title: Hematoporphyrin monomethyl ether-mediated photodynamic therapy selectively kills sarcomas by inducing apoptosis.
abstract: We investigated the antitumor effect and mechanism of hematoporphyrin monomethyl ether-mediated photodynamic therapy (HMME-PDT) in sarcomas. Intracellular uptake of HMME by osteosarcoma cells (LM8 and K7) was time- and dose-dependent, while this was not observed for myoblast cells (C2C12) and fibroblast cells (NIH/3T3). HMME-PDT markedly inhibited the proliferation of sarcoma cell lines (LM8, MG63, Saos-2, SW1353, TC71, and RD) (P<0.05), and the killing effect was improved with increased HMME concentration and energy intensity. Flow cytometry analysis revealed that LM8, MG63, and Saos-2 cells underwent apoptosis after treatment with HMME-PDT. Additionally, apoptosis was induced after HMME-PDT in a three-dimensional culture of osteosarcoma cells. Hoechst 33342 staining confirmed apoptosis. Cell death caused by PDT was rescued by an irreversible inhibitor (Z-VAD-FMK) of caspase. However, cell viability was not markedly decreased compared with the HMME-PDT group. Expression levels of caspase-1, caspase-3, caspase-6, caspase-9, and poly (ADP-ribose) polymerase (PARP) proteins were markedly up-regulated in the treatment groups and increased with HMME concentration as determined by western blot analysis. In vivo, tumor volume markedly decreased at 7-16 days post-PDT. Hematoxylin and eosin staining revealed widespread necrotic and infiltrative inflammatory cells in the HMME-PDT group. Immunohistochemistry analysis also showed that caspase-1, caspase-3, caspase-6, caspase-9, and PARP proteins were significantly increased in the HMME-PDT group. These results indicate that HMME-PDT has a potent killing effect on osteosarcoma cells in vitro and significantly inhibits tumor growth in vivo, which is associated with the caspase-dependent pathway.
authors.affiliation: Department of Orthopedics, Shanghai First People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zeng
authors.forename: Mengxiong
authors.initials: M
authors.lastname: Sun
authors.forename: Chenghao
authors.initials: C
authors.lastname: Zhou
authors.forename: Fei
authors.initials: F
authors.lastname: Yin
authors.forename: Zhuoying
authors.initials: Z
authors.lastname: Wang
authors.forename: Yingqi
authors.initials: Y
authors.lastname: Hua
authors.forename: Zhengdong
authors.initials: Z
authors.lastname: Cai
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001859:Bone Neoplasms / Q000188:drug therapy / Q000378:metabolism; D020169:Caspases / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D006415:Hematoporphyrins / Q000494:pharmacology*; D006801:Humans; D051379:Mice; D041681:NIH 3T3 Cells; D012516:Osteosarcoma / Q000188:drug therapy* / Q000378:metabolism; D010778:Photochemotherapy / Q000379:methods; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism
chemical_list: D006415:Hematoporphyrins; C494379:hematoporphyrin monomethyl ether; D011065:Poly(ADP-ribose) Polymerases; D020169:Caspases