Targeting of the BLT2 in chronic myeloid leukemia inhibits leukemia stem/progenitor cell function

Area of Science:

• Hematology
• Molecular Biology
• Cancer Research

Background:

• Imatinib (a tyrosine kinase inhibitor, TKI) has improved outcomes for chronic myeloid leukemia (CML) patients.
• Resistance to TKIs, particularly in the blast phase (BP) of CML, remains a significant clinical challenge with poorly understood mechanisms.

Purpose of the Study:

• To investigate the role of BLT2 in BCR-ABL-mediated leukemogenesis and TKI resistance in CML stem/progenitor cells.
• To elucidate the involvement of the p53 signaling pathway in this process.

Main Methods:

• Quantification of BLT2 mRNA and protein levels in normal bone marrow (NBM) versus BP-CML CD34(+) stem/progenitor cells.
• Assessment of BLT2 expression in relation to BCR-ABL levels and tyrosine kinase activity.
• Evaluation of the effects of BLT2 inhibition on CML stem/progenitor cell apoptosis, proliferation, colony formation, and self-renewal.
• Combination therapy studies involving BCR-ABL TKI and BLT2 inhibition.
• Analysis of BLT2's impact on p53, Wnt, and BMP signaling pathways.

Main Results:

• BLT2 mRNA and protein levels are significantly elevated in BP-CML CD34(+) stem/progenitor cells compared to NBM, correlating with BCR-ABL expression.
• BCR-ABL knockdown or inhibition reduces BLT2 protein levels.
• BLT2 inhibition induces apoptosis, reduces proliferation, colony formation, and self-renewal capacity in CD34(+) cells from TKI-resistant BP-CML patients.
• Combining BLT2 inhibition with BCR-ABL TKI enhances the inhibitory effects on CML stem/progenitor cells.
• BLT2 activation selectively suppresses p53 signaling, without affecting Wnt or BMP pathways.

Conclusions:

• BLT2 is a novel pathway activated by BCR-ABL in CML stem/progenitor cells.
• BLT2 plays a critical role in TKI resistance in the blast phase of CML.
• BLT2 and the p53 pathway represent potential therapeutic targets for overcoming TKI resistance in CML treatment.