Enhanced Collagen Secretion in Epithelial Cancer Cells is associated with L1CAM Deficiency

Collagen, a critical component of the tumor microenvironment (TME), significantly influences cancer-associated fibrosis, tissue stiffness, immune response, and metastasis. Pancreatic ductal adenocarcinoma (PDAC) is characterized by excessive collagen deposition, and effective therapies remain limited. Our research challenges conventional understanding by highlighting the remarkable ability of specific tumor epithelial populations, particularly those with low levels of L1 cell adhesion molecule (L1CAM) expression (L1low), to actively modulate collagen dynamics within the TME. Transcriptome analysis of PDAC cells with varying L1 expression reveals shifts in collagen-related pathways, with heightened expression of collagen 17A1 (COL17A1) in L1low cells. Alongside, L1low cells exhibit enhanced migratory capacity. In an orthotopic mouse model, L1low cancer cells demonstrate increased collagen deposition, resistance to gemcitabine treatment, and an elevated propensity for liver metastases. Treatment with Tranilast, an anti-fibrotic drug, significantly reduces tumor volume and collagen deposition while enhancing L1 expression. This, in turn, mitigates tumor invasiveness and suppresses metastases formation. Overall, our study uncovers a novel role for L1CAM in PDAC aggressiveness and fibrosis, revealing a new epithelial population capable of collagen secretion and challenging the traditional notion that this function is solely attributed to stromal cells. To investigate the transcriptional differences between PDAC cells with different L1CAM levels, we FACS sorted the L3.6pl cells for high and low levels of L1CAM (L1CAMpositive and L1CAMnegative). We then performed gene expression profiling analysis using data obtained from RNA-seq of the 2 different cellular populations (L3.6pl L1CAMpositive versus L3.6pl L1CAMnegative)