Non-canonical Wnt/Ror2 signaling status regulates cell-matrix crosstalk to prompt directional tumor cell invasion and dissemination in breast cancer

Cancer deaths largely result from metastasis, the spread of cancer from the primary tumor to distant organs. Initial steps of metastasis require that tumor cells invade into the surrounding tissue and gain access to blood or lymphatic vessels. Such invasion is reliant on a balance of cell-cell and cell-matrix cues within the microenvironment of the tumor, yet factors regulating such interactions for invading tumor cells remain elusive in the context of cancer. We demonstrate that the noncanonical Wnt receptor, Ror2, in mammary tumor models of Tripe Negative Breast Cancer, regulates the composition and remodeling of the tumor stroma, where Ror2-depletion prompts directional tumor cell invasion and coordinated ECM production at the leading edge of tumor cell movement. By RNA sequencing, we discovered that tumor organoids specifically harbor actin cytoskeleton, cell adhesion, and collagen cross-linking gene expression programs when Wnt/Ror2 signaling is impaired. Interestingly, Ror2 depletion resulted in the downregulation of E-cadherin in tumor organoids, particularly at invading tumor cell protrusions within the surrounding ECM. Spatially, we identified the upregulation and redistribution of integrin receptors, particularly integrin-α5 in Ror2-deficient tumor organoids, accompanied by the simultaneous production of a provisional Fibronectin matrix, a requisite component of the ECM, ligand for integrin α5, and mediator of collagen assembly and organization. Along with altered ECM architecture, Ror2 loss reshaped the topology of integrin and FAK activation within primary tumors, suggesting an important physiological function for Ror2 in shaping both signaling and ECM architecture during tumor progression. Blocking either integrin or FAK, a downstream mediator of integrin-mediated signal transduction, abrogated the enhanced migration observed upon Ror2 loss. These results suggest that Ror2 status within a tumor can significantly impact adhesive vs. migratory states in breast cancer and provide a novel mechanism where Wnt/Ror2 shapes not only tumor cell composition, but also reciprocal cell-ECM interactions prompting directional and collaborative tumor cell transit during cancer progression. ### Competing Interest Statement The authors have declared no competing interest.