1078-0432622000FebClin Cancer ResEnhanced GBX2 expression stimulates growth of human prostate cancer cells via transcriptional up-regulation of the interleukin 6 gene.493497493-7Previous studies demonstrated that the GBX2 homeobox gene is consistently overexpressed in cultured human prostate cancer cell lines. In this study, the human GBX2 cDNA was cloned and a quantitative reverse transcription-PCR method used to demonstrate that GBX2 mRNA expression is enhanced in approximately 70% of human prostate cancer tissues compared with normal human prostate tissues. Purified recombinant GBX2 protein binds specifically to an ATTA motif within the promoter of the interleukin 6 (IL-6) gene. Using an antisense approach, down-regulation of the expression of GBX2 correlated with decreased expression of IL-6 and an inhibition of tumorigenicity of PC3 human prostate cancer cells. In addition, in vitro growth of the antisense clones was partially restored by exogenous addition of recombinant IL-6 protein to the culture media. These data demonstrated that enhanced GBX2 expression results in a stimulation of malignant growth of prostate cancer cells and that part of this stimulation involves up-regulation in the transcription of the IL-6 gene.GaoA CACUniversity of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pennsylvania 15213, USA. gaoac@msx.upmc.eduLouWWIsaacsJ TJTengCA 58236CANCI NIH HHSUnited StatesP30CA47904CANCI NIH HHSUnited StatesJournal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, P.H.S.