Identification of Small Molecule Inhibitors of QSOX1

抑制QSOX 1的小分子的鉴定 项目摘要 Quiescin Sulfhydryl Oxidase 1（QSOX 1）酶在多种类型的肿瘤中过量产生 包括胰腺、乳腺、肾脏、肺和前列腺。QSOX 1穿梭蛋白质中的二硫键， 它们在内质网和高尔基体中折叠。它在细胞外基质（ECM）中特别活跃， 通过帮助折叠参与粘附的蛋白质（层粘连蛋白）和基质，在肿瘤细胞侵袭中发挥作用 金属蛋白酶我们首先通过基因沉默其表达（shRNA）来靶向QSOX 1， 抑制肿瘤的生长、侵袭和转移。这导致了一个假设， 小分子也可能抑制该酶，导致类似的抗肿瘤活性。 高通量筛选鉴定了几种抑制酶促降解的化合物。 QSOX 1的活动。第一个报道的化合物是依布硒啉，一种含硒分子， 显示与QSOX 1上的Cys-165和Cys-237共价结合。荷人肿瘤小鼠的治疗 具有依布硒啉的异种移植物显示与具有依布硒啉的异种移植物相比， 对照尽管依布硒啉具有活性并抑制QSOX 1，但它在某种程度上是非特异性的， 其他酵素 第二种化合物SBI-183，i）在无细胞测定中抑制QSOX 1的酶活性， ii）以20 μ M的Kd与QSOX 1结合，和iii）在体外抑制肿瘤细胞侵袭和转移， 在人肿瘤异种移植模型中。小鼠中的最大耐受剂量（MTD）研究为> 200 mg/kg， 心脏、肺、肾和肝等重要器官均无病变。的抗肿瘤活性 SBI-183表明，鉴定SBI-183的更有效的类似物可能有助于开发 针对QSOX 1的抗肿瘤/转移化合物作为新的靶点。第一阶段SBIR提案将 采用药物化学技术，使用筛选漏斗筛选SBI-183的类似物， 包括i）QSOX 1酶抑制测定，ii）结合测定和iii）体外肿瘤细胞侵袭测定。 将确定三到五种类似物，它们将在人类异种移植模型中进行测试， 第二阶段项目，包括吸附、分布、代谢、排泄和毒性（ADMET）研究。

Identification of Small Molecules that inhibit QSOX1 Project Summary The Quiescin Sulfhydryl Oxidase 1 (QSOX1) enzyme is over-produced by multiple types of tumors including pancreas, breast, kidney, lung and prostate. QSOX1 shuttles disulfide bonds in proteins while they are folding in the ER and Golgi. It is especially active in the extracellular matrix (ECM) where it plays a role in tumor cell invasion by helping to fold proteins involved in adherence (laminin) and matrix metalloproteinases. We first targeted QSOX1 by genetically silencing its expression (shRNA) which suppressed tumor growth, invasion and metastasis in vitro and in vivo. This led to the hypothesis that small molecules might also inhibit the enzyme resulting in similar anti-tumor activities. High throughput screening identified several chemical compounds that inhibit the enzymatic activity of QSOX1. The first reported compound was ebselen, a selenium-containing molecule that was shown to covalently bind to Cys-165 and Cys-237 on QSOX1. Treatment of mice bearing human tumor xenografts with ebselen demonstrated suppression of tumor cell growth and invasion compared to controls. Although ebselen was active and inhibited QSOX1, it is somewhat non-specific and also inhibits other enzymes. The second compound, SBI-183, i) inhibits the enzymatic activity of QSOX1 in a cell free assay, ii) binds to QSOX1 with a Kd of 20uM and iii) suppresses tumor cell invasion and metastasis in vitro and in a human tumor xenograft model. Maximal tolerated dose (MTD) studies in mice were >200mg/kg and revealed no pathology in vital organs such as heart, lungs, kidney, and liver. The anti-tumor activity of SBI-183 suggests that identifying more potent analogs of SBI-183 may be useful in the development of anti-tumor/metastatic compounds against QSOX1 as a novel target. This phase I SBIR proposal will employ medicinal chemistry techniques to screen analogs of SBI-183 using a screening funnel that includes i) QSOX1 enzyme inhibition assays, ii) binding assays and iii) in vitro tumor cell invasion assays. Three to five analogs will be identified that will move forward for testing in human xenograft models in a phase II project that includes adsorption, distribution, metabolism, excretion and toxicity (ADMET) studies.