RG 13022

RG-13022 inhibits autophosphorylation of the EGF-receptor in HER 14 cells after an overnight incubation.The IC50 of RG-13022 is 5 μM. RG-13022 inhibits colony formation and DNA synthesis by HER 14 cells, which are stimulated by 50 ng/mL EGF, in a dose-dependent manner. The IC50 for RG-13022 is 1 μM for HER 14 colony formation and 3 μM for HER 14 DNA synthesis. RG-13022 also suppresses colony formation and DNA synthesis by EGF-stimulated MH-85 cells in a dose-dependent manner. The IC50 for RG-13022 on MH-85 cells is 7 μM for colony formation and 1.5 μM for DNA synthesis.^[1].

MH-85 cells (100/well; 24-well plate) and HER 14 cells (200/dish; 10-cm dish) are plated in complete medium, either alpha MEM or DMEM, respectively, supplemented with 10% FCS. After overnight culture, the culture medium is switched to alpha MEM supplemented with 0.2% PCS and 50 ng/mL EGF (MH-85) or DMEM supplemented with 0.5% PCS and 50 ng/mL EGF (HER14). The cells are cultured in this medium in the presence or absence of increasing concentrations of RG-13022 for 10 days. At the end of culture, the cells are fixed with 4% (v/v) formaldehyde in calcium-magnesium-free phosphate-buffered saline for 15 min at room temperature and stained with hematoxylin. Numbers of colonies including more than 20 cells in each well are counted under the microscope.

RG-13022 (400 μg/mouse/day) significantly inhibits MH-85 tumor growth. Because of slower tumor growth, MH-85 tumor-bearing animals receiving injections of RG-13022 show less cachexia and hypercalcemia, eat more food, and are more active than untreated MH-85 tumor-bearing animals. As a result of suppression of tumor growth, RG-13022 prolongs the life span of MH-85 tumor-bearing animals. Administration of mAb108 i.p. (1 mg/mouse/day) at 1, 5, and 10 days after MH-85 inoculation of RG-13022 (400 μg/mouse/day) for 14 days profoundly inhibits MH-85 growth in nude mice.^[1].