A Scaffold-Free 3-D Co-Culture Mimics the Major Features of the Reverse Warburg Effect In Vitro

• Published in: Cells (Basel, Switzerland) Vol. 9; no. 8; p. 1900
• Main Authors: Keller, Florian, Bruch, Roman, Schneider, Richard, Meier-Hubberten, Julia, Hafner, Mathias, Rudolf, Rüdiger
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 13.08.2020; MDPI
• Subjects: Adenocarcinoma - metabolism; Adenocarcinoma - pathology; Antibodies; Apoptosis; Autophagy; Biopsy; Cell culture; Coculture Techniques; Collagen; Colon cancer; Colonic Neoplasms - metabolism; Colonic Neoplasms - pathology; Colorectal cancer; Confocal microscopy; DNA microarrays; Fibroblasts; Fibroblasts - metabolism; Glucose - metabolism; Glycolysis; Hexokinase; HT29 Cells; Humans; Hypotheses; Immunofluorescence; L-Lactate dehydrogenase; Lactic acid; LC3; MCT4; Medical research; Membrane Potential, Mitochondrial; Metabolism; Metabolites; Microtubule-associated proteins; Microtubule-Associated Proteins - metabolism; Mitochondria; Mitochondria - metabolism; Monocarboxylic Acid Transporters - metabolism; Muscle Proteins - metabolism; optical tissue clearing; p53 Protein; Physiological aspects; reverse Warburg effect; Spheroids; Spheroids, Cellular - metabolism; Stromal cells; Stromal Cells - metabolism; Translocase; Tumor Microenvironment; Tumors; Ubiquitin; Warburg Effect, Oncologic; Germany; optical tissue clearing; MCT4; fibroblasts; reverse Warburg effect; LC3; mitochondria
• ISSN: 2073-4409; 2073-4409
• DOI: 10.3390/cells9081900

Most tumors consume large amounts of glucose. Concepts to explain the mechanisms that mediate the achievement of this metabolic need have proposed a switch of the tumor mass to aerobic glycolysis. Depending on whether primarily tumor or stroma cells undergo such a commutation, the terms 'Warburg effect' or 'reverse Warburg effect' were coined to describe the underlying biological phenomena. However, current in vitro systems relying on 2-D culture, single cell-type spheroids, or basal-membrane extract (BME/Matrigel)-containing 3-D structures do not thoroughly reflect these processes. Here, we aimed to establish a BME/Matrigel-free 3-D microarray cancer model to recapitulate the metabolic interplay between cancer and stromal cells that allows mechanistic analyses and drug testing. Human HT-29 colon cancer and CCD-1137Sk fibroblast cells were used in mono- and co-cultures as 2-D monolayers, spheroids, and in a cell-chip format. Metabolic patterns were studied with immunofluorescence and confocal microscopy. In chip-based co-cultures, HT-29 cells showed facilitated 3-D growth and increased levels of hexokinase-2, TP53-induced glycolysis and apoptosis regulator (TIGAR), lactate dehydrogenase, and: translocase of outer mitochondrial membrane 20 (TOMM20), when compared with HT-29 mono-cultures. Fibroblasts co-cultured with HT-29 cells expressed higher levels of mono-carboxylate transporter 4, hexokinase-2, microtubule-associated proteins 1A/1B light chain 3, and ubiquitin-binding protein p62 than in fibroblast mono-cultures, in both 2-D cultures and chips. Tetramethylrhodamin-methylester (TMRM) live-cell imaging of chip co-cultures revealed a higher mitochondrial potential in cancer cells than in fibroblasts. The findings demonstrate a crosstalk between cancer cells and fibroblasts that affects cellular growth and metabolism. Chip-based 3-D co-cultures of cancer cells and fibroblasts mimicked features of the reverse Warburg effect.