# TCN1 Drives Malignant Progression of Pancreatic Cancer Through STAT4-Mediated Transcriptional Activation of the DUOX2/ROS Signaling Axis

## TL;DR

TCN1 promotes pancreatic cancer progression by activating a signaling pathway involving STAT4 and DUOX2, which increases reactive oxygen species and cancer cell aggression.

## Contribution

Discovery of a novel TCN1–STAT4–DUOX2/ROS signaling axis that drives pancreatic cancer progression and may serve as a therapeutic target.

## Key findings

- TCN1 overexpression is associated with worse survival and aggressive tumor features in pancreatic cancer.
- TCN1 activates STAT4, which in turn upregulates DUOX2 and increases ROS to promote cancer progression.
- Antioxidants reduce TCN1-driven cancer aggression, highlighting ROS as a critical mediator.

## Abstract

Pancreatic ductal adenocarcinoma is one of the deadliest cancers, and new biomarkers and treatment targets are urgently needed. We found that the protein transcobalamin 1 (TCN1) is markedly increased in pancreatic tumors and is linked to worse clinicopathologic features and poorer survival. In cell and mouse models, raising TCN1 enhanced tumor cell growth, movement, and invasion, while lowering TCN1 reduced these behaviors. Our data indicate that TCN1 is associated with the transcription factor STAT4, which in turn activates DUOX2 and elevates intracellular reactive oxygen species (ROS). Reducing STAT4 or DUOX2, or removing ROS with the antioxidants N-acetylcysteine or Tempol, weakened the aggressive effects driven by TCN1. These results suggest that the TCN1–STAT4–DUOX2/ROS pathway contributes to pancreatic cancer progression and that TCN1 may serve as a prognostic biomarker and potential therapeutic entry point.

Background: Pancreatic ductal adenocarcinoma (PDAC) is characterized by its aggressive clinical behavior and intricate microenvironment regulation, leading to dismal prognosis. Elucidating the molecular mechanisms underlying PDAC pathogenesis is crucial for developing improved therapeutic approaches. The functional significance and molecular basis of transcobalamin 1 (TCN1) in PDAC remain largely unexplored. Methods and Results: Through integrated analysis of TCGA and GTEx datasets combined with 80 clinical specimens, we identified significant TCN1 overexpression in PDAC, showing a positive association with tumor stage and negative associations with histological differentiation and overall survival. Functional investigations showed that TCN1 enhanced pancreatic cancer cell proliferation, migration, invasion, and epithelial–mesenchymal transition (EMT) in both in vitro and in vivo models. Mechanistically, TCN1 physically interacts with signal transducer and activator of transcription 4 (STAT4) to enhance its transcriptional activity. Chromatin immunoprecipitation (ChIP) assays showed that STAT4-mediated transcriptional activation of dual oxidase 2 (DUOX2) occurs through direct promoter binding. As a pivotal reactive oxygen species (ROS)-generating enzyme, DUOX2 overexpression elevates intracellular ROS levels, thereby promoting EMT progression and activating proliferation-related signaling cascades. Antioxidant treatment effectively abrogated TCN1-driven oncogenic phenotypes, establishing ROS as the critical downstream mediator. Conclusions: Collectively, our findings reveal a novel TCN1/STAT4/DUOX2 regulatory axis that exacerbates PDAC progression by remodeling redox homeostasis. This signaling cascade may serve as a prognostic biomarker and a potential therapeutic target for ROS-directed precision therapy in PDAC.