Perfusion bioreactor enabled fluid-derived shear stress conditions for novel bone metastatic prostate cancer testbed

Metastatic prostate cancer spreads preferentially to the bone, causing skeletal complications associated with significant morbidity and a poor prognosis, despite current therapeutic approaches. Hence, it is imperative to understand the complex metastatic cascade to develop therapeutic interventions for treating metastatic prostate cancer. Increasing evidence suggests the synergistic role of biochemical and biophysical cues in cancer progression at metastases. However, the mechanism underlying the crosstalk between interstitial flow-induced mechanical stimuli and prostate cancer progression at the bone microenvironment remains poorly understood. To this end, we have developed a three-dimensional (3D) in vitro dynamic model of prostate cancer bone metastasis using perfusion bioreactor and compared our results with static conditions to delineate the role of flow-induced shear stress on prostate cancer progression at metastases. We observed an increase in human mesenchymal stem cell (hMSCs) proliferation and differentiation rate under the dynamic culture. The hMSCs form cell agglutinates under static culture, whereas the hMSCs exhibited a directional alignment with broad and flattened morphology under dynamic culture. Further, the expression of mesenchymal to epithelial transition biomarkers is increased in bone metastasized prostate cancer models, and large changes are observed in the cellular and tumoroid morphologies under dynamic culture. Evaluation of cell adhesion proteins indicated that the altered cancer cell morphologies resulted from the constant force pulling due to increased E-cadherin and phosphorylated focal adhesion kinase proteins under shear stress. Overall, we report a successful 3D in vitro dynamic model to recapitulate bone metastatic prostate cancer behavior under dynamic conditions.