Cycling persister clones with elevated NR2F1-mediated cholesterol biosynthesis cause chemotherapy resistance

Abstract

While a subpopulation termed cycling persisters (CPs) that is characterized by sustained proliferation, even under chemotherapy drug exposure, contributes more directly to tumor relapse, the molecular basis for the emergence of CPs has been unclear. Here, we used the human tongue cancer organoid (TCO) library to continuously track the in vitro fate of individual cancer cell clones during and after chemotherapy exposure using time-lapse imaging. Among the heterogeneous clones, we identified CPs that formed larger clusters than the others, which barely grew and remained small (non-CPs). Using differences in cell cluster size as an indicator, thousands of CP and non-CP clones were directly sampled from 3D matrix organoid cultures and were analyzed. Notably, tumor-intrinsic interferon (IFN) signaling and hypoxic pathways were inactivated, whereas the NR2F1-mediated cholesterol biosynthesis pathway was distinctly activated in CPs compared to non-CPs. Indeed, inhibiting cholesterol biosynthesis with simvastatin significantly suppressed the appearance of CP clones, showing that elevated cholesterol biosynthesis is essential for the emergence of CPs. These findings suggest that clonal-level variations in the intensity of these signaling pathways determine the fate of individual tumor cells exposed to chemotherapeutic agents, which may provide insights into cancer relapse mechanisms and identify potential molecular targets of CPs.