Caffeine Sensitizes U87-MG Human Glioblastoma Cells to Temozolomide through Mitotic Catastrophe by Impeding G2 Arrest

Figure 7

Proposed mechanisms for caffeine in sensitizing TMZ’s efficacy. TMZ causes DNA damage, activates ATM/p53/p21 pathway, and induces significant G2 arrest (full line). Caffeine inhibits the phosphorylation of ATM and thus suppresses the activation of DDR pathway. G2 delay is abrogated, cells with damaged DNA enter mitotic phase prematurely, and augmented MC occurs (dotted line). Our results did not show a dependent association between MC and apoptosis; hence further studies are warranted.