RG13022 (Tyrphostin RG13022) is a tyrosine kinase inhibitor; inhibits the autophosphorylation reaction of the EGF receptor (IC50: 4 μM).

RG13022 suppresses EGF-stimulated cancer cell proliferation. In a cell-free reaction, RG13022 inhibits the autophosphorylation reaction of the EGF receptor in immunoprecipitates (IC50: 4 μM). RG13022 inhibits colony formation (IC50: 1 μM) and DNA synthesis (IC50: 3 μM) by HER 14 cells (stimulated by 50 ng/mL EGF), in a dose-dependent manner. RG-13022 inhibits not only EGF-induced growth but also growth stimulated by insulin, insulin-like growth factor I, insulin-like growth factor II, or transforming growth factor alpha. RG-13022 also totally blocks estrogen-stimulated phosphorylation of the EGF receptor, as well as estrogen-induced cell proliferation, suggesting that functioning TK pathways are required for estrogen action.

RG13022 suppresses tumor growth in nude mice. It also increases the lifespan of these tumor-bearing nude mice.

40 mM stock solutions of RG13022 is made in 100% DMSO and diluted with the culture medium before addition to the cells. MH-85 cells and HER 14 cells are plated in culture medium in the presence or absence of increasing concentrations of RG-13022 or RG-14620 for 10 days. At the end of culture, the cells are fixed with 4% (v/v) formaldehyde and stained with hematoxylin. Numbers of colonies including more than 20 cells in each well are counted under the microscope[1].