BIMG-08. DEUTERIUM MAGNETIC RESONANCE SPECTROSCOPY USING 2H-PYRUVATE ALLOWS NON-INVASIVE IN VIVO IMAGING OF TERT EXPRESSION IN BRAIN TUMORS

Abstract Telomere shortening constitutes a natural barrier to uncontrolled proliferation and all tumors must find a mechanism of maintaining telomere length. Most human tumors, including high-grade primary glioblastomas (GBMs) and low-grade oligodendrogliomas (LGOGs) achieve telomere maintenance via reactivation of the expression of telomerase reverse transcriptase (TERT), which is silenced in normal somatic cells. TERT expression is, therefore, a driver of tumor proliferation and, due to this essential role, TERT is also a therapeutic target. However, non-invasive methods of imaging TERT are lacking. The goal of this study was to identify magnetic resonance spectroscopy (MRS)-detectable metabolic biomarkers of TERT expression that will enable non-invasive visualization of tumor burden in LGOGs and GBMs. First, we silenced TERT expression by RNA interference in patient-derived LGOG (SF10417, BT88) and GBM (GS2) models. Our results linked TERT silencing to significant reductions in steady-state levels of NADH in all models. NADH is essential for the conversion of pyruvate to lactate, suggesting that measuring pyruvate flux to lactate could be useful for imaging TERT status. Recently, deuterium (2H)-MRS has emerged as a novel, clinically translatable method of monitoring metabolic fluxes in vivo. However, to date, studies have solely examined 2H-glucose and the use of [U-2H]pyruvate for non-invasive 2H-MRS has not been tested. Following intravenous injection of a bolus of [U-2H]pyruvate, lactate production was higher in mice bearing orthotopic LGOG (BT88 and SF10417) and GBM (GS2) tumor xenografts relative to tumor-free mice, suggesting that [U-2H]pyruvate has the potential to monitor TERT expression in vivo. In summary, our study, for the first time, shows the feasibility and utility of [U-2H]pyruvate for in vivo imaging. Importantly, since 2H-MRS can be implemented on clinical scanners, our results provide a novel, non-invasive method of integrating information regarding a fundamental cancer hallmark, i.e. TERT, into glioma patient management.

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CBMT-41. IMAGING A HALLMARK OF CANCER: HYPERPOLARIZED 13C-MAGNETIC RESONANCE SPECTROSCOPY CAN NON-INVASIVELY MONITOR TERT EXPRESSION IN LOW-GRADE GLIOMAS IN VIVO

Neuro-Oncology ◽

10.1093/neuonc/noz175.163 ◽

2019 ◽

Vol 21 (Supplement_6) ◽

pp. vi42-vi42

Author(s):

Pavithra Viswanath ◽

Georgios Batsios ◽

Anne Marie Gillespie ◽

Russell O Pieper ◽

Sabrina Ronen

Keyword(s):

Lactate Production ◽

Metabolic Imaging ◽

Imaging Biomarkers ◽

Resonance Spectroscopy ◽

Low Grade ◽

Normal Brain ◽

Non Invasive ◽

Glucose Flux ◽

Tert Expression

Abstract Telomerase reverse transcriptase (TERT) expression is a hallmark of cancer, including in primary glioblastomas and low-grade oligodendrogliomas. Since TERT is essential for glioma proliferation and is an attractive therapeutic target, metabolic imaging of TERT status can inform on tumor progression and response to therapy. To that end, the goal of this study was to identify non-invasive, translational, hyperpolarized 13C-magnetic resonance spectroscopy-detectable metabolic imaging biomarkers of TERT in low-grade oligodendrogliomas. Unbiased metabolomic analysis of immortalized normal human astrocytes without (NHAcontrol) and with TERT (NHAtert) indicated that TERT induced unique metabolic reprogramming. Notably, TERT increased NADPH and NADH levels. Glucose flux through the pentose phosphate pathway (PPP) is a major producer of NADPH. Non-invasive imaging of PPP flux using hyperpolarized [U-13C,U-2H]-glucose indicated that production of the PPP metabolite 6-phosphogluconate (6-PG) was elevated in NHAtert cells relative to NHAcontrol. Importantly, hyperpolarized [U-13C,U-2H]-glucose flux to 6-PG clearly differentiated tumor from normal brain in orthotopic NHAtert tumor xenografts. Next, we exploited the observation that TERT expression increased NADH, which is essential for the metabolism of hyperpolarized [1-13C]-alanine to lactate. Lactate production from hyperpolarized [1-13C]-alanine was higher in NHAtert cells relative to NHAcontrol. Importantly, hyperpolarized [1-13C]-alanine imaging in orthotopic NHAtert tumors revealed pronounced differences in lactate production between tumor tissue and normal brain. Mechanistically, TERT increased expression of glucose-6-phosphate dehydrogenase (G6PDH), the rate-limiting enzyme for 6-PG and NADPH production, and of nicotinamide phosphoribosyltransferase (NAMPT), a rate-limiting enzyme for NADH biosynthesis. Silencing TERT reversed G6PDH and NAMPT expression and normalized hyperpolarized [U-13C,U-2H]-glucose and [1-13C]-alanine metabolism, validating our imaging biomarkers. Finally, hyperpolarized [U-13C,U-2H]-glucose and [1-13C]-alanine could monitor TERT status in the clinically relevant, patient-derived BT54 oligodendroglioma model. In summary, we demonstrate, for the first time, non-invasive in vivo imaging of TERT status in gliomas that can enable longitudinal analysis of tumor burden and treatment response in the clinic.

