Global metabolomics profiling of colorectal cancer in Malaysian patients

The γ-glutamyl cycle serves as an amino acids supply system in colorectal cancer organoids under chronic hypoxia

Malignant tumors are characterized by a hypoxic microenvironment, and metabolic reprogramming is necessary to ensure energy production and oxidative stress resistance. Although the microenvironmental properties of tumors vary under acute and chronic hypoxia, studies on chronic hypoxia-induced metabolic changes are limited. In the present study, we performed a comprehensive metabolic analysis in a chronic hypoxia model using colorectal cancer (CRC) organoids, and identified an amino acid supply system through the γ-glutamyl cycle, a glutathione recycling pathway. We analyzed the metabolic changes caused by hypoxia over time and observed that chronic hypoxia resulted in an increase in 5-oxoproline and a decrease in oxidized glutathione (GSSG) compared to acute hypoxia. These findings suggest that chronic hypoxia induces metabolic changes in the γ-glutamyl cycle. Moreover, inhibition of the γ-glutamyl cycle via γ-glutamyl cyclotransferase (GGCT) and γ-glutamyl transferase 1 (GGT1) knockdown significantly reversed chronic hypoxia-induced upregulation of 5-oxoproline and several amino acids. Notably, GGT1 knockdown downregulated the intracellular levels of γ-glutamyl amino acids. Conclusively, these results indicate that the γ-glutamyl cycle serves as an amino acid supply system in CRC under chronic hypoxia, which provides fresh insight into cancer metabolism under chronic hypoxia.

Understanding exposomes and its relation with cancer risk in Malaysia based on epidemiological evidence: a narrative review

The prevalence of cancer is increasing globally, and Malaysia is no exception. The exposome represents a paradigm shift in cancer research, emphasizing the importance of a holistic approach that considers the cumulative effect of diverse exposures encountered throughout life. The exposures include dietary factors, air and water pollutants, occupational hazards, lifestyle choices, infectious agents and social determinants of health. The exposome concept acknowledges that each individual's cancer risk is shaped by not only their genetic makeup but also their unique life experiences and environmental interactions. This comprehensive review was conducted by systematically searching scientific databases such as PubMed, Scopus and Google Scholar, by using the keywords "exposomes (environmental exposures AND/OR physical exposures AND/OR chemical exposures) AND cancer risk AND Malaysia", for relevant articles published between 2010 and 2023. Articles addressing the relationship between exposomes and cancer risk in the Malaysian population were critically evaluated and summarized. This review aims to provide an update on the epidemiological evidence linking exposomes with cancer risk in Malaysia. This review will provide an update for current findings and research in Malaysia related to identified exposomes-omics interaction and gap in research area related to the subject matter. Understanding the interplay between complex exposomes and carcinogenesis holds the potential to unveil novel preventive strategies that may be beneficial for public health.

Serum Metabolomics of Retinoblastoma: Assessing the Differential Serum Metabolic Signatures of Unilateral and Bilateral Patients

Retinoblastoma (Rb) is the most common pediatric eye cancer. To identify the biomarkers for early diagnosis and monitoring the progression of Rb in patients, mapping of the alterations in their metabolic profiles is essential. The present study aims at exploring the metabolic disparity in serum from Rb patients and controls using NMR-based metabolomics. A total of 72 metabolites, including carbohydrates, amino acids, and organic acids, were quantified in serum samples from 24 Rb patients and 26 controls. Distinct clusters of Rb patients and controls were obtained using the partial least-squares discriminant analysis (PLS-DA) model. Further, univariate and multivariate analyses of unilateral and bilateral Rb patients with respect to their age-matched controls depicted their distinct metabolic fingerprints. Metabolites including 2-phosphoglycerate, 4-aminobutyrate, proline, O-phosphocholine, O-phosphoethanolamine, and Sn-glycero-3-phosphocholine (Sn-GPC) showed significant perturbation in both unilateral and bilateral Rb patients. However, metabolic differences among the bilateral Rb cases were more pronounced than those in unilateral Rb cases with respect to controls. In addition to major discriminatory metabolites for Rb, unilateral and bilateral Rb cases showed specific metabolic changes, which might be the result of their differential genetic/somatic mutational backgrounds. This further suggests that the aberrant metabolic perturbation in bilateral patients signifies the severity of the disease in Rb patients. The present study demonstrated that identified serum metabolites have potential to serve as a noninvasive method for detection of Rb, discriminate bilateral from unilateral Rb patients, and aid in better understanding of the RB tumor biology.

