-1 cell line. MPPa was non-toxic to the HONE-1. At the concentrations of 0.5-2μM, MPPa-mediated a drug dose-dependent photocytotoxicity in the HONE-1 cells. Confocal microscopy revealed a subcellular localization of MPPa in mitochondria and the Golgi apparatus. MPPa PDT-induced apoptosis was associated with the collapse of mitochondrial membrane potential, release of cytochrome c, the up-regulation of endoplasmic reticulum (ER) stress proteins (calnexin, Grp 94 and Grp78), and the activation of caspases-3 and -9. The photocytotoxicity was reduced by the corresponding specific caspase inhibitors. MPPa PDT-treated HONE-1 cells also up-regulated the gene expression of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) and beta-chemokines (MIP-1β, MPIF-1, and MPIF-2). These results suggest that the MPPa may be developed as a chlorophyll-based photosensitizer for the treatment of nasopharyngeal carcinoma.
authors.affiliation: Department of Biology, Hong Kong Baptist University, 224 Waterloo Road, Hong Kong, China.
authors.forename: K M
authors.initials: KM
authors.lastname: Li
authors.affiliation: Department of Biology, Hong Kong Baptist University, 224 Waterloo Road, Hong Kong, China.
authors.forename: X
authors.initials: X
authors.lastname: Sun
authors.affiliation: Department of Biology, Hong Kong Baptist University, 224 Waterloo Road, Hong Kong, China.
authors.forename: H K
authors.initials: HK
authors.lastname: Koon
authors.affiliation: School of Chinese Medicines, Hong Kong Baptist University, China.
authors.forename: W N
authors.initials: WN
authors.lastname: Leung
authors.affiliation: Department of Biology, Chinese University of Hong Kong, China.
authors.forename: M C
authors.initials: MC
authors.lastname: Fung
authors.affiliation: Department of Biology, Hong Kong Baptist University, 224 Waterloo Road, Hong Kong, China.
authors.forename: R N S
authors.initials: RN
authors.lastname: Wong
authors.affiliation: Department of Biology, Hong Kong University of Science and Technology, Hong Kong, China.
authors.forename: Maria L
authors.initials: ML
authors.lastname: Lung
authors.affiliation: Department of Chemistry, Hong Kong University of Science and Technology, Hong Kong, China.
authors.forename: C K
authors.initials: CK
authors.lastname: Chang
authors.affiliation: Department of Biology, Hong Kong Baptist University, 224 Waterloo Road, Hong Kong, China.
authors.forename: N K
authors.initials: NK
authors.lastname: Mak