Effects Of EGCG On The Growth Inhibition And HTERT Expression Of Human Lung Adenocarcinoma A549Cells

Objective:To investigate the effects of (-)-epigallocatechin-3-gallate (EGCG) on proliferation and apoptosis and the expression of human telomerase reverse transcriptase (hTERT) of human lung adenocarcinoma cell line A549, thus provide a theoretical basis for the EGCG treatment in lung neoplasm. Methods:1. A549cells were allocated into6groups and treated with0,50,100,150,200,250mg/L EGCG for24,48,72h, respectively. MTT assay was used to determine the inhibitory rate of cell proliferation.2. After treated with different concentrations of EGCG (0、100、200、250mg/L) for48h, the morphological changes of A549cells were observed by inverted microscope.3. Flow Cytometry with AnnexinV-FITC,PI double staining was employed to analyze the apoptosis of A549cells treated with various concentrations of EGCG (O、100、200、250mg/L) for48h. 4. RT-PCR was applied to detect the mRNA expression of hTERT(48h later).5. The expression of hTERT protein was identified by immunocytochemistry(48h later).Results:1. MTT assay showed that EGCG could significantly inhibit the proliferation of A549cells,when A549dealing with various concentrations of EGCG (50,100,150,200,250mg/L), compared with the control group (F=185.94,291.23,4186.12,P均<0.01). The inhabition ratio of cell proliferation was gradually elevated with the increasing concertration of EGCG and the elongation of time, which presenting obvious time-dose dependent manner.2. The A549cells became roll and small after48h exposure to EGCG, but control group cells were still polygon, cell outlines was clear and growth was vigorous. When increasing the concentration of EGCG, some floating and dead cells could be seen under the inverted microscopy.3. Flow cytometry results showed that EGCG could promote the apoptosis of A549cells. When A549cells dealing with different concentrations of EGCG (0,100,200,250mg/L), the apoptosis rate of A549cells were (6.17±0.64)%,(12.50±0.50)%,(26.22±0.64)%,(46.47±0.56)%, respectively. Compared with the control group, the apoptosis rate of A549cells treated with EGCG raised up significantly(F=2757.18, P<0.05).4. EGCG could suppress the mRNA expression of hTERT in a dose-dependent manner after treated with various concentrations of EGCG for48h.5. The expression of hTERT protein was down-regulated by immunocytochemical method after exposured to various concentrations of EGCG for48h. Conclusion:EGCG can effectively inhibit cell proliferation and induce apoptosis of A549cells, which may be associated with downregulation of hTERT expression.