Colorectal cancer (CRC) is the third most common cancer, with tumor progression influenced by interactions between the tumor microenvironment and the extracellular matrix (ECM). Fibrillar collagen, the main ECM component, is more abundant in tumor tissues than in normal tissues and its remodeling plays a crucial role in CRC tumor progression. Cells interact with collagen through integrins and discoidin-domain receptors (DDR), particularly DDR1. A clinical study carried out by our research team on CRC patients revealed high DDR1 expression in tumors tissues, associated with shorter event free survival. As metastases occur in 40-60% of CRC cases, this study aims to investigate the role of DDR1 in metastatic progression.

To investigate DDR1’s role in CRC progression, HT-29 and HCT-116 colorectal cell lines were selected. DDR1 inhibition was achieved using the pharmacological tyrosine kinase inhibitors, DDR1-IN-1 and Nilotinib, while DDR1 knockdown was performed using shRNA targeting DDR1. Cell migration and invasion were assessed using wound healing assays, Boyden chamber assay and live-cell imaging. Invasion efficiency was analyzed in spheroid collagen type I invasion assay. DDR1 interaction with its new partner was performed using BRET saturation assays and proximity ligation assays (PLA).

Our findings reveal that DDR1 overexpression in poorly invasive HT-29 cells enhances cell escape and spheroid growth. Conversely, DDR1 pharmacological inhibition by Nilotinib or DDR1-IN-1 and DDR1 downregulation by shRNA in HCT-116 cells significantly reduce migration (wound healing assay) and invasion (Boyden chamber assay). Time-lapse videomicroscopy study confirms that DDR1 inhibition significantly decreases migration in a 3D collagen matrix, while spheroid models show a decrease in invasive capacity of colorectal cancer cell lines whithin a type I collagen rich matrix. As metalloproteinases (MMPs) play a key role in ECM degradation and tumor invasion, we demonstrate that DDR1 promotes matrix remodeling through MMP activation. Moreover, DDR1 can also form heterodimers with other receptors leading to cancer progression. Using a BRET saturation assay, we identified a novel DDR1 partner involved in CRC. This result was confirmed by PLA.

These findings highlight DDR1’s key role in CRC cell migration and invasion through ECM remodeling. Furthermore, the discovery of a novel DDR1 partner offers promising insights into CRC molecular mechanisms and potential therapeutic strategies for colorectal cancer.