Human embryonic stem cells efficiently differentiate blood vessels, which allows using this in vitro model to study the interaction of blood vessels with adjacent tissues. Herein, we introduce confrontation cultures of human embryonic stem cells with multicellular tumor spheroids to investigate molecular mechanisms of tumor-induced angiogenesis. Vascularization of tumor tissue by the host is a prerequisite for tumor growth, which has led to the development of antiangiogenic therapy. This promising anti-cancer therapy intends to reduce, halt, or even regress tumor growth by deprivation from blood, oxygen, and nutrient supply. Confrontation cultures of human embryonic stem cells with multicellular tumor spheroids allow the investigation of the time course of endothelial cell invasion into the tumor tissue, the concomitant analysis of changes in angiogenesis-related gene expression, and analysis of the cellular microenvironment (i.e., pericellular oxygen pressure, tissue pH, and levels of tissue reactive oxygen species). The in vitro model of confrontation cultures is suitable for routine screening of antiangiogenic agents in pre-clinical trials and may be used to replace animal experiments applied in antiangiogenesis research.
Key Words: Confrontation culture; tumor-induced angiogenesis; human embryonic stem cell; multicellular tumor spheroid.
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