Figure 1  YAP promotes medulloblastoma cell tumorigenicity, proliferation and survival
(A) Tumor-free survival curve. Two hundred thousand NeuroD2-SmoA1 tumor cells transduced with either GFP or YAP were implanted into the brain of NOD/SCID post-natal day 2 pups. Animals were sacrificed when they developed symptoms. YAP-over-expressing medulloblastomas occurred with a higher penetrance and earlier development compared to GFP-transduced tumors (Long-rank Test, p=0.0047). 14/17 animals implanted with YAP-SmoA1 medulloblastomas cells developed tumors while only 8/17 animals implanted with GFP-SmoA1 cells did. A similar trend was observed when nonimmunocompromised recipient pups were used (Long-rank Test, p=0.0487; Supplementary Figure 1).
(B) Representative western blot analysis of GFP-SmoA1 and YAP-SmoA1 medulloblastomas. Note reduced cleaved caspase 3, increased cyclin D2, and increased VEGF in YAP-SmoA1 medulloblastoma.
(C) Immunohistochemical analysis of YAP, the endothelial cell marker CD31, cleaved caspase 3, and phosphorylated histone H3 in GFP-SmoA1 (top) and YAP-SmoA1 (bottom) medulloblastomas. YAP-SmoA1 tumors have significantly reduced apoptosis and increased proliferation compared with GFP-SmoA1 tumors, indicated in the graphs.
(D) Immunohistochemical analysis and quantification of apoptosis (cleaved caspase 3) and proliferation (phosphorylated histone H3) in GFP-SmoA1 and YAP-SmoA1 medulloblastomas three hours after tumor-bearing animals were irradiated (2 Gy). Statistically significant differences are indicated as (*) P < 0.05; (***) P < 0.001.