Bikunin loss in urine as useful marker for bladder carcinoma

Molecular and pathobiological insights of bikunin/UTI in cancer

Bikunin is a small chondroitin sulfate proteoglycan (PG) with Ser-protease inhibitory activity that plays pleiotropic roles in health and disease. It is involved in several physiological processes including stabilization of the extracellular matrix (ECM) of connective tissues and key reproductive events. Bikunin is also implicated in both acute and chronic inflammatory conditions and represents a non-invasive circulating and/or urinary (as Urinary Trypsin Inhibitor or UTI) biomarker. It exerts inhibitory effects on urokinase-type plasminogen activator (uPA) and its receptor (uPAR) mediating tumor invasiveness by a down-regulation of uPA mRNA expression, thus representing an anti-metastatic agent. However, only limited data on its potential as a diagnostic and/or prognostic marker of cancer have been reported so far. Recent technological advances in mass spectrometry-based proteomics have provided researchers with a huge amount of information allowing for large-scale surveys of the cancer proteome. To address such issues, we analyzed bikunin expression data across several types of tumors, by using UALCAN proteogenomic analysis portal. In this article we critically review the roles of bikunin in human pathobiology, with a special focus on its inhibitory effects and mechanisms in cancer aggressiveness as well as its significance as cancer circulating biomarker.

A Method for Urinary Trypsin Inhibitor (UTI) Purification Combining Anion-Exchange Chromatography Enrichment and Preparative SDS-PAGE

This chapter describes a method for the purification of urinary trypsin inhibitor (UTI), a small chondroitin sulfate proteoglycan with Ser-proteinase inhibitory activity, excreted at high levels into urine following an inflammatory condition. The method consists of two fractionation steps: an anion-exchange chromatography and a sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) followed by Coomassie Brilliant Blue G-250 gel staining. Several UTI bands are excised from gel, minced, destained, and dehydrated for extraction with SDS-containing buffer, at 60 °C for 24 h. This allows for obtaining a highly purified UTI sample useful for both structural and functional studies.

The Inter-α-Trypsin Inhibitor Family: Versatile Molecules in Biology and Pathology

Inter-α-trypsin inhibitor (IαI) family members are ancient and unique molecules that have evolved over several hundred million years of vertebrate evolution. IαI is a complex containing the proteoglycan bikunin to which heavy chain proteins are covalently attached to the chondroitin sulfate chain. Besides its matrix protective activity through protease inhibitory action, IαI family members interact with extracellular matrix molecules and most notably hyaluronan, inhibit complement, and provide cell regulatory functions. Recent evidence for the diverse roles of the IαI family in both biology and pathology is reviewed and gives insight into their pivotal roles in tissue homeostasis. In addition, the clinical uses of these molecules are explored, such as in the treatment of inflammatory conditions including sepsis and Kawasaki disease, which has recently been associated with severe acute respiratory syndrome coronavirus 2 infection in children.

Role of the small proteoglycan bikunin in human reproduction

PURPOSE

Female reproductive events, including ovulation, menstruation, implantation, and delivery, are physiologically characterized by deep tissue remodeling and display hallmark signs of inflammation. This review discusses the pleiotropic roles played by bikunin in human reproduction.

METHODS

A comprehensive literature search of the Medline/PubMed database was performed on the following topics: bikunin structure, roles in pathophysiological conditions and involvement in human reproduction, and usefulness as a marker of gestational complications or as a drug to improve pregnancy outcomes.

RESULTS

Bikunin is a small chondroitin sulfate proteoglycan found in blood, urine, and amniotic and cerebrospinal fluids, known for its anti-inflammatory and anti-proteolytic activities. Its levels are usually low, but they can increase several-fold in both acute and chronic inflammatory diseases. Bikunin plays key roles in reproductive events, such as cumulus-oocyte complex formation, pregnancy, and delivery. Its levels have been associated with the most common pregnancy complications such as preterm delivery, pre-eclampsia, and gestational diabetes mellitus. Finally, its intravaginal administration has been reported to reduce the risk of preterm delivery and to improve neonatal outcomes.

CONCLUSIONS

Because of its pleiotropic roles in several reproductive events and its association with some life-threatening pathological conditions of pregnancy, bikunin may represent a non-invasive marker for improving follow-up and early diagnosis. Studies showing its usefulness as a drug for reducing the risk of preterm delivery and improving neonatal outcomes have yielded interesting results that deserve to be investigated through further research.

Levels of Urinary Trypsin Inhibitor and Structure of Its Chondroitin Sulphate Moiety in Type 1 and Type 2 Diabetes

BACKGROUND

Diabetes mellitus is a global health problem representing the fifth leading cause of mortality and a major risk factor for cardiovascular diseases. In the last years, we reported an association among urinary trypsin inhibitor (UTI), a small proteoglycan that plays pleiotropic roles in many inflammatory processes, and both type 1 and 2 diabetes and developed a method for its direct quantitation and structural characterization.

