Abstract 6000: A millifluidic culture platform for quantifying premetastatic niche cultivation in quiescent organ stroma induced by real-time transport of tumor-derived factors
Authors: Olsen Elisabet A. , Ahmad Omar M. , Sweeney Bradley , Culp Caroline C. , Maurice Yasmin V. , Burow Matthew R. , Mondrinos Mark 
Published: June 2022

Abstract
Progression to metastasis contributes to the poor overall survival of patients diagnosed with aggressive cancers such as triple negative breast cancer (TNBC). Tumor-derived factors (TDF) induce pathological changes in distant organ niches that render these organs more receptive to colonization by disseminated tumor cells. This process, termed premetastatic niche (PMN) cultivation, is characterized in part by pathological activation of stromal cells and induction acute extracellular matrix (ECM) deposition. There is an urgent and unmet need for models of PMN cultivation in human cancers to accelerate the discovery of mechanisms and develop PMN-targeting therapies. We engineered 3D culture models of aggressive carcinoma and quiescent organ interstitium and integrated them in a millifluidic device that enables interconnected coculture. Our devices are engineered for ease of adoption by labs with experience culturing cells and organoids in 3D hydrogels. Cultures can be performed in static, with continuous gravity-driven flow, or with a rocker for recirculating flow. Here we present a form of the model in which a patient-derived triple negative breast cancer microenvironment is linked with a quiescent lung interstitium. Fibroblast activation and ECM synthesis indicative of PMN cultivation are quantified relative to a physiological resting state. All device cultures were maintained with fibroblast growth medium containing 0.1% FBS and 1% ITS which maintains the lung compartment in a quiescent state in the absence of endogenous activating factors in the system. The TME compartment in our devices exhibited features of aggressive cancers after 7 days of culture including widespread 3D invasion of tumor cells and formation of a dense stroma comprised of myofibroblast-like CAF with prominent smooth muscle actin (SMA) cytoskeleton and nuclear translocation of activated Yes-associated protein 1 (aYAP1). These cellular features of the engineered tumor microenvironment were accompanied by a dense anisotropic matrix of newly-synthesized fibronectin. TNBC-derived factors transported in the system induced PMN cultivation in the lung compartment by 7 days, as evidenced by quantitative increases in focal deposition of fibronectin and a spectrum of activated phenotypes defined by SMA and aYAP1 expression patterns in previously quiescent fibroblasts. Thus, we have captured cancer-induced changes in the density and architecture of newly-synthesized ECM in a distant tissue that would support tumor cell adhesion.
Citation Format: Elisabet A. Olsen, Omar M. Ahmad, Bradley Sweeney, Caroline C. Culp, Yasmin V. Maurice, Matthew R. Burow, Mark Mondrinos. A millifluidic culture platform for quantifying premetastatic niche cultivation in quiescent organ stroma induced by real-time transport of tumor-derived factors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6000.