Fig. 8: Inhibition of pathogenic JAK-STAT signaling by tamoxifen is rescued by complex II activation or ATP supplementation. | Nature Communications

Fig. 8: Inhibition of pathogenic JAK-STAT signaling by tamoxifen is rescued by complex II activation or ATP supplementation.

From: Tamoxifen for the treatment of myeloproliferative neoplasms: A Phase II clinical trial and exploratory analysis

Fig. 8: Inhibition of pathogenic JAK-STAT signaling by tamoxifen is rescued by complex II activation or ATP supplementation.The alternative text for this image may have been generated using AI.

a-b Frequency of pSTAT5+ HEL cells or SET-2 cells (a) and representative flow cytometry histograms of pSTAT5 expression (b) at baseline or after thrombopoietin (THPO) stimulation (blue), in combination with 4OH-TAM (red) or vehicle (n = 3 independent experiments). Combined treatment with the mitochondrial complex II substrate monomethyl succinate (MMS, green) rescues the reduction of pSTAT5 by 4OH-TAM. C, control. c-d Frequency of pSTAT5+ THPO-stimulated HEL cells (c) and representative flow cytometry histograms of pSTAT5 expression (d) in HEL cells treated with 4OH-TAM alone (red) or vehicle (blue), or in combination with cell-permeable ATP (5 mM 8-Br-ATP, yellow) (n = 3 independent experiments). ATP supplementation rescues the reduction of pSTAT5 by 4OH-TAM. a,c Data are mean + SEM; *p < 0.05, **p < 0.01, ***p < 0.001, One-way ANOVA and Tukey’s test. e Quantification (top) and representative Western blots (bottom) of STAT5 and phosphorylated (p) STAT5 level at baseline or after thrombopoietin (THPO) stimulation, in combination with 4 h vehicle/4OH-TAM treatment and mitochondrial complex II substrate monomethyl succinate (10 mM MMS) in HEL cell lines. Combined treatment with the mitochondrial complex II substrate monomethyl succinate (MMS) rescues the reduction of THPO-induced pSTAT5 by 4OH-TAM (n = 3 independent experiments). f-g Quantification (top) and representative Western blots (bottom) of JAK2 and phosphorylated (p) JAK2 (f, Tyr221; g, Tyr1007/8) level at baseline or after thrombopoietin (THPO) stimulation, in combination with 4 h vehicle/4OH-TAM treatment and monomethyl succinate (10 mM MMS) in HEL cell lines, showing the reduction of thrombopoietin-induced JAK2 phosphorylation by 4OH-TAM could be rescued by the addition of succinate in human JAK2V617F-mutated cell lines (n = 3 independent experiments). e-g Data are mean + SEM; *p < 0.05, **p < 0.01, ***p < 0.001, One-way ANOVA and Dunnett’s test. e-g Data are mean + SEM; *p < 0.05, **p < 0.01, ***p < 0.001, One-way ANOVA and Dunnett’s test.

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