• leucemia linfatica cronica
• chronic lymphocytic leukaemia

Despite recent therapeutic improvements, Chronic Lymphocytic Leukemia (CLL) remains an incurable disease with a highly variable clinical course. The recent advancement in sequencing technologies has remarkably improved this characterization allowing to carefully examine the emergence of clonal evolution in CLL and to address its impact on the clinical outcome of the disease. Alteration in key genes such as P53, SF3B1 and ATM have been identified and their clinical implication clearly established. Among them, mutations affecting NOTCH1 are the most common and are associated with a poor prognosis. Additionally, NOTCH2 is also relevant in CLL pathogenesis as it is associated with increased cell viability and drug response. Nevertheless, the underlying molecular mechanisms for NOTCH signalling in CLL are still mostly unknown. Here, using a co-culture system that mimics the extrinsic signals that malignant cells encounter in the lymph node microenvironment we investigated the different roles of NOTCH1 and NOTCH2 in CLL and Mantle cell lymphoma (MCL). Additionally, stimulation of the receptors translates into a broad transcriptional gene activation among which the c-MYC oncogene plays a major role.
Historically primary CLL cells have been extremely difficult to modify genetically and therefore the analyses of clonal and sub-clonal mutations in CLL have been limited to correlative studies or analyses of cell lines that do not fully recapitulate the disease. To take advantage of a new protocol of gene transduction already established in the laboratory, we cloned a truncated version of the intracellular domain of NOTCH1 and NOTCH2 that mimic the mutations of PEST domain found in CLL and MCL patients. We then over-expressed these constructs into primary patient cells to understand the specific role played in these diseases. The same strategy was used also for the human c-MYC cDNA, allowing us to understand that c-MYC leads to substantial cell proliferation of primary CLL cells, and that NOTCH1 acts independently of c-MYC to regulates immune-escape from T cells.