Glucocorticoids paradoxically facilitate steroid resistance in T cell acute lymphoblastic leukemias and thymocytes
Lauren K. Meyer, Benjamin J. Huang, Cristina Delgado-Martin, Ritu P. Roy, Aaron Hechmer, Anica M. Wandler, Tiffaney L. Vincent, Paolo Fortina, Adam B. Olshen, Brent L. Wood, Terzah M. Horton, Kevin M. Shannon, David T. Teachey, Michelle L. Hermiston
Lauren K. Meyer, Benjamin J. Huang, Cristina Delgado-Martin, Ritu P. Roy, Aaron Hechmer, Anica M. Wandler, Tiffaney L. Vincent, Paolo Fortina, Adam B. Olshen, Brent L. Wood, Terzah M. Horton, Kevin M. Shannon, David T. Teachey, Michelle L. Hermiston
View: Text | PDF
Research Article Oncology

Glucocorticoids paradoxically facilitate steroid resistance in T cell acute lymphoblastic leukemias and thymocytes

Abstract

Glucocorticoids (GCs) are a central component of therapy for patients with T cell acute lymphoblastic leukemia (T-ALL), and although resistance to GCs is a strong negative prognostic indicator in T-ALL, the mechanisms of GC resistance remain poorly understood. Using diagnostic samples from patients enrolled in the frontline Children’s Oncology Group (COG) T-ALL clinical trial AALL1231, we demonstrated that one-third of primary T-ALLs were resistant to GCs when cells were cultured in the presence of IL-7, a cytokine that is critical for normal T cell function and that plays a well-established role in leukemogenesis. We demonstrated that in these T-ALLs and in distinct populations of normal developing thymocytes, GCs paradoxically induced their own resistance by promoting upregulation of IL-7 receptor (IL-7R) expression. In the presence of IL-7, this augmented downstream signal transduction, resulting in increased STAT5 transcriptional output and upregulation of the prosurvival protein BCL-2. Taken together, we showed that IL-7 mediates an intrinsic and physiologic mechanism of GC resistance in normal thymocyte development that is retained during leukemogenesis in a subset of T-ALLs and is reversible with targeted inhibition of the IL-7R/JAK/STAT5/BCL-2 axis.

Authors

Lauren K. Meyer, Benjamin J. Huang, Cristina Delgado-Martin, Ritu P. Roy, Aaron Hechmer, Anica M. Wandler, Tiffaney L. Vincent, Paolo Fortina, Adam B. Olshen, Brent L. Wood, Terzah M. Horton, Kevin M. Shannon, David T. Teachey, Michelle L. Hermiston

×

Figure 3

STAT5B, but not STAT5A, mediates the upregulation of BCL-2 expression in cells exposed to the combination of DEX and IL-7.

Options: View larger image (or click on image) Download as PowerPoint
STAT5B, but not STAT5A, mediates the upregulation of BCL-2 expression in...
(A) Evaluation of STAT5A and STAT5B expression by Western blotting in independent scrambled control (S1–S4) and STAT5 single-KO (A1–A4 or B1–B4) and double-KO (AB1–AB4) CCRF-CEM cell clones (n = 4 per genotype). (B) Viability of independent scrambled control and STAT5-KO CCRF-CEM cell clones (n = 4 per genotype) treated with 100 nM DEX with or without 25 ng/mL IL-7 for 72 hours. (C) Venn diagram depicting the overlap between the top differentially expressed genes among scrambled control CCRF-CEM cell clones (n = 4) treated with DEX versus DEX plus IL-7 and STAT5B target genes. (D and E) Fold change in the fragments per kilobase per million mapped reads (FPKM) values for (D) BCL2 transcript and (E) ARHGEF3 transcript levels as determined by RNA-Seq analysis of scrambled control cells (n = 4) and STAT5A/B double-KO (n = 4) CCRF-CEM cell clones treated in the absence or presence of 100 ng/mL IL-7 and/or 1 μM DEX for 16 hours. (F) ΔMFI of BCL-2 protein expression in scrambled control (n = 4) and STAT5-KO (n = 4) CCRF-CEM cell clones treated with 100 ng/mL IL-7 and 1 μM DEX relative to 100 ng/mL IL-7 alone for 48 hours. (G) BCL2L11 and BCL2 transcript expression in CCRF-CEM cells cultured in the absence or presence of 1 μM DEX, 100 ng/mL IL-7, and/or 10 μg/mL CHX for 16 hours as determined by qPCR performed in technical triplicate. *P < 0.05, **P < 0.01, and ****P < 0.0001, by paired t test (B), 2-sample t test (D and E), or 1-way ANOVA with Tukey’s method for multiple comparisons adjustment (F and G). With the exception of the RNA-Seq experiment, all data are representative of 3 independent experiments.