Serum leucine-rich alpha-2-glycoprotein-1 with fucosylated triantennary N-glycan: a novel colorectal cancer marker

High serum levels of leucine-rich α-2 glycoprotein 1 (LRG-1) are associated with poor survival in patients with early breast cancer

BACKGROUND

Leucine-rich α-2 glycoprotein 1 (LRG-1) is a secreted glycoprotein that is mainly produced in the liver. Elevated levels of LRG-1 are found in a multitude of pathological conditions including eye diseases, diabetes, infections, autoimmune diseases, and cancer. In patients with early breast cancer (BC), high intratumoral LRG-1 protein expression levels are associated with reduced survival. In this study, we assessed serum levels of LRG-1 in patients with early BC and investigated its correlation with the presence of disseminated tumor cells (DTCs) in the bone marrow and survival outcomes.

METHODS

Serum LRG-1 levels of 509 BC patients were determined using ELISA and DTCs were assessed by immunocytochemistry using the pan-cytokeratin antibody A45-B/B3. We stratified LRG-1 levels according to selected clinical parameters. Using the log-rank (Mantel-Cox) test and multivariate Cox regression analysis, Kaplan-Meier survival curves and prognostic relevance were assessed.

RESULTS

Mean serum levels of LRG-1 were 29.70 ± 8.67 µg/ml. Age was positively correlated with LRG-1 expression (r = 0.19; p < 0.0001) and significantly higher LRG-1 levels were found in patients over 60 years compared to younger ones (30.49 ± 8.63 µg/ml vs. 28.85 ± 8.63 µg/ml; p = 0.011) and in postmenopausal patients compared to premenopausal patients (30.15 ± 8.34 µg/ml vs. 26.936.94 µg/ml; p = 0.002). Patients with no DTCs showed significantly elevated LRG-1 levels compared to the DTC-positive group (30.51 ± 8.69 µg/ml vs. 28.51 ± 8.54 µg/ml; p = 0.004). Overall and BC-specific survival was significantly lower in patients with high serum LRG-1 levels (above a cut-off of 33.63 µg/ml) compared to patients with lower LRG-1 levels during a mean follow-up of 8.5 years (24.8% vs. 11.1% BC-specific death; p = 0.0003; odds ratio 2.63, 95%CI: 1.56-4.36). Multivariate analyses revealed that LRG-1 is an independent prognostic marker for BC-specific survival (p = 0.001; hazard ratio 2.61).

CONCLUSIONS

This study highlights the potential of LRG-1 as an independent prognostic biomarker in patients with early BC.

The evaluation of salivary leucine-rich alpha-2 glycoprotein (LRG) and C-reactive protein (CRP) in humans with periodontal health or periodontal disease

OBJECTIVE

The purpose of the present research is to evaluate the salivary levels of leucine-rich alpha-2 glycoprotein (LRG) and C-reactive protein (CRP) in periodontal health and disease (gingivitis and stage III periodontitis) and also to compare the discriminative efficiencies of both biomarkers in periodontal disease.

BACKGROUND

LRG is a new acute-phase protein whose functions are still being investigated. LRG and CRP are both biomarkers that are increased by inflammation. No clinical study has yet investigated the comparison of the level of LRG and CRP in periodontal health, gingivitis and periodontitis in saliva samples.

METHODS

A total of 60 individuals, including 20 periodontally healthy (control group/group C), 20 with gingivitis (group G), and 20 with Stage III periodontitis (group P), who were systemically healthy and non-smokers, participated in this study. Periodontal charts were used for recording clinical periodontal parameters and saliva LRG and CRP levels were measured by ELISA. Analyzing the area under the curve (AUC) was performed by the receiver-operating characteristics curve.

RESULTS

Salivary levels of LRG and CRP were significantly higher in disease groups than in group C (p < .05). Positive statistically significant correlations were observed between both biomarkers and clinical parameters (p < .05). There was also a strong positive correlation between two biomarkers (p < .05). In distinguishing periodontal disease from periodontal health, LRG (AUC = 0.833) and CRP (AUC = 0.826) were found to have similar accuracy (p = .923).

CONCLUSION

LRG and CRP may be useful and similarly effective biomarkers in the diagnosis of periodontal diseases based on the findings of this study.

Serum-based Comprehensive N-Glycans Profiling Analysis in Different Gastric Disease Stages by Porous Graphitic Carbon Liquid Chromatography-Mass Spectrometry Associated With Potential Marker Discovery

BACKGROUND/AIM

N-glycans are potential serum biomarkers due to their aberrant structure and abundance alteration during disease progression. Few studies have been associated with relative quantitative N-glycans profiling during different gastric disease stages. In this study, we conducted an investigation on the profiling of N-glycans in patients with gastric disease, as well as in healthy controls.

MATERIALS AND METHODS

In this study, the porous graphitization carbon chromatography-high resolution Fourier transform mass spectrometry (PGC-FTMS) method was applied to assess comprehensive N-glycans profiling in patients at different stages of gastric disease, including gastritis, atrophic gastritis, gastric ulcer, gastric polyps, and gastric cancer.

