1
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Chang SN, Dey DK, Oh ST, Kong WH, Cho KH, Al-Olayan EM, Hwang BS, Kang SC, Park JG. Phorbol 12-Myristate 13-Acetate Induced Toxicity Study and the Role of Tangeretin in Abrogating HIF-1α-NF-κB Crosstalk In Vitro and In Vivo. Int J Mol Sci 2020; 21:E9261. [PMID: 33291656 PMCID: PMC7729754 DOI: 10.3390/ijms21239261] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 11/26/2020] [Accepted: 12/01/2020] [Indexed: 11/16/2022] Open
Abstract
Phorbol 12-myristate 13-acetate (PMA) is a potent tumor promoter and highly inflammatory in nature. Here, we investigated the toxic effects of PMA on different model system. PMA (10 μg) caused chromosomal aberrations on the Allium cepa root tip and induced mitotic dysfunction. Similarly, PMA caused embryonic and larval deformities and a plummeted survivability rate on zebrafish embryo in a dose-dependent manner. Persistently, PMA treatment on immortalized human keratinocyte human keratinocyte (HaCaT) cells caused massive inflammatory rush at 4 h and a drop in cell survivability at 24 h. Concomitantly, we replicated a cutaneous inflammation similar to human psoriasis induced by PMA. Herein, we used tangeretin (TAN), as an antagonist to counteract the inflammatory response. Results from an in vivo experiment indicated that TAN (10 and 30 mg/kg) significantly inhibited PMA stimulated epidermal hyperplasia and intra-epidermal neutrophilic abscesses. In addition, its treatment effectively neutralized PMA induced elevated reactive oxygen species (ROS) generation on in vitro and in vivo systems, promoting antioxidant response. The association of hypoxia-inducible factor 1-alpha (HIF-1α)-nuclear factor kappa-light-chain-enhancer of activated b cells (NF-κB) crosstalk triggered by PMA enhanced PKCα-ERK1/2-NF-κB pathway; its activation was also significantly counteracted after TAN treatment. Conclusively, we demonstrated TAN inhibited the nuclear translocation of HIF-1α and NF-κB p65. Collectively, TAN treatment ameliorated PMA incited malignant inflammatory response by remodeling the cutaneous microenvironment.
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Affiliation(s)
- Sukkum Ngullie Chang
- Department of Biotechnology, Daegu University, Gyeongsan 38453, Korea; (S.N.C.); (D.K.D.)
- Advanced Bio Convergence Center, Pohang Technopark Foundation, Pohang 37668, Gyeongbuk, Korea; (S.T.O.); (W.H.K.)
| | - Debasish Kumar Dey
- Department of Biotechnology, Daegu University, Gyeongsan 38453, Korea; (S.N.C.); (D.K.D.)
| | - Seong Taek Oh
- Advanced Bio Convergence Center, Pohang Technopark Foundation, Pohang 37668, Gyeongbuk, Korea; (S.T.O.); (W.H.K.)
- Okinawa Research Center Co. Ltd., 13-33, Suzaki, Uruma-si, Okinawa Ken 904-2234, Japan
| | - Won Ho Kong
- Advanced Bio Convergence Center, Pohang Technopark Foundation, Pohang 37668, Gyeongbuk, Korea; (S.T.O.); (W.H.K.)
| | - Kiu Hyung Cho
- Research Group, Gyeongbuk Institute for Bio Industry (GIB), Andong 36728, Korea;
| | - Ebtesam M. Al-Olayan
- Department of Zoology, Faculty of Science, King Saud University, Riyadh 11451, Saudi Arabia;
| | - Buyng Su Hwang
- Nakdonggang National Institute of Biological Resources, Sangju 37242, Korea;
| | - Sun Chul Kang
- Department of Biotechnology, Daegu University, Gyeongsan 38453, Korea; (S.N.C.); (D.K.D.)
| | - Jae Gyu Park
- Advanced Bio Convergence Center, Pohang Technopark Foundation, Pohang 37668, Gyeongbuk, Korea; (S.T.O.); (W.H.K.)
