Abstract P74: Poly-Aneuploid Prostate Cancer Cells Exhibit Enhanced HIF-1α, RhoA-Mediated Motility and Aerotaxis Under Hypoxia

Abstract

While metastasis accounts for the majority of cancer-related deaths, the mechanisms by which rare subpopulations of cancer cells complete the metastatic cascade remain poorly understood. Emerging evidence implicates poly-aneuploid cancer cells (PACCs), a subpopulation that arises via endoreplication in response to environmental stressors such as hypoxia, as potential drivers of metastasis due to their enhanced survival and regenerative capabilities. However, the mechanisms by which these cells acquire this heightened metastatic potential remain unclear. In this study, we show that prostate cancer-derived PACCs possess qualities that predict the successful completion of invasion and intravasation, which are critical steps of the metastatic cascade. Using time-lapse fluorescence microscopy and single-cell tracking under hypoxia, we found that PACCs traveled significantly greater net and total distances compared to non-PACCs, suggesting an enhanced migratory capacity and a greater potential to locally invade surrounding tissue. Analysis of PACC trajectories revealed a strong Parallel Forward Migration Index aligned with increasing oxygen concentration, which is consistent with aerotactic migration and predictive of entry into the oxygen-rich bloodstream during metastasis. To identify molecular drivers of this behavior, we examined the roles of HIF-1α and RhoA, known regulators of hypoxic survival and cytoskeletal remodeling, respectively. Using siRNA-mediated knockdown and single-cell tracking under hypoxia, we found that hypoxic prostate cancer cells – particularly PACCs – exhibited increased motility and aerotaxis in a HIF-1α and RhoA-dependent manner. Notably, RhoA expression was also suppressed upon HIF-1α inhibition, suggesting HIF-1α-dependent regulation of RhoA. Based on these findings, we propose a potential mechanism (HIF-1α → RhoA → motility/aerotaxis) that enables PACCs to escape hypoxic tumor cores, invade the surrounding tissue, and enter oxygen-rich vasculature. Altogether, these results suggest that PACCs are a uniquely invasive subpopulation and offer new insight into the molecular basis of prostate cancer metastasis, with implications for the development of targeted anti-metastatic therapies.