Impact of Sulfur Fumigation on the Chemistry of Dioscoreae Rhizoma (Chinese Yam)

Dioscoreae Rhizoma (Chinese yam; derived from the rhizome of Dioscorea opposita Thunb.) (DR), commonly consumed as a food or supplement, is often sulfur-fumigated during post-harvest handling, but it remains largely unknown if and how sulfur fumigation impacts the chemistry of DR. In this study, we report the impact of sulfur fumigation on the chemical profile of DR and then the molecular and cellular mechanisms potentially involved in the chemical variations induced by sulfur fumigation. The results show that sulfur fumigation significantly and specifically changed the small metabolites (molecular weight lower than 1000 Da) and polysaccharides of DR at both qualitative and quantitative levels. Multifaceted molecular and cellular mechanisms involving chemical transformations (e.g., acidic hydrolysis, sulfonation, and esterification) and histological damage were found to be responsible for the chemical variations in sulfur-fumigated DR (S-DR). The research outcomes provide a chemical basis for further comprehensive and in-depth safety and functional evaluations of sulfur-fumigated DR.

Increased ENT2 expression and its association with altered purine metabolism in cell lines derived from different stages of colorectal cancer

Colorectal cancer (CRC) is one of the most prevalent malignant cancer types worldwide. Although the purine metabolism pathway is vital for cancer cell survival, little is known about the role of equilibrative nucleoside transporter 2 (ENT2) in CRC development and its association with purine metabolites. The aim of the present study was to evaluate the levels of hypoxanthine phosphoribosyl transferase (HPRT), hypoxanthine and uric acid (UA), as well as xanthine oxidase (XO) activity, and investigate their association with ENT2 expression levels in a normal human colon cell line and CRC cell lines derived from different stages of CRC. These analyses were performed using the normal colon CCD-841CoN cell line and a panel of human CRC cell lines comprising SW480, HCT15 and HCT116, which represent Dukes' B, C and D stages, respectively. Reverse transcription-quantitative PCR was performed to determine the level of ENT2 mRNA expression. In cells of all CRC stages, the levels of HPRT and hypoxanthine were significantly higher (P<0.05), while XO activity and UA levels were significantly decreased (P<0.05), compared with those in the CCD-841CoN cell line. ENT2 expression was found to be elevated in cells derived from all stages of CRC. The Dukes' D stage cell line had higher levels of HPRT and hypoxanthine, although its ENT2 level was not significantly lower than that of the Dukes' B and C stage cell lines. Increased levels of HPRT and hypoxanthine in various stages of CRC may indicate an increase in the activity of the salvage pathway. The increased expression of ENT2 implies the importance of the ENT2 protein in facilitating hypoxanthine transport, which is required for enhanced DNA synthesis via hypoxanthine recycling. In conclusion, ENT2 may have potential as a target in the development of CRC therapeutics.

Two effective models based on comprehensive lipidomics and metabolomics can distinguish BC versus HCs, and TNBC versus non-TNBC

BACKGROUND

Lipidomics and metabolomics are closely related to tumor phenotypes, and serum lipoprotein subclasses and small-molecule metabolites are considered as promising biomarkers for breast cancer (BC) diagnosis. This study aimed to explore potential biomarker models based on lipidomic and metabolomic analysis that could distinguish BC from healthy controls (HCs) and triple-negative BC (TNBC) from non-TNBC.

METHODS

Blood samples were collected from 114 patients with BC and 75 HCs. A total of 112 types of lipoprotein subclasses and 30 types of small-molecule metabolites in the serum were detected by ¹ H-NMR. All lipoprotein subclasses and small-molecule metabolites were subjected to a three-step screening process in the order of significance (p < 0.05), univariate regression (p < 0.1), and lasso regression (nonzero coefficient). Discriminant models of BC versus HCs and TNBC versus non-TNBC were established using binary logistic regression.

RESULTS

We developed a valid discriminant model based on three-biomarker panel (formic acid, TPA2, and L6TG) that could distinguish patients with BC from HCs. The area under the receiver operating characteristic curve (AUC) was 0.999 (95% confidence interval [CI]: 0.995-1.000) and 0.990 (95% CI: 0.959-1.000) in the training and validation sets, respectively. Based on the panel (D-dimer, CA15-3, CEA, L5CH, glutamine, and ornithine), a discriminant model was established to differentiate between TNBC and non-TNBC, with AUC of 0.892 (95% CI: 0.778-0.967) and 0.905 (95% CI: 0.754-0.987) in the training and validation sets, respectively.

CONCLUSION

This study revealed lipidomic and metabolomic differences between BC versus HCs and TNBC versus non-TNBC. Two validated discriminatory models established against lipidomic and metabolomic differences can accurately distinguish BC from HCs and TNBC from non-TNBC.

IMPACT

Two validated discriminatory models can be used for early BC screening and help BC patients avoid time-consuming, expensive, and dangerous BC screening.

