Lmo2 expression defines tumor cell identity during T-cell leukemogenesis

The impact of LMO2 expression on cell lineage decisions during T-cell leukemogenesis remains largely elusive. Using genetic lineage tracing, we have explored the potential of LMO2 in dictating a T-cell malignant phenotype. We first initiated LMO2 expression in hematopoietic stem/progenitor cells and maintained its expression in all hematopoietic cells. These mice develop exclusively aggressive human-like T-ALL. In order to uncover a potential exclusive reprogramming effect of LMO2 in murine hematopoietic stem/progenitor cells, we next showed that transient LMO2 expression is sufficient for oncogenic function and induction of T-ALL. The resulting T-ALLs lacked LMO2 and its target-gene expression, and histologically, transcriptionally, and genetically similar to human LMO2-driven T-ALL. We next found that during T-ALL development, secondary genomic alterations take place within the thymus. However, the permissiveness for development of T-ALL seems to be associated with wider windows of differentiation than previously appreciated. Restricted Cre-mediated activation of Lmo2 at different stages of B-cell development induces systematically and unexpectedly T-ALL that closely resembled those of their natural counterparts. Together, these results provide a novel paradigm for the generation of tumor T cells through reprogramming in vivo and could be relevant to improve the response of T-ALL to current therapies.

Source: EMBO Journal - July 13, 2018 Category: Molecular Biology Authors: Garcia-Ramirez, I., Bhatia, S., Rodriguez-Hernandez, G., Gonzalez-Herrero, I., Walter, C., Gonzalez de Tena-Davila, S., Parvin, S., Haas, O., Woessmann, W., Stanulla, M., Schrappe, M., Dugas, M., Natkunam, Y., Orfao, A., Dominguez, V., Pintado, B., Blanco Tags: Cancer, Development & Differentiation, Immunology Articles Source Type: research