title: ¹H NMR and hyperpolarized ¹³C NMR assays of pyruvate-lactate: a comparative study.
abstract: Pyruvate-lactate exchange is mediated by the enzyme lactate dehydrogenase (LDH) and is central to the altered energy metabolism in cancer cells. The measurement of exchange kinetics using hyperpolarized (13) C NMR has provided a biomarker of response to novel therapeutics. However, the observable signal is restricted to the exchanging hyperpolarized (13) C pools and the endogenous pools of (12) C-labelled metabolites are invisible in these measurements. In this study, we investigated an alternative in vitro (1) H NMR assay, using [3-(13) C]pyruvate, and compared the measured kinetics with a hyperpolarized (13) C NMR assay, using [1-(13) C]pyruvate, under the same conditions in human colorectal carcinoma SW1222 cells. The apparent forward reaction rate constants (kPL ) derived from the two assays showed no significant difference, and both assays had similar reproducibility (kPL  = 0.506 ± 0.054 and kPL  = 0.441 ± 0.090 nmol/s/10(6) cells; mean ± standard deviation; n = 3); (1) H, (13) C assays, respectively). The apparent backward reaction rate constant (kLP ) could only be measured with good reproducibility using the (1) H NMR assay (kLP  = 0.376 ± 0.091 nmol/s/10(6) cells; mean ± standard deviation; n = 3). The (1) H NMR assay has adequate sensitivity to measure real-time pyruvate-lactate exchange kinetics in vitro, offering a complementary and accessible assay of apparent LDH activity.
authors.affiliation: Cancer Research UK and EPRSC Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and Royal Marsden NHS Foundation Trust, 15 Cotswold Road, Sutton, Surrey, SM2 5NG. United Kingdom.
authors.forename: Deborah K
authors.initials: DK
authors.lastname: Hill
authors.affiliation: Cancer Research UK and EPRSC Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and Royal Marsden NHS Foundation Trust, 15 Cotswold Road, Sutton, Surrey, SM2 5NG. United Kingdom.
authors.forename: Yann
authors.initials: Y
authors.lastname: Jamin
authors.affiliation: Cancer Research UK and EPRSC Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and Royal Marsden NHS Foundation Trust, 15 Cotswold Road, Sutton, Surrey, SM2 5NG. United Kingdom.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Orton
authors.affiliation: Cancer Research UK and EPRSC Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and Royal Marsden NHS Foundation Trust, 15 Cotswold Road, Sutton, Surrey, SM2 5NG. United Kingdom.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Tardif
authors.affiliation: Cancer Research UK and EPRSC Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and Royal Marsden NHS Foundation Trust, 15 Cotswold Road, Sutton, Surrey, SM2 5NG. United Kingdom.
authors.forename: Harold G
authors.initials: HG
authors.lastname: Parkes
authors.affiliation: Cancer Research UK and EPRSC Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and Royal Marsden NHS Foundation Trust, 15 Cotswold Road, Sutton, Surrey, SM2 5NG. United Kingdom.
authors.forename: Simon P
authors.initials: SP
authors.lastname: Robinson
authors.affiliation: Cancer Research UK and EPRSC Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and Royal Marsden NHS Foundation Trust, 15 Cotswold Road, Sutton, Surrey, SM2 5NG. United Kingdom.
authors.forename: Martin O
authors.initials: MO
authors.lastname: Leach
authors.affiliation: Cancer Research UK and EPRSC Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and Royal Marsden NHS Foundation Trust, 15 Cotswold Road, Sutton, Surrey, SM2 5NG. United Kingdom.
authors.forename: Yuen-Li
authors.initials: YL
authors.lastname: Chung
authors.affiliation: Cancer Research UK and EPRSC Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and Royal Marsden NHS Foundation Trust, 15 Cotswold Road, Sutton, Surrey, SM2 5NG. United Kingdom.|Division of Imaging Sciences and Biomedical Engineering, Kings College London, St Thomas Hospital, London, SE1 7EH, United Kingdom.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Eykyn
mesh_terms: D002247:Carbon Isotopes; D045744:Cell Line, Tumor; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D011522:Protons; D019289:Pyruvic Acid / Q000378:metabolism*
chemical_list: D002247:Carbon Isotopes; D011522:Protons; D019344:Lactic Acid; D019289:Pyruvic Acid; D007770:L-Lactate Dehydrogenase
keywords: 13C NMR; 1H NMR; cancer; hyperpolarized pyruvate; lactate; lactate dehydrogenase activity