Figure 4. MET is Essential for Growth, Sphere-forming Capacity, Motility, and Invasion of Wild-Type Prostate Stem Cells, and is Partially Regulated by SP1 Interacting with p53.

(A–G) qRT-PCR (A) and Western blot (B, C) of Met expression, prostasphere size (D), sphere-forming capacity (E), migration (F), and invasion (G) of CD49f^hi/Sca-1⁺ stem cells isolated from 3-month-old wild-type (WT) mice (n=3) and cultured under normoxic (20% O₂, A, B, D–G) and hypoxic (0.2% O₂, A–G) conditions. *P<0.05, **P<0.01, ***P<0.001. Error bars denote SD. Very similar results were obtained in separate experiments with two different Met siRNAs. (H, I) Co-immunoprecipitation of cell lysates with SP1 (H) or p53 (I) antibodies followed by Western blot with p53 or SP1 antibodies, respectively, in CD49f^hi/Sca-1⁺ stem cells isolated from 3-month-old WT mice (n=3; Upper panels, IP). Samples of the same lysates were used for Western blot with p53 or SP1 antibodies before precipitation (Lower panels, WB). (J) Effect of mithramycin A (100 nM) on MET expression of CD49f^hi/Sca-1⁺ stem cells isolated from 3-month-old WT, mir-34^PE−/−, p53^PE−/−, and p53^PE−/−mir-34^PE−/− mice (n=3).