RESULTS

A total of 45 N-glycans (relative abundance >0.1%) were detected, and 9 N-glycans were found to be potential biomarkers for gastric disease detection. Along with the progression of gastric disease, the abundance of sialylated N-glycans increased, while that of core-fucosylated N-glycans decreased. Multivariate statistical analysis demonstrated that N-glycans profiling between gastritis and healthy controls had significant differences. The characteristic N-glycans distinguished gastric cancer from healthy controls, which had strong clinical diagnostic value.

CONCLUSION

The relative quantitative profile of N-glycans in different gastric disease stages was revealed and serum N-glycans are proposed for distinguishing gastric disease stages in clinical application.

Glycoproteomics-based liquid biopsy: translational outlook for colorectal cancer clinical management in Southeast Asia

Colorectal cancer (CRC) signifies a significant healthcare challenge in Southeast Asia. Despite advancements in screening approaches and treatment modalities, significant medical gaps remain, ranging from prevention and early diagnosis to determining targeted therapy and establishing personalized approaches to managing CRC. There is a need to expand more validated biomarkers in clinical practice. An advanced technique incorporating high-throughput mass spectrometry as a liquid biopsy to unravel a repertoire of glycoproteins and glycans would potentially drive the development of clinical tools for CRC screening, diagnosis and monitoring, and it can be further adapted to the existing standard-of-care procedure. Therefore this review offers a perspective on glycoproteomics-driven liquid biopsy and its potential integration into the clinical care of CRC in the southeast Asia region.

Crystal structure of LRG1 and the functional significance of LRG1 glycan for LPHN2 activation

The serum glycoprotein leucine-rich ɑ-2-glycoprotein 1 (LRG1), primarily produced by hepatocytes and neutrophils, is a multifunctional protein that modulates various signaling cascades, mainly TGFβ signaling. Serum LRG1 and neutrophil-derived LRG1 have different molecular weights due to differences in glycosylation, but the impact of the differential glycan composition in LRG1 on its cellular function is largely unknown. We previously reported that LRG1 can promote both angiogenic and neurotrophic processes under hyperglycemic conditions by interacting with LPHN2. Here, we determined the crystal structure of LRG1, identifying the horseshoe-like solenoid structure of LRG1 and its four N-glycosylation sites. In addition, our biochemical and cell-biological analyses found that the deglycosylation of LRG1, particularly the removal of glycans on N325, is critical for the high-affinity binding of LRG1 to LPHN2 and thus promotes LRG1/LPHN2-mediated angiogenic and neurotrophic processes in mouse tissue explants, even under normal glucose conditions. Moreover, the intracavernous administration of deglycosylated LRG1 in a diabetic mouse model ameliorated vascular and neurological abnormalities and restored erectile function. Collectively, these data indicate a novel role of LRG1 glycans as molecular switches that can tune the range of LRG1's cellular functions, particularly the LRG1/LPHN2 signaling axis.

Accuracy of Serum Leucine-Rich Alpha-2 Glycoprotein in Evaluating Endoscopic Disease Activity in Crohn's Disease

BACKGROUND

Mucosal healing, confirmed by endoscopic evaluation, is the long-term goal of treatment for Crohn's disease (CD). Leucine-rich alpha-2 glycoprotein (LRG) is a new serum biomarker correlated with disease activity in inflammatory bowel disease. However, studies evaluating its relationship with CD, particularly in the context of small intestinal lesions, are scarce. The aim of this study was to investigate the accuracy of LRG in assessing endoscopic activity, especially remission, in patients with CD.

METHODS

Between July 2020 and March 2021, 72 patients with CD who underwent LRG testing and double-balloon endoscopy at the same time were included. Endoscopic activity was evaluated using the applied Simple Endoscopic Score for Crohn's disease, including small intestine lesions. The relationship of LRG with clinical symptoms and endoscopic activity was assessed, and its predictive accuracy was evaluated.

RESULTS

Leucine-rich alpha-2 glycoprotein showed a significant positive correlation with endoscopic activity (r = 0.619, P < .001), even in patients with active lesions in the small intestine (r = 0.626, P < .001). Multivariate logistic regression revealed that LRG was the only factor associated with endoscopic remission. An LRG cutoff value of 8.9 μg/mL had a sensitivity of 93.3%; specificity of 83.3%; positive predictive value of 96.6%; negative predictive value of 71.4%; accuracy of 91.7%; and area under the curve of 0.904 for the prediction of endoscopic remission.

CONCLUSIONS

Leucine-rich alpha-2 glycoprotein can be used in assessing endoscopic activity and is a reliable marker of endoscopic remission in CD patients. It can be an intermediate target in the treatment of CD.

Positioning and Usefulness of Biomarkers in Inflammatory Bowel Disease

BACKGROUND

Mucosal healing (MH) was proposed to be an ideal treatment goal for patients with inflammatory bowel disease (IBD). Instead of endoscopy to confirm MH, biomarkers are frequently used and have become an indispensable modality for the clinical examination of patients with IBD.

