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Investigation of the Transcriptional Role of a RUNX1 Intronic Silencer by CRISPR/Cas9 Ribonucleoprotein in Acute Myeloid Leukemia Cells
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Investigation of the Transcriptional Role of a RUNX1 Intronic Silencer by CRISPR/Cas9 Ribonucleoprotein in Acute Myeloid Leukemia Cells

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Runt-related transcription factor RUNX3 is a target of MDM2-mediated ubiquitination

Xin-Zi Chi1, Jiyeon Kim, Yong-Hee Lee

  • 1Departments of Biochemistry, College of Medicine, Institute of Tumor Research, Chungbuk National University, Cheongju, South Korea.

Cancer Research
|October 8, 2009
PubMed

Insights

Ras activation stabilizes the tumor suppressor RUNX3 via the p14(ARF)-MDM2 pathway, preventing oncogenic damage. This mechanism highlights RUNX3 and p53 as key responders in cellular defense against abnormal oncogene activation.

Area of Science:

  • Molecular Biology
  • Oncology
  • Cellular Signaling

Background:

  • The p14(ARF)-MDM2-p53 pathway is crucial for cellular defense against oncogenic stimuli like Ras and Myc.
  • Ras activation can precede p53 inactivation in cancer development, suggesting alternative surveillance mechanisms.

Purpose of the Study:

  • To investigate the role of Ras activation in stabilizing the tumor suppressor RUNX3.
  • To elucidate the mechanism by which the p14(ARF)-MDM2 pathway regulates RUNX3.

Main Methods:

  • Investigated the interaction between RUNX3 and MDM2 using biochemical assays.
  • Analyzed the effect of MDM2 on RUNX3 transcriptional activity and stability.
  • Examined RUNX3 ubiquitination and degradation mediated by MDM2.

Main Results:

  • Ras activation stabilizes RUNX3 through the p14(ARF)-MDM2 pathway.
  • RUNX3 directly binds to MDM2 via its Runt-related DNA-binding domain.
  • MDM2 inhibits RUNX3 transcriptional activity and promotes its ubiquitination and degradation.

Conclusions:

  • RUNX3 is a novel substrate of the p14(ARF)-MDM2 surveillance pathway.
  • Both RUNX3 and p53 act as key responders to oncogenic stress, safeguarding against uncontrolled cell proliferation.

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