神经母细胞瘤是儿童常见的恶性实体肿瘤。 其中，MYCN扩增的神经母细胞瘤恶性程度极高，治疗效果和预后差，尚无有效的靶向药物。 因此，深入研究此类肿瘤的病理机制以期找到有效的治疗手段至关重要。 申请人前期证明MYCN扩增的神经母细胞瘤细胞高度依赖谷氨酰胺存活，而且发现谷氨酰胺酶2(GLS2)在这类肿瘤中过表达。体外抑制GLS2显著诱导MYCN扩增的神经母细胞瘤细胞死亡。然而，GLS2在此类肿瘤中的调控机制和生物学功能尚不明确。据此，拟采用分子细胞生物学、代谢组学和模式动物等学科交叉的研究方法，深入研究(1) N-Myc激活GLS2的分子机制；(2) GLS2对谷氨酰胺代谢和化疗抵抗的影响；(3) GLS2对神经母细胞瘤在体内发生发展的影响。该项目的实施有望揭示GLS2表达调控的新机制，为MYCN扩增的神经母细胞瘤的治疗提供潜在的治疗靶点。

Neuroblastoma is one of the most frequent solid tumors in infants and children. Amplification of the MYCN oncogene in human neuroblastoma predicts poor prognosis and resistance to therapy. Therefore, a complete understanding of the pathogenic mechanisms responsible for this type of cancer is of great emergence. In this regard, we previously showed that MYCN-amplified neuroblastoma cells constantly require large amounts of glutamine to sustain their viability. However, how MYCN-amplified neuroblastoma cells utilize glutamine metabolism to support unabated growth remains unclear thus far. To this end, we identified expression of glutaminase 2 (GLS2), a critical enzyme involved in the first step in glutaminolysis, was significantly elevated in MYCN-amplified neuroblastomas in comparison with non-amplified ones. Inhibition of GLS2 activity induced significant cell death, suggesting GLS2-mediated glutaminolysis is essential for MYCN-amplified neuroblastoma cells. Combining approaches of molecular cell biology, metabolomics and animal modeling, we aim to (1) investigate molecular mechanisms whereby N-Myc activates GLS2 expression; (2) examine how GLS2 affects TCA cycle metabolites and chemoresistance; and (3) evaluate the in-vivo pathogenic roles of GLS2 in MYCN-transgenic neuroblastoma tumor model. Our studies will decipher novel mechanisms by which N-Myc regulates glutamine metabolism through direct GLS2 activation. More importantly, these results also provide strong rationales for developing highly specific small-molecule inhibitors against GLS2 in treating MYCN-amplified neuroblastomas, which are resistant to routine chemotherapies.