Chemical-inducible promoters

After intramuscular injection, nickel sulphate failed to induce tumours in rats [460], However, orally administered nickel chloride had an apparent promoting effect on chemically-induced renal tumorigenesis [461]. 

Chemical-Inducible and Developmental Promoters FOR Temporal or Spatial Gene Expression... 

Klurfeld, D.M., Weber, M.M. Kritchevsky, D. (1987) Inhibition of chemically induced mammary and colon tumor promotion by caloric restriction in rats fed increased dietary fat. Cancer Res., 47, 2759-2762... 

Gibberellins can induce flowering in many plant species, such as carrots, that require low temperatures to initiate this process. The ability of a chemical to promote flowering is... 

Our laboratory has completed a series of studies designed to evaluate the simultaneous effects of dietary protein and fat on 7,12-dimethylbenz(a)anthracene (DMBA)-induced breast cancer in rats. Sprague-Dawley female rats were assigned to nine diets in a 3 x 3 factorial arrangement with protein (casein) at 8, 16, and 32% of kcals and fat (corn oil) at 12, 24, and 48% of kcals. As fat content was increased, all nutrients other than carbohydrate were adjusted to remain constant with respect to calories. Forty rats were assigned to each diet for each of three experiments (Figure 1) to examine initiation, promotion, and the combined phases of chemically-induced carcinogenesis. 

Both p-carotene and vitamin A can inhibit growth in a large range of human cancer cell lines (Krinsky, 1993 Niles, 2000). Several animal studies have shown that vitamin A deficiency promotes the development of spontaneous and chemically-induced tumors, whereas dietary supplementation with vitamin A can prevent chemically-induced tumor development (Niles, 2000). Likewise, p-carotene protects against tumor development in animal models (Krinsky, 1993 Cooper, 2004 Russell, 2004). Nevertheless, P-carotene is preferred for human studies because blood and tissue levels increase in proportion to dietary intake, whereas vitamin A level does not increase in a linear manner because of homeostatic regulation high levels of vitamin A are toxic (Cooper, 2004). 

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