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2
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Grosvenor SNJ, McLean S, Reynolds WF, Tinto WF. Two Phorbol Esters from Sapium Hippomane. Nat Prod Commun 2019. [DOI: 10.1177/1934578x0700200203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
A chemical study of the bark of Sapium hippomane (Euphorbiaceae), obtained in the parish of St. John, Barbados, led to the isolation of two new phorbol esters (1 and 2), in addition to the known compound 4-deoxyphorbol (3). Compounds 1 and 2 were C-4 epimers, with a tigliane-type skeleton possessing C5 esters at C-12 and C-13. Chromatographic methods were utilized to separate the compounds and their structures determined through interpretation of physical data.
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Affiliation(s)
- Sumieya N. J. Grosvenor
- Laboratory of Bioorganic Chemistry, Department of Biological & Chemical Sciences, University of the West Indies, Cave Hill Campus, Bridgetown, P.O. Box 64, Barbados, BB11000
| | - Stewart McLean
- Department of Chemistry, University of Toronto, Toronto, Ontario, M5S 3H6, Canada
| | - William F. Reynolds
- Department of Chemistry, University of Toronto, Toronto, Ontario, M5S 3H6, Canada
| | - Winston F. Tinto
- Laboratory of Bioorganic Chemistry, Department of Biological & Chemical Sciences, University of the West Indies, Cave Hill Campus, Bridgetown, P.O. Box 64, Barbados, BB11000
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3
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Germplasm, chemical constituents, biological activities, utilization, and control of Chinese tallow (Triadica sebifera (L.) Small). Biol Invasions 2016. [DOI: 10.1007/s10530-016-1052-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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4
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Wang HB, Wang XY, Liu LP, Qin GW, Kang TG. Tigliane diterpenoids from the Euphorbiaceae and Thymelaeaceae families. Chem Rev 2015; 115:2975-3011. [PMID: 25906056 DOI: 10.1021/cr200397n] [Citation(s) in RCA: 147] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Hong-Bing Wang
- †Research Center for Translational Medicine, Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai 200092, People's Republic of China
| | - Xiao-Yang Wang
- †Research Center for Translational Medicine, Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai 200092, People's Republic of China.,‡School of Pharmacy, Liaoning University of Traditional Chinese Medicine, Dalian 116600, People's Republic of China
| | - Li-Ping Liu
- †Research Center for Translational Medicine, Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai 200092, People's Republic of China
| | - Guo-Wei Qin
- §Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, People's Republic of China
| | - Ting-Guo Kang
- ‡School of Pharmacy, Liaoning University of Traditional Chinese Medicine, Dalian 116600, People's Republic of China
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Durán-Peña MJ, Botubol Ares JM, Collado IG, Hernández-Galán R. Biologically active diterpenes containing a gem-dimethylcyclopropane subunit: an intriguing source of PKC modulators. Nat Prod Rep 2014; 31:940-52. [DOI: 10.1039/c4np00008k] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
This review describes diterpenes containing thegem-dimethylcyclopropane subunit isolated from natural sources with a special emphasis on their intriguing biological activities as a source of PKC modulators.
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Affiliation(s)
| | | | - Isidro G. Collado
- Department of Organic Chemistry
- Faculty of Science
- University of Cádiz
- , Spain
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6
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Sourbier C, Scroggins BT, Ratnayake R, Prince TL, Lee S, Lee MJ, Nagy PL, Lee YH, Trepel JB, Beutler JA, Linehan WM, Neckers L. Englerin A stimulates PKCθ to inhibit insulin signaling and to simultaneously activate HSF1: pharmacologically induced synthetic lethality. Cancer Cell 2013; 23:228-37. [PMID: 23352416 PMCID: PMC3574184 DOI: 10.1016/j.ccr.2012.12.007] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 10/19/2012] [Accepted: 12/18/2012] [Indexed: 12/31/2022]
Abstract
The natural product englerin A (EA) binds to and activates protein kinase C-θ (PKCθ). EA-dependent activation of PKCθ induces an insulin-resistant phenotype, limiting the access of tumor cells to glucose. At the same time, EA causes PKCθ-mediated phosphorylation and activation of the transcription factor heat shock factor 1, an inducer of glucose dependence. By promoting glucose addiction, while simultaneously starving cells of glucose, EA proves to be synthetically lethal to highly glycolytic tumors.
