Single cell genome sequencing of murine and human leukemia cells to identify copy number variations in individual cells

Chromosome instability (CIN) leads to aneuploidy, a state in which cells have abnormal numbers of chromosomes affecting two out of three cancers. Continuous CIN in murine T-cells was previously shown to dramatically accelerate lymphomagenesis in a p53-deficient background. Despite the predicted ongoing CIN in our mouse model, we observed whole chromosome copy number changes that affected all lymphoma cells, suggesting that CIN is somehow suppressed in the aneuploid lymphomas or that selection for frequently lost/gained chromosomes outcompetes the CIN-imposed missegregation. To distinguish between these explanations and to examine karyotype dynamics in CIN lymphoma, we used a newly developed single-cell whole genome-sequencing (scWGS) platform that provides a complete and unbiased overview of copy number variations (CNV) in individual cells. In this study we applied single cell whole genome sequencing (scWGS) to map and quantify karyotype heterogeneity in primary mouse lymphoma and human leukaemia samples. We used cohorts of Mps1f/f; Lck-Cre+, Mps1f/f; p53f/f; Lck-Cre+ and Mps1f/f; p53f/+; Lck-Cre+ mice, and Lck-Cre- mice as controls. Mice were sacrificed when exhibiting signs of lymphoma (10-14 weeks of age, typically dyspnoea due to an enlarged thymus), thymuses were harvested, and primary T-ALL single cell suspensions were frozen for subsequent single cell sequencing analysis.