The core autophagy protein ATG4B is a potential biomarker and therapeutic target in CML stem/progenitor cells

Area of Science:

• * Hematology
• * Molecular Biology
• * Cancer Biology

Background:

• * Imatinib mesylate (IM) induces autophagy, crucial for survival in chronic myeloid leukemia (CML).
• * Basal autophagy differences and predictive markers in CML stem cells remain unclear.
• * Understanding CML cell autophagy is key to improving therapeutic strategies.

Purpose of the Study:

• * Investigate basal autophagy differences in CML stem/progenitor cells.
• * Determine if autophagy characteristics predict imatinib response in CML patients.
• * Identify novel therapeutic targets within the autophagy pathway.

Main Methods:

• * Differential gene expression analysis of autophagy-related genes in CD34(+) cells.
• * Protein and transcript level quantification of ATG4B, ATG5, and BECLIN-1.
• * ATG4B knockdown experiments and assessment of autophagy, cell survival, and IM sensitivity.
• * Correlation analysis between ATG4B, miR-34a, and clinical outcomes.

Main Results:

• * Key autophagy genes, particularly ATG4B, show differential expression in CML CD34(+) cells.
• * ATG4B expression levels predict response to imatinib mesylate in treatment-naïve CML patients.
• * ATG4B knockdown inhibits autophagy, reduces CML stem/progenitor cell survival, and enhances IM sensitivity.
• * ATG4B is a direct target of miR-34a, with inverse correlation observed.

Conclusions:

• * ATG4B is a potential predictive biomarker for imatinib response in CML.
• * Targeting ATG4B presents a novel therapeutic strategy for CML stem/progenitor cells.
• * Autophagy deregulation, specifically ATG4B, plays a significant role in CML pathogenesis and treatment resistance.