PARP1 and glioblastoma: Consequently, GBM cell lines with genetically or pharmacologically inhibited RQC pathways were more susceptible to STS-induced apoptosis, evidenced by elevated executioner caspase 3/7 activity (Figure 5 – Figure Supplement 1A), enhanced PARP-1 cleavage (Figure 5 – Figure Supplement 1B, C), increased TUNEL staining (Figure 5H–K), and flow cytometry analysis (Figure 5 – Figure Supplement 1D–G).