Growth Stimulation and Tumor Promotion in Skin

Molecular Mechanisms of Mouse Skin Tumor Promotion

Multiple molecular mechanisms are involved in the promotion of skin carcinogenesis. Induction of sustained proliferation and epidermal hyperplasia by direct activation of mitotic signaling pathways or indirectly in response to chronic wounding and/or inflammation, or due to a block in terminal differentiation or resistance to apoptosis is necessary to allow clonal expansion of initiated cells w...

Epidermal growth control mechanisms, hyperplasia, and tumor promotion in the skin.

Metformin inhibits skin tumor promotion in overweight and obese mice.

In the present study, the ability of metformin to inhibit skin tumor promotion by 12-O-tetradecanoylphorbol-13-acetate (TPA) was analyzed in mice maintained on either an overweight control diet or an obesity-inducing diet. Rapamycin was included for comparison, and a combination of metformin and rapamycin was also evaluated. Metformin (given in the drinking water) and rapamycin (given topically...

Dose and frequency effect in mouse skin tumor promotion.

In order to study the influence of both dose and application frequency of tumor-promoting agents on tumor development, we conducted a large-scale mouse skin two-stage carcinogenesis experiment. The back skins of 1110 CD-1 mice were painted once with 50 micrograms benzo(a)pyrene. These mice were divided into 24 groups according to subsequent schedules of 12-O-tetradecanoylphorbol-13-acetate (TPA...

Inhibition of multistage tumor promotion in mouse skin by diethyldithiocarbamate.

Diethyldithiocarbamate (DDTC) injected i.p. inhibits remarkably and in a dose-dependent manner 12-O-tetradecanoylphorbol-13-acetate (TPA)-decreased glutathione (GSH) peroxidase and TPA-induced ornithine decarboxylase (ODC) activities in mouse epidermis in vivo. DDTC is more potent in inhibiting these effects of TPA than 16 other antioxidants, free radical scavengers, thiol-containing compounds,...