DNA-protektives Potential von Polyphenolen in humanen Schleimhautzellkulturen

Abstract

The concept of field cancerization in the head and neck offers an excellent basis for chemopreventive interventions. Within the last few years, polyphenols, the most abundant phytochemicals in our diet, have been identified as interesting chemopreventive agents based on their multiple actions. This study was designed to add more experimental data regarding the chemopreventive features of epigallocatechin gallate (EGCG) and tannin (TA) in cultures of fresh biopsied tissue to epidemiologic studies and animal and cell line experiments. Miniorgan cultures (MOC) were produced from oropharyngeal mucosa-cubes about 1 mm(3), epithelialized and with their tissue structure preserved. The MOC were incubated with EGCG (0.1 and 5 microM) and TA (1 and 5 microM) for 30 min on three consecutive days. On the 3rd day, DNA damage was introduced with metabolically activated tobacco carcinogen benzo[a]pyren-7,8-dihydrodiol-9,10-epoxid (BPDE) [9 microM] for 60 min. The resulting DNA damage was measured with alkaline single-cell microgel electrophoresis (comet assay) and quantified using the olive tail moment (OTM). By incubating MOC with the polyphenols, the DNA damage caused by BPDE was significantly decreased at all concentrations. To our knowledge, this is the first test using cell cultures produced from fresh biopsies that demonstrates ECGC and TA as promising chemopreventive agents and confirms nutritional studies.