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Metabolomics: A Novel Platform for Environmental Health Investigations? CN ONG, FG Xu, L Zou, Y Liu, Department of Epidemiology & Public Health National University of Singapore & Singapore-MIT Alliance on Research and Technology Toxicology programme, Life Sciences Institute National University of Singapore Building Blocks of Life Marth, JD Nature Cell Biology 10, 1015 (2008) Bio-nomics Family Genomics Transcriptomics Proteomics DNA Phenotypes Functions Metabolomics RNA Proteins Sugars/Carbohydrates Fats/lipids Nucleotides Amino Acids Metabolites Genomics and proteomics tell you what might happen, but metabolomics tells you what actually did happen! Bill Lasley, University of California, Davis Classification of Metabolomics Metabolomics Metabonomics Metabolite target analysis Metabolic profiling Metabolic fingerprinting Metabolome Specific metabolites Group of compounds or metabolites in cell/system or biofluids Quantification of set of metabolites present in a cell/sample Xenobiotica 1999,29: 1181; Nature 2008, 455:2054 Sample classification by rapid, global analysis Metabolomics-related papers published between 1999-2009 (ISIS web of science) Xu et al., Trends Anal. Chem. 2010, 29: 269 General Workflow of Metabolomics Time course Dose response Exogenous Toxins, Drugs Environmental etc Bio-systems m* p* t* 8 7 6 5 4 3 2 1 t[2] Analytical Approaches 0 -1 -2 -3 -4 -5 -6 -7 -8 -10 Endogenous -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 R2X[2] = 0.166547 SIMCA-P+ 11 - 9/2/2008 5:16:56 PM •Exposure assessment •Bio-monitoring •Disease diagnostics Metabolic pathways Databases Mol. Biosyst. 2009, 5: 288; J. Proteome. Res. 2009, 8: 5657; 2009, 8: 352. 9 t[1] R2X[1] = 0.203804 Examples • • • • • Zebrafish- liver Smoking - urine Chronic kidney disease- urine Cataract - urine Colorectal cancer - tissues (A) 5 4 20000000 6 51 2 3 9 1 3 7 2 1 1 10000000 1 10000000 1 0 5.0 ppm (t1) 8 0 4.0 3.0 2.0 1.0 pp m 7 (B) 4 1 3 1 2 7 3 6 5000000 2 5 6 1 5 9 4 3 8 10 2 11 1 0 5.0 ppm (t1) 4.0 3.0 2.0 1.0 pp m 0 -1 -2 -3 1H NMR (800 MHz) profile of (A) Male and (B) Female -4 -5 Zebrafish Livers OPLS (GC/MS) -6 -7 -7 -6 -5 -4 -3 -2 -1 0 M* Ong ES et al Mol. Biosystems, 2009;5:288-98. 1 2 F* 3 4 5 6 SIMCA-P+ 11 - 3/5/2010 1:30:01 PM 7 Urine of Non-smokers vs Smokers- OPLS (LC/MS) 75 smokers 168 cases 10 9 8 7 6 5 4 3 2 1 0 -1 -2 -3 -4 -5 -6 -7 -8 93 non-smokers -9 -10 -4 -3 -2 -1 0 NC* 1 SC* 2 3 SIMCA-P+ 11 - 3/5/2010 1:24:23 PM 4 Urine of Chronic kidney disease (CKD) OPLS (LC/MS) 10 0 Control (48) -10 -10 -9 -8 -7 -6 CKD (48) -5 -4 -3 -2 -1 CN* 0 1 2 CKD* 3 4 5 6 7 8 9 SIMCA-P+ 11 - 3/10/2010 3:25:38 PM 10 Urine samples - Cataract OPLS (LC/MS) 10 0 Cataract (48) -10 -8 -7 -6 -5 -4 -3 -2 -1 CN* 0 1 Control (48) 2 CAT* 3 4 5 6 7 SIMCA-P+ 11 - 3/10/2010 3:32:14 PM 8 Colorectal Cancer (CRC) • Most common cancer among males in Singapore, 18.9%, and second common among females, 14.8% • 10% for males and females in US • Interplay of environment and genetic factors • Preventable –diet and lifestyle •Precursor of ~90% of CRC is the adenomatous polyp •Adenoma to carcinoma: 7 to 10 yrs Objective We used metabolomics approach to test the hypothesis that tissues at different stages of cancer development would exhibit distinct metabolic profile. The profiles of tumor, adenomatous polyps and