Institute for Clinical and Molecular Virology, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, 91054 Erlangen, Germany.
4SC AG/4SC Discovery GmbH, Fraunhoferstraße 22, 82152 Planegg-Martinsried, Germany.
Int J Mol Sci. 2022 Feb 24;23(5):2493. doi: 10.3390/ijms23052493.
Human cytomegalovirus (HCMV) is a pathogenic human herpesvirus associated with serious, potentially life-threatening symptoms in the immunocompromised or immunonaïve host. The limitations encountered by antiviral therapy options currently available include a narrow panel of accessible targets, the induction of viral drug resistance as well as severe drug dosage-mediated side-effects. Improved drug-targeting strategies to resolve these issues are the focus of our investigations. In particular, pharmaceutical kinase inhibitors (PKIs), either directed to host kinases or directed to the viral protein kinase pUL97, have been considered to overcome these restrictions. Recently, we reported the identification of a synergistic combination of two PKIs directed to host cyclin-dependent kinase 7 (CDK7) and viral CDK ortholog pUL97. Here, we substantiate these findings with the following results: (i) true drug synergy was exhibited by various chemical classes of PKI pairs directed to pUL97 and CDK7; (ii) no putative amplification of cytotoxicity by these drug combinations was observed; (iii) a reduction in drug dosage levels for synergistic combinations was defined on a quantitative basis and compared to monotreatments; (iv) the quantities of target proteins CDK7 and pUL97 expressed in HCMV-infected cells were assessed by confocal imaging, indicating a strong down-modulation of CDK7 levels as a result of synergistic drug treatment; (v) the functional importance of these target kinases, both binding to cyclin H, was illustrated by assessing HCMV replication under the viral genomic deletion of ORF-UL97 or cellular cyclin knock-out; (vi) new combinations of HCMV-specific drug synergy were demonstrated for solely host-directed treatments using PKIs against CDK2, CDK7, CDK8 and/or CDK9 and (vii) a triple PKI combination provided further support for the synergy approach. With these combined findings, this study highlights the potential of therapeutic drug combinations of approved, developmental and preclinical PKIs for expanding future options for anti-HCMV therapy.
人巨细胞病毒（HCMV）是一种致病性人类疱疹病毒，与免疫功能低下或免疫幼稚宿主的严重、潜在危及生命的症状有关。目前可用的抗病毒治疗选择所遇到的限制包括可访问目标的范围狭窄、诱导病毒药物耐药性以及严重的药物剂量介导的副作用。改进药物靶向策略以解决这些问题是我们研究的重点。特别是，已经考虑到针对宿主激酶或针对病毒蛋白激酶 pUL97 的药物激酶抑制剂（PKIs）来克服这些限制。最近，我们报道了鉴定针对宿主细胞周期蛋白依赖性激酶 7（CDK7）和病毒 CDK 同源物 pUL97 的两种 PKI 的协同组合。在这里，我们用以下结果证实了这些发现：（i）针对 pUL97 和 CDK7 的各种化学类别的 PKI 对表现出真正的药物协同作用；（ii）这些药物组合没有观察到细胞毒性的潜在放大；（iii）基于定量比较，协同组合降低了药物剂量水平，并与单药治疗进行了比较；（iv）通过共聚焦成像评估 HCMV 感染细胞中 CDK7 和 pUL97 靶蛋白的表达量，表明协同药物治疗导致 CDK7 水平强烈下调；（v）通过评估 ORF-UL97 缺失或细胞周期蛋白敲除下的 HCMV 复制，说明了这些靶激酶（均与 cyclin H 结合）的功能重要性；（vi）使用针对 CDK2、CDK7、CDK8 和/或 CDK9 的仅针对宿主的 PKI 证明了新的 HCMV 特异性药物协同作用组合；（vii）三重 PKI 组合为协同方法提供了进一步支持。综合这些发现，本研究强调了批准、开发中和临床前 PKI 的治疗性药物组合在扩大抗 HCMV 治疗未来选择方面的潜力。
