title: DNA fragmentation induced by cigarette smoke in oral cancer cells.
abstract: OBJECTIVE
  Cigarette smoke (CS) is the main inducer of oral cancer, increasing the prevalence by 4-7 times. We examined induction of apoptosis by CS exposure of SCC-25 and SCC-15 oral cancer cells.
  
  
  METHODS
  After controlled exposure to CS of various durations and at different time points we measured DNA fragmentation to assay apoptotic levels.
  
  
  RESULTS
  SCC-15 cells showed a 70% (p<0.05) increase in apoptotic levels immediately after 30 min of exposure to CS. Twenty-four hours after 30-min CS exposure a further increase in apoptotic levels to 178% (p<0.05) could be observed. However, SCC-15 cells showed a decrease in apoptotic levels immediately after 180-min exposure to CS. CS-exposed SCC-25 cells did not show such CS-related effects.
  
  
  CONCLUSIONS
  SCC-15 and SCC-25 oral cancer cells respond differently to CS regarding apoptotic cell death levels. In this respect, SCC-15 cells are sensitive to CS, while SCC-25 cells are not. Further comparisons between these cells may give insight regarding relationships between CS, apoptosis and invasiveness of oral cancer.
authors.affiliation: Department of Molecular Pharmacology, Medical Faculty, Technion - Israel Institute of Technology, Haifa, Israel.
authors.forename: Rafael M
authors.initials: RM
authors.lastname: Nagler
authors.affiliation: Department of Molecular Pharmacology, Medical Faculty, Technion - Israel Institute of Technology, Haifa, Israel.
authors.forename: Ella
authors.initials: E
authors.lastname: Krayzler
authors.affiliation: Department of Molecular Pharmacology, Medical Faculty, Technion - Israel Institute of Technology, Haifa, Israel.
authors.forename: Leo
authors.initials: L
authors.lastname: Veenman
authors.affiliation: Department of Molecular Pharmacology, Medical Faculty, Technion - Israel Institute of Technology, Haifa, Israel.
authors.forename: Moshe
authors.initials: M
authors.lastname: Gavish
mesh_terms: D017209:Apoptosis; D045744:Cell Line, Tumor; D053938:DNA Fragmentation; D006801:Humans; D009062:Mouth Neoplasms / Q000473:pathology*; D018307:Neoplasms, Squamous Cell / Q000473:pathology*; D012907:Smoking / Q000009:adverse effects*
keywords: Oral cancer; apoptosis; cigarette smoke