Complementary Glycomic Analyses of Sera Derived from Colorectal Cancer Patients by MALDI-TOF-MS and Microchip Electrophoresis

Abstract

Colorectal cancer is the fourth most prevalent cancer in the United States, yet there are no reliable non-invasive early screening methods available. Serum-based glycomic profiling has the necessary sensitivity and specificity to distinguish disease states and provide diagnostic potential for this deadly form of cancer. We applied microchip electrophoresis and MALDI-TOF-MS-based glycomic procedures to 20 control serum samples and 42 samples provided by patients diagnosed with colorectal cancer. Within the identified glycans, the position of fucose units was located to quantitate possible changes of fucosyl isomeric species associated with the pathological condition. MALDI-MS data revealed several fucosylated tri- and tetra-antennary glycans which were significantly elevated in their abundance levels in the cancer samples and distinguished the control samples from the colorectal cancer cohort in the comprehensive profiles. When compared to other cancers studied previously, some unique changes appear to be associated with colorectal cancer, being primarily associated with fucosyl isomers. Through MS and microchip electrophoresis-based glycomic methods, several potential biomarkers were identified to aid in the diagnosis and differentiation of colorectal cancer. With its unique capability to resolve isomers, microchip electrophoresis can yield complementary analytical information to MS-based profiling.

Capillary electrophoresis–mass spectrometry for direct structural identification of serum N-glycans

“…We assigned electrophoretic mobilities to these structures and possible isomers in electropherograms by matching the electrophoretic mobilities of known N-glycans (referred to as electrophoretic mobility standards) to the electrophoretic mobilities of unknown structures. 39–40 …”

Capillary electrophoresis with stationary nanogel zones of galactosidase and Erythrina cristagalli lectin for the determination of β(1–3)-linked galactose in glycans

“…Enzyme analyses of this type are performed off-line, with any change in the glycan size detected by a shift in the migration time obtained with capillary electrophoresis. [10–17] Offline enzyme reactions are conducted for incubation times of several hours and consume significant enzyme quantities. Although most off-line exoglycosidase analyses are performed on glycans derived from glycoproteins, analyses of intact proteins can be accomplished with capillary electrophoresis.…”

Recent Advances in the Mass Spectrometry Methods for Glycomics and Cancer

“…55 CE compliments the rapid compositional capabilities of MALDI-MS. The microchip electrophoresis can separate structural isomers, which could be more specific toward individual diseases.…”

“…This study identified tri- and tetra-antennary fucosylated glycans that were significantly elevated in cancer samples when compared to the controls. 55 …”