The differentiation inducer, dimethyl sulfoxide, transiently increases the intracellular calcium ion concentration in various cell types.
Dimethyl sulfoxide (DMSO) initiates a coordinated differentiation program in various cell types but the mechanism(s) by which DMSO does this is not understood. In this study, the effect of DMSO on intracellular calcium ion concentration ([Ca2+]i) was determined in primary cultures of chicken ovarian granulosa cells from the two largest preovulatory follicles of laying hens, and in three cell lines: undifferentiated P19 embryonal carcinoma cells, 3T3-L1 fibroblasts, and Friend murine erythroleukemia (MEL) cells. [Ca2+]i was measured in cells loaded with the Ca(2+)-specific fluoroprobe Fura-2. There was an immediate (i.e., within 5 sec), transient, two to sixfold increase in [Ca2+]i after exposing all cell types to 1% DMSO. DMSO was effective between 0.2 and 1%. The prompt DMSO-induced [Ca2+]i spike in all of the cell types was not prevented by incubating the cells in Ca(2+)-free medium containing 2 mM EGTA or by pretreating them with the Ca(2+)-channel blockers methoxyverapamil (D600; 100 microM), nifedipine (20 microM), or cobalt (5 mM). However, when granulosa cells, 3T3-L1 cells, or MEL cells were pretreated with lanthanum (La3+; 1 mM), which blocks both Ca2+ channels and membrane Ca2+ pumps, there was a sustained increase in [Ca2+]i in response to 1% DMSO. By contrast, pretreating P19 cells with La3+ (1 mM) did not prolong the DMSO-triggered [Ca2+]i transient. In all cases, the DMSO-induced [Ca2+]i surge was unaffected by pretreating the cells with the inhibitors of inositol phospholipid hydrolysis, neomycin (1.5 mM) or U-73, 122 (2.5 microM). These results suggest that DMSO almost instantaneously triggers the release of Ca2+ from intracellular stores through a common mechanism in cells in primary cultures and in cells of a variety of established lines, but this release is not mediated through phosphoinositide breakdown. This large, DMSO-induced Ca2+ spike may play a role in the induction of cell differentiation by DMSO.
Morley
P
P
Cell Signals Group, Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario.
Whitfield
J F
JF
D000818:Animals; D002118:Calcium / Q000032:analysis / Q000378:metabolism*; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D002645:Chickens; D003035:Cobalt / Q000494:pharmacology; D004121:Dimethyl Sulfoxide / Q000494:pharmacology*; D005260:Female; D005347:Fibroblasts / Q000737:chemistry / Q000166:cytology / Q000378:metabolism*; D005456:Fluorescent Dyes; D016257:Fura-2; D005711:Gallopamil / Q000494:pharmacology; D006107:Granulosa Cells / Q000737:chemistry / Q000166:cytology / Q000378:metabolism*; D007811:Lanthanum / Q000494:pharmacology; D004915:Leukemia, Erythroblastic, Acute / Q000378:metabolism / Q000473:pathology; D051379:Mice; D009355:Neomycin / Q000494:pharmacology; D009543:Nifedipine / Q000494:pharmacology; D013724:Teratoma / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D014407:Tumor Cells, Cultured
D015220:Calcium Channels; D005456:Fluorescent Dyes; D005711:Gallopamil; D003035:Cobalt; D007811:Lanthanum; D009355:Neomycin; D009543:Nifedipine; D002118:Calcium; D016257:Fura-2; D004121:Dimethyl Sulfoxide