Alternate VEGFA isoform expression in fibrosarcoma leads to plasticity in cellular migration and differences in sensitivity to inhibition with anti-VEGFA antibodies

Metastasis remains a primary contributor to cancer-related mortality. Elevated expression of soluble vascular endothelial growth factor A (VEGFA) isoforms is linked to increased metastatic potential and enhanced cellular plasticity in response to microenvironmental changes. To investigate the connection between VEGFA isoform expression, migration plasticity, and metastasis, we analyzed the migratory behavior of fibrosarcoma cells expressing single VEGFA isoforms within engineered microenvironments mimicking tumor-associated extracellular matrix (ECM) architectures that drive distinct migration modes. Fibrosarcoma cell lines expressing VEGFA120 or VEGFA188 were derived from embryonic (Fs120 and Fs188) or mature skin fibroblasts, ensuring comparable VEGFA isoform expression across cells of different origins. Characterization of collagen fibril diameter and organization in tumors derived from Fs120 or Fs188 cells showed that Fs120 tumors had a higher degree of fibril alignment, suggesting VEGFA120 expression may facilitate ECM remodeling to support metastasis. To simulate these different collagen fibril structures for use in migration studies in vitro , we developed 3D platforms representing aligned and randomly organized collagen fibers using electrospinning of polycaprolactone. On 2D surfaces favoring mesenchymal migration and on 3D electrospun scaffolds promoting contact-guided migration, VEGFA120- and VEGFA188-expressing cells exhibited similar migratory capacities, regardless of their origin. However, anti-VEGFA antibodies selectively inhibited the migration of VEGFA120-expressing cells on fibronectin-coated surfaces and on aligned fiber scaffolds, but not non-aligned fibers, revealing isoform-specific sensitivity to VEGFA inhibition. In conclusion, while the expression of single VEGFA isoforms does not directly alter migration plasticity, VEGFA120 expression in mouse fibrosarcomas uniquely promotes ECM reorganization in tumors and cells expressing VEGF120 show increased sensitivity to anti-VEGFA antibodies.