Comprehensive Review of Biomarkers for the Treatment of Locally Advanced Colon Cancer

Despite the implementation of global screening programs, colorectal cancer (CRC) remains the second leading cause of cancer-related deaths worldwide. More than 10% of patients with colon cancer are diagnosed as having locally advanced disease with a relatively poor five-year survival rate. Locally advanced colon cancer (LACC) presents surgical challenges to R0 resection. The advantages and disadvantages of preoperative radiotherapy for LACC remain undetermined. Although several reliable novel biomarkers have been proposed for the prediction and prognosis of CRC, few studies have focused solely on the treatment of LACC. This comprehensive review highlights the role of predictive biomarkers for treatment and postoperative oncological outcomes for patients with LACC. Moreover, this review discusses emerging needs and approaches for the discovery of biomarkers that can facilitate the development of new therapeutic targets and surveillance of patients with LACC.

Yusof NF, Mohd Yunos RI, Ishak M, Saidin S, Rose IM, Sagap I, Mazlan L, Mohd Azman ZA, Mazlan M, Ab Rahim S, Wan Ngah WZ, Nathan S, Hashim NAA, Mohamed-Hussein ZA, Jamal R. TCGA-My: A Systematic Repository for Systems Biology of Malaysian Colorectal Cancer

Colorectal cancer (CRC) ranks second among the most commonly occurring cancers in Malaysia, and unfortunately, its pathobiology remains unknown. CRC pathobiology can be understood in detail with the implementation of omics technology that is able to generate vast amounts of molecular data. The generation of omics data has introduced a new challenge for data organization. Therefore, a knowledge-based repository, namely TCGA-My, was developed to systematically store and organize CRC omics data for Malaysian patients. TCGA-My stores the genome and metabolome of Malaysian CRC patients. The genome and metabolome datasets were organized using a Python module, pandas. The variants and metabolites were first annotated with their biological information using gene ontologies (GOs) vocabulary. The TCGA-My relational database was then built using HeidiSQL PorTable 9.4.0.512, and Laravel was used to design the web interface. Currently, TCGA-My stores 1,517,841 variants, 23,695 genes, and 167,451 metabolites from the samples of 50 CRC patients. Data entries can be accessed via search and browse menus. TCGA-My aims to offer effective and systematic omics data management, allowing it to become the main resource for Malaysian CRC research, particularly in the context of biomarker identification for precision medicine.

Serum metabolomic profiling for patients with adenocarcinoma of the esophagogastric junction

INTRODUCTION

The incidence of adenocarcinoma in the esophagogastric junction (AEG) has increased in the recent years. AEG is reported to have a worse prognosis compared with tumor confined to the stomach (non-AEG). Although the metabolic changes of non-AEG have been investigated in extensive studies, little effort focused on the metabolic profiling of AEG serum.

OBJECTIVES

Here we report an untargeted gas chromatography-mass spectrometry (GC-MS) method to explore the abnormal metabolism underlying AEG.

METHODS

GC-MS-based untargeted metabolomics approach combined with multivariate statistical analyses were used to study the metabolic profiling of serum samples from AEG patients (n = 70), non-AEG patients (n = 70) and health controls (n = 71).

RESULTS

A novel serum metabolic profiling of 18 metabolites from patients of AEG and non-AEG was indicated, in comparison with health controls. Moreover, AEG and non-AEG were also well-classified with 9 distinguishing metabolites including hypoxanthine, alanine, proline, pyroglutamate, glycine, lactate, succinic acid, glutamate and kynurenine, which produced a discriminatory model with an area under the Receiver Operating Characteristic (ROC) curve of 0.852, suggesting a distinct metabolic signature of AEG. Importantly, lactate and glutamate disclosed outcome-prediction values by multivariate cox-proportional hazard model and Kaplan-Meier method based on follow-up information for 2-5 years.

CONCLUSION

This is the first metabolomics study to identify serum metabolic signature of AEG. The distinguishing metabolites show a promising application on clinical diagnose and outcome prediction, and allow us to unveil several key metabolic variations coexisting in AEG, which may aid to understand the underlying metabolic mechanisms.

Potential of blood-based biomarker approaches in endometrium and breast cancer: a case-control comparison study

Purpose

Endometrial carcinoma is the second most common gynecological malignancy. Until today lacking a screening tool. A blood-based biomarker could help address this need.

Methods

The expression levels of 30 acylcarnitines, 18 amino acids, 6 miRNAs, and 7 DNA methylation sites were measured in blood samples from 331 women (20 EC, 14 benign uterine lesions (benign), 140 breast cancers (BC), 157 controls). Areas under the ROC curves (AUC), sensitivity (sens.) and specificity (spec.) were computed to identify the variables best distinguishing.