SUMMARY

Common biomarkers of IBD include C-reactive protein (CRP), erythrocyte sedimentation rate, antineutrophil cytoplasmic antibodies, anti-Saccharomyces cerevisiae antibodies, leucine-rich α2 glycoprotein, fecal calprotectin (FCP), and the fecal immunochemical test. Biomarkers play five major roles in the management of IBD: (1) diagnosing and distinguishing between IBD and non-IBD or ulcerative colitis and Crohn's disease; (2) predicting treatment response, especially before administrating biologics; (3) monitoring and grasping endoscopic or histological disease activity; (4) replacing endoscopy for diagnosing MH, including endoscopic and histological remission; and (5) predicting recurrence before disease activity appears through symptoms. Many reports have demonstrated the usefulness of CRP and FCP for those five roles; however, they have limitations for diagnosing MH or predicting treatment response. In general, FCP has better ability in those positions than CRP; additionally, leucine-rich α2 glycoprotein can diagnose endoscopic disease activity better than CRP. The novel biomarker, prostaglandin E-major urinary metabolite, and anti-αvβ6 antibody are expected to be noninvasive and reliable biomarkers; however, more evidence is required for future studies. Oncostatin M and microRNA are also prospects, in addition to other familiar and novel biomarkers.

KEY MESSAGES

Each biomarker has a useful feature; therefore, we should consider their features and use appropriate biomarkers for the five roles to enable noninvasive and smooth management of IBD.

A new method for screening acute/chronic lymphocytic leukemia: dual-label time-resolved fluorescence immunoassay

Background

Lymphocytic leukemia (LL) is a primary malignant tumor of hematopoietic tissue, which seriously affects the health of children and the elderly. The study aims to establish a new detection method for screening acute/chronic LL using time-resolved fluorescence immunoassay (TRFIA) via quantitative detection of S100 calcium binding protein A8 (S100A8) and leucine-rich alpha-2-glycoprotein 1 (LRG1) in serum.

Methods

Here a sandwich TRFIA was optimized and established: Anti-S100A8/LRG1 caputre antibodies immobilized on 96-well plates captured S100A8/LRG1, and then banded together with the anti-S100A8/LRG1 detection antibodies labeled with Europium(III) (Eu³⁺)/samarium(III) (Sm³⁺) chelates. Finally time resolved fluorometry measured the fluorescence intensity.

Results

The sensitivity of S100A8 was 1.15 ng/mL(LogY = 3.4027 + 0.4091 × LogX, R² = 0.9828, P < 0.001, dynamic range: 2.1–10,000 ng/mL), and 3.2 ng/mL for LRG1 (LogY = 3.3009 + 0.4082 × LogX, R² = 0.9748, P < 0.001, dynamic range: 4.0–10,000 ng/mL). The intra-assay and inter-assay CVs were low, ranging from 5.75% to 8.23% for S100A8 and 5.30% to 9.45% for LRG1 with high specificity and affinity in serum samples. Bland–Altman plots indicated TRFIA and ELISA kits have good agreement in clinical serum samples. Additionally, the cutoff values for S100A8 and LRG1 were 1849.18 ng/mL and 588.08 ng/mL, respectively.

Conclusion

The present TRFIA method could be used for the quantitative detection of S100A8 and LRG1 in serum, and it has high sensitivity, accuracy and specificity. Clinically, this TRFIA method could be suitable for screening of LL via the quantitative detection of S100A8 and LRG1.

Angiopathic activity of LRG1 is induced by the IL-6/STAT3 pathway

Leucine-rich α-2-glycoprotein 1 (LRG1) is a secreted glycoprotein that under physiological conditions is produced predominantly by the liver. In disease, its local induction promotes pathogenic neovascularisation while its inhibition leads to reduced dysfunctional angiogenesis. Here we examine the role of interleukin-6 (IL-6) in defective angiogenesis mediated by LRG1. IL-6 treatment induced LRG1 expression in endothelial cells and ex vivo angiogenesis cultures and promoted vascular growth with reduced mural cell coverage. In Lrg1^−/− explants, however, IL-6 failed to stimulate angiogenesis and vessels exhibited improved mural cell coverage. IL-6 activated LRG1 transcription through the phosphorylation and binding of STAT3 to a conserved consensus site in the LRG1 promoter, the deletion of which abolished activation. Blocking IL-6 signalling in human lung endothelial cells, using the anti-IL6 receptor antibody Tocilizumab, significantly reduced LRG1 expression. Our data demonstrate that IL-6, through STAT3 phosphorylation, activates LRG1 transcription resulting in vascular destabilisation. This observation is especially timely in light of the potential role of IL-6 in COVID-19 patients with severe pulmonary microvascular complications, where targeting IL-6 has been beneficial. However, our data suggest that a therapy directed towards blocking the downstream angiopathic effector molecule LRG1 may be of greater utility.

