Influence of paeonol on expression of COX-2 and p27 in HT-29 cells.

AIM To investigate the effect of paeonol on controlling the proliferation of colorectal cancer cell line HT-29 and to discuss its possible mechanism. METHODS The inhibitory effect of paeonol on proliferation of HT-29 cells was detected by MTT assay. The results of apoptosis were measured by flow cytometry. Immunocytochemical staining was performed to detect the expression of cyclooxygenase-2 (COX-2) and protein p27 in HT-29 cells treated with paeonol at different concentrations. Reverse transcription-polymerase chain reaction (RT-PCR) was used for mRNA analysis. RESULTS From the data of both MTT and flow cytometry, we observed that cell proliferation was inhibited by different concentrations of paeonol. By immunocytochemical staining, we found that HT-29 cells treated with paeonol (0.024-1.504 mmol/L) reflected reduced expression of COX-2 and increased expression of p27 in a dose-dependent manner. RT-PCR showed that paeonol down-regulated COX-2 and up-regulated p27 in a dose- and time-dependent manner in HT-29 cells. CONCLUSION One of the apoptotic mechanisms of paeonol is down-regulation of COX-2. p27 is up-regulated simultaneously and plays an important part in controlling cell proliferation and is a crucial factor in the Fas/FasL apoptosis pathway.