Cancer-associated fibroblasts mediate cancer progression and remodel the tumouroid stroma.

Background: Cancer-associated fibroblasts (CAFs) are highly differentiated and heterogeneous cancer-stromal cells that promote tumour growth, angiogenesis and matrix remodelling.
Methods: We utilised an adapted version of a previously developed 3D in vitro model of colorectal cancer, composed of a cancer mass and the surrounding stromal compartment. We compared cancer invasion with an acellular stromal surround, a "healthy" or normal cellular stroma and a cancerous stroma. For the cancerous stroma, we incorporated six patient-derived CAF samples to study their differential effects on cancer growth, vascular network formation and remodelling.
Results: CAFs enhanced the distance and surface area of the invasive cancer mass whilst inhibiting vascular-like network formation. These processes correlated with the upregulation of hepatocyte growth factor (HGF), metallopeptidase inhibitor 1 (TIMP1) and fibulin-5 (FBLN5). Vascular remodelling of previously formed endothelial structures occurred through the disruption of complex networks, and was associated with the upregulation of vascular endothelial growth factor (VEGFA) and downregulation in vascular endothelial cadherin (VE-Cadherin).
Conclusions: These results support, within a biomimetic 3D, in vitro framework, the direct role of CAFs in promoting cancer invasion, and their key function in driving vasculogenesis and angiogenesis.