Lipidomic Signatures for Colorectal Cancer Diagnosis and Progression Using UPLC-QTOF-ESI+MS

Abstract

Metabolomics coupled with bioinformatics may identify relevant biomolecules such as putative biomarkers of specific metabolic pathways related to colorectal diagnosis, classification and prognosis. This study performed an integrated metabolomic profiling of blood serum from 25 colorectal cancer (CRC) cases previously classified (Stage I to IV) compared with 16 controls (disease-free, non-CRC patients), using high-performance liquid chromatography and mass spectrometry (UPLC-QTOF-ESI+ MS). More than 400 metabolites were separated and identified, then all data were processed by the advanced Metaboanalyst 5.0 online software, using multi- and univariate analysis, including specificity/sensitivity relationships (area under the curve (AUC) values), enrichment and pathway analysis, identifying the specific pathways affected by cancer progression in the different stages. Several sub-classes of lipids including phosphatidylglycerols (phosphatidylcholines (PCs), phosphatidylethanolamines (PEs) and PAs), fatty acids and sterol esters as well as ceramides confirmed the “lipogenic phenotype” specific to CRC development, namely the upregulated lipogenesis associated with tumor progression. Both multivariate and univariate bioinformatics confirmed the relevance of some putative lipid biomarkers to be responsible for the altered metabolic pathways in colorectal cancer.

The Application of Metabolomics in Recent Colorectal Cancer Studies: A State-of-the-Art Review

“…In our review, most studies employed a type of mass spectrometry analysis, with three studies employing 1 H-NMR analysis [29,42,53]. Liquid-Chromatography-Mass Spectrometry (LCMS), including Ultra-High Performance Liquid Chromatography-Mass Spectrometry (UHPLC-MS) and Liquid Chromatography-High Resolution Mass Spectrometry (LC-HRMS), was the most popular method for analysis, with eighteen identified studies that applied this technique [22][23][24]26,30,31,33,35,36,38,39,41,43,[47][48][49][50]52], followed by Gas Chromatography-Mass Spectrometry, which was conducted in seventeen studies [24,25,27,28,34,38,39,[44][45][46][48][49][50][51]54,56,57] (Figure 2b). These counts include four studies conducting both LCMS and GCMS.…”

“…Other methods of analysis included direct infusion mass spectrometry (1 study) [32], Capillary electrophoresis-time of flight mass spectrometry (CE-TOFMS) (3 studies) [37,40,55], and Matrix Assisted Laser Desorption Ionization-Time of Flight mass spectrometry (MALDI-TOF MS) (1 study) [58] (Figure 2b). Thirty studies [23][24][25][27][28][29][30][31][32][34][35][36][37][38][39][40][42][43][44][45][46][48][49][50]53,54,[56][57][58] employed untargeted metabolomic profiling, while 9 studies employed targeted metabolomics, either with a metabolite subset in mind to begin the study or as part of a validation of their untargeted data [22,25,26,28,35,47,51,52,55]. Of studies where the selections of analytical columns could be identified, 16 used a column that could identify polar and nonpolar compounds …”

“…Thirty studies [23][24][25][27][28][29][30][31][32][34][35][36][37][38][39][40][42][43][44][45][46][48][49][50]53,54,[56][57][58] employed untargeted metabolomic profiling, while 9 studies employed targeted metabolomics, either with a metabolite subset in mind to begin the study or as part of a validation of their untargeted data [22,25,26,28,35,47,51,52,55]. Of studies where the selections of analytical columns could be identified, 16 used a column that could identify polar and nonpolar compounds [22,[25][26][27][28]31,33,36,38,…”

“…Of studies where the selections of analytical columns could be identified, 16 used a column that could identify polar and nonpolar compounds [22,[25][26][27][28]31,33,36,38,39,44,48,49,51,55,58], 8 focused on polar compounds [23,24,30,34,47,52,54], and 2 used nonpolar compounds [45,46]. Additionally, six studies [23,25,52,[56][57][58] conducted lipidomics, a subset of metabolomics specifically targeted at lipid identification, as the lipidome is often perturbed in CRC patients [59]. Song et al, in addition to finding two individual fatty acids expressed differently in CRC compared to control in male participants, also found that the total levels of ω-6 polyunsaturated fatty acids as well as total monounsaturated fatty acids were raised in male CRC patients compared to control [57].…”

“…Most studies employed a case-control research design, using either a healthy (carcinoma-free) control, adenomatous polyp group, or both. Twenty-one studies compared CRC directly to healthy control [24][25][26]31,33,36,38,39,[42][43][44][45][46][48][49][50][51][52][53][54]56]. Jing et al and Gao et al, conversely, compared CRC patients to an adenomatous polyp control [32,55] while eleven studies utilized CRC, healthy control, and adenomatous polyp groups [28][29][30]34,35,37,40,41,47,57,58].…”