Linking deubiquitination to pyroptosis: new perspectives from OTUB1 in hepatocellular carcinoma

Programmed cell death (PCD) is a tightly regulated process that orchestrates cellular demise in response to developmental cues and various types of environmental stress, aberrancy of which plays a critical role in the pathogenesis of a wide range of human diseases, including cancer, neurodegenerative disorders, and autoimmune conditions (1). Major forms of PCD include but are not limited to apoptosis, autophagy-dependent cell death, necroptosis, ferroptosis, and pyroptosis (2). Among these, pyroptosis has recently emerged as a distinct, lytic, pro-inflammatory form of cell death executed by members of the gasdermin (GSDM) protein family (3,4). Mechanistically, pyroptosis is driven by the proteolytic activation of GSDMs, which generate N-terminal pore-forming protein fragments that disrupt plasma membrane integrity (4). A major breakthrough in 2015 established gasdermin D (GSDMD) as the key executor of the canonical pyroptosis, whereby inflammatory caspases cleave GSDMD to release its N-terminal domain (GSDMD-NT), leading to membrane pore formation, osmotic lysis, and the release of pro-inflammatory cytokines such as interleukin-1β (IL-1β) and interleukin-18 (IL-18) (5,6). Subsequent research has expanded this paradigm by revealing functional diversity and partial redundancy within the GSDM family, including GSDMA, GSDMB, GSDMC, GSDMD, and GSDME. These proteins can be activated by proteases through cleavage-dependent or -independent mechanisms, including caspases, granzymes, and pathogen-derived enzymes (4,7). This evolving mechanistic framework has established pyroptosis as a key link connecting innate immunity, host defense against pathogens, and sterile inflammation (8). In the diseased liver, metabolic stress and inflammatory cues can converge to shape hepatocyte fate through multiple PCD pathways. Emerging evidence from human and experimental non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH) suggests that lipotoxic injury and tumor necrosis factor-alpha (TNF-α) driven inflammation engage pyroptotic, apoptotic, and necroptotic programs, thereby amplifying hepatic inflammation and creating a pathological context in which dysregulation of inflammatory cell death regulators may contribute to disease progression (9,10).

In the context of cancer, pyroptosis exhibits a dual yet increasingly appreciated tumor-suppressive role. Induction of pyroptosis can directly eliminate malignant cells while simultaneously promoting immunogenic cell death (ICD) (11). This process is characterized by the release of damage-associated molecular patterns (DAMPs) and inflammatory mediators that recruit and activate immune effector cells (11). Consequently, pyroptosis has been shown to synergize with immunotherapeutic strategies, particularly immune checkpoint blockade, thereby amplifying the anti-tumor immune effects to suppress tumorigenesis (12). However, despite these advances, the upstream regulatory mechanisms governing pyroptosis remain incompletely understood. In particular, the physiological role of the ubiquitin system, and especially deubiquitinases (DUBs), in modulating inflammasome activation, GSDM processing, and pyroptotic signaling is still poorly defined. Given the central importance of ubiquitination in controlling protein stability and signaling dynamics, elucidating how DUBs integrate into the pyroptotic network represents a critical gap in our current understanding and an important focus for future research.

In this context, a recent study by Chu et al. in the Journal of Gastrointestinal Oncology provides important insights into the upstream regulation of pyroptosis in hepatocellular carcinoma. In their work entitled “Silencing OTUB1 induces pyroptosis to inhibit the growth of liver cancer HepG2 cells via the NLRP3/caspase/GSDM signaling pathway”, the authors identify ovarian tumor domain-containing ubiquitin aldehyde binding protein 1 (OTUB1), a member of the DUB family, as a critical upstream regulator of pyroptotic cell death (13). Through bioinformatics analysis of patient datasets, the authors first demonstrate that elevated OTUB1 expression is closely associated with poor prognosis in liver cancer, suggesting a potential oncogenic role for OTUB1. Functional studies further reveal that silencing OTUB1 significantly suppresses HepG2 cell proliferation while inducing pyroptotic cell death. Mechanistically, OTUB1 knockdown activates the NLR family pyrin domain containing 3 (NLRP3) inflammasome-caspase-GSDM signaling axis, a central pathway governing pyroptosis (Figure 1). In addition, the study suggests that OTUB1 may modulate pyroptosis through broader oncogenic signaling networks, including the β-catenin, signal transducer and activator of transcription 3 (STAT3), and transforming growth factor-β (TGF-β)/Smad pathways. Although the precise molecular mechanisms remain incompletely understood, these findings collectively establish OTUB1 as a previously unrecognized upstream regulator that links ubiquitin signaling to pyroptotic cell death. Taken together, this work not only expands the current understanding of DUB-mediated regulation of cell death, but also highlights OTUB1 as a potential therapeutic target in hepatocellular carcinoma (13).

