Derivation and characterization of ubiquitin-specific protease 18 inhibitors

Authors

• Blessing O. Ogunlade, Frederick National Laboratory for Cancer Reseaerch, Frederick, MD
• Kevin N. Dalby, The University of Texas at Austin, Austin, TX
• Samuel C. Okpechi, Frederick National Laboratory for Cancer Research, Frederick, MD
• Eun Jeong Cho, The University of Texas at Austin, Austin, TX
• Liliya Tyutyunyk-Massey, Frederick National Laboratory for Cancer Research, Frederick, MD
• Zibo Chen, Frederick National Laboratory for Cancer Research, Frederick, MD
• Xiuxia Liu, Frederick National Laboratory for Cancer Research, Frederick, MD
• Joseph Ivanic, Frederick National Laboratory for Cancer Research, Frederick, MD
• Brian Luke, Frederick National Laboratory for Cancer Research, Frederick, MD
• Shyamal D. Desai, LSU Health Sciences Center - New OrleansFollow
• Yair Alfaro, Frederick National Laboratory for Cancer Research, Frederick, MD
• Ashwini K. Devkota, The University of Texas at Austin, Austin, TX
• Rae M. Sammons, The University of Texas at Austin, Austin, TX
• Gilbert G. Privé, University of Toronto, Toronto, Canada
• Xi Liu, Frederick National Laboratory for Cancer Research, Frederick, MD
• Ethan Dmitrovsky, Frederick National Laboratory for Cancer Research, Frederick, MD

Document Type

Article

Publication Date

5-19-2026

Publication Title

JCI Insight

Abstract

Ubiquitin-Specific Protease 18 (USP18) is a deISGylation enzyme and antineoplastic target. To develop USP18 inhibitors, an enzymatically active human recombinant USP18 protein was engineered suitable for high-throughput screening of ~80,000 chemical compounds. Three of them substantially inhibited USP18 enzymatic activity with β-lapachone having prominent antineoplastic activity. Independent β-lapachone treatments of murine and human lung cancer cell lines statistically-significantly reduced proliferation and increased apoptosis. Gain of USP18 expression antagonized these effects. β-lapachone treatments statistically-significantly repressed lung cancer xenograft growth. β-lapachone increased reactive oxygen species (ROS), but antineoplastic effects occurred at dosages with negligible ROS production. ROS scavenger treatments did not rescue β-lapachone effects at these concentrations, consistent with an ROS-independent mechanism. Interferon-Stimulated Response Element (ISRE) reporter assays following β-lapachone treatment activated this reporter. USP18 co-transfection antagonized this activity. β-lapachone treatments increased global ISGylation. RNA sequencing of lung cancer cells engineered with or without enhanced USP18 expression showed specific pathways affected by β-lapachone treatment. Proteomic analysis of these treated cells revealed known and new ISGylated proteins. In silico modeling identified a unique USP18 pocket where these USP18 inhibitors bind. Engineered mutation of this pocket disrupted β-lapachone activity. Taken together, β-lapachone is an antineoplastic tool compound useful for USP18 inhibitor development.

First Page

1

Last Page

21

PubMed ID

42154529

Volume

11

Issue

14

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Recommended Citation

Ogunlade, Blessing O.; Dalby, Kevin N.; Okpechi, Samuel C.; Cho, Eun Jeong; Tyutyunyk-Massey, Liliya; Chen, Zibo; Liu, Xiuxia; Ivanic, Joseph; Luke, Brian; Desai, Shyamal D.; Alfaro, Yair; Devkota, Ashwini K.; Sammons, Rae M.; Privé, Gilbert G.; Liu, Xi; and Dmitrovsky, Ethan, "Derivation and characterization of ubiquitin-specific protease 18 inhibitors" (2026). School of Medicine Faculty Publications. 4836.
https://digitalscholar.lsuhsc.edu/som_facpubs/4836
10.1172/jci.insight.202853