A small-molecule blocking ribonucleotide reductase holoenzyme formation inhibits cancer cell growth and overcomes drug resistance.
A small-molecule blocking ribonucleotide reductase holoenzyme formation inhibits cancer cell growth and overcomes drug resistance.
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DOI：
10.1158/0008-5472.can-13-1094
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发表时间：
2013-11-01
期刊：
影响因子：
11.2
通讯作者：
Yen Y
中科院分区：
文献类型：
--
作者：
Zhou B;Su L;Hu S;Hu W;Yip ML;Wu J;Gaur S;Smith DL;Yuan YC;Synold TW;Horne D;Yen Y
核糖核苷酸还原酶（RNR）是一个有吸引力的抗癌药物的目标，因为它在DNA合成，生长，转移和癌细胞的耐药性的中心功能。目前临床上已建立的RNR抑制剂存在半衰期短、耐药性、铁螯合等缺点。在这里，我们报告了一类新的有效的RNR抑制剂解决这些问题的发展。通过计算机模拟，提出了一个新的配体结合口袋的RNR小亚基（RRM 2）的C-末端尾部附近，并通过定点突变和NMR技术验证。通过虚拟筛选NCI多样性小分子数据库来鉴定靶向该口袋的化合物。通过先导优化，我们开发了新型RNR抑制剂COH 29，其作为重组和细胞人类RNR酶的有效抑制剂。C 0 H 29克服癌细胞中的羟基脲和吉西他滨抗性。它有效地抑制了NCI 60人类癌症组中大多数细胞系的增殖，最显著的是卵巢癌和白血病，但对正常成纤维细胞或内皮细胞几乎没有影响。在人类癌症的小鼠异种移植模型中，与媒介物相比，C 0 H 29治疗减少了肿瘤生长。定点诱变、NMR和表面等离子体共振生物传感器研究证实了COH 29与所提出的配体结合口袋的结合，并为RRM 1-RRM 2四级结构的组装阻断提供了证据。我们的研究结果提供了COH 29作为一类有前途的新型RNR抑制剂的临床前验证，具有新的抑制机制，具有改善人类癌症治疗的广泛潜力。
Ribonucleotide reductase (RNR) is an attractive target for anticancer agents given its central function in DNA synthesis, growth, metastasis, and drug resistance of cancer cells. The current clinically established RNR inhibitors have the shortcomings of short halflife, drug resistance, and iron chelation. Here we report the development of a novel class of effective RNR inhibitors addressing these issues. A novel ligand-binding pocket on the RNR small subunit (RRM2) near the C-terminal tail was proposed by computer modeling and verified by site-directed mutagenesis and NMR techniques. A compound targeting this pocket was identified by virtual screening of the NCI diverse small molecule database. By lead optimization we developed the novel RNR inhibitor COH29 which acted as a potent inhibitor of both recombinant and cellular human RNR enzymes. COH29 overcame hydroxyurea and gemcitabine resistance in cancer cells. It effectively inhibited proliferation of most cell lines in the NCI 60 human cancer panel, most notably ovarian cancer and leukemia, but exerted little effect on normal fibroblasts or endothelial cells. In mouse xenograft models of human cancer, COH29 treatment reduced tumor growth compared to vehicle. Site-directed mutagenesis, NMR and surface plasmon resonance biosensor studies confirmed COH29 binding to the proposed ligand-binding pocket and offered evidence for assembly blockade of the RRM1-RRM2 quaternary structure. Our findings offer preclinical validation of COH29 as a promising new class of RNR inhibitors with a new mechanism of inhibition, with broad potential for improved treatment of human cancer.