(−)-Epigallocatechin-3-gallate (EGCG), a major green tea polyphenol, has been shown to inhibit the proliferation of a variety of tumor cells. Epidemiological studies have shown that drinking green tea can reduce the incidence of nasopharyngeal carcinoma (NPC), yet the underlying mechanism is not well understood. In this study, the inhibitory effect of EGCG was tested on a set of Epstein Barr virus-negative and -positive NPC cell lines. Treatment with EGCG inhibited the proliferation of NPC cells but did not affect the growth of a non-malignant nasopharyngeal cell line, NP460hTert. Moreover, EGCG treated cells had reduced migration and invasive properties. The expression of the cell adhesion molecules E-cadherin and β-catenin was found to be up-regulated by EGCG treatment, while the down-regulation of matrix metalloproteinases (MMP)-2 and MMP-9 were found to be mediated by suppression of extracellular signal-regulated kinase (ERK) phosphorylation and AP-1 and Sp1 transactivation. Spheroid formation by NPC cells in suspension was significantly inhibited by EGCG. Oral administration of EGCG was capable of suppressing tumor growth in xenografted mice bearing NPC tumors. Treatment with EGCG was found to elevate the expression of p53 and p21, and eventually led to apoptosis of NPC cells via caspase 3 activation. The nuclear translocation of NF-κB and β-catenin was also suppressed by EGCG treatment. These results indicate that EGCG can inhibit the proliferation and invasiveness, and induce apoptosis, of NPC cells, making it a promising agent for chemoprevention or adjuvant therapy of NPC.

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This paper aims to explore the educative power of an experienced mathematics teacher educator-researcher (MTE-R) who displayed his insights and strategies in teacher professional development (TPD) programs. To this end, we propose a framework by first conceptualizing educative power based on three constructs-communication, reasoning, and connection-and then we extend the conceptualization with another two dimensions: the reciprocal facilitator-learner relationships involving educators, teachers, and students, as well as a bridge between research and practice. Based on both self-study and case-study approaches, we further elaborate features specific to the MTE-R's educative power which includes communication using an approach of creating educative phenomenology, reasoning by mapping teachers' ideas onto emergent models to solve problems in educative challenges, and connection between research and practice by coordination. In particular, the core of the educative power that supported the MTE-R to initiate at-the-moment actions was his insights into the essence of mathematics, and the learning of students and teachers. We believe that the conceptual framework in this study offers a powerful tool that could guide the analyses of educative power, especially for those studies related to the initiation of at-the-moment actions and the implementation of TPD programs.