Assembly and Characterization of 3D, Vascularized Breast Cancer Tissue Mimics

Drug development platforms such as two-dimensional (2D) in vitro cell culture systems and in vivo animal studies do not accurately predict human in vivo effectiveness of candidate therapeutics [1]. Cell culture systems have limited similarities to primary human cells and tissues as only one cell type is employed and animal studies have a generally limited ability to recapitulate human drug response as different species have differences in metabolism, physiology, and behavior. Mike Leavitt, a former U.S. Secretary of Health and Human Services, has stated that “currently, nine out of ten experimental drugs fail in clinical studies because we cannot accurately predict how they will behave in people based on laboratory and animal studies” [2]. Therefore, this research project is focused on developing an in vitro platform to test candidate therapeutics for more efficacious predictions of human response. We have fabricated a three-dimensional (3D) breast cancer tissue volume containing a vascular network. This vascular network is necessary because current in vitro systems (e.g., rotating bioreactors, suspension of spheroids, and growth on a porous scaffold) are limited in size (1–2 mm) by their absence of micrometer-scale blood flow micro-channels that allow for oxygen and nutrient diffusion into the tissue [4]. The extracellular matrix scaffold has been developed to mimic the native extracellular matrix and includes relevant cell types (e.g., human breast cancer epithelial cells and human breast fibroblasts) along with the prefabricated vascular network (prevascularization). These systems are intended to support long-term growth, recapitulate physiological tissue function, and accurately model response to treatment. It is hypothesized that the development of reproducible tissue volumes will transform breast cancer drug development by providing reliable, cost-effective models that can more accurately predict therapeutic efficacy than current preclinical in vivo and in vitro models.