Reconfiguration of the Microtubule Network and Dynamics in Hypoxic Cancer Cells

Cancer cells within solid tumors adapt to hypoxic microenvironments caused by vasculature disruption. Oxygen deprivation induces changes in cell signaling and metabolism, leading to increased resistance to treatment and elevated metastasis. The microtubule network plays a crucial role in cell signaling and migration; however, few studies have investigated its time-dependent dynamics in live hypoxic cancer cells. Here, we applied advanced optical microscopy to study microtubule dynamics and their relationships with local mitochondrial activities and cell migration in hypoxia. Our results show that hypoxia exposure does not significantly alter the speed of microtubule polymerization but induces the formation of microtubule-rich protrusions. This protrusion formation largely requires glycolytic activity and the availability of nutrients. Furthermore, mitochondria relocation into these protrusions was found, along with localized expression of nucleoside-diphosphate kinase. Using real-time precision opto-control technology, we selectively disrupted mitochondrial function within the protrusions, which led to reduced local microtubule polymerization, highlighting the role of site-specific mitochondrial activity in supporting local microtubule dynamics. Moreover, hypoxia-induced microtubule-rich protrusions can be correlated with cancer cell migration. Together, these findings reveal how hypoxia reorganizes microtubules and mitochondria in cancer cells, how localized mitochondrial activity regulates microtubule polymerization, and how these changes influence cancer cell migration under hypoxia.