TRIM29 promotes pancreatic cancer MVI via IκBα K48-ubiquitination and NF-κB activation in CXCL5⁺ epithelial cells.

PURPOSE: To investigate the mechanisms underlying the interaction and influence between microvascular invasion (MVI), which contributes to metastasis and poor prognosis of pancreatic ductal adenocarcinoma (PDAC), and tumor microenvironment.

METHODS

This study employed an integrative multi-omics approach, combining spatial proteomics (multiplex immunofluorescence), transcriptome sequencing, and single-cell RNA sequencing (scRNA-seq) to profile MVI⁺ and MVI⁻ PDAC samples. The functional role of key genes was validated through in vitro and in vivo assays (migration, invasion, xenograft models). Molecular mechanisms were dissected using Co-IP, ubiquitination assays, and ChIP-qPCR.

RESULTS

The epithelial-mesenchymal transition (EMT) process was significantly activated in MVI⁺ tumors, with EMT-positive cells located spatially closer to microvessels. scRNA-seq identified a distinct epithelial subpopulation characterized by CXCL5 that exhibited a strong EMT phenotype and was enriched in MVI⁺ samples. Mechanistically, the transcription factor ZBTB7B was found to directly promote TRIM29 transcription. TRIM29 directly binds to IκBα via its BB2 domain and catalyzes its K48-linked ubiquitination and proteasomal degradation. This event relieves the inhibition of the NF-κB signaling pathway, leading to its activation and the subsequent induction of EMT, ultimately enhancing the invasive and metastatic capabilities of pancreatic cancer cells. Clinical correlation analysis revealed a significant negative correlation between TRIM29 and IκBα protein levels, and high TRIM29, low IκBα, and high CXCL5⁺EMT levels were all associated with poor prognosis.

CONCLUSION

This study reveals the critical role of the ZBTB7B-TRIM29-IκBα-NF-κB signaling axis in promoting EMT in CXCL5-marked pancreatic cancer cells surrounding MVI, establishing TRIM29 as a potential therapeutic target for inhibiting early metastasis of PDAC. CLINICAL RELEVANCE: This study provides deep insights into the biology of MVI, a crucial prognostic indicator in pancreatic cancer. TRIM29 expression could serve as a potential biomarker for predicting tumor aggressiveness and patient outcome. More importantly, targeting TRIM29’s E3 ligase activity or its interaction with IκBα represents a promising novel therapeutic strategy to inhibit early metastasis and improve the resectability of pancreatic cancer.