RNA Interference Against Peroxisome Proliferator-Activated Receptor δ Gene Promotes Proliferation of Human Colorectal Cancer Cells

Abstract

PURPOSE: This study was designed to investigate the effects of peroxisome proliferator-activated receptor delta (PPAR delta) on the proliferation and apoptosis of human colorectal cancer cells. METHODS: For RNA interfering (RNAi), HCT-116 cells were transfected with short hairpin RNA (shRNA)-expressing plasmids against PPAR delta or negative control vectors, and the stably transfected cells were selected with G418. The efficacy of RNAi was assessed by real-time reverse transcription polymerase chain reaction (RT-PCR) and Western blotting analysis. The proliferation, cell cycle, and apoptosis of HCT-116 cells treated by RNAi, compared with those containing control vectors or untreated, were analyzed respectively by using MTT (methyl thiazolyl tetrazolium), flow cytometry, and TdT (terminal deoxynucleotidyl transferase)-mediated dUTP nick end-labeling (TUNEL) assay. RESULTS: RNAi targeting PPAR delta resulted in substantial suppression of PPAR delta expression and significantly promoted the proliferation of HCT-116 cells relative to those with control vectors or untreated, obviously decreasing the frequency of G1-phase cells but had no effect on cell apoptosis. CONCLUSIONS: PPAR delta may inhibit the proliferation of CRC cells and increase the number of cells in G1 phase, without any function in cell apoptosis.