Fig. 6: Effect of MS-275 on glioma initiating cells and the role of RAD18 in glioma patients.

A Downregulation of RAD18 protein expression upon MS-275 exposure. Glioma initiating cells #1095 and #1095_IR were exposed to indicated drugs for 72 h. ß-ACTIN served as a loading control. B HDACi prevents the proliferation of glioma initiating cells. Micrographs of #1095 and #1095_IR cells after 13 and 24 days of indicated drug exposure (magnification, x40, scale bar, 100 µm). C Quantification of #1095 and #1095_IR spheroid size 13 days after treatment. D Quantification of #1095 and #1095_IR spheroid size 24 days after treatment. E MS-275 impairs the self-renewal potential of glioma initiating cells. Comparison of self-renewal potential in #1095 and #1095_IR upon indicated drug exposure by ELDA. The average stem cell frequency of both cell lines under indicated treatments result from three independent experiments and are shown. F RAD18 mRNA expression in glioma grade I, II, III, IV. Log2 fold-changes in expression are represented as box and dot-plots of each subtype and the indicated significances *P ≤ 0.05; **P ≤ 0.01 and ***P ≤ 0.001 result from t-test. G RAD18 mRNA expression correlates with survival of glioblastoma patients. Kaplan–Meier plot comparing the survival of GBM patients suffering from high RAD18-expressing glioblastomas (n = 15) and low RAD18-expressing glioblastomas (n = 17). Indicated significance result from log-rank test. For A, B, C, and D cells were exposed to MS-275 (1.5 µM), TMZ (50 µM) and TMZ/MS-275. Inf = infinity. P ≤ 0.001 and ****P ≤ 0.0001. Indicated significances result from an unpaired t-test.