Related Experiment Video
Updated: Jun 2, 2026
Methods for Evaluating the Role of c-Fos and Dusp1 in Oncogene Dependence
Published on: January 7, 2019
Enzyme, whole cell and invivo tumor-models to identify and assess inhibitors of pp60(c-SRC)
1BRISTOL MYERS SQUIBB CO,DEPT EXPTL THERAPEUT,WALLINGFORD,CT 06492.
Abstract:
Many oncogenes encode tyrosine kinases and the identification of appropriate inhibitors is an appealing proposition for the development of selective anticancer agents. These studies outline some screening models which we are currently developing in which we have evaluated a variety of compounds, reported to have tyrosine kinase inhibitory activity, as antitumor agents. In an enzyme based assay, using isolated pp60c-src, a variety of indolocabazoles, flavonoids, tyrophostins, herbimycin A and natural product cytotoxic agents were tested. Genistein, quercetin, staurosporine and herbimycin A were selected for comparison in whole cell studies. Soft agar colony formation of an activated c-src transformed NIH3T3 line was inhibited (IC50) by genistein (4.5 mug/ml) and quercetin (6.5 mug/ml) at similar concentrations and by herbimycin A (7 ng/ml) and staurosporine (1.3 ng/ml) at much lower concentrations. However, these agents inhibited colony formation of v-raf, H-ras and polyoma transformed NIH3T3 lines at comparable concentrations suggesting no selective inhibition of the src mediated transformation was being produced. Furthermore, quercetin failed to inhibit tyrosine phosphorylation of cellular proteins at concentrations shown to inhibit colony formation. Nevertheless. daily quercetin treatment (ip) for seven days at 1000 and 500 mg/kg/day did produce a meaningful increase in median survival time of athymic mice inoculated ip with 106 c-src transformed NIH3T3 cells. The screening models described are now being used to identify and develop new tyrosine kinase inhibitors from natural products and assess their potential as antitumor agents.
Insights
Researchers developed screening models to find tyrosine kinase inhibitors for cancer treatment. While some compounds inhibited cancer cell growth, selectivity for src-mediated transformation was not observed. Quercetin showed survival benefits in mice, highlighting potential for natural product drug development.
Area of Science:
- Oncology
- Biochemistry
- Pharmacology
Background:
- Tyrosine kinases are key targets for anticancer drug development.
- Identifying selective tyrosine kinase inhibitors is crucial for effective cancer therapy.
Purpose of the Study:
- To develop and utilize screening models for evaluating tyrosine kinase inhibitors as antitumor agents.
- To assess the efficacy and selectivity of various compounds, including natural products, against cancer cells.
Main Methods:
- Enzyme-based assays using isolated pp60c-src.
- Whole-cell studies assessing soft agar colony formation in transformed NIH3T3 cell lines.
- In vivo studies evaluating compound efficacy in athymic mice.
Main Results:
- Genistein, quercetin, herbimycin A, and staurosporine inhibited colony formation in src-transformed cells.
- Compounds showed similar inhibition across v-raf, H-ras, and polyoma-transformed cells, indicating a lack of src-specific inhibition.
- Quercetin treatment increased median survival time in mice with c-src-transformed tumors.
Conclusions:
- The developed screening models can identify potential tyrosine kinase inhibitors.
- Quercetin demonstrates antitumor potential in vivo, warranting further investigation.
- Natural products are a promising source for novel anticancer agents targeting tyrosine kinases.
