ABSTRACT
Objective: To compare effects of sulindac, PPAR? activator and PPAR? antagonist on the proliferation and apoptosis of the colonic cancer cells, and to investigate whether sulindac exerts its colonic neoplasm inhibiting activity through pathway of PPAR?. Methods: Cell strain HT-29 of colonic cancer was divided into six groups: the control group, sulindac group, 15d-PGJ2 (PPAR? activator) group, GW9662 (PPAR? antagonist) group, sulindac+GW9662 group and 15d-PGJ2+ GW9662 group. After 24 and 48 hours’culturing, proliferation status of each group was determined by immunocytochemical staining of PCNA, and cell apoptosis status was determined by double staining method of AnnexinV-FITC/PI, examined on flow cytometer. Results: (1) Proliferation status of the colonic cancer cells of each group: 24 and 48 hours after medication, PCNA positive ratios were 33.2%?4.5% and 25.0%?4.7% of the control group, 11.8%?3.7% and 8.6%?1.9% of sulindac group, 11.2%?2.5% and 11.4%?2.1% of 15d-PGJ2 group, 35.3%?4.3% and 26.8%?3.9% of GW9662 group, 16.5%?5.3% and 12.2 %?2.4% of sulindac + GW9662 group, 21.0%?4.8% and 21.5%?4.2% of 15d-PGJ2+GW9662 group. (2) Apoptosis ratio of colonic cancer cells of each group: 24 hours after medication, apoptosis rate of colonic cancer cells was 13.0%?1.0% of the control group, 41.0%? 2.6% of sulindac group, 11.5%?0.6% of 15d-PGJ2 group, 12.4%?0.9% of GW9662 group, 33.6%?2.3% of sulindac+GW9662 group, and 13.0%?1.0% of 15d-PGJ2 + GW9662 group. 48 hours after medication, apoptosis rate was 14.0%?3.4% of the control group, 95.3%?1.5% of sulindac group, 31.5%?2.3% of 15d-PGJ2 group, 13.0%?1.9% of GW9662 group, 86.8%?0.4% of sulindac+GW9662 group, and 12.9%?1.0% of 15d-PGJ2+GW9662 group. Conclusion: Both sulindac and PPAR? activator can inhibit proliferation and promote apoptosis of colonic cancer cells, and their effects can be antagonized by PPAR? antagonist, which indicates that as a kind of PPAR? ligand, sulindac can inhibit proliferation of colonic cancer cells via activating PPAR?.
ABSTRACT
Several M-CAT elements are present in the chicken nicotinic acetylcholine receptor γ-subunit promoter and required for the totipotency of this gene.To understand the binding properties of M-CAT element,the interaction of M-CAT motif,at the position -67/-61 relative to the initiation site of γ-promoter with nuclear proteins,were analyzed.Mutageneses and binding experiments demonstrated that the M-CAT core motif bound nuclear protein (s) from tested chicken tissues to generate a high-mobility complex;while the flanking sequence bound different factors to generate lower-mobility complexes with the exception of liver.Southwestern blotting showed that only a 30 kD protein was expressed in tested tissues of chicken embryo at day 13.These results suggest that a 30 kD factor can directly bind to M-CAT element in the manner of monomer,even homodimer and is ubiquitously expressed in tissues,while the binding of the factor(s) to flanking sequence should probably rely on the presence of a 30 kD ubiquitous factor.
