The long-term goal of this project is to determine the role of protein kinase C (PKC) and the phospholipid-hydrolyzing enzymes in the mediation of growth regulatory effects of ethanol with a special focus on fetal alcohol syndrome (FAS) and the """"""""co-carcinogenic"""""""" effects of ethanol. The proposed work will initially determine the mechanisms by which ethanol stimulates both transient and prolonged hydrolysis of phosphatidylethanolamine (PtdEtn) by phospholipase D (PLD) and phospholipase C (PLC), respectively. Both effects require concomitant activation of PKC-epsilon (and perhaps PKC-delta by PKC activators, including phorbol 12-myristate-13-acetate (PMA), but PKC-epsilon regulates the PLD and PLC activities differently. With respect to the regulation of PLD (Aim 1), the proposed work will examine the possibility that potentiation of the stimulatory PMA effect by ethanol is due to the inhibition of p21/ras, a negative regulator of PLD. As an important tool to verify this mechanism, the effect of ethanol on the activity state of p21/ras will be determined by measuring binding of GTP to immunoprecipitated p21/ras. With respect to the regulation of PLC (Aim 2), a major task will be to determine whether PKC-epsilon potentiates the effect of ethanol per se, or PKC-epsilon stimulates the synthesis of fatty acid ethyl esters (FAEE), the possible ultimate regulator of PLC. This latter mechanism is possible because 1-chloro-2,4-dinitrobenzene (CDNB), an inhibitor of FAEE-synthase III, was found to inhibit the effect of ethanol on PLC-mediated PtdEtn hydrolysis. Various molecular species of FAEE will be synthesized to determine their possible effects on PLC activity. The work in Aim 3 will examine the role of PKC-epsilon, PKC-delta, and PLC in the mediation of inhibitory ethanol effect on nerve growth factor-induced neurite formation, a measure of differentiation, in PC12 neural cells. PKC-epsilon and PKC-delta will be overexpressed in PC12 neural cells to examine if they potentiate the inhibitory effect of ethanol on neurite formation. To probe the mediatory role of PLC, the effect of ethanol on neurite formation in control and PKC-overexpressing cells will be determined in the presence of CDNB. In the C3H/10T1/2 fibroblast system, a cellular model for carcinogenesis, ethanol potentiated the formation of transforming foci induced by a suboptimal concentration (0.25 microg/ml) of 7,12-dimethylbenz[a]anthracene. Work in Aim 4 will examine the role of PLC in the mediation of this apparent co-carcinogenic effect of ethanol (or FAEE), by using the inhibitor CDNB. The projected work will likely reveal that the effects of ethanol (or FAEE) on neural cell differentiation and carcinogenesis involve specific PKC isozymes as well as increased PtdEtn hydrolysis. This outcome could identify PtdEtn-specific PLC as a possible site of intervention to alleviate these effects of ethanol.

Agency
National Institute of Health (NIH)
Institute
National Institute on Alcohol Abuse and Alcoholism (NIAAA)
Type
Research Project (R01)
Project #
5R01AA009292-05
Application #
2732441
Study Section
Biochemistry, Physiology and Medicine Subcommittee (ALCB)
Project Start
1994-07-01
Project End
1999-06-30
Budget Start
1998-07-01
Budget End
1999-06-30
Support Year
5
Fiscal Year
1998
Total Cost
Indirect Cost
Name
University of Minnesota Twin Cities
Department
Miscellaneous
Type
Other Domestic Higher Education
DUNS #
168559177
City
Minneapolis
State
MN
Country
United States
Zip Code
55455
Crilly, K S; Benyhe, S; Kiss, Z (2000) Promitogenic effects of ethanol, methanol, and ethanolamine in insulin-treated fibroblasts. Biochem Pharmacol 60:1391-8
Deli, E; Kiss, Z (2000) Protein kinase C-stimulated formation of ethanolamine from phosphatidylethanolamine involves a protein phosphorylation mechanism: negative regulation by p21 Ras protein. Arch Biochem Biophys 377:171-7
Chung, T; Huang, J S; Mukherjee, J J et al. (2000) Expression of human choline kinase in NIH 3T3 fibroblasts increases the mitogenic potential of insulin and insulin-like growth factor I. Cell Signal 12:279-88
Huang, J S; She, Q B; Crilly, K S et al. (2000) Ethanol, Zn2+ and insulin interact as progression factors to enhance DNA synthesis synergistically in the presence of Ca2+ and other cell cycle initiators in fibroblasts. Biochem J 346 Pt 1:241-7
Kiss, Z (1999) Anandamide stimulates phospholipase D activity in PC12 cells but not in NIH 3T3 fibroblasts. FEBS Lett 447:209-12
Kiss, Z (1999) Regulation of mitogenesis by water-soluble phospholipid intermediates. Cell Signal 11:149-57
Huang, J S; Mukherjee, J J; Chung, T et al. (1999) Extracellular calcium stimulates DNA synthesis in synergism with zinc, insulin and insulin-like growth factor I in fibroblasts. Eur J Biochem 266:943-51
Mukherjee, J J; Huang, J S; Getman, C et al. (1999) Bombesin promotes synergistic stimulation of DNA synthesis by ethanol and insulin in fibroblasts. Arch Biochem Biophys 362:183-9
Huang, J S; Mukherjee, J J; Kiss, Z (1999) Ethanol potentiates the mitogenic effects of sphingosine 1-phosphate by a zinc- and calcium-dependent mechanism in fibroblasts. Arch Biochem Biophys 366:131-8
She, Q B; Huang, J S; Mukherjee, J J et al. (1999) The possible mechanism of synergistic effects of ethanol, zinc and insulin on DNA synthesis in NIH 3T3 fibroblasts. FEBS Lett 460:199-202

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