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Szabo A, Fekete T, Koncz G, Kumar BV, Pazmandi K, Foldvari Z, Hegedus B, Garay T, Bacsi A, Rajnavolgyi E, Lanyi A. RIG-I inhibits the MAPK-dependent proliferation of BRAF mutant melanoma cells via MKP-1. Cell Signal 2016; 28:335-347. [PMID: 26829212 DOI: 10.1016/j.cellsig.2016.01.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 01/22/2016] [Accepted: 01/28/2016] [Indexed: 12/20/2022]
Abstract
BACKGROUND BRAF-mutant melanoma is characterized by aggressive metastatic potential and therapeutic resistance. The innate immune receptor RIG-I has emerged as a potential target in melanoma therapies but the contributing pathways involved in anti-cancer activity are poorly characterized. METHODS Baseline and ATRA-induced expression of RIG-I in nine (3 wild type and 6 BRAF-mutant) melanoma cell lines was measured with Q-PCR and Western blot. Ligand-specific stimulation of RIG-I was detected by Q-PCR and ELISA. Activation of the RIG-I-coupled IRF3, NF-κB and MAPK pathways was tested with protein array and Western blot. Cell proliferation and apoptosis was monitored by flow cytometry and cell counting. Down modulation of MKP-1 expression in melanoma cells was performed by specific siRNA. RESULTS Short-term ATRA pre-treatment increases the expression of RIG-I in BRAF-mutant melanoma cells. Specific activation of RIG-I by 5'ppp-dsRNA leads to increased activity of the IRF3-IFNβ pathway but does not influence NF-κB signaling. RIG-I mediates the targeted dephosphorylation of several MAPKs (p38, RSK1, GSK-3α/β, HSP27) via the endogenous regulator MKP-1 resulting in decreased melanoma cell proliferation. CONCLUSION RIG-I has the potential to exert anticancer activity in BRAF-mutant melanoma via controlling IFNβ production and MAPK signaling. This is the first study showing that RIG-I activation results in MKP-1-mediated inhibition of cell proliferation via controlling the p38-HSP27, c-Jun and rpS6 pathways thus identifying RIG-I and MKP-1 as novel and promising therapeutical targets.
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Affiliation(s)
- Attila Szabo
- Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary; Sapientia Hungarian University of Transylvania, Department of Bioengineering, Miercurea-Ciuc, Romania.
| | - Tunde Fekete
- Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Gabor Koncz
- Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary; Sapientia Hungarian University of Transylvania, Department of Bioengineering, Miercurea-Ciuc, Romania
| | - Brahma V Kumar
- Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Kitti Pazmandi
- Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Zsofia Foldvari
- Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Balazs Hegedus
- 2nd Institute of Pathology, Semmelweis University, Budapest, Hungary; MTA-SE Molecular Oncology Research Group, Hungarian Academy of Sciences, Budapest, Hungary
| | - Tamas Garay
- 2nd Institute of Pathology, Semmelweis University, Budapest, Hungary; MTA-SE Molecular Oncology Research Group, Hungarian Academy of Sciences, Budapest, Hungary
| | - Attila Bacsi
- Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary; Sapientia Hungarian University of Transylvania, Department of Bioengineering, Miercurea-Ciuc, Romania
| | - Eva Rajnavolgyi
- Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary; Sapientia Hungarian University of Transylvania, Department of Bioengineering, Miercurea-Ciuc, Romania
| | - Arpad Lanyi
- Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary; Sapientia Hungarian University of Transylvania, Department of Bioengineering, Miercurea-Ciuc, Romania
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