State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, #345 Lingling Rd., Shanghai, 200032, China; University of Chinese Academy of Sciences, Beijing, 100049, China; School of Molecular Medicine, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310013, China.
State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, #345 Lingling Rd., Shanghai, 200032, China.
Eur J Med Chem. 2024 Apr 5;269:116310. doi: 10.1016/j.ejmech.2024.116310. Epub 2024 Mar 5.
Hematopoietic progenitor kinase 1 (HPK1) is a negative regulator of T-cell receptor signaling. While HPK1 is considered as a promising target for cancer immunotherapy, no small-molecule HPK1 inhibitors have been approved for cancer treatment. Herein, we report the discovery of a series of new HPK1 inhibitors with a 5-aminopyrido[2,3-d]pyrimidin-7(8H)-one scaffold. The most potent compound 9f inhibited HPK1 kinase activity with an IC of 0.32 nM in the time-resolved fluorescence resonance energy transfer (TR-FRET) assays, while displayed reasonable selectivity in a panel of 416 kinases. Cellular engagement of HPK1 by compound 9f was confirmed through the nano-bioluminescence resonance energy transfer (Nano-BRET) experiments. Compound 9f effectively reduced the phosphorylation of the downstream protein SLP-76 in primary peripheral blood mononuclear cells (PBMCs) and human T lymphocytic leukemia Jurkat cells. Compound 9f also enhanced the IL-2 and IFN-γ secretion in PBMCs. Furthermore, the binding mode of compound 9f with HPK1 was confirmed by the resolved cocrystal structure. Taken together, this study provides HPK1 inhibitors with a novel scaffold and clear binding mode for further development of HPK1-targeted therapeutic agents.
造血祖细胞激酶 1（HPK1）是 T 细胞受体信号的负调节剂。虽然 HPK1 被认为是癌症免疫治疗的一个有前途的靶点，但尚无小分子 HPK1 抑制剂被批准用于癌症治疗。在此，我们报告了一系列具有 5-氨基吡啶并[2,3-d]嘧啶-7(8H)-酮骨架的新型 HPK1 抑制剂的发现。最有效的化合物 9f 在时间分辨荧光共振能量转移（TR-FRET）测定中以 0.32 nM 的 IC 抑制 HPK1 激酶活性，而在 416 种激酶的面板中显示出合理的选择性。通过纳米生物发光共振能量转移（Nano-BRET）实验证实了化合物 9f 与 HPK1 的细胞结合。化合物 9f 可有效降低原代外周血单核细胞（PBMC）和人 T 淋巴细胞白血病 Jurkat 细胞中 SLP-76 下游蛋白的磷酸化。化合物 9f 还增强了 PBMC 中 IL-2 和 IFN-γ 的分泌。此外，通过解析的共晶结构证实了化合物 9f 与 HPK1 的结合模式。总之，这项研究为 HPK1 靶向治疗剂的进一步开发提供了具有新型骨架和明确结合模式的 HPK1 抑制剂。
