MSC effect on tumor growth and HIF-2α expression in 786–0 ccRCC xenografts. (A) Inhibition of ccRCC tumor growth by MSC in xenografts. HIF-2α expressing 786–0 cells (10 million) were transplanted into nude mice for establishing the xenografts. Small pieces (~50 mg) of tumor tissues were transplanted subcutaneously into nude mice and treatment began when tumor weighed 200–250 mg. Mice were randomized and divided into two groups, each containing 5 mice. One group was treated with saline and the other group was treated with MSC (0.2 mg/mouse/day; the optimal nontoxic dose) daily for 18 days. Tumor volume was measured daily. (B) HIF-2α is inhibited by the therapeutic dose of MSC in 786–0 xenografts. Tumor xenografts collected after 18 days of the MSC treatments and processed to extract protein and HIF-2α levels were assessed by western blot. β-actin expression was used as a loading control.