Results

The best top ten markers for the four comparisons (cancer vs. cancer-free; EC vs. BC, EC vs. controls; EC vs. benign), were identified via AUC. Malonylcarnitine distinguished best patients with EC from controls (AUC: 0.827, sens. 80%, spec. 73.1%) or BC (AUC: 0.819, sens. 84.3%, spec. 80%) being most notable. Tryptophan best differentiated benign from EC (AUC: 0.846, sens. 70%, spec. 92.9%).

Conclusions

The levels of the analyzed blood markers yielded promising results in the detection of EC and warrant further evaluation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00404-022-06482-8.

Use of Omics Technologies for the Detection of Colorectal Cancer Biomarkers

Colorectal cancer (CRC) is one of the most frequently diagnosed cancers with high mortality rates, especially when detected at later stages. Early detection of CRC can substantially raise the 5-year survival rate of patients, and different efforts are being put into developing enhanced CRC screening programs. Currently, the faecal immunochemical test with a follow-up colonoscopy is being implemented for CRC screening. However, there is still a medical need to describe biomarkers that help with CRC detection and monitor CRC patients. The use of omics techniques holds promise to detect new biomarkers for CRC. In this review, we discuss the use of omics in different types of samples, including breath, urine, stool, blood, bowel lavage fluid, or tumour tissue, and highlight some of the biomarkers that have been recently described with omics data. Finally, we also review the use of extracellular vesicles as an improved and promising instrument for biomarker detection.

The analysis of metabolomics and transcriptomics data in head and neck squamous cell carcinoma

OBJECTIVE

Studies have shown that cancer progression of head and neck squamous cell carcinoma (HNSCC) is related with metabolic alterations. The aim of this study is to identify the clinical roles of metabolic alterations in HNSCC.

MATERIALS AND METHODS

Metabolism-related genes associated with HNSCC were searched in public databases. A predictive and efficacious LASSO model was fabricated to optimize the diagnosis that was based on these genes. Meantime, Ultra-Performance Liquid Chromatography-Quadrupole/Orbitrap High Resolution Mass Spectrometry (UHPLC-Q-Orbitrap HRMS) was used to compare patients with HNSCC (n=73) with healthy controls (HC) (n=51) for serum metabolites. Potential biomarkers and alterations in serum metabolites were analysed and evaluated using t-test analysis, principal component analysis and orthogonal partial least square discrimination analysis (OPLS-DA).

RESULTS

Overall, 21 differential metabolites were probed in serum, of which 8 metabolites had potential for clinical uses. Transcriptome analysis showed that 4 genes in the constructed LASSO model were found to be associated with 7 differential metabolites. Metabolic pathway analysis by MetaboAnalyst showed that the biomarkers that were related with HNSCC were closely related to 4 metabolism pathways (p<0.05).

CONCLUSION

To conclude, future research on HNSCC should be directed toward multi-omics to provide treatment, intervention, or diagnosis of the disease.

Gut Dysbiosis and Intestinal Barrier Dysfunction: Potential Explanation for Early-Onset Colorectal Cancer

Colorectal cancer (CRC) is a heterogeneous disease that commonly affects individuals aged more than 50 years old globally. Regular colorectal screening, which is recommended for individuals aged 50 and above, has decreased the number of cancer death toll over the years. However, CRC incidence has increased among younger population (below 50 years old). Environmental factors, such as smoking, dietary factor, urbanization, sedentary lifestyle, and obesity, may contribute to the rising trend of early-onset colorectal cancer (EOCRC) because of the lack of genetic susceptibility. Research has focused on the role of gut microbiota and its interaction with epithelial barrier genes in sporadic CRC. Population with increased consumption of grain and vegetables showed high abundance of Prevotella, which reduces the risk of CRC. Microbes, such as Fusobacterium nucleatum, Bacteroides fragilis and Escherichia coli deteriorate in the intestinal barrier, which leads to the infiltration of inflammatory mediators and chemokines. Gut dysbiosis may also occur following inflammation as clearly observed in animal model. Both gut dysbiosis pre- or post-inflammatory process may cause major alteration in the morphology and functional properties of the gut tissue and explain the pathological outcome of EOCRC. The precise mechanism of disease progression from an early stage until cancer establishment is not fully understood. We hypothesized that gut dysbiosis, which may be influenced by environmental factors, may induce changes in the genome, metabolome, and immunome that could destruct the intestinal barrier function. Also, the possible underlying inflammation may give impact microbial community leading to disruption of physical and functional role of intestinal barrier. This review explains the potential role of the interaction among host factors, gut microenvironment, and gut microbiota, which may provide an answer to EOCRC.