title: Real-time measurement of hyperpolarized lactate production and efflux as a biomarker of tumor aggressiveness in an MR compatible 3D cell culture bioreactor.
abstract: We have developed a 3D cell/tissue culture bioreactor compatible with hyperpolarized (HP) (13)C MR and interrogated HP [1-(13)C]lactate production and efflux in human renal cell carcinoma (RCC) cells. This platform is capable of resolving intracellular and extracellular HP lactate pools, allowing the kinetic measurement of lactate production and efflux in the context of cancer aggressiveness and response to therapy. HP (13)C MR studies were performed on three immortalized human renal cell lines: HK2, a normal renal proximal tubule cell line from which a majority of RCCs arise, UMRC6, a cell line derived from a localized RCC, and UOK262, an aggressive and metastatic RCC. The intra- (Lacin ) and extracellular (Lacex ) HP lactate signals were robustly resolved in dynamic (13)C spectra of the cell lines due to a very small but reproducible chemical shift difference (0.031 ± 0.0005 ppm). Following HP [1-(13)C]pyruvate delivery, the ratio of HP Lacin /Lacex was significantly lower for UOK262 cells compared with both UMRC6 and HK2 cells due to a significant (p < 0.05) increase in the Lacex pool size. Lacin /Lacex correlated with the MCT4 mRNA expression of the cell lines, and inhibition of MCT4 transport using DIDS resulted in a significant reduction in the HP Lacex pool size. The extension of these studies to living patient-derived RCC tissue slices using HP [1,2-(13)C2]pyruvate demonstrated a similarly split lactate doublet with a high Lacex pool fraction; in contrast, only a single NMR resonance is noted for HP [5-(13)C]glutamate, consistent with intracellular localization. These studies support the importance of lactate efflux as a biomarker of cancer aggressiveness and metastatic potential, and the utility of the MR compatible 3D cell/tissue culture bioreactor to study not only cellular metabolism but also transport. Additionally, this platform offers a sophisticated way to follow therapeutic interventions and screen novel therapies that target lactate export.
authors.affiliation: Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA.
authors.forename: Renuka
authors.initials: R
authors.lastname: Sriram
authors.affiliation: Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Van Criekinge
authors.affiliation: Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Ailin
authors.initials: A
authors.lastname: Hansen
authors.affiliation: Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA.
authors.forename: Zhen J
authors.initials: ZJ
authors.lastname: Wang
authors.affiliation: Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA.
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Vigneron
authors.affiliation: Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA.
authors.forename: David M
authors.initials: DM
authors.lastname: Wilson
authors.affiliation: Radiology and Molecular Pharmacology and Chemistry Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: Kayvan R
authors.initials: KR
authors.lastname: Keshari
authors.affiliation: Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA.
authors.forename: John
authors.initials: J
authors.lastname: Kurhanewicz
mesh_terms: D014408:Biomarkers, Tumor; D019149:Bioreactors; D002292:Carcinoma, Renal Cell / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007668:Kidney / Q000378:metabolism; D007680:Kidney Neoplasms / Q000378:metabolism* / Q000473:pathology; D019344:Lactic Acid / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*
chemical_list: D014408:Biomarkers, Tumor; D019344:Lactic Acid
keywords: aerobic glycolysis; cancer aggressiveness; dynamic nuclear polarization (DNP); hyperpolarized 13C magnetic resonance (HP 13C MR); lactate; lactate efflux; pyruvate; renal cell carcinoma (RCC)