title: Overexpression of the natural antisense hypoxia-inducible factor-1alpha transcript is associated with malignant pheochromocytoma/paraganglioma.
abstract: Paragangliomas (PGLs) have widely different metastastic potentials. Two different types of PGLs can be defined by expression profiling. Cluster 1 PGLs exhibit VHL and/or succinate dehydrogenase (SDH) mutations and a pseudohypoxic phenotype. RET and neurofibromatosis type 1 (NF1) mutations occur in cluster 2 tumors characterized by deregulation of the RAS/RAF/MAP kinase signaling cascade. Sporadic PGLs can exhibit either profile. During sustained hypoxia, a natural antisense transcript of hypoxia-inducible factor 1 (aHIF) is expressed. The role of aHIF in the metastatic potential of PGL has not yet been investigated. The aim was to test the hypothesis that genotype-specific overexpression of aHIF is associated with an increased metastatic potential. Tumor samples were collected from 87 patients with PGL. Quantitative PCR was performed for aHIF, vascular endothelial growth factor (VEGF), aquaporin 3, cytochrome b561, p57Kip2, slit homolog 3, and SDHC. Expression was related to mutation status, benign versus malignant tumors, and metastasis-free survival. We found that both aHIF and VEGF were overexpressed in cluster 1 PGLs and in metastatic tumors. In contrast, slit homolog 3, p57Kip2, cytochrome b561, and SDHC showed overexpression in non-metastatic tumors, whereas no such difference was observed for aquaporin 3. Patients with higher expression levels of aHIF and VEGF had a significantly decreased metastasis-free survival. Higher expression levels of SDHC are correlated with an increased metastasis-free survival. In conclusion, we not only demonstrate a higher expression of VEGF in cluster 1 PGL, fitting a profile of pseudohypoxia and angiogenesis, but also of aHIF. Moreover, overexpression of aHIF and VEGF marks a higher metastatic potential in PGL.
authors.affiliation: Department of Laboratory Medicine, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB Nijmegen, The .
authors.forename: P N
authors.initials: PN
authors.lastname: Span
authors.forename: J U
authors.initials: JU
authors.lastname: Rao
authors.forename: S B J
authors.initials: SB
authors.lastname: Oude Ophuis
authors.forename: J W M
authors.initials: JW
authors.lastname: Lenders
authors.forename: F C G J
authors.initials: FC
authors.lastname: Sweep
authors.forename: P
authors.initials: P
authors.lastname: Wesseling
authors.forename: B
authors.initials: B
authors.lastname: Kusters
authors.forename: F H
authors.initials: FH
authors.lastname: van Nederveen
authors.forename: R R
authors.initials: RR
authors.lastname: de Krijger
authors.forename: A R M M
authors.initials: AR
authors.lastname: Hermus
authors.forename: H J L M
authors.initials: HJ
authors.lastname: Timmers
mesh_terms: D000293:Adolescent; D000310:Adrenal Gland Neoplasms / Q000235:genetics* / Q000378:metabolism; D000328:Adult; D000368:Aged; D051400:Aquaporin 3 / Q000096:biosynthesis / Q000235:genetics; D002648:Child; D050761:Cyclin-Dependent Kinase Inhibitor p57 / Q000096:biosynthesis / Q000235:genetics; D003573:Cytochrome b Group / Q000096:biosynthesis / Q000235:genetics; D018572:Disease-Free Survival; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000096:biosynthesis* / Q000235:genetics; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics; D008875:Middle Aged; D010673:Pheochromocytoma / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics; D012334:RNA, Neoplasm / Q000737:chemistry / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis / Q000235:genetics; D055815:Young Adult
chemical_list: C496027:AQP3 protein, human; D050761:Cyclin-Dependent Kinase Inhibitor p57; D003573:Cytochrome b Group; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008565:Membrane Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; C108096:SDHC protein, human; C498990:SLIT3 protein, human; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; C023646:cytochrome b561; D051400:Aquaporin 3