| Summary: | 碩士 === 國立中興大學 === 生物科技學研究所 === 96 === Tea is the most popular drink in the world, previous studies show that epigallocatechin gallate (EGCG) and theaflavin(TF) inhibit cell proliferation, adhesion, migration and induce apoptosis of cancer cells. However, the mechanisms underlying the effect of EGCG or theaflavin in inhibiting the growth of cancer cells are still unknown. Therefore we investigated in view of this question. At first, we established two human lung cancer cell lines: A549 and H838. Then, we applied either EGCG or TF into the cell culture medium at either (1) cell suspension treatment with agent, or (2) after cell adhesion on the dish treatment with agent, and determine cell viability by MTT assay.
We observed the cell suspension treatment with EGCG and TF exhibited time and dose-dependent inhibitory effect. However, treatment with agent after cell adhesion, the cell viability has no significant effect. Therefore, we suggested that EGCG and TF may indirect interact with the extra cellular matrix (ECM) proteins, which possibly can reduce expression of adhesion proteins. The results of the migration assay suggest that EGCG and TF may indirect interact with the extra cellular matrix (ECM) and interact with cell-cell adhesion protein. Moreover, TF could inhibit cell growth and migration of cancer cell more than EGCG did. Finally, we investigated which gene expression of cell migration adhesion proteins were affected by the treatments of EGCG and TF. We used real-time PCR to study the gene expression at mRNA levels. Our results showed that EGCG and TF affected different ECM protein gene expression. After treating with TF, the lung cancer cells increased the expression of E-cadherin, and Integrin αEβ7, while after treating with EGCG, the cancer cells only induced the gene expression of E-cadherin. The result implies that TF could increase gene expression of E-cadherin and Integrin αEβ7, which could enhance cell-cell adhesion and subsequently reduce cancer cell metastasis. Wstern blots and immunostaining are necessary to further confirm the observations.
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