SCH 51334, an inhibitor of RAS/RAC-mediated cell morphology pathway

C. Chandra Kumar, Kazumasa Ohashi, Kyoko Nagata, Amy Walsh, Dafna Bar-Sagi, Kensaku Mizuno

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


RAS interacts with multiple targets in the cell and controls at least two signaling pathways, one regulating extracellular signal-regulated kinase (ERK) activation and the other controlling membrane ruffling formation. These two pathways appear to act synergistically to cause transformation. Human smooth muscle α-actin promoter is repressed in RAS-transformed cells and derepressed in revertant cell lines, suggesting that it is a sensitive marker to follow phenotypic changes in fibroblast cells. SCH 51344 is a pyrazoloquinoline derivative identified on the basis of its ability to derepress α-actin promoter in RAS-transformed cells. Previous studies have shown that SCH 51344 is a potent inhibitor of RAS transformation. However, SCH 51344 had very little effect on the activities of proteins in the ERK pathway, suggesting that it inhibits RAS transformation by a novel mechanism. Recently, we have demonstrated that SCH 51344 specifically blocks membrane ruffling induced by activated forms of H-RAS, K-RAS, N-RAS, and RAC. Treatment of fibroblast cells with this compound had very little effect on RAS-mediated activation of ERK and JUN kinase activities. SCH 51344 was effective in inhibiting the anchorage-independent growth of Rat-2 fibroblast cells transformed by the three forms of oncogenic RAS and RAC V12. These results indicate that SCH 51344 inhibits a critical component of the membrane ruffling pathway downstream from RAC and suggest that targeting this pathway may be an effective approach to inhibiting transformation by RAS and other oncogenes.

Original languageEnglish
Pages (from-to)122-131
Number of pages10
JournalAnnals of the New York Academy of Sciences
Publication statusPublished - 1999 Jan 1
Externally publishedYes

ASJC Scopus subject areas

  • Neuroscience(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • History and Philosophy of Science


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