PO.ET09.03 · 实验与分子治疗
高选择性、强效的可逆共价FGFR4抑制剂BB102通过溶酶体自噬诱导靶蛋白降解
The highly selective and potent reversible-covalent FGFR4 inhibitor, BB102, induces targeted-protein degradation through lysosomal autophagy
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
引言：成纤维细胞生长因子19（FGF19）过表达促成某些形式肝细胞癌（HCC）的肿瘤发生，并且已在横纹肌肉瘤、乳腺癌、结直肠癌和胃癌中发现成纤维细胞生长因子受体4（FGFR4）突变。因此，FGFR4被视为治疗FGF19/FGFR4信号过度激活癌症的新型靶点。我们此前报道BB102是一种高选择性、强效的可逆共价FGFR4抑制剂。在此，我们首次证明BB102不仅抑制FGFR4激酶活性，还通过溶酶体自噬诱导FGFR4降解。
方法：BB102通过基于结构的药物设计研发，并经SAR分析和药物化学迭代优化。采用生化和基于细胞的实验评估BB102的抑制活性。进行了平行人工膜渗透性实验（PAMPA）和MDCK-MDR1细胞系中的渗透性测定。在肿瘤细胞系和小鼠异种移植模型的肿瘤中证明了BB102诱导的FGFR4蛋白降解。
结果：BB102抑制FGFR4激酶活性的IC50为2.5 nM，对所测试的其他206种激酶表现出>400倍的选择性。BB102阻断下游蛋白ERK的磷酸化，IC50为2.4 nM。BB102对同时高表达FGF19和FGFR4或FGFR4突变的肿瘤细胞的细胞增殖表现出强烈的抑制作用，并在小鼠模型中抑制肿瘤生长。PAMPA和MDCK-MDR1细胞系中的渗透性显示BB102可透过血脑屏障（BBB），并在大鼠脑组织中检测到BB102。BB102在FGFR4过表达的HuH-7、Hep3B和SJCRH30癌细胞系中明确诱导FGFR4蛋白降解，且该降解被溶酶体自噬抑制剂Bafilomycin A1所阻断。BB102仅在异种移植小鼠模型的肿瘤中诱导FGFR4降解，而在正常肺和肝中则不然。
结论：BB102是一种FGFR4降解剂，具有高选择性、强效的可逆共价FGFR4激酶抑制作用。BB102在携带HCC肿瘤异种移植的小鼠中具有显著的抗肿瘤活性。它可透过BBB。它在Ia期研究中表现出安全的特征，并在Ib期研究中显示出初步、有前景的疗效。
查看英文原文 English abstract
Introduction: Fibroblast growth factor 19 (FGF19) overexpression contributes to the tumorigenesis of certain forms of hepatocellular carcinoma (HCC) and fibroblast growth factor receptor 4 (FGFR4) mutations have been found in rhabdomyosarcoma, breast, colorectal, and gastric cancer. Thus, FGFR4 is considered as a novel target to treat cancer with hyperactivated FGF19/FGFR4 signaling. We previously reported BB102 was a highly selective and potent reversible-covalent FGFR4 inhibitor. Here we demonstrated for the first time that BB102 not only inhibited FGFR4 kinase activity but also induced FGFR4 degradation through lysosomal autophagy.
Methods: BB102 was developed through structure-based drug design, and optimized by SAR analysis and medicinal chemistry iteration. Biochemical and cell-based assays were applied in evaluation of BB102 inhibitory activity. Parallel artificial membrane permeability assay (PAMPA) and permeability in MDCK-MDR1 cell line were conducted. The degradation of FGFR4 protein induced by BB102 was demonstrated in both tumor cell lines and tumors from xenograft models in mice.
Results: BB102 inhibited FGFR4 kinase activity with IC 50 of 2.5 nM and displayed >400-fold selectivity against the other 206 kinases tested. BB102 blocked the phosphorylation of the downstream protein ERK with IC 50 of 2.4 nM. BB102 exhibited strong inhibitory effects on the cell proliferation with the high expression of both FGF19 and FGFR4, or FGFR4-mutated tumor cells and suppressed tumor growth in mouse models. PAMPA and permeability in MDCK-MDR1 cell line had shown BB102 was permeable to blood-brain barrier (BBB) and BB102 was found in the rat brain tissues. BB102 clearly induced FGFR4 protein degradation in FGFR4 over-expressed HuH-7, Hep3B, and SJCRH30 cancer cell lines, which was blocked by Bafilomycin A1, an inhibitor of lysosomal autophagy. BB102 induced degradation of FGFR4 only in the tumors but not in the normal lungs and livers from xenograft mouse models.
Conclusion: BB102 is a degrader of FGFR4 with highly selective and potent reversible-covalent FGFR4 kinase inhibition. BB102 has remarkable antitumor activity in mice bearing HCC tumor xenografts. It is permeable to BBB. It has shown safe profiles in the phase Ia study and preliminary promising efficacy in the phase Ib study.
利益披露 Disclosure
M. Li, None..
Q. Wang, None..
G. Duan, None..
X. Ma, None..
J. Wang, None..
L. Wei, None..
X. Zhang, None.