Early gene therapy–induced apoptotic response in BT4C gliomas by magnetic resonance relaxation contrast T1 in the rotating frame

Hakumäki, Juhana M.; Gröhn, Olli; Tyynelä, Kristiina; Valonen, Piia; Ylä‐Herttuala, Seppo; Kauppinen, Risto A.

doi:10.1038/sj.cgt.7700450

Cited by 59 publications

(63 citation statements)

References 36 publications

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“…The cell density was 183 Ϯ 13, 154 Ϯ 14, 109 Ϯ 4, and 71 Ϯ 2 ϫ 10 3 cell/mm 3 in days 2, 4, 6, and 8 of treated tumors, respectively; day 6 and 8 values were significantly less than that at day 0 (p Ͻ 0.01). These observations confirmed that gene therapy had induced PCD (14,22), resulting in severe cell loss in the gliomas.…”

Section: Resultssupporting

confidence: 77%

“…In some animals, 1 H NMR spectra were also acquired from the same voxel using the localization by adiabatic selective refocusing (LASER) method as described previously (21) (TR, 8.8 s; TE, 32 ms; SW, 2.5 kHz; 13,000 data points). Metabolite concentrations were quantified from STEAM spectra using non-suppressed water peak as a reference (0.787 kg/kg of fresh untreated BT4C tumor tissue) (22), corrected for T 1 saturation effects because of water accumulation during PCD, using the T 1 values recently reported (22).…”

Section: Methodsmentioning

confidence: 99%

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Metabolite Changes in BT4C Rat Gliomas Undergoing Ganciclovir-Thymidine Kinase Gene Therapy-induced Programmed Cell Death as Studied by 1H NMR Spectroscopy in Vivo, ex Vivo, and in Vitro

Lehtimäki

Valonen

Griffin

et al. 2003

Journal of Biological Chemistry

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Programmed cell death was induced by HSV-tk gene therapy in rat BT4C glioma cells, and metabolite changes associated with cell damage were monitored in vivo by 1 H NMR spectroscopy and ex vivo by high resolution magic angle spinning (HRMAS) 1 H NMR, and in vitro in perchloric acid extracts of tumors. Metabolite concentrations, as quantified in vivo using water as an internal reference and in vitro in extracts, were correlated with cell density. The results showed that both in vivo and in vitro glycine and creatine concentrations followed volume-averaged cell density, whereas that of total choline-containing compounds was unaffected by a cell loss approaching 60%. Meanwhile, both saturated and unsaturated 1 H NMR visible lipids increased. HR-MAS 1 H NMR spectroscopy of the tumor samples at 14.1 tesla demonstrated the presence of nucleotide peaks from adenosine and uridine nucleotides in glioma samples ex vivo. The assignment of a doublet at 7.95 ppm to UDP was confirmed by spiking experiments of tumor extracts in conjunction with 1 H and 31 P NMR spectroscopy. HRMAS also resolved the choline-containing peak at 3.2 ppm in vivo into resonances from choline (3.20 ppm), phosphocholine (3.22 ppm), glycerophosphocholine (3.24 ppm), and taurine (3.26 ppm). These resonances were uncorrelated with temporal progression through programmed cell death. Our results show that 1 H NMR-detected lipids and some of the small molecular weight metabolites respond to gene therapy. However, the choline-containing compounds are unaffected by severe decline in cell density. The latter observation supports the idea that triacylglycerols, rather than membrane phospholipids, are the key components of 1 H NMR visible lipids, and it also casts doubt on the validity of resonance of choline-containing compounds as a diagnostic marker of programmed cell death in vivo. Programmed cell death (PCD)1 involves a cascade of biochemical processes in an ATP-dependent manner, and the process is associated with substantial morphological alterations in the cell interior before phagocytosis (1-3). Recent evidence from cell culture studies points to a number of characteristic metabolic perturbations appearing in the early phase of PCD. These include affections of intermediary metabolism, such as accumulation of glycolytic intermediates fructose 1,6-bisphosphate, dihydroxy acetone phosphate, and glycerol-3-phosphate because of inhibition of glyceraldehyde-3-phosphate dehydrogenase (4), retention of CDP-choline (5) as a result of inhibition of CDP-choline:1,2-diacylglycerol choline phosphotransferase (6), and collapse of NAD(H) levels (5). The severe decline in NAD(H), leading to inhibition of glycolysis, may result from activation of poly(ADP-ribose) polymerase in apoptotic cells (5). Inhibition of CDP-choline:1,2-diacylglycerol choline phospotransferase leads to cessation of phosphatidylcholine biosynthesis (6), and it has been proposed that this might be one of the mechanisms explaining accumulation of 1 H NMR lipids into cells undergoing apoptosis (7,8). I...

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Section: Resultssupporting

confidence: 77%

Section: Methodsmentioning

confidence: 99%

Metabolite Changes in BT4C Rat Gliomas Undergoing Ganciclovir-Thymidine Kinase Gene Therapy-induced Programmed Cell Death as Studied by 1H NMR Spectroscopy in Vivo, ex Vivo, and in Vitro

Lehtimäki

Valonen

Griffin

et al. 2003

Journal of Biological Chemistry

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“…Proton magnetic resonance spectroscopy is emerging as a highly useful tool for this purpose (Hakumaki et al, 2002;Kauppinen, 2002). In the present work, we evaluated the relevance of MLs and Chocontaining compounds detected in vivo by 1 H MRS in a xenograft model of human neuroblastoma.…”

