Abstract

Treatment of murine skin and cultures of murine epidermal or hepatoma cells with 12-0-tretradecanoylphorbol-13-acetate (TPA) reduces basal cytochrome P450-dependent monooxygenase activities, and suppresses the rise in the monooxygenase 7-ethoxyresorufin O-deethylase (7-ERD) that normally occurs after treatment with P450 inducers. TPA is a potent activator of protein kinase C (PKC). The overall hypothesis of the proposal is that PKC regulates the expression/activities of some P-450 species. This hypothesis will be examined by analyzing the effects of PKC inhibitors and PKC down regulation on the TPA-dependent suppression of 7-ERD induction in the aforementioned systems. PKC activators structurally unrelated to TPA, and analogs of TPA incapable of activating PKC will also be surveyed for their abilities to modulate 7-ERD (cytochrome CYPIA1) expression. Analyses of 7-ERD induction in cultured epidermal and hepatoma cells will also be made following reduction or elevation of cellular PKC activities by transfection of PKC antisense oligodeoxynucleotides or PKC cDNA expression vectors, respectively. Antibodies and cDNA probes to P-450IAl will be used to determine whether the TPA-mediated effects on 7-ERD activity reflect transcriptional or post-transcriptional regulation. If steady state RNA levels are affected by TPA, rates of IA1 transcription and IA1 mRNA half lifes will be determined. Relevance of PKC mediated suppression of IA1 induction to the processes of in vivo xenobiotic metabolism and chemical carcinogenesis will be assessed by analyses of epidermal DNA-adducts and the numbers of skin tumors that develop in an initiation-promotion protocol employing benzo[a]pyrene as the initiator. Lastly, the effects of TPA and other PKC activators on the inductions of P-450 cytochromes IA1, IA2, IIB1, IIB2, and IIE1 in rat liver will be determined to assess the generality of PKC as a regulator of P450 expression. These studies will characterize a new and novel mechanism for the regulation of the P-450 system, and may proyide a general explanation for the suppressive effects of a variety ot agents on the P-450 system.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA034469-11
Application #
2088687
Study Section
Metabolic Pathology Study Section (MEP)
Project Start
1983-09-01
Project End
1995-08-31
Budget Start
1994-09-01
Budget End
1995-08-31
Support Year
11
Fiscal Year
1994
Total Cost
Indirect Cost

  Institution

Name
Wayne State University
Department
Type
Organized Research Units
DUNS #
City
Detroit
State
MI
Country
United States
Zip Code
48202

  Publications

Joiakim, Aby; Mathieu, Patricia A; Palermo, Christine et al. (2003) The Jun N-terminal kinase inhibitor SP600125 is a ligand and antagonist of the aryl hydrocarbon receptor. Drug Metab Dispos 31:1279-82
Guo, Meng; Mathieu, Patricia A; Linebaugh, Bruce et al. (2002) Phorbol ester activation of a proteolytic cascade capable of activating latent transforming growth factor-betaL a process initiated by the exocytosis of cathepsin B. J Biol Chem 277:14829-37
Guo, M; Joiakim, A; Dudley, D T et al. (2001) Suppression of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-mediated CYP1A1 and CYP1B1 induction by 12-O-tetradecanoylphorbol-13-acetate: role of transforming growth factor beta and mitogen-activated protein kinases. Biochem Pharmacol 62:1449-57
Caruso, J A; Reiners Jr, J J; Emond, J et al. (2001) Genetic alteration of chromosome 8 is a common feature of human mammary epithelial cell lines transformed in vitro with benzo[a]pyrene. Mutat Res 473:85-99
Santini, R P; Myrand, S; Elferink, C et al. (2001) Regulation of Cyp1a1 induction by dioxin as a function of cell cycle phase. J Pharmacol Exp Ther 299:718-28
Guo, M; Joiakim, A; Reiners Jr, J J (2000) Suppression of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-mediated aryl hydrocarbon receptor transformation and CYP1A1 induction by the phosphatidylinositol 3-kinase inhibitor 2-(4-morpholinyl)-8-phenyl-4H-1- benzopyran-4-one (LY294002). Biochem Pharmacol 60:635-42
Guo, M; Reiners Jr, J J (2000) Phorbol ester-induced production of cytostatic factors by normal and oncogenic Ha-ras-transformed human breast cell lines. Carcinogenesis 21:1303-12
Reiners Jr, J J; Mathieu, P; Okafor, C et al. (2000) Depletion of cellular glutathione by conditions used for the passaging of adherent cultured cells. Toxicol Lett 115:153-63
Reiners Jr, J J; Clift, R E (1999) Aryl hydrocarbon receptor regulation of ceramide-induced apoptosis in murine hepatoma 1c1c7 cells. A function independent of aryl hydrocarbon receptor nuclear translocator. J Biol Chem 274:2502-10
Reiners Jr, J J; Clift, R; Mathieu, P (1999) Suppression of cell cycle progression by flavonoids: dependence on the aryl hydrocarbon receptor. Carcinogenesis 20:1561-6

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