The Role of Phenotypic Plasticity in Adaptation to Treatment and Prospective Plasticity Drivers in Hepatoblastoma

Hepatoblastoma (HB) is a paediatric liver cancer, associated with one of the lowest mutational burdens compared to other cancers. Despite this, HBs exhibit diverse phenotypes. It has been proposed that hijacking of early developmental plasticity is especially relevant to chemotherapy response in childhood cancers, however the underlying mechanisms of plasticity in HB remain poorly understood. Plasticity in HB requires investigation after treatment at a more granular temporal scale to further elucidate its role in treatment adaptation. In this work, we aim to study the role of plasticity in treatment adaptation and its underlying mechanisms by integrating heritable and expressed static DNA barcode technology with single-cell sequencing. The synergy between these approaches allows for simultaneous lineage tracing of single clones and phenotyping of single cells. We identify the phenotypic states that exist in HB preclinical models and explore the phenotypic transitions that occur following treatment, which could be important for cells to survive, persist and eventually recover. Expression and accessibility landscapes reveal prospective targets that could be markers or drivers of the plasticity which enables treatment adaptation in HB. By homing in on the clonal, transcriptomic and epigenetic dynamics post treatment, these results examine in greater detail the role of plasticity in treatment adaptation in HB.