title: Tumor promoters stimulate hyperplasia of microtubule organizing center and inhibit DNA synthesis in cultured cells.
abstract: Chemical tumor promoters induce significant morphologic changes in several cultured cell models. In this article we describe a new effect of two potent, chemically different tumor promoters, 12-O-tetradecanoylphorbol-13-acetate (TPA) and dihydroteleocidin B (DHTB) on cultured human HeLa and melanoma cells. Using immunofluorescence microscopy, we observed that TPA and DHTB induced a dramatic increase in the size (greater than or equal to 3X normal diameter) of the centrosome, a microtubule-organizing center, within 24 h of incubation. In HeLa cells the effect was serum- and dose-dependent, was observed in 76-92% of cells within 72 h of incubation, and was associated with an increase in cytoplasm-nucleus ratio and proliferation of microtubules from the centrosome. The tumor promoters inhibited serum-induced DNA synthesis in both cell lines. Electron microscopy revealed the presence of clumps of microcentriole bodies or fragments adjacent to the intact centriole.
mesh_terms: D004247:DNA / Q000096:biosynthesis*; D006131:Growth Inhibitors / Q000494:pharmacology*; D006367:HeLa Cells / Q000187:drug effects / Q000473:pathology; D006801:Humans; D006965:Hyperplasia / Q000139:chemically induced; D007700:Kinetics; D008235:Lyngbya Toxins / Q000494:pharmacology*; D008545:Melanoma / Q000378:metabolism / Q000473:pathology; D008870:Microtubules / Q000187:drug effects / Q000473:pathology*; D008940:Mitotic Index / Q000187:drug effects; D009940:Organoids / Q000187:drug effects / Q000473:pathology; D010704:Phorbols / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
chemical_list: D006131:Growth Inhibitors; D008235:Lyngbya Toxins; D010704:Phorbols; D004247:DNA; C022229:dihydroteleocidin B; D013755:Tetradecanoylphorbol Acetate