Figure 4. Cancer cells with downregulated OLA1 are more resistant to multiple stresses.

(A) Cytotoxicity analysis of the MDA-MB-231 shCTL and shOLA1 cells exposed to different doses of H₂O₂ for 5 h. The OLA1 KD was verified by IB. (B) MDA-MB-231 shOLA1 cells were transfected with FLAG-only or FLAG-resOLA1 plasmid for 48 h then treated with H₂O₂ for 5 h. The re-expression of OLA1 was confirmed by IB. (C) MDA-MB-231 shCTL and shOLA1 cells were pretreated with 20 μM BTdCPU (N,N’-diarylurea) and 20 μM Salubrinal for 16 h then exposed to H₂O₂ for another 6 h. The status of eIF2α-P at the end of pretreatment was examined by IB. (D) Cytotoxicity analysis of the MDA-MB-231 shCTL and shOLA1cells exposed to different doses of TM for 5 h. Error bars: SD, Student’s t test: *p < 0.05; **p < 0.01; NS, not significant.