Over-expression of LXRα regulates dexamethasone-stimulated GR transcriptional activity in a gene promoter-specific way.

<p>A and B. Over-expression of LXRα/RXRα suppresses dexamethasone-stimulated transcriptional activity of the PEPCK (A) but not the GILZ (B) promoter. HCT116 cells were transfected with pPEPCK-luc (A) or pGILZ-Luc (B), together with pGL4.73[<i>hRluc</i>/SV40] and pRShGRα in the presence or absence of pCMX-hLXRα and pCMX-hRXRα, and were incubated with or without 10⁻⁶ M dexamethasone and/or 10⁻⁶ M GW3965. Bars represent mean ± S.E. values of the firefly luciferase activity normalized for the renilla luciferase activity. *: p<0.01, n.s.: not significant between the two conditions indicated. Dex: dexamethasone, RLA: relative luciferase activity. C. Over-expression of LXRα/RXRα does not affect dexamethasone-induced repression of the transcriptional activity of NF-κB. HCT116 cells were transfected with (κB)₃-Luc and pGL4.73[<i>hRluc</i>/SV40] in the presence or absence of pRSV-RelA (p65)/pRSV-NF-κBI (p50), pRShGRα, and pCMX-hLXRα and pCMX-hRXRα, and were incubated with or without 10⁻⁶ M dexamethasone. Bars represent mean ± S.E. values of the firefly luciferase activity normalized for the renilla luciferase activity. *: p<0.01, n.s.: not significant, compared to the condition obtained in the absence of p65/p50 and dexamethasone treatment, or between the two conditions indicated. Dex: dexamethasone, RLA: relative luciferase activity.