Research Progress on Leucine-Rich Alpha-2 Glycoprotein 1: A Review

Leucine-rich alpha⁃2 glycoprotein 1 (LRG1) is an important member of the leucine-rich repetitive sequence protein family. LRG1 was mainly involved in normal physiological activities of the nervous system, such as synapse formation, synapse growth, the development of nerve processes, neurotransmitter transfer and release, and cell adhesion molecules or ligand-binding proteins. Also, LRG1 affected the development of respiratory diseases, hematological diseases, endocrine diseases, tumor diseases, eye diseases, cardiovascular diseases, rheumatic immune diseases, infectious diseases, etc. LRG1 was a newly discovered important upstream signaling molecule of transforming growth factor⁃β (TGF⁃β) that affected various pathological processes through the TGF⁃β signaling pathway. However, research on LRG1 and its involvement in the occurrence and development of diseases was still in its infancy and the current studies were mainly focused on proteomic detection and basic animal experimental reports. We could reasonably predict that LRG1 might act as a new direction and strategy for the treatment of many diseases.

LRG1: an emerging player in disease pathogenesis

The secreted glycoprotein leucine-rich α-2 glycoprotein 1 (LRG1) was first described as a key player in pathogenic ocular neovascularization almost a decade ago. Since then, an increasing number of publications have reported the involvement of LRG1 in multiple human conditions including cancer, diabetes, cardiovascular disease, neurological disease, and inflammatory disorders. The purpose of this review is to provide, for the first time, a comprehensive overview of the LRG1 literature considering its role in health and disease. Although LRG1 is constitutively expressed by hepatocytes and neutrophils, Lrg1-/- mice show no overt phenotypic abnormality suggesting that LRG1 is essentially redundant in development and homeostasis. However, emerging data are challenging this view by suggesting a novel role for LRG1 in innate immunity and preservation of tissue integrity. While our understanding of beneficial LRG1 functions in physiology remains limited, a consistent body of evidence shows that, in response to various inflammatory stimuli, LRG1 expression is induced and directly contributes to disease pathogenesis. Its potential role as a biomarker for the diagnosis, prognosis and monitoring of multiple conditions is widely discussed while dissecting the mechanisms underlying LRG1 pathogenic functions. Emphasis is given to the role that LRG1 plays as a vasculopathic factor where it disrupts the cellular interactions normally required for the formation and maintenance of mature vessels, thereby indirectly contributing to the establishment of a highly hypoxic and immunosuppressive microenvironment. In addition, LRG1 has also been reported to affect other cell types (including epithelial, immune, mesenchymal and cancer cells) mostly by modulating the TGFβ signalling pathway in a context-dependent manner. Crucially, animal studies have shown that LRG1 inhibition, through gene deletion or a function-blocking antibody, is sufficient to attenuate disease progression. In view of this, and taking into consideration its role as an upstream modifier of TGFβ signalling, LRG1 is suggested as a potentially important therapeutic target. While further investigations are needed to fill gaps in our current understanding of LRG1 function, the studies reviewed here confirm LRG1 as a pleiotropic and pathogenic signalling molecule providing a strong rationale for its use in the clinic as a biomarker and therapeutic target.

The role of leucine-rich alpha-2-glycoprotein-1 in proliferation, migration, and invasion of tumors

BACKGROUND

Leucine-rich alpha-2-glycoprotein-1 (LRG1) is widely involved in proliferation, migration, and invasion of various tumor cells. Recent studies have evaluated the potential of LRG1 as both an early tumor and a prognostic biomarker.

METHOD

The relevant literature from PubMed is reviewed in this article.

RESULTS

It has been found that LRG1 mainly acts on the regulatory mechanisms of angiogenesis, epithelial-mesenchymal transition (EMT), and apoptosis by transforming growth factor (TGF-β) signaling pathway as well as affecting the occurrence and development of the tumors. Moreover, with advancement of research, LRG1 regulation pathways which are independent of TGF-β signaling pathway have been gradually revealed in different tumor cells; There are several studies on the biological effects of LRG1 as an inflammatory factor, vascular growth regulator, cell adhesion, and a cell viability influencing factor. In addition, various tumor suppression methods which are based on regulation of LRG1 levels have also shown high potential clinical value.

CONCLUSIONS

LRG1 are critical for the processes of tumorigenesis, development, and metastasis in various tumors. The present study reviewed the latest research on the achievements of LRG1 in tumor genesis and development. Further, this study also discussed the related molecular mechanisms of various biological functions of LRG1.

Role of Biomarkers in the Diagnosis and Treatment of Inflammatory Bowel Disease

The number of patients with inflammatory bowel disease (IBD) is increasing worldwide. Endoscopy is the gold standard to assess the condition of IBD. The problem with this procedure is that the burden and cost on the patient are high. Therefore, the identification of a reliable biomarker to replace endoscopy is desired. Biomarkers are used in various situations such as diagnosis of IBD, evaluation of disease activity, prediction of therapeutic effect, and prediction of relapse. C-reactive protein and fecal calprotectin have a lot of evidence as objective biomarkers of disease activity in IBD. The usefulness of the fecal immunochemical test, serum leucine-rich glycoprotein, and urinary prostaglandin E major metabolite have also been reported. Herein, we comprehensively review the usefulness and limitations of biomarkers that can be used in daily clinical practice regarding IBD. To date, no biomarker is sufficiently accurate to replace endoscopy; however, it is important to understand the characteristics of each biomarker and use the appropriate biomarker at the right time in daily clinical practice.