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Affiliation(s)
- Carole Sourbier
- Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892
| | - Bradley T. Scroggins
- Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892
| | - Ranjala Ratnayake
- Molecular Targets Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702
| | - Thomas L. Prince
- Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892
| | - Sunmin Lee
- Medical Oncology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892
| | - Min-Jung Lee
- Medical Oncology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892
| | | | - Young H. Lee
- Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892
| | - Jane B. Trepel
- Medical Oncology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892
| | - John A. Beutler
- Molecular Targets Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702
| | - W. Marston Linehan
- Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892
| | - Len Neckers
- Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892
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7
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Goel G, Makkar HPS, Francis G, Becker K. Phorbol esters: structure, biological activity, and toxicity in animals. Int J Toxicol 2007; 26:279-88. [PMID: 17661218 DOI: 10.1080/10915810701464641] [Citation(s) in RCA: 230] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Phorbol esters are the tetracyclic diterpenoids generally known for their tumor promoting activity. The phorbol esters mimic the action of diacyl glycerol (DAG), activator of protein kinase C, which regulates different signal transduction pathways and other cellular metabolic activities. They occur naturally in many plants of the family Euphorbiacaeae and Thymelaeaceae. The biological activities of the phorbol esters are highly structure specific. The phorbol esters, even at very low concentrations, show toxicological manifestations in animals fed diets containing them. This toxicity limits the use of many nutritive plants and agricultural by-products containing phorbol esters to be used as animal feed. Therefore, various chemical and physical treatments have been evaluated to extract or inactivate phorbol esters so that seed meals rich in proteins could be used as feed resources. However, not much progress has been reported so far. The detoxifying ability has also been reported in some molluscs and in liver homogenate of mice. Besides, possessing antinutritional and toxic effects, few derivatives of the phorbol esters are also known for their antimicrobial and antitumor activities. The molluscicidal and insecticidal properties of phorbol esters indicate its potential to be used as an effective biopesticide and insecticide.
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Affiliation(s)
- Gunjan Goel
- Institute for Animal Production in the Tropics and Subtropics, University of Hohenheim, Stuttgart, Germany
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8
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Slater SJ, Ho C, Stubbs CD. The use of fluorescent phorbol esters in studies of protein kinase C-membrane interactions. Chem Phys Lipids 2002; 116:75-91. [PMID: 12093536 DOI: 10.1016/s0009-3084(02)00021-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The family of protein kinase C (PKC) isozymes belongs to a growing class of proteins that become active by associating with membranes containing anionic phospholipids, such as phosphatidylserine. Depending on the particular PKC isoform, this process is mediated by Ca(2+)-binding to a C2 domain and interaction of activators such as 1,2-diacyl-sn-glycerol or phorbol esters with tandem C1 domains. This cooperation between the C1 and C2 domains in inducing the association of PKC with lipid membranes provides the energy for a conformational change that consists of the release of a pseudosubstrate sequence from the active site, culminating in activation. Thus, the properties of the interactions of the C1 and C2 domains with membranes, both as isolated domains, and as modules in the full length PKC isoforms, have been the subject of intense scrutiny. Here, we review the findings of studies in which fluorescent phorbol esters have been utilized to probe the properties of the C1 domains of PKC with respect to the interaction with activators, the subsequent interaction with membranes, and the role of the activating conformational change that leads to activation.
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Affiliation(s)
- Simon J Slater
- Department of Anatomy, Pathology and Cell Biology, Thomas Jefferson University, Room 271 JAH, 1020 Locust St., Philadelphia, PA 19107, USA
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9
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Imam A, Hoyos B, Swenson C, Levi E, Chua R, Viriya E, Hammerling U. Retinoids as ligands and coactivators of protein kinase C alpha. FASEB J 2001; 15:28-30. [PMID: 11099483 DOI: 10.1096/fj.00-0329fje] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Whereas retinoic acids control nuclear events, a second class of retinol metabolites, that is, the hydroxylated forms exemplified by 14-hydroxy-retro-retinol (HRR), operate primarily in the cytoplasm. They function as regulatory cofactors for cell survival/cell death decisions. In accordance with these biological aspects, we demonstrate that these retinoids bound protein kinase C (PKC) alpha with nanomolar affinity and markedly enhance the activation of PKC alpha and the entire downstream MAP kinase pathway by reactive oxygen species. HRR was 10 times more efficient than retinol, and the optimum doses are 10-7 and 10-6 M, respectively. PKC alpha activation was reversed rapidly by imposition of reducing conditions. The retinoid binding site was mapped to the first cysteine-rich region in the regulatory domain, C1A, yet was distinct from the binding sites of diacylglycerol and phorbol esters. The C1B domain bound retinoids poorly. The emerging theme is that retinoids serve as redox regulators of protein kinase C.
