Department of Biochemistry, Chronic Diseases Program, Regional Protein Chemistry Center, Ottawa Hospital Research Institute, University of Ottowa, Ottawa, Canada.
PLoS One. 2009 Nov 26;4(11):e7700. doi: 10.1371/journal.pone.0007700.
Furin represents a crucial member of secretory mammalian subtilase, the Proprotein Convertase (PC) or Proprotein Convertase Subtilisin/Kexin (PCSK) superfamily. It has been linked to cancer, tumorgenesis, viral and bacterial pathogenesis. As a result it is considered a major target for intervention of these diseases.
METHODOLOGY/PRINCIPAL FINDINGS: Herein, we report, for the first time, the synthesis and biological evaluation of a newly designed potent furin inhibitor that contains a highly reactive beta-turn inducing and radical generating "enediynyl amino acid" (Eda) moiety. "Eda" was inserted between P1 and P1' residues of hfurin(98-112) peptide, derived from the primary cleavage site of furin's own prodomain. The resulting hexadecapeptide derivative inhibited furin in vitro with IC(50) approximately 40 nM when measured against the fluorogenic substrate Boc-RVRR-MCA. It also inhibited furin-mediated cleavage of a fluorogenic peptide derived from hSARS-CoV spike protein with IC(50) approximately 193 nM. Additionally it also blocked furin-processing of growth factors proPDGF-A, B and VEGF-C that are linked to tumor genesis and cancer. Circular dichroism study showed that this inhibitor displayed a predominantly beta-turn structure while western blots confirmed its ability to protect furin protein from self degradation.
CONCLUSION/SIGNIFICANCE: These findings imply its potential as a therapeutic agent for intervention of cancer and other furin-associated diseases.
弗林蛋白酶是哺乳动物分泌性内切蛋白酶（脯氨酸转换酶或脯氨酸转换酶枯草溶菌素/柯萨奇蛋白酶）超家族中的关键成员。它与癌症、肿瘤发生、病毒和细菌发病机制有关。因此，它被认为是干预这些疾病的主要靶点。
方法/主要发现：本文首次报道了一种新设计的强效弗林蛋白酶抑制剂的合成和生物学评价，该抑制剂含有一个高度反应性的β-转角诱导和自由基生成的“烯二炔基氨基酸”（Eda）部分。“Eda”插入弗林蛋白酶自身前肽的主要切割位点衍生的 hfurin（98-112）肽的 P1 和 P1'残基之间。所得的十六肽衍生物在体外对荧光底物 Boc-RVRR-MCA 的抑制活性的 IC50 约为 40 nM。它还抑制了弗林蛋白酶介导的 hSARS-CoV 刺突蛋白衍生的荧光肽的切割，IC50 约为 193 nM。此外，它还阻断了与肿瘤发生和癌症相关的生长因子 proPDGF-A、B 和 VEGF-C 的弗林蛋白酶加工。圆二色性研究表明，该抑制剂显示出主要的β-转角结构，而 Western blot 证实了它保护弗林蛋白酶蛋白免受自身降解的能力。
结论/意义：这些发现表明，它有可能成为干预癌症和其他与弗林蛋白酶相关疾病的治疗剂。
