The effect of vitamin A on the migration and DNA synthesis of rat bladder tumor cell line NBT II in culture.
In the presence of vitamin A, NBT II cells, derived from a carcinoma of rat bladder, grew as a monolayer with diminished piling up. Keratinization, which normally appeared within stratified cells in postconfluent cultures, was inhibited. A "wounding" technique suitable for quantitative analysis of cell migration was developed for confluent cultures grown on glass coverslips. Vitamin A treatment enhanced the migration of cells from the wound edge. In dense postconfluent monolayer cultures, vitamin A treatment maintained a higher percentage of cells in DNA synthesis than in the control cultures, as determined by 3H-TdR uptake and autoradiography. In contrast, in sparse cultures vitamin A did not stimulate DNA synthesis or increase the mitotic index. This stimulatory effect, limited to dense cultures, may be attributable to vitamin A causing viable cells to be shed into the medium, thereby maintaining the monolayer just at confluence. Thus vitamin A inhibits squamous cell differentiation, enhances migration, and maintains the culture in the proliferative phase. In a different system of high cell density, NBT II aggregates cultured in a combined matrix of chick plasma clot and collagen-coated sponge, vitamin A also enhanced the migration of cells. These results may explain, in part, the failure of vitamin A to inhibit completely the growth of some established tumors.
D000818:Animals; D001345:Autoradiography; D002449:Cell Aggregation / Q000187:drug effects; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects*; D004273:DNA, Neoplasm / Q000096:biosynthesis*; D004305:Dose-Response Relationship, Drug; D008940:Mitotic Index / Q000187:drug effects; D051381:Rats; D001749:Urinary Bladder Neoplasms / Q000378:metabolism / Q000473:pathology*; D014801:Vitamin A / Q000378:metabolism / Q000494:pharmacology*
D004273:DNA, Neoplasm; D014801:Vitamin A