EXPRESSION OF APOPTOTIC PROTEINS REGULATED BY VITAMIN D AGONISTS IN ENDOTHELIAL CELLS AND TRANSFORMED BY THE VIRAL G PROTEIN-COUPLED RECEPTOR ASSOCIATED TO KAPOSI SARCOMA

ALEJANDRA SUARES; VERONICA GONZALEZ PARDO; ANNEMIEKE VERSTUYF; PIERRE DE CLERCQ; ANA RUSSO DE BOLAND; RICARDO BOLAND

Chicago

Congreso; 17 th Vitammin D Workshop; 2014

We have previously shown that 1α,25(OH)2-Vitamin D3 [1α,25(OH)2D3] and its less calcemic analog TX 527 inhibit the proliferation of endothelial cells (SVEC) and transformed by the viral G protein-coupled receptor associated to Kaposi sarcoma (vGPCR) inducing apoptosis via caspase-3 activation. Since that the intrinsic apoptotic pathway could be activated by mitochondrial disruption changing the balance between pro and antipoptotic proteins we study the expression of Bcl-2, Bax and Bim at mRNA and protein levels in SVEC and vGPCR cells stimulated by 1α,25(OH)2D3 and TX 527. Time response qRT-PCR analysis of anti apoptotic protein Bcl-2 demonstrated that its mRNA level fluctuates in 1α,25(OH)2D3 and TX 527-treated SVEC and vGPCR cells whereas its protein level remain unchanged through time. Antiapoptotic protein Bax mRNA and protein level remain unchanged whereas Bim mRNA and its protein level increased in SVEC and vGPCR cells at different time points. On the other hand, Bortezomib (0.5 µM), a proteasome inhibitor that also inhibit NFkB pathway which is highly activated in vGPCR cells, increases Bim protein level and induces the cleavage of caspase 3 similarly to vitamin D agonists. All together these results show that 1α,25(OH)2D3 and TX 527 trigger apoptosis inducing and increase in Bim protein by a mechanism that involves the modulation of mRNA or/and the inhibition of the proteasome, that turns into the activation of caspase -3 through the intrinsic apoptotic pathway in endothelial cells and cells transformed by vGPCR.