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Matsuo M, Kawai T, Kishimoto S, Saito K, Munasinghe J, Devasahayam N, Mitchell JB, Krishna MC. Co-imaging of the tumor oxygenation and metabolism using electron paramagnetic resonance imaging and 13-C hyperpolarized magnetic resonance imaging before and after irradiation. Oncotarget 2018; 9:25089-25100. [PMID: 29861855 PMCID: PMC5982751 DOI: 10.18632/oncotarget.25317] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 04/02/2018] [Indexed: 01/18/2023] Open
Abstract
To examine the relationship between local oxygen partial pressure and energy metabolism in the tumor, electron paramagnetic resonance imaging (EPRI) and magnetic resonance imaging (MRI) with hyperpolarized [1-13C] pyruvate were performed. SCCVII and HT29 solid tumors implanted in the mouse leg were imaged by EPRI using OX063, a paramagnetic probe and 13C-MRI using hyperpolarized [1-13C] pyruvate. Local partial oxygen pressure and pyruvate metabolism in the two tumor implants were examined. The effect of a single dose of 5-Gy irradiation on the pO2 and metabolism was also investigated by sequential imaging of EPRI and 13C-MRI in HT29 tumors. A phantom study using tubes filled with different concentration of [1-13C] pyruvate, [1-13C] lactate, and OX063 at different levels of oxygen confirmed the validity of this sequential imaging of EPRI and hyperpolarized 13C-MRI. In vivo studies revealed SCCVII tumor had a significantly larger hypoxic fraction (pO2 < 8 mmHg) compared to HT29 tumor. The flux of pyruvate-to-lactate conversion was also higher in SCCVII than HT29. The lactate-to-pyruvate ratio in hypoxic regions (pO2 < 8 mmHg) 24 hours after 5-Gy irradiation was significantly higher than those without irradiation (0.76 vs. 0.36) in HT29 tumor. The in vitro study showed an increase in extracellular acidification rate after irradiation. In conclusion, co-imaging of pO2 and pyruvate-to-lactate conversion kinetics successfully showed the local metabolic changes especially in hypoxic area induced by radiation therapy.
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Affiliation(s)
- Masayuki Matsuo
- Radiation Biology Branch, Center for Cancer research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.,Department of Radiology, Gifu University Graduate School of Medicine, Gifu City, Japan
| | - Tatsuya Kawai
- Radiation Oncology Branch, Center for Cancer research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Shun Kishimoto
- Radiation Biology Branch, Center for Cancer research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Keita Saito
- Radiation Biology Branch, Center for Cancer research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jeeva Munasinghe
- MRI Research Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Nallathamby Devasahayam
- Radiation Biology Branch, Center for Cancer research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - James B Mitchell
- Radiation Biology Branch, Center for Cancer research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Murali C Krishna
- Radiation Biology Branch, Center for Cancer research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
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