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NIMG-51. DEUTERIUM METABOLIC IMAGING OF BRAIN TUMOR IMMORTALITY USING 2H-PYRUVATE

Neuro-Oncology ◽

10.1093/neuonc/noab196.549 ◽

2021 ◽

Vol 23 (Supplement_6) ◽

pp. vi140-vi141

Author(s):

Georgios Batsios ◽

Céline Taglang ◽

Meryssa Tran ◽

Anne Marie Gillespie ◽

Sabrina Ronen ◽

...

Keyword(s):

Brain Tumor ◽

Lactate Production ◽

Response To Therapy ◽

Telomere Maintenance ◽

Metabolic Imaging ◽

Resonance Spectroscopy ◽

Low Grade ◽

Tumor Proliferation ◽

Non Invasive ◽

Tert Expression

Abstract Telomere maintenance is essential for tumor immortality and sustained tumor proliferation. Most tumors, including high-grade glioblastomas and low-grade oligodendrogliomas achieve telomere maintenance via reactivation of the expression of telomerase reverse transcriptase (TERT), which is silenced in normal somatic cells. Due to this essential role, TERT is a therapeutic target and TERT inhibitors such as 6-thio-2’-deoxyguanosine are in clinical trials. Non-invasive methods of imaging TERT, therefore, have the potential to provide a readout of tumor proliferation and response to therapy. We previously showed that TERT expression is associated with elevated levels of NADH in gliomas. Since NADH is essential for the conversion of pyruvate to lactate, measuring pyruvate flux to lactate could be useful for imaging TERT expression. In this context, deuterium magnetic resonance spectroscopy (2H-MRS) recently emerged as a novel, clinically translatable method of monitoring metabolic fluxes. The goal of this study was to assess the potential of [U-2H]pyruvate for non-invasive imaging of TERT status in gliomas. Following intravenous injection of [U-2H]pyruvate, lactate production was significantly higher in mice bearing orthotopic oligodendroglioma (SF10417, BT88) or glioblastoma (GBM1, GBM6) tumors relative to tumor-free controls. 2D chemical shift imaging showed localization of lactate production to tumor vs. contralateral normal brain. Importantly, following treatment of mice bearing orthotopic GBM6 or BT88 tumors with the TERT inhibitor 6-thio-2’-deoxyguanosine, lactate production from [U-2H]pyruvate was significantly reduced at early timepoints when alterations in tumor volume could not be detected by anatomical imaging, pointing to the ability of [U-2H]pyruvate to report on pseudoprogression. Collectively, we have, for the first time, demonstrated the utility of [U-2H]pyruvate for metabolic imaging of brain tumor burden and treatment response in vivo. Importantly, since 2H-MRS can be implemented on clinical scanners, our results provide a novel, non-invasive method of integrating information regarding a fundamental tumor hallmark, i.e. TERT, into glioma patient management.

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Imaging toxin-induced neuroinflammation in mice using hyperpolarized13C magnetic resonance spectroscopy

10.1101/605568 ◽

2019 ◽

Author(s):

Lydia M Le Page ◽

Caroline Guglielmetti ◽

Chloé Najac ◽

Brice Tiret ◽

Myriam M Chaumeil

Keyword(s):