adjacent matched normal mucosa from 26 CRC patients using; (1) 1H NMR (2) GC/MS, and (3) LC/MS A complex step-wise series of changes in cellular proliferation and differentiation Colorectal cancer (CRC) arises as the consequence of the progressive accumulation of biomolecular alterations that lead to changes from normal colonic epithelial cells to adenoma and to adenocarcinomas. Experimental Procedure Search database for metabolites matching Samples Mucosa, Polyps, Tumors Freeze-dried Normalization of raw data Extraction Chloroform/Methanol 3:1(v/v) Statistical analysis PCA score plot m* p* t* 8 7 6 5 Reconstitute in 50 µL Acetonitrile 3 2 1 t[2] Reconstitute in 50 µL ethyl acetate 4 0 -1 -2 -3 -4 -5 -6 -7 -8 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 t[1] R2X[1] = 0.203804 8 7 6 5 4 Chemical Shift (ppm) 3 2 1 0 SIMCA-P+ 11 - 9/2/2008 5:16:56 PM Metabolite Profiling & pathway analysis BSTFA derivatization GC/MS Analysis R2X[2] = 0.166547 LC/MS Analysis Peak identification & Confirmation Comparison of GC-MS total ion chromatograms of CRC tissues from mucosa (A), polyp (B) and tumor (C) of a patient 1.2 1 0.8 0.6 0.4 0.2 0 ×107 Glucose 5 0.8 0.6 0.4 0.2 0 7 9 myo-Inositol A 11 13 15 B ×107 5 1 0.8 0.6 0.4 0.2 0 7 9 11 13 C18:0 15 C ×107 Phosphoric acid C18:1 Phenylalanine C18:2 Glutamine 5 7 9 11 C20:4 13 15 m* p* t* 8 7 6 5 4 3 2 t[2] 1 0 -1 -2 -3 -4 -5 -6 -7 -8 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 t[1] R2X[1] = 0.203804 R2X[2] = 0.166547 PCA scores plots by GC/MS SIMCA-P+ 11 - 9/2/2008 5:16:56 PM M* P* T* t[2]O 10 0 -10 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 t[1]P R2X[1] = 0.152012 R2X[2] = 0.348756 PCA scores plots by NMR SIMCA-P+ 11 - 9/10/2008 10:05:36 AM * -1 -2 -4 n=26 -3 * : P<0.001 Polyps/Mucosa -5 Carbo, nucleotides, etc. Tumors/Mucosa ?-Sitosterol Cholesterol Glycerol 1-stearate Glycerol 1-(9-octadecenoate) * * ** ** ** *** * ** ** * * * * * * * * * * * * Glycerol 1-palmitate Glycerol 2-palmitate Behenic acid(C22:0) Arachidonic acid(C20:4) Arachidic acid(C20:0) Linoleic acid(C18:2) Oleic acid(C18:1) Stearic acid(C18:0) Margaric acid(C17:0) Palmitic acid(C16:0) Myristic acid(C14:0) Lauric acid(C12:0) ** ** Amino acids Oleamide Uric acid * Phosphoric acid Inosine 6 Vitamin C * * Adenosine monophosphate Adenosine Uridine Xanthine Hypoxanthine 1 Glucose myo-Inositol ** * ** * * * * 4 Inositol monophosphate * Tyrosine Lysine Glutamine Phenylalanine 2 Methionine 3 Proline 5 * Fold Change Metabolic Profiling by GC/MS Lipids 0 -1 -2 -4 n=26 -3 * : P<0.001 Polyps/Mucosa -5 Carbo, nucleotides, etc. Tumors/Mucosa ?-Sitosterol Cholesterol Glycerol 1-stearate * * * * * * * * * Glycerol 1-(9-octadecenoate) ** ** ** *** * ** ** * * * * * ** ** 6 Glycerol 1-palmitate Glycerol 2-palmitate Behenic acid(C22:0) Arachidonic acid(C20:4) Arachidic acid(C20:0) Linoleic acid(C18:2) Oleic acid(C18:1) Stearic acid(C18:0) Margaric acid(C17:0) Palmitic acid(C16:0) Myristic acid(C14:0) Lauric acid(C12:0) Oleamide Uric acid * Phosphoric acid Inosine Amino acids Vitamin C * * Adenosine monophosphate Adenosine Uridine Xanthine Hypoxanthine 1 Glucose myo-Inositol ** * ** * * * * 4 Inositol monophosphate * Tyrosine Lysine Glutamine Phenylalanine 2 Methionine 3 Proline 5 * * Fold Change Metabolic Profiling by GC/MS Lipids 0 Otto Warburg • 1931 Nobel Prize “For his discovery of the nature and mode of action of the respiratory enzyme” Cancer was caused by altered metabolism deranged energy processing - in the cell (1930) http://nobelprize.org Liver Blood Glucose 2 NAD+ 2 NADH 6 ~P 2 Pyruvate 2 NADH 2 NAD+ 2 Lactate Cancer Cell Glucose 2 NAD+ 2 NADH 2 ~P 2 Pyruvate 2 NADH 2 NAD+ 2 Lactate JNCI 2004;96:1805-6 Nature Rev Cancer 2004;4:891-9 Low malignancy High Malignancy * -1 -2 -4 n=26 -3 * : P<0.001 Polyps/Mucosa -5 Carbo, nucleotides, etc. Tumors/Mucosa ?