title: Betulinic acid: a new cytotoxic compound against malignant head and neck cancer cells.
abstract: BACKGROUND
  A new compound, betulinic acid, has been found to be cytotoxic against a variety of tumor cells originating from the neural crest. Its efficacy against head and neck squamous cellular carcinoma cell lines has so far not been tested.
  
  
  METHODS
  Cell numbers were assayed by automated counting; caspase activation and programmed cell death were determined using an antibody specific for an apoptosis-associated epitope in epithelial cells. The expression pattern of Bcl-2 family members was assessed by Western blotting.
  
  
  RESULTS
  In two HNSCC cell lines betulinic acid induced apoptosis, which was characterized by a dose-dependent reduction in cell numbers, emergence of apoptotic cells, and an increase in caspase activity. Western blot analysis of the expression of various Bcl-2 family members in betulinic acid-treated cells showed, surprisingly, a suppression of the expression of the proapoptotic protein Bax but no changes in Mcl-1 or Bcl-2 expression.
  
  
  CONCLUSIONS
  These data clearly demonstrate for the first time that betulinic acid has apoptotic activity against HNSCC cells.
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria. dietmar.thrunher@univie.ac.at
authors.forename: Dietmar
authors.initials: D
authors.lastname: Thurnher
authors.forename: Dritan
authors.initials: D
authors.lastname: Turhani
authors.forename: Martina
authors.initials: M
authors.lastname: Pelzmann
authors.forename: Bettina
authors.initials: B
authors.lastname: Wannemacher
authors.forename: Birgit
authors.initials: B
authors.lastname: Knerer
authors.forename: Michael
authors.initials: M
authors.lastname: Formanek
authors.forename: Volker
authors.initials: V
authors.lastname: Wacheck
authors.forename: Edgar
authors.initials: E
authors.lastname: Selzer
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology* / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D020169:Caspases / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D006258:Head and Neck Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D006801:Humans; D053978:Pentacyclic Triterpenes; D014315:Triterpenes / Q000494:pharmacology* / Q000627:therapeutic use; D000094062:Betulinic Acid
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D053978:Pentacyclic Triterpenes; D014315:Triterpenes; D020169:Caspases; D000094062:Betulinic Acid