Analysis of Interieukin-8 Gene Promoter function in Human Osteoblast-like Cells : Regulation by Ca^ -signaling and Cyclosporin A

We previously reported that an increase in intracellular calcium by calcium ionophore (A23187) and 4β-phorbol-12β-myristate-13a-acetate (PMA) induced the expression of IL-8 mRNA in human osteoblast-like HOS-TE85 cells andthis induction was markedly suppressed by cyclosporin A (CsA). In this study we investigated whether the regulation by A23187, PMA and CsA was occured at a transcriptional level by reporter gene assays. A promoter region spanning from -1460 to +40 of IL-8 gene was PCR-amplified and inserted upstream of a luciferase reporter gene. Various deletion mutants were also constructed. Transfection of the plasmids into HOS-TE85 cells demonstrated that the nucleotides between -133 and -60 base pairs upstream of IL-8 gene are essential and sufficient for its induction by A23187/PMA, and suppression of this induction by CsA.