Multiplatform Urinary Metabolomics Profiling to Discriminate Cachectic from Non-Cachectic Colorectal Cancer Patients: Pilot Results from the ColoCare Study

Cachexia is a multifactorial syndrome that is characterized by loss of skeletal muscle mass in cancer patients. The biological pathways involved remain poorly characterized. Here, we compare urinary metabolic profiles in newly diagnosed colorectal cancer patients (stage I–IV) from the ColoCare Study in Heidelberg, Germany. Patients were classified as cachectic (n = 16), pre-cachectic (n = 13), or non-cachectic (n = 23) based on standard criteria on weight loss over time at two time points. Urine samples were collected pre-surgery, and 6 and 12 months thereafter. Fat and muscle mass area were assessed utilizing computed tomography scans at the time of surgery. N = 152 compounds were detected using untargeted metabolomics with gas chromatography–mass spectrometry and n = 154 features with proton nuclear magnetic resonance spectroscopy. Thirty-four metabolites were overlapping across platforms. We calculated differences across groups and performed discriminant and overrepresentation enrichment analysis. We observed a trend for 32 compounds that were nominally significantly different across groups, although not statistically significant after adjustment for multiple testing. Nineteen compounds could be identified, including acetone, hydroquinone, and glycine. Comparing cachectic to non-cachectic patients, higher levels of metabolites such as acetone (Fold change (FC) = 3.17; p = 0.02) and arginine (FC = 0.33; p = 0.04) were observed. The two top pathways identified were glycerol phosphate shuttle metabolism and glycine and serine metabolism pathways. Larger subsequent studies are needed to replicate and validate these results.

Associations of branched-chain amino acids with parameters of energy balance and survival in colorectal cancer patients: Results from the ColoCare Study

BACKGROUND

Branched-chain amino acids (BCAA) have been previously linked to survival in colorectal cancer (CRC) patients. It is unclear whether BCAAs are prognostic biomarkers or surrogate markers for energy balance.

OBJECTIVES

We aimed to determine correlations of BCAAs with markers of energy balance over time and to investigate prognostic significance of BCAAs in CRC.

METHODS

We used urinary samples from newly diagnosed CRC patients [n=163; (stage I - IV)] from the ColoCare study in Heidelberg, Germany, collected at surgery (n=163), 6 (n=83) and 12 months follow-up (n=54). Isoleucine, leucine, valine, (2Z)-3-methylglutaconic acid (3HM), 2-ethylhydracrylic acid (2EA), 2-methyl-3-hydroxybutyrate (2M3H) were detected using gas-chromatography mass-spectrometry and proton-nuclear-magnetic-resonance spectroscopy. Partial correlation coefficients between BCAAs with body mass index (BMI), physical activity (metabolic equivalent [MET]) and muscle area were computed and adjusted for sex and age at diagnosis. We used Cox proportional hazard models to investigate overall survival (OS) after 24 months of follow-up.

RESULTS

We did not observe significant correlations between BCAAs and parameters of energy balance at all time points (correlation ranges: BMI: r= -0.13 to -0.01; METs: r=-0.14 to 0.02; dorsal muscle: r=-0.03 to 0.10). BCAAs were not associated with risk of death in stage I-III (e.g., valine: HR_log2=1.62, p=0.25) or in stage IV tumors. Elevated concentrations of 2EA and 2M3H were significantly associated with OS, independent of stage (2EA: stage I-III: HR_log2=0.42, p=0.04; stage IV: HR_log2=0.51, p=0.01).

CONCLUSION

Our study suggests that BCAAs in colorectal cancer patients do not reflect parameters of energy balance and may be independently associated with overall survival.

Abstract 4282: Branched-chain amino acids in the urinary metabolic profile of colorectal cancer patients and associations with muscle mass, BMI, and physical activity in the ColoCare Study

Background

Branched-chain amino acids (BCAA; e.g., valine, leucine and isoleucine) have been previously linked with survival in colorectal cancer patients. It is unclear whether BCAAs are prognostic biomarkers or a surrogate endpoint for factors related to muscle mass. Thus, we investigated the correlation between BCAAs and muscle mass, physical activity and body mass index (BMI) at multiple time points during the course of disease in a prospective cohort of patients.

