Using diverse arylmethyl groups to replace the benzyl moiety of the lead Hsp90 inhibitor 1 (N-(5-chloro-2,4-dihydroxybenzoyl)-(R)-N-benzyl-1,2,3,4-tetrahydro-3-iso quinolinecarboxamide), thirty four derivatives (10–43) were developed, and exhibited improved Hsp90 inhibitory and antiproliferative activities. SAR analysis indicated that the southeastern aryl substitutions influenced their antiproliferative activities obviously, with the para-pyridyl group (41) outperforming all other substitution patterns. In this regard, compound 41 was selected for further evaluation. CETSA melt and ITDRF_CETSA (isothermal dose-response fingerprint) curves for Hsp90α further proved that 41 interacted with intracellular Hsp90α powerfully. Compared with the lead compound 1, docking and MD refinement of the Hsp90α-41 complex revealed a favorable H-bonding interaction between the side-chain of Tyr139 and the pyridine moiety of 41, which is the first time to be used for resorcinol-based Hsp90 inhibitors. With broad-spectral antitumor activity, compound 41 induced time- and dose-dependent growth inhibition and G0/G1 cell cycle arrest on human breast cancer MDA-MB-453 cell line. In addition, flow cytometry and Western blot analyses confirmed that 41 induced apoptosis of human breast cancer MDA-MB-453 cell line. Via degradation of IKKs and suppression of IKKs activity, compound 41 inhibited TNF-α-induced NF-κB activation. The overall properties warrant compound 41 a promising Hsp90 inhibitor and further biological characterizations. This study provides insights into the chemical evolution of Hsp90 inhibitors, and may facilitate the design of next generation Hsp90 inhibitors for the antitumor drug development.

使用不同的芳基甲基取代铅Hsp90抑制剂1（N-（5-氯-2,4-二羟基苯甲酰基）-（R）-N-苄基-1,2,3,4-四氢-3-异喹啉甲酰胺），已开发出三十四种衍生物（10 – 43），并表现出改善的Hsp90抑制和抗增殖活性。SAR分析表明，东南芳基取代明显影响了它们的抗增殖活性，对-吡啶基（41）的表现优于所有其他取代方式。在这方面，选择化合物41作进一步评估。CETSA熔体和ITDRF _CETSAHsp90α的（等温剂量反应指纹图谱）曲线进一步证明了41与细胞内Hsp90α产生了强大的相互作用。与铅化合物1相比，Hsp90α- 41配合物的对接和MD精炼显示Tyr139的侧链与41的吡啶部分之间具有良好的H键相互作用，这是首次用于间苯二酚基Hsp90抑制剂。具有广谱抗肿瘤活性，化合物41在人乳腺癌MDA-MB-453细胞系上诱导了时间和剂量依赖性的生长抑制和G0 / G1细胞周期停滞。此外，流式细胞仪和蛋白质印迹分析证实了41诱导人乳腺癌MDA-MB-453细胞凋亡。通过IKK的降解和IKK活性的抑制，化合物41抑制了TNF-α诱导的NF-κB活化。总体性质保证化合物41是一种有前途的Hsp90抑制剂，并具有进一步的生物学特性。这项研究为Hsp90抑制剂的化学进化提供了见识，并可能有助于设计用于抗肿瘤药物开发的下一代Hsp90抑制剂。