A human colorectal cancer chip recapitulates aspects of CRC biology On-chip imaging and metabolomic effluent analyses offer insight into progression Organ-on-chip conditions induce phenotypic heterogeneity compared to 2D cultures Stromal cell cross talk and mechanical forces increase tumor cell intravasation
Non-small cell lung cancer (NSCLC) patients with activating EGFR mutations are often successfully treated with EGFR tyrosine kinase inhibitor (TKI) such as erlotinib; however, treatment resistance inevitably occurs. Given tumor metabolism of glucose and therapeutic response are intimately linked, we explored the metabolic differences between isogenic erlotinib-sensitive and -resistant NSCLC cell lines. We discovered that the growth of erlotinib-resistant cells is more sensitive to glucose deprivation. Seahorse metabolic assay revealed erlotinib-resistant cells have lower spare respiratory capacity (SRC), an indicator of metabolic flexibility, compared to erlotinib-sensitive cells. Additionally, we found downstream components of mTORC2 signaling to be phosphorylated in erlotinib-resistant cells. Knockdown of an mTORC2 component, Rictor, enhanced the SRC and rescued the growth rate of erlotinib-resistant cells during glucose deprivation. Among NSCLCs with activating EGFR mutations, gene sets involved in glucose metabolism were enriched in patients with high expression of p-NDGR1, a readout of mTORC2 activity. Furthermore, overall survival was negatively correlated with p-NDRG1. Our work uncovers a link between mTORC2 and metabolic reprogramming in EGFR TKI-resistant cells and highlights the significance of mTORC2 in the progression of EGFR-mutated NSCLC.
The role of plasticity and epigenetics in shaping cancer evolution and response to therapy has taken center stage with recent technological advances including single cell sequencing. This Roadmap article is focused on state-of-the-art mathematical and experimental approaches to interrogate plasticity in cancer, and addresses the following themes and questions: is there a formal overarching framework that encompasses both non-genetic plasticity and mutation-driven somatic evolution? How do we measure and model the role of the microenvironment in influencing/controlling non-genetic plasticity? How can we experimentally study non-genetic plasticity? Which mathematical techniques are required or best suited? What are the clinical and practical applications and implications of these concepts?
Summary
Despite colorectal cancer’s (CRC) prevalence, its progression is not well understood. The microfluidic organ-on-chip (OOC) model described herein recreates the epithelial-endothelial tissue-tissue interface, fluid flow, and mechanical forces that exist
in vivo
,
making it an attractive model to understand and ultimately disrupt CRC intravasation. This protocol provides step-by-step details for tumor cell seeding to create a CRC-on-chip model, chip effluent collection and analysis, and on-chip imaging to monitor tumor cell invasion within a more physiologically relevant microenvironment.
For complete details on the use and execution of this protocol, please refer to
Strelez et al. (2021)
.
Mechanical forces in the tumor microenvironmental milieu are often understudied due to a lack of relevant preclinical model systems. Here we describe a microfluidic organ-on-chip platform that incorporates tissue-tissue interfaces and physical forces to aid in the examination of colorectal cancer (CRC) progression. A major advantage of this model is the ability to mimic peristalsis, a physiological process occurring in the gut. Live-cell imaging with a 3D printed organ-on-chip cradle was used to quantify the number of CRC cells that have invaded from the epithelial channel into the vascular channel over time. We determined that peristalsis-like motions in our organ-on-chip model enhanced the invasion capacity of CRC cells, mimicking intravasation. We subsequently examined the effluent media in stretched compared to non-stretched conditions using mass spectrometry based metabolomics and discovered an increase in the secretion of gamma-aminobutyric acid (GABA) by CRC cells, implicating peristalsis-mediated tumor cell invasion with neurotransmitter release. Inhibitors targeting the GABA-A receptor reversed the observed tumor cell invasion phenotype when cells were subjected to peristalsis-like motions. Interestingly, even in the absence of peristalsis, tumor cell invasion was promoted when GABA agonists were introduced into the organ-on-chip system. This work reveals important interactions between CRC cells and their microenvironment, and that disrupting GABAergic signaling might be an approach to prevent or delay cancer progression.
Citation Format: Carly Strelez, Sujatha Chilakala, Kimya Ghaffarian, Ah Young Yoon, Jonathan Katz, Shannon M. Mumenthaler. Peristalsis-like mechanical stimuli in the intestinal milieu promotes colorectal cancer invasion through GABAergic signaling changes in an organ-on-chip platform [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 3858.
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