GRL0617

GRL0617 is a selective, competitive non-covalent inhibitor of severe acute respiratory syndrome coronavirus papain-like protease (SARS-CoV PLpro), with an IC₅₀ value of 0.6μM and a Kᵢ value of 0.49μM^[1]. By inhibiting the proteolytic activity of PLpro, GRL0617 blocks the hydrolytic processing of viral polyproteins, thereby significantly reducing the replication efficiency of SARS-CoV-2. Its half-maximal effective concentration (EC₅₀) in Vero E6 cells ranges from 13.1 to 14.5μM^[2]. GRL0617 effectively inhibits the deISGylating activity of PLpro, restoring the host innate immune pathway mediated by interferon-stimulated gene 15 (ISG15), thereby enhancing the cell's intrinsic immune response against viral infection^[3-4].

In vitro, pretreatment of SARS-CoV-2-infected Vero E6 cells with GRL0617 (1.56–100μM) for 24–48 hours significantly reduced viral replication efficiency by inhibiting the proteolytic activity of PLpro^[5]. Treatment of KYSE30 and KYSE510 esophageal squamous cell carcinoma cells with GRL0617 (5–10μM) for 24 hours reduced SLC7A11 protein expression levels by inhibiting deubiquitinase activity, significantly suppressing cell proliferation and colony formation ability, while increasing intracellular reactive oxygen species (ROS) levels^[6].

References:
[1] Ratia K, Pegan S, Takayama J, et al. A noncovalent class of papain-like protease/deubiquitinase inhibitors blocks SARS virus replication. Proc Natl Acad Sci U S A. 2008 Oct 21;105(42):16119-24.
[2] Calleja DJ, Lessene G, Komander D. Inhibitors of SARS-CoV-2 PLpro. Front Chem. 2022 Apr 26;10:876212.
[3] Cho CC, Li SG, Lalonde TJ, et al. Drug Repurposing for the SARS-CoV-2 Papain-Like Protease. ChemMedChem. 2022 Jan 5;17(1):e202100455. doi: 10.1002/cmdc.202100455. Epub 2021 Oct 12. Erratum in: ChemMedChem. 2022 Mar 4;17(5):e202200053.
[4] Shen Z, Ratia K, Cooper L, et al. Potent, Novel SARS-CoV-2 PLpro Inhibitors Block Viral Replication in Monkey and Human Cell Cultures. bioRxiv [Preprint]. 2021 Feb 15:2021.02.13.431008.
[5] Fu Z, Huang B, Tang J et al. The complex structure of GRL0617 and SARS-CoV-2 PLpro reveals a hot spot for antiviral drug discovery. Nat Commun. 2021 Jan 20;12(1):488.
[6] Li WT, Jin X, Song SJ, et al. Blocking SLC7A11 attenuates the proliferation of esophageal squamous cell carcinoma cells. Anim Cells Syst (Seoul). 2024 May 11;28(1):237-250.

GRL0617是一种选择性的、竞争性非共价的严重急性呼吸综合征冠状病毒木瓜样蛋白酶（SARS-CoV PLpro）抑制剂，其IC₅₀值为0.6μM，Kᵢ值为0.49μM^[1]。GRL0617通过抑制PLpro的蛋白酶活性，阻断病毒多蛋白的水解加工过程，从而显著降低SARS-CoV-2的病毒复制效率，其在Vero E6细胞中的半数有效浓度（EC₅₀）为13.1至14.5μM^[2]。GRL0617能够有效抑制PLpro的去ISG化活性，恢复干扰素刺激基因15（ISG15）介导的宿主天然免疫通路，进而增强细胞对抗病毒感染的固有免疫反应^[3-4]。
在体外，GRL0617（1.56–100μM）预处理SARS-CoV-2感染的Vero E6细胞24–48小时，通过抑制PLpro的蛋白酶活性，显著降低病毒复制效率^[5]。GRL0617（5–10μM）处理KYSE30和KYSE510食管鳞癌细胞24小时，通过抑制去泛素化酶活性降低SLC7A11蛋白表达水平，显著抑制细胞增殖和集落形成能力，同时增加细胞内活性氧（ROS）水平^[6]。