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Affiliation(s)
- A Imam
- Program in Immunology, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA
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10
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Slater SJ, Ho C, Kelly MB, Larkin JD, Taddeo FJ, Yeager MD, Stubbs CD. Protein kinase Calpha contains two activator binding sites that bind phorbol esters and diacylglycerols with opposite affinities. J Biol Chem 1996; 271:4627-31. [PMID: 8617724 DOI: 10.1074/jbc.271.9.4627] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Based on marked differences in the enzymatic properties of diacylglycerols compared with phorbol ester-activated protein kinase C (PKC), we recently proposed that activation induced by these compounds may not be equivalent (Slater, S. J., Kelly, M. B., Taddeo, F. J., Rubin, E., and Stubbs, C. D. (1994) J. Biol. Chem. 269, 17160-17165). In the present study, direct evidence is provided showing that phorbol esters and diacylglycerols bind simultaneously to PKC alpha. Using a novel binding assay employing the fluorescent phorbol ester, sapintoxin-D (SAPD), evidence for two sites of high and low affinity was obtained. Thus, both binding and activation dose-response curves for SAPD were double sigmoidal, which was also observed for dose-dependent activation by the commonly used phorbol ester, 4beta-12-O-tetradecanoylphorbol-13-acetate (TPA). TPA removed high affinity SAPD binding and also competed for the low affinity site. By contrast with TPA, low affinity binding of SAPD was inhibited by sn-1,2-dioleoylglycerol (DAG), while binding to the high affinity site was markedly enhanced. Again contrasting with both TPA and DAG, the potent PKC activator, bryostatin-I (B-I), inhibited SAPD binding to its high affinity site, while low affinity binding was unaffected. Based on these findings, a model for PKC activation is proposed in which binding of one activator to the low affinity site allosterically promotes binding of a second activator to the high affinity site, resulting in an enhanced level of activity. Overall, the results provide direct evidence that PKCalpha contains two distinct binding sites, with affinities that differ for each activator in the order: DAG > phorbol ester > B-I and B-I > phorbol ester > DAG, respectively.
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Affiliation(s)
- S J Slater
- Department of Pathology and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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11
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Wang JP, Raung SL, Kuo YH, Teng CM. Daphnoretin-induced respiratory burst in rat neutrophils is, probably, mainly through protein kinase C activation. Eur J Pharmacol 1995; 288:341-8. [PMID: 7774678 DOI: 10.1016/0922-4106(95)90047-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Daphnoretin, a dicoumarin isolated from Wikstroemia indica C.A. Mey. (Thymelaceae), induced superoxide anion (O2-) formation in rat neutrophils in a concentration-dependent manner. Addition of staurosporine reduced daphnoretin-induced respiratory burst. Removal of extracellular free Ca2+ by EGTA did not affect the respiratory burst of neutrophils in response to daphnoretin. Prior exposure of neutrophils to phorbol 12-myristate 13-acetate (PMA) or daphnoretin reduced the O2- formation caused by a subsequent challenge with PMA and daphnoretin, but potentiated the response caused by a subsequent addition of formyl-Met-Leu-Phe (fMLP). Like PMA, daphnoretin did not increase the [Ca2+]i during cell activation. In neutrophil suspension, daphnoretin increased the membrane associated protein kinase C activity. In the presence of Ca2+ and phosphatidyl-serine, daphnoretin also activated protein kinase C isolated from cytosolic fraction of resting neutrophils. Staurosporine inhibited the direct activation of protein kinase C caused by daphnoretin as well as by PMA. Daphnoretin reduced the [3H]Phorbol-12,13-dibutyrate ([3H]PDB) binding to the neutrophil cytosolic protein kinase C in a concentration-dependent manner with an IC50 value of 1.77 +/- 0.37 microM. These results indicate that daphnoretin, like PMA, may direct activation of protein kinase C which in turn activated NADPH oxidase and elicited respiratory burst.
