Stable expression of the calbindin-D28K complementary DNA interferes with the apoptotic pathway in lymphocytes.
The WEHI7.2 thymoma cell line undergoes apoptotic cell death when exposed to glucocorticoids and agents that increase intracellular cAMP. Several lines of evidence indicate that calcium may play an important role in events culminating in lymphocyte apoptosis. In these studies, calbindin-D28K was stably overexpressed in WEHI7.2 cells to determine if increasing the Ca(2+)-binding capacity of the cell interferes with the apoptotic pathway. Indeed, stable expression of calbindin-D28K decreased the apoptotic effects of dexamethasone and forskolin, and the level of resistance to these agents correlated with the relative amount of calbindin expressed in each line. Overexpression of calbindin also increased cell survival in the presence of the calcium ionophore A23187. The stably expressed calcium-binding protein appeared to exert its protective effect subsequent to transcriptional activation, since glucocorticoid- and cAMP-induced gene expression were not affected. These data support the proposal that calcium fluxes are involved in apoptosis and suggest that high level expression of proteins that buffer calcium fluxes can effectively suppress death in apoptosis-susceptible cells.
Dowd
D R
DR
Department of Biochemistry, University of Arizona, Tucson 85724.
MacDonald
P N
PN
Komm
B S
BS
Haussler
M R
MR
Miesfeld
R L
RL
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D064092:Calbindin 1; D064026:Calbindins; D000001:Calcimycin / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000494:pharmacology; D003864:Depression, Chemical; D003907:Dexamethasone / Q000494:pharmacology; D008214:Lymphocytes / Q000187:drug effects*; D051379:Mice; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000473:pathology; D011993:Recombinant Fusion Proteins / Q000494:pharmacology; D064030:S100 Calcium Binding Protein G / Q000096:biosynthesis / Q000494:pharmacology*; D013945:Thymoma / Q000473:pathology; D013953:Thymus Neoplasms / Q000473:pathology; D014407:Tumor Cells, Cultured
C576499:Calb1 protein, mouse; D064092:Calbindin 1; D064026:Calbindins; D011993:Recombinant Fusion Proteins; D064030:S100 Calcium Binding Protein G; D005576:Colforsin; D000001:Calcimycin; D003907:Dexamethasone; D000242:Cyclic AMP