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Published on: January 7, 2019

Mutated ras induced PLD1 gene expression through increased Sp1 transcription factor

Siqiang Gao1, Masashi Murakami, Hiromi Ito

  • 1Department of Medical Technology, Nagoya University Graduate School of Health Sciences, Nagoya, Japan.

Nagoya Journal of Medical Science
|December 10, 2009
PubMed

Insights

Mutated Ras oncogenes increase phospholipase D1 (PLD1) expression by activating the Sp1 transcription factor. This study identifies Sp1 as a key mediator in Ras-driven oncogenesis, offering potential therapeutic targets.

Area of Science:

  • Molecular Biology
  • Oncology
  • Cell Biology

Background:

  • The mechanisms linking oncogene activation to phospholipase D (PLD) activity remain unclear.
  • Oncogenic mutations, particularly in Ras, are implicated in various cancers, but their direct effects on PLD regulation need further investigation.

Purpose of the Study:

  • To elucidate the role of mutated Ras in regulating phospholipase D1 (PLD1) gene expression.
  • To identify the specific transcription factors and regulatory elements involved in Ras-mediated PLD1 activation.

Main Methods:

  • Utilized colon cancer cell lines and NIH3T3 cells with mock or mutated Ras transfection.
  • Performed 5' promoter analysis, Sp1 inhibition studies (mithramycin A, siRNA), and Sp1 overexpression experiments in Drosophila SL2 cells.
  • Employed Electrophoretic Mobility Shift Assay (EMSA) and Chromatin Immunoprecipitation (ChIP) assays.

Main Results:

  • Mutated Ras activation correlated with increased PLD1 mRNA and protein levels.
  • A specific Sp1-binding site within the PLD1 promoter was identified as crucial for Ras-induced expression.
  • Inhibition of Sp1 activity or protein levels reduced PLD1 expression and promoter activity.
  • Sp1 protein levels and its binding to the PLD1 promoter motif increased with Ras activation.

Conclusions:

  • Sp1 is a critical mediator of Ras-induced PLD1 expression.
  • Ras activation enhances PLD1 transcription through increased Sp1 binding to its promoter motif.
  • Targeting the Sp1-PLD1 interaction may offer a strategy for inhibiting oncogene-driven cancer progression.

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