The targeted regulation of LSD1, which is highly expressed in a variety of tumor cells, is a promising cancer therapy strategy. Several LSD1 inhibitors are currently under clinical evaluation, and most of these inhibitors are irreversible. Here, we report the design, synthesis and biochemical evaluation of novel tetrahydroquinoline-based reversible LSD1 inhibitors. Compounds 18s and 18x, which are selective to LSD1 over MAO-A/B, exhibit excellent LSD1 inhibition at the molecular levels with IC₅₀ = 55 nM and 540 nM, respectively. The classic Lineweaver–Burk plots revealed that compound 18s could reversibly bind the LSD1 enzyme in a noncompetitive manner. Molecular docking was used to reveal the potential binding-mode of the compounds and interpret the structure-activity relationships. Furthermore, compounds 18s and 18x significantly inhibited proliferation (IC₅₀ = 1.13 μM and 1.15 μM, respectively) and induced apoptosis in MGC-803 cells with high expression of LSD1. Compound 18x showed acceptable liver microsomal stability. Meanwhile, 18x did not appear to inhibit CYPs at 10 μM in vitro. Remarkably, the oral administration of compound 18x can inhibit the growth of MGC-803 xenograft tumors without significant side effects. Our findings suggest that tetrahydroquinoline-based LSD1 inhibitors deserve further investigation for the treatment of LSD1 overexpressing cancer.

在多种肿瘤细胞中高度表达的LSD1的靶向调节是一种有前途的癌症治疗策略。几种LSD1抑制剂目前正在临床评估中，并且大多数这些抑制剂是不可逆的。在这里，我们报告基于新型四氢喹啉可逆LSD1抑制剂的设计，合成和生化评估。在MAO-A / B上对LSD1具有选择性的化合物18s和18x在分子水平上 分别表现出优异的LSD1抑制作用，IC ₅₀ = 55 nM和540 nM。经典的Lineweaver–Burk图显示复合18s可能以非竞争性方式可逆地结合LSD1酶。分子对接用于揭示化合物的潜在结合方式并解释结构-活性关系。此外，化合物的18s和18倍显著抑制增殖（IC ₅₀  = 1.13  μ M和1.15  μ分别用M，）和诱导细胞凋亡在MGC-803细胞与LSD1的高表达。化合物18x显示出可接受的肝微粒体稳定性。同时，18X没有出现在10〜抑制的CYP  μ中号体外。值得注意的是，口服化合物18x可以抑制MGC-803异种移植肿瘤的生长，而没有明显的副作用。我们的发现表明，基于四氢喹啉的LSD1抑制剂对于LSD1过表达的癌症的治疗值得进一步研究。