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Solid tumors are frequently necrotic and hypoxic due to poor vascularization. Tumor cells adapt to hypoxia by modulating their phenotype. Key players in this process are the hypoxia-inducible factors (HIF-1alpha to 3alpha). HIFs are also expressed during normal development; for example, HIF-2alpha is specifically expressed and appears to be involved in the development of the murine sympathetic nervous system (SNS). Here, we demonstrate that HIF-2alpha protein is selectively present in human fetal week 8.5 SNS paraganglia. Neuroblastoma is derived from SNS precursors. In a subset of neuroblastomas, a spontaneous neuronal to neuroendocrine differentiation occurs in areas adjacent to necrotic zones. As HIF-2alpha activity has been associated not only with hypoxic but also with hypoglycemic conditions, we have investigated putative effects of hypoxia, glucose depletion, and HIF-2alpha on the neuroblastoma phenotype. HIF-2alpha was detected in hypoxic and in well-oxygenized neuroblastoma cells and tissue, presumably reflecting their embryonic features. With regard to differentiation, hypoxic cells lost their neuronal/neuroendocrine features and gained marker gene expression associated with an immature, neural crest-like phenotype. Low glucose potentiated the effect of hypoxia. These findings suggest that poorly vascularized neuroblastomas become immature and maintain a more aggressive phenotype, which possibly could involve a sustained stabilization and activation of HIF-2alpha.

Original publication

DOI

10.1016/j.yexcr.2004.10.003

Type

Journal article

Journal

Exp Cell Res

Publication Date

15/02/2005

Volume

303

Pages

447 - 456

Keywords

Base Sequence, Basic Helix-Loop-Helix Transcription Factors, Cell Differentiation, Cell Hypoxia, Cell Line, Tumor, DNA, DNA-Binding Proteins, Fetus, Gene Expression Regulation, Developmental, Gene Expression Regulation, Neoplastic, Glucose, Humans, Hypoxia-Inducible Factor 1, Hypoxia-Inducible Factor 1, alpha Subunit, Neuroblastoma, Nuclear Proteins, Paraganglia, Nonchromaffin, Sympathetic Nervous System, Transcription Factors