title: In vitro angiogenesis induced by tumor-endothelial cell co-culture in bilayered, collagen I hydrogel bioengineered tumors.
abstract: Although successful remission has been achieved when cancer is diagnosed and treated during its earliest stages of development, a tumor that has established neovascularization poses a significantly greater risk of mortality. The inability to recapitulate the complexities of a maturing in vivo tumor microenvironment in an in vitro setting has frustrated attempts to identify and test anti-angiogenesis therapies that are effective at permanently halting cancer progression. We have established an in vitro tumor angiogenesis model driven solely by paracrine signaling between MDA-MB-231 breast cancer cells and telomerase-immortalized human microvascular endothelial (TIME) cells co-cultured in a spatially relevant manner. The bilayered bioengineered tumor model consists of TIME cells cultured as an endothelium on the surface of an acellular collagen I hydrogel under which MDA-MB-231 cells are cultured in a separate collagen I hydrogel. Results showed that TIME cells co-cultured with the MDA-MB-231 cells demonstrated a significant increase in cell number, rapidly developed an elongated morphology, and invasively sprouted into the underlying acellular collagen I layer. Comparatively, bioengineered tumors cultured with less aggressive MCF7 breast cancer cells did not elicit an angiogenic response. Angiogenic sprouting was demonstrated by the formation of a complex capillary-like tubule network beneath the surface of a confluent endothelial monolayer with lumen formation and anastomosing branches. In vitro angiogenesis was dependent on vascular endothelial growth factor secretion, matrix concentration, and duration of co-culture. Basic fibroblast growth factor supplemented to the co-cultures augmented angiogenic sprouting. The development of improved preclinical tumor angiogenesis models, such as the one presented here, is critical for accurate evaluation and refinement of anti-angiogenesis therapies.
authors.affiliation: 1 School of Biomedical Engineering and Sciences, Virginia Polytechnic Institute-Wake Forest University , Blacksburg, Virginia.
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Szot
authors.forename: Cara F
authors.initials: CF
authors.lastname: Buchanan
authors.forename: Joseph W
authors.initials: JW
authors.lastname: Freeman
authors.forename: Marissa Nichole
authors.initials: MN
authors.lastname: Rylander
mesh_terms: D057005:Bioengineering; D002452:Cell Count; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D048430:Cell Shape; D018920:Coculture Techniques / Q000379:methods*; D024042:Collagen Type I / Q000378:metabolism / Q000494:pharmacology*; D042783:Endothelial Cells / Q000187:drug effects / Q000473:pathology*; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000494:pharmacology*; D009369:Neoplasms / Q000378:metabolism / Q000473:pathology*; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D024042:Collagen Type I; D042461:Vascular Endothelial Growth Factor A; D016222:Fibroblast Growth Factor 2; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate