Redistribution of EZH2 promotes malignant phenotypes by rewiring developmental programs (2019)
Figure 4

Figure 4: Aberrant silencing of EMX2 and de-repression of HOX genes in glioma patients

A. Expression of EMX2 in normal brain and GBM patient samples. Data sourced from the Repository of Molecular Brain Neoplasia Data (REMBRANDT). Four asterisks indicate p-value < 0.0001 (two-tailed Mann Whitney U test). Bars represent median ± interquartile range. Values are expressed relative to the mean of normal brain samples. N: 21 for normal brain, 214 for GBM. Note that the extent of EMX2 repression in GBM patients is likely underestimated due to the possible presence of normal adjacent tissue in the analysed samples, and due to the intrinsic background noise of microarrays, which limits detection of truly silenced genes.

B. Relative expression of HOX genes in normal brain and GBM patient samples as detected by microarray analysis. Data sourced from REMBRANDT. Values are expressed relative to the median of normal brain samples. In the boxplots, the top, middle and bottom box delimiters represent the 75th, 50th and 25th percentiles of the data, respectively. Top and bottom whiskers show the 75th percentile + 1.5*interquartile range and 25th percentile - 1.5*interquartile range, respectively. One asterisk indicates p-value <0.05 (two-tailed Mann Whitney U test corrected for multiple comparison using Holm's method). N: 21 for normal brain, 214 for GBM. Data was not available for HOXD8.

C. Covariance between EMX2 and EZH2 expression levels in GBM patient samples, as detected by microarray analysis. Data sourced from REMBRANDT. P-value and correlation coefficient (r) of the covariance are shown (Spearman rank correlation). Every dot is a patient. N: 214.

D. Expression levels of EMX2 (top) and EZH2 (bottom) in tumour or adjacent normal regions laser microdissected from human GBM tumours as detected by RNA-seq. Data sourced from the Ivy Glioblastoma Atlas. FPKM: fragments per kilobase of transcript per million. The significance of the differential expression in normal and tumour regions across patients is indicated (two-way ANOVA). Bars represent mean ± SEM. N: 3 regions sampled for each GBM tumour, 2, 3, 2, 3, 2, 3, 3 and 1 regions for normal tissue of patients 1-8, respectively.

E. Scoring of EMX2 and EZH2 mRNA staining intensity in human GBM tumour samples. Scoring system: - 0-0.5 foci/nuclei, + 0.51-0.75 foci/nuclei, ++ 0.76-1 foci/nuclei and +++ >1 foci/nuclei (see Methods).

F. Hematoxylin and eosin (H&E) staining of a human GBM tumour. The black square represents the approximate location of the field shown in G (left image). Serial sections were used for H&E and RNA-FISH. Scale bar: 300 µm.

G. Visualisation of EZH2 (green) and EMX2 mRNA (red) in a human GBM tumour by RNA FISH. Nuclei were counterstained with DAPI. Scale bar: 20 µm.

H. Expression of EMX2 (left) and EZH2 (right) in glioma patient samples, grouped according to tumour grade, as detected by RNA-seq. Data sourced from the Chinese Glioma Genome Atlas. Four asterisks indicate p-value < 0.0001 (Kruskal-Wallis test). Bars represent median ± interquartile range. N: 109 for grade II -, 72 for grade III, 144 for grade IV. RPKM: Reads per kilobase of transcript per million.