Prostate cancer associated fibroblasts have distinct morphomechanical features that are associated with patient outcome

Tumour development and progression reshape the physical properties of the surrounding tumour microenvironment (TME) including its biomechanical traits. This is driven by a prominent cell type in the TME, cancer associated fibroblasts (CAFs), which increases tissue stiffness via extracellular matrix deposition and remodelling. Currently, it is unclear whether there are also physical changes to CAFs at the cellular level and, if so, how they relate to patient outcome. Here we show that CAFs have distinct morphological and biomechanical features from normal fibroblasts. We examined matched, patient-derived CAFs and non-malignant prostate fibroblasts (NPFs) from 35 patients with primary prostate cancer. Morphologically, CAFs had more aligned stress fibres, and larger and more elongated nuclei, based on quantitative image analysis of confocal microscopy images. In addition, single-cell mechanical measurements using real-time deformability cytometry showed that CAFs are larger and stiffer than NPFs. These changes were consistent across patients and validated with atomic force microscopy. A combined morphomechanical score encompassing these features was significantly associated with patient outcome. In transcriptomic analyses, the score was correlated with microtubule dynamics and a myofibroblast phenotype. Importantly, we also demonstrated that morphomechanical features of prostate fibroblasts are modified by approved treatments for prostate cancer, such as docetaxel, and other small molecular inhibitors, such as axitinib. In summary, changes in cellular morphomechanical properties are a consistent feature of CAFs and associated with patient outcome. Moreover, cellular morphomechanical properties can be therapeutically targeted, potentially providing a new strategy for manipulating the TME to control cancer progression.