Nitric oxide-induced cytostasis and cell cycle arrest of a human breast cancer cell line (MDA-MB-231): potential role of cyclin D1.
DETA-NONOate, a nitric oxide (NO) donor, induced cytostasis in the human breast cancer cells MDA-MB-231, and the cells were arrested in the G(1) phase of the cell cycle. This cytostatic effect of the NO donor was associated with the down-regulation of cyclin D1 and hypophosphorylation of the retinoblastoma protein. No changes in the levels of cyclin E or the catalytic partners of these cyclins, CDK2, CDK4, or CDK6, were observed. This NO-induced cytostasis and decrease in cyclin D1 was reversible for up to 48 h of DETA-NONOate (1 mM) treatment. DETA-NONOate (1 mM) produced a steady-state concentration of 0.5 microM of NO over a 24-h period. Synchronized population of the cells exposed to DETA-NONOate remained arrested at the G(1) phase of the cell cycle whereas untreated control cells progressed through the cell cycle after serum stimulation. The cells arrested at the G(1) phase after exposure to the NO donor had low cyclin D1 levels compared with the control cells. The levels of cyclin E and CDK4, however, were similar to the control cells. The decline in cyclin D1 protein preceded the decrease of its mRNA. This decline of cyclin D1 was due to a decrease in its synthesis induced by the NO donor and not due to an increase in its degradation. We conclude that down-regulation of cyclin D1 protein by DETA-NONOate played an important role in the cytostasis and arrest of these tumor cells in the G(1) phase of the cell cycle.
Department of Obstetrics and Gynecology and Department of Molecular and Medical Pharmacology, University of California, Los Angeles, CA 90095, USA.
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Pervin
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Singh
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Chaudhuri
D001943:Breast Neoplasms; D002453:Cell Cycle; D002455:Cell Division; D019938:Cyclin D1 / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015536:Down-Regulation; D016193:G1 Phase; D006131:Growth Inhibitors / Q000494:pharmacology; D006801:Humans; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009603:Nitroso Compounds / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D006131:Growth Inhibitors; D020030:Nitric Oxide Donors; D009603:Nitroso Compounds; D019938:Cyclin D1; C094210:2,2'-(hydroxynitrosohydrazono)bis-ethanamine; D009569:Nitric Oxide