Vulnerability of invasive glioblastoma cells to lysosomal membrane destabilisation (2019)
Figure 1

Figure 1.

Association of MDGI protein expression with patient survival and regulation of MDGI expression by hypoxia.

A. Glioma tumour micro arrays (grade II-IV gliomas) were stained to visualise MDGI (red). Samples from the epileptic brain served as a negative control. Scale bar 100 µm.

B. Overall survival of grade II and III glioma patients (n = 76) was significantly better when none/low MDGI (blue line) was detected compared to patients with moderate/high MDGI (red line) expression (P = 0.007). The cumulative survival rates were estimated by using the Kaplan-Meier method.

C. Analysis of the association of MDGI mRNA expression with glioma patient survival using the GlioVis data portal. In the TCGA GBMLGG dataset (n = 667), patients with low MDGI expression (green line; n = 333, events = 101, median = 67,5) show significantly better survival than patients with high MDGI (red line; n = 334, events = 138, median = 41.5) expression (P = 2e-04). HR = 0.62 (0.48 - 0.8). The cumulative survival rates were estimated by using the Kaplan-Meier method.

D. In glioblastoma samples, highest MDGI expression was observed in the mesenchymal subtype (M) compared to the classical (Cl) or pro-neural (PN) ones. However, it did not reach the statistical significance. GlioVis data portal, TCGA GBM dataset, n = 156. Pairwise t-test with corrections for multiple testing, p-values with Bonferroni correction.

E. MDGI expression was high in the leading edge of the tumour (LE) and in infiltrating tumour cells (IT) in the IVY_Gap dataset (n = 122) where the gene expression profile in different anatomical structures of glioblastomas was analysed. LE, leading edge; IT, infiltrating tumour cells; CT, cellular tumour (cells within the tumour mass); PC, pseudopalisading cells; MP, microvascular proliferation. Numbers in the graph depict the P values: Pairwise t-test with corrections for multiple testing, p-values with Bonferroni correction.

F. Western blot analysis shows MDGI expression in human glioma cells including patient-derived spheroids (S24, ZH161, ZH305, BT3, BT11, BT12, BT13), patient-derived adherent cells (BT5 and BT5R), and long-term cell lines (U87MG, LN229, LN308). Numbers above the lanes show the relative expression of MDGI compared to the levels of β-tubulin that served as loading control in each cell line. Representative Western blot image of 3 separate experiments is shown.

G. High MDGI and HIF-1α expression in the patient-derived glioblastoma spheroids decreased significantly when cells were cultured in medium containing 10 % of serum (FBS) for seven days. Numbers show the relative expression of MDGI and HIF-1α compared to the levels of β-tubulin. Expression in the serum-free medium was set as 1. Representative Western blot image of 2 separate experiments is shown.

H. MDGI expression in adherent glioma cell lines and in glioma cell spheroids after 24h culture under hypoxia (1 % O2) or normoxia (21 % O2). Numbers show the relative MDGI expression compared to the levels of β-tubulin. Expression under normoxia was set as 1. Representative Western blot image of 3 separate experiments is shown.