title: Inhibitory effects of canthaxanthin on in vitro growth of murine tumor cells.
abstract: The antitumorigenic effects of carotenoids, in addition to their immuno-enhancing effects, may occur by their direct action on growing tumor cells. To test this hypothesis the direct inhibitory effect of various concentrations of canthaxanthin (CX; 4,4'-diketo-beta-carotene), a non-provitamin A carotenoid, was tested on the in vitro growth of JB/MS, B16F10 melanomas and PYB6 fibrosarcoma and murine non-transformed NIH-3T3 (ATCC CRL 1658) cells. At concentrations of 1 x 10(-8) M up to 1 x 10(-4) M, CX significantly reduced the overall number of tumor cells. The greatest inhibition was observed at a CX concentration of 1 x 10(-4) M after 72 h and 96 h of incubation. However, CX had no inhibitory effect on the growth of the non-transformed NIH-3T3 cell line; rather it significantly enhanced growth of this cell line (P less than 0.05) after 96 h of incubation. Thus, the inhibitory action of CX on growing tumor cells appears to be due to its direct actions on tumor cells and not via its conversion to vitamin A or its immuno-enhancing effects.
authors.affiliation: Department of Microbiology and Immunology, University of Arizona, College of Medicine, Tucson 85724.
authors.forename: D S
authors.initials: DS
authors.lastname: Huang
authors.forename: O E
authors.initials: OE
authors.lastname: Odeleye
authors.forename: R R
authors.initials: RR
authors.lastname: Watson
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene; D000704:Analysis of Variance; D000818:Animals; D016644:Canthaxanthin / Q000494:pharmacology* / Q000627:therapeutic use; D002455:Cell Division / Q000187:drug effects*; D002461:Cell Line, Transformed; D002478:Cells, Cultured; D005354:Fibrosarcoma / Q000139:chemically induced / Q000188:drug therapy / Q000473:pathology*; D008546:Melanoma, Experimental / Q000139:chemically induced / Q000188:drug therapy / Q000473:pathology*; D051379:Mice; D012513:Sarcoma, Experimental / Q000139:chemically induced / Q000188:drug therapy / Q000473:pathology*; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D016644:Canthaxanthin; D015127:9,10-Dimethyl-1,2-benzanthracene