A bone-based 3D scaffold for investigating DLBCL lymphoma cell interactions within the microenvironment: from tumor biology to therapeutic implications

DLBCL is the most common lymphoma and accounts for approximately 30% of all non-Hodgkin lymphomas. DLBCL arises from a mature B cell with characteristics resembling centroblasts or immunoblasts, two distinct types of activated B cells. Patients with DLBCL typically present with a rapidly enlarging symptomatic mass, most usually nodal enlargement in the neck or abdomen. About 60% of patients will present with advanced stage DLBCL, with bone marrow involvement in up to 30% of cases. The standard therapeutic treatment for DLBCL patients involves immunochemotherapy with the R-CHOP regimen (Rituximab, Cyclophosphamide, Doxorubicin, Vincristine, and Prednisone). Over the past ten years, the discovery of novel therapeutic approaches has greatly increased the armamentarium for treating lymphoma patients, yet about 30% of patients experience recurrence or suffer from refractory DLBCL. The presence of bone marrow involvement has been consistently identified among negative prognostic factors. In this regard, intratumor heterogeneity in DLBCL is significantly influenced by the interaction of tumour cells with the microenvironment, which may have a massive impact on tumour cell biology and affect prognostically significant parameters. Within this biological setting, neoplastic cells get in touch not only with the extracellular matrix (ECM) but also with bone marrow mesenchymal stromal cells (BM-MSC) which have been reported to show anti-inflammatory and immunosuppressive properties that can be exploited by tumour cells to develop immune escape strategies. These complex interactions play a major role in DLBCL neoplastic cell progression and drug resistance. In order to address this issue, developing reliable in-vitro models that recapitulate the tumour microenvironment is crucial for studying DLBCL biology and evaluating potential therapeutic strategies. From an experimental point of view, two-dimensional (2D) systems have been traditionally employed to evaluate the intricate relationship between the microenvironment and lymphoma cells. However, they represent very simplistic platforms that fail to accurately replicate this complex biological setting. Therefore, three-dimensional (3D) in-vitro models have emerged as valuable tools for mimicking the physiological tumour microenvironment, enabling a deeper comprehension of cell-cell and cell-ECM interactions, thus facilitating the investigation of DLBCL pathogenesis. The main aim of this thesis project is to exploit a bone-based 3D scaffold, able to recapitulate the native biochemical and biophysical traits of the bone marrow compartment, in combination with human primary MSC cells and DLBCL lymphoma cells, as a promising research tool to gain novel insights into tumour biology and therapeutic implications.