1,25 Dihydroxyvitamin D sub(3) Activates Sphingomyelin Turnover in ROS17/2.8 Osteosarcoma Cells without Sphingolipid-Induced Changes in Cytosolic Ca super(2+)

• Published in: Biochemical and biophysical research communications Vol. 273; no. 1; pp. 95 - 100
• Main Authors: Liu, Riting, Xu, Yihuan, Farach-Carson, Mary C, Vogel, James J, Karin, Norman J
• Format: Journal Article
• Language: English
• Published: 24.06.2000
• ISSN: 0006-291X
• DOI: 10.1006/bbrc.2000.2905

1,25-Dihydroxyvitamin D sub(3) [1,25(OH) sub(2)D sub(3)] initiates the hydrolysis of sphingomyelin in ROS 17/2.8 osteosarcoma cells with the resultant generation of cell-associated ceramide. Increases in ceramide levels were detectable at 15 min and maximal one hour after exposure of cells to 1,25(OH) sub(2)D sub(3). Neither 1,25(OH) sub(2)D sub(3) nor exogenous ceramide elicited a change in cytosolic free Ca super(2+) ([Ca super(2+)] sub(i)). Transient elevations in [Ca super(2+)] sub(i) were observed when cells were exposed to exogenous sphingosine, but there was no detectable conversion of ceramide to sphingosine in 1,25(OH) sub(2)D sub(3)-treated cells. Ceramide also did not stimulate Ca super(2+) uptake across ROS 17/2.8 cell plasma membranes. Collectively, these results suggest that 1,25(OH) sub(2)D sub(3) activates sphingomyelin turnover in ROS 17/2.8 osteosarcoma cells but that the sphingolipid metabolite ceramide is not responsible for 1,25(OH) sub(2)D sub(3)-induced activation of plasma membrane Ca super(2+) channels.