Fig. 4. USP15 expression correlates with disrupted redox signaling in AML.

A Normalized enrichment scores for the top 15 upregulated (red, top) and downregulated (blue, bottom), significantly altered gene sets in USP15^hi versus USP15^low AML patient samples from the BEAT-AML dataset. P-value < 0.05. B Selected gene set enrichment plots for USP15^hi and USP15^low AML groups. Shown is the enrichment of NPM1-mutated AML genes in USP15^hi AML and enrichment of hypoxia-related genes in USP15^low AML, (P < 0.00001). NES normalized enrichment score. C Schematic overview of the USP15-KEAP1-NRF2 pathway as it pertains to observations in USP15^high and USP15^low AML. Elevated USP15 is required to maintain redox homeostasis by directly sustaining KEAP1 protein expression and as a result inhibition of NRF2. In the absence of USP15, KEAP1 expression is diminished resulting in NRF2-mediated redox stress. D Immunoblot of USP15, KEAP1, NRF2, and GAPDH in normal CD34+ cells and a panel of AML cell lines. Representative data from 2 replicate experiments. E An X, Y coordinate dot plot using the quantities of USP15 and KEAP1 determined by mean gray area value in ImageJ, normalized to GAPDH for each sample from panel (D). Linear regression was performed to calculate the R-squared and P-values. The best-fit line is shown.