The Effects Of Paeonol On Apoptosis, Proliferation Of Human Colorectal Cancer Cell Line HT-29 And Its Molecule Mechanism

Objective: To investigate the effects of paeonol(Pae) in inhibiting proliferation of HT-29 cells and inducing its apoptosis and the possible molecule mechanism, and provide the theoretic basis for new colorectal cancer therapy.Methods: The inhibitory effect of Paeonol, 5-FU, MMC, DDP with different concentration on human colorectal cancer cell line in vitro were detected by MTT assay, and the synergetic effect of Paeonol at low concentration with chemotherapy agents was observed. The induction of apoptosis and the influence on the distribution of HT-29 cell cycle were measured by flow cytometry. The expression of apoptosis associated genes bcl-2, bax and p53 was observed by immunocytochemical staining. Results: Pae at the concentration of 7.81²50mg/L could inhibit the proliferation of HT-29 cells, which showed obvious concentration-effect and time-effect relationship, and the highest inhibition rate was 91.849% (P<0.01) . Pae at low concentration with several chemotherapy agents, especially with 5-FU, had synergetic effect in inhibiting the proliferation of HT-29 cells. Pae at the concentration of 15.63mg/L, 62.5mg/L and 250mg/L could induce apoptosis of HT-29 cells after 48h. By flow cytometry methods, the apoptosis rates of HT-29 cells were 7.6%, 16.2% and 34.5% respectively, which showed obvious concentration-effect relationship. The cell cycle distribution was altered simultaneously. S phase of the cells were increased , while G₀/G₁ and G₂/M phase of the cells were decreased after treated by Pae. Immunocytochemical staining showed that the expression of bcl-2 and p53 protein was decreased significantly while the expression of bax protein had no significant change on HT-29 cells after treated by Pae.Conclusions: Pae may inhibit proliferation of HT-29 cells, which showed obvious concentration-effect and time-effect relationship. Pae had synergetic antitumor effect with cell cycle specific chemotherapy agents. Pae could induce apoptosis of HT-29 cells. The possible mechanism is the influence in distribution of cancer cell cycle , down-regulation the ratio of bcl-2/bax and the expression of p53 protein.