The enzyme inosine 5′-monophosphate dehydrogenase (IMPDH) catalyzes an essential step in the de novo biosynthesis of guanine nucleotides, and thus regulates the guanine nucleotide pool required for cell proliferation. Of the two isoforms, human IMPDH type 2 (hIMPDH2) is a validated molecular target for potential immunosuppressive, antiviral and anticancer chemotherapy. In search of newer hIMPDH2 inhibitors as potential anticancer agents, three novel series (A: 5-aminoisobenzofuran-1(3H)-one, B: 3,4-dimethoxyaniline and C: benzo[d]-[1,3]dioxol-5-ylmethanamine) were synthesized and evaluated for in vitro and cell-based activities. A total of 37 molecules (29–65) were screened for their in vitro hIMPDH2 inhibition, with particular emphasis on establishing their structure–activity relationship (SAR) trends. Eight compounds (hits, 30, 31, 33–35, 37, 41 and 43) demonstrated significant enzyme inhibition (>70% @ 10 μM); especially the A series molecules were more potent than B series (<70% inhibition @ 10 μM), while C series members were found to be inactive. The hIMPDH2 IC₅₀ values for the hits ranged from 0.36 to 7.38 μM. The hits displaying >80% hIMPDH2 inhibition (30, 33, 35, 41 and 43) were further assessed for their cytotoxic activity against cancer cell lines such as MDA-MB-231 (breast adenocarcinoma), DU145 (prostate carcinoma), U87 MG (glioblastoma astrocytoma) and a normal cell line, NIH-3T3 (mouse embryonic fibroblast) using MTT assay. Most of the compounds exhibited higher cellular potency against cancer cell lines and notably lower toxicity towards NIH-3T3 cells compared to mycophenolic acid (MPA), a prototypical hIMPDH2 inhibitor. Two of the series A hits (30 and 35) were evaluated in human peripheral blood mononuclear cells (hPBMC) assay and found to be better tolerated than MPA. The calculated/predicted molecular and physicochemical properties were satisfactory with reference to drug-likeness. The molecular docking studies clearly demonstrated crucial interactions of the hits with the cofactor-binding site of hIMPDH2, further providing critical information for refining the design strategy. The present study reports the design and discovery of structurally novel hIMPDH2 inhibitors as potential anticancer agents and provides a guide for further research on the development of safe and effective anticancer agents, especially against glioblastoma.

肌苷5'-单磷酸脱氢酶（IMPDH）催化从头开始生物合成鸟嘌呤核苷酸，从而调节细胞增殖所需的鸟嘌呤核苷酸库。在这两种同工型中，人类2型IMPDH（h IMPDH2）是潜在的免疫抑制，抗病毒和抗癌化学疗法的经过验证的分子靶标。为了寻找新型的h IMPDH2抑制剂作为潜在的抗癌药，提出了三个新系列（A：5-氨基异苯并呋喃-1（3 H）-one，B：3,4-二甲氧基苯胺和C：苯并[ d ]-[1,3]合成了二氧杂-5-基甲胺）并进行了体外评估以及基于单元的活动。筛选了总共37个分子（29-65）的体外h IMPDH2抑制作用，尤其着重于建立其结构-活性关系（SAR）趋势。八种化合物（命中，30，31，33-35，37，41和43）表现出显著酶抑制（> 70％@10μM）; 尤其是A系列分子比B系列更有效（在10μM下，抑制率<70％），而C系列成员则没有活性。命中的h IMPDH2 IC ₅₀值范围为0.36至7.38μM 。表现出超过80％h IMPDH2抑制的命中（30，33，35，41和43）进一步评估其对癌症细胞系，例如细胞毒活性MDA-MB-231（乳腺腺癌），DU145（前列腺癌），U87 MG（成胶质细胞瘤星形细胞瘤）和正常细胞系，使用MTT分析法检测NIH-3T3（小鼠胚胎成纤维细胞）。与典型的h IMPDH2抑制剂麦考酚酸（MPA）相比，大多数化合物对癌细胞系表现出更高的细胞效力，对NIH-3T3细胞的毒性也要低得多。系列A的两首热门歌曲（30和35）在人外周血单核细胞（hPBMC）分析中进行了评估，发现其耐受性优于MPA。计算/预测的分子和理化性质对于药物相似性是令人满意的。分子对接研究清楚地证明了命中与h IMPDH2的辅因子结合位点之间的关键相互作用，进一步为完善设计策略提供了关键信息。本研究报告了结构上新颖的h IMPDH2抑制剂作为潜在抗癌药的设计和发现，并为进一步研究开发安全有效的抗癌药，尤其是针对胶质母细胞瘤的抗癌药提供了指导。