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
Dr. Edwin M. Uyeki, Dept. of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, 39th and Rainbow Blvd., Kansas City, Kansas 66103
University of Kansas Col Hlth Sci & Hosp, Kansas City, Kansas