Association of intermediates of bioenergetic pathways and plasma metabolomics with colorectal cancer (CRC): Diagnosis, stage, and survival.
Authors: Gangi Alexandra , Kim Daniel Myung , Aguirre Francesca Paola , Alvarez Rocio , Zhou Lisa , ten Hoeve Johanna , Liao Yi Jou , Graeber Thomas , Cho May Thet , Abbas Anser Ali , Davelaar John , Sankar Kamya , Osipov Arsen , Hendifar Andrew Eugene , Hitchins Megan Philippa , Gong Jun 
Published: June 2023

e15575 Background: Metabolomics is an evolving technique that can offer a non-invasive method for comprehensive identification of metabolic biomarkers. We evaluated the feasibility of measuring plasma metabolites in a longitudinal, observational cohort of patients (pts) with stage I-IV CRC for association with disease characteristics and overall survival (OS). Methods: In this retrospective analysis of prospectively collected blood samples from a single-institute cohort of pts with stage I-IV CRC, up to 150 metabolites of central carbon metabolism were analyzed by mass spectrometry and high-performance liquid chromatography. All blood samples were collected at pre-chemotherapy baseline. Analytes were compared by relative area under the curve (AUC) and differences evaluated by ANOVA. Blood samples were collected from two non-CRC pts to serve as healthy controls. Comparison of plasma metabolite levels were stratified by diagnosis of CRC vs. healthy control, non-metastatic CRC (stage I-III) vs. metastatic CRC (stage IV), and short OS vs. long OS (defined by the median threshold OS of 24.8 months in the cohort). Results: Plasma metabolomics was performed on a total of 32 pts with CRC. The median age of the cohort was 65 years (range 20-90) with the majority being female (53%) and having stage IV disease (78%). Of 25 pts with stage IV CRC, 88% had pre-chemotherapy blood samples collected in the first-line setting and 44% were KRAS mutant compared to 37% KRAS WT and 19% unknown KRAS status. Compared to healthy controls, CRC pts had higher levels of glutamate, nucleotides UMP and CMP, and nucleosides hypoxanthine and inosine (all p < 0.05). When stratified by stage, stage I-III CRC pts had higher levels of the non-essential amino acid (AA) serine and essential AAs threonine and methionine, while stage IV had higher levels of the aldopentose ribose (all p < 0.05) Those with short OS had increased levels in intermediates of glycolysis (lactate, UDP-Glc), glutamine metabolism (GlcNAc), MTA cycle (SAM, 5-Methioadenosine), and pentose phosphate pathway (R5P) as well as increased levels of proline (non-essential AA), phenylalanine (essential AA), thymine (nucleobase), and UDP (nucleotide) compared to pts with long OS (all p < 0.05). Notably, both stage IV and short OS pts had trends in increased intermediates of glutamine metabolism (glutamate, a-KG, UDP-GlcNAc) that did not reach significance. Conclusions: We show that pts with CRC compared to healthy controls and those with stage IV and short OS appear to be enriched in intermediates of multiple bioenergetic pathways including AA synthesis, nucleotide synthesis, glycolysis, methyl donor biology, and glutamine signaling. These findings are hypothesis-generating and can inform more focused evaluation of potential biomarkers and therapeutic targets in CRC.