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Down-regulation of K-ras and H-ras in human brain gliomas

Rena Lymbouridou1, Giannoula Soufla1, Anthoula M Chatzinikola1

  • 1Department of Virology, Faculty of Medicine, Medical School, University of Crete, P.O. Box 1527, Heraklion 710 03, Crete, Greece.

European Journal of Cancer (Oxford, England : 1990)
|January 31, 2009
PubMed

Insights

Ras genes, crucial for cell growth, show reduced K- and H-ras mRNA in glioblastomas. This transcriptional down-regulation suggests their involvement in brain tumor development.

Area of Science:

  • Oncology
  • Molecular Biology
  • Neuroscience

Background:

  • Ras genes are key regulators of cell growth and transformation.
  • Their role in human brain tumors remains underexplored.
  • Investigating Ras gene profiles offers insights into brain carcinogenesis.

Purpose of the Study:

  • To analyze the mutational, mRNA, and protein expression of K-, H-, and N-ras genes in human brain tumors.
  • To determine the correlation between Ras gene expression and glioblastoma multiforme.
  • To elucidate the involvement of Ras genes in brain malignant transformation.

Main Methods:

  • Real-time RT-PCR for K-, H-, and N-ras transcript levels.
  • PCR-restriction fragment length polymorphism (RFLP) and direct sequencing for mutational analysis.
  • Western blot analysis for p21 protein expression.

Main Results:

  • Significantly lower K- and H-ras mRNA levels were observed in glioblastoma multiforme compared to normal brain tissue (P < 10(-4)).
  • Two K-ras mutations were identified in codons 16 and 26.
  • K-ras and H-ras mRNA down-regulation was not linked to patient survival.
  • K-ras expression positively correlated with H-ras in glioblastomas.
  • p21 protein was undetectable in all analyzed samples.

Conclusions:

  • Transcriptional down-regulation of K- and H-ras genes is implicated in malignant transformation of the brain.
  • N-ras appears to play a lesser role in brain carcinogenesis.
  • Further research into Ras gene regulation in brain tumors is warranted.

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