Cancer prevention by carotenoids. Mechanistic studies in cultured cells.
In 10T1/2 cells several dietary carotenoids have been shown to be capable of inhibiting carcinogen-induced neoplastic transformation. Their action appears qualitatively similar to the previously documented action of retinoids in this cell system; however, higher concentrations (10-1000-fold) are required. Both types of compound were found to strongly upregulate gap junctional intercellular communication, and these activities were statistically correlated. Upregulation of gap junctional intercellular communication was caused by the increased expression of connexin 43, a structural protein of the gap junction. Increased junctional communication has been proposed to be mechanistically linked to inhibition of transformation in 10T1/2 cells. In this model the gap junction serves as a conduit for growth regulatory signals from normal to initiated cells. These putative signals act to suppress transformation of the carcinogen-initiated cell.
Bertram
J S
JS
Cancer Research Center of Hawaii, University of Hawaii, Honolulu 96813.
D000818:Animals; D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D016644:Canthaxanthin / Q000494:pharmacology*; D002338:Carotenoids / Q000494:pharmacology*; D002450:Cell Communication / Q000187:drug effects; D002460:Cell Line; D002471:Cell Transformation, Neoplastic / Q000187:drug effects*; D002478:Cells, Cultured; D018031:Connexin 43 / Q000096:biosynthesis*; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D007365:Intercellular Junctions / Q000187:drug effects; D015227:Lipid Peroxidation / Q000187:drug effects; D008748:Methylcholanthrene / Q000633:toxicity*; D051379:Mice; D008809:Mice, Inbred C3H; D012867:Skin / Q000166:cytology / Q000187:drug effects; D012879:Skin Physiological Phenomena
D016588:Anticarcinogenic Agents; D018031:Connexin 43; D002338:Carotenoids; D016644:Canthaxanthin; D008748:Methylcholanthrene