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Suppression of src-induced transformed phenotype by expression of tropomyosin-1

G L Prasad1, L Masuelli, M H Raj

  • 1Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA.

Oncogene
|April 20, 1999
PubMed

Insights

Tropomyosin 1 (TM1) suppresses cellular transformation by diverse oncogenes, not just ras. Overexpressing TM1 in v-src transformed cells reduced growth and anchorage-independent proliferation, confirming its role as a tumor suppressor protein.

Area of Science:

  • Cell Biology
  • Molecular Oncology
  • Cancer Research

Background:

  • Suppression of high molecular weight tropomyosins (TMs) is characteristic of transformed cells.
  • Tropomyosin 1 (TM1) has been previously identified as an anti-oncogene in ras-transformed murine fibroblasts.

Purpose of the Study:

  • To determine if TM1 acts as a ras-specific suppressor or a general suppressor of cellular transformation.
  • To investigate the role of TM1 in v-src transformed cells.

Main Methods:

  • V-src transformed fibroblasts with decreased TM1 expression were transduced to overexpress TM1.
  • Comparative analysis of control and TM1-overexpressing (src-T1) cells regarding growth rate, morphology, and anchorage-independent growth.

Main Results:

  • TM1-overexpressing cells exhibited reduced monolayer growth rates and a more spread, flat morphology.
  • Enhanced TM1 expression improved microfilament architecture.
  • Src-T1 cells demonstrated a complete failure to grow under anchorage-independent conditions.

Conclusions:

  • TM1 functions as a general anti-oncogene against functionally diverse oncogenes, including v-src.
  • TM1 is classified as a class II tumor suppressor protein.

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