title: [Main factors affecting the effect of photodynamic therapy against human esophageal cancer cells in vitro].
abstract: OBJECTIVE
  To evaluate the tumor cell-killing effect of photodynamic therapy against human esophageal cancer cells in vitro and identify the main factors affecting the effect.
  
  
  METHODS
  Human esophageal cancer Eca-109 cells were incubated for 24 h in vitro with hematoporphyrin derivative (HpD) and Photofrin at different concentrations prior to exposure to a light energy density of 15 J/cm(2) delivered from a DIOMED 630 PDT system. The cell killing effect was also evaluated for different HpD concentrations combined with 3 light energy densities (10, 30, and 50 J/cm(2)), respectively. The cell survival rate was measured using MTT assay, and fluorescence spectrometry was used to detect the intracellular photosensitizer fluorescence of the tumor cells after incubation with HpD for 4 h.
  
  
  RESULTS
  The cell survival rate after incubation with the two photosensitizers at different concentrations were significantly different, and under the 3 different light energy densities, incubation of the cells with different HpD concentrations also resulted in significantly different cell survival rates (P<0.05). At the 4 low photosensitizer concentrations and with different light energy densities, the cell survival rates were similar (P>0.05), but the 4 higher photosensitizer concentrations resulted in significant difference in the cells survival (P<0.05). Correlation analysis showed that the intracellular photosensitizer concentration was positively correlated to the photosensitizer concentrations in cell incubation (r=0.997).
  
  
  CONCLUSIONS
  When the light source remains constant, the light energy density, the kinds of photosensitizers and their concentrations are the main factors affecting the Eca-109 cell-killing effect of PDT.
authors.affiliation: Center of Oncology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China. cxh0663@yahoo.com.cn
authors.forename: Xiao-hua
authors.initials: XH
authors.lastname: Chen
authors.forename: Rong-cheng
authors.initials: RC
authors.lastname: Luo
authors.forename: Li-bo
authors.initials: LB
authors.lastname: Li
authors.forename: Xue-mei
authors.initials: XM
authors.lastname: Ding
authors.forename: Cheng-wei
authors.initials: CW
authors.lastname: Lü
authors.forename: Xiao-ping
authors.initials: XP
authors.lastname: Zhou
authors.forename: Xiao
authors.initials: X
authors.lastname: Yan
mesh_terms: D045744:Cell Line, Tumor; D002470:Cell Survival; D017323:Dihematoporphyrin Ether / Q000494:pharmacology; D004938:Esophageal Neoplasms / Q000188:drug therapy*; D017324:Hematoporphyrin Derivative / Q000494:pharmacology; D006414:Hematoporphyrin Photoradiation; D006801:Humans; D008027:Light; D017319:Photosensitizing Agents / Q000494:pharmacology*
chemical_list: D017319:Photosensitizing Agents; D017324:Hematoporphyrin Derivative; D017323:Dihematoporphyrin Ether