Nicotinamide metabolism alterations in bladder cancer: Preliminary studies.

OBJECTIVES: Cancer is one of the main cause of death in Western countries. Inflammation plays an important role in the pathogenesis of cancer. Nicotinamide (NA) - known for its anti-inflammatory properties - participates in the processes related to the cell cycle regulation and DNA repair, which are relevant in cancer development. This study aimed to investigate the nicotinamide metabolism alterations in bladder cancer.

METHODS: Blood and plasma samples of patients with bladder cancer were collected. Blood pyridine and adenine nucleotides concentration were measured using high performance liquid chromatography (HPLC). Plasma nicotinamide metabolites concentration were determined using high performance liquid chromatography - mass spectrometry (LC/MS).

RESULTS: Our results indicated that the development of bladder cancer caused significant decrease in the concentration of N-methylnicotinamide (MetNA) (0.07 ± 0.02 vs 0.1 ± 0.03 µmol/l) and an increase in the concentration of N-methyl-2-pyridone-5-carboxamide (Met2PY) - one of the final nicotinamide metabolites: (1.1 ± 0.15 vs 0.7 ± 0.07 µmol/l) in comparison to the control. The association between the stage of cancer and the increase in both, Met2PY and Met4PY levels was observed. Blood ATP and NAD levels were significantly decreased in bladder cancer patients as compared to the control (970.8 ± 77.84 vs 1165.00 ± 57.76 µmol/l; 45.86 ± 2.98 vs 53.06 ± 2.28 µmol/l respectively).

CONCLUSIONS: Bladder cancer development caused substantial changes in nicotinamide metabolism, such as decreased plasma MetNA and increased Met2PY concentration. Analysis of the nicotinamide and its metabolites concentrations - as new biomarkers - may allow to track the course of pathological processes in cancer.