Development of Urinary Pseudotargeted LC-MS-Based Metabolomics Method and Its Application in Hepatocellular Carcinoma Biomarker Discovery

Hepatocellular
carcinoma (HCC) is one of the pestilent malignancies
leading to cancer-related death. Discovering effective biomarkers
for HCC diagnosis is an urgent demand. To identify potential metabolite
biomarkers, we developed a urinary pseudotargeted method based on
liquid chromatography–hybrid triple quadrupole linear ion trap
mass spectrometry (LC–QTRAP MS). Compared with nontargeted
method, the pseudotargeted method can achieve better data quality,
which benefits differential metabolites discovery. The established
method was applied to cirrhosis (CIR) and HCC investigation. It was
found that urinary nucleosides, bile acids, citric acid, and several
amino acids were significantly changed in liver disease groups compared
with the controls, featuring the dysregulation of purine metabolism,
energy metabolism, and amino metabolism in liver diseases. Furthermore,
some metabolites such as cyclic adenosine monophosphate, glutamine,
and short- and medium-chain acylcarnitines were the differential metabolites
of HCC and CIR. On the basis of binary logistic regression, butyrylcarnitine
(carnitine C4:0) and hydantoin-5-propionic acid were defined as combinational
markers to distinguish HCC from CIR. The area under curve was 0.786
and 0.773 for discovery stage and validation stage samples, respectively.
These data show that the established pseudotargeted method is a complementary
one of targeted and nontargeted methods for metabolomics study.