Related Experiment Videos
[Inhibition of RAS-transformation by SCH51344]
1Dept. of Tumor Biology, Schering Research Institute.
Abstract:
RAS controls at least two signaling pathways, one regulating extracellular signal-regulated kinase (ERK) activation and the other controlling membrane ruffling formation. Activating RAS mutations are commonly found in human tumors, making RAS and its downstream signaling pathways important targets for tumor therapeutics. We have developed a reporter-gene based assay system, utilizing transformation sensitive alpha-actin promoter, to identify compounds that inhibit the transforming activity of RAS either directly or indirectly. SCH51344 is a pyrazolo-quinoline derivative, identified based on its ability to depreprses alpha-actin promoter in RAS-transformed cells and shown to be a potent inhibitor of RAS-transformation. However, this compound had very little effect on the activities of the proteins in the ERK pathway, suggesting that it inhibits RAS-transformation by a novel mechanism and acts on a signaling pathway distinct from ERK pathway. Recently, in collaboration with Dr. Dafna Bar-Sagi's group, we have shown that SCH51344 inhibits 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. Our results indicate that SCH51344 inhibits a critical component of the membrane ruffling pathway downstream from RAC and suggest that targeting the membrane ruffling pathway may be an effective approach to inhibit transformation by RAS.
Insights
RAS mutations drive tumor growth. Researchers identified SCH51344, a compound that inhibits RAS-driven cell transformation by targeting membrane ruffling, a pathway distinct from ERK signaling.
Area of Science:
- Oncology
- Molecular Biology
- Cell Signaling
Context:
- Activating RAS mutations are prevalent in human cancers, making RAS signaling a key therapeutic target.
- RAS influences cell behavior through pathways like ERK activation and membrane ruffling.
- Developing novel inhibitors for RAS-driven transformation is crucial for cancer treatment.
Purpose:
- To identify compounds that inhibit RAS-mediated cell transformation.
- To elucidate the mechanism of action for novel RAS inhibitors.
- To explore the role of membrane ruffling in RAS-driven oncogenesis.
Summary:
- A reporter-gene assay identified SCH51344, a pyrazolo-quinoline derivative, as a potent inhibitor of RAS-transformation.
- SCH51344 selectively inhibits RAS-induced membrane ruffling without affecting ERK or Jun kinase pathways.
- The compound acts downstream of RAC, targeting a novel component of the membrane ruffling pathway.
Impact:
- SCH51344 represents a potential therapeutic agent targeting a distinct RAS signaling pathway.
- Inhibiting the membrane ruffling pathway offers a new strategy for combating RAS-driven cancers.
- This research provides insights into the complex mechanisms of RAS-mediated cell transformation.