Differential cellular responses to epigallocatechin-3-O-gallate of human dermal fibroblasts vs. human fibrosarcoma cells

Green tea polyphenols (GTPs) have shown cancer chemopreventive andchemotherapeutic effects in many animal tumor bioassays, cell culture systems, andepidemiological studies. These anti-cancer activities of GTPs are believed to be mostlymediated by epigallocatechin-3-O-gallate (EGCG), the predominant component of greentea. Many researchers have reported that EGCG or its derivatives results in cell cyclearrest and apoptosis of several cancer cells, but not of normal cells. However, themechanism of these differential responses to EGCG in cancer cells vs. normal cells is notfully elucidated yet. This chapter concentrates on the cell cycle-related molecular targetsfor the differential regulation of cell growth, morphology, apoptosis and phosphorylatednuclear factor-κB (pNF-κB) expression by EGCG in human dermal fibroblasts (HDFs)vs. human fibrosarcoma (HT-1080) cells. The first part deals with the differential effects of EGCG on cell growth, morphology and cell cycle progression of HDFs vs. HT-1080cells. The second is about the differential regulatory effects of EGCG on apoptosis andpNF-κB expression of HDFs vs. HT-1080 cells. The third deals with the differentialcellular uptake patterns of EGCG conjugated with FITC in HDFs vs. HT-1080 cells. Thelast is about the reversible regulatory effects of EGCG on the expression of cell cyclerelatedgenes and proteins in HDFs. Taking all things into account, the differentialregulatory activities of EGCG in normal cells vs. cancer cells may be exploited to crafttarget-specific strategies, such as the cytoprotection of normal cells and chemopreventionof cancer cells.