Identification of Whole-Serum Glycobiomarkers for Colorectal Carcinoma Using Reverse-Phase Lectin Microarray

Colorectal cancer (CRC) is one of the most common types of cancer among men and women worldwide. Efforts are currently underway to find novel and more cancer-specific biomarkers that could be detected in a non-invasive way. The analysis of aberrant glycosylation of serum glycoproteins is a way to discover novel diagnostic and prognostic CRC biomarkers. The present study investigated a whole-serum glycome with a panel of 16 different lectins in search for age-independent and CRC-specific glycomarkers using receiver operating characteristic (ROC) curve analyses and glycan heat matrices. Glycosylation changes present in the whole serum were identified, which could lead to the discovery of novel biomarkers for CRC diagnostics. In particular, the change in the bisecting glycans (recognized by Phaseolus vulgaris erythroagglutinin) had the highest discrimination potential for CRC diagnostics in combination with human L selectin providing area under the ROC curve (AUC) of 0.989 (95% CI 0.950-1.000), specificity of 1.000, sensitivity of 0.900, and accuracy of 0.960. We also implemented novel tools for identification of lectins with strong discrimination power.

Serum exosome-derived biomarkers for the early detection of oral squamous cell carcinoma

Blood exosomes help regulate communication between tumour cells, moderating their behaviour. We sought to determine the protein content in serum exosomes (SEs), to characterise SEs, and to discover novel clinical biomarkers of oral squamous cell carcinoma (OSCC). Differentially expressed proteins (DEPs) of OSCC were identified using proteomics and then analysed using bioinformatics, before validation using ELISA, IHC, and RT-PCR. The influence of SEs on oral cancer cells was detected using CCK-8 and migration assays. Twelve DEPs were found in SEs from OSCC. Four proteins were targeted for further verification. New biomarkers exhibiting high sensitivity and specificity in diagnosing OSCC comprised C-reactive protein (CRP), von willebrand factor (VWF), and leucine-rich alpha-2-glycoprotein (LRG). Combined biomarkers outperformed any single protein. We also demonstrated that tumour-derived exosomes promoted tumour cell migration, but not proliferation and apoptosis. Our study indicates that CRP, VWF, and LRG are potential clinically relevant OSCC biomarkers. OSCC-related SEs may help promote migration of oral cells.

Temporal multi-omics identifies LRG1 as a vascular niche instructor of metastasis

Metastasis is the primary cause of cancer-related mortality. Tumor cell interactions with cells of the vessel wall are decisive and potentially rate-limiting for metastasis. The molecular nature of this cross-talk is, beyond candidate gene approaches, hitherto poorly understood. Using endothelial cell (EC) bulk and single-cell transcriptomics in combination with serum proteomics, we traced the evolution of the metastatic vascular niche in surgical models of lung metastasis. Temporal multiomics revealed that primary tumors systemically reprogram the body’s vascular endothelium to perturb homeostasis and to precondition the vascular niche for metastatic growth. The vasculature with its enormous surface thereby serves as amplifier of tumor-induced instructive signals. Comparative analysis of lung EC gene expression and secretome identified the transforming growth factor–β (TGFβ) pathway specifier LRG1, leucine-rich alpha-2-glycoprotein 1, as an early instructor of metastasis. In the presence of a primary tumor, ECs systemically up-regulated LRG1 in a signal transducer and activator of transcription 3 (STAT3)–dependent manner. A meta-analysis of retrospective clinical studies revealed a corresponding up-regulation of LRG1 concentrations in the serum of patients with cancer. Functionally, systemic up-regulation of LRG1 promoted metastasis in mice by increasing the number of prometastatic neural/glial antigen 2 (NG2)+ perivascular cells. In turn, genetic deletion of Lrg1 hampered growth of lung metastasis. Postsurgical adjuvant administration of an LRG1-neutralizing antibody delayed metastatic growth and increased overall survival. This study has established a systems map of early primary tumor-induced vascular changes and identified LRG1 as a therapeutic target for metastasis.

The Prognostic Value of Leucine-Rich α2 Glycoprotein 1 in Pediatric Spinal Cord Injury

Objective

Leucine-rich α2 glycoprotein 1 (LRG1) is a novel cytokine, which is believed to be involved in the inflammatory process of a series of diseases. However, the relationship between LRG1 and spinal cord injury (SCI) has not been reported. The purpose of our study is to determine the predictive value of LRG1 for the prognosis of pediatric SCI (PSCI).

Methods

This study recruited 64 patients with confirmed PSCI and 40 healthy controls at Foshan Traditional Chinese Medicine Hospital from January 2016 to December 2020. The clinical information of all participants at the time of admission was recorded. Peripheral blood was collected, and commercial reagents were used to detect the level of serum LRG1. At the same time, the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) was used to assess the severity of PSCI.

