COX2 regulation by 1α,25(OH)2D3 VDR ligand in endothelial cells expressing vGPCR

ALEJANDRA SUARES; CINTHYA TAPIA; VERONICA GONZALEZ PARDO; GABRIELA ALEJANDRA SALVADOR

Buenos Aires

Congreso; Reunion conjunta de sociedades de Biociencias; 2017

The Kaposi?s Sarcoma-associated Herpes virus G Protein-Coupled Receptor (vGPCR) is a key molecule in the pathogenesis of Kaposi Sarcoma.1α,25(OH)2D3anti-proliferative impact in vGPCR cells occur in part byNF-κB pathway negative modulation, family of conserved transcription factors critical during the pro-inflammatory response. In this work, we studied if COX-2 regulation by 1α,25(OH)2D3 in vGPCR cells contributes totheanti-inflammatory action. As we have previously reported vGPCR cell proliferationis inhibited by 1α,25(OH)2D3 (10 nM, 48 h) due to a reduction on cells number, PLA2 inhibitor ATK (10-20µM) or the COX-2 inhibitor Celecoxib (10-20µM) decreases vGPCR cell number in a dose dependentmanner,similarly to 1α,25(OH)2D3.These changes are accompanied by morphological modificationsobserved at the microscope.qRT-PCR analysis of COX-2 gene expression revealed a mRNA increase within 20 min of 1α,25(OH)2D3 treatment and remains increased at least for 72 h.Moreover, ATK inhibitor (20µM) could not counteract COX-2 mRNA induced by 1α,25(OH)2D3 (10 nM, 24h).Finally,COX-2 VDR dependence was evaluated using the stable VDR knock-down cell line vGPCR-shVDR; COX-2mRNA increment by 1α,25(OH)2D3is found impaired in these cells. Significant differences of the data between control (vehicle) and treated conditions were analyzed by one way-ANOVA followed by Bonferroni test or t-test (*p< 0.05, **p