碩士 國立中興大學 生命科學系所 98 It has been reported that green tea polyphenol (e.g. (-)-epigallocatechin-3-gallate, EGCg）can inhibit human MCF-7 breast cancer cell growth via the signal transduction pathways to modify the activity of fatty acid synthesis. In addition, EGCg has been shown to cause inhibition of tumor cell growth by altering the lipid compositions on cell membranes such as to induce the lipid raft associated with membrane receptors including human estrogen receptor （HER）and epidermal growth factor receptor（EGFR）in many cancer cells. The main goal of this study was to investigate whether EGCg can inhibit human MCF-7 breast cancer cell proliferation via the membrane-evoked signaling pathway to modulate cytoplasmic Ca2+ homeostasis. Using the MTT assay, EGCg was found to attenuate mitochondria-dependent cell viability of MCF-7 cells. Analyses by using western blot, quantitative real time PCR、and immune-cellular-fluorescence microscopy revealed the chemo-protection of EGCg on inhibition of MCF-7 breast cancer