Figure 1

CPEB2 is downregulated in glioma tissues and inhibits cell proliferation and promotes apoptosis in U87 cells. GlioVis (a web application for exploring brain tumors expression datasets) and GENT2 database was used for expression analysis of CPEB2 in glioma patients. (A–D) Analysis of CPEB2 expression in glioma in Rembrandt dataset (Non-tumor n = 28, Oligodendroglioma n = 67, Astrocytoma n = 147, Unknown glioma n = 65) (A), Kamoun dataset (Non-tumor n = 9, Oligodendroglioma n = 114, Oligoastrocytoma n = 32) (B), Gill dataset (Non-tumor n = 17, GBM contrast-enhancing n = 38) (C), and Grzmill dataset (Non-tumor n = 2, Oligodendroglioma n = 6, Astrocytoma n = 8) (D). (E) Graph showing the change in expression of CPEB2 in a cohort of 156 glioblastoma patients versus non-tumor control (n = 5) in TCGA-GBM database. (F) Expression of CPEB2 across different subtypes of gliomas. Graph from GlioVis showing lower expression of CPEB2 in astrocytoma and oligodendroglioma as compared to glioblastoma in Rembrandt dataset (Oligodendroglioma n = 67, Astrocytoma n = 147, GBM n = 218). (G) Graph from GENT database showing lower expression of CPEB2 in grade II (n = 239) and grade III (n = 239) tumors as compared to grade IV (n = 451). (H,I) The efficiency of CPEB2 overexpression and knockdown in U87 cells. J Cell growth of U87 cells with CPEB2 overexpression or not was detected by CCK-8 assays after 1, 2, 3 and 4 days (n = 5). (K) Cell growth of U87 cells with CPEB2 knockdown or not was detected by CCK-8 assays after 1, 2, 3 and 4 days (n = 5). (L) Colony formation of U87 cells with CPEB2 overexpression or not. (M) Colony formation of U87 cells with CPEB2 knockdown or not. (N, O) Indicated U87 cells were stained with EDU and DAPI. The red color indicates EDU-positive nuclei. The statistical analysis of EDU staining was performed by Image-Pro Plus 6.0 software (n = 3). Column graph was mean ± SEM of three independent experiments. (P,Q) Western blot analysis of the expression levels of cleaved caspase 3 (C-caspaase 3). (R,S) Flow cytometry detection of apoptosis with Annexin V/PI staining. U87 cells with CPEB2 overexpression or knockdown were treated with 25 μg/ml cisplatin for 24 h. Apoptotic cells were detected and quantified with flow cytometry. All values are mean ± SEM. Two way ANOVA followed by Tukey's multiple comparison test or Student t-tests were used. *P < 0.05, **P < 0.01, and ***P < 0.001. SEM standard error of the mean.