CTCF Is Essential for the Development and Maintenance of CALM-AF10-Induced Leukemia.

Area of Science:

• Hematology
• Molecular Biology
• Cancer Research

Background:

• CALM-AF10 fusion gene, resulting from t(10;11) translocation, is a driver of acute myeloid leukemia (AML) with poor prognosis.
• The CCCTC-binding factor (CTCF) is implicated in various cellular processes, but its role in CALM-AF10 AML pathogenesis is not fully understood.

Purpose of the Study:

• To investigate the role of CTCF in the development and maintenance of CALM-AF10 AML.
• To identify downstream targets of CTCF involved in CALM-AF10 AML progression.
• To evaluate the therapeutic potential of targeting CTCF-regulated pathways in CALM-AF10 AML.

Main Methods:

• In vivo studies using CALM-AF10 AML mouse models with CTCF deficiency.
• In vitro experiments involving CTCF knockout (KO) in CALM-AF10 AML cells.
• RNA sequencing (RNA-seq) and Chromatin immunoprecipitation sequencing (ChIP-seq) to analyze gene expression and epigenetic modifications.
• Gene knockdown using short hairpin RNA (shRNA) and pharmacological inhibition of Transglutaminase 2 (TGM2).

Main Results:

• CTCF deficiency significantly improved survival in CALM-AF10 AML mice.
• CTCF KO reduced colony formation and induced differentiation of CALM-AF10 AML cells.
• Transglutaminase 2 (TGM2) was identified as a key downregulated gene in CTCF KO cells.
• CTCF regulates TGM2 expression via epigenetic modifications (H3K27me3, H3K4me3, H3K27ac) at the TGM2 transcription start site.
• TGM2 knockdown or inhibition mimicked the effects of CTCF KO, reducing proliferation and promoting differentiation.

Conclusions:

• CTCF plays a critical role in both the initiation and maintenance of CALM-AF10 AML.
• CTCF regulates TGM2 expression through epigenetic mechanisms, maintaining the undifferentiated state of CALM-AF10 AML cells.
• TGM2 inhibition represents a promising therapeutic strategy for CALM-AF10 AML.