P2X7 receptor as key modulator of PI3K/HIF1a/GSK3b metabolic pathway in neuroblastoma

Neuroblastoma is a common and aggressive extra cranial solid tumor in childhood and still leads to death in 40% of the cases. Aim of our studies was to investigate the role of P2X7 receptor in neuroblastoma biology. Recent studies showed P2X7 expression both in neuroblastoma patients and cell lines (1-2). However, a deeper investigation on P2X7 receptor role in neuroblastoma tumorigenesis is missing. Analysis of an Affimetrix based database allowed us to relate P2X7 mRNA expression with decreased overall survival of stage IV neuroblastoma patients. Expression of P2X7 receptor (P2X7R) is known to drive proliferation of tumor cells by modulating NFATc1 pathway via Ca2+ influx (3). Moreover, P2X7 receptor affects energy generation in restricted metabolites viability, as fast growing tumors need (4). To investigate the transforming potential conferred by P2X7 receptor to neuroblastoma cells, we took advantage of P2X7 expressing ACN human neuroblastoma cell line that release VEGF in a P2X7 dependent fashion (5). We show here that basal P2X7 receptor expression leads ACN proliferation, while its silencing causes a down-modulation of PI3K /HIF1α/GSK3β pathway. Additionally, proliferation and metabolism modulation can be affected both in vitro and in vivo by pharmacological treatment of ACN cells with P2X7 antagonists AZ10606120 (300nM) and A740003 (5µM). Neuroblastoma growth can be also affected in syngenic in vivo model by treatment of mouse neuroblastoma cells Neuro2a with P2X7 receptor antagonists AZ10606120 (300nM) and A740003 (10µM). These data show that P2X7R plays an important role in neuroblastoma tumor transformation and adaptation to environmental conditions. Thus, we suggest P2X7R as a possible pharmacological target for neuroblastoma treatment. 1. Raffaghello L et al.; Cancer Res. 2006; 66(2):907-14. 2. Gómez-Villafuertes R et al.; FEBS J 2009 ; 276(18):5307-25. 3. Adinolfi E et al.; J Biol Chem. 2009; 284(15):10120-8. 4. Amoroso F et al.; Cell Death Dis. 2012; 3:e370. 5. Adinolfi E et al.; Cancer Res. 2012; 72(12):2957-69.