Col1a1 Knockdown Suppresses EMT, Migration, and Invasion of Oral Squamous Cell Carcinoma both In Vitro and In Vivo.

Utilizing a 4-NQO-induced murine model and single-cell RNA sequencing, we identified a distinct Collagen Type I Alpha 1 Chain (Col1a1+) epithelial subpopulation that is significantly expanded in OSCC, exhibits the highest epithelial-mesenchymal transition (EMT) signature, and correlates with poor patient survival. Functional studies demonstrated that Col1a1 knockdown in OSCC cell lines (HSC3) attenuated TGF-β-induced EMT, impaired migration and invasion in vitro, and reduced tumor burden in a conditional knockout mouse model.

Transcriptomic profiling following Col1a1 silencing revealed the suppression of TGF-β signaling and ECM-receptor interaction pathways. We further identified BMP1 as a key downstream effector, demonstrating a direct physical interaction between COL1A1 and BMP1, and showed that COL1A1 potentiates BMP1's proteolytic activity. Rescue experiments confirmed that BMP1 is essential for COL1A1-driven tumor growth, metastasis, and TGF-β pathway activation in vivo.