Abstract 2041: Development and analysis of mouse brain tumor models derived from neural stem cells expressing activated ALK

Abstract

Abstract Neural Stem Cells (NSCs), having self-renewal and multipotent ability, are considered one of the cells-of-origin of glioblastoma maltifome (GBM). Although NSCs can be enriched in neurosphere floating culture with serum-free media containing EGF/FGF as a classical method, neurosphere is composed of not only NSCs but also differentiated and apoptotic cells. Therefore, we utilize the method for efficient derivation of NSCs with long-term self-renewal and differentiate capacity in adherent culture. Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase first identified in a chromosomal translocation associated with anaplastic large cell lymphomas. Subsequently, new ALK translocations were found in a fraction of non-small-cell lung cancers and in other solid tumors. The function of full-length ALK is involved in neuronal cell differentiation, regeneration and synapse formation. Recently, gene amplification and mutations of full-length ALK were identified in neuroblastoma. Furthermore, it is reported that ALK and PTN, ligand of ALK, are required for maintenance of the stem cell population in GBM. Although constitutive activation of ALK signaling results in cell transformation, little is known about the tumorigenic mechanisms induced by activated ALK. We reasoned that ALK activity has a crucial role in GBM. To verify this hypothesis, human GBM stem cell lines were treated with crizotinib, ALK inhibitor. Crizotinib could suppress the proliferation of human GBM stem cell lines in dose-dependent-manner. Next, we have established a stable mouse model of brain tumor transplanting the genetically modified NSCs. Active mutant of H-RAS could transform the Ink4a/Arf KO NSCs but not WT NSCs. However, transplanting of WT NSCs transduced activated ALK could rapidly formed highly proliferative and invasive brain tumors. Histological characteristics of these tumors resembled human GBM phenotype demonstrating necrosis, perivascular cuffing and giant cell formation. Although the activated H-RAS increased expression of Ink4a in WT NSCs, but the activated ALK never changed. On the basis of these findings, we propose a specific regulation against tumor suppressor genes by activated ALK. Citation Format: Nobuyuki Onishi, Oltea Sampetrean, Eiji Sugihara, Hideyuki Saya. Development and analysis of mouse brain tumor models derived from neural stem cells expressing activated ALK. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2041. doi:10.1158/1538-7445.AM2014-2041