Novel HIF2A mutations disrupt oxygen sensing, leading to polycythemia, paragangliomas, and somatostatinomas - PubMed (original) (raw)

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Novel HIF2A mutations disrupt oxygen sensing, leading to polycythemia, paragangliomas, and somatostatinomas

Chunzhang Yang et al. Blood. 2013.

Abstract

Hypoxia-inducible factors (HIFs) control the cellular response to hypoxia and, when dysregulated, contribute to tumorigenesis. Previously, we identified 2 gain-of-function somatic mutations in patients presenting with multiple paragangliomas or somatostatinomas, and polycythemia. Here, we report 2 additional unique HIF2A mutations, which disrupt the hydroxylation domain recognized by prolyl hydroxylase domain-2 containing protein, leading to stabilization of HIF-2α and increased expression of hypoxia-related genes.

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Figures

Figure 1

Figure 1

Novel HIF2A mutations disrupt cellular oxygen sensing. (A) Mutation analysis showing heterozygous mutation of HIF2A gene in tumor specimen but not adjacent normal tissue. (B) Peptide sequence alignment of prolyl hydroxylation domain of HIF-2α. (C) Electrostatic changes of single-site mutations in PHD2-HIF-α complex. Interaction between leucine (L) and tyrosine (Y) and PHD2 residues (top) and electrostatic changes resulting from L529P and Y532C substitution (bottom; red, negative; blue, positive; ±5 kT/e) (D) Peptide hydroxylation assay through matrix-assisted laser desorption ionization-time-of-flight showing absent hydroxylation in ΔHIF-2α-L529P mutant. (E) Peptide binding assay of radioactive labeled VHL and HIF-2α-derived peptides, showing reduced VHL binding in HIF-2α mutant. (F) Immunoprecipitation assay showing decreased VHL binding in HIF-2α mutant.

Figure 2

Figure 2

HIF2A mutation lead to pseudohypoxic change and tumor formation. (A) Immunoprecipitation assay measuring HIF-2α ubiquitination, showing decreased protein ubiquitination in mutant protein. (B) CHX assay measuring HIF-2α stability, showing elongated protein half-life. (C) Immunohistochemistry staining of HIF-2α in tumor specimens, showing increased HIF-2α protein in tumors. (D) Quantitative polymerase chain reaction assay showing increased hypoxia-related gene expression in tumor specimen. (E) Chromatin immunoprecipitation assay showing intact DNA-binding efficiency of mutant HIF-2α.

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