Abstract 6786: Assessment of immune cell infiltration and cancer metastatic potential in Akura™ Immune Flow Chip - A microfluidic 3D spheroid system
Authors: Häfeli Tamara , Riss Silas , Lohasz Christian , Hasanova Dzhansu , Lützow Svenja , Hölting Lisa , Rudnik Michal , Linke Franziska , van Weerden Wytske M , Ligeon Laure-Anne , Hierlemann Andreas , Modena Mario , Frey Olivier 
Published: March 2024

Abstract
Evaluation of novel therapeutics often fails to reliably predict severe complications in patients, especially when circulating cells are involved. The reasons may include inter-species differences upon using animal models or the lack of relevant in vitro systems. Moreover, existing in vitro systems mostly rely on static investigations of different cell types leading to overestimation of effects due to non-representative cell-tissue interactions. The incorporation of medium flow may facilitate to mimic physiological conditions more closely. To tackle current limitations of perfused organ-on-chip approaches, we developed a microfluidic chip and operation concept, which prevents undesired sedimentation and accumulation of cells in suspensions. The Akura™ Immune Flow platform was designed to study flow-dependent recruitment of circulating cells to different tissue spheroids via gravity-driven perfusion over several days. The Akura™ Immune Flow platform features standardized formats for co-culturing up to seven spheroids with suspended cells in each microfluidic channel. On-chip staining protocols enabled monitoring of the co-culture. The system allowed for application and extractions of cellular components and liquid for further off-chip analysis. Primary tissue and cell line spheroids (liver and tumor) could be retained in the respective chambers and remained viable over six to 14 days. Circulating cells were kept viable and in suspension for up to six days (PBMCs) and14 days (Prostate Cancer (PCa) cells) respectively. PBMCs were not activated by flow-induced shear forces. Unspecific stimulation of T-cells led to physiological expression of early and late activation markers (CD69 and CD25), which were detected by flow cytometry in periodically collected cells. Multi-photon microscopy imaging confirmed that PBMCs interacted with and infiltrated into 3D tumor spheroids. Application of PCa cells to primary liver spheroids, cultured in Akura™ Immune Flow chips allowed for assessment of their invasive potential. Confocal imaging revealed adhesion of cancer cells to the liver spheroids and offers the potential to study the ability of tissue invasion at later time points. The simple design of the chip facilitates user-friendly operation and high-throughput implementation in cancer research and drug testing. The selected applications support the relevance of using flow solutions for physiologically more complex processes. This work constitutes an important step towards device application as a tool for basic research as well as for efficacy studies of immunotherapeutic drug candidates
Citation Format: Tamara Häfeli, Silas Riss, Christian Lohasz, Dzhansu Hasanova, Svenja Lützow, Lisa Hölting, Michal Rudnik, Franziska Linke, Wytske M van Weerden, Laure-Anne Ligeon, Andreas Hierlemann, Mario Modena, Olivier Frey. Assessment of immune cell infiltration and cancer metastatic potential in Akura™ Immune Flow Chip - A microfluidic 3D spheroid system [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6786.