Magnetic Resonance ◽

Magnetic Resonance Spectroscopy ◽

Mouse Brain ◽

Lactate Production ◽

Contralateral Side ◽

Resonance Spectroscopy ◽

Activated Microglia ◽

Non Invasive ◽

Induced Changes

AbstractLipopolysaccharide (LPS) is a commonly used agent for induction of neuroinflammation in preclinical studies. Upon injection, LPS causes activation of microglia and astrocytes, whose metabolism alters to favor glycolysis. Assessingin vivoneuroinflammation and its modulation following therapy remains challenging, and new non-invasive methods allowing for longitudinal monitoring would be greatly valuable. Hyperpolarized (HP)13C magnetic resonance spectroscopy (MRS) is a promising technique for assessingin vivometabolism. In addition to applications in oncology, the most commonly used probe of [1-13C] pyruvate has shown potential in assessing neuroinflammation-linked metabolism in mouse models of multiple sclerosis and traumatic brain injury. Here, we wished to investigate LPS-induced neuroinflammatory changes using HP [1-13C] pyruvate and HP13C urea.2D chemical shift imaging following simultaneous intravenous injection of HP [1-13C] pyruvate and HP13C urea was performed at baseline (day 0), day 3 and day 7 post intracranial injection of LPS (n=6) or saline (n=5). Immunofluorescence (IF) analyses were performed for Iba1 (resting and activated microglia/macrophages), GFAP (resting and reactive astrocytes) and CD68 (activated microglia/macrophages).A significant increase in HP [1-13C] lactate production was observed in the injected (ipsilateral) side at 3 and 7 days of the LPS-treated mouse brain, but not in either the contralateral side or saline-injected animals. HP13C lactate/pyruvate ratio, without and with normalization to urea, was also significantly increased in the ipsilateral LPS-injected brain at 7 days compared to baseline. IF analyses showed a significant increase in CD68 and GFAP at 3 days, followed by increased numbers of Iba1 and GFAP positive cells at 7 days post-LPS injection.In conclusion, we can detect LPS-induced changes in the mouse brain using HP13C MRS, in alignment with increased numbers of microglia/macrophages and astrocytes. This study demonstrates that HP13C spectroscopy holds much potential for providing non-invasive information on neuroinflammation.

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BIOM-10. PRECLINICAL PLATFORM FOR THE IDENTIFICATION OF DEUTERIUM MAGNETIC RESONANCE SPECTROSCOPY-BASED BIOMARKERS OF BRAIN TUMOR METABOLISM

Neuro-Oncology ◽

10.1093/neuonc/noab196.041 ◽

2021 ◽

Vol 23 (Supplement_6) ◽

pp. vi12-vi12

Author(s):

Georgios Batsios ◽

Meryssa Tran ◽

Céline Taglang ◽

Anne Marie Gillespie ◽

Sabrina Ronen ◽

...

Keyword(s):

Brain Tumor ◽

Magnetic Resonance ◽

Magnetic Resonance Spectroscopy ◽

Brain Tumors ◽

Treatment Response ◽

Lactate Production ◽

Cell Suspensions ◽

Response To Therapy ◽

Resonance Spectroscopy

Abstract Metabolic reprogramming is a fundamental hallmark of cancer, which can be exploited for non-invasive tumor imaging. Deuterium magnetic resonance spectroscopy (2H-MRS) recently emerged as a novel, translational method of interrogating flux from 2H-labeled substrates to metabolic products. However, to date, preclinical studies have been performed in vivo, an endeavor which suffers from low-throughput and potential wastage of animal life, especially when considering studies of treatment response. Developing in vitro assays for monitoring metabolism of 2H-labeled substrates will enhance throughput, lead to the rapid evaluation of new 2H-based probes and enable identification of treatment response biomarkers, thereby allowing the best 2H-based probes to be translated for further in vivo assessment. The goal of this study was to develop a preclinical cell-based platform for quantifying metabolism of 2H-labeled probes in brain tumor models. Since the Warburg effect, which is characterized by elevated glycolytic production of lactate, is a metabolic phenotype of cancer, including brain tumors, we examined metabolism of 2H-glucose or 2H-pyruvate in patient-derived glioblastoma (GBM6) and oligodendroglioma (BT88) cells and compared to normal human astrocytes (NHACONTROL). Following incubation in media containing [6,6’-2H]glucose or [U-2H]pyruvate, 2H-MR spectra obtained from live cell suspensions showed elevated 2H-lactate production in GBM6 and BT88 cells relative to NHACONTROL. Importantly, 2H-lactate production from [6,6’-2H]glucose or from [U-2H]pyruvate was reduced in GBM6 or BT88 cells subjected to irradiation and temozolomide, which is standard of care for glioma patients, pointing to the utility of this method for detecting response to therapy. Collectively, we have, for the first time, demonstrated the ability to quantify metabolism of 2H-MRS probes in live cell suspensions and validated the utility of our assay for differentiating tumor from normal cells and assessing response to therapy. Our studies will expedite the identification of novel 2H-MRS probes for imaging brain tumors and potentially other types of cancer.

