NOS2 expression in glioma cell lines and glioma primary cell cultures: correlation with neurosphere generation and SOX-2 expression

// Paola Palumbo 1 , Gianfranca Miconi 1 , Benedetta Cinque 1 , Francesca Lombardi 1 , Cristina La Torre 1 , Soheila Raysi Dehcordi 1, 2 , Renato Galzio 1, 2 , Annamaria Cimini 1, 3, 4 , Antonio Giordano 3, 5 , Maria Grazia Cifone 1 1 Department of Life, Health and Environmental Sciences, University of L’Aquila, L’Aquila, Italy 2 Department of Surgery, Operative Unit of Neurosurgery, San Salvatore Hospital, L’Aquila, Italy 3 Sbarro Institute for Cancer Research and Molecular Medicine and Center for Biotechnology, Temple University, Philadelphia, PA, USA 4 National Institute for Nuclear Physics (INFN), Gran Sasso National Laboratory (LNGS), Assergi, Italy 5 Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy Correspondence to: Paola Palumbo, email: paola.palumbo@univaq.it Keywords: glioma, primary cultures, cancer stem cell, NOS2, SOX-2 Received: December 07, 2016      Accepted: February 15, 2017      Published: March 10, 2017 ABSTRACT Nitric oxide has been implicated in biology and progression of glioblastoma (GBM) being able to influence the cellular signal depending on the concentration and duration of cell exposure. NOS2 (inducible nitric oxide synthase) have been proposed as a component of molecular profile of several tumors, including glioma, one of the most aggressive primary brain tumor featuring local cancer stem cells responsible for enhanced resistance to therapies and for tumor recurrence. Here, we investigated the NOS2 mRNA expression by reverse transcription-PCR in human glioma primary cultures at several grade of malignancy and glioma stem cell (GSC) derived neurospheres. Glioma cell lines were used as positive controls both in terms of stemness marker expression that of capacity of generating neurospheres. NOS2 expression was detected at basal levels in cell lines and primary cultures and appeared significantly up-regulated in cultures kept in the specific medium for neurospheres. The immunofluorescence analysis of all cell cultures to evaluate the levels of SOX-2, a stemness marker aberrantly up-regulated in GBM, was also performed. The potential correlation between NOS2 expression and ability to generate neurospheres and between NOS2 and SOX-2 levels was also verified. The results show that the higher NOS2 expression is detected in all primary cultures able to arise neurosphere. A high and significant correlation between NOS2 expression and SOX-2 positive cells (%) in all cell cultures maintained in standard conditions has been observed. The results shed light on the potential relevance of NOS2 as a prognostic factor for glioma malignancy and recurrence.