Biomaterial Database

Loss of mouse epidermal protein kinase C isozyme activities following treatment with phorbol ester and non-phorbol ester tumor promoters. 1994

X J Wang, and B S Warren, and T Rupp, and L M Beltrán, and J DiGiovanni

Department of Carcinogenesis, University of Texas MD, Anderson Cancer Center, Smithville 78957.

The present study has examined changes in activities and levels of four protein kinase C (PKC) isozymes (PKC alpha, PKC beta, PKC gamma and PKC delta) detectable in mouse epidermal preparations following both single and multiple treatments with 12-O-tetradecanoylphorbol-13-acetate (TPA). In addition, PKC epsilon and PKC eta protein levels were monitored by immunoblotting following TPA application. Finally, PKC isozyme activity profiles were also examined in epidermal preparations from mice treated with single applications of two non-phorbol ester tumor promoters: chrysarobin (CHRY) and okadaic acid (OA). Fifteen minutes following topical treatment with a tumor promoting dose of TPA (3.4 nmol), the activities of PKC beta and PKC gamma decreased in the epidermal cytosol to 30% and 50% of control values, respectively, while these activities were increased in the epidermal particulate fraction by approximately 50%. PKC delta activity, found predominantly in the particulate fraction of control epidermis, was greatly diminished in both subcellular fractions at 15 min while PKC alpha activity was translocated approximately 20% from cytosol to particulate fraction. Significant reductions in all four detectable PKC isozyme activities in both particulate and cytosol fractions were observed 48 h after a single treatment with TPA, although particulate PKC alpha activity appeared to be less affected at this point in time compared to the other PKC isozymes. Immunoblotting analyses of PKC isozyme protein levels after TPA treatment followed the changes in activity for cytosolic PKC alpha, PKC beta and PKC gamma. However, particulate PKC delta and PKC epsilon protein levels remained relatively unchanged while particulate PKC eta protein levels were significantly down-regulated after a single TPA treatment. Multiple topical treatments (twice-weekly for 2 weeks) with TPA produced a pattern of loss followed by only partial recovery of total PKC activity. Furthermore, all four PKC isozyme activities examined by hydroxylapatite (HA) chromatography were significantly reduced, including PKC alpha, after four applications of TPA. Cytosolic PKC alpha, PKC beta and PKC gamma protein levels as determined by immunoblotting again followed the activity profiles; particulate PKC eta protein levels were significantly reduced, whereas particulate PKC delta and PKC epsilon levels again appeared relatively unchanged. Fifteen minutes after topical application of 220 nmol CHRY, an approximately 25% decrease in particulate associated with PKC alpha activity was observed while particulate activities associated with PKC beta, PKC gamma and PKC delta were unaffected by CHRY at this time point.(ABSTRACT TRUNCATED AT 400 WORDS)

UI	MeSH Term	Description	Entries
D007527	Isoenzymes	Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.	Alloenzyme,Allozyme,Isoenzyme,Isozyme,Isozymes,Alloenzymes,Allozymes
D008565	Membrane Proteins	Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.	Cell Membrane Protein,Cell Membrane Proteins,Cell Surface Protein,Cell Surface Proteins,Integral Membrane Proteins,Membrane-Associated Protein,Surface Protein,Surface Proteins,Integral Membrane Protein,Membrane Protein,Membrane-Associated Proteins,Membrane Associated Protein,Membrane Associated Proteins,Membrane Protein, Cell,Membrane Protein, Integral,Membrane Proteins, Integral,Protein, Cell Membrane,Protein, Cell Surface,Protein, Integral Membrane,Protein, Membrane,Protein, Membrane-Associated,Protein, Surface,Proteins, Cell Membrane,Proteins, Cell Surface,Proteins, Integral Membrane,Proteins, Membrane,Proteins, Membrane-Associated,Proteins, Surface,Surface Protein, Cell
D011493	Protein Kinase C	An serine-threonine protein kinase that requires the presence of physiological concentrations of CALCIUM and membrane PHOSPHOLIPIDS. The additional presence of DIACYLGLYCEROLS markedly increases its sensitivity to both calcium and phospholipids. The sensitivity of the enzyme can also be increased by PHORBOL ESTERS and it is believed that protein kinase C is the receptor protein of tumor-promoting phorbol esters.	Calcium Phospholipid-Dependent Protein Kinase,Calcium-Activated Phospholipid-Dependent Kinase,PKC Serine-Threonine Kinase,Phospholipid-Sensitive Calcium-Dependent Protein Kinase,Protein Kinase M,Calcium Activated Phospholipid Dependent Kinase,Calcium Phospholipid Dependent Protein Kinase,PKC Serine Threonine Kinase,Phospholipid Sensitive Calcium Dependent Protein Kinase,Phospholipid-Dependent Kinase, Calcium-Activated,Serine-Threonine Kinase, PKC
D002273	Carcinogens	Substances that increase the risk of NEOPLASMS in humans or animals. Both genotoxic chemicals, which affect DNA directly, and nongenotoxic chemicals, which induce neoplasms by other mechanism, are included.	Carcinogen,Oncogen,Oncogens,Tumor Initiator,Tumor Initiators,Tumor Promoter,Tumor Promoters,Initiator, Tumor,Initiators, Tumor,Promoter, Tumor,Promoters, Tumor
D003600	Cytosol	Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.	Cytosols
D004305	Dose-Response Relationship, Drug	The relationship between the dose of an administered drug and the response of the organism to the drug.	Dose Response Relationship, Drug,Dose-Response Relationships, Drug,Drug Dose-Response Relationship,Drug Dose-Response Relationships,Relationship, Drug Dose-Response,Relationships, Drug Dose-Response
D004790	Enzyme Induction	An increase in the rate of synthesis of an enzyme due to the presence of an inducer which acts to derepress the gene responsible for enzyme synthesis.	Induction, Enzyme
D004817	Epidermis	The external, nonvascular layer of the skin. It is made up, from within outward, of five layers of EPITHELIUM: (1) basal layer (stratum basale epidermidis); (2) spinous layer (stratum spinosum epidermidis); (3) granular layer (stratum granulosum epidermidis); (4) clear layer (stratum lucidum epidermidis); and (5) horny layer (stratum corneum epidermidis).
D004988	Ethers, Cyclic	Compounds of the general formula R-O-R arranged in a ring or crown formation.	Cyclic Ether,Cyclic Ethers,Ether, Cyclic
D005260	Female		Females