Cancer biology and hormesis: comments on Calabrese (2005).
Large numbers of chemicals of a variety of types exhibit apparent hormetic effects on cultured human cancer cells, causing stimulation of cell growth or related changes at low doses, followed by inhibition at higher doses. Many of the studies listed are not fully convincing, due to lack of appropriate controls or sufficient number of doses. However, the proposed hormetic response seems firmly established in a subset of these experiments. Significance with regard to in vivo cancer growth has not been pursued and must be a priority for the future. For several examples where in vivo titers are known, such as, resveratrol, suramin, and tamoxifen, comparison of the dose and concentration ranges confirms that hormesis could be an issue in vivo. Further investigations are warranted, especially for therapeutic drugs, phytochemicals, and environmental toxicants.
Anderson
Lucy M
LM
Laboratory of Comparative Carcinogenesis, National Cancer Institute at Frederick, Ft Detrick, Maryland 21702, USA. Andersol@ncifcrf.gov
D000222:Adaptation, Physiological / Q000187:drug effects* / Q000502:physiology; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002273:Carcinogens / Q000633:toxicity*; D002455:Cell Division / Q000187:drug effects*; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D006801:Humans; D019055:No-Observed-Adverse-Effect Level; D000077185:Resveratrol; D018570:Risk Assessment; D013267:Stilbenes / Q000494:pharmacology; D013498:Suramin / Q000494:pharmacology; D013629:Tamoxifen / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D000970:Antineoplastic Agents; D002273:Carcinogens; D013267:Stilbenes; D013629:Tamoxifen; D013498:Suramin; D000077185:Resveratrol