title: In vitro and in vivo antitumor activity of a novel porphyrin-based photosensitizer for photodynamic therapy.
abstract: OBJECTIVE
  Photodynamic therapy (PDT) is a promising treatment in cancer therapy, based on the use of a photosensitizer activated by visible light in the presence of oxygen. Nowadays significant research efforts have been focused on finding a new photosensitizer. In the present paper, the antitumor effects of a novel porphyrin-based photosensitizer, {Carboxymethyl-[2-(carboxymethyl-{[4-(10,15,20-triphenylporphyrin-5-yl)-phenylcarbamoyl]-methyl}-amino)-ethyl]-amino}-acetic acid (ATPP-EDTA) on two types of human malignant tumor cells in vitro and a gastric cancer model in nude mice, were evaluated.
  
  
  METHODS
  The PDT efficacy with ATPP-EDTA in vitro was assessed by MTT assay. The intracellular accumulation was detected with fluorescence spectrometer, and the intracellular distribution was determined by laser scanning confocal microscopy. The mode of cell death was investigated by Hoechst 33342 staining and flow cytometer. BGC823-derived xenograft tumor model was established to explore the in vivo antitumor effects of ATPP-EDTA.
  
  
  RESULTS
  ATPP-EDTA exhibited intense phototoxicity on both cell lines in vitro in concentration- and light dose-dependent manners meanwhile imposing minimal dark cytotoxicity. The accumulation of ATPP-EDTA in two malignant cell lines was time-dependent and prior compared to normal cells. It was mainly localized at lysosomes, but induced cell death by apoptotic pathway. ATPP-EDTA significantly inhibited the growth of BGC823 tumors in nude mice (160 mW/cm(2), 100 J/cm(2)).
  
  
  CONCLUSIONS
  Present studies suggest that ATPP-EDTA is an effective photosensitizer for PDT to tumors. It distributed in lysosomes and caused cell apoptosis. ATPP-EDTA, as a novel photosensitizer, has a great potential for human gastric cancer treatment in PDT and deserves further investigations.
authors.affiliation: Central Laboratory of Heping Hospital, Changzhi Medical College, Changzhi City, 046000, Shanxi Province, People's Republic of China.
authors.forename: Jing-Jing
authors.initials: JJ
authors.lastname: Chen
authors.forename: Ge
authors.initials: G
authors.lastname: Hong
authors.forename: Li-Jing
authors.initials: LJ
authors.lastname: Gao
authors.forename: Tian-Jun
authors.initials: TJ
authors.lastname: Liu
authors.forename: Wen-Jun
authors.initials: WJ
authors.lastname: Cao
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D004492:Edetic Acid / Q000031:analogs & derivatives / Q000493:pharmacokinetics / Q000494:pharmacology; D005260:Female; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000493:pharmacokinetics / Q000494:pharmacology*; D011166:Porphyrins / Q000493:pharmacokinetics / Q000494:pharmacology*; D011897:Random Allocation; D013050:Spectrometry, Fluorescence; D013274:Stomach Neoplasms / Q000188:drug therapy / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
chemical_list: D017319:Photosensitizing Agents; D011166:Porphyrins; D004492:Edetic Acid