Expression of S1P metabolizing enzymes and receptors correlate with survival time and regulate cell migration in glioblastoma multiforme

// Sandra Bien-Moller 1, 2 , Sandra Lange 1 , Tobias Holm 1 , Andreas Bohm 1 , Heiko Paland 1, 2 , Johannes Kupper 1 , Susann Herzog 1, 2 , Kerstin Weitmann 4 , Christoph Havemann 4 , Silke Vogelgesang 3 , Sascha Marx 2 , Wolfgang Hoffmann 4 , Henry W.S. Schroeder 2 , Bernhard H. Rauch 1 1 Department of Pharmacology, University Medicine Greifswald, Greifswald, Germany 2 Department of Neurosurgery, University Medicine Greifswald, Greifswald, Germany 3 Institute of Pathology, Department of Neuropathology, University Medicine Greifswald, Greifswald, Germany 4 Institute for Community Medicine, University Medicine Greifswald, Greifswald, Germany Correspondence to: Sandra Bien-Moller, e-mail: sbien@uni-greifswald.de Keywords: glioblastoma multiforme, sphingosine-1-phosphate, S1P receptor signaling Received: August 03, 2015      Accepted: January 27, 2016      Published: February 13, 2016 ABSTRACT A signaling molecule which is involved in proliferation and migration of malignant cells is the lipid mediator sphingosine-1-phosphate (S1P). There are hints for a potential role of S1P signaling in malignant brain tumors such as glioblastoma multiforme (GBM) which is characterized by a poor prognosis. Therefore, a comprehensive expression analysis of S1P receptors (S1P 1 -S1P 5 ) and S1P metabolizing enzymes in human GBM ( n = 117) compared to healthy brain ( n = 10) was performed to evaluate their role for patient´s survival. Furthermore, influence of S1P receptor inhibition on proliferation and migration were studied in LN18 GBM cells. Compared to control brain, mRNA levels of S1P 1 , S1P 2 , S1P 3 and S1P generating sphingosine kinase-1 were elevated in GBM. Kaplan-Meier analyses demonstrated an association between S1P 1 and S1P 2 with patient´s survival times. In vitro , an inhibitory effect of the SphK inhibitor SKI-II on viability of LN18 cells was shown. S1P itself had no effect on viability but stimulated LN18 migration which was blocked by inhibition of S1P 1 and S1P 2 . The participation of S1P 1 and S1P 2 in LN18 migration was further supported by siRNA-mediated silencing of these receptors. Immunoblots and inhibition experiments suggest an involvement of the PI3-kinase/AKT1 pathway in the chemotactic effect of S1P in LN18 cells. In summary, our data argue for a role of S1P signaling in proliferation and migration of GBM cells. Individual components of the S1P pathway represent prognostic factors for patients with GBM. Perspectively, a selective modulation of S1P receptor subtypes could represent a therapeutic approach for GBM patients and requires further evaluation.