Reprogramming of MLL-AF9 leukemia cells into pluripotent stem cells

Area of Science:

• Stem Cell Biology
• Oncology
• Epigenetics

Background:

• Yamanaka factors (Oct4, Sox2, Klf4, c-Myc) induce pluripotency in somatic cells.
• Reprogramming capacity of malignant cells remains largely uncharacterized.
• Acute myeloid leukemia (AML) pathogenesis involves oncogenic drivers like MLL-AF9.

Purpose of the Study:

• To assess the reprogramming potential of primary malignant cells into induced pluripotent stem (iPS) cells.
• To investigate the interplay between oncogenic factors and reprogramming factors in MLL-driven leukemogenesis.
• To explore novel therapeutic strategies for hematopoietic malignancies.

Main Methods:

• Established a doxycycline-inducible MLL-AF9-driven AML mouse model in hematopoietic cells carrying Yamanaka factors.
• Reprogrammed leukemia cells into iPS cells upon doxycycline addition.
• Analyzed gene expression patterns using RNA-sequencing (RNA-seq).

Main Results:

• Transplantable AML cells efficiently converted into teratoma-forming and chimera-producing iPS cells.
• Chimeric mice developed spontaneous AML, indicating leukemia reinitiation from reprogrammed cells.
• Reversible gene expression patterns between leukemia and iPS cells were observed, driven by MLL-AF9.
• Evidence suggests a common leukemia-initiating cell for both iPS reprogramming and leukemia reinitiation.

Conclusions:

• MLL-AF9 oncogene and Yamanaka factors facilitate reversible reprogramming of AML cells.
• This reprogramming approach offers a platform to study oncogenic mechanisms and develop new treatments for hematologic cancers.
• The findings highlight the epigenetic plasticity in leukemogenesis and reprogramming.