TOX Regulates Growth, DNA Repair, and Genomic Instability in T-cell Acute Lymphoblastic Leukemia

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive cancer originating from thymocytes.
• The high mobility group box protein TOX has been identified as a key factor in T-ALL development.

Purpose of the Study:

• To investigate the role of TOX as an oncogenic driver in T-ALL.
• To elucidate the molecular mechanisms by which TOX contributes to T-ALL initiation and progression.

Main Methods:

• Zebrafish transgenic screens to identify collaborating oncogenic drivers.
• Functional analyses including xenograft studies and molecular assays.
• Assessment of DNA repair pathway involvement, specifically nonhomologous end joining (NHEJ).

Main Results:

• TOX accelerates T-ALL onset by expanding the initial pool of transformed clones and increasing genomic instability.
• TOX is highly expressed in human T-ALL and is crucial for leukemic cell proliferation and growth.
• TOX directly binds to KU70/80, inhibiting their recruitment to DNA breaks and suppressing NHEJ repair.

Conclusions:

• TOX plays a significant role in T-ALL initiation and maintenance by impairing NHEJ repair and elevating genomic instability.
• TOX acts as a dominant oncogenic driver in a substantial proportion of human T-ALL cases.
• Targeting TOX may represent a promising therapeutic strategy for T-ALL.