FIGURE 4.

DAXX enhances tumorigenicity of PCa by specifically suppressing the autophagy machinery in vivo. A, ALVA-31 cells were stably transfected with control (C), DAXX, or DAXX and ULK1 (dK/D) shRNA (left), resulting in significant (∼93%) knockdown (right, protein levels). B, xenograft experiments were performed by injecting 10 million cells/mouse. There were six mice per group. Tumor kinetics (left) and wet weight (right) analyses demonstrate that when ULK1, an essential component of the autophagy machinery, is knocked down, tumor growth is restored in DAXX K/D cells. C, quantitative immunohistochemical analysis was performed using excised tumor tissue corresponding to CNTL (n = 6), DAXX K/D (n = 6), and DAXX/ULK1 dK/D (n = 6) tumors from ALVA-31 injections. Tissue sections were stained using an antibody specific for the autophagy marker LC3 (top row). A negative control (hematoxylin) was also included (bottom row). Immunostaining was quantified and analyzed using Aperio ImageScope software. Statistical significance was assessed by unpaired Student's t test. Representative ×40 images are shown. Error bars, S.E.