title: Tumor-induced angiogenesis studied in confrontation cultures of multicellular tumor spheroids and embryoid bodies grown from pluripotent embryonic stem cells.
abstract: Tumor vascularization is the rate-limiting step for the progression of cancer. Differential steps of tumor-induced angiogenesis were studied by a novel in vitro confrontation culture of avascular multicellular prostate tumor spheroids and embryoid bodies grown from pluripotent embryonic stem (ES) cells. Vascularization in embryoid bodies started on day 5 of cell culture and was paralleled by down-regulation of hypoxia-inducible factor 1 alpha (HIF-1 alpha) and vascular endothelial growth factor (VEGF). In parallel, a dissipation of gradients in the pericellular oxygen pressure was observed as measured by O(2)-sensitive microelectrodes. After 24--48 h of confrontation culture, cells positive for platelet endothelial cell adhesion molecule (PECAM-1) became visible in the contact region between the embryoid body and the tumor spheroid and sprouted within the confrontation cultures during subsequent days. Tumor-induced angiogenesis resulted in growth stimulation of tumor spheroids, disappearance of central necrosis and a reduction of the pericellular oxygen pressure. Furthermore, tumor vascularization resulted in elevated levels of HIF-1 alpha, VEGF, heat shock protein 27 (HSP27), and P-glycoprotein. Tumor-induced angiogenesis may augment the oxygen consumption in tumors resulting in an increased expression of hypoxia-related, proangiogenic genes as well as of HSP27 and P-glycoprotein, which are involved in a multidrug resistance phenotype.
authors: Department of Neurophysiology, University of Cologne, D-50931 Cologne, Germany.
authors: M
authors: M
authors: Wartenberg
authors: F
authors: F
authors: Dönmez
authors: F C
authors: FC
authors: Ling
authors: H
authors: H
authors: Acker
authors: J
authors: J
authors: Hescheler
authors: H
authors: H
authors: Sauer
mesh_terms: D000818:Animals; D018920:Coculture Techniques; D004268:DNA-Binding Proteins / Q000378:metabolism; D016228:Endothelial Growth Factors / Q000378:metabolism; D006801:Humans; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D007150:Immunohistochemistry; D008222:Lymphokines / Q000378:metabolism; D051379:Mice; D018919:Neovascularization, Physiologic / Q000502:physiology*; D009687:Nuclear Proteins / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D018874:Spheroids, Cellular / Q000502:physiology*; D013234:Stem Cells / Q000502:physiology*; D013997:Time Factors; D014157:Transcription Factors; D014407:Tumor Cells, Cultured; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
chemical_list: D004268:DNA-Binding Proteins; D016228:Endothelial Growth Factors; C497442:HIF1A protein, human; C497443:Hif1a protein, mouse; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008222:Lymphokines; D009687:Nuclear Proteins; D014157:Transcription Factors; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D010100:Oxygen