Results

All participants were divided into PSCI group (n = 64) and NC group (n = 40). There was no significant difference in clinical information (age, gender, heart rate, systolic blood pressure, diastolic blood pressure, sampling time from injury, white blood cells, and C-reactive protein) between the two groups (p > 0.05). According to the interquartile range of serum LRG1, we compared the motor and sensory scores of ISNCSCI and found that serum LRG1 levels were negatively correlated with the prognosis of PSCI patients (p < 0.001). The results of receiver operating curve (ROC) showed that the sensitivity, specificity, and AUC (Area Under the Curve) of serum LRG1 level in predicting the prognosis of PSCI were 68.4%, 69.1%, and 0.705, respectively. The cut-off value of serum LRG1 level predicting the prognosis of PSCI is 21.1 μg/ml.

Conclusions

Serum LRG1 level is significantly increased in PSCI patients, and the elevated LRG1 level is negatively correlated with the prognosis of PSCI patients. Serum LRG1 may be a potentially useful biomarker for predicting PSCI.

Identification of Fucosylated SERPINA1 as a Novel Plasma Marker for Pancreatic Cancer Using Lectin Affinity Capture Coupled with iTRAQ-Based Quantitative Glycoproteomics

Pancreatic cancer (PC) is an aggressive cancer with a high mortality rate, necessitating the development of effective diagnostic, prognostic and predictive biomarkers for disease management. Aberrantly fucosylated proteins in PC are considered a valuable resource of clinically useful biomarkers. The main objective of the present study was to identify novel plasma glycobiomarkers of PC using the iTRAQ quantitative proteomics approach coupled with Aleuria aurantia lectin (AAL)-based glycopeptide enrichment and isotope-coded glycosylation site-specific tagging, with a view to analyzing the glycoproteome profiles of plasma samples from patients with non-metastatic and metastatic PC and gallstones (GS). As a result, 22 glycopeptides with significantly elevated levels in plasma samples of PC were identified. Fucosylated SERPINA1 (fuco-SERPINA1) was selected for further validation in 121 plasma samples (50 GS and 71 PC) using an AAL-based reverse lectin ELISA technique developed in-house. Our analyses revealed significantly higher plasma levels of fuco-SERPINA1 in PC than GS subjects (310.7 ng/mL v.s. 153.6 ng/mL, p = 0.0114). Elevated fuco-SERPINA1 levels were associated with higher TNM stage (p = 0.024) and poorer prognosis for overall survival (log-rank test, p = 0.0083). The increased plasma fuco-SERPINA1 levels support the utility of this protein as a novel prognosticator for PC.

Evaluation of Serum Leucine-Rich Alpha-2 Glycoprotein as a New Inflammatory Biomarker of Inflammatory Bowel Disease

Studies on serum leucine-rich alpha-2 glycoprotein (LRG) in inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), are scarce; the methods for estimating disease activity are less established, particularly for CD. This study is aimed at evaluating the utility of serum LRG as a potential inflammatory marker for IBD and to investigate the LRG gene expression in peripheral blood mononuclear cells (PBMCs) as a possible source of serum LRG. Overall, 98 patients with UC and 96 patients with CD were prospectively enrolled and clinically evaluated; 92 age-matched individuals served as the healthy controls. The blood samples were analyzed for serum LRG levels and routine laboratory parameters. Disease activity was assessed clinically and endoscopically. Finally, LRG gene expression in the PBMCs from a different cohort (41 patients with UC, 34 patients with CD, and 30 healthy controls) was examined. The serum LRG levels were higher during active disease than during inactive disease; additionally, serum LRG levels were positively correlated with clinical disease activity, C-reactive protein (CRP) levels, and other laboratory parameters in patients with UC and CD and with endoscopic disease activity in UC. UC and CD showed comparable areas under the curve (AUC) values for determining clinical remission and differentiating between endoscopic remission associated with LRG and CRP. The levels of LRG mRNA were also increased in PBMCs from patients with UC and CD and reflected disease activity. These data suggest that serum LRG, originated partially from PBMCs, is an inflammatory marker in UC and CD. A large-scale well-designed study should be conducted in the future to more accurately reveal the clinical significance of LRG in patients with IBD.

Diagnostic performances of leucine-rich α-2-glycoprotein 1 and stem cell factor for diagnosis and follow-up of colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is one of the most frequently diagnosed tumors worldwide with high mortality and morbidity. There is an urgent need for biomarkers to improve the outcomes and early detection of CRC. The sensitivity of traditional CRC tumor markers (carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9)) is not ideal. The levels of leucine-rich-alpha-2-glycoprotein 1 (LRG1) and stem cell factor (SCF) were evaluated, but the combined value of both markers is unclear. This case-control study included four groups: CRC patients before treatments (n = 22), CRC patients after treatments (n = 26), 20 patients with benign tumor, and 20 healthy subjects. Levels of routine biochemical and hematological markers, traditional tumor markers (CA19.9 and CEA), and candidate markers (LRG1 and SCF) were determined. Univariate and multivariate logistic regression analysis and area receiver-operating characteristic analysis (ROC) were used for evaluation the diagnostic performances of single and combined markers.

