Phosphorescence-based O₂ sensing reveals size-dependent survival and motility of metastatic prostate cancer cells in self-generated hypoxia

Cancer cells in solid tumors experience hypoxia, a condition of low O₂ concentration, since their O₂ demand exceeds the supply from the surrounding vasculature. However, how these cells adapt to hypoxia requires further elucidation. Here, we use a transparent phosphorescent thin film to visualize the self-generated hypoxia field of prostate cancer cells and quantify local O₂ consumption rates, measured locally as the Laplacian of the O₂ field. Single-cell tracking on steep O₂ gradients revealed that larger cells exhibit higher motility and moderate migration bias toward O₂-rich regions. Termination of hypoxia before cessation of O₂ consumption shifted cell distributions to larger sizes, whereas prolonged hypoxia induced apoptosis, producing cell populations of smaller areas post-hypoxia. Such resilience to hypoxia was absent for noncancerous fibroblasts. Our findings suggest that larger PC3 cells have enhanced metabolic fitness under hypoxia, identifying these cells as potential targets of cancer therapy.