Human breast tumor xenograft mouse model

The experimental protocol was established according to institutional ethical guidelines for Animal Research and Care and approved by the Ethics Committee of the Second Affiliated Hospital of Nanjing Medical Universi [⁴²]. Six-week-old female BALB/c nude mice (National Rodent Laboratory Animal Resources, Shanghai, China) weighing approximately 22 g were randomly divided into three groups of six each. MDA-MB-231 cells were s.c. injected into the mice (8 × 10⁶ per mouse). After the tumors grew to approximately 100 mm³, the mice were injected intraperitoneally with either vehicle or WithaD (5 mg/kg or 2.5 mg/kg) every day for 18 days. The tumor size was measured with a caliper (calculated volume = shortest diameter² × longest diameter/2) at three-day intervals.