Extracellular calcium stimulates DNA synthesis in synergism with zinc, insulin and insulin-like growth factor I in fibroblasts.
In serum-starved mouse NIH 3T3 fibroblasts cultured in 1.8 mM Ca2+-containing medium, addition of 0.75-2 mM extra Ca2+ stimulated DNA synthesis in synergism with zinc (15-60 microM), insulin and insulin-like growth factor I. Extra Ca2+ stimulated phosphorylation/activation of p42/p44 mitogen-activated protein kinases by an initially (10 min) zinc-independent mechanism; however, insulin, and particularly zinc, significantly prolonged Ca2+-induced mitogen-activated protein kinase phosphorylation. In addition, extra Ca2+ activated p70 S6 kinase by a zinc-dependent mechanism and enhanced the stimulatory effect of zinc on choline kinase activity. Insulin and insulin-like growth factor I also commonly increased both p70 S6 kinase and choline kinase activities. In support of the role of the choline kinase product phosphocholine in the mediation of mitogenic Ca2+ effects, cotreatments with the choline kinase substrate choline (250 microM) and the choline kinase inhibitor hemicholinium-3 (2 mM) enhanced and inhibited, respectively, the combined stimulatory effect of extra Ca2+ (3.8 mM total) and zinc on DNA synthesis. In various human skin fibroblast lines, 1-2 mM extra Ca2+ also stimulated DNA synthesis in synergism with zinc and insulin. The results show that in various fibroblast cultures, high concentrations of extracellular Ca2+ can collaborate with zinc and certain growth factors to stimulate DNA synthesis. Considering the high concentration of extracellular Ca2+ in the dermal layer, Ca2+ may promote fibroblast growth during wound healing in concert with zinc, insulin growth factor-I insulin, and perhaps other growth factors.
Huang
J S
JS
The Hormel Institute, University of Minnesota, Austin, MN, USA.
Mukherjee
J J
JJ
Chung
T
T
Crilly
K S
KS
Kiss
Z
Z
D016475:3T3 Cells; D000818:Animals; D002118:Calcium / Q000008:administration & dosage* / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D002797:Choline Kinase / Q000378:metabolism; D004247:DNA / Q000096:biosynthesis*; D004357:Drug Synergism; D005110:Extracellular Space / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D006426:Hemicholinium 3 / Q000494:pharmacology; D006801:Humans; D007328:Insulin / Q000008:administration & dosage*; D007334:Insulin-Like Growth Factor I / Q000008:administration & dosage*; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010767:Phosphorylcholine / Q000378:metabolism; D019893:Ribosomal Protein S6 Kinases / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D012867:Skin / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D015032:Zinc / Q000008:administration & dosage*
D007328:Insulin; D010767:Phosphorylcholine; D006426:Hemicholinium 3; D007334:Insulin-Like Growth Factor I; D004247:DNA; D002797:Choline Kinase; D019893:Ribosomal Protein S6 Kinases; D020928:Mitogen-Activated Protein Kinases; D015032:Zinc; D002118:Calcium