Attila Szabo1, Tunde Fekete2, Gabor Koncz3, Brahma V Kumar2, Kitti Pazmandi2, Zsofia Foldvari2, Balazs Hegedus4, Tamas Garay4, Attila Bacsi3, Eva Rajnavolgyi3, Arpad Lanyi3. 1. Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary; Sapientia Hungarian University of Transylvania, Department of Bioengineering, Miercurea-Ciuc, Romania. Electronic address: szattila@med.unideb.hu. 2. Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary. 3. Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary; Sapientia Hungarian University of Transylvania, Department of Bioengineering, Miercurea-Ciuc, Romania. 4. 2nd Institute of Pathology, Semmelweis University, Budapest, Hungary; MTA-SE Molecular Oncology Research Group, Hungarian Academy of Sciences, Budapest, Hungary.
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.
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.
Authors: Melissa M Linehan; Thayne H Dickey; Emanuela S Molinari; Megan E Fitzgerald; Olga Potapova; Akiko Iwasaki; Anna M Pyle Journal: Sci Adv Date: 2018-02-21 Impact factor: 14.136
Authors: Attila Szabo; Attila Kovacs; Jordi Riba; Srdjan Djurovic; Eva Rajnavolgyi; Ede Frecska Journal: Front Neurosci Date: 2016-09-14 Impact factor: 4.677