Inhibition of chemerin/CMKLR1 axis in neuroblastoma cells reduces clonogenicity and cell viability in vitro and impairs tumor growth in vivo

// Conny Tummler 1 , Igor Snapkov 1 , Malin Wickstrom 2 , Ugo Moens 1 , Linda Ljungblad 2 , Lotta Helena Maria Elfman 2 , Jan-Olof Winberg 3 , Per Kogner 2 , John Inge Johnsen 2 and Baldur Sveinbjornsson 1, 2 1 Molecular Inflammation Research Group, Department of Medical Biology, Faculty of Health Science, University of Tromso, Tromso, Norway 2 Childhood Cancer Research Unit, Department of Women’s and Children’s Health, Karolinska Institutet, Stockholm, Sweden 3 Tumor Biology Research Group, Department of Medical Biology, Faculty of Health Science, University of Tromso, Tromso, Norway Correspondence to: Conny Tummler, email: conny.tummler@uit.no Keywords: pediatric cancer, neuroblastoma, inflammation, GPCR, chemerin Received: December 10, 2016      Accepted: July 06, 2017      Published: July 27, 2017 ABSTRACT Pro-inflammatory cells, cytokines, and chemokines are essential in promoting a tumor supporting microenvironment. Chemerin is a chemotactic protein and a natural ligand for the receptors CMKLR1, GPR1, and CCRL2. The chemerin/CMKLR1 axis is involved in immunity and inflammation, and it has also been implicated in obesity and cancer. In neuroblastoma, a childhood tumor of the peripheral nervous system we identified correlations between high CMKLR1 and GPR1 expression and reduced overall survival probability. CMKLR1, GPR1, and chemerin RNA and protein were detected in neuroblastoma cell lines and neuroblastoma primary tumor tissue. Chemerin induced calcium mobilization, increased MMP-2 synthesis as well as MAP-kinase- and Akt-mediated signaling in neuroblastoma cells. Stimulation of neuroblastoma cells with serum, TNFα or IL-1β increased chemerin secretion. The small molecule CMKLR1 antagonist α-NETA reduced the clonogenicity and viability of neuroblastoma cell lines indicating the chemerin/CMKLR1 axis as a promoting factor in neuroblastoma tumorigenesis. Furthermore, nude mice carrying neuroblastoma SK-N-AS cells as xenografts showed impaired tumor growth when treated daily with α-NETA from day 1 after tumor cell injection. This study demonstrates the potential of the chemerin/CMKLR1 axis as a prognostic factor and possible therapeutic target in neuroblastoma.