title: Effects of amitriptyline and fluoxetine upon the in vitro proliferation of tumor cell lines.
abstract: Previous publications have suggested that commonly prescribed antidepressants have the potential to stimulate the proliferation of extant tumors in human and rodent in vivo and in vitro models. The direct effects of amitriptyline and fluoxetine were evaluated in assays that detect different aspects of proliferative responses at pharmacologically relevant drug concentrations. Three in vitro assays of cellular proliferation and clonal growth were used with human (MCF7, PA-1 and LS174T) and murine (B16.f10, C-3 and B16.f1) tumor cell lines. The cells were exposed to amitriptyline or fluoxetine (0.001-100 microM) for different time periods (1-7 days) and at varying serum concentrations (0.1-15%). Amitriptyline and fluoxetine failed to significantly stimulate tumor cell proliferation, DNA synthesis, or colony formation. Both drugs inhibited B16.f10 colony growth at concentrations above 5 microM along with significant suppression of DNA synthesis in B16.f10 and C-3 cells at 30 microM. Although there were generally no effects on cell proliferation by the drugs in the microtiter tetrazolium assay, several rare instances of stimulation were noted. Amitriptyline and fluoxetine were consistent in their lack of effect or inhibition with the human or murine tumor cell lines in conventional in vitro assays of cell proliferation and clonogenicity in optimal or suboptimal culture conditions.
authors.affiliation: Office of Testing and Research, Center for Drug Evaluation and Research, Food and Drug Administration, NLRC-2400B, 5600 Fishers Lane, Rockville, MD 20857, USA. volpe@cder.fda.gov
authors.forename: Donna A
authors.initials: DA
authors.lastname: Volpe
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Ellison
authors.forename: Ralph E
authors.initials: RE
authors.lastname: Parchment
authors.forename: Charles K
authors.initials: CK
authors.lastname: Grieshaber
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Faustino
mesh_terms: D000639:Amitriptyline / Q000494:pharmacology*; D000818:Animals; D018687:Antidepressive Agents, Second-Generation / Q000494:pharmacology*; D000929:Antidepressive Agents, Tricyclic / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects*; D045744:Cell Line, Tumor; D003114:Colony-Forming Units Assay; D004273:DNA, Neoplasm / Q000096:biosynthesis; D005260:Female; D005473:Fluoxetine / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D009369:Neoplasms / Q000378:metabolism / Q000473:pathology*; D013778:Tetrazolium Salts; D013844:Thiazoles; D013936:Thymidine / Q000378:metabolism
chemical_list: D018687:Antidepressive Agents, Second-Generation; D000929:Antidepressive Agents, Tricyclic; D004273:DNA, Neoplasm; D013778:Tetrazolium Salts; D013844:Thiazoles; D005473:Fluoxetine; D000639:Amitriptyline; C022616:thiazolyl blue; D013936:Thymidine