RESULTS

No significance difference in traditional tumor markers CEA, CA 19.9, and neutrophil-lymphocyte ratio (NLR) were found among study groups. SCF, LRG1, and platelet-lymphocyte ratio (PLR) were significantly decreased (p < 0.05) in non-treated CRC patients than after treated CRC. The combination between SCF and LRG1 showed highly significant difference in CRC patients compared with benign, healthy subjects, and among CRC groups (treated and non-treated) (p < 0.0001). The highest areas under curve (AUCs) were observed when LRG1 was used as a single predictor for discriminating CRC from healthy (0.87), benign (0.84), and non-treated CRC vs treated CRC (0.82). AUCs were jumped to 0.90, 0.84, and 0.84 when LRG1 and SCF were combined.

CONCLUSION

Our study revealed that LRG1 and SCF were potential diagnostic and follow-up markers for CRC.

The Repertoire of Glycan Alterations and Glycoproteins in Human Cancers

Cancer as the leading cause of death worldwide has many issues that still need to be addressed. Since the alterations on the glycan compositions or/and structures (i.e., glycosylation, sialylation, and fucosylation) are common features of tumorigenesis, glycomics becomes an emerging field examining the structure and function of glycans. In the past, cancer studies heavily relied on genomics and transcriptomics with relatively little exploration of the glycan alterations and glycoprotein biomarkers among individuals and populations. Since glycosylation of proteins increases their structural complexity by several orders of magnitude, glycome studies resulted in highly dynamic biomarkers that can be evaluated for cancer diagnosis, prognosis, and therapy. Glycome not only integrates our genetic background with past and present environmental factors but also offers a promise of more efficient patient stratification compared with genetic variations. Therefore, studying glycans holds great potential for better diagnostic markers as well as developing more efficient treatment strategies in human cancers. While recent developments in glycomics and associated technologies now offer new possibilities to achieve a high-throughput profiling of glycan diversity, we aim to give an overview of the current status of glycan research and the potential applications of the glycans in the scope of the personalized medicine strategies for cancer.

Comprehensive Serum Glycopeptide Spectra Analysis Combined with Artificial Intelligence (CSGSA-AI) to Diagnose Early-Stage Ovarian Cancer

Ovarian cancer is a leading cause of deaths among gynecological cancers, and a method to detect early-stage epithelial ovarian cancer (EOC) is urgently needed. We aimed to develop an artificial intelligence (AI)-based comprehensive serum glycopeptide spectra analysis (CSGSA-AI) method in combination with convolutional neural network (CNN) to detect aberrant glycans in serum samples of patients with EOC. We converted serum glycopeptide expression patterns into two-dimensional (2D) barcodes to let CNN learn and distinguish between EOC and non-EOC. CNN was trained using 60% samples and validated using 40% samples. We observed that principal component analysis-based alignment of glycopeptides to generate 2D barcodes significantly increased the diagnostic accuracy (88%) of the method. When CNN was trained with 2D barcodes colored on the basis of serum levels of CA125 and HE4, a diagnostic accuracy of 95% was achieved. We believe that this simple and low-cost method will increase the detection of EOC.

The Prognostic Impact of Leucine-Rich α-2-Glycoprotein-1 in Cholangiocarcinoma and Its Association With the IL-6/TGF-β1 Axis

BACKGROUND

Leucine-rich α-2-glycoprotein-1 (LRG) has been found to participate in the development of various cancers through its involvement in TGF-β1-induced epithelial-mesenchymal transition (EMT) and/or angiogenesis and can be induced by inflammatory cytokines, such as IL-6. As we previously showed the implication of IL-6/TGF-β axis in EMT of cholangiocarcinoma cells, we herein explored the prognostic impact of LRG in postoperative intrahepatic cholangiocarcinoma (ICC) and assessed the association between tumor LRG and factors such as TGF-β1, IL-6, and the tumor microvessel density.

METHODS

We determined the expression of LRG, IL-6, TGF-β1, and CD31 in cancer tissues from 50 ICC patients by immunohistochemistry and analyzed their association with the prognosis.

RESULTS

The LRG expression was closely associated with recurrence-free survival (RFS) and overall survival (OS) in postoperative ICC. A multivariate Cox regression model indicated that LRG as an independently associated with poor RFS (hazard ratio = 2.4339, P = 0.0354) and OS (hazard ratio = 2.8892, P = 0.0268). The LRG expression was significantly associated with the expression of TGF-β1 (P = 0.0003) and IL-6 (P = 0.0164).

CONCLUSIONS

The upregulation of LRG in tumors was an independent prognostic factor in patients with postoperative ICC. LRG was closely associated with the TGF-β1 expression and seems to be an important member of the IL-6/TGF-β1 axis.

