Molecular analysis of rare cytogenetic abnormalities in chronic lymphocytic leukemiafrom genomic alterations to metabolic reprogramming

Resumo

Cytogenetic abnormalities are a hallmark of chronic lymphocytic leukemia (CLL), and they have been correlated with different outcomes, which has made it possible to classify patients into different risk subgroups. In the last decade, next-generation sequencing (NGS) techniques have allowed the identification of a plethora of genetic mutations and copy number variations in a large number of CLL drivers, contributing to a better comprehension of the CLL molecular landscape and to refine CLL prognosis. The less frequent cytogenetic abnormalities (6q deletion, 14q deletions and 14q translocations) have been suggested to impact prognosis, although there is still some controversy among studies. Moreover, the biological implications of these alterations are largely unexplored in CLL. In order to decipher the clinical and biological effects of rare cytogenetic alterations in CLL pathogenesis, progression and therapy response, different approaches were used in this thesis. The molecular characterization of patients harboring 6q deletion, 14q deletions and 14q translocations through NGS showed distinct mutational profiles with different clinical implications within these subgroups. Remarkably, patients with 14q deletions had a high frequency of biallelic inactivation of TRAF3 gene, being an independent risk factor of prognosis. By applying CRISPR/Cas9-editing technologies, we reproduced the TRAF3 mutations reported in patients, and using transcriptomic, metabolomic and functional approaches, this work revealed the impact of these mutations on the activation of NF-kB signaling and the induction of CLL cells metabolic reprogramming, identifying new mechanisms of pathogenicity potentially targetable in CLL.