Peroxisome proliferator-activated receptor expression and activation in normal human colonic epithelial cells and tubular adenomas

Objective Peroxisome proliferator-activated receptor (PPAR) ligands, widely used in type 2 diabetes treatment, have variably been shown to promote or prevent colon tumor formation in animal models and cell lines, but their role in normal human colon is unknown. The aim of this study was to determine PPARδ expression and function in normal human colonic epithelial cells and tubular adenomas. Material and methods Short-term cultures of normal human colonic epithelial cells were established from biopsies obtained in 42 patients with normal colonoscopy. PPAR and adipophilin mRNA expression was assessed by real-time RT-PCR. PPARs were activated by ligands for PPARα (Wy-14643), PPARδ (GW-501516) and PPARγ (rosiglitazone or troglitazone). Cell viability was measured using the methyltetrazoleum assay, proliferation by thymidine incorporation, and DNA profiles by flow cytometry. PPAR mRNA levels in tubular adenomas or metaplastic polyps (n=12) were compared with those in controls. Results PPARα and γ were consiste...