Figure 2. VRK1 dependency is correlated with VRK2 expression.

(A) Whole-genome Pearson correlations between gene expression from CCLE (21Q3) and VRK1 dependency in the DepMap database (21Q3) and adjusted P values. (B) Scatterplot showing VRK1 dependency versus VRK2 expression. Extent of VRK2 promoter methylation is indicated by dot size. Red dots represent cell lines of CNS lineage, and blue dots represent PNS lineage. (C) VRK2 promoter methylation status stratified by clinical characteristics across the TCGA GBM-LGG cohort. LGG, low grade glioma; GBM, glioblastoma multiforme. Violin plots with mean (solid line) and first and third quartiles (dashed line). (D) VRK2 promoter methylation in pediatric high-grade gliomas and DMGs with wild-type histone H3 and mutant histone H3 (K27M or G34R). Data from Mackay et al., 2017 (39). Violin plots with mean (solid line) and first and third quartiles (dashed line). (E) Cell viability following 14 days’ KO of VRK1 in VRK2^lo LNZ308 and LN443 cell lines and VRK2^hi GAMG and SF172 cell lines. (F) Cell viability analysis 14 days following VRK1 KO in VRK2^hi GBM cell line (SF172), expressing control CRISPR sgRNA or sgRNA targeting VRK2. (n = 3; mean ± SD.) (G) Immunoblot showing the overexpression of exogenous VRK2^WT, VRK1^WT, and kinase-inactive VRK1^K179E in NB-1 NB cells with or without VRK1 KO. RFP, red fluorescent protein. (H) Cell viability analysis for NB-1 cells in G following 14 days of VRK1 KO in cells overexpressing VRK2^WT, VRK1^WT, and kinase-inactive VRK1^K179E. (n = 3; mean ± SD.) (I) Effect of VRK2^WT or VRK2^K168E overexpression on LN443 GBM cell viability following 14 days VRK1 KO. (n = 3; mean ± SD.) *P < 0.05, **P < 0.001, ***P < 0.0001; significance was determined by 2-tailed Student’s t test (E) and 1-way ANOVA with Tukey’s test (C, D, F, H, and I).