(A) Tumor mass from s.c. implantation of T4121 GSCs cultured under different methionine restriction conditions (100%, 115.5 μM; 10%, 11.5 μM; 5%, 5.75 μM) for 3 days before injection. (B) Kaplan-Meier curve of mice bearing intracranial xenograft of T3136 GSCs cultured for 3 days under different methionine restriction conditions (100%, 115.5 μM; 10%, 11.5 μM; 5%, 5.75 μM) before injection. (C) Tumor mass from s.c. implantation of T4121 GSCs transduced with shCTRL, shNNMT.840, or shNNMT.330 lentivirus. Scale bars: 10 mm. (D and E) H&E staining of tumor-bearing brains and survival of tumor-bearing mice bearing intracranially xenografted T4121 GSCs transduced with shCTRL, shNNMT.840, or shNNMT.330 lentivirus. Cohorts of 12 mice were implanted with tumors from 2 mice in each experimental arm that were randomly selected for sacrifice for H&E staining 2 weeks after implantation, and 10 were used to observe mice survival rate. The P value represents the Mantel-Cox log-rank test of survival analysis.