Metabolic and mechanical regulation of tumor cell extravasation in metastasis: Insights from a human microphysiological model

Introduction: : Metastasis remains a difficult challenge in cancer treatment, particularly in its advanced stages. As tumor cells disseminate from the primary site, they encounter severe metabolic stressors such as hypoxia, acidosis, and nutrient deprivation. Recent studies reveal that exposure to these challenges triggers cellular reprogramming, augmenting metastatic potential and instilling metabolic memory. However, the precise mechanisms underlying metastatic resilience, especially the intricate interplay between metabolism, cellular mechanics, and migratory behavior, remain elusive. We hypothesize that metabolic deprivation enhances the mechanical resilience of tumor cells, facilitating their survival in circulation and their colonization.

Materials and

Methods: : In this work we employed innovative in vitro technologies and in vivo models to probe the novel axis connecting tumor metabolism, mechano-adaptation, and cell survival during early organ colonization. We used a microphysiological system that recapitulates blood vessel architecture using co-cultured human endothelial cells and lung fibroblasts. This platform enables modeling of tumor cell movement through blood vessels during metastasis, allowing for high-resolution imaging of cancer cell-vessel interactions, extravasation, and subsequent outgrowth. We complemented these in vitro studies with mouse models to investigate the impact of metabolic deprivation on arterial colonization across various organs. Using these complementary approaches, we explored how tumor cells adapt to metabolic stress and hemodynamic forces, enhancing their metastatic capabilities. Additionally, we investigated potential interventions by targeting key metabolic pathways and the RhoA/ROCK signaling axis.

Results, Conclusions, and Discussions:: Our findings revealed that metabolic stress induces a mechanically robust phenotype in MDA-MB-231 tumor cells by increasing RhoA activation, which enhances their circulatory survival and resistance to shear forces prior to extravasation. This mechanical adaptation reduces shear stress-induced fragmentation, ultimately leading to increased post-extravasation proliferation of metabolically deprived tumor cells, as confirmed in our in vivo studies in mouse models. To explore therapeutic interventions, we targeted key metabolic pathways and the RhoA/ROCK signaling axis within our in vitro system. Mechanistically, we discovered that inhibiting RhoA/ROCK signaling following metabolic stress disrupted this protective adaptation: tumor cells showed increased vascular interactions and arrest, and became more susceptible to shear stress-induced fragmentation during circulation. This increased vulnerability led to decreased tumor cell proliferation post-extravasation. These findings provide crucial insights into the metastatic process, from primary tumor to distant organ colonization, potentially revealing new therapeutic targets for combating cancer metastasis. Our research highlights the importance of considering metabolic adaptations in developing strategies to prevent and treat metastatic disease.

Acknowledgements and/or References (Optional):: Co-authors: Billy S. Hill², Maria Parlani², Peter Friedl² and Roger D. Kamm¹*
¹Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
²Department of Cell Biology, Radboud University Medical Center, Nijmegen, the Netherlands
*Last author