title: Genome-wide expression analysis using microarray identified complex signaling pathways modulated by hypoxia in nasopharyngeal carcinoma.
abstract: Previously, we showed that hypoxia-inducible factor (HIF)-1alpha, HIF-2alpha, carbonic anhydrase IX (CA IX), and vascular endothelial growth factor (VEGF) were frequently coexpressed in tumor biopsies from patients of nasopharyngeal carcinoma (NPC) and were associated with poor outcome after radiotherapy. Here, we further studied hypoxic induction of HIF-1alpha, HIF-2alpha, CA IX, and VEGF in NPC cell lines, investigated hypoxia-modulated gene expression in NPC cell lines by Affymetrix GeneChip Array expression profiling, and identified pathways influenced by hypoxia and novel genes not previously recognized as hypoxia-inducible. Differentially regulated genes under hypoxia were identified genome widely and selected genes validated by RT-PCR. We found that hypoxia induced HIF-1alpha, CA IX and VEGF expression but not HIF-2alpha in NPC cells. Microarray expression analysis showed that 222 genes were commonly up-regulated and 137 genes down-regulated in hypoxic-treated CNE-2 and HONE-1 cells. Hypoxia induced broad changes of both up- and down-regulated gene expressions involved in diverse biological processes in NPC cells. Elucidation of the coordinated functions modulated by hypoxia could lead to a better understanding of the clinical significance of the hypoxic tumor phenotype.
authors.affiliation: Department of Clinical Oncology, State Key Laboratory in Oncology in South China, Sir YK Pao Centre for Cancer, Hong Kong Cancer Institute, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong.
authors.forename: Fion L
authors.initials: FL
authors.lastname: Sung
authors.forename: Edwin P
authors.initials: EP
authors.lastname: Hui
authors.forename: Qian
authors.initials: Q
authors.lastname: Tao
authors.forename: Hongyu
authors.initials: H
authors.lastname: Li
authors.forename: Nancy B Y
authors.initials: NB
authors.lastname: Tsui
authors.forename: Y M Dennis
authors.initials: YM
authors.lastname: Lo
authors.forename: Brigette B Y
authors.initials: BB
authors.lastname: Ma
authors.forename: Ka F
authors.initials: KF
authors.lastname: To
authors.forename: Adrian L
authors.initials: AL
authors.lastname: Harris
authors.forename: Anthony T C
authors.initials: AT
authors.lastname: Chan
mesh_terms: D000951:Antigens, Neoplasm / Q000378:metabolism; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism; D000071231:Carbonic Anhydrase IX; D002256:Carbonic Anhydrases / Q000378:metabolism; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D015870:Gene Expression; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D009303:Nasopharyngeal Neoplasms / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D015398:Signal Transduction; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D000099162:Endothelial PAS Domain-Containing Protein 1
chemical_list: D000951:Antigens, Neoplasm; D051792:Basic Helix-Loop-Helix Proteins; D000071231:Carbonic Anhydrase IX; D002256:Carbonic Anhydrases; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D042461:Vascular Endothelial Growth Factor A; D000099162:Endothelial PAS Domain-Containing Protein 1; C089226:CA9 protein, human