Dottorato in INNOVATION IN IMMUNO-MEDIATED AND HEMATOLOGICAL DISORDERS

Titolo della tesi: Precision medicine in hemato-oncology: from tumor molecular features to endothelial-leukemia models to predict outcome and drug sensitivity.

Hematopoietic neoplasms display heterogeneous features in terms of cell of origin, clonal architecture and interaction with the environment. Persistence of residual minimal residual disease (MRD) cells and dissemination into distant secluded compartments remain undefeated cancer hallmarks favoring the emergence of resistant/chemo-refractory clones, usually associated to a fatal outcome. To address these issues, we focused on few main points: 1) characterizing the molecular features of malignant hematopoietic cells; 2) identifying patient-specific predictors of outcome; 3) testing tumour cells sensitivity to multiple compounds, using drug screening approaches in vitro and pre-clinical trials in vivo; 4) investigating the interplay between tumour and stromal cells. Two leukemic entities were analysed: i) acute myeloid leukemia (AML) and ii) T-cell acute lymphoblastic leukemia (T-ALL). For the first part, we focused on the molecular dissection of AML bearing mutations in the NPM1 gene, including a clonal evolution analysis from diagnosis to complete molecular remission (CMR) and, eventually, relapse. This allowed to identify molecular predictors of response to therapy and clinical outcome, and to pinpoint a specific subpopulation of MRD+ patients with a higher risk of experiencing relapse and death which could benefit from earlier and alternative therapeutic intervention aimed at eradicating this MRD+ state. The second part focused on the generation of a Patient-derived Tumour Xenograft (PDTX) library of T-ALL patients, on their phenotypical and molecular characterization, followed by the implementation of in vitro/in vivo therapeutic approaches aimed at identifying novel druggable targets and liabilities. We also characterized endothelial cells as supportive stromal elements able to sustain survival of T-ALL tumour cells in vitro and rescue them from toxicity under selective compounds. Single-cell RNA sequencing was implemented to provide a mechanistic overview on the crosstalk between the EC and T-ALL compartments. Overall, both projects propose the implementation of novel translational tools to achieve precision medicine, intended as a personalized approach tailored on the patients’ specific features with the ultimate goal to reach disease eradication.