Mechanical Stimuli‐Induced Manipulation of Malignant Behavior in Bioprinted Cancer Microtissues via PI3K/NF‐κB Activation

Increased matrix stiffness within tumor microenvironments (TMEs) significantly influences cancer progression and gene expression, contributing to drug resistance and poor clinical outcomes. Studies demonstrate a strong correlation between nuclear factor kappa B (NF-κB) upregulation and prostate cancer malignancy. However, the mechanisms by which the mechanical stress within the TME activates NF-κB remain underexplored. This study developed a prostate cancer spheroid model using an in-bath 3D bioprinting technique. Cancer spheroids were printed within a bespoke hydrogel bath with tunable stiffness, facilitating the investigation of the relationship between mechanical cues and oncogenic behavior. Increased hydrogel stiffness promoted spheroid compaction, induction of epithelial-mesenchymal transition (EMT) and stemness programs, and elevated drug resistance. Transcriptomic analysis revealed that the phosphoinositide 3-kinase (PI3K) pathway is most enriched under mechanical stress. Findings demonstrated that increased extracellular matrix stiffness activated PI3K/NF-κB signaling through mechanotransduction. Pharmacological inhibition of PI3K suppressed NF-κB nuclear translocation and enhanced chemotherapy efficacy. The bespoke hydrogel effectively recapitulated the mechanical environment of prostate cancer, indicating the pivotal role of PI3K/NF-κB signaling in regulating prostate cancer malignancy under mechanical stimulation. This suggests a promising therapeutic avenue for improving treatment outcomes.