MGMT and glioblastoma: In order to prove the role of mTOR signaling and the resulting expression of pro-tumorigenic genes as a chemoresistance mechanism of surviving MGMT promoter-methylated GBM cells, co-cultured GBM cells (PCa) were treated with the mTOR inhibitor Torin2 in the presence or absence of TMZ+AT101/AT101 for 6 days (Figure 5).