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Affiliation(s)
- J P Wang
- Department of Medical Research, Taichung Veterans General Hospital, Taiwan, China
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12
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Merritt JE, Moores KE, Evans AT, Sharma P, Evans FJ, MacPhee CH. Involvement of calcium in modulation of neutrophil function by phorbol esters that activate protein kinase C isotypes and related enzymes. Biochem J 1993; 289 ( Pt 3):919-26. [PMID: 8435086 PMCID: PMC1132263 DOI: 10.1042/bj2890919] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
In this study, the effects of a series of phorbol esters with different spectra of biological activities and different patterns of activation of the isoenzymes of protein kinase C (PKC) have been studied in human neutrophils. The aim was to gain more information on which isoenzymes of PKC are involved in neutrophil activation, specifically inhibition of fMet-Leu-Phe (fMLP)-stimulated bivalent cation influx and stimulation of O2-. release (either alone or potentiation of the response to fMLP). Prior addition of both phorbol 12-myristate 13-acetate (PMA) and sapintoxin A (SAPA) inhibited fMLP-stimulated Mn2+ influx. Higher concentrations of resiniferatoxin (RX) were also inhibitory, inhibition being more apparent at longer preincubation times. However, 12-deoxyphorbol 13-O-phenylacetate (DOPPA) showed only a slight inhibitory effect and required a prolonged preincubation. PMA, SAPA and RX, but not DOPPA, stimulated O2-. release by themselves. Lower concentrations of PMA, SAPA and RX, which were ineffective alone, considerably potentiated O2-. release stimulated by fMLP, whereas DOPPA had little or no effect. These results rule out a major role for PKC-delta (not activated by SAPA) and PKC-beta 1 (activated by DOPPA), but suggest the involvement of RX kinase in addition to PKC in the inhibition of fMLP-stimulated Mn2+ influx and potentiation of fMLP-stimulated O2-. release. However, when the cytosolic free Ca2+ concentration ([Ca2+]i) was elevated with the Ca2+ ionophore ionomycin, DOPPA was able to stimulate O2-. release, which probably reflects the known Ca2+ requirement for activation of PKC-beta 1 by DOPPA in vitro. The effects of the other phorbols were also enhanced when [Ca2+]i was elevated; all of the phorbols synergize, to variable extents, with Ca2+ to activate PKC in vitro. Enhancement of RX-stimulated O2- release by elevation of [Ca2+]i was unexpected, since RX kinase has been reported to be inhibited by high concentrations of Ca2+ in vitro. Finally, use of fura-2 and SK&F 96365 to manipulate the fMLP-stimulated rise in [Ca2+]i showed that when fMLP was able to evoke its normal rise in [Ca2+]i (to a peak of 700-900 nM), O2-. release was potentiated by PMA, SAPA and RX. However, when fMLP was only able to evoke a small increase in [Ca2+]i (to a peak of 400 nM), potentiation by PMA was unaffected but potentiation by SAPA and RX was considerably reduced. This observation agrees with published data demonstrating that activation of PKC in vitro by SAPA is more Ca(2+)-dependent than activation by PMA.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- J E Merritt
- SmithKline Beecham Pharmaceuticals Ltd., The Frythe, Welwyn, Herts, U.K
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13
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Brooks G, Goss MW, Hart IR. Differential induction of 12-O-tetradecanoylphorbol-13-acetate sequence gene expression in murine melanocytes and melanoma cells. Mol Carcinog 1992; 5:328-33. [PMID: 1379817 DOI: 10.1002/mc.2940050414] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We previously showed that growth of the nontumorigenic, immortal murine melanocyte line Mel-ab correlates with the depletion of protein kinase C (PKC), whereas quiescence is associated with elevated levels of this enzyme (Brooks G, et al., Cancer Res 51: 3281-3288, 1991). Here we report responses that occur in these cells downstream of PKC activation or downregulation. We examined induction of 12-O-tetradecanoylphorbol-13-acetate (TPA)-inducible sequence (TIS) gene expression in Mel-ab melanocytes and in their transformed counterparts, B16 melanoma cells. Exposure of quiescent Mel-ab cells to the PKC-activating phorbol esters TPA or sapintoxin A at 81 nM for 2 h increased levels of mRNA for six of seven TIS genes examined (twofold to 80-fold increase in steady-state RNA levels for TIS 1, 7, 8, 11, 21, and 28 (c-fos); TIS 10 expression was not affected). No induction of TIS gene expression was observed either in growing Mel-ab cells maintained in 324 nM phorbol 12,13-dibutyrate or in B16 cells previously unexposed to phorbol esters, in which normal PKC levels were endogenously depressed. The cAMP-elevating agents choleratoxin (10 nM) and dibutyryl cyclic AMP (2.5 mM) increased levels of TIS mRNA (with the exception of TIS 10) in both proliferating Mel-ab and B16 cells, suggesting that downregulation of the PKC pathway is specific and not a consequence of a general inhibition of all signalling pathways.
