Transforming growth factor-β enhances calcitonin-induced cyclic AMP production and the number of calcitonin receptors in long-term cultures of human umbilical cord blood monocytes in the presence of 1,25-dihydroxycholecalciferol
✍ Scribed by Gabriel Mbalaviele; Philippe Orcel; Zhor Bouizar; Annick Jullienne; Marie Christine De Vernejoul
- Publisher
- John Wiley and Sons
- Year
- 1992
- Tongue
- English
- Weight
- 837 KB
- Volume
- 152
- Category
- Article
- ISSN
- 0021-9541
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✦ Synopsis
Insern? U349, CwiLre Viggo Petersen, Hripital Ldriboisiere, 750 10 f a r l s , France Transforming growth factor-B (TGF-P) is a multifunctional polypeptide, abundant in bone, that regulates both proliferation and differentiation of a wide variety of cells, but its rolc in osteoclast differentiation remains controversial. We havc recently shown that long-term cultures of hunian cord blood monocytes, in the presence of 1,25 dihydroxycholecalciferol (1,25-(OH),D,), give rise to cclls that express two markers of the osteoclast phenotype, namely, the vitronectin receptor (VNRj and the calcitonin reccptor (CTR). TGF-P enhanced the proportion of cells expressing the VNR.
In the present study, we investigated the effect of 1-GF-@ on the expression of CTR in cord blood monocytes cultured during 3 weeks in the presence of 1,25-(OH),D,. When added within the first 2 weeks of culture, TGF-6 (500 pgiml) significantly decreased the cell protein content. TGF-6 alone did not stimulate basal cAMP production. The 10 nM-sCT-stimulated cAMP production was enhanced by increasing TGF-P concentrations from 50 pg/ml to 1,000 pgiml: for 500 pgml TLF-6, it was 294 I 20% vs. 140 5 25% for control cultures (p < 0.01 j, The sCT dose-response curves showed a higher CAMP production from 10 ' M to 1 M of sCT in the presence of 500 p g h l TGF-(J than in control cultures. The increase was '325 + 36% in the prcscnce of TCF-p and . I 95 & 13% in the absence of TGF-(J, for 10-M sCT (p < 0.01 1. This effect of TGF-P on CAM? production was not observed either when it was added to rnonocyte cultures the last day or 2 hours before the end of the culture or in MCF7, a human breast cancer cell line that expresses CTR. ['L51]-sCT binding studies performed on