mezerein/neoplasms

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

Previous studies in our laboratory have shown that promotion of two-stage skin carcinogenesis in the SENCAR mouse model was inhibited in mice fed energy-restricted/low-fat diets, and elevated in mice fed high-fat diets. Studies reported here describe the influence of dietary energy restriction from

Mezerein, the most active antitumor compound isolated from the daphne species of plants, has a structural similarity to phorbol myristate acetate (PMA), the major active compound isolated from croton oil. PMA is known to have tumor promoting activity and is a potent inflammatory agent. Mezerein has

Cepharanthine, isolated from Stephania cepharantha, is one of the bisbenzylisoquinoline-type alkaloids. We have found that it inhibits tumor promotion after topical application in two-stage carcinogenesis in mouse skin. Epidermal ornithine decarboxylase activities inhibited by topical application of

The combination of recombinant human fibroblast interferon (INF-delta) and the antileukemic compound mezerein (MEZ) results in a synergistic suppression in the growth of human melanoma cells and a concomitant increase in melanin synthesis. In the present study we have further analyzed this

m-Chloroperoxybenzoic acid (CPBA),which induces ornithine decarboxylase activity as much as 12-O-tetradecanoylphorbol-13-acetate (TPA), was tested for its ability to induce DNA synthesis, hydroperoxide (HPx) production, and tumor promotion in mouse epidermis in vivo. After an early inhibition, CPBA

More than one application of the potent tumor-promoting agent, 12-O-tetradecanoylphorbol-13-acetate (TPA), to mouse skin at intervals of more than 48 h led to a larger induction of ornithine decarboxylase (EC 4.1.1.17; ODC) than did a single application. In contrast, at intervals of less than 24 h,

Tumor promoters such as phorbol 12-tetradecanoate 13-acetate (TPA), mezerein, teleocidin, aplysiatoxin, and benzoyl peroxide, although structurally unrelated, induce similar, profound changes in morphology in differentiated epithelial Madin-Darby canine kidney (MDCK) cell colonies. The alteration is

Topical application of tumor-promoting agents to the dorsal skin of female SENCAR mice on a twice-weekly basis resulted in a reduction in density per unit area of bone marrow-derived Thy-1+ dendritic cells. Activity was observed for well-established tumor-promoting doses of promoting agents of

Human peripheral blood monocytes were cultured and exposed to plant diterpenes, indole alkaloids and polyacetates with various degrees of tumor-promoting activity. The effect of the above-mentioned encounter on monocyte function was examined, as expressed by H2O2 production and lysis of dog

Incubation of rat hepatocytes with active phorbol esters and mezerein provoked a decrease in glycogen synthase activity. After the incubation of [3 2 P] phosphate-labeled cells with these tumor promoters, an increase in the amount of 3 2 P bound to the immunoprecipitated enzyme was observed. The

Glucocorticoids (anti-inflammatory steroids) are very potent inhibitors of mouse skin tumor promotion induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). This report describes a high-affinity, limited-capacity binding component which specifically interacts with glucocorticoids and which is

Using an 18 week two-stage protocol we have compared the tumour-promoting properties of a range of phorbol and daphnane esters on female CD-1 mice. The induction of epidermal hyperplasia in this mouse strain by these compounds has also been assessed by comparison with the standard phorbol ester,

The addition of the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) to defined growth medium stimulated an intense neurite outgrowth from chick sensory ganglia explants. The development of radial neurites was concentration dependent. At low concentrations of TPA (1.6 to 16 nM), neurites

The effect of phorbol ester tumour promoters on the release of superoxide anion radicals .O2- by human peripheral leukocytes and the role of such radicals in tumour promotion of mouse skin was studied. No significant difference was found between complete [12-O-tetradecanoylphorbol-13-acetate (TPA)]