Hypoxia-inducible factor 1 (HIF-1) is a promising drug target for cancer chemotherapy. In our screening program aimed at identifying new HIF-1 inhibitors by using a hypoxia-responsive luciferase reporter gene assay, KUSC-5001 containing the 1-alkyl-1H-pyrazole-3-carboxamide moiety was found as a potential hit molecule. During an extensive structure-activity relationship (SAR) study, we developed a more effective HIF-1 inhibitor KUSC-5037 (IC₅₀=1.2 μM). Under hypoxic conditions, KUSC-5037 suppressed the HIF-1α (regulatory subunit of HIF-1) mRNA, causing decreases in the gene expression of HIF-1 target genes such as carbonic anhydrase 9 (CA9) and vascular endothelial growth factor (VEGF) genes. Furthermore, by applying our fluorescent and bifunctional probes, ATP5B, a catalytic β subunit of mitochondrial F_oF₁-ATP synthase, was identified as a target protein of KUSC-5037. These results indicate that the derivatives of KUSC-5037 containing the 1-alkyl-1H-pyrazole-3-carboxamide moiety are promising lead molecules for the inhibition of HIF-1 signaling via F_oF₁-ATP synthase suppression.

缺氧诱导因子 1 (HIF-1) 是一种有前景的癌症化疗药物靶点。在我们旨在通过使用缺氧反应性荧光素酶报告基因检测鉴定新的 HIF-1 抑制剂的筛选计划中，发现含有 1-烷基-1 H-吡唑-3-甲酰胺部分的KUSC-5001作为潜在的命中分子。在广泛的构效关系 (SAR) 研究中，我们开发了一种更有效的 HIF-1 抑制剂KUSC-5037 (IC ₅₀ =1.2 μM)。在缺氧条件下，KUSC-5037抑制 HIF-1α（HIF-1 的调节亚基）mRNA，导致 HIF-1 靶基因如碳酸酐酶 9（CA9）和血管内皮生长因子的基因表达降低。VEGF ) 基因。此外，通过应用我们的荧光和双功能探针，线粒体 F _o F ₁ -ATP 合酶的催化 β 亚基ATP5B被鉴定为KUSC-5037的靶蛋白。这些结果表明，KUSC-5037的衍生物含有 1-烷基-1 H-吡唑-3-甲酰胺部分，是通过 F _o F ₁ -ATP 合酶抑制抑制 HIF-1 信号传导的有前途的先导分子。