Leucine-rich alpha 2 glycoprotein is a new marker for active disease of tuberculosis

Tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) is a global health problem. At present, prior exposure to Mtb can be determined by blood-based interferon-gamma release assay (IGRA), but active TB is not always detectable by blood tests such as CRP and ESR. This study was undertaken to investigate whether leucine-rich alpha-2 glycoprotein (LRG), a new inflammatory biomarker, could be used to assess active disease of TB. Cynomolgus macaques pretreated with or without Bacille Calmette-Guerin (BCG) vaccination were inoculated with Mtb to induce active TB. Blood was collected over time from these animals and levels of LRG as well as CRP and ESR were quantified. In the macaques without BCG vaccination, Mtb inoculation caused extensive TB and significantly increased plasma CRP and LRG levels, but not ESR. In the macaques with BCG vaccination, whereas Mtb challenge caused pulmonary TB, only LRG levels were significantly elevated. By immunohistochemical analysis of the lung, LRG was visualized in epithelioid cells and giant cells of the granulation tissue. In humans, serum LRG levels in TB patients were significantly higher than those in healthy controls and declined one month after anti-tubercular therapy. These findings suggest that LRG is a promising biomarker when performed following IGRA for the detection of active TB.

LRG1 Suppresses Migration and Invasion of Esophageal Squamous Cell Carcinoma by Modulating Epithelial to Mesenchymal Transition

Background: Esophageal squamous cell carcinoma (ESCC) is a common cancer with poor prognosis. The molecular pathogenesis underlying ESCC remains to be explored. Leucine-rich ɑ-2-glycoprotein 1 (LRG1) has been implicated in the pathogenesis of various cancer types, however its role in ESCC is unknown.

Materials and Methods: Data from the public database was analyzed to address the expression of LRG1 in ESCC. Gain-of-function studies were performed in select ESCC cell lines by over-expression or addition of recombinant LRG1, while loss-of-function studies achieved by small interfering RNA mediated knockdown. Wound healing and transwell assays were conducted to investigate ESCC cell migration and invasion upon manipulating LRG1 levels. Western blot and Immunofluorescence staining were used to examine the changes in epithelial to mesenchymal transition (EMT) and TGFβ signaling pathway.

Results: LRG1 mRNA levels were found to be significantly down-regulated in patients with ESCC as well as in several ESCC cell lines. Silencing of LRG1 promoted, while overexpression of LRG1 inhibited ESCC cell migration and invasion. In line with this, Silencing of LRG1 enhanced, while overexpression of LRG1 reduced TGFβ signaling and EMT of ESCC cells.

Conclusion/Significance: LRG1 suppresses ESCC cell migration and invasion via negative modulation of TGFβ signaling and EMT. Down-regulation of LRG1 in ESCC patients may favor tumor metastasis and disease progression.

Serum extracellular vesicles contain SPARC and LRG1 as biomarkers of colon cancer and differ by tumour primary location

BACKGROUND

Recently, the distinction between left- and right-sided colon cancer (LCC and RCC) has been brought into focus. RCC is associated with an inferior overall survival and progression-free survival. We aimed to perform a detailed analysis of the diversity of extracellular vesicles (EV) between LCC and RCC using quantitative proteomics and to identify for new diagnostic and prognostic biomarkers.

METHODS

We isolated EVs from patients with LCC, RCC and healthy volunteers, and treated colorectal cancer cell line with serum-derived EVs. We then performed a quantitative proteomics analysis of the serum-derived EVs and cell line treated with EVs. Proteomic data are available via ProteomeXchange with the identifiers PXD012283 and PXD012304. In addition, we assessed the performance of EV SPARC and LRG1 as diagnosis and prognosis biomarkers in colon cancer.

FINDINGS

The expression profile of the serum EV proteome in patients with RCC was different from that of patients with LCC. Serum-derived EVs in RCC promoted cellular mobility more significantly than EVs derived from LCC. EV SPARC and LRG1 expression levels demonstrated area under the receiver-operating characteristic curve values of 0.95 and 0.93 for discriminating patients with colon cancer from healthy controls. Moreover, the expression levels of SPARC and LRG1 correlated with tumour sidedness and were predictive of tumour recurrence.

INTERPRETATION

We identified differences in EV protein profiles between LCC and RCC. Serum-derived EVs of RCC may promote metastasis via upregulation of extracellular matrix (ECM)-related proteins, especially SPARC and LRG1, which may serve as diagnosis and prognosis biomarkers in colon cancer.

Fucosylation in cancer biology and its clinical applications

Fucosylation is the process of transferring fucose from GDP-fucose to their substrates, which includes certain proteins, N- and O-linked glycans in glycoprotein or glycolipids, by fucosyltransferases in all mammalian cells. Fucosylated glycans play vital role in selectin-mediated leukocyte extravasation, lymphocyte homing, and pathogen-host interactions, whereas fucosylated proteins are essential for signaling transduction in numerous ontogenic events. Aberrant fucosylation due to the availability of high energy donor GDP-fucose, abnormal expression of FUTs and/or α-fucosidase, and the availability of their substrates leads to different fucosylated glycan or protein structures. Accumulating evidence demonstrates that aberrant fucosylation plays important role in all aspects of cancer biology. In this review, we will summarize the current knowledge about fucosylation in different physiological and pathological processes with a focus on their roles not only in cancer cell proliferation, invasion, and metastasis but also in tumor immune surveillance. Furthermore, the clinical potential and applications of fucosylation in cancer diagnosis and treatment will also be discussed.