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MESH Headings
- 3T3 Cells
- Animals
- Blotting, Northern
- Bucladesine/pharmacology
- Cell Line, Transformed
- Cells, Cultured
- Cycloheximide/pharmacology
- Gene Expression/drug effects
- Genes, fos
- Melanocytes/drug effects
- Melanocytes/physiology
- Melanoma, Experimental/genetics
- Mice
- Molecular Weight
- Phorbol 12,13-Dibutyrate/pharmacology
- RNA/genetics
- RNA/isolation & purification
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Tetradecanoylphorbol Acetate/pharmacology
- Transcription, Genetic/drug effects
- Tumor Cells, Cultured
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Affiliation(s)
- G Brooks
- Biology of Metastasis Laboratory, Imperial Cancer Research Fund, London, United Kingdom
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14
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Ryves WJ, Evans AT, Olivier AR, Parker PJ, Evans FJ. Activation of the PKC-isotypes alpha, beta 1, gamma, delta and epsilon by phorbol esters of different biological activities. FEBS Lett 1991; 288:5-9. [PMID: 1879564 DOI: 10.1016/0014-5793(91)80989-g] [Citation(s) in RCA: 150] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Phorbol esters, tetradecanoylphorbolacetate, sapintoxin-A, 12-deoxyphorbol-phenylacetate, 12-deoxyphorbol-phenylacetate-20-acetate, thymeleatoxin and resiniferatoxin were investigated for their abilities to activate the PKC-isotypes alpha, beta 1, gamma, delta and epsilon. PKC-isotypes were grouped into two classes on the basis of Ca2+ requirements for activation by phorbol esters; alpha, beta 1, and gamma being Ca(2+)-dependent forms and delta and epsilon being Ca(2+)-independent. PKC-isotype selective activation by phorbol esters was observed in that SAPA failed to activate PKC-delta up to a concentration of 1000 ng.ml-1 and DOPPA only activated PKC-beta 1 over the same range of concentrations.
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Affiliation(s)
- W J Ryves
- Department of Pharmacognosy, School of Pharmacy, University of London, UK
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15
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Brooks SF, Gordge PC, Toker A, Evans AT, Evans FJ, Aitken A. Platelet protein phosphorylation and protein kinase C activation by phorbol esters with different biological activity and a novel synergistic response with Ca2+ ionophore. EUROPEAN JOURNAL OF BIOCHEMISTRY 1990; 188:431-7. [PMID: 2108026 DOI: 10.1111/j.1432-1033.1990.tb15420.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Phorbol esters with different biological activities have been tested for their ability to induce the phosphorylation of human platelet proteins. We have shown that only the potent platelet aggregatory phorbol esters were able to stimulate the phosphorylation of proteins of 76, 68, 47, 30 and 20 kDa in intact platelets. The ability of these esters to stimulate phosphorylation of the 47-kDa protein ('p47') correlated with their ability to cause platelet aggregation. When a non-platelet aggregatory deoxyphorbol (12-deoxyphorbol 13-phenylacetate 20-acetate) was combined with a subthreshold dose of the Ca2+ ionophore, A23187, a large increase in phosphorylation of p47 and a fourfold decrease in Ka was observed. This was in contrast to a barely detectable stimulation of phosphorylation at micromolar levels of this phorbol ester in the absence of the ionophore. This synergism was not evident for the potent platelet aggregatory derivatives. The Ka for DOPPA with a mixture of total platelet protein kinase C was 530 nM in the absence of calcium decreasing to 120 nM in the presence of calcium. In the presence of calcium, 12-deoxyphorbol 13-phenylacetate 20-acetate was shown to stimulate preferentially one of the isoforms of protein kinase C.
