Quantification of (–)-Epigallocatechin-3-gallate Inhibition of Anaplastic Thyroid Cancer Cell Line Adhesion and Proliferation Using Real-time Cell Analysis

Anaplastic thyroid cancer (ATC) has a poor prognosis because of immediate metastasis. Several studies in humans and animals have suggested that the ingestion of green tea or its active ingredient (–)-epigallocatechin-3-gallate (EGCG) may decrease the risk of cancer. Using a recently developed real-time cell analysis (RTCA) system, we have shown previously that EGCG inhibits cell migration and the invasion of oral cavity cancers by suppressing matrix metalloproteinases. In the present study we used RTCA to investigate the effects of EGCG on cell adhesion to fibronectin-coated plates using three cancer cell lines: one ATC cell line (TCO-1) and two poorly differentiated oral squamous cell carcinomas (OSCCs) cell lines (SAS and HO-1-u-1; originating from the tongue and floor of the mouth, respectively). EGCG (50µM) inhibited the adhesion of all three cell lines. In addition to its effects on cell adhesion, 50µM EGCG inhibited the cell proliferation of TCO-1 cells. Furthermore, EGCG decreased αV integrin (ITGAV) mRNA levels in all three cell lines, suggesting that EGCG inhibits the cell adhesion and proliferation of OSCC and ATC cells via suppression of integrin expression. Therefore, EGCG represents a useful dietary constituent or a lead compound for counteracting metastasis of oral cavity cancers and thyroid cancers.