Cytostatic and cytotoxic effects of tyrphostin AG1296 on RMS cells

Aim of the study: The aim of the work was to determine the influence of tyrphostin AG1296, an inhibitor of platelet-derived growth factor receptor (PDGFR) tyrosine kinase, on autocrine growth of rhabdomyosarcoma (RMS) cells.

Materials and methods: RMS cells were cultured in serum-free DMEM/F12 medium. Modified crystal violet (CV) and MTT methods were used to determine the RMS cells’ proliferation and viability. In­fluence of the investigated inhibitor on cell apoptosis or necrosis was determined by differential staining with Hoechst No. 33258 and propidium iodide.

Results: The AG1296 inhibitor affects RMS cell proliferation in a dose-dependent way at the concentration range 1–100 µM. At concentrations above 25 M there was 100% inhibition of growth of these cells and a cytotoxic effect was noticed. 50% inhibition of RMS cells proliferation (IC50) was observed at concentration 6.65 ±0.44 µM (determined by CV method) and 7.30 ±0.26 µM (determined by MTT method). The differential staining method shows that this inhibitor causes a cytotoxic effect.

Conclusion: The results of these experiments indicate that autocrine growth of RMS cells is regulated by at least one autocrine loop, involving platelet-derived growth factor (PDGF) and its receptor (PDGFR).

The fact that tyrphostin AG1296 is able to complete inhibition of RMS cell growth in vitro gives a chance for providing a new group of antitumor drugs, which may be more effective than the medicines used so far.