METHODS

Urine from 39 patients affected by type 1 diabetes, 32 patients with type 2 diabetes, and 52 controls were analysed. UTI was separated from the main glycosaminoglycans physiologically present in urine by anion exchange chromatography, treated for chondroitin sulphate (CS) chain complete depolymerisation, and analysed for both UTI content and CS structure. UTI identification was performed by nano-LC-MS/MS analysis.

RESULTS

We evidenced increased UTI levels, as well as reduced sulphation of its CS moiety in association with diabetes, regardless of both age and medium-term glycaemic control. Furthermore, no association between UTI and albumin excretion rate was found.

CONCLUSIONS

Evidences suggest that UTI levels are not directly correlated with renal function or, otherwise, that they may increase before the onset of renal impairment in diabetes, representing a potential marker for the underlying inflammatory condition.

Ten Years of Proteomics in Bladder Cancer: Progress and Future Directions

Research efforts targeting the identification of bladder cancer biomarkers have been extensive during the past decade. Investigations have been performed at the genome, transcriptome, proteome, and metabolome levels and outputs have started appearing including the sketching of disease molecular subtypes. Proteins are directly linked to cell phenotype hence they accumulate special interest as both biomarkers and therapeutic targets. Multiple technical challenges exist, of the main, being the protein concentration vast dynamic range and presence of proteins in modified forms. The scope of this review is to summarize the contribution of proteomics research in this quest of bladder cancer biomarkers. To obtain an unbiased and comprehensive overview, the scientific literature was searched for manuscripts describing proteomic studies on urothelial cancer from the last ten years and those including independent verification studies in urine, tissue and blood are briefly presented. General observations include: a) in most cases, suboptimal experimental design including healthy controls in biomarker discovery and frequently biomarker verification, is followed; b) variability in protein findings between studies can be observed, to some extent reflecting complexity of experimental approaches and proteome itself; c) consistently reported biomarkers include mainly plasma proteins and d) compilation of protein markers into diagnostic panels appears the most promising way forward. Two main avenues of research can now be foreseen: targeting integration of the existing disparate data with proteomic findings being placed in the context of existing knowledge on bladder cancer subtypes and in parallel, accumulation of clinical samples to support proper validation studies of promising marker combinations.

Significance of urinary glycosaminoglycans/proteoglycans in the evaluation of type 1 and type 2 diabetes complications

Because of the high incidence of kidney disease in diabetic patients, the early diagnosis of renal impairment is a key point for intervention and management. Although urinary albumin excretion currently represents the accepted standard to assess both diabetic nephropathy and cardiovascular risk, it has some limitations as structural changes in the glomerular basement membrane may occur before the onset of microalbuminuria. It is therefore important to identify urinary markers that may provide greater sensitivity, earlier detection, and greater predictive power for diabetes complications. In this respect, urinary glycosaminoglycans/proteoglycans (GAGs/PGs) have been long associated with several kidney diseases as well as diabetic nephropathies as their levels increase more readily than albuminuria. In particular, heparan sulfate, a key component of the glomerular basement membrane responsible for its charge-dependent permeability, is excreted into urine at higher concentrations during the early kidney remodeling events caused by the altered glucose metabolism in diabetes. Over the past few years, also urinary trypsin inhibitor has been linked to a chronic inflammatory condition in both type 1 and 2 diabetes. The underlying mechanisms of such increase are not completely known since either a systemic inflammatory condition or a more localized early renal impairment could play a role. Nevertheless, the association with other inflammatory markers and a detailed urinary trypsin inhibitor structural characterization in diabetes remain to be elucidated. This review will discuss a great deal of information on the association between urinary GAGs/PGs and type 1 and 2 diabetes, with particular emphasis on renal involvement, and their potential as markers useful in screening, diagnosis and follow up to be associated with the current standard tests.

Proteomic identification of potential cancer markers in human urine using subtractive analysis

Urine is an ideal medium in which to focus diagnostic cancer research due to the non-invasive nature and ease of sampling. Many large-scale proteomic studies have shown that urine is unexpectedly complex. We hypothesised that novel diagnostic cancer biomarkers could be discovered using a comparative proteomic analysis of pre-existing data. We assembled a database of 100 published datasets of 5,620 urinary proteins, as well as 46 datasets of 8,620 non-redundant proteins derived from kidney and blood proteome analyses. The data were then used to either subtract or compare molecules from a novel urinary proteome profiling dataset that we generated. We identified 1,161 unique proteins in samples from either cancer-bearing or healthy subjects. Subtractive analysis yielded a subset of 44 proteins that were found uniquely in urine from cancer patients, 30 of which were linked previously to cancer. In conclusion, this approach is useful in discovering novel biomarkers in tissues where unrelated profiling data is available. Only a limited disease-specific novel dataset is required to define new targets or substantiate previous findings. We have shared this discovery platform in the form of our Large Scale Screening Resource database, accessible through the Proteomic Analysis DataBase portal (www.PADB.org).

