TY - JOUR T1 - Kaposi Sarcoma–Associated Herpesvirus G Protein–Coupled Receptor Enhances Endothelial Cell Survival in Part by Upregulation of Bcl-2 JF - Ochsner Journal JO - Ochsner J SP - 66 LP - 75 VL - 13 IS - 1 AU - Elizabeth R. Abboud AU - Bryan D. Shelby AU - Magdalena Angelova AU - Anne B. Nelson AU - MaryBeth Ferris AU - Harris E. McFerrin AU - Cindy A. Morris AU - Deborah E. Sullivan Y1 - 2013/03/20 UR - http://www.ochsnerjournal.org/content/13/1/66.abstract N2 - Background Kaposi sarcoma–associated herpesvirus (KSHV) encoded G protein–coupled receptor (vGPCR) is a constitutively active lytic phase protein with significant homology to the human interleukin-8 receptor. vGPCR is necessary and sufficient to induce angiogenesis as well as the spindle cell proliferation characteristic of Kaposi sarcoma (KS) lesions. We previously demonstrated that Bcl-2, an antiapoptotic protein, is upregulated in KS lesions. The aim of this study was to determine if vGPCR enhances endothelial cell survival through upregulation of Bcl-2 expression and to elucidate the signaling pathways involved.Methods Primary human umbilical vein endothelial cells were transduced with a recombinant retrovirus expressing vGPCR and then subjected to serum starvation. Cell viability and apoptosis were analyzed by fluorescence-activated cell sorting. Bcl-2 expression was determined by real-time quantitative reverse transcription polymerase chain reaction and immunoblotting. Specific pharmacological inhibitors of phosphatidylinositol 3-kinase (PI3K)/Akt and the mammalian target of rapamycin (mTOR) were employed to elucidate the signaling pathways involved. Bcl-2 expression was knocked down using small interfering RNA (siRNA).Results Endothelial cells expressing vGPCR showed increased survival after serum starvation and upregulation of Bcl-2 messenger RNA (mRNA) and protein. The vGPCR-induced increases in both Bcl-2 mRNA and protein levels were dependent on PI3K signaling but not on mTOR. Moreover, siRNA inhibition of Bcl-2 resulted in significant abrogation of the observed vGPCR-mediated cell survival advantage.Conclusions Taken together, the results demonstrate that Bcl-2 is a mediator of vGPCR-induced endothelial cell survival and is a downstream effector of Akt in this process. ER -