The RUNX1-ETO fusion protein trans-activates c-KIT expression by recruiting histone acetyltransferase P300 on its promoter.

Abstract

The oncoprotein RUNX1-ETO is the fusion product of t(8;21)(q22;q22) and constitutes one of the most common genetic alterations in acute myeloid leukemia (AML). Abnormal c-KIT overexpression is considered an independent negative prognostic factor for relapse and survival in t(8;21) AML patients. However, the molecular mechanism of high c-KIT expression in t(8;21) AML remains unknown. In this study, we detected RUNX1-ETO and c-KIT gene expression in AML-M2 patients and verified the overexpression of c-KIT in t(8;21) AML patients. We also found that c-KIT overexpression was a poor prognostic indicator in RUNX1-ETO positive AML patients, but not in RUNX1-ETO negative AML patients. We used the dual-luciferase and ChIP assays to demonstrate that the RUNX1-ETO protein epigenetically trans-activates c-KIT by binding to the c-KIT promoter and recruiting the histone acetyltransferase P300 to the c-KIT promoter, elucidating the mechanism of the abnormally increased c-KIT expression in t(8;21) AML patients. Moreover, pharmacological studies revealed that C646, a P300 inhibitor, could inhibit proliferation, induce apoptosis and arrest the cell cycle more effectively in RUNX1-ETO positive cells than in negative ones. The levels of c-KIT and RUNX1-ETO proteins were also decreased with C646 treatment in RUNX1-ETO positive cells. These findings suggested that P300 could be a therapeutic target and that C646 could be used as a potential treatment for RUNX1-ETO positive AML patients. Interestingly, using the dual-luciferase assay, we also found that the binding capacity of RUNX1-ETO9a, a truncated RUNX1-ETO isoform, to the c-KIT promoter was stronger than that of RUNX1-ETO, suggesting RUNX1-ETO9a as another valuable therapeutic target in t(8;21) AML.

• Authors: Guofeng Chen, Anqi Liu, Yihan Xu, Li Gao, Mengmeng Jiang, Yan Li, Na Lv, Lei Zhou, Lili Wang, Li Yu, Yonghui Li
• Journal: The FEBS journal (FEBS J) Vol. 286 Issue 5 Pg. 901-912 (03 2019) ISSN: 1742-4658 [Electronic] England
• PMID: 30637949 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2019 Federation of European Biochemical Societies.

Chemical References

• 4-(4-((5-(4,5-dimethyl-2-nitrophenyl)-2-furanyl)methylene)-4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl)benzoic acid
• Benzoates
• Nitrobenzenes
• Oncogene Proteins, Fusion
• Pyrazoles
• Pyrazolones
• RNA, Long Noncoding
• RUNX1-IT1 long non-coding RNA, human
• p300-CBP Transcription Factors
• p300-CBP-associated factor
• KIT protein, human
• Proto-Oncogene Proteins c-kit

Topics

• Benzoates (pharmacology)
• Cell Line
• Chromosomes, Human, Pair 21
• Chromosomes, Human, Pair 8
• Gene Expression Regulation (drug effects, physiology)
• Humans
• Leukemia, Myeloid, Acute (genetics)
• Nitrobenzenes
• Oncogene Proteins, Fusion (genetics, physiology)
• Prognosis
• Promoter Regions, Genetic
• Proto-Oncogene Proteins c-kit (genetics)
• Pyrazoles (pharmacology)
• Pyrazolones
• RNA, Long Noncoding
• Transcriptional Activation (physiology)
• Translocation, Genetic
• p300-CBP Transcription Factors (antagonists & inhibitors, genetics, metabolism)