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Different patterns of gene expression in ras-resistant and ras-sensitive cells

A B Tuck1, S M Wilson, R Khokha

  • 1London Regional Cancer Centre, Ontario, Canada.

Journal of the National Cancer Institute
|April 3, 1991
PubMed

Insights

Ras gene expression impacts cell malignancy differently. NIH 3T3 cells become metastatic with ras, while LTA cells show resistance, suggesting distinct gene expression patterns influence cancer progression.

Area of Science:

  • Molecular Biology
  • Cancer Research
  • Cell Biology

Background:

  • Nontumorigenic NIH 3T3 cells gain tumorigenicity and metastasis with activated ras.
  • Tumorigenic LTA cells exhibit natural resistance to ras-induced malignancy.
  • Investigating differential gene expression is key to understanding ras resistance.

Purpose of the Study:

  • To explore mechanisms of natural ras resistance by comparing gene expression in ras-sensitive NIH 3T3 and ras-resistant LTA cells.
  • To analyze the impact of ras transfection on genes involved in metastasis, invasion, and cell adhesion.
  • To correlate gene expression patterns with cellular malignancy and invasiveness.

Main Methods:

  • Compared gene expression patterns of jun, fos, retinoblastoma (Rb), major excreted protein (MEP), tissue inhibitor of metalloproteinases (TIMP), and secreted phosphoprotein 1 (SPP1) in LTA and NIH 3T3 cells.
  • Utilized transfection with activated T24-H-ras to induce expression.
  • Performed enzymogram assays for gelatinase activity and in vitro chemoinvasiveness assays.

Main Results:

  • Distinct basal and ras-induced gene expression differences were observed between LTA and NIH 3T3 cells.
  • Ras transfection upregulated MEP and downregulated TIMP in NIH 3T3 cells, while LTA cells showed intermediate MEP and high TIMP, largely unaffected by ras.
  • SPP1 was induced by ras in NIH 3T3 cells but repressed in LTA cells. NIH 3T3 cells showed increased gelatinase activity and chemoinvasiveness with ras, unlike LTA cells.

Conclusions:

  • Differential expression of genes including MEP, TIMP, and SPP1 contributes to ras responsiveness in NIH 3T3 cells.
  • These gene expression differences are believed to underlie the natural ras resistance observed in LTA cells.
  • The study highlights distinct molecular mechanisms governing ras-induced metastatic progression and cellular resistance.

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