title: Cell cycle arrest and growth inhibition by the protein kinase antagonist UCN-01 in human breast carcinoma cells.
abstract: UCN-01 is a derivative of staurosporine, initially developed as a potentially selective inhibitor of the Ca(2+)- and phospholipid-dependent protein kinase C, but with the capacity to inhibit a number of tyrosine and serine/threonine kinases. UCN-01 inhibits the growth of 5 breast carcinoma cell lines with a 50% inhibitory concentration range of 30-100 nM during 6 days of continuous exposure. In MCF-7, MDA-MB453, and SK-BR-3 cells, UCN-01 is 5-fold more potent in growth inhibition than its diastereomer UCN-02, but the 2 compounds are equipotent in the inhibition of MDA-MB468 and H85787 cell growth. A differential sensitivity to a 24-h period of exposure to UCN-01 followed by drug removal and growth for 5 subsequent days was observed. The rank order for persistent inhibition of cells by UCN-01 was MCF-7, MDA-MB453 >> SK-BR-3 > H85787 > MDA-MB468. MCF-7 and MDA-MB453 cells did not resume proliferation within the 5 days after brief exposure to UCN-01. In contrast, MDA-MB468 and H85787 cells showed no net growth inhibition after a 24-h pulse of UCN-01, followed by 5 more days of growth in drug-free medium. In MDA-MB468 cells, 150 nM UCN-01 retards but does not prevent cell cycle progression through S phase, but the cells are clearly blocked from exit of G1 and entry into S. Progression through S phase is completely inhibited by 600 nM UCN-01. The development of a G1 to S block by UCN-01 in MDA-MB468 cells occurs in conjunction with inhibition of [32P]orthophosphate labeling and decreased phosphotyrosine mass of discrete cellular phosphoproteins.
authors.affiliation: Laboratory of Biological Chemistry, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: C M
authors.initials: CM
authors.lastname: Seynaeve
authors.forename: M
authors.initials: M
authors.lastname: Stetler-Stevenson
authors.forename: S
authors.initials: S
authors.lastname: Sebers
authors.forename: G
authors.initials: G
authors.lastname: Kaur
authors.forename: E A
authors.initials: EA
authors.lastname: Sausville
authors.forename: P J
authors.initials: PJ
authors.lastname: Worland
mesh_terms: D000470:Alkaloids / Q000494:pharmacology*; D001943:Breast Neoplasms / Q000188:drug therapy*; D002277:Carcinoma / Q000188:drug therapy*; D002453:Cell Cycle / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects*; D004273:DNA, Neoplasm / Q000032:analysis; D004305:Dose-Response Relationship, Drug; D005260:Female; D005434:Flow Cytometry; D006131:Growth Inhibitors / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D019000:Phosphotyrosine; D047428:Protein Kinase Inhibitors; D019311:Staurosporine / Q000031:analogs & derivatives; D013997:Time Factors; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D000470:Alkaloids; D004273:DNA, Neoplasm; D006131:Growth Inhibitors; D010750:Phosphoproteins; D047428:Protein Kinase Inhibitors; D019000:Phosphotyrosine; D014443:Tyrosine; C054852:7-hydroxystaurosporine; D019311:Staurosporine