Qing Hui Wu

Bio: Qing Hui Wu is an academic researcher from University Health System. The author has contributed to research in topics: Medicine & Bladder cancer. The author has an hindex of 4, co-authored 9 publications receiving 172 citations. Previous affiliations of Qing Hui Wu include National University of Singapore.

Noninvasive urinary metabonomic diagnosis of human bladder cancer.

Abstract: Cystoscopy is considered the gold standard for the clinical diagnosis of human bladder cancer (BC). As cystoscopy is expensive and invasive, it may compromise patients' compliance and account for the failure in detecting recurrent BC in some patients. In this paper, we investigated the role of urinary metabonomics in the diagnosis of human BC. Gas chromatography/time-of-flight mass spectrometry was applied for the urinary metabolic profiling of 24 BC patients and 51 non-BC controls. The acquired data were analyzed using multivariate principal component analysis followed by orthogonal partial least-squares discriminant analysis (OPLS-DA). Model validity was verified using permutation tests and receiver operating characteristic (ROC) analysis. BC patients were clearly distinguished from non-BC subjects based on their global urinary metabolic profiles (OPLS-DA, 4 latent variables, R(2)X = 0.420, R(2)Y = 0.912 and Q(2) (cumulative) = 0.245; ROC AUC of 0.90; 15 marker metabolites). One-hundred percent sensitivity in detecting BC was observed using urinary metabonomics versus 33% sensitivity achieved by urinary cytology. Additionally, urinary metabonomics exhibited potential in the staging and grading of bladder tumors. In summary, urinary metabonomics is amenable for the noninvasive diagnosis of human BC.

Tryptophan-kynurenine ratio as a biomarker of bladder cancer.

Abstract: Objectives To investigate plasma and urinary kynurenine (KYN)-tryptophan (TRP) ratios in bladder cancer, expression of indoleamine 2,3-dioxygenase 1 (IDO1) in relation to tryptophan 2,3-dioxygenase (TDO2) in bladder tumour, and the correlation of KYN-TRP ratio with bladder tumour burden. Methods Metabotyping of the TRP-KYN metabolic axis was performed via a clinical case-control study. Expression of IDO1 and TDO2 was measured in human biopsied tissues. Correlational experiments between KYN-TRP ratio and bladder tumour were performed using a murine orthotopic prostate-specific antigen (PSA)-secreting MB49 bladder cancer model. Results We established for the first time that plasma TRP level was significantly decreased, while both plasma and urinary KYN-TRP ratios were significantly higher in bladder cancer patients, and expression level of IDO1 but not TDO2 was increased in human bladder tumour. We reported the positive correlation between IDO1 expression, KYN-TRP ratio, normalized PSA to creatinine, and bladder tumour burden in the murine model. Conclusion Kynurenine-tryptophan ratio is a promising surveillance biomarker for bladder cancer, but would require further validation before clinical translation.

Gmcsf and Ifnα gene therapy improves the response to BCG immunotherapy in a murine model of bladder cancer.

Abstract: Aim: To develop a strategy to improve response to bacillus Calmette-Gueri (BCG) using cytokine gene therapy (Gmcsf + Ifnα). Materials & methods: MB49-PSA tumor-bearing C57BL/6N mice were assigned into four groups: control; Gmcsf + Ifnα therapy; BCG therapy or combined therapy (Gmcsf + Ifnα and BCG). In schedule 1, cytokine gene therapy was delivered before BCG therapy (eight instillations). In schedule 2, cytokine gene and BCG therapy were instilled alternatively (eight instillations). Tumors were analyzed by immunohistochemistry and mRNA analysis and urinary immune cells by flow cytometry. Results: Combined therapy in schedule 2 reduced tumor growth, increased immune cell recruitment and was associated with reduced inflammation when compared with BCG therapy. Conclusion: Alternating cytokine gene delivery with BCG therapy modulates the tumor environment increasing receptivity to BCG.

The Human Urine Metabolome

Abstract: Urine has long been a “favored” biofluid among metabolomics researchers. It is sterile, easy-to-obtain in large volumes, largely free from interfering proteins or lipids and chemically complex. However, this chemical complexity has also made urine a particularly difficult substrate to fully understand. As a biological waste material, urine typically contains metabolic breakdown products from a wide range of foods, drinks, drugs, environmental contaminants, endogenous waste metabolites and bacterial by-products. Many of these compounds are poorly characterized and poorly understood. In an effort to improve our understanding of this biofluid we have undertaken a comprehensive, quantitative, metabolome-wide characterization of human urine. This involved both computer-aided literature mining and comprehensive, quantitative experimental assessment/validation. The experimental portion employed NMR spectroscopy, gas chromatography mass spectrometry (GC-MS), direct flow injection mass spectrometry (DFI/LC-MS/MS), inductively coupled plasma mass spectrometry (ICP-MS) and high performance liquid chromatography (HPLC) experiments performed on multiple human urine samples. This multi-platform metabolomic analysis allowed us to identify 445 and quantify 378 unique urine metabolites or metabolite species. The different analytical platforms were able to identify (quantify) a total of: 209 (209) by NMR, 179 (85) by GC-MS, 127 (127) by DFI/LC-MS/MS, 40 (40) by ICP-MS and 10 (10) by HPLC. Our use of multiple metabolomics platforms and technologies allowed us to identify several previously unknown urine metabolites and to substantially enhance the level of metabolome coverage. It also allowed us to critically assess the relative strengths and weaknesses of different platforms or technologies. The literature review led to the identification and annotation of another 2206 urinary compounds and was used to help guide the subsequent experimental studies. An online database containing the complete set of 2651 confirmed human urine metabolite species, their structures (3079 in total), concentrations, related literature references and links to their known disease associations are freely available at http://www.urinemetabolome.ca.

