A study of low-molecular-weight organic acid urinary profiles in prostate cancer by a new liquid chromatography-tandem mass spectrometry method.

Metabolomic studies constantly require high throughput screenings, and this drives development and optimization of methods that include more analytes in a single run, shorten the analysis time and simplify sample preparation. The aim of the study was to develop a new simple and fast liquid chromatography-tandem mass spectrometry-based methodology for quantitative analysis of a panel of ten organic acids in urine. The metabolites selected for the study include ten molecules potentially associated with cancer development. Chromatographic separation involved a Phenomenex Synergi Hydro-RP column under gradient conditions. Quantitation of the analytes was performed in multiple reaction monitoring mode under negative ionization. Validation parameters were satisfactory and in line with the international guidelines. The methodology enabled us to analyze urine samples collected from prostate cancer (PC) (n = 49) and benign prostate hyperplasia (BPH) (n = 49) patients. The obtained concentrations were normalized with urinary specific gravity (USG) prior to statistical analysis. Five analytes were quantified in all urine samples and we observed the following USG-normalized concentration ranges: citric acid (146.5-6339.8), 3-hydroxyisobutyric acid (22.5-431.7), 2-ketoglutaric acid (4.4-334.4), lactic acid (10.1-786.3), succinic acid (4.1-500.5). 3-hydroxyisobutyric acid significantly decreased between two groups of prostate cancer patients: ≥7 Gleason patients and <7 Gleason patients. Quick sample preparation limited to "dilute and shoot" makes the developed methodology a great tool for future metabolomic studies, especially for detecting disturbances in energy metabolism (Krebs cycle) and amino acids metabolism. The research also broadens our knowledge on the alteration of selected organic acids in PC and BPH patients.