Figure 1 OTUB1 silencing promotes pyroptosis through activation of the NLRP3-caspase-GSDM axis in HepG2 cells. OTUB1 silencing activates the NLRP3 inflammasome and enhances caspase-dependent pyroptotic signaling in HepG2 cells. Increased activation of caspase-1 and caspase-4 may contribute to GSDMD processing, whereas activation of apoptotic caspases, including caspase-3 and caspase-8, may contribute to GSDME processing. These events collectively promote pyroptotic cell death in HepG2 cells to impact tumorigenesis. GSDMD, gasdermin D; GSDME, gasdermin E; NLRP3, NLR family pyrin domain containing 3; OTUB1, ovarian tumor domain-containing ubiquitin aldehyde binding protein 1.

Collectively, this work further supports an emerging concept that deubiquitination represents a critical upstream checkpoint in inflammasome activation and pyroptotic signaling. Increasing evidence suggests that DUBs can directly modulate key components of the pyroptotic machinery (14). For example, OTU deubiquitinase 4 (OTUD4) has been reported to promote pyroptosis by deubiquitinating and stabilizing GSDME, thereby enhancing radiosensitivity in nasopharyngeal carcinoma (15). Similarly, a recent study, using CRISPR-Cas9-based approaches and lactate dehydrogenase (LDH) release assays, demonstrated that ubiquitin specific peptidase 48 (USP48) increases GSDME stability by removing K48-linked ubiquitin chains, thereby identifying USP48 as a potential driver of pyroptosis (16). In this framework, the study by Chu et al. (13) extends the landscape of DUB-mediated pyroptosis by implicating OTUB1 in regulating the NLRP3-caspase-GSDM axis and revealing its close association with oncogenic signaling pathways. This convergence indicates the potential presence of a larger regulatory network that combines ubiquitin signaling, oncogenic pathways, and inflammatory cell death programs. These findings raise an intriguing possibility that targeting DUBs may reprogram tumor cell fate by shifting the balance between survival and inflammatory cell death, thereby offering a conceptual framework for developing next-generation therapeutic strategies.

While this study provides important insights into the involvement of OTUB1 in regulating pyroptosis in hepatocellular carcinoma, the underlying molecular mechanisms remain to be further clarified. Notably, OTUB1 deficiency is associated with reduced abundance of GSDMD and GSDME, suggesting that its role in pyroptotic regulation may be more complex than initially appreciated. However, it remains unclear whether OTUB1 directly regulates pyroptosis by modulating protein stability or the ubiquitination of key inflammasome components, or whether it primarily acts through upstream signaling networks to indirectly reshape cell death programs. Clarifying this distinction will be essential for precisely defining the hierarchical position of OTUB1 within inflammatory cell death pathways. Additionally, the study reports decreased intracellular levels of IL-1β and IL-18; however, it remains unclear whether this indicates reduced cytokine production or increased secretion after membrane pore formation during pyroptosis. Given that intracellular abundance and extracellular release represent distinct biological readouts in pyroptosis, future studies incorporating measurements of culture supernatants, discrimination between precursor and mature cytokine forms, and direct analyses of secretion dynamics will be important to resolve this issue and establish the causal relationship between OTUB1 silencing and inflammatory cytokine release.

More broadly, the functional interplay between deubiquitinases and pyroptosis is likely far more intricate than a simple linear pathway, encompassing coordinated regulation of protein stability, inflammasome assembly, cell fate determination, and tumor microenvironment remodeling to influence tumorigenesis (17). In this regard, the study from Chu et al. provides a valuable foundation linking OTUB1, pyroptosis, and hepatocellular carcinoma progression (13). However, moving the field forward will require not only deeper mechanistic dissection at the molecular level, but also concerted efforts from translational and clinical research to harness these insights into actionable biomarkers and therapeutically exploitable strategies.

Acknowledgments

None.