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Affiliation(s)
- S F Brooks
- Laboratory of Protein Structure, National Institute for Medical Research, Mill Hill, London, England
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Brooks G, Birch M, Hart IR. Effects of biologically active tumour-promoting and non-promoting phorbol esters on in vitro growth of melanocytic cells. PIGMENT CELL RESEARCH 1990; 3:98-100. [PMID: 2385570 DOI: 10.1111/j.1600-0749.1990.tb00328.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Sapintoxin A (SAP A), a naturally occurring biologically active but non-promoting phorbol ester, acts as an effective in vitro mitogen for freshly derived human melanocytes. Seven days after addition of 50 nM SAP A there was a four to fivefold increase in melanocyte number over that observed in untreated control cultures comparable to that achieved with a 50 nM concentration of 12-0-tetradecanoylphorbol 13-acetate (TPA). The fluorescent stage 2 promoter sapintoxin D (SAP D) also supported the growth of these cells, with a 50 nM dose producing an increase in cell number comparable to that observed with 200 nM TPA. Similar results were obtained with an established, but non-tumorigenic, line of murine melanocytes. The same compounds exerted a potent anti-proliferative effect against transformed melanocyte lines of murine and human origin associated with morphological alterations and an increase in melanin production consistent with induced cytodifferentiation.
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Affiliation(s)
- G Brooks
- Biology of Metastasis Laboratory, Imperial Cancer Research Fund, London, England
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Brooks G, Evans AT, Aitken A, Evans FJ. Sapintoxin A. A fluorescent phorbol ester that is a potent activator of protein kinase C but is not a tumour promoter. Cancer Lett 1987; 38:165-70. [PMID: 3690506 DOI: 10.1016/0304-3835(87)90211-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In this communication we report on the activity of the naturally occurring, highly fluorescent phorbol ester Sapintoxin A (12-o-[2-methylaminobenzoate]-4-deoxyphorbol 13-acetate). This compound potently activates the enzyme protein kinase C (PKC) (Ka 76 nM) but is neither a complete nor second-stage tumour promoter in traditional Berenblum tests. Sapintoxin A has properties in common with promoters such as 12-o-tetradecanoylphorbol 13-acetate (TPA) in that it will induce erythema in vivo, induce lymphocyte mitogenesis in vitro and cause aggregation of human and rabbit platelets. Accordingly, Sapintoxin A is a suitable negative control compound for biochemical studies concerning the involvement of PKC in tumour promotion and cell proliferation.
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Affiliation(s)
- G Brooks
- Department of Pharmacognosy, School of Pharmacy, University of London, U.K
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Brooks SF, Evans FJ, Aitken A. The stimulation of phosphorylation of intracellular proteins in GH3 rat pituitary tumour cells by phorbol esters of distinct biological activity. FEBS Lett 1987; 224:109-16. [PMID: 3678485 DOI: 10.1016/0014-5793(87)80431-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Using a pituitary tumour cell line (GH3), we have studied the phosphorylation of intracellular proteins induced by phorbol esters of diverse biological activity. All the active phorbol esters, including the weakly tumour-promoting but non-platelet aggregatory compound DOPPA, stimulated the phosphorylation of a cytosolic 80 kDa protein. A protein of this molecular mass has been suggested to be a marker of PKC activity. In contrast, only TPA and the non-tumour promoting but highly active phorbol ester SAP A stimulated the phosphorylation of a 130 kDa membrane protein. The results suggest that these phorbol esters activate PKC, but induce the differential phosphorylation of a variety of intracellular proteins.
