Zhang Tianyi, Altouma Valerie, Sommers Joshua A, Dumm Adaira J, Kennedy Debbie, Xia Hongjie, Yang Mo, Fullenkamp Christopher R, Huang Shar-Yin N, Xue Yutong, Su Shuaikun, Shen Weiping, Haren Caitlin E, Kulikowicz Tomasz, Pommier Yves, Schneekloth John S, Garcia-Blanco Mariano A, Brosh Robert M, Wang Weidong
Lab of Genetics and Genomics, National Institute on Aging, NIH, Baltimore, Maryland, USA.
Translational Gerontology Branch, National Institute on Aging, NIH, Baltimore, Maryland, USA.
J Biol Chem. 2025 Aug 5;301(9):110547. doi: 10.1016/j.jbc.2025.110547.
Topoisomerase poisons are clinically used anticancer drugs that can induce DNA cleavage complexes to block replication. TOP3B is the only topoisomerase that can catalyze topological changes on either DNA or RNA and induce cleavage complexes on both nucleic acids. We proposed that TOP3B poisons may inhibit coronavirus RNA genome replication and tested this hypothesis by using mouse hepatitis coronavirus (MHV). We found that one of the two types of reported TOP3B poisons, thiacyanine dyes, possess potent inhibitory activities for MHV. Interestingly, the antiviral activity of the thiacyanine dyes is unaltered in Top3b-KO cells, suggesting that these dyes inhibit viral replication independent of TOP3B. Subsequent screening revealed that multiple members of the thiacyanine dye family have antiviral activity comparable to or stronger than remdesivir, the U.S. Food and Drug Administration (FDA)-approved drug for coronavirus, in an MHV-infected cell line model. One thiacyanine dye (NSC93472) significantly inhibits MHV replication in mouse lungs, showing its potential as an anticoronavirus drug. Mechanistic studies showed that NSC93472 preferentially binds two RNA fragments derived from SARS-CoV-2 genome over random ssRNA, interferes with assembly of an elongation-competent complex between the viral RNA-dependent RNA polymerase and the RNA template, and inhibits the RNA synthesis mediated by the RNA-dependent RNA polymerase. Moreover, NSC93472 can inhibit RNA synthesis by the reverse transcriptase of Moloney murine leukemia virus. Our studies demonstrate that thiacyanine dyes represent a new family of coronavirus inhibitors and suggest that TOP3B poisons and anti-RNA virus drugs share common characteristics in RNA binding and inhibition of enzymatic reactions on RNA.
拓扑异构酶毒物是临床上使用的抗癌药物，可诱导DNA裂解复合物来阻断复制。TOP3B是唯一一种能够催化DNA或RNA拓扑变化并在两种核酸上诱导裂解复合物的拓扑异构酶。我们提出TOP3B毒物可能抑制冠状病毒RNA基因组复制，并通过使用小鼠肝炎冠状病毒（MHV）来验证这一假设。我们发现，已报道的两种TOP3B毒物之一，硫代花青染料，对MHV具有强大的抑制活性。有趣的是，硫代花青染料的抗病毒活性在Top3b基因敲除细胞中未改变，这表明这些染料抑制病毒复制不依赖于TOP3B。随后的筛选显示，在MHV感染的细胞系模型中，硫代花青染料家族的多个成员具有与美国食品药品监督管理局（FDA）批准的抗冠状病毒药物瑞德西韦相当或更强的抗病毒活性。一种硫代花青染料（NSC93472）显著抑制小鼠肺部的MHV复制，显示出其作为抗冠状病毒药物的潜力。机制研究表明，NSC93472优先结合源自严重急性呼吸综合征冠状病毒2（SARS-CoV-2）基因组的两个RNA片段而非随机单链RNA，干扰病毒RNA依赖性RNA聚合酶与RNA模板之间延伸能力复合物的组装，并抑制由RNA依赖性RNA聚合酶介导的RNA合成。此外，NSC93472可抑制莫洛尼鼠白血病病毒逆转录酶的RNA合成。我们的研究表明，硫代花青染料代表了一类新的冠状病毒抑制剂，并表明TOP3B毒物和抗RNA病毒药物在RNA结合和抑制RNA酶促反应方面具有共同特征。
