Hidden Molecular Switch Links H. pylori Infection to Aggressive Gastric Cancer

Helicobacter pylori, the spiral-shaped bacterium that colonizes the stomach lining of roughly half the world’s population, has long been recognized as the single most important environmental risk factor for gastric cancer. Yet the precise molecular choreography that transforms a chronic bacterial infection into uncontrolled malignant growth has remained only partially mapped. A new study published in BMC Cancer by researchers at Sanmen People’s Hospital in Zhejiang Province, China, now adds a critical piece to that puzzle, describing a four-component signaling axis that appears to drive malignant progression in H. pylori-associated gastric tumors.

The research team, led by corresponding authors Hongzhang Li and Jiaoe Chen, focused on two proteins that had not previously been connected in this context: ONECUT2, a transcription factor belonging to the one-cut domain family, and YOD1, a deubiquitinase enzyme that removes ubiquitin tags from target proteins. Their central finding is that ONECUT2 directly switches on the gene encoding YOD1, and that the resulting surge in YOD1 activity stabilizes STAT3, a well-known cancer-promoting signaling protein, which in turn ramps up production of PD-L1, the molecular shield that many tumors use to evade destruction by the immune system.

To establish this pathway, the investigators assembled clinical samples from gastric cancer patients, carefully stratified according to whether their tumors and adjacent para-carcinoma tissues came from H. pylori-positive or H. pylori-negative individuals. When they quantified gene expression using quantitative real-time polymerase chain reaction and protein levels using Western blotting, a consistent pattern emerged: ONECUT2, YOD1, and PD-L1 were all significantly upregulated in the H. pylori-infected gastric tissues compared with their counterparts from uninfected patients. The same elevation appeared in laboratory cultures of AGS and HGC-27 gastric cancer cells after deliberate infection with the bacterium, providing a controllable model system for mechanistic dissection.

With the correlation established, the team moved to causality. Using short hairpin RNA vectors to silence ONECUT2 in the infected cells, they observed a marked attenuation of the malignant phenotype. Cell proliferation, measured by CCK-8 colorimetric assays, EdU incorporation assays that label cells actively synthesizing DNA, and colony formation tests, all declined when ONECUT2 was depleted. Transwell migration and invasion assays, which track the ability of cells to squeeze through membrane barriers, showed the same directional change, indicating that ONECUT2 supports not only growth but also the invasive behavior that makes gastric cancer so dangerous clinically.

The mechanistic heart of the paper lies in demonstrating that YOD1 is a direct transcriptional target of ONECUT2. Two complementary techniques converged on this conclusion. In a dual luciferase reporter assay, the researchers showed that the presence of ONECUT2 increased the activity of a reporter gene placed under the control of the YOD1 promoter, a classic signature of transcriptional activation. Chromatin immunoprecipitation, or ChIP, then confirmed the physical basis of that activation by demonstrating that ONECUT2 binds directly to the YOD1 promoter region in living cells. Together, these experiments elevate the ONECUT2-YOD1 relationship from a statistical association to a defined regulatory interaction.

What YOD1 does once it is produced is equally instructive. Deubiquitinases of the ubiquitin-specific protease and related families act as molecular editors, stripping ubiquitin chains from proteins and thereby protecting them from degradation by the proteasome, the cell’s waste-disposal machinery. The study’s supplementary experiments, including co-immunoprecipitation to detect the endogenous interaction between YOD1 and STAT3, cycloheximide chase assays to measure protein half-life, and ubiquitination assays, showed that YOD1 physically associates with STAT3 and slows its degradation. When YOD1 was knocked down, STAT3 ubiquitination increased and the protein’s half-life shortened, meaning the transcription factor was being destroyed more rapidly. Conversely, abundant YOD1 allows STAT3 to accumulate and remain active longer, amplifying the downstream signal.

STAT3 is a signal transducer and activator of transcription with a well-documented role in inflammation-driven cancers, and its phosphorylated form, p-STAT3, was elevated in the infected cells in this study. The final link in the chain is PD-L1, programmed death-ligand 1, a cell-surface protein whose expression STAT3 can promote. PD-L1 binds the PD-1 receptor on T cells and effectively instructs the immune system to stand down, a trick that tumors exploit to escape immunosurveillance. The finding that the ONECUT2-YOD1-STAT3 cascade culminates in PD-L1 upregulation therefore suggests a mechanism by which chronic H. pylori infection might not only drive tumor growth but also actively blunt the anti-tumor immune response within the gastric microenvironment.

Perhaps the most convincing evidence for the pathway’s coherence came from rescue experiments. When the researchers overexpressed YOD1 in cells lacking ONECUT2, the suppressed proliferation and migration were partially restored, and the recovery was mediated through the STAT3/PD-L1 signaling pathway. This epistasis-style experiment, in which a downstream component compensates for the loss of an upstream one, is a standard test of whether a proposed linear pathway is real. The partial nature of the rescue also hints that ONECUT2 may influence additional targets beyond YOD1, a question that will likely guide future work in this area.

The clinical implications are twofold. First, the ONECUT2/YOD1/STAT3/PD-L1 axis offers a set of potential biomarkers: patients whose H. pylori-associated tumors show high expression of these proteins might be identified as having more aggressive disease or a more immunosuppressive microenvironment, potentially informing treatment selection. Second, each node in the axis represents a conceivable therapeutic target. Deubiquitinase inhibitors are an increasingly active area of drug development, and PD-L1 is already the target of approved immune checkpoint blockade therapies in multiple cancers, although the authors frame the PD-L1 connection here as suggesting a potential role in immune-related regulation rather than as a demonstrated treatment strategy. The study, which was approved by the Ethics Committee of Sanmen People’s Hospital and supported by the Zhejiang Medical and Health Science and Technology Plan, was published open access on 1 October 2026 under DOI 10.1186/s12885-026-17088-7. As with any cell-line and tissue-based investigation, the findings will need validation in larger patient cohorts and in vivo models before they translate into clinical practice, but they provide a mechanistically grounded explanation for how a common bacterial infection can push gastric cells toward both malignancy and immune evasion at the same time.

Subject of Research: The role of the ONECUT2/YOD1/STAT3/PD-L1 signaling axis in malignant progression of Helicobacter pylori-associated gastric cancer.

Article Title: ONECUT2-mediated transcriptional activation of YOD1 promotes malignant progression in H. pylori-associated gastric cancer through the STAT3/PD-L1 signaling

Article References: Chen, N., Fang, X., Chen, Q., Lin, J., Li, H., Li, H., & Chen, J. (2026). ONECUT2-mediated transcriptional activation of YOD1 promotes malignant progression in H. pylori-associated gastric cancer through the STAT3/PD-L1 signaling. BMC Cancer. https://doi.org/10.1186/s12885-026-17088-7

Image Credits: AI Generated

DOI: 10.1186/s12885-026-17088-7

Keywords: gastric cancer, Helicobacter pylori, ONECUT2, YOD1, STAT3, PD-L1, deubiquitinase, transcription factor, immune evasion, cancer immunology, gene regulation, tumor progression