Spleen plays a major role in DLL4-driven acute T-cell lymphoblastic leukemia

Area of Science:

• Hematology
• Immunology
• Molecular Biology

Background:

• The Notch pathway is crucial in T-cell acute lymphoblastic leukemia (T-ALL).
• The role of Notch ligands, such as delta-like 4 (DLL4), in T-ALL pathogenesis is not fully understood.
• DLL4 is implicated in various cancers, making it a potential therapeutic target.

Purpose of the Study:

• To investigate the role of DLL4 in T-ALL development and progression.
• To evaluate the therapeutic efficacy of targeting DLL4 in T-ALL models.
• To identify the specific organ responsible for promoting DLL4-driven T-ALL.

Main Methods:

• Utilized a genetic mouse model of DLL4-driven T-ALL.
• Performed thymectomies and splenectomies in mouse models.
• Tested patient-derived T-ALL (PDTALL) models in vitro and in vivo.
• Administered demcizumab, a DLL4-blocking antibody, to PDTALL models.

Main Results:

• Spleen removal abrogated T-ALL development in the DLL4-driven mouse model.
• The spleen, not the thymus, promoted the accumulation of CD4+CD8+ T cells preceding T-ALL onset.
• DLL4 expression was identified in a subset of human T-ALL patients.
• Demcizumab treatment demonstrated therapeutic effects comparable to global Notch inhibition in a DLL4-positive PDTALL model.

Conclusions:

• DLL4 expressed by leukemic cells can drive Notch pathway activity in T-ALL.
• The spleen plays a significant role in the development of DLL4-driven T-ALL.
• Targeting DLL4 with antibodies like demcizumab represents a promising therapeutic strategy for T-ALL.