LAUSR

To understand how malignant tumors develop from single cells, we used long-term, time-lapse, live-cell imaging to track the dynamics of the cell membrane, nucleus, spindle, and cell cycle regulators during the development of high-grade, serous, carcinoma-derived organoids. Organoids are highly heterogeneous and include 2 major subtypes. Type-1 organoids are relatively homogeneous and develop via traditional mitosis, whereas type-2 organoids are highly heterogenous and are composed of differently sized polyploid giant cancer cells (PGCCs). Tracking the origin of PGCCs in type-2 organoids shows single cells first undergo asymmetric mitosis and nuclear fusion, followed by endoreplication, multipolar restitution mitosis, multipolar endomitosis, and karyokinesis. At the cellular level, the formation of PGCCs was associated with the formation of transient intracellular cells, termed fecundity cells. The fecundity cells underwent decellularization via the dissolution of the cell membrane, which allowed a giant nucleus to form via nuclear fusion. Different PGCCs underwent nuclear budding, decellularization, or entosis to form Russian doll-like tissue structures that facilitated rapid tumor growth and evolution. The uncoupling of nuclear augmentation from cytokinesis led to a rapid increase in the nuclear-to-cytoplasmic ratio and increased the genomic content of PGCCs, which facilitated macro-genomic evolution during tumor development. Our live-cell imaging evidence allows us to link nuclear replication and cancer evolution to the nuclear morphologies observed by pathologists under the microscope. PGCCs may be the central regulators of malignant histogenesis, cancer evolution, and physical barriers conferring resistance to immune therapy. Citation Format: Xiaoran Li, Yanping Zhong, Xudong Zhang, Anil Sood, Jinsong Liu. Spatio-temporal view of malignant histogenesis and cancer evolution via formation of polyploid giant cancer cell [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 108.