Effect of phorbol and bryostatin I on chondrogenic expression of chick limb bud, in vitro.
Garrison-JC; Pettit-GR; Uyeki-EM
Life Sci 1987 Oct; 41(17):2055-2061
The effect of phorbol-12-myristate-13-acetate (16561298) (PMA) on chondrogenesis was studied in chick limb bud cells. The effect of bryostatin-I (83314016) was examined for comparison purposes. Limb bud cells harvested from stage 23 or 24 White-Leghorn-chick embryos were incubated with up to 10(-6) molar (M) PMA or 10(-7)M bryostatin- I alone or in combination for up to 96 hours. The effects on cell proliferation were determined using a Coulter channelyzer. The effects on chondrogenesis were assessed by determining the extent of cartilage nodule formation and Alcian-blue dye staining for chondroitin-sulfate. Four days' exposure to 10(-7)M or higher PMA caused a significant decrease in cartilage nodule formation and the amount of Alcian-blue staining. No effects on cell proliferation were observed. When examined according to incubation time, the greatest inhibition of chondrogenesis occurred after 49 to 96 hours of PMA treatment. Bryostatin-I had a slight stimulatory effect on cartilage nodule dye formation and Alcian-blue staining. Coincubation of 10(-7)M bryostatin-I with 10(-7)M PMA abolished the inhibitory effect of PMA on chondrogenesis. The authors conclude that the inhibitory effect of PMA on chondrogenesis is due to a suppression of chondrocyte phenotypic expression rather than cell commitment to chondrocytic expression. Since both PMA and bryostatin-I are protein-C-kinase activators, the mechanism of PMA induced chondrogenesis inhibition must involve processes other than protein-C-kinase activation.
NIOSH-Publication; NIOSH-Grant; Grants-other; Biokinetics; Histochemical-analysis; Dose-response; Enzyme-activity; In-vitro-studies; Laboratory-animals; Growth-inhibition
Pharmacology University of Kansas 39Th St at Rainbow Blvd Kansas City, Kansas 66103
University of Kansas Col Hlth Sci & Hosp, Kansas City, Kansas