Section: Discussionmentioning

confidence: 99%

Noninvasive estimation of tumour viability in a xenograft model of human neuroblastoma with proton magnetic resonance spectroscopy (1H MRS)

et al. 2003

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The aim of the study was to evaluate proton magnetic resonance spectroscopy ( 1 H MRS) for noninvasive biological characterisation of neuroblastoma xenografts in vivo. For designing the experiments, human neuroblastoma xenografts growing subcutaneously in nude rats were analysed in vivo with 1 H MRS and magnetic resonance imaging at 4.7 T. The effects of spontaneous tumour growth and antiangiogenesis treatment, respectively, on spectral characteristics were evaluated. The spectroscopic findings were compared to tumour morphology, proliferation and viable tumour tissue fraction. The results showed that signals from choline (Cho)-containing compounds and mobile lipids (MLs) dominated the spectra. The individual ML/Cho ratios for both treated and untreated tumours were positively correlated with tumour volume (Po0.05). There was an inverse correlation between the ML/Cho ratio and the viable tumour fraction (r ¼ À0.86, Po0.001). Higher ML/Cho ratios concomitant with pronounced histological changes were seen in spectra from tumours treated with the antiangiogenic drug TNP-470, compared to untreated control tumours (Po0.05). In conclusion, the ML/Cho ratio obtained in vivo by 1 H MRS enabled accurate assessment of the viable tumour fraction in a human neuroblastoma xenograft model. 1 H MRS also revealed early metabolic effects of antiangiogenesis treatment. 1 H MRS could prove useful as a tool to monitor experimental therapy in preclinical models of neuroblastoma, and possibly also in children.

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“…Clinical applications of ULFMRI of brain might also include monitoring the progression of Alzheimer's and Parkinson diseases, based on changes in T 1ρ contrast previously demonstrated at high field (56-58). Finally, high-field T 1ρ contrast imaging has also been suggested as a potential biomarker for gene therapy of tumors (59,60). Although ULFMRI still requires significant development to achieve clinically useful spatial resolution with an acceptable imaging time, it may ultimately find novel clinical applications that complement those already established with HFMRI.…”

Section: Discussion and Outlookmentioning

confidence: 99%

MRI of the human brain at 130 microtesla

Inglis

Buckenmaier

SanGiorgio

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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We present in vivo images of the human brain acquired with an ultralow field MRI (ULFMRI) system operating at a magnetic field B 0 ∼ 130 μT. The system features prepolarization of the proton spins at B p ∼ 80 mT and detection of the NMR signals with a superconducting, second-derivative gradiometer inductively coupled to a superconducting quantum interference device (SQUID). We report measurements of the longitudinal relaxation time T 1 of brain tissue, blood, and scalp fat at B 0 and B p , and cerebrospinal fluid at B 0 . We use these T 1 values to construct inversion recovery sequences that we combine with Carr-Purcell-Meiboom-Gill echo trains to obtain images in which one species can be nulled and another species emphasized. In particular, we show an image in which only blood is visible. Such techniques greatly enhance the already high intrinsic T 1 contrast obtainable at ULF. We further present 2D images of T 1 and the transverse relaxation time T 2 of the brain and show that, as expected at ULF, they exhibit similar contrast. Applications of brain ULFMRI include integration with systems for magnetoencephalography. More generally, these techniques may be applicable, for example, to the imaging of tumors without the need for a contrast agent and to modalities recently demonstrated with T 1ρ contrast imaging (T 1 in the rotating frame) at fields of 1.5 T and above. . 3D magnetic field gradients specify a unique magnetic field and thus an NMR frequency or phase in each voxel of the subject, so that with appropriate signal decoding one can acquire a 3D image (4).Clinical MRI systems with B 0 = 1:5 T achieve a spatial resolution of typically 1 mm; 3-T systems are becoming increasingly widespread in clinical practice (5), offering a higher signal-tonoise ratio (SNR) and thus higher spatial resolution. Nonetheless, there is ongoing interest in less expensive MRI systems operating at lower fields. Commercially available 0.2-to 0.5-T systems based on permanent magnets offer both lower cost and wider patient aperture than their higher field counterparts, at the expense of spatial resolution. At the still lower field of 0.03 T maintained by a room temperature solenoid, Connolly and coworkers (6, 7) obtained clinically useful SNR and spatial resolution by prepolarizing the protons in a field B p of 0.3 T. Prepolarization (8) enhances the magnetization of the proton ensemble over that produced by the lower precession field; after the polarizing field is removed, the higher magnetization produces a correspondingly larger signal during its precession in B 0 . Using the same method, Stepisnik et al. (9) obtained MR images in the Earth's magnetic field (∼ 50 μT).In recent years there has been increasing interest (10-36) in NMR and MRI at fields ranging from a few nanotesla to the order of 100 μT. The enormous reduction in the detected signal amplitude compared with the high field value is overcome partly by using prepolarization and partly by detecting the signal with an untuned superconducting input circuit inductively coupl...

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Early gene therapy–induced apoptotic response in BT4C gliomas by magnetic resonance relaxation contrast T1 in the rotating frame

Cited by 59 publications

References 36 publications

Metabolite Changes in BT4C Rat Gliomas Undergoing Ganciclovir-Thymidine Kinase Gene Therapy-induced Programmed Cell Death as Studied by 1H NMR Spectroscopy in Vivo, ex Vivo, and in Vitro

Metabolite Changes in BT4C Rat Gliomas Undergoing Ganciclovir-Thymidine Kinase Gene Therapy-induced Programmed Cell Death as Studied by 1H NMR Spectroscopy in Vivo, ex Vivo, and in Vitro

Noninvasive estimation of tumour viability in a xenograft model of human neuroblastoma with proton magnetic resonance spectroscopy (1H MRS)

MRI of the human brain at 130 microtesla

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