पृष्ठ 1 से 2505 परिणाम
OBJECTIVE
In 1988, we first reported the complete chemical structure of a new type of phorbol ester, abbreviated to DHPB, found in seed oil of Jatropha curcas L. (Saboodam in Thai) and its tumor-promoting activity on mouse skin. Although this seed oil contains toxic phorbol ester, it was planned to
It has been hypothesized that tumor growth is dependent on the concomitant growth of its vascular supply, and thus agents that stimulate angiogenesis may help support tumor growth. Phorbol esters are potent tumor promoters that induce a variety of biochemical effects in cells, including activation
The tumour-promoting agents 12-0-tetradecanoylphorbol-13-acetate (TPA) and phorbol-12, 13-dibutyrate (PDB) I are potent mitogens for human peripheral blood lymphocytes. In contrast, the non-cocarcinogenic substance phorbol lacks lymphocyte-activating properties. Non-toxic levels of retinoic acid
4a alpha-Phorbol-9,9a-didecanoate, 4a alpha-phorbol-9-myristate-9a-acetate, and phorbol-9-myristate-9a-acetate-3-aldehyde were tested for skin tumor-promoting activity by using 7,12-dimethylbenz(a)anthracene as the initiating agent. There were 30 female ICR/Ha mice/group, and tests were continued
We previously showed that phorbol esters are cytotoxic to human thyroid epithelial cells expressing a mutant RAS oncogene. Here we explore the generality of this finding using cells derived from pancreatic cancer, which, like thyroid, shows a high frequency of RAS mutation, but is a much greater
Cocultures were established of mouse epidermal cells (HEL/37) and mouse fibroblast cells (PG-19) deficient in the enzyme hypoxanthine-guanine phosphoribosyltransferase. Metabolic cooperation between the cocultured cells was detected as labeling of PG-19 cells on incubation of cocultures with
Treatment of bovine lymphocytes with 12-O-tetradecanoyl-phorbol-13-acetate (TPA) (10(-8) M) for as little as 5 min significantly alters the ability of membrane-particulate fractions to phosphorylate proteins using in situ protein kinases and exogenous [gamma-32P]ATP. After 20 min of treatment, the
The pathways of oxidant generation in mouse epidermis were investigated by 32P-postlabeling analysis of diastereomeric DNA adducts derived from oxidation of (7S,8S)-dihydroxy-7,8-dihydrobenzo(a)pyrene ((+)-BP-7,8-diol). The pattern of deoxynucleoside-3'-5'-bis-phosphate adducts in epidermal
Phorbolol myristate acetate, a metabolite of the tumor promotor phorbol muristate acetate in mouse skin, has one-fiftieth the potency of the parent molecule for the induction of cell division in stationary cultures of BALB/c-3T3 mouse embryo cells. Similarly, in a mixed cell culture assay devised
The tumor promoter phorbol-12-myristate-13-acetate (PMA) causes an increase in pol(ADP)-ribosylation in mouse and human fibroblasts via the intermediate formation of active oxygen. In contrast to poly(ADP)-ribosylation induced by the methylating agent N-methyl-N'-nitro-N-nitrosoguanidine, de novo
Tumor promoting phorbol esters are potent inhibitors of the chondrogenic differentiation of limb mesenchymal cells, but the mechanism by which these agents elicit their antichondrogenic effect is unknown. Here we report that limb mesenchymal cells inhibited from undergoing chondrogenesis by a tumor
Phorbol and eight of its derivatives were investigated for their ability to stimulate the synthesis of the enzyme plasminogen activator in cultured chick embryo fibroblasts and to aggregate human blood platelets and have been assayed for tumor, promoting and skin, irritant activities. Over a range
The effects of the protein kinase C (PKC) activators, phorbol ester 12-O-tetradecanoyl-13-phorbol acetate (TPA) and the marine natural product, bryostatin 1, on the growth and morphology of human breast cancer cell lines were examined. TPA (1 to 100 nM) inhibited growth of four of six cell lines by
Nucleoside transport systems and their regulation in human B-lymphocytes have been characterized using the cell lines Raji and Bare lymphoma syndrome-1 (BLS-1) as experimental models. These cells express at least three different nucleoside transport systems as follows: a
Prostratin and 12-deoxyphorbol 13-phenylacetate (dPP) form a new class of protein kinase C activators of unique biological activity. Although they bind to and activate protein kinase C, in mouse skin they either fail to induce typical phorbol ester (PMA) effects (e.g., hyperplasia) or induce only