Agilent dd2 600 spectrometer

The ¹³C cross polarization (CP) magic angle spinning (MAS) Nuclear magnetic resonance spectroscopy (NMR) measurements were performed using an Agilent DD2 600 spectrometer (Agilent Technologies, USA), with magnetic flux density of 14.1 T and equipped with a 3.2 mm T3 MAS NMR probe operating in double resonance mode. The MAS rate in experiments was 10 kHz, the number of scans was 10 000 with a 6.0 s delay between successive scans, and CP contact time was 1.3 ms. The spectra were processed using TopSpin 3.5 and OriginPro 2017 software. Deconvolution of the peak was carried out using OriginPro 2017 software (Multiple Peak Fit) and Gaussian functions. Deconvolution was performed based on the studies of Duer et al.^{34 (link)} and Idris et al.^{12 (link)}

Quantitative analysis of cell extracts as well as extracts of snap-frozen tumors was performed by ¹H-NMR spectroscopy (Additional file 1: Method 4). Spectra were recorded at 600 MHz using an Agilent DD2 600 spectrometer (Agilent Technologies, Santa Clara, California, USA). In addition, for dedicated analysis of glucose uptake and the intratumoral immune cell infiltrate, a co-staining of the glucose transporters GLUT1 and GLUT3 and the T-cell marker CD3 was conducted (Additional file 1: Method 5). While exemplary ROIs are presented within the respective figures, total cross-sections of the co-stained tumor tissue are shown in Additional file 1: Figure S3. For further analysis of the intratumoral glucose accumulation, quantitative MALDI-2-MSI of tumor sections was performed using isotopically labeled standard and a novel tandem-MS based method (Additional file 1: Method 6) [26 (link)].