Effect on Green Tea Polyphenols on Breast Cancer Signaling.
Abstract
Polyphenolic compounds in green tea have been implicated in the prevention of cancer, but their effects on cell signalling pathways are unknown. The current work was directed towards defining how such compounds inhibit cell proliferation and whether they inhibit oncogenic c-neu induced breast cancers in mice. Using the EGF dependent growth of MCF1OA epithelial cells as a model, we found that the major polyphenol in green tea, EGCG, inhibited progression through the late Gi cell cycle restriction point, but did not affect early steps in receptor tyrosine kinase signalling. Rather, EGCG sustained the EGF-dependent expression of the p21CIPl inhibitor of cyclin-dependent kinases and impaired phosphorylation of the retino- blastoma protein, pRB. This finding defines a novel way in which chemopreventive agents such as EGCG may inhibit mitogenic signals. In vivo studies failed to detect an inhibitory effect of green tea or tea polyphenols on c-neu induced mammary tumorigenesis in mice, suggesting that c-neu signals in a way that resists the effects of such compounds.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1999
- Accession Number
- ADA367380
Entities
People
- David E. Cobrinik
Organizations
- Columbia University