Targeting Glutaminolysis Shows Efficacy in Both Prednisolone-Sensitive and in Metabolically Rewired Prednisolone-Resistant B-Cell Childhood Acute Lymphoblastic Leukaemia Cells

In spite of the considerable progress in risk stratification and therapeutic regimens in childhood acute lymphoblastic leukaemia (cALL), which has led to cure rates of above 90%, prognosis for patients with relapsed disease remains poor. The main cause of therapy failure is drug resistance, most commonly to glucocorticoids (GCs). While alterations of cell metabolism in cALL are considered a hallmark of this malignancy as well, the molecular differences between prednisolone sensitive and resistant lymphoblasts are not well-studied, thereby precluding the development of novel and targeted therapies. Therefore, the aim of this work was to investigate the biology of matched pairs of cell lines where GCs are effective and such with acquired lack of response to prednisolone. In order to address this, we took advantage of the molecular characterisation of an in vitro model of GC resistance we had previously developed. An integrated transcriptomic and metabolomic analysis revealed alterations in oxidative phosphorylation, glycolysis, amino acid, pyruvate and nucleotide biosynthesis, as well as activation of mTORC1 and MYC signaling, which are also known to control cell metabolism. In attempt to explore the potential therapeutic effect of inhibiting one of the hits from our analysis, we targeted the glutamine-glutamate-α-ketoglutarate axis by three different strategies, all of which impaired mitochondrial respiration and ATP production and induced apoptosis in both GC-sensitive and resistant cell lines. In summary, we report that prednisolone resistance may be accompanied by considerable rewiring of transcriptional and biosynthesis programs. We suggest that targeting glutamine metabolism presents a novel therapeutic approach in cALL. Comparing biological triplicates of prednisolone sensitive (Sup-B15) and resistant (Sup-PR) childhood acute lymphoblastic leukaemia cells.

尽管儿童急性淋巴细胞白血病（childhood acute lymphoblastic leukaemia, cALL）的风险分层与治疗方案已取得显著进展，治愈率已突破90%，但复发患者的预后仍然不佳。治疗失败的主要原因是耐药性，其中最常见的是糖皮质激素（glucocorticoids, GCs）耐药。尽管儿童急性淋巴细胞白血病的细胞代谢异常被认为是该恶性肿瘤的标志性特征之一，但泼尼松（prednisolone）敏感与耐药淋巴母细胞之间的分子差异尚未得到充分研究，这阻碍了新型靶向治疗方案的开发。因此，本研究旨在探究两组匹配细胞系的生物学特性：一组为糖皮质激素敏感型细胞系，另一组为获得性泼尼松耐药细胞系。为此，我们利用此前构建的糖皮质激素耐药体外模型的分子表征数据开展研究。整合转录组与代谢组学分析发现，氧化磷酸化、糖酵解、氨基酸代谢、丙酮酸代谢及核苷酸生物合成通路均发生异常，同时mTORC1与MYC信号通路被激活——这两条通路已知可调控细胞代谢。为探究本研究筛选得到的靶点之一的抑制潜力，我们通过三种不同策略靶向谷氨酰胺-谷氨酸-α-酮戊二酸轴，结果显示该干预可同时损伤糖皮质激素敏感与耐药细胞系的线粒体呼吸与ATP生成，并诱导细胞凋亡。综上，本研究表明泼尼松耐药可能伴随转录程序与生物合成程序的显著重编程。我们提出，靶向谷氨酰胺代谢可为儿童急性淋巴细胞白血病提供全新的治疗策略。本研究对泼尼松敏感（Sup-B15）与耐药（Sup-PR）儿童急性淋巴细胞白血病细胞的3组生物学重复样本进行了比较分析。