Low Mass Blood Peptides Discriminative of Inflammatory Bowel Disease (IBD) Severity: A Quantitative Proteomic Perspective

Breakdown of the protective gut barrier releases effector molecules and degradation products into the blood stream making serum and plasma ideal as a diagnostic medium. The enriched low mass proteome is unexplored as a source of differentiators for diagnosing and monitoring inflammatory bowel disease (IBD) activity, that is less invasive than colonoscopy. Differences in the enriched low mass plasma proteome (<25 kDa) were assessed by label-free quantitative mass-spectrometry. A panel of marker candidates were progressed to validation phase and "Tier-2" FDA-level validated quantitative assay. Proteins important in maintaining gut barrier function and homeostasis at the epithelial interface have been quantitated by multiple reaction monitoring in plasma and serum including both inflammatory; rheumatoid arthritis controls, and non-inflammatory healthy controls; ulcerative colitis (UC), and Crohn's disease (CD) patients. Detection by immunoblot confirmed presence at the protein level in plasma. Correlation analysis and receiver operator characteristics were used to report the sensitivity and specificity. Peptides differentiating controls from IBD originate from secreted phosphoprotein 24 (SPP24, p = 0.000086, 0.009); whereas those in remission and healthy can be differentiated in UC by SPP24 (p = 0.00023, 0.001), α-1-microglobulin (AMBP, p = 0.006) and CD by SPP24 (p = 0.019, 0.05). UC and CD can be differentiated by Guanylin (GUC2A, p = 0.001), and Secretogranin-1 (CHGB p = 0.035). Active and quiescent disease can also be differentiated in UC and CD by CHGB (p ≤ 0.023) SPP24 (p ≤ 0.023) and AMBP (UC p = 0.046). Five peptides discriminating IBD activity and severity had very little-to-no correlation to erythrocyte sedimentation rate, C-reactive protein, white cell or platelet counts. Three of these peptides were found to be binding partners to SPP24 protein alongside other known matrix proteins. These proteins have the potential to improve diagnosis and evaluate IBD activity, reducing the need for more invasive techniques. Data are available via ProteomeXchange with identifier PXD002821.

Positive Mode LC-MS/MS Analysis of Chondroitin Sulfate Modified Glycopeptides Derived from Light and Heavy Chains of The Human Inter-α-Trypsin Inhibitor Complex

The inter-α-trypsin inhibitor complex is a macromolecular arrangement of structurally related heavy chain proteins covalently cross-linked to the chondroitin sulfate (CS) chain of the proteoglycan bikunin. The inter-α-trypsin inhibitor complex is abundant in plasma and associated with inflammation, kidney diseases, cancer and diabetes. Bikunin is modified at Ser-10 by a single low-sulfated CS chain of 23-55 monosaccharides with 4-9 sulfate groups. The innermost four monosaccharides (GlcAβ3Galβ3Galβ4Xylβ-O-) compose the linkage region, believed to be uniform with a 4-O-sulfation to the outer Gal. The cross-linkage region of the bikunin CS chain is located in the nonsulfated nonreducing end, (GalNAcβ4GlcAβ3)(n), to which heavy chains (H1-H3) may be bound in GalNAc to Asp ester linkages. In this study we employed a glycoproteomics protocol to enrich and analyze light and heavy chain linkage and cross-linkage region CS glycopeptides derived from the IαI complex of human plasma, urine and cerebrospinal fluid samples. The samples were trypsinized, enriched by strong anion exchange chromatography, partially depolymerized with chondroitinase ABC and analyzed by LC-MS/MS using higher-energy collisional dissociation. The analyses demonstrated that the CS linkage region of bikunin is highly heterogeneous. In addition to sulfation of the Gal residue, Xyl phosphorylation was observed although exclusively in urinary samples. We also identified novel Neu5Ac and Fuc modifications of the linkage region as well as the presence of mono- and disialylated core 1 O-linked glycans on Thr-17. Heavy chains H1 and H2 were identified cross-linked to GalNAc residues one or two GlcA residues apart and H1 was found linked to either the terminal or subterminal GalNAc residues. The fragmentation behavior of CS glycopeptides under variable higher-energy collisional dissociation conditions displays an energy dependence that may be used to obtain complementary structural details. Finally, we show that the analysis of sodium adducts provides confirmatory information about the positions of glycan substituents.

