Biallelic TET2 mutations confer sensitivity to 5′-azacitidine in acute myeloid leukemia
Friedrich Stölzel, et al.
Friedrich Stölzel, et al.
View: Text | PDF
Research Article Hematology

Biallelic TET2 mutations confer sensitivity to 5′-azacitidine in acute myeloid leukemia

Abstract

Precision medicine can significantly improve outcomes for patients with cancer, but implementation requires comprehensive characterization of tumor cells to identify therapeutically exploitable vulnerabilities. Here, we describe somatic biallelic TET2 mutations in an elderly patient with acute myeloid leukemia (AML) that was chemoresistant to anthracycline and cytarabine but acutely sensitive to 5′-azacitidine (5′-Aza) hypomethylating monotherapy, resulting in long-term morphological remission. Given the role of TET2 as a regulator of genomic methylation, we hypothesized that mutant TET2 allele dosage affects response to 5′-Aza. Using an isogenic cell model system and an orthotopic mouse xenograft, we demonstrate that biallelic TET2 mutations confer sensitivity to 5′-Aza compared with cells with monoallelic mutations. Our data argue in favor of using hypomethylating agents for chemoresistant disease or as first-line therapy in patients with biallelic TET2-mutated AML and demonstrate the importance of considering mutant allele dosage in the implementation of precision medicine for patients with cancer.

Authors

Friedrich Stölzel, Sarah E. Fordham, Devi Nandana, Wei-Yu Lin, Helen Blair, Claire Elstob, Hayden L. Bell, Brigitte Mohr, Leo Ruhnke, Desiree Kunadt, Claudia Dill, Daniel Allsop, Rachel Piddock, Emmanouela-Niki Soura, Catherine Park, Mohd Fadly, Thahira Rahman, Abrar Alharbi, Manja Wobus, Heidi Altmann, Christoph Röllig, Lisa Wagenführ, Gail L. Jones, Tobias Menne, Graham H. Jackson, Helen J. Marr, Jude Fitzgibbon, Kenan Onel, Manja Meggendorfer, Amber Robinson, Zuzanna Bziuk, Emily Bowes, Olaf Heidenreich, Torsten Haferlach, Sara Villar, Beñat Ariceta, Rosa Ayala Diaz, Steven J. Altschuler, Lani F. Wu, Felipe Prosper, Pau Montesinos, Joaquin Martinez-Lopez, Martin Bornhäuser, James M. Allan

×

Figure 5

Differential gene expression in AML cells with monoallelic and biallelic TET2 mutations.

Options: View larger image (or click on image) Download as PowerPoint
Differential gene expression in AML cells with monoallelic and biallelic...
(A) Heatmap showing the top 1,500 differentially expressed transcripts in parental TET2 monoallelic HEL cell clones (HEL TET2 monoallelic; n = 3) and TET2 CRISPR/Cas9-mutated HEL cell clones (HEL TET2 biallelic; n = 3). Horizontal rows represent individual transcripts and each vertical column represents a cell clone. Color indicates relative expression, with downregulated and upregulated transcripts indicated in blue and red, respectively. (B) Volcano plot demonstrating significant differential gene expression (P < 0.05 and |log2FC| ≥ 0.3) in TET2 CRISPR/Cas9-mutated HEL cell clones (HEL TET2 biallelic; n = 3) relative to parental HEL clones with monoallelic TET2 mutation (HEL TET2 monoallelic; n = 3). Plot was constructed using log2FC values and adjusted P values, and points represent individual gene transcripts. Shown are 326 significantly downregulated transcripts (blue) and 369 significantly upregulated transcripts (red). Nonsignificant transcripts (P ≥ 0.05) are represented by gray points. Genes with particularly significant differential expression are labeled. (C) Heatmap showing differential expression of components of the spliceosomal snRNP complex (GO:009752) in parental TET2 monoallelic HEL cell clones (HEL TET2 monoallelic; n = 3) and TET2 CRISPR/Cas9-mutated HEL cell clones (HEL TET2 biallelic; n = 3). Horizontal rows represent genes and each vertical column represents a cell clone. Color indicates relative expression, as in A. (D) Transcript expression (expressed as counts per million [CPM] reads) of LSM8 (top) and ABCB1 (bottom) in parental TET2 monoallelic HEL cell clones (HEL TET2 monoallelic; unfilled bars) and TET2 CRISPR/Cas9-mutated HEL cell clones (HEL TET2 biallelic; filled bars). Data represent the mean and SD of indicated number of clones. P values are from differential expression analysis. Western blots to the right of the charts show corresponding protein expression in the individual cell clones included in RNA-sequencing analysis. α-Tubulin was used as a loading control.