title: [Effects of hypericin associated with light irradiation on human laryngeal squamous cell carcinoma strain Hep-2].
abstract: OBJECTIVE
  To study effects of hypericin associated with light irradiation on human laryngeal squamous cell carcinoma strain Hep-2.
  
  
  METHODS
  Using techniques of tumor cells culture in vitro, Hep-2 cells were exposed to different concentration hypericin as 0.5, 1.0, 2.0, 3.0, 5.0 microg/ml, then 10 minutes 7.5 J/cm2 light irradiation was given after an hour. Other groups Hep-2 culture cells were also exposed to different concentration hypericin as 5.0, 10.0, 20.0, 25.0 microg/ml, without light irradiation. In all groups, contrast groups were set up. And 48 hours later, growth characteristics of Hep-2 cells were studied by morphological observation, fluorescence microscope, MTT assay and flow cytometry.
  
  
  RESULTS
  In normal contrast group, Hep-2 cells grew intensively and contacted with each other. However, cells which were treated with hypericin, combination with light irradiation were declined greatly. In higher dose hypericin group, necrosis could be found. MTT assay showed that hypericin associated with light irradiation inhibited growth of laryngeal cell with dose dependence manner. Flow cytometry showed that hypericin with light irradiation could block cell growth at G0/G1 phase, inducing apoptosis of laryngeal cell. Under fluorescence microscope, some sings of cell apoptosis including coagulation of chromatin, fragmentation of nuclei and apoptotic body could be found.
  
  
  CONCLUSIONS
  Human laryngeal squamous cell carcinoma strain Hep-2 can be inhibited and induced into apoptosis by treated with hypericin combination with light irradiation.
authors.affiliation: Department of Otorhinolaryngology Head and Neck Surgery, Jilin University China-Japan Union Hospital, Changchun 130031, China.
authors.forename: Yu-Xin
authors.initials: YX
authors.lastname: Sun
authors.forename: Yan
authors.initials: Y
authors.lastname: Meng
authors.forename: Zhen
authors.initials: Z
authors.lastname: Dong
authors.forename: Zhan-Quan
authors.initials: ZQ
authors.lastname: Yang
mesh_terms: D000873:Anthracenes; D017209:Apoptosis / Q000187:drug effects* / Q000528:radiation effects*; D002294:Carcinoma, Squamous Cell / Q000473:pathology; D049109:Cell Proliferation / Q000187:drug effects* / Q000528:radiation effects*; D056945:Hep G2 Cells; D006801:Humans; D007822:Laryngeal Neoplasms / Q000473:pathology; D008027:Light; D010569:Perylene / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D000873:Anthracenes; D010569:Perylene; C004965:hypericin