MCF-7 breast cancer xenograft model

South Texas Accelerated Research Therapeutics (START; San Antonio, Texas) evaluated the antitumor activity of G1T38 in a START Cell-Based Xenograft (START-CBX) tumor model, MCF-7, representing human breast cancer. Data collected from this efficacy study included animal weights, observations, and tumor dimensions. This information was used to determine agent tolerability based on weight change and gross physiologic changes, and anticancer activity based on tumor growth inhibition or regression. Study endpoint was Day 60. MCF-7 cells were harvested from culture and injected into immune-deficient mice and the study initiated at a mean tumor volume of approximately 150-250 mm³. In all studies, G1T38 and palbociclib was given as a daily oral treatment at 10, 25, 50 or 100 mg/kg. Tamoxifen was administered subcutaneous (s.c.) at 20 mg/kg M-F, fulvestrant was administered s.c. 5 mg per mouse once a week, GW5638 was administered orally at 25 mg/kg daily and GDC0941 (Selleckchem) was administered orally at 100 mg/kg daily for the duration of each study. Tumor growth inhibition (%TGI) was calculated using the following equation: %TGI=(1-(((TV_tmtfinal-TV_tmtinitial))/((AVERAGE(TV_ctlfinal))-(AVERAGE(TV_ctlinital)))))*100. All protocols were IACUC approved and experiments were completed at START.