RNA interference against peroxisome proliferator-activated receptor delta gene promotes proliferation of human colorectal cancer cells.

Abstract

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. 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. 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. PPAR delta may inhibit the proliferation of CRC cells and increase the number of cells in G1 phase, without any function in cell apoptosis.