¹H NMR detects different metabolic profiles in glioblastoma stem‐like cells

Abstract

The metabolic profiles of glioblastoma stem-like cells (GSCs) growing in neurospheres were examined by (1)H NMR spectroscopy. Spectra of two GSC lines, labelled 1 and 83, from tumours close to the subventricular zone of the temporal lobe were studied in detail and compared with those of neural stem/progenitor cells from the adult olfactory bulb (OB-NPCs) and of the T98G glioblastoma cell line. In both GSCs, signals from myoinositol (Myo-I), UDP-hexosamines (UDP-Hex) and glycine indicated an astrocyte/glioma metabolism. For line 1, the presence of signals from N-acetyl aspartate, GABA and creatine pointed to a neuronal fingerprint. These metabolites were almost absent from line 83 spectra, whereas lipid signals, absent from normal neural lineages, were intense in line 83 spectra and remained low in those of line 1, irrespective of apoptotic fate. Spectra of OB-NPC cells displayed strong similarities with those from line 1, with low lipid signals and clearly detectable neuronal signals. In contrast, the spectral profile of line 83 was more similar to that of T98G, displaying high lipids and nearly complete absence of the neuronal markers. A mixed neural-astrocyte metabolic phenotype with a strong neuronal fingerprint was therefore found in line 1, while an astrocytic/glioma-like metabolism prevailed in line 83. We found a signal assigned to the amide proton of N-acetyl galactosamine in GSC lines and in OB-NPC spectra, whereas it was absent from those of T98G cells. This signal may be related to a stem-cell-specific protein glycosylation pattern and is therefore suggested as a marker of cell multipotency. Other GSC lines from patients with different clinical outcomes were then examined. Unsupervised analysis of spectral data from 13 lines yielded two clusters, with six lines resembling spectral features of line 1 and seven resembling those of line 83, suggesting that distinct metabolic phenotypes may be present in GSC lines.

RYK promotes the stemness of glioblastoma cells via the WNT/β-catenin pathway

“…We next investigated the effect of silencing RYK on two different patient-derived GSC lines (patients #1 and #83) [19]. The ability of GSCs to form neurospheres in vitro was drastically impaired by knocking down RYK expression with a specific siRNA (Figure 2A); moreover, GSC markers were decreased (Figure 2B).…”

“…GBM tissue specimens were obtained from adult patients undergoing craniotomy at the Institute of Neurosurgery, School of Medicine, Università Cattolica, Rome, Italy, as previously described [19, 26, 27]. Informed consent was obtained from patients before surgery.…”

Evaluating Acetate Metabolism for Imaging and Targeting in Multiple Myeloma

“…1D) in MMC extracts consistent with cellular acetate uptake (26). Importantly, we found evidence of intracellular acetate metabolism through 13 C-labeling of a number of other compounds, mostly in peaks consistent with -CH 2 - in groups at chemical shifts of 2.07 ppm (peak #3, 3-glutamate) (26), 2.35–2.37 ppm (peak #4, 4-glutamate)(26), and 2.53 ppm (glutathione, GSH) (27) (assignments listed in Fig. 1D).…”

“…Having found that MMC were sensitive to inhibition of acetate transport using a MCT1 inhibitor (CHC), we next evaluated effects of blocking acetate incorporation into membrane long-chain fatty acids (- 13 CH 2 - and 13 CH 3 ) (precursors to membrane biogenesis (11, 27)), by using the FASN inhibitor orlistat (Fig. 2A and 2C).…”

Analytical strategies for studying stem cell metabolism

“…Additionally, an MS-based analysis has shown that the distribution of phosphatidylcholines and phosphatidylethanolamines, components of MLs, is significantly altered between embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), suggesting that differences in lipid metabolism, among others, may be linked to important regulatory differences underlying ESC and iPSC biology (Meissen et al, 2012). Interestingly, there have also been reports that MLs are elevated in glioblastoma cancer stem cells; however, as different groups have published conflicting results, it remains to be seen whether MLs are a marker of sternness or apoptosis (Ramm et al, 2011; Loewenbrück et al, 2011; Guidoni et al, 2014). In addition to lipogenesis, there are important studies outlining changes in energy metabolism between differentiated cells and stem cells (Fig.…”