Reversal of Tumoral Immune Resistance by Inhibition of Tryptophan 2,3-Dioxygenase (TDO): Design, Synthesis and Preclinical Evaluation of a Novel TDO Inhibitor.

Abstract: Tryptophan catabolism mediated by indoleamine 2,3-dioxygenase (IDO1) is an important mechanism of peripheral immune tolerance contributing to tumoral immune resistance, and IDO1 inhibition is an active area of drug development. Tryptophan 2,3-dioxygenase (TDO) is an unrelated hepatic enzyme that also degrades tryptophan along the kynurenine pathway. Here, we show that enzymatically active TDO is expressed in a significant proportion of human tumors. In a preclinical model, TDO expression by tumors prevented their rejection by immunized mice. We developed a TDO inhibitor, which, upon systemic treatment, restored the ability of mice to reject TDO-expressing tumors. Our results describe a mechanism of tumoral immune resistance based on TDO expression and establish proof-of-concept for the use of TDO inhibitors in cancer therapy.

Plasma Free Amino Acid Profiling of Five Types of Cancer Patients and Its Application for Early Detection

Abstract: Background Recently, rapid advances have been made in metabolomics-based, easy-to-use early cancer detection methods using blood samples Among metabolites, profiling of plasma free amino acids (PFAAs) is a promising approach because PFAAs link all organ systems and have important roles in metabolism Furthermore, PFAA profiles are known to be influenced by specific diseases, including cancers Therefore, the purpose of the present study was to determine the characteristics of the PFAA profiles in cancer patients and the possibility of using this information for early detection Methods and Findings Plasma samples were collected from approximately 200 patients from multiple institutes, each diagnosed with one of the following five types of cancer: lung, gastric, colorectal, breast, or prostate cancer Patients were compared to gender- and age- matched controls also used in this study The PFAA levels were measured using high-performance liquid chromatography (HPLC)–electrospray ionization (ESI)–mass spectrometry (MS) Univariate analysis revealed significant differences in the PFAA profiles between the controls and the patients with any of the five types of cancer listed above, even those with asymptomatic early-stage disease Furthermore, multivariate analysis clearly discriminated the cancer patients from the controls in terms of the area under the receiver-operator characteristics curve (AUC of ROC >075 for each cancer), regardless of cancer stage Because this study was designed as case-control study, further investigations, including model construction and validation using cohorts with larger sample sizes, are necessary to determine the usefulness of PFAA profiling Conclusions These findings suggest that PFAA profiling has great potential for improving cancer screening and diagnosis and understanding disease pathogenesis PFAA profiles can also be used to determine various disease diagnoses from a single blood sample, which involves a relatively simple plasma assay and imposes a lower physical burden on subjects when compared to existing screening methods

Global urinary metabolic profiling procedures using gas chromatography–mass spectrometry

Abstract: The role of urinary metabolic profiling in systems biology research is expanding. This is because of the use of this technology for clinical diagnostic and mechanistic studies and for the development of new personalized health care and molecular epidemiology (population) studies. The methodologies commonly used for metabolic profiling are NMR spectroscopy, liquid chromatography mass spectrometry (LC/MS) and gas chromatography-mass spectrometry (GC/MS). In this protocol, we describe urine collection and storage, GC/MS and data preprocessing methods, chemometric data analysis and urinary marker metabolite identification. Results obtained using GC/MS are complementary to NMR and LC/MS. Sample preparation for GC/MS analysis involves the depletion of urea via treatment with urease, protein precipitation with methanol, and trimethylsilyl derivatization. The protocol described here facilitates the metabolic profiling of ∼400-600 metabolites in 120 urine samples per week.

Mass spectrometric based approaches in urine metabolomics and biomarker discovery

Abstract: Urine metabolomics has recently emerged as a prominent field for the discovery of non-invasive biomarkers that can detect subtle metabolic discrepancies in response to a specific disease or therapeutic intervention. Urine, compared to other biofluids, is characterized by its ease of collection, richness in metabolites and its ability to reflect imbalances of all biochemical pathways within the body. Following urine collection for metabolomic analysis, samples must be immediately frozen to quench any biogenic and/or non-biogenic chemical reactions. According to the aim of the experiment; sample preparation can vary from simple procedures such as filtration to more specific extraction protocols such as liquid-liquid extraction. Due to the lack of comprehensive studies on urine metabolome stability, higher storage temperatures (i.e. 4°C) and repetitive freeze-thaw cycles should be avoided. To date, among all analytical techniques, mass spectrometry (MS) provides the best sensitivity, selectivity and identification capabilities to analyze the majority of the metabolite composition in the urine. Combined with the qualitative and quantitative capabilities of MS, and due to the continuous improvements in its related technologies (i.e. ultra high-performance liquid chromatography [UPLC] and hydrophilic interaction liquid chromatography [HILIC]), liquid chromatography (LC)-MS is unequivocally the most utilized and the most informative analytical tool employed in urine metabolomics. Furthermore, differential isotope tagging techniques has provided a solution to ion suppression from urine matrix thus allowing for quantitative analysis. In addition to LC-MS, other MS-based technologies have been utilized in urine metabolomics. These include direct injection (infusion)-MS, capillary electrophoresis-MS and gas chromatography-MS. In this article, the current progresses of different MS-based techniques in exploring the urine metabolome as well as the recent findings in providing potentially diagnostic urinary biomarkers are discussed. © 2015 Wiley Periodicals, Inc. Mass Spec Rev 36:115-134, 2017.