Calcium-dependent c-myc proto-oncogene expression and proliferation of Caco-2 cells: a role for a luminal extracellular calcium-sensing receptor.
Biochem Biophys Res Commun
; 232(1): 80-3, 1997 Mar 06.
Article
in En
| MEDLINE
| ID: mdl-9125156
ABSTRACT
The human colonic cell line Caco-2 responds to a reduction of ambient [Ca++]o to levels at and below 0.25 mM by a twofold increase in [3H]thymidine labelling of their DNA. [Ca++]o signals sensed preferentially across the luminal aspect of Caco-2 cells, are rapidly (4 h) transduced via PKC activation into up to sixfold increases in c-myc expression. This suggests the presence of a [Ca++]o-sensing membrane receptor (CaR) similar to that described by Brown et al. (1) in parathyroid and kidney cells. By RT-PCR we were able to amplify a 426 bp fragment from Caco-2 mRNA with 98% nucleotide identity to a part of the coding region for the extracellular domain of the parathyroid CaR. Immunohistochemical staining with a monoclonal antiparathyroid CaR antibody demonstrates CaR protein at the plasma membrane of confluent Caco-2 cells. Our results imply that the intestinal CaR is a potential mediator for the transduction of low luminal [Ca++]o into tumor promoting signals in human colonocytes.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Cell Division
/
Gene Expression Regulation
/
Calcium
/
Genes, myc
/
Receptors, Cell Surface
Limits:
Humans
Language:
En
Journal:
Biochem Biophys Res Commun
Year:
1997
Document type:
Article
Affiliation country:
Austria