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Rel/NF-kappaB transcription factors are implicated in the control of cell proliferation, apoptosis and transformation. The key to NF-kappaB regulation is the inhibitory IkappaB proteins. During response to diverse stimuli, IkappaBs are rapidly phosphorylated by IkappaB kinases (IKKs), ubiquitinated and undergo degradation. We have investigated the(More)
Free radical generating peroxides are potent skin irritants. After a single topical application of either 10, 20, or 40 mg of lauroyl peroxides or benzoyl peroxide on the dorsal skin of Sencar mice, the epidermal thickness increased markedly. No major inflammatory or vascular alterations were noted. On the other hand, 15 or 30% hydrogen peroxide produced an(More)
We tested the ability of avicins, a family of triterpenoid saponins obtained from Acacia victoriae (Bentham) (Leguminosae: Mimosoideae), to inhibit chemically induced mouse skin carcinogenesis. Varying doses of avicins were applied to shaved dorsal skin of SENCAR mice 15 min before application of 100 nmol of 7,12-dimethylbenz[a]anthracene (DMBA) twice a(More)
The SENCAR stock of mice has proved to be a useful model in dissecting out the multistage nature as well as the critical mechanisms involved in skin tumorigenesis. This outbred stock was selectively bred to be susceptible to initiation with 7,12-dimethylbenz[a]anthracene (DMBA) and promotion with 12-O-tetradecanoylphorbol-13-acetate (TPA). In order to(More)
The tumor promoter 12-O-tetradecanoylphorbol-13-acetate and the antileukemic agent mezerein are diterpene esters of plant origin with certain structural similarities. Both compounds, when applied topically to mouse skin, were equipotent on a molar basis in inducing hyperplasia, inflammation, and ornithine decarboxylase activity, as well as in reducing(More)
The effects of phorbol ester tumor promoters and related compounds on superoxide dismutase (SOD) and catalase were examined. The treatment of adult mouse skin with 2 micrograms 12-O-tetradecanoylphorbol-13-acetate (TPA) resulted in a sustained decrease in the basal levels of both SOD and catalase activities in the epidermis. A decline in SOD activity(More)
In order to define factors which determine susceptibility to chemical carcinogenesis, mice sensitive (SENCAR) and resistant (BALB/c) to epidermal carcinogenesis were studied under several treatment conditions for sensitivity to initiation by 7,12-dimethylbenz(a)anthracene or N-methyl-N'-nitro-N-nitrosoguanidine and promotion by(More)
We report a systematic histopathologic study of papillomas at different times during promotion, correlating the results with those from cytogenetic analysis of the same tumors. Papillomas were induced in SENCAR mice by two-stage carcinogenesis (7,12-dimethylbenz[a]anthracene and phorbol 12-myristate 13-acetate). Individual tumors were randomly sampled at(More)
Varying doses of ellipticine (EL), flavone (FL), or 7,8-benzoflavone (78BF) were applied to mouse skin 5 min before an initiating dose of 10 nmol 7,12-dimethylbenz[a]anthracene (DMBA), 47.5 nmol 7,14-dimethylbenzo[a,h]anthracene (DDBA), or 200 nmol dibenzo[a,h]anthracene (DBA) and the development of skin tumors in the mice then promoted by topical(More)
To elucidate the role of keratin modification in tumor promotion, we investigated the keratin polypeptide patterns of mouse epidermis, papillomas, and carcinomas throughout an initiation-promotion experiment. The epidermal keratin modifications induced by repetitive 12-O-tetradecanoylphorbol-13-acetate treatments in both initiated and noninitiated mouse(More)