Expression of peroxisome proliferator-activated receptor gamma in renal cell carcinoma and growth inhibition by its agonists

Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) is a ligand-a ctivated transcriptional factor belonging to the steroid receptor superfami ly. It plays a role in both adipocyte differentiation and tumorgenesis. Up- date, the up-regulation of PPAR-gamma expression is a frequent occurrence i n a variety of different malignant tumors. In this study, we investigated t he expression of PPAR-gamma in human renal cell carcinoma (RCC tissues, and the role of PPAR-gamma in cell growth in human RCC-derived cell lines. Imm unohistochemistry showed a strong immunoreactive expression of PPAR-gamma i n all slides from cancer specimens. RT-PCR and Western blot analysis showed 3 RCC cell lines expressed PPAR-gamma mRNA and its protein. MTT assay in 3 RCC cells showed that the synthetic PPAR-gamma agonists thiazolidinedione compounds (pioglitazone and troglitazone) and the endogeneous PPAR-gamma li gand, 15-deoxy-Delta 12,14-prostaglandin J(2) (15dPGJ(2)) inhibited the gro wth of the RCC cells. These results suggest that PPAR-gamma may become a ne w target in the treatment of RCC. (C) 2001 Academic Press.