BCR-ABL1-positive microvesicles malignantly transform human bone marrow mesenchymal stem cells in vitro

Area of Science:

• Hematology
• Oncology
• Cell Biology

Background:

• Intercellular communication between leukemia cells and bone marrow mesenchymal stem cells (BM-MSCs) is crucial in chronic myeloid leukemia (CML).
• Microvesicles (MVs) from K562 leukemia cells carry BCR-ABL1 mRNA and can transform normal hematopoietic cells.
• The role of K562-MVs in the transformation of human BM-MSCs remains to be fully elucidated.

Purpose of the Study:

• To investigate the contribution of K562-MVs to the transformation of human BM-MSCs.
• To explore the reciprocal interaction between transformed BM-MSCs and leukemia cells.
• To assess the clinical relevance of these interactions in CML patients.

Main Methods:

• Co-culture of K562-MVs with normal human BM-MSCs.
• Analysis of BM-MSC proliferation and BCR-ABL1 expression.
• Measurement of TGF-β1 secretion by BM-MSCs.
• Confirmation of BCR-ABL1 in circulating MVs from CML patients.
• Comparison of BM-MSCs from CML patients versus normal individuals.

Main Results:

• K562-MVs integrated into BM-MSCs, enhancing their proliferation and BCR-ABL1 expression.
• K562-MVs induced TGF-β1 secretion in BM-MSCs, which in turn promoted K562 cell proliferation.
• BCR-ABL1 was detected in circulating MVs from CML patients.
• BM-MSCs from CML patients showed enhanced capacity to increase BCR-ABL1 expression, TGF-β1 secretion, and proliferation of K562 cells compared to normal BM-MSCs.

Conclusions:

• K562-MVs contribute to BM-MSC transformation, enriching understanding of leukemia-stromal cell interactions in CML.
• The reciprocal signaling pathway involving BCR-ABL1 and TGF-β1 plays a significant role in CML pathogenesis.
• Circulating MVs and patient-derived BM-MSCs offer potential biomarkers for minimal residual disease monitoring and therapeutic targets in CML.