title: [Effects of hypericin associated with radiotherapy on human laryngeal squamous cell carcinoma strain Hep-2].
abstract: OBJECTIVE
  To study effects of hypericin associated with radiotherapy 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, 1.0, 2.0, 3.0 microg/ml, then 5 Gy radiation were given after an hour. Other groups Hep-2 culture cells were also exposed to different concentration hypericin as 5, 10, 20, 25 microg/ml, and no radiation were given. In all groups, contrast group was set up. And 48 hours later, growth characteristics of Hep-2 were studied by morphological observation, MTT assay and flow cytometry.
  
  
  RESULTS
  In normal contrast group, Hep-2 cells grew intensively and contacted with each other. And cellular swelling was found when Hep-2 cells were only treated with radiotherapy. When Hep-2 cells were treated with both Hypericin and radiotherapy, more cells swelled and cell number declined greatly. In higher dose Hypericin group, necrosis could be found. MTT assay showed the Hep-2 cells growth was significantly inhibited when treated with both hypericin and radiotherapy. Flow cytometry showed hypericin could block cell growth at G0/G1 phase and induced laryngeal cells into apoptosis whether with radiotherapy or not. But Hep-2 cells only treated with hypericin could not get same powerful effect as combination with radiotherapy.
  
  
  CONCLUSIONS
  Human laryngeal squamous cell carcinoma strain Hep-2 can be inhibited and induced into apoptosis by treated with hypericin combination with radiotherapy.
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Jilin University China-Japan Union Hospital, Changchun. syxmy2002@sina.com
authors.forename: Yuxin
authors.initials: Y
authors.lastname: Sun
authors.forename: Hongjun
authors.initials: H
authors.lastname: Xu
authors.forename: Shuai
authors.initials: S
authors.lastname: Tang
authors.forename: Yan
authors.initials: Y
authors.lastname: Meng
authors.forename: Zhen
authors.initials: Z
authors.lastname: Dong
authors.forename: Zhanquan
authors.initials: Z
authors.lastname: Yang
mesh_terms: D000873:Anthracenes; D017209:Apoptosis / Q000187:drug effects* / Q000528:radiation effects*; D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000532:radiotherapy; D045744:Cell Line, Tumor; D006801:Humans; D007822:Laryngeal Neoplasms / Q000473:pathology / Q000532:radiotherapy; D010569:Perylene / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D000873:Anthracenes; D010569:Perylene; C004965:hypericin