Signal transduction pathways: targets for chemoprevention of skin cancer.

Chemoprevention can be defined as the use of substances to interfere with the process of cancer development. Although substantial progress has been made in elucidating the basis of carcinogenesis, further advances are needed to identify molecular and cellular targets for effective use of chemopreventive agents. Hundreds of compounds have been identified as potential chemopreventive agents. However, the safety and efficacy of each substance must be thoroughly investigated. Carcinogenesis is a multistage process in which numerous genes are affected. Many of these genes regulate important cellular functions, so they are prime targets for chemopreventive agents. A major focus of our work has been the elucidation of mechanism(s) explaining the anticancer actions attributed to several chemopreventive compounds, especially 'natural compounds' that are considered safe because they are present in commonly consumed foods and beverages. Of particular interest are selected drugs (eg aspirin) and certain dietary factors (eg green and black tea, resveratrol) and their influence on cell-signalling events coinciding with skin cancer promotion. This overview describes recent work from our laboratory and others focusing on molecular mechanisms of selected chemopreventive compounds in growth-related signal transduction pathways and skin cancer.