Human prostate cancer is the second commonest cause of cancer death in males in the UK¹. NMR spectroscopy methods have been used to differentiate between benign prostate hypertrophy (BPH) and malignant prostate cancer samples Spermine, which is found to be reduced in prostate cancer tissue samples, when measured by High-Resolution Magic Angle Spinning (HRMAS) ¹H NMR showed a linear correlation with the volume percentage of normal epithelial cells that were quantified by histopathology methods². These studies along with others were aimed at establishing non-invasive magnetic resonance methods either to distinguish normal from benign (and also from malignant) tissue or to follow the metabolic changes with the progression of malignance/aggressiveness (factors such as malignancy, cellularity and Gleason’s grade) of the prostate cancer^3-7.

There is no data available as to how the metabolism of prostate is affected by the Degarelix treatment in human prostate cancer tissues. In this context, HRMAS ¹H NMR spectroscopic method was used to analyse surgically resected human benign and high grade prostate cancer samples with and without Degarelix treatment (removed surgically 7 days after administration of degarelix with confirmed castrate levels of serum testosterone) in order to evaluate the metabolic changes associated with medical castration.

Full ethical approval was obtained for all elements of the study. Twenty three post-surgical prostate samples were snap frozen in cryogenic vials and preserved at -80°C until the NMR analysis. One tissue sample was analysed at a time by transferring it on the dry ice. Sample was cut to the size to fit into the 4mm plastic insert. The capped insert was inserted into the HRMAS rotor. The top screw of the rotor was fitted and placed into the NMR spectrometer. In this study, HRMAS 1H NMR data from benign (n=10), high grade (n= 7) and Degarelix treated HG (n=6) were obtained.

Metabolite data acquisition and analysis HRMAS ¹H NMR data acquisition was performed on a Bruker 600MHz, with a 4mm HRMAS probe. All the spectra were obtained using TOPSPIN 2.5 Bruker software and at a spin rate of 3000Hz and a sample temperature at 4°C. Water suppressed pulse sequence (Bruker Topspin refers it as zgpr) with acquisition parameters of a repetition time of 8sec, 128 transients, 64K time domain points were used to get the metabolite spectrum. Corresponding water spectrum was acquired with 8sec repetition time, 8 transients and 64K time domain points. A water suppressed CPMG pulse sequence with acquisition parameters of 8sec repetition time, 128 transients and 64K time domain points was used with a T₂ filter (TE= 50ms, 100ms and 200ms) to acquire metabolite spectrum with the suppression of the broad lipid and macromolecule signals. The total analysis time for each sample was about one hour thirty minutes.

We analysed the metabolite profiles, obtained by using a water suppressed CPMG pulse sequence with a T2 filter of 200 microseconds from samples, with Principal Component analysis (PCA) and Orthogonal projections to latent structures – discriminant analysis (OPLS-DA). The spectra were binned from 0.5ppm to 4.5ppm with 0.01ppm intervals. Binned data was exported to SIMCA (Umetrics®) software for multivariate analysis. All the bins were mean centred (with pareto scaling). Scores plots were used for classification of the samples and loadings plots to identify the metabolites responsible for the separation of samples in the scores plots.