In order to explore the teaching methods of biochemistry experiment teaching,Biochemistry department of Wannan medical college adopts PBL and case-based teaching contrast to lecture based learning in exerimental course,to evaluate teaching effect by analyzing questionnaire survey associated examination results.It is shown that PBL and case-based teaching can get good teaching effect.

OBJECTIVE: To investigate the mechanism by which epigallocatechin gallate (EGCG) induces gene demethylation and promotes the apoptosis of acute myeloid leukemia KG-1 and THP-1 cell lines. METHODS: KG-1 and THP-1 cells treated with 25, 50, 75, 100 or 150 μg/mL EGCG for 48 h were examined for gene methylation using MSP and for cell proliferation using MTT assay. The changes in cell cycle and apoptosis of the two cell lines after treatment with EGCG for 48 h were detected using flow cytometry. The mRNA and protein expressions of DNMT1, CHD5, p19, p53 and p21 in the cells were detected using RT-quantitative PCR and Western blot. RESULTS: EGCG dose-dependently reversed hypermethylation of gene and reduced the cell viability in both KG-1 and THP-1 cells ( < 0.05). EGCG treatment caused obvious cell cycle arrest in G1 phase, significantly increased cell apoptosis, downregulated the expression of DNMT1 and upregulated the expressions of CHD5, p19, p53 and p21 in KG-1 and THP-1 cells ( < 0.05). CONCLUSIONS EGCG reduces hypermethylation of gene in KG-1 and THP-1 cells by downregulating DNMT1 to restore its expression, which results in upregulated expressions of p19, p53 and p21 and induces cell apoptosis.