Methods

Patients with newly diagnosed colorectal cancer [n = 197; (stage I - IV)] from the ColoCare study in Heidelberg, Germany with baseline and follow-up data, and measurements of urinary BCAAs were eligible. Skeletal muscle mass of the dorsal muscle was quantified based on abdominal computed tomography (CT)-scans (vertebral body L3/4 and L4/5). BMI (kg/m2) and physical activity [metabolic equivalent (MET) hours/week] were reported by questionnaire. In addition, minutes of moderate and vigorous physical activity/week were measured by accelerometry. We prospectively monitored the urinary metabolome of these patients at multiple time points after surgery [baseline (n = 197), 6-month follow-up (n = 107) and 12 month follow-up (n = 75)]. BCAAs (valine, leucine and isoleucine) were identified using gas chromatography mass spectrometry (GC/MS). Metabolites were normalized based on the sum intensity of all annotated metabolites for statistical analyses. Pearson and partial correlation coefficients with parameters of energy balance/muscle mass were computed for each time point, adjusted for gender and age at diagnosis.

Results

As expected, urinary valine, leucine and isoleucine were highly correlated, independent of time point (r>0.95, P<0.01). There were no statistically significant correlations between BCAA and parameters of energy balance or muscle mass at baseline, 6 months, or 12 months (ranges of correlations for muscle mass: r = -0.17 to -0.04; for self-reported physical activity, MET hours/week r = -0.006 to -0.04, accelerometry-based moderate physical activity: r = -0.21 to-0.10; BMI: r = -0.05 to 0.09).

Conclusion

The present data suggests that urinary levels of BCAA in colorectal cancer patients do not reflect parameters of energy balance and muscle mass. Thus, they warrant further investigation as potential prognostic biomarkers.

Citation Format: Jennifer Ose, David B. Liesenfeld, Juergen Boehm, Nina Habermann, Robert W. Owen, Biljana Gigic, Stefanie Skender, Johanna Nattenmueller, Hans-Ulrich Kauczor, Cornelia Ulrich. Branched-chain amino acids in the urinary metabolic profile of colorectal cancer patients and associations with muscle mass, BMI, and physical activity in the ColoCare Study. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4282.

Aspirin Reduces Plasma Concentrations of the Oncometabolite 2-Hydroxyglutarate: Results of a Randomized, Double-Blind, Crossover Trial

BACKGROUND

Aspirin use is an effective strategy for the chemoprevention of colorectal cancer, even at low doses. However, in order to implement aspirin interventions, risk-benefit balances and biologic mechanisms need to be better defined; to further this aim, we used a metabolomics approach.

METHODS

We metabolically profiled 40 healthy, nonsmoking men and women ages 20 to 45 years enrolled in a randomized, double-blind, crossover trial of 325 mg aspirin/day over a period of 60 days. Gas and liquid chromatography-mass spectrometry were used to comprehensively profile participants' plasma samples after aspirin and placebo interventions.

RESULTS

A total of 363 metabolites, covering most human biochemical pathways, were measured. Compared with placebo-treated participants, plasma concentrations of the oncometabolite 2-hydroxyglutarate (R+S) decreased after aspirin treatment in both men and women (P = 0.005). This signal proved robust during 20-fold random splitting of the data using 80% of the samples in each split. We subsequently performed functional follow-up studies using targeted, enantiospecific detection in human colorectal cancer cell lines and observed an aspirin-induced reduction of (R)-2-hydroxyglutarate. We further showed that salicylate, the primary aspirin metabolite, inhibits the hydroxyacid-oxoacid transhydrogenase mediated production of (R)-2-hydroxyglutarate, thereby providing mechanistic evidence for the clinically observed effects of aspirin on total-2-hydroxyglutarate.

