Activation of smooth muscle α-actin promoter in ras-transformed cells by treatments with antimitotic agents: Correlation with stimulation of SRF:SRE mediated gene transcription

C. C. Kumar, Jae-Hong Kim, P. Bushel, L. Armstrong, J. J. Catino

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Smooth muscle α-actin promoter is repressed in ras-transformed fibroblast cells and derepressed in revertant cells. We have recently shown that serum response factor (SRF) which can bind to the serum response elements (SREs) present in the α-actin promoter, can activate α-actin promoter activity in ras-transformed cells and suppress transformation by ras. Agents that stimulate SRF expression and α-actin promoter activity in ras-transformed cells are expected to be potential candidates as antitumor agents. In this study, we show that treatment of ras-transformed cells with antitumor agents such as taxol, vincristine, vinblastine, colchicine, and nocodazole leads to 5- to 7-fold activation of α-actin promoter driven CAT activity, whereas there was very little effect on thymidine kinase promoter driven CAT activity. This activation occurred at subcytotoxic concentrations of these agents and correlated with inhibition of cell cycle progression. Furthermore, these agents stimulated SRF expression in ras-transformed cells, as measured by its SRE binding activity. The increase in α-actin expression is accompanied by the restoration of actin filaments into organized bundles. These results suggest a novel mechanism by which antimitotic agents suppress the ras-transformed phenotype.

Original languageEnglish
Pages (from-to)1285-1292
Number of pages8
JournalJournal of Biochemistry
Volume118
Issue number6
Publication statusPublished - 1995 Dec 1
Externally publishedYes

Keywords

  • α-actin promoter
  • Activation
  • Antimitotic agents
  • SRE
  • SRF

ASJC Scopus subject areas

  • Biochemistry
  • Statistics, Probability and Uncertainty
  • Applied Mathematics
  • Physiology (medical)
  • Radiology Nuclear Medicine and imaging
  • Molecular Biology

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