Abstract 337: A metastatic phenotype is reproduced in spheroids containing patient-specific cancer cells and mesenchymal stem cells
Authors: Shvartsman Dmitry , Pepicelli Amy , Deems Liam , Deems David , Agoston Elin S. , Shahar Amit 
Published: September 2020

Abstract
Reproducible, scalable, and patient-specific 3D models of the tumor microenvironment are required to study tumor growth, metastasis and dormancy. In this study, patient-derived cancer cells, mesenchymal stem cells (MSCs), and optimization of the oxygen level and extracellular matrix (ECM) were incorporated in the development of a spheroid system using 5 cancer cell models (pancreatic [Panc], lung adenocarcinoma [LA], colon adenocarcinoma [CA], endometrioid ovarian [EO] and high-grade serous carcinoma [HGSC]). The cell models were isolated and scaled up using a feeder-free culture medium in either ambient oxygen (approximately 21% O2) or hypoxic (5% O2) conditions, depending on the individual model requirements. Cell migration was assessed via monolayer scratch assays, and the relative rates were compared to the T stage of the tumor from which the models were derived. To assess spheroid formation, the 5 models were cultured in ECM-containing medium. The Panc and HGSC spheroids were also generated with the addition of MSCs at ratios of 1-100 MSCs per 100 cancer cells. The relative rates of migration of the cell models in ambient oxygen (CA &gt; EO ≈ Panc &gt; HGSC ≈ LA) differed significantly from that in 5% O2 (CA = Panc = HGSC &gt; EO &gt; LA). Interestingly, the T stage of the original tumors (CA = Panc = HGSC &gt; LA &gt; EO) correlated more closely to the relative rate of cell migration when the cell models were cultured in 5% compared to 21% O2. When cultured in a 3D (spheroid) format containing ECM, the Panc and EO models demonstrated increased invasion into the surrounding ECM compared to the LA, HGSC, and CA models. The addition of MSCs into the LA model dramatically increased the invasive phenotype of the LA model. A seeding ratio of 1:100 MSC:LA cells enabled spheroid formation and invasion into the ECM, previously unobserved for the LA model in this format. The Panc model became extremely aggressive with respect to invasion into the ECM, at a ratio as low as 1:100 MSCs to cancer cells. In pilot studies with the Panc and HGSC models, spheroid size and invasion into the ECM increased upon adding the MSCs. Spheroid diameter increased by approximately 30%, and there was a notable increase in invasiveness of the already mobile and invasive Panc cancer cells into the surrounding ECM. We present here an efficient, patient-specific, spheroid model system representing dormant and metastatic tumor states that is suitable for studying antitumor drug response, personalized therapy, and disease mechanisms. The relative rates of cell migration positively correlated with the T stage of the original tumors in the more physiologically-relevant oxygen condition (5%), underscoring the need to optimize this parameter during model development. Continued optimization will include incorporating tissue-specific ECMs from lung, liver and pancreas, and assessing the robustness and scalability of these models for high-throughput drug screens.
Citation Format: Dmitry Shvartsman, Amy Pepicelli, Liam Deems, David Deems, Elin S. Agoston, Amit Shahar. A metastatic phenotype is reproduced in spheroids containing patient-specific cancer cells and mesenchymal stem cells [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 337.