| Cyclosporin A up-regulates and activates protein kinase C-zeta in EBV-infected and EBV-transformed human B-cells. | |
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MedLine Citation:
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PMID: 18486150 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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BACKGROUND: Protein Kinase C (PKC) is a family of enzymes that plays a key role in cell signaling pathways leading to cellular activation and proliferation. Conventional PKC (cPKC) is dependent on calcium for activation. We have proposed that cyclosporin A (CsA), despite being a calcineurin inhibitor, will activate PKC in B cells, thus promoting Epstein-Barr virus (EBV)-induced transformation. Here we show that CsA promoted atypical PKC isoform PKC-zeta in B cells. MATERIALS AND METHODS: Western-blot was used to assay PKC-zeta protein level in EBV-B cells. Confocal microscopy was used to assay PKC-zeta translocation from cytosol to cell membrane, a known process of PKC activation. RESULTS: CsA (500 ng/mL) time dependently increased PKC-zeta from control of 7055 units to 7145, 10,805, 10,914, and 12,705 units, respectively, after 15 min, 1 h, 12 h, and 24 h of incubation in EBV-transformed human B-cell line (LCL). CsA increased PKC-zeta expression was inhibited 50% by Vit.E (40 microM) indicating that this effect may be due to oxidative stress induced by CsA. Indeed, after oxidant H(2)O(2) (0.1 mM) treatment, PKC-zeta protein level in LCL cells increased 124%, 257%, 349%, and 359% after 15 min, 1 h, 12 h, and 24 h of culture compared with control. Addition of Vit.E (40 microM) in H(2)O(2) (0.1 mM) treatment and then with Vit.E in the culture decreased PKC-zeta level in LCL cells 26%, 20%, 41%, and 60% after 15 min, 1 h, 12 h, and 24 h of culture. In confocal microscopy in Jurkat T cell line, phorbol 12-myristate 13-acetate (PMA) activated cPKC isoform PKCalpha after 30 min treatment and activated PKC-zeta after 60 min treatment. CsA inhibited PMA activation of PKC-alpha, but not PKC-zeta. CsA alone did not activate PKC-alpha or PKC-zeta in Jurkat T cells. In LCL and in EBV-infected human B-cells, PMA stimulated PKC-alpha activation after 30 min treatment and stimulated PKC-zeta activation after 60 min treatment. CsA inhibited PMA activation of PKC-alpha, but not PKC-zeta. In addition, CsA activated PKC-zeta in the EBV-transformed and EBV-infected human B cells. CONCLUSION: These experiments show that CsA-induced oxidative stress caused PKC-zeta up-regulation in LCL cells, and show the differential effect of CsA in the PKC signaling pathways in T cells versus B cells. CsA-induced PKC-zeta activation may be an important signaling step in EBV-induced post-transplant lymphoproliferative disorders. |
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Authors:
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Changguo Chen; Thomas D Johnston; Hoonbae Jeon; Roberto Gedaly; Patrick McHugh; Dinesh Ranjan |
Publication Detail:
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Type: Journal Article Date: 2008-04-08 |
Journal Detail:
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Title: The Journal of surgical research Volume: 153 ISSN: 1095-8673 ISO Abbreviation: J. Surg. Res. Publication Date: 2009 May |
Date Detail:
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Created Date: 2009-04-13 Completed Date: 2009-05-07 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0376340 Medline TA: J Surg Res Country: United States |
Other Details:
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Languages: eng Pagination: 156-61 Citation Subset: IM |
Affiliation:
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Department of Surgery, University of Kentucky, College of Medicine, Lexington, KY 40536, USA. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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B-Lymphocytes
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drug effects*,
virology Cells, Cultured Cyclosporine / pharmacology* Epstein-Barr Virus Infections / metabolism* Herpesvirus 4, Human* Humans Immunosuppressive Agents / pharmacology* Oxidative Stress Protein Isoforms Protein Kinase C / metabolism* Signal Transduction Up-Regulation |
| Chemical | |
Reg. No./Substance:
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0/Immunosuppressive Agents; 0/Protein Isoforms; 59865-13-3/Cyclosporine; EC 2.7.11.1/protein kinase C zeta; EC 2.7.11.13/Protein Kinase C |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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