Effect of Tea Polyphenols on the Adhesion of Highly Metastatic Human Lung Carcinoma Cell Lines to Endothelial Cells in Vitro

AIM: Tea polyphenols are known to play roles in critical steps of human lung carcinoma cell metastasis. For understanding the mechanisms whereby they inhibit tumor metastasis, the present study was conducted to investigate their effects on the adhesion of highly metastatic lung carcinoma cell lines (PG cells) to endothelial cells (EC cells) and adhesion molecule expression in vitro. METHODS: The expression of CD44 or CD54 in the PG cells was detected by flow cytometry and adhesion of PG cells to EC cells was assessed by confocal microscopy double fluorescence staining. RESULTS: The results showed that tea polyphenols: (1) inhibited the expression of CD44 and CD54, two important adhesion molecules in the PG cells in a dose-dependent manner; (2) significantly blocked the adhesion of PG cells to EC cells not only in a state of rest but also when active; and (3) influenced CD44 and CD54 expression during the adhesion process of PG cells to EC cells. CONCLUSION: The data indicated that the blocking role of tea polyphenols in the adhesion of PG cells to EC cells is related to CD44 and CD54. The mechanism of tea polyphenol prevention of human lung carcinoma metastasis might be through inhibiting adhesion molecule expression to block cancer cell adhesion.