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A high‐throughput imaging platform to characterize extracellular pH in organotypic three‐dimensional in vitro models of liver cancer
Author(s) -
Savic Lynn Jeanette,
Schobert Isabel Theresa,
Hamm Charlie Alexander,
Adam Lucas Christoph,
Hyder Fahmeed,
Coman Daniel
Publication year - 2021
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.4465
Subject(s) - liver cancer , hepatocellular carcinoma , in vitro , extracellular , hepatocyte , chemistry , cancer , magnetic resonance imaging , cancer cell , cell culture , glycolysis , in vivo , microbiology and biotechnology , cancer research , biochemistry , biology , metabolism , medicine , genetics , radiology
Given the extraordinary nature of tumor metabolism in hepatocellular carcinoma and its impact on oncologic treatment response, this study introduces a novel high‐throughput extracellular pH (pH e ) mapping platform using magnetic resonance spectroscopic imaging in a three‐dimensional (3D) in vitro model of liver cancer. pH e mapping was performed using biosensor imaging of redundant deviation in shifts (BIRDS) on 9.4 T and 11.7 T MR scanners for validation purposes. 3D cultures of four liver cancer (HepG2, Huh7, SNU475, VX2) and one hepatocyte (THLE2) cell line were simultaneously analyzed (a) without treatment, (b) supplemented with 4.5 g/L d ‐glucose, and (c) treated with anti‐glycolytic 3‐bromopyruvate (6.25, 25, 50, 75, and 100 μM). The MR results were correlated with immunohistochemistry (GLUT‐1, LAMP‐2) and luminescence‐based viability assays. Statistics included the unpaired t ‐test and ANOVA test. High‐throughput pH e imaging with BIRDS for in vitro 3D liver cancer models proved feasible. Compared with non‐tumorous hepatocytes (pH e = 7.1 ± 0.1), acidic pH e was revealed in liver cancer (VX2, pH e = 6.7 ± 0.1; HuH7, pH e = 6.8 ± 0.1; HepG2, pH e = 6.9 ± 0.1; SNU475, pH e = 6.9 ± 0.1), in agreement with GLUT‐1 upregulation. Glucose addition significantly further decreased pH e in hyperglycolytic cell lines (VX2, HepG2, and Huh7, by 0.28, 0.06, and 0.11, respectively, all p < 0.001), whereas 3‐bromopyruvate normalized tumor pH e in a dose‐dependent manner without affecting viability. In summary, this study introduces a non‐invasive pH e imaging platform for high‐yield screening using a translational 3D liver cancer model, which may help reveal and target mechanisms of therapy resistance and inform personalized treatment of patients with hepatocellular carcinoma.