Footnote

Provenance and Peer Review: This article was commissioned by the editorial office, Journal of Gastrointestinal Oncology. The article has undergone external peer review.

Peer Review File: Available at https://jgo.amegroups.com/article/view/10.21037/jgo-2026-0317/prf

Funding: This work was supported in part by the NIH (grant No. R35CA253027).

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jgo.amegroups.com/article/view/10.21037/jgo-2026-0317/coif). All authors report that this work was supported in part by the NIH grant R35CA253027. The authors have no other conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

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References

1. Galluzzi L, Vitale I, Aaronson SA, et al. Molecular mechanisms of cell death: recommendations of the Nomenclature Committee on Cell Death 2018. Cell Death Differ 2018;25:486-541. [Crossref] [PubMed]
2. Xavier RJ, Huett A, Rioux JD. Autophagy as an important process in gut homeostasis and Crohn's disease pathogenesis. Gut 2008;57:717-20. [Crossref] [PubMed]
3. Liu X, Zhang Z, Ruan J, et al. Inflammasome-activated gasdermin D causes pyroptosis by forming membrane pores. Nature 2016;535:153-8. [Crossref] [PubMed]
4. Shi J, Gao W, Shao F. Pyroptosis: Gasdermin-Mediated Programmed Necrotic Cell Death. Trends Biochem Sci 2017;42:245-54. [Crossref] [PubMed]
5. Shi J, Zhao Y, Wang K, et al. Cleavage of GSDMD by inflammatory caspases determines pyroptotic cell death. Nature 2015;526:660-5. [Crossref] [PubMed]
6. Kayagaki N, Stowe IB, Lee BL, et al. Caspase-11 cleaves gasdermin D for non-canonical inflammasome signalling. Nature 2015;526:666-71. [Crossref] [PubMed]
7. Zhang Z, Zhang Y, Xia S, et al. Gasdermin E suppresses tumour growth by activating anti-tumour immunity. Nature 2020;579:415-20. [Crossref] [PubMed]
8. Bai Y, Pan Y, Liu X. Mechanistic insights into gasdermin-mediated pyroptosis. Nat Rev Mol Cell Biol 2025;26:501-21. [Crossref] [PubMed]
9. Afonso MB, Rodrigues PM, Carvalho T, et al. Necroptosis is a key pathogenic event in human and experimental murine models of non-alcoholic steatohepatitis. Clin Sci (Lond) 2015;129:721-39. [Crossref] [PubMed]
10. Ezquerro S, Mocha F, Frühbeck G, et al. Ghrelin Reduces TNF-α-Induced Human Hepatocyte Apoptosis, Autophagy, and Pyroptosis: Role in Obesity-Associated NAFLD. J Clin Endocrinol Metab 2019;104:21-37. [Crossref] [PubMed]
11. Krysko DV, Garg AD, Kaczmarek A, et al. Immunogenic cell death and DAMPs in cancer therapy. Nat Rev Cancer 2012;12:860-75. [Crossref] [PubMed]
12. Wang Y, Gao W, Shi X, et al. Chemotherapy drugs induce pyroptosis through caspase-3 cleavage of a gasdermin. Nature 2017;547:99-103. [Crossref] [PubMed]
13. Chu WQ, Xu RL, Liu MN, et al. Silencing OTUB1 induces pyroptosis to inhibit the growth of liver cancer HepG2 cells via the NLRP3/caspase/GSDM signaling pathway. J Gastrointest Oncol 2026;17:86. [Crossref] [PubMed]
14. Hsu SK, Kuo IY, Lin PY, et al. Deubiquitinating enzymes: Key regulators of ferroptosis and pyroptosis and novel targets for cancer intervention. Int J Biol Sci 2025;21:3993-4009. [Crossref] [PubMed]
15. Di M, Miao J, Pan Q, et al. OTUD4-mediated GSDME deubiquitination enhances radiosensitivity in nasopharyngeal carcinoma by inducing pyroptosis. J Exp Clin Cancer Res 2022;41:328. [Crossref] [PubMed]
16. Ren Y, Feng M, Hao X, et al. USP48 Stabilizes Gasdermin E to Promote Pyroptosis in Cancer. Cancer Res 2023;83:1074-93. [Crossref] [PubMed]
17. Broz P, Dixit VM. Inflammasomes: mechanism of assembly, regulation and signalling. Nat Rev Immunol 2016;16:407-20. [Crossref] [PubMed]