Developing proteomic biomarkers for bladder cancer: towards clinical application

Clinical use of proteomic biomarkers has the potential to substantially improve the outcomes of patients with bladder cancer. An unmet clinical need evidently exists for noninvasive biomarkers, which might enable improvements in both the diagnosis and prognosis of patients with bladder cancer, as well as improved monitoring of patients for the presence of recurrence. Urine is considered the optimal noninvasive source of proteomic biomarkers in patients with bladder cancer. Currently, a number of single-protein biomarkers have been detected in urine and tissue using a variety of proteomic techniques, each having specific conceptual considerations and technical implications. Promising preclinical data are available for several of these proteins; however, the combination of single urinary proteins into multimarker panels might better encompass the molecular heterogeneity of bladder cancer within this patient population, and prove more effective in clinical use.

The expression sequence tag is an effective method for screening DNA segments that predict urinary bladder transitional cell carcinoma prognosis

Purpose

We validated the use of expression sequence tags (ESTs) as an effective method of screening for DNA segments that could predict urothelial cell carcinoma and for identifying ESTs with such predictive value.

Patients and methods

From 2004 to 2009, eleven patients were enrolled in this study: six with high-grade bladder carcinoma and five with low-grade bladder carcinoma. ESTs were used to screen for differential gene expression in a high-grade cell line (MGH-U1) and in a premalignant cell line (MGH-U4). Immunohistochemistry and real-time reverse transcription-polymerase chain reaction were used to validate the degree of EST expression and the prognostic value of ESTs.

Results

Apoferritin H subunit (FTH1 protein) exhibited increased expression in high-grade bladder carcinoma compared with that seen in low-grade carcinoma. Immunohistochemistry and real-time reverse transcription-polymerase chain reaction both supported the higher expression of FTH1 in high-grade urothelial carcinoma.

Conclusion

ESTs are useful for detecting the FTH1 protein, which predicts the prognosis of patients with bladder carcinoma.

Urine of patients with early prostate cancer contains lower levels of light chain fragments of inter-alpha-trypsin inhibitor and saposin B but increased expression of an inter-alpha-trypsin inhibitor heavy chain 4 fragment

The present study was aimed at the identification of proteins that are differentially expressed in the urine of patients with prostate cancer (PCa), those with benign prostatic hyperplasia (BPH) and age-matched healthy male control subjects. Using a combination of 2DE and MS/MS, significantly lower expression of urinary saposin B and two different fragments of inter-alpha-trypsin inhibitor light chain (ITIL) was demonstrated in the PCa patients compared to the controls. However, only one of the ITIL fragments was significantly different between the PCa and BPH patients. When image analysis was performed on urinary proteins that were transferred onto NC membranes and detected using a lectin that binds to O-glycans, a truncated fragment of inter-alpha-trypsin inhibitor heavy chain 4 was the sole protein found to be significantly enhanced in the PCa patients compared to the controls. Together, these urinary peptide fragments might be useful complementary biomarkers to indicate PCa as well as to distinguish it from BPH, although further epidemiological evidence on the specificity and sensitivity of the protein candidates is required.

Proteomic studies of urinary biomarkers for prostate, bladder and kidney cancers

Urine is an ideal body fluid for the detection of protein markers produced by urological cancers as it can be sampled noninvasively and contains secreted and directly shed proteins from the prostate, bladder and kidney. Major challenges of working with urine include high inter-individual and intra-individual variability, low protein concentration, the presence of salts and the dynamic range of protein expression. Despite these challenges, significant progress is being made using modern proteomic methods to identify and characterize protein-based markers for urological cancers. The development of robust, easy-to-use clinical tests based on novel biomarkers has the potential to impact upon diagnosis, prognosis and monitoring and could revolutionize the treatment and management of these cancers.

Does phosphorylation of cofilin affect the progression of human bladder cancer?

Background

We determined the differently expressed protein profiles and their functions in bladder cancer tissues with the aim of identifying possible target proteins and underlying molecular mechanisms for taking part in their progression.

Methods

We examined the expression of proteins by proteomic analysis and western blot in normal urothelium, non-muscle-invasive bladder cancers (NMIBCs), and muscle-invasive bladder cancers (MIBCs). The function of cofilin was analyzed using T24 human bladder cancer cells.

Results

The expression levels of 12 proteins were altered between bladder cancers and normal bladder tissues. Of these proteins, 14-3-3σ was upregulated in both NMIBCs and MIBCs compared with controls. On the other hand, myosin regulatory light chain 2, galectin-1, lipid-binding AI, annexin V, transthyretin, CARD-inhibitor of NF-κB-activating ligand, and actin prepeptide were downregulated in cancer samples. Cofilