Inhibition of chemically-induced neoplastic transformation by a novel tetrasodium diphosphate astaxanthin derivative.
Carotenoids have been implicated in numerous epidemiological studies as being protective against cancer at many sites, and their chemopreventive properties have been confirmed in laboratory studies. Astaxanthin (AST), primarily a carotenoid of marine origin, responsible for the pink coloration of salmon, shrimp and lobster, has received relatively little attention. As with other carotenoids, its highly lipophilic properties complicate delivery to model systems. To overcome this issue we have synthesized a novel tetrasodium diphosphate astaxanthin (pAST) derivative with aqueous dispersibility of 25.21 mg/ml. pAST was delivered to C3H/10T1/2 cells in an aqueous/ethanol solution and compared with non-esterified AST dissolved in tetrahydrofuran. We show pAST to (i) upregulate connexin 43 (Cx43) protein expression; (ii) increase the formation of Cx43 immunoreactive plaques; (iii) upregulate gap junctional intercellular communication (GJIC); and (iv) cause 100% inhibition of methylcholanthrene-induced neoplastic transformation at 10(-6) M. In all these assays, pAST was superior to non-esterified AST itself; in fact, pAST exceeded the potency of all other previously tested carotenoids in this model system. Cleavage of pAST to non-esterified (free) AST and uptake into cells was also verified by HPLC; however, levels of free AST were approximately 100-fold lower than in cells treated with AST itself, suggesting that pAST possesses intrinsic activity. The dual properties of water dispersibility (enabling parenteral administration in vivo) and increased potency should prove extremely useful in the future development of cancer chemopreventive agents.
Hix
Laura M
LM
Department of Cell and Molecular Biology, University of Hawaii at Manoa, Honolulu, HI 96822, USA.
Frey
Dean A
DA
McLaws
Mark D
MD
Østerlie
Marianne
M
Lockwood
Samuel F
SF
Bertram
John S
JS
D000818:Animals; D016588:Anticarcinogenic Agents / Q000493:pharmacokinetics / Q000494:pharmacology*; D000970:Antineoplastic Agents / Q000494:pharmacology; D001565:Benzoates / Q000494:pharmacology; D002338:Carotenoids / Q000494:pharmacology; D002460:Cell Line; D002471:Cell Transformation, Neoplastic / Q000187:drug effects*; D005347:Fibroblasts / Q000187:drug effects; D017629:Gap Junctions / Q000187:drug effects / Q000502:physiology; D051379:Mice; D008809:Mice, Inbred C3H; D012176:Retinoids / Q000494:pharmacology; D024341:Xanthophylls; D019207:beta Carotene / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000494:pharmacology
D016588:Anticarcinogenic Agents; D000970:Antineoplastic Agents; D001565:Benzoates; D012176:Retinoids; D024341:Xanthophylls; C505056:astaxanthin diphosphate; D019207:beta Carotene; D002338:Carotenoids; C038864:4-(2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)-1-propenyl)benzoic acid; C005948:astaxanthine