Mutant IL7R collaborates with MYC to induce T-cell acute lymphoblastic leukemia

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• T-cell acute lymphoblastic leukemia (T-ALL) is a severe pediatric cancer.
• Gain-of-function mutations in the IL-7 receptor α chain (IL-7Rα), encoded by IL7R, are found in 10% of T-ALL patients.
• The sufficiency of IL-7Rα mutations for T-cell precursor transformation and cooperating genes in leukemogenesis are not well understood.

Purpose of the Study:

• To investigate if IL-7Rα gain-of-function mutations alone can induce T-ALL.
• To identify genes that cooperate with IL7R mutations in driving leukemogenesis.
• To elucidate the mechanisms by which IL-7Rα mutations contribute to T-ALL.

Main Methods:

• Stable transgenic zebrafish models were utilized to study T-ALL development.
• Gene expression analysis and transcriptional activation studies were performed.
• Limiting-dilution cell transplantation assays were employed to assess leukemia-propagating potential.

Main Results:

• Mutant IL7R alone induced long-latency T-ALL in zebrafish, associated with MYC transcriptional activation.
• Mutant IL7R collaborated with Myc to cause early-onset T-ALL.
• Co-expression of mutant IL7R and Myc activated STAT5 and AKT pathways, reduced apoptosis, and accelerated tumor formation in transplanted zebrafish.
• Activated IL-7R signaling increased the frequency of leukemia-propagating cells.

Conclusions:

• Mutant IL-7Rα cooperates synergistically with Myc to drive T-ALL development.
• Mutant IL-7Rα enriches for leukemia-propagating cells, contributing to disease progression.
• This study provides insights into the molecular mechanisms underlying T-ALL driven by IL-7Rα mutations.