A Comparative Study of Bone Marrow and Central Nervous System Microenvironment Models to Improve In Vitro Studies of Acute Lymphoblastic Leukemia

The bone marrow (BM) niche plays a critical role in the development of acute lymphoblastic leukemia (ALL), while the central nervous system (CNS) is a common site of dissemination. Existing in vitro models of childhood ALL lack complexity and fail to recapitulate the in vivo microenvironments. This study aimed to improve ALL in vitro models by integrating key elements of the BM and CNS niches. We optimized the culture medium by evaluating the impact of cytokines and human platelet lysate in medium, which significantly improved ALL cell viability (p < 0.05) with a maximum viability of 54.61% achieved. Expression of cancer-associated fibroblast (CAF) markers in human Mesenchymal Stromal Cells (hMSCs) and human Meningeal Cells (HMCs) were examined, but co-culture with primary ALL cells did not induce an increase in CAF marker expression in our stromal cells. ALL cells exhibited enhanced viability in 5% oxygen compared to 21% oxygen (p < 0.05). The final BM and CNS models demonstrated superior survival of ALL cells (p < 0.05) compared to more simple models with a maximum viability achieved of 92.25% for BM model and 92.99% for CNS. These findings indicate that mimicking BM and CNS microenvironments enhances the survival of primary ALL cells in vitro.