Designing Organoid Models to Monitor Cancer Progression, Plasticity and Resistance: The Right Set Up for the Right Question

SIMPLE SUMMARY: In this article, we describe a 3D model that supports the maintenance of cell polarity in cancer and normal cells by growing them on a collagen-coated microsupport. Instead of the spheroids model, the cells are directly positioned to adopt a basal/luminal organization, favoring differentiation and migration in the surrounding matrix. This model can be enriched with other components of the microenvironment such as fibroblasts and immune cells. For the proof-of-concept experiments, we treated mouse and human cell lines, then primary tumor cells from PDX, co-cultured with fibroblasts or immune cells. We monitored cell viability, proliferation and cytotoxicity using several light emission-based methods to obtain significant and reliable results, validating the method. ABSTRACT: The recent trend in 3D cell modeling has fostered the emergence of a wide range of models, addressing very distinct goals ranging from the fundamental exploration of cell–cell interactions to preclinical assays for personalized medicine. It is clear that no single model will recapitulate the complexity and dynamics of in vivo situations. The key is to define the critical points, achieve a specific goal and design a model where they can be validated. In this report, we focused on cancer progression. We describe our model which is designed to emulate breast carcinoma progression during the invasive phase. We chose to provide topological clues to the target cells by growing them on microsupports, favoring a polarized epithelial organization before they are embedded in a 3D matrix. We then watched for cell organization and differentiation for these models, adding stroma cells then immune cells to follow and quantify cell responses to drug treatment, including quantifying cell death and viability, as well as morphogenic and invasive properties. We used model cell lines including Comma Dβ, MCF7 and MCF10A mammary epithelial cells as well as primary breast cancer cells from patient-derived xenografts (PDX). We found that fibroblasts impacted cell response to Docetaxel and Palbociclib. We also found that NK92 immune cells could target breast cancer cells within the 3D configuration, providing quantitative monitoring of cell cytotoxicity. We also tested several sources for the extracellular matrix and selected a hyaluronan-based matrix as a promising alternative to mouse tumor basement membrane extracts for primary human cancer cells. Overall, we validated a new 3D model designed for breast cancer for preclinical use in personalized medicine.