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Introduction to in vivo31P magnetic resonance spectroscopy of (human) skeletal muscle

Proceedings of The Nutrition Society ◽

10.1017/s0029665199001160 ◽

1999 ◽

Vol 58 (4) ◽

pp. 861-870 ◽

Cited By ~ 32

Author(s):

A. Heerschap ◽

C. Houtman ◽

H. J. A. in 't Zandt ◽

A. J. van den Bergh ◽

B. Wieringa

Keyword(s):

Skeletal Muscle ◽

Magnetic Resonance ◽

Magnetic Resonance Spectroscopy ◽

Current Status ◽

Resonance Spectroscopy ◽

Biochemical Processes ◽

Non Invasive ◽

Introductory Overview ◽

Muscle Biochemistry

31P magnetic resonance spectroscopy (MRS) offers a unique non-invasive window on energy metabolism in skeletal muscle, with possibilities for longitudinal studies and of obtaining important bioenergetic data continuously and with sufficient time resolution during muscle exercise. The present paper provides an introductory overview of the current status of in vivo31P MRS of skeletal muscle, focusing on human applications, but with some illustrative examples from studies on transgenic mice. Topics which are described in the present paper are the information content of the 31P magnetic resonance spectrum of skeletal muscle, some practical issues in the performance of this MRS methodology, related muscle biochemistry and the validity of interpreting results in terms of biochemical processes, the possibility of investigating reaction kinetics in vivo and some indications for fibre-type heterogeneity as seen in spectra obtained during exercise.

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Non-Invasive Prediction of IDH Mutation in Patients with Glioma WHO II/III/IV Based on F-18-FET PET-Guided In Vivo 1H-Magnetic Resonance Spectroscopy and Machine Learning

Cancers ◽

10.3390/cancers12113406 ◽

2020 ◽

Vol 12 (11) ◽

pp. 3406

Author(s):

Elisabeth Bumes ◽

Fro-Philip Wirtz ◽

Claudia Fellner ◽

Jirka Grosse ◽

Dirk Hellwig ◽

...

Keyword(s):

Machine Learning ◽

Magnetic Resonance ◽

Magnetic Resonance Spectroscopy ◽

Support Vector ◽

Resonance Spectroscopy ◽

Idh Mutation ◽

1H Mrs ◽

1H Magnetic Resonance Spectroscopy ◽

Non Invasive

Isocitrate dehydrogenase (IDH)-1 mutation is an important prognostic factor and a potential therapeutic target in glioma. Immunohistological and molecular diagnosis of IDH mutation status is invasive. To avoid tumor biopsy, dedicated spectroscopic techniques have been proposed to detect D-2-hydroxyglutarate (2-HG), the main metabolite of IDH, directly in vivo. However, these methods are technically challenging and not broadly available. Therefore, we explored the use of machine learning for the non-invasive, inexpensive and fast diagnosis of IDH status in standard 1H-magnetic resonance spectroscopy (1H-MRS). To this end, 30 of 34 consecutive patients with known or suspected glioma WHO grade II-IV were subjected to metabolic positron emission tomography (PET) imaging with O-(2-18F-fluoroethyl)-L-tyrosine (18F-FET) for optimized voxel placement in 1H-MRS. Routine 1H-magnetic resonance (1H-MR) spectra of tumor and contralateral healthy brain regions were acquired on a 3 Tesla magnetic resonance (3T-MR) scanner, prior to surgical tumor resection and molecular analysis of IDH status. Since 2-HG spectral signals were too overlapped for reliable discrimination of IDH mutated (IDHmut) and IDH wild-type (IDHwt) glioma, we used a nested cross-validation approach, whereby we trained a linear support vector machine (SVM) on the complete spectral information of the 1H-MRS data to predict IDH status. Using this approach, we predicted IDH status with an accuracy of 88.2%, a sensitivity of 95.5% (95% CI, 77.2–99.9%) and a specificity of 75.0% (95% CI, 42.9–94.5%), respectively. The area under the curve (AUC) amounted to 0.83. Subsequent ex vivo 1H-nuclear magnetic resonance (1H-NMR) measurements performed on metabolite extracts of resected tumor material (eight specimens) revealed myo-inositol (M-ins) and glycine (Gly) to be the major discriminators of IDH status. We conclude that our approach allows a reliable, non-invasive, fast and cost-effective prediction of IDH status in a standard clinical setting.

