Proliferation of human peripheral blood mononuclear cells during calcium entry blockade. Role of protein kinase C.
To evaluate the role of protein kinase C (PKC) and intracellular calcium and particularly Ca(2+)-uptake in the initiation of lymphocyte mitogenesis, the proliferation of human peripheral blood mononuclear cells (PBMC) was investigated during calcium entry blockade with nifedipine (an L-type calcium channel blocker) and mibefradil (an L- and T-type calcium channel blocker with a higher selectivity for T-type channels). The rate of [3H]-thymidine, [3H]-uridine and [3H]-leucine incorporation into control and concanavalin A-stimulated PBMC cultured for 3 days in the presence or absence of the calcium channel blockers nifedipine or mibefradil (1, 10 or 50 microM) is assayed. Nifedipine and mibefradil concentration-dependently reduced cell number and [3H]-thymidine incorporation or de novo DNA synthesis in control and concanavalin A-stimulated PBMC, as well as de novo RNA and protein synthesis. The proliferative response of nifedipine- or mibefradil-treated cells was restored by addition of phorbol-12-myristate-13-acetate (PMA), an exogenous PKC activator. Our data show that PBMC treated with the Ca2+ channel blockers nifedipine or mibefradil are still capable of proliferating in response to PMA. However, in PKC-depleted cells, the proliferative response of PBMC was suppressed.
Department of Molecular and Cardiovascular Research, Faculty of Medicine, University of Leuven (KU Leuven), Belgium. paul.lijnen@med.kuleuven.ac.be
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D000328:Adult; D001562:Benzimidazoles / Q000494:pharmacology / Q000633:toxicity; D002121:Calcium Channel Blockers / Q000494:pharmacology* / Q000633:toxicity; D002455:Cell Division / Q000187:drug effects; D003208:Concanavalin A / Q000494:pharmacology; D004247:DNA / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000032:analysis; D007930:Leucine / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000187:drug effects*; D008297:Male; D020748:Mibefradil; D009543:Nifedipine / Q000494:pharmacology / Q000633:toxicity; D011493:Protein Kinase C / Q000502:physiology*; D011741:Pyrimidine Nucleosides / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013764:Tetrahydronaphthalenes / Q000494:pharmacology / Q000633:toxicity; D013936:Thymidine / Q000378:metabolism; D014529:Uridine / Q000378:metabolism
D001562:Benzimidazoles; D002121:Calcium Channel Blockers; D011741:Pyrimidine Nucleosides; D013764:Tetrahydronaphthalenes; D003208:Concanavalin A; D020748:Mibefradil; D004247:DNA; D007770:L-Lactate Dehydrogenase; D011493:Protein Kinase C; D007930:Leucine; D009543:Nifedipine; D013755:Tetradecanoylphorbol Acetate; D013936:Thymidine; D014529:Uridine