MYC-dependent recruitment of RUNX1 and GATA2 on the SET oncogene promoter enhances PP2A inactivation in acute myeloid leukemia

Abstract

The SET (I2PP2A) oncoprotein is a potent inhibitor of protein phosphatase 2A (PP2A) that regulates many cell processes and important signaling pathways. Despite the importance of SET overexpression and its prognostic impact in both hematologic and solid tumors, little is known about the mechanisms involved in its transcriptional regulation. In this report, we define the minimal promoter region of the SET gene, and identify a novel multi-protein transcription complex, composed of MYC, SP1, RUNX1 and GATA2, which activates SET expression in AML. The role of MYC is crucial, since it increases the expression of the other three transcription factors of the complex, and supports their recruitment to the promoter of SET. These data shed light on a new regulatory mechanism in cancer, in addition to the already known PP2A-MYC and SET-PP2A. Besides, we show that there is a significant positive correlation between the expression of SET and MYC, RUNX1, and GATA2 in AML patients, which further endorses our results. Altogether, this study opens new directions for understanding the mechanisms that lead to SET overexpression, and demonstrates that MYC, SP1, RUNX1 and GATA2 are key transcriptional regulators of SET expression in AML.

Zinc Finger and X-Linked Factor (ZFX) Binds to Human SET Transcript 2 Promoter and Transactivates SET Expression

“…However, reporter assay showed that Sp1 overexpression failed to impact the transcript 2 promoter activity. This is in a sharp contrast to the transcript 1 promoter that was reported to be activated by Sp1 in HEK 293, HeLa, and Acute Myeloid Leukemia (AML) cells HL-60 and HEL [21,22]. Such a discrepancy points to the distinct transcriptional regulation between the two SET transcripts.…”

“…Quantitatively, the expression levels of transcript 2 tend to be more stable than those of transcript 1 [2]. Several studies have concentrated on the transcriptional regulation of transcript 1, and found Sp1 and NF-κB to be the major factors regulating transcript 1 promoter activity [19,21,22]. However, the regulation of SET transcript 2 promoter remains to be a knowledge gap.…”

The Chromatin Assembly Factor Complex 1 (CAF1) and 5-Azacytidine (5-AzaC) Affect Cell Motility in Src-transformed Human Epithelial Cells

“…Primary antibodies used for immunoblotting and DNA dot blot were anti-phospho-Src (Y419, Cell Signaling Technology), anti-α-tubulin (Sigma), anti-lamin B1 (Abcam), anti-histone H3 (Cell Signaling Technology), anti-p150 (Cell Signaling Technology), anti-p60 (Bethyl Laboratory), anti-GAPDH (Abcam), anti-E-cadherin (Cell Signaling Technology), anti-β-catenin (Cell Signaling Technology), anti-claudin (Cell Signaling Technology), anti-snail1 (Cell Signaling Technology), anti-snail2 (Cell Signaling Technology), anti-vimentin (Cell Signaling Technology), anti-GFP (Roche), and anti-methylcytidine (Abcam) antibodies. Immunoprecipitations were performed as previously described (36). In brief, whole cellular extracts were prepared in co-immunoprecipitation buffer (PBS containing 0.5% Triton X-100, 1 m m EDTA, 100 m m sodium orthovanadate, 0.25 m m PMSF, complete protease inhibitor (Roche)).…”

Zinc Finger and X-Linked Factor (ZFX) Binds to Human SET Transcript 2 Promoter and Transactivates SET Expression

“…However, reporter assay showed that Sp1 overexpression failed to impact the transcript 2 promoter activity. This is a sharp contrast to the transcript 1 promoter that was reported to be activated by Sp1 in HEK 293, HeLa and Acute Myeloid Leukemia (AML) cells HL-60 and HEL [21,22]. Such a discrepancy points to the distinct transcriptional regulation between the two SET transcripts.…”

“…Quantitatively, the expression levels of transcript 2 tend to be more stable than those of transcript 1 [2]. Several studies have concentrated on the transcriptional regulation of transcript 1, and found Sp1 and NFkB to be the transcription factors regulating transcript 1 promoter activity [19,21,22]. However, the regulation of SET transcript 2 promoter remains to be a knowledge gap.…”