title: The proapoptotic protein Bim is up regulated by 1α,25-dihydroxyvitamin D3 and its receptor agonist in endothelial cells and transformed by viral GPCR associated to Kaposi sarcoma.
abstract: We have previously shown that 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3] and its less calcemic analog TX 527 induce apoptosis via caspase-3 activation in endothelial cells (SVEC) and endothelial cells transformed by the viral G protein-coupled receptor associated to Kaposi sarcoma (vGPCR). In this work, we studied whether intrinsic apoptotic pathway could be activated by changing the balance between anti and pro-apoptotic proteins. Time response qRT-PCR analysis demonstrated that the mRNA level of anti-apoptotic gene Bcl-2 decreased after 12h and increased after 48h treatment with 1α,25(OH)2D3 or TX 527 in SVEC and vGPCR cells, whereas its protein level remained unchanged through time. mRNA levels of pro-apoptotic gene Bax significantly increased only in SVEC after 24 and 48h treatment with 1α,25(OH)2D3 and TX 527 although its protein levels remained unchanged in both cell lines. Bim mRNA and protein levels increased in SVEC and vGPCR cells. Bim protein increase by 1α,25(OH)2D3 and TX 527 was abolished when the expression of vitamin D receptor (VDR) was suppressed. On the other hand, Bortezomib (0.25-1nM), an inhibitor of NF-κB pathway highly activated in vGPCR cells, increased Bim protein levels and induced caspase-3 cleavage. Altogether, these results indicate that 1α,25(OH)2D3 and TX 527 trigger apoptosis by Bim protein increase which turns into the activation of caspase-3 in SVEC and vGPCR cells. Moreover, this effect is mediated by VDR and involves NF-κB pathway inhibition in vGPCR.
authors.affiliation: INBIOSUR (CONICET-UNS), 8000 Bahía Blanca, Argentina.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Suares
authors.affiliation: INBIOSUR (CONICET-UNS), 8000 Bahía Blanca, Argentina.
authors.forename: Ana
authors.initials: A
authors.lastname: Russo de Boland
authors.affiliation: Laboratory of Clinical and Experimental Endocrinology, KU Leuven, B-3000 Leuven, Belgium.
authors.forename: Annemieke
authors.initials: A
authors.lastname: Verstuyf
authors.affiliation: INBIOSUR (CONICET-UNS), 8000 Bahía Blanca, Argentina.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Boland
authors.affiliation: INBIOSUR (CONICET-UNS), 8000 Bahía Blanca, Argentina. Electronic address: vgpardo@criba.edu.ar.
authors.forename: Verónica
authors.initials: V
authors.lastname: González-Pardo
mesh_terms: D000480:Alkynes / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000096:biosynthesis*; D000072224:Bcl-2-Like Protein 11; D002117:Calcitriol / Q000494:pharmacology*; D053148:Caspase 3 / Q000378:metabolism; D002461:Cell Line, Transformed; D002762:Cholecalciferol / Q000494:pharmacology; D042783:Endothelial Cells / Q000378:metabolism*; D019288:Herpesvirus 8, Human / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000096:biosynthesis*; D051379:Mice; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis*; D043562:Receptors, G-Protein-Coupled / Q000819:agonists* / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D000480:Alkynes; D051017:Apoptosis Regulatory Proteins; C000606775:BCL2L11 protein, human; D000072224:Bcl-2-Like Protein 11; C000606776:Bcl2l11 protein, mouse; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D043562:Receptors, G-Protein-Coupled; D014764:Viral Proteins; C409043:inecalcitol; D002762:Cholecalciferol; C505409:Casp3 protein, mouse; D053148:Caspase 3; D002117:Calcitriol
keywords: Bax; Bcl-2; Bim; Kaposi sarcoma; Vitamin D compounds; Vitamin D receptor