-Sitosterol Cholesterol Glycerol 1-stearate Glycerol 1-(9-octadecenoate) * * ** ** ** *** * ** ** * * * * * * * * * * * * * * Glycerol 1-palmitate Glycerol 2-palmitate Behenic acid(C22:0) Arachidonic acid(C20:4) Arachidic acid(C20:0) Linoleic acid(C18:2) Oleic acid(C18:1) Stearic acid(C18:0) Margaric acid(C17:0) Palmitic acid(C16:0) Myristic acid(C14:0) ** * Lauric acid(C12:0) Uric acid * Phosphoric acid Inosine Amino acids Oleamide * 6 Vitamin C * * Adenosine monophosphate Adenosine Uridine Xanthine Hypoxanthine 1 Glucose myo-Inositol * * ** * * * * 4 Inositol monophosphate * Tyrosine Lysine Glutamine Phenylalanine 2 Methionine 3 Proline 5 * Fold Change Metabolic Profiling by GC/MS Lipids 0 Purine metabolism N DNA/RNA ATP N N N O NH2 NH2 N N N N N N AMP N ribose ribose ribose-P NH Adenosine Inosine O N Normal tissue De novo synthesis NH N Cancerous cells Salvage pathway N ribose-P IMP O O H N H2O2 NH O N H N H Uric acid H2O+O2 O Xanthine oxireductase N N H O NH N H Xanthine O H2O2 H2O+O2 Xanthine oxireductase N N H NH N Hypoxanthine Fold Change 0 -1 Carnitine -3 n = 26 *: p<0.001 Phospholipids Amides Polyps/Mucosa - 31 - 32 Docosahexaenoic acid (DHA, C22:6) Deoxycholic aicd Citramalic acid ** Fatty Acids Lipids Tumors/Mucosa = * Unknown, m/z=426.3 Eicosapentanoic acid (EPA, C20:5) * Arachidonic acid (C20:4) cis-11-Eicosenoic acid (C20:1) γ-Linolenic acid (C18:3) α-Linolenic acid (C18:3) Oleic acid (C18:1) Stearic acid (C18:0) Myristic acid (C14:0) Stearamide Oleamide Myristamide Carnitines Linoleic acid (C18:2) Palmitic acid (C16:0) LPC C16:0 * Palmitamide 1 LPC C20:4 * LPC C18:2 * LPC C18:1 * Glycerophosphocholine 4 LPC C18:0 3 Choline 2 Palmitoylcarnitine 5 Acetylcarnitine -2 Betaine Metabolic Profiling by LC/MS Others * Main Findings 1. 2. Three stages are rather different in metabolomes, although polyps and carcinoma show overlapping profiles. Increase in aa - provide reservoir for bioactivities. 3. Enhanced glucose consumption - switching to glycolytic pathways in cancerous tissues. 4. High concentrations of carnitines, FAs and other lipids requirements for biosynthesis of cell membrane of rapidly dividing cells. 5. Nucleotide purine salvage pathway – growth advantage. 6. Significant decrease of 2nd bile acid in carcinoma abnormal metabolic function for adaptation? CONCLUSION Metabolomics has promise in helping us dissect a metabolome. As a platform for biomarker discovery early days. Integrating genomic, proteomic and metabolomic data in a system approach will be interesting and challenging. Acknowledgements ONG Eng Shi, XU Fungguo, LIU Ying- EPH, NUS ZOU Li - SMART LI Shao Xia, GAO Yen Hong - China CDC CHEAH Peh Yean, EU Kong Weng - Colorectal Surgery Department, SGH Life Sciences Inst., NUS Centre for Environmental Health, YLLSOM, NUS. Singapore MIT Alliance on Research & Technology Department of Chemistry, NUS All patients participated in this study