Experimental Immunology, and.
Hematology, Amsterdam UMC location University of Amsterdam, Amsterdam, The Netherlands.
Blood. 2022 Aug 11;140(6):630-643. doi: 10.1182/blood.2021013990.
Altered metabolism is a hallmark of both cell division and cancer. Chronic lymphocytic leukemia (CLL) cells circulate between peripheral blood (PB) and lymph nodes (LNs), where they receive proliferative and prosurvival signals from surrounding cells. However, insight into the metabolism of LN CLL and how this may relate to therapeutic response is lacking. To obtain insight into CLL LN metabolism, we applied a 2-tiered strategy. First, we sampled PB from 8 patients at baseline and after 3-month ibrutinib (IBR) treatment, which forces egress of CLL cells from LNs. Second, we applied in vitro B-cell receptor (BCR) or CD40 stimulation to mimic the LN microenvironment and performed metabolomic and transcriptomic analyses. The combined analyses indicated prominent changes in purine, glucose, and glutamate metabolism occurring in the LNs. CD40 signaling mostly regulated amino acid metabolism, tricarboxylic acid cycle (TCA), and energy production. BCR signaling preferably engaged glucose and glycerol metabolism and several biosynthesis routes. Pathway analyses demonstrated opposite effects of in vitro stimulation vs IBR treatment. In agreement, the metabolic regulator MYC and its target genes were induced after BCR/CD40 stimulation and suppressed by IBR. Next, 13C fluxomics performed on CD40/BCR-stimulated cells confirmed a strong contribution of glutamine as fuel for the TCA cycle, whereas glucose was mainly converted into lactate and ribose-5-phosphate. Finally, inhibition of glutamine import with V9302 attenuated CD40/BCR-induced resistance to venetoclax. Together, these data provide insight into crucial metabolic changes driven by the CLL LN microenvironment. The prominent use of amino acids as fuel for the TCA cycle suggests new therapeutic vulnerabilities.
代谢改变是细胞分裂和癌症的共同特征。慢性淋巴细胞白血病（CLL）细胞在循环于外周血（PB）和淋巴结（LNs）之间，在那里它们从周围细胞中接收增殖和生存信号。然而，目前对于 LN CLL 的代谢以及这如何与治疗反应相关的了解还很缺乏。为了深入了解 CLL LN 的代谢，我们采用了两阶段策略。首先，我们在基线时和 3 个月伊布替尼（IBR）治疗后从 8 名患者的 PB 中取样，这迫使 CLL 细胞从 LNs 中迁出。其次，我们应用体外 B 细胞受体（BCR）或 CD40 刺激来模拟 LN 微环境，并进行代谢组学和转录组学分析。联合分析表明，嘌呤、葡萄糖和谷氨酸代谢在 LNs 中发生了明显变化。CD40 信号主要调节氨基酸代谢、三羧酸循环（TCA）和能量产生。BCR 信号优选参与葡萄糖和甘油代谢以及几种生物合成途径。通路分析表明体外刺激与 IBR 治疗的效果相反。一致地，代谢调节剂 MYC 及其靶基因在 BCR/CD40 刺激后被诱导，而被 IBR 抑制。接下来，对 CD40/BCR 刺激的细胞进行的 13C 通量分析证实，谷氨酰胺作为 TCA 循环的燃料具有很强的贡献，而葡萄糖主要转化为乳酸盐和核糖-5-磷酸。最后，用 V9302 抑制谷氨酰胺摄取可减弱 CD40/BCR 诱导的对 venetoclax 的耐药性。总的来说，这些数据提供了对由 CLL LN 微环境驱动的关键代谢变化的深入了解。突出使用氨基酸作为 TCA 循环的燃料表明了新的治疗弱点。
