Substrate-Dependence of Competitive Nucleotide Pyrophosphatase/Phosphodiesterase1 (NPP1) Inhibitors.
Substrate-Dependence of Competitive Nucleotide Pyrophosphatase/Phosphodiesterase1 (NPP1) Inhibitors.
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DOI：
10.3389/fphar.2017.00054
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发表时间：
2017
影响因子：
5.6
通讯作者：
Müller CE
中科院分区：
文献类型：
--
作者：
Lee SY;Sarkar S;Bhattarai S;Namasivayam V;De Jonghe S;Stephan H;Herdewijn P;El-Tayeb A;Müller CE
核苷酸焦磷酸酶/磷酸二酯酶1型（NPP1）是一种参与胞外核苷酸水解的膜糖蛋白。它的主要底物是ATP，转化为AMP和二磷酸。NPP1被认为是脑癌和免疫肿瘤治疗的新靶点。目前已经报道了几种NPP1抑制剂，其中大多数与人工底物对硝基苯基5′-胸苷单磷酸（p-Nph-5′-TMP）进行了比较。最近，我们观察到一类竞争性NPP1抑制剂与人工底物p-Nph-5′-TMP相比，与天然底物ATP相比，在抑制能力上存在很大差异。因此，本研究的目的是研究人类NPP1抑制剂是否普遍表现出底物依赖的抑制效力。对核苷酸和非核苷酸NPP1抑制剂的系统评估显示，与ATP相比，竞争性NPP1抑制剂的测定Ki值有显著差异，但与常用的人工底物p-Nph-5′- tmp相比，非竞争性和非竞争性抑制剂的测定Ki值没有显著差异。p-Nph-5′-TMP对NPP1的变构调节可能解释了这些差异。使用AMP衍生物对硝基苯基5′-腺苷单磷酸（p-Nph-5′-AMP）作为替代人工底物获得的结果与使用天然底物ATP的结果相关性更好。
Nucleotide pyrophosphatase/phosphodiesterase type 1 (NPP1) is a membrane glycoprotein involved in the hydrolysis of extracellular nucleotides. Its major substrate is ATP which is converted to AMP and diphosphate. NPP1 was proposed as a new therapeutic target in brain cancer and immuno-oncology. Several NPP1 inhibitors have been reported to date, most of which were evaluated vs. the artificial substrate p-nitrophenyl 5′-thymidine monophosphate (p-Nph-5′-TMP). Recently, we observed large discrepancies in inhibitory potencies for a class of competitive NPP1 inhibitors when tested vs. the artificial substrate p-Nph-5′-TMP as compared to the natural substrate ATP. Therefore, the goal of the present study was to investigate whether inhibitors of human NPP1 generally display substrate-dependent inhibitory potency. Systematic evaluation of nucleotidic as well as non-nucleotidic NPP1 inhibitors revealed significant differences in determined Ki values for competitive, but not for non- and un-competitive inhibitors when tested vs. the frequently used artificial substrate p-Nph-5′-TMP as compared to ATP. Allosteric modulation of NPP1 by p-Nph-5′-TMP may explain these discrepancies. Results obtained using the AMP derivative p-nitrophenyl 5′-adenosine monophosphate (p-Nph-5′-AMP) as an alternative artificial substrate correlated much better with those employing the natural substrate ATP.