Open Access Research

Development and characterization of a high-throughput in vitro cord formation model insensitive to VEGF inhibition

Beverly L Falcon1, Belinda O’Clair4, Don McClure2, Glenn F Evans1, Julie Stewart3, Michelle L Swearingen1, Yuefeng Chen1, Kevin Allard4, Linda N Lee1, Kuldeep Neote1, Dyke P McEwen4, Mark T Uhlik1 and Sudhakar Chintharlapalli1*

Author Affiliations

1 Eli Lilly and Company, Department of Cancer Angiogenesis, Lilly Corporate Center, Indianapolis, IN, 46285, USA

2 Eli Lilly and Company, Department of BioTDR, Lilly Corporate Center, Indianapolis, IN, 46285, USA

3 Eli Lilly and Company, Department of Tailored Therapeutics, Lilly Corporate Center, Indianapolis, IN, 46285, USA

4 Essen BioScience, Inc., 300 West Morgan Road, Ann Arbor, MI, 48108, USA

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Journal of Hematology & Oncology 2013, 6:31  doi:10.1186/1756-8722-6-31

Published: 27 April 2013

Abstract

Background

Anti-VEGF therapy reduces tumor blood vessels, however, some vessels always remain. These VEGF insensitive vessels may help support continued tumor growth and metastases. Many in vitro assays examining multiple steps of the angiogenic process have been described, but the majority of these assays are sensitive to VEGF inhibition. There has been little focus on the development of high-throughput, in vitro assays to model the vessels that are insensitive to VEGF inhibition.

Methods

Here, we describe a fixed end-point and kinetic, high-throughput stem cell co-culture model of cord formation.

Results

In this system, cords develop within 24 hours, at which point they begin to lose sensitivity to VEGF inhibitors, bevacizumab, and ramucirumab. Consistent with the hypothesis that other angiogenic factors maintain VEGF-independent vessels, pharmacologic intervention with a broad spectrum anti-angiogenic antagonist (suramin), a vascular disrupting agent (combretastatin), or a combination of VEGF and Notch pathway inhibitors reduced the established networks. In addition, we used our in vitro approach to develop an in vivo co-implant vasculogenesis model that connects with the endogenous vasculature to form functional blood vessels. Similar to the in vitro system, over time these vessels become insensitive to VEGF inhibition.

Conclusion

Together, these models may be used to identify novel drugs targeting tumor vessels that are not sensitive to VEGF inhibition.

Keywords:
Angiogenesis; Vascular endothelial growth factor (VEGF); Adipose derived stem cells (ADSC); Endothelial colony forming cells (ECFC)