Polyphenol-mediated inhibition of AP-1 transactivating activity may slow cancer growth by impeding angiogenesis and tumor invasiveness.

Certain polyphenols, capable of activating transcription via antioxidant response elements, potently induce Fra-1/Fra-2, thereby antagonizing the transactivating activity of AP-1 complexes. Since AP-1 is crucial to the induction of matrix proteases required for angiogenesis and tumor invasion, it is reasonable to suspect that adequate intakes of appropriate polyphenols would have utility in cancer therapy. Indeed, green tea polyphenols have reduced tumor growth rate and/or metastatic capacity in several animal studies. Additional measures for down-regulating AP-1 activity may include fish oil, heparin, and the drug LY290181. Down-regulation of AP-1 activity as a general therapeutic strategy merits further consideration.