Fig. 5.

PRMT5 regulates ATF4 and downstream oxidative stress response. a) PRMT5 inhibition attenuates stressor-induced ATF4 levels. OCI-AML-20 and UCSD-AML-1 cells were pretreated with LLY-283 (100 nM) and exposed to ER stressors (8 h): the endoplasmic reticulum stressors tunicamycin (glycosylation inhibitor), thapsigargin (Ca²⁺ pump inhibitor), proteasome inhibitor bortezomib, glutamine starvation, or oxidative stress-inducing arsenic (As) trioxide. b) PRMT5 inhibition leads to higher ROS levels. Flow cytometry histograms for oxidative stress indicator DCFDA fluorescence in UCSD-AML-1 cells treated with 100 nM of LLY283 for four days. c) Quantitation of oxidative stress upon PRMT5 inhibition as in b) in UCSD-AML-1, OCI-AML-20, and K562 cells. N = 4, means ± SD, *p < 0.05. d) GSH content is decreased upon PRMT5 inhibition (LLY283, 100 nM, 4 days) in UCSD-AML-1 cells. Absolute and GSSH normalized GSH levels are shown. N = 3, means ± SD * p < 0.05. e) N-acetyl cysteine (NAC) antioxidant partially rescues PRMT5 inhibition-induced cell proliferation block in UCSD-AML-1. Cells were treated with LLY283 and (0.5 mM) NAC for four days. Cell viability was determined using resazurin assay N = 3, means ± SEM shown. f) PRMT5 inhibition (LLY238 30 nM 3 days) sensitizes UCSD-AML-1 cells to tert-butyl hydroperoxide (TBHP) exposure for 24 h. Cell viability was determined using resazurin assay, N = 3, means ± SD, *p < 0.05.