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Magnetic Resonance Spectroscopy and its Applications in Psychiatry

Australian & New Zealand Journal of Psychiatry ◽

10.1046/j.1440-1614.2002.00992.x ◽

2002 ◽

Vol 36 (1) ◽

pp. 31-43 ◽

Cited By ~ 58

Author(s):

Gin S. Malhi ◽

Michael Valenzuela ◽

Wei Wen ◽

Perminder Sachdev

Keyword(s):

Magnetic Resonance ◽

Magnetic Resonance Spectroscopy ◽

Brain Regions ◽

Response To Treatment ◽

Resonance Spectroscopy ◽

Biochemical Basis ◽

Non Invasive ◽

Investigative Technique ◽

Neurochemical Changes

Objective: This paper briefly describes neuroimaging using magnetic resonance spectroscopy (MRS) and provides a systematic review of its application to psychiatric disorders. Method: A literature review ( Index Medicus/ Medline) was carried out, as well as a review of other relevant papers and data known to the authors. Results: Magnetic resonance spectroscopy is a complex and sophisticated neuroimaging technique that allows reliable and reproducible quantification of brain neurochemistry provided its limitations are respected. In some branches of medicine it is already used clinically, for instance, to diagnose tumours and in psychiatry its applications are gradually extending beyond research. Neurochemical changes have been found in a variety of brain regions in dementia, schizophrenia and affective disorders and promising discoveries have also been made in anxiety disorders. Conclusions: Magnetic resonance spectroscopy is a non-invasive investigative technique that has provided useful insights into the biochemical basis of many neuropsychiatric disorders. It allows direct measurement, in vivo, of medication levels within the brain and has made it possible to track the neurochemical changes that occur as a consequence of disease and ageing or in response to treatment. It is an extremely useful advance in neuroimaging technology and one that will undoubtedly have many clinical uses in the near future.

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In vivo imaging of glia activation using1H-magnetic resonance spectroscopy to detect putative biomarkers of tissue epileptogenicity

Epilepsia ◽

10.1111/j.1528-1167.2012.03685.x ◽

2012 ◽

Vol 53 (11) ◽

pp. 1907-1916 ◽

Cited By ~ 54

Author(s):

Marta Filibian ◽

Angelisa Frasca ◽

Daniela Maggioni ◽

Edoardo Micotti ◽

Annamaria Vezzani ◽

...

Keyword(s):

Magnetic Resonance ◽

Magnetic Resonance Spectroscopy ◽

In Vivo Imaging ◽

Resonance Spectroscopy ◽

Glia Activation

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Hyperpolarized 13C pyruvate magnetic resonance spectroscopy for in vivo metabolic phenotyping of rat HCC

Scientific Reports ◽

10.1038/s41598-020-80952-4 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Elisabeth Bliemsrieder ◽

Georgios Kaissis ◽

Martin Grashei ◽

Geoffrey Topping ◽

Jennifer Altomonte ◽

...

Keyword(s):

Magnetic Resonance ◽

Magnetic Resonance Spectroscopy ◽

Tumor Tissue ◽

Ex Vivo ◽

Kinetic Modelling ◽

Lactate Production ◽

Resonance Spectroscopy ◽

Primary Tumors ◽

Conversion Rates

AbstractThe in vivo assessment of tissue metabolism represents a novel strategy for the evaluation of oncologic disease. Hepatocellular carcinoma (HCC) is a high-prevalence, high-mortality tumor entity often discovered at a late stage. Recent evidence indicates that survival differences depend on metabolic alterations in tumor tissue, with particular focus on glucose metabolism and lactate production. Here, we present an in vivo imaging technique for metabolic tumor phenotyping in rat models of HCC. Endogenous HCC was induced in Wistar rats by oral diethyl-nitrosamine administration. Peak lactate-to-alanine signal ratios (L/A) were assessed with hyperpolarized magnetic resonance spectroscopic imaging (HPMRSI) after [1-13C]pyruvate injection. Cell lines were derived from a subset of primary tumors, re-implanted in nude rats, and assessed in vivo with dynamic hyperpolarized magnetic resonance spectroscopy (HPMRS) after [1-13C]pyruvate injection and kinetic modelling of pyruvate metabolism, taking into account systemic lactate production and recirculation. For ex vivo validation, enzyme activity and metabolite concentrations were spectroscopically quantified in cell and tumor tissue extracts. Mean peak L/A was higher in endogenous HCC compared to non-tumorous tissue. Dynamic HPMRS revealed higher pyruvate-to-lactate conversion rates (kpl) and lactate signal in subcutaneous tumors derived from high L/A tumor cells, consistent with ex vivo measurements of higher lactate dehydrogenase (LDH) levels in these cells. In conclusion, HPMRS and HPMRSI reveal distinct tumor phenotypes corresponding to differences in glycolytic metabolism in HCC tumor tissue.

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