Aminopeptidase N (APN), also known as CD13 antigen or membrane alanyl aminopeptidase, belongs to the M1 family of the MA clan of zinc metallopeptidases. In cancer cells, the inhibition of aminopeptidases including APN causes the phenomenon termed the amino acid deprivation response (AADR), a stress response characterized by the upregulation of amino acid transporters and synthetic enzymes and activation of stress-related pathways such as nuclear factor kB (NFkB) and other pro-apoptotic regulators, which leads to cancer cell death by apoptosis. Recently, APN inhibition has been shown to augment DR4-induced tumor cell death and thus overcome resistance to cancer treatment with DR4-ligand TRAIL, which is available as a recombinant soluble form dulanermin. This implies that APN inhibitors could serve as potential weapons for overcoming cancer treatment resistance. In this study, a series of basically substituted acetamidophenones and the semicarbazones and thiosemicarbazones derived from them were prepared, for which APN inhibitory activity was determined. In addition, a selective anti-proliferative activity against cancer cells expressing APN was demonstrated. Our semicarbazones and thiosemicarbazones are the first compounds of these structural types of Schiff bases that were reported to inhibit not only a zinc-dependent aminopeptidase of the M1 family but also a metalloenzyme.
氨基肽酶 N(APN)又称 CD13 抗原或膜丙氨酰氨基肽酶,属于锌金属肽酶 MA 家族的 M1 族。在癌细胞中,抑制包括 APN 在内的氨肽酶会导致一种被称为氨基酸剥夺反应(AADR)的现象,这种应激反应的特点是氨基酸转运体和合成酶的上调以及核因子 kB(NFkB)和其他促凋亡调节因子等应激相关途径的激活,从而导致癌细胞凋亡。最近的研究表明,APN 抑制剂可增强 DR4 诱导的肿瘤细胞死亡,从而克服 DR4 配体 TRAIL 对癌症治疗的抗药性。这意味着 APN 抑制剂可作为克服癌症治疗耐药性的潜在武器。本研究制备了一系列基本取代的苯乙脒及其衍生的半咔唑酮和硫代咔唑酮,并测定了它们的 APN 抑制活性。此外,还证明了它们对表达 APN 的癌细胞具有选择性抗增殖活性。据报道,我们的半咔唑酮和硫代氨基咔唑酮是这些结构类型的希夫碱化合物中第一个不仅能抑制 M1 家族的锌依赖性氨肽酶,还能抑制金属酶的化合物。