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Affiliation(s)
- S F Brooks
- Laboratory of Protein Structure, National Institute for Medical Research, Mill Hill, London
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Brooks G, Morrice NA, Ellis C, Aitken A, Evans AT, Evans FJ. Toxic phorbol esters from Chinese tallow stimulate protein kinase C. Toxicon 1987; 25:1229-33. [PMID: 3433294 DOI: 10.1016/0041-0101(87)90141-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Phorbol esters were isolated from the seeds of Chinese tallow (Sapium sebiferum L. Roxb.). These compounds were based on the tigliane nuclei, 4-deoxyphorbol, 12-deoxyphorbol and 4,20-dideoxy-5-hydroxyphorbol. The pro-inflammatory activity (ID50) of the pure compounds was between 0.042 and 2.6 nmoles per ear. Protein kinase C activation assays were carried out on samples of enzyme purified from mammalian brain and the activities (Ka) were in the range 76-176 nM. The 4,20-dideoxy-5-hydroxy analogue was inactive in both tests. Chinese tallow, which is used as a substitute for linseed oil, may represent an industrial toxic hazard in terms of both pro-inflammatory and tumour-promoting effects.
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Affiliation(s)
- G Brooks
- Department of Pharmacognosy and Pharmaceutical Chemistry, School of Pharmacy, University of London, U.K
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Edwards MC, Evans FJ, Barrett ML, Gordon D. Structural correlations of phorbol-ester-induced stimulation of PGE2 production by human rheumatoid synovial cells. Inflammation 1985; 9:33-8. [PMID: 3856558 DOI: 10.1007/bf00915409] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Eight phorbol esters were studied for their ability to stimulate prostaglandin production in human rheumatoid synovial cells over the dose range 0.1 ng to 1.0 micrograms. These derivatives were based upon phorbol, 4-deoxyphorbol, and 12-deoxyphorbol nuclei. This activity was structurally dependent and, although it did not correlate with the actions of the same compounds to induce erythema in vivo, it did correlate with their ability to stimulate human lymphocyte mitogenesis. Stimulation of PGE2 production by a phorbol and a 12-deoxyphorbol analog was inhibited in this system by both indomethacin and dexamethasone.
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Edwards MC, Taylor SE, Williamson EM, Evans FJ. New phorbol and deoxyphorbol esters: isolation and relative potencies in inducing platelet aggregation and erythema of skin. ACTA PHARMACOLOGICA ET TOXICOLOGICA 1983; 53:177-87. [PMID: 6637507 DOI: 10.1111/j.1600-0773.1983.tb01122.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Diester diterpenes based upon phorbol, 4-deoxyphorbol, 4 alpha-deoxyphorbol, 4-deoxy-5-hydroxyphorbol and 4,20-dideoxy-5-hydroxyphorbol were isolated from the fruit oil of Sapium indicum. Corresponding tri- and tetra-esters were produced by acetylation and mono-esters by selective hydrolysis. Twenty-six compounds were tested for production of erythema in vivo and induction of human and rabbit platelet aggregation in vitro. The flatter shape of the AB-ring trans compounds is necessary for interaction of phorbolesters at their receptor in that the cis analogues were inactive. The tertiary C-4 hydroxy group of phorbol was not necessary for activity although the 4-deoxy derivatives were less potent than the 4-hydroxy diterpenes. A primary hydroxy group at C-20 was essential for biological activity because the methyl and aldehyde derivatives of this position were inactive. The C-20 acetates were also inactive on platelets, but they did produce erythema, possibly because of the removal of the ester due to lipase activity in the skin. 5-hydroxy-analogues which undergo intramolecular hydrogen bonding had greatly reduced activities in both systems. Membrane stabilisers, phospholipase A2 and calmodulin inhibitors were antagonists for phorbol esters in platelet aggregation tests, whilst cyclo-oxygenase inhibitors and free radical scavengers had no inhibitory effects. Consequently, one electron withdrawal and free radical formation plays no part in the biological activity of these compounds.
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Evans FJ, Taylor SE. Pro-inflammatory, tumour-promoting and anti-tumour diterpenes of the plant families Euphorbiaceae and Thymelaeaceae. FORTSCHRITTE DER CHEMIE ORGANISCHER NATURSTOFFE = PROGRESS IN THE CHEMISTRY OF ORGANIC NATURAL PRODUCTS. PROGRES DANS LA CHIMIE DES SUBSTANCES ORGANIQUES NATURELLES 1983; 44:1-99. [PMID: 6360830 DOI: 10.1007/978-3-7091-8714-2_1] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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