CONCLUSIONS

Using a metabolomics approach with functional follow-up, we propose that a decrease in the oncometabolite (R)-2-hydroxyglutarate may identify an additional mechanism for aspirin or its metabolites in cancer prevention.

IMPACT

Reduction of the oncometabolite (R)-2-hydroxyglutarate identifies a novel, non-COX-inhibition-mediated mechanism of aspirin.

Abstract 3445: Diacylglycerol kinase alpha as a novel epigenetically regulated risk marker for radiotherapy-induced fibrosis

Ionizing radiation is a common treatment option for cancer but its use is limited by the unpredictable and highly heterogeneous onset of late side effects, especially radiation-induced fibrosis. Clinically applicable biomarkers and effective treatments for radiation fibrosis are currently unavailable. In order to identify novel markers we ran a genome-wide DNA methylation screen in primary dermal fibroblasts obtained from breast cancer patients before intraoperative radiotherapy. Cells from patients developing fibrosis within a three-year follow up were compared to those without fibrosis (12 individuals per group). Illumina Infinium HumanMethylation450 BeadChip analysis revealed differentially methylated sites which are associated with fibrosis. Notably, we identified a differentially methylated region (DMR) at the diacylglycerol kinase alpha (DGKA) locus as a potential fibrosis marker. This DGKA DMR was confirmed using quantitative MassARRAY technology in 75 patient fibroblast samples. We first investigated whether high or low DNA methylation at this DGKA DMR affects cellular radiation response. Functional in vitro analysis showed that the methylation status of the DGKA DMR inversely correlated with its radiation-induced mRNA and protein expression as well as with its enzymatic activity. We next examined the DMR for its role as a regulatory site. The intragenically located DMR was identified as a potential enhancer sequence using chromatin immunoprecipitation (ChIP) for H3K4me1 and H3K27ac as well as luciferase reporter assays. Chromatin conformation capture (3C) analysis revealed interaction of this enhancer with the DGKA promoter in fibroblasts with low DNA methylation, and further ChIP experiments showed a DNA methylation-dependent recruitment of the profibrotic transcription factor Early Growth Response 1 (EGR1) to this site. We finally asked how epigenetically altered DGKA expression could impact on cellular processes relevant to fibrosis such as fibroblast transactivation or stress response. Results in primary fibroblasts showed that, in response to ionizing radiation and other stress factors, DGKA affects global levels of its substrate diacylglycerol, as well as expression of the fibroblast activation markers Alpha Smooth Muscle Actin (ACTA2) and collagen 1 (COL1A1). Upon overexpression of DGKA in HEK293T cells, a luciferase-based screening of 15 stress-responsive signaling reporters revealed functional consequences on several response pathways. In summary, DGKA has emerged as a novel, epigenetically regulated signaling protein that has a role in radiation fibrosis and may serve as a new biomarker and therapeutic target.

Citation Format: Christoph Weigel, Marlon R. Veldwijk, Christopher C. Oakes, Petra Seibold, Alla Slynko, David B. Liesenfeld, Carsten Herskind, Elena Sperk, Axel Benner, Christoph Plass, Frederik Wenz, Jenny Chang-Claude, Peter Schmezer, Odilia Popanda. Diacylglycerol kinase alpha as a novel epigenetically regulated risk marker for radiotherapy-induced fibrosis. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3445. doi:10.1158/1538-7445.AM2015-3445

Metabolomics and transcriptomics identify pathway differences between visceral and subcutaneous adipose tissue in colorectal cancer patients: the ColoCare study

BACKGROUND

Metabolic and transcriptomic differences between visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) compartments, particularly in the context of obesity, may play a role in colorectal carcinogenesis. We investigated the differential functions of their metabolic compositions.

OBJECTIVES

Biochemical differences between adipose tissues (VAT compared with SAT) in patients with colorectal carcinoma (CRC) were investigated by using mass spectrometry metabolomics and gene expression profiling. Metabolite compositions were compared between VAT, SAT, and serum metabolites. The relation between patients' tumor stage and metabolic profiles was assessed.

DESIGN

Presurgery blood and paired VAT and SAT samples during tumor surgery were obtained from 59 CRC patients (tumor stages I-IV) of the ColoCare cohort. Gas chromatography time-of-flight mass spectrometry and liquid chromatography quadrupole time-of-flight mass spectrometry were used to measure 1065 metabolites in adipose tissue (333 identified compounds) and 1810 metabolites in serum (467 identified compounds). Adipose tissue gene expression was measured by using Illumina's HumanHT-12 Expression BeadChips.

RESULTS

Compared with SAT, VAT displayed elevated markers of inflammatory lipid metabolism, free arachidonic acid, phospholipases (PLA2G10), and prostaglandin synthesis-related enzymes (PTGD/PTGS2S). Plasmalogen concentrations were lower in VAT than in SAT, which was supported by lower gene expression of FAR1, the rate-limiting enzyme for ether-lipid synthesis in VAT. Serum sphingomyelin concentrations were inversely correlated (P = 0.0001) with SAT adipose triglycerides. Logistic regression identified lipids in patients' adipose tissues, which were associated with CRC tumor stage.

CONCLUSIONS

As one of the first studies, we comprehensively assessed differences in metabolic, lipidomic, and transcriptomic profiles between paired human VAT and SAT and their association with CRC tumor stage. We identified markers of inflammation in VAT, which supports prior evidence regarding the role of visceral adiposity and cancer.

Changes in urinary metabolic profiles of colorectal cancer patients enrolled in a prospective cohort study (ColoCare)

INTRODUCTION

Metabolomics is a valuable tool for biomarker screening of colorectal cancer (CRC). In this study, we profiled the urinary metabolomes of patients enrolled in a prospective patient cohort (ColoCare). We aimed to describe changes in the metabolome in the longer clinical follow-up and describe initial predictors as candidate markers with possibly prognostic significance.

METHODS

In total, 199 urine samples from CRC patients pre-surgery (n=97), 1-8 days post-surgery (n=12) and then after 6 and 12 months (n=52 and 38, respectively) were analyzed using both GC-MS and ¹H-NMR. Both datasets were analyzed separately with built in uni- and multivariate analyses of Metaboanalyst 2.0. Furthermore, adjusted linear mixed effects regression models were constructed.

RESULTS

Many concentrations of the metabolites derived from the gut microbiome were affected by CRC surgery, presumably indicating a tumor-induced shift in bacterial species. Associations of the microbial metabolites with disease stage indicate an important role of the gut microbiome in CRC.We were able to differentiate the metabolite profiles of CRC patients prior to surgery from those at any post-surgery timepoint using a multivariate model containing 20 marker metabolites (AUCROC=0.89; 95% CI:0.84-0.95).

CONCLUSION

To the best of our knowledge, this is one of the first metabolomic studies to follow CRC patients in a prospective setting with repeated urine sampling over time. We were able to confirm markers initially identified in case-control studies and pin point metabolites which may serve as candidates for prognostic biomarkers of CRC.

Review of mass spectrometry-based metabolomics in cancer research

Metabolomics, the systematic investigation of all metabolites present within a biologic system, is used in biomarker development for many human diseases, including cancer. In this review, we investigate the current role of mass spectrometry-based metabolomics in cancer research. A literature review was carried out within the databases PubMed, Embase, and Web of Knowledge. We included 106 studies reporting on 21 different types of cancer in 7 different sample types. Metabolomics in cancer research is most often used for case-control comparisons. Secondary applications include translational areas, such as patient prognosis, therapy control and tumor classification, or grading. Metabolomics is at a developmental stage with respect to epidemiology, with the majority of studies including less than 100 patients. Standardization is required especially concerning sample preparation and data analysis. In the second part of this review, we reconstructed a metabolic network of patients with cancer by quantitatively extracting all reports of altered metabolites: Alterations in energy metabolism, membrane, and fatty acid synthesis emerged, with tryptophan levels changed most frequently in various cancers. Metabolomics has the potential to evolve into a standard tool for future applications in epidemiology and translational cancer research, but further, large-scale studies including prospective validation are needed.