Abstract 4294: The emerging role of deubiquitinase enzymes in lung cancer plasticity
Authors: Kwon Juntae , Zhang Jinmin , Mok Boram , Allsup Samuel , Han Cecil 
Published: March 2024

Abstract
Lung cancer is characterized by a high degree of genetic and molecular heterogeneity. Lineage plasticity has emerged as a source of intratumoral heterogeneity and drug resistance, resulting in poor prognosis and treatment failure. The molecular mechanisms driving lung cancer plasticity remain unclear. Ubiquitin-Specific Peptidase 13 (USP13), a deubiquitinating enzyme, is one of the most amplified genes in lung squamous cell carcinoma (LUSC). We developed a USP13 knock-in overexpressing mouse model in KrasLSL-G12D/+; Trp53fl/fl (KP) background (KPU mice). USP13 overexpression resulted in aggressive tumorigenesis and a shortened survival in Kras/Trp53-driven lung cancer. Notably, while KP mice developed lung adenocarcinoma (LUAD), KPU mice developed LUSC and LUAD. LUSC in KPU mice faithfully recapitulated the key pathohistological, molecular features, and cellular pathways of human LUSC. Bulk RNA-sequencing analysis showed that KPU tumors were heterogeneous and enriched in lineage reprogramming pathways including basal cell signaling, stem cell pluripotency, and epithelial-mesenchymal transition (EMT). Using cell-type-restricted adenoviral Cre to target cells expressing surfactant protein C (SPC) or club cell antigen 10 (CC10), we identified bronchiolar secretory club cells as the predominant cell origin of LUSC. USP13 altered the levels of lineage transcription factors such as TTF-1 and SOX2 in club cells during early tumorigenesis. Altered expression of these factors reinforced the fate of CC10+ club cells to squamous carcinoma development rather than adenocarcinoma. In addition, USP13 directly acted on the K48-linked ubiquitination of c-Myc and increased its protein stability, contributing to the elevation of squamous gene expression (SOX2, CK5, P40) in the primary mouse and advanced human lung cancer cells. These results suggest that USP13 promotes lineage plasticity in club cells during the early stage of cancer development and drives reprogramming into LUSC. We also found a potential functional association between USP13 and EMT pathway. Notably, irrespective of cell origin, USP13 overexpression enhanced EMT marker expression including N-cadherin, SNAI1, and ZEB1 in lung cancer cells, promoting cell migration and invasion. USP13 increased tumorigenic and metastatic abilities of lung cancer cells in 3D organoid culture and syngeneic mouse models. Collectively, our research highlights the pivotal significance of USP13 in unleashing lineage plasticity during lung cancer progression, suggesting the potential role of deubiquitinase enzymes in regulating lineage plasticity, which may lead to novel therapeutics for treating lung cancer.
Citation Format: Juntae Kwon, Jinmin Zhang, Boram Mok, Samuel Allsup, Cecil Han. The emerging role of deubiquitinase enzymes in lung cancer plasticity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4294.