Cellular barcoding as a tool to investigate the clonal complexity and evolution of ALL

There remains significant controversy over the applicability of cancer stem cell models to acute lymphoblastic leukaemia. Recent data suggest that the propagating compartment undergoes a clonal evolution process, leading to the co-existence of several different subclones. We are aiming to provide a comprehensive picture of the clonal complexity and evolution of primary ALL samples engrafted into mice by individually marking leukaemia cells with heritable genetic markers. We achieve this using a barcoded lentiviral vectors, together with analysis of the lentiviral integration sites. These strategies allow us to address numerous questions, including assessing the number of clones that contribute to leukaemia following grafting into NSG mice, clonal evolution over serial transplants and changes in clonal complexity following selective pressures such as drug treatment. Our studies show a diverse pool of engrafting clones, the complexity of which changes over primary and secondary transplants.