Halting the FGF/FGFR axis leads to anti-tumor activity in Waldenström’s Macroglobulinemia by silencing MYD88. Halting the FGF/FGFR axis leads to anti-tumor activity in Waldenström’s Macroglobulinemia by silencing MYD88

The human fibroblast growth factor/fibroblast growth factor-receptor (FGF/FGFR) axis deregulation is largely involved in supporting the pathogenesis of hematologic malignancies, including Waldenström’s Macroglobulinemia (WM). WM is still an incurable disease, and patients succumb due to disease progression. Therefore, novel therapeutics designed to specifically target deregulated signaling pathways in WM are required. We aimed to investigate the role of FGF/FGFR blocking system in WM by using a pan-FGF trap molecule (NSC12). Wide-transcriptome profiling confirmed inhibition of FGFR-signaling in NSC12-treated WM cells; unveiling a significant inhibition of Myd88 also confirmed at protein level. Importantly, the NSC12-dependent silencing of Myd88 was functionally active, as it led to inhibition of Myd88-driven pathways, such as BTK and SYK, as well as the Myd88-downstream target HCK. Of note, both canonical and non-canonical NFB cascades were down-regulated in WM cells upon NSC12 treatment. Functional sequelae exerted by NSC12 in WM cells were studied, demonstrating significant inhibition of WM cell growth, induction of WM cell apoptosis, halting MAPK, JAK/STAT3 and PI3K-Akt pathways. Importantly, NSC12 exerted an anti-WM effect even in the presence of bone marrow microenvironment, both in vitro and in vivo. Our studies provide the evidence for using NSC12 as a specific FGF/FGFR system inhibitor, thus representing a novel therapeutic strategy in WM. Overall design: BCWM.1 and MWCL.1 cell lines were analyzed after treatment with NSC12 (6µM) for 12 hours in comparison to untreated cells. All experiments were performed in triplicates for each condition.

人成纤维细胞生长因子（fibroblast growth factor, FGF）/成纤维细胞生长因子受体（fibroblast growth factor receptor, FGFR）信号轴失调，在包括华氏巨球蛋白血症（Waldenström’s Macroglobulinemia, WM）在内的血液系统恶性肿瘤的发病机制中发挥关键推动作用。华氏巨球蛋白血症目前仍为不可治愈的疾病，患者多因疾病进展而死亡，因此亟需开发能够特异性靶向WM中失调信号通路的新型治疗手段。本研究旨在利用泛FGF捕获分子（pan-FGF trap molecule）NSC12，探究FGF/FGFR阻断系统在WM中的功能。全转录组表达谱分析证实，经NSC12处理的WM细胞中FGFR信号通路受到抑制；同时发现髓系分化因子88（Myd88）的表达显著下调，且该现象在蛋白水平得到验证。值得注意的是，NSC12介导的Myd88沉默具有功能活性，可抑制Myd88下游调控的信号通路，包括布鲁顿酪氨酸激酶（Bruton's tyrosine kinase, BTK）、脾酪氨酸激酶（Spleen tyrosine kinase, SYK）以及Myd88下游靶基因造血细胞激酶（Hemopoietic cell kinase, HCK）。此外，经NSC12处理后，WM细胞中的经典与非经典NF-κB（nuclear factor kappa-B, NF-κB）信号级联反应均受到下调。本研究还探究了NSC12对WM细胞产生的功能效应，结果显示其可显著抑制WM细胞增殖、诱导细胞凋亡，并阻断丝裂原活化蛋白激酶（mitogen-activated protein kinase, MAPK）、Janus激酶/信号转导与转录激活子3（Janus kinase/signal transducer and activator of transcription 3, JAK/STAT3）及磷脂酰肌醇3-激酶-蛋白激酶B（phosphatidylinositol 3-kinase-Akt, PI3K-Akt）信号通路。尤为重要的是，无论在体外还是体内实验中，即便存在骨髓微环境，NSC12仍可发挥抗WM效应。本研究证实，NSC12可作为特异性FGF/FGFR系统抑制剂，为WM的治疗提供了全新的策略。实验整体设计：将BCWM.1与MWCL.1细胞系分别用6µM的NSC12处理12小时，以未处理细胞作为对照进行分析；所有实验均设置3次生物学重复。