Modeling tissues in vitro has long consisted of two-dimensional (2D) monolayer cultures grown in a dish, flask, or multi-well plate. While these methods remain adequate for some applications, the advent of personalized cancer therapies has necessitated the development of more complex models that more accurately represent the in vivo environment. Attempting to characterize tumor cell biology and response to candidate pharmaceuticals in 2D cultures has led to results that fail to translate to clinical therapies. A key source of this failure is the loss of cell diversity due to selective pressure resulting in cell populations that favor adhering to a rigid substrate. Three-dimensional (3D) cell culture methods have produced models that capture many of the dynamics of the in vivo tissue environment. Patient-derived organoids (PDOs) are quickly becoming the most attractive solution for creating predictive, patient-specific tumor models in vitro. Typically grown as spheroids, these models still present limitations in terms of cell survival and recapitulation of tumor development.
Lena Biosciences has previously developed complex, vascularized tissue models using patented 3D scaffolds and a perfusion system. Hepatocytes grown in this system demonstrated increased cell viability and recovery of cytochrome P450 enzyme activity compared to 2D controls. Integral to the perfusion system is a pure, synthetic liquid that is twice as dense as and immiscible with cell culture medium and reagents. It is permissive to atmospheric gases, providing a gas-rich, liquid-liquid interface below 3D cultures maintained in the system. We hypothesized that PDOs could be cultured without a 3D scaffold, directly at the interface between the cell culture medium and this synthetic liquid. A specific preparation of this interface resulted in lung-derived PDOs that spontaneously formed dense, 3D, tissue-like structures that showed increased viability (as measured by a 50% reduction in LDH release) and cellular respiration (three-fold increase as measured by an alamarBlue assay). Ongoing studies are focused on characterizing PDOs from other patients and other tissues as they develop in long-term in vitro studies. Should this PDO model prove to be a faithful representation of in vivo tumor development, this system would be ideal for applications such as testing drug efficacy and studying mechanisms of tumor metastasis.
Citation Format: James T. Shoemaker, Katherine R. Richardson, Jamie Arnst, Adam Marcus, Jelena Vukasinovic. Characterization of patient-derived organoids cultured on a gas-rich, liquid-liquid interface [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 54.