Deletion of Hk2 caused specific changes in pathology and pathway activation in hGFAP-cre;SmoM2-driven medulloblastoma. (A) Comparison of cerebella at P15 from wildtype (wt; left column), hGFAP-cre;SmoM2;Hk2fl/+ (middle column) and hGFAP-cre;SmoM2;Hk2fl/fl (right column) mice. Proliferating cells were visualized by IHC for PCNA (top row) and differentiated neurons were labeled by IHC for NeuN (bottom row). Antibodies are visualized in brown, and nuclei are counterstained blue with hematoxylin. At least 3 tumors of each genotype were examined and representative images are presented. (B) IHC for endothelial marker CD31 (red) demonstrates increased capillary density in Hk2-deficient medulloblastoma. Nuclei are counterstained with DAPI. (C) Comparison of proliferation and early differentiation using IHC for PCNA (green) and p27 (red) respectively, in hGFAP-cre;SmoM2;Hk2fl/+ (top row) or hGFAP-cre;SmoM2;Hk2fl/fl (bottom row) medulloblastoma. H & E-stained sections are provided for reference (left column). Yellow arrowheads highlight blood vessels. Proliferating tumor cells in Hk2fl/fl medulloblastoma concentrated around blood vessels, in contrast to the even distribution of proliferating cells in Hk2fl/+ tumors. In Hk2fl/fl medulloblastoma, tumor cells that were further from the perivascular region were PCNA– and p27+, indicating cell cycle exit. (D) Western blot demonstrates increased phosphorylation of AMP-activated kinase (AMPk) and Acyl-CoA Carboxylase (Acc1) in Hk2fl/fl medulloblastoma, along with reduced expression of proliferation marker Cyclin D2. Decreased abundance of cC3 in Hk2fl/fl medulloblastoma demonstrates that loss of Hk2 did not induce apoptosis. Scale bars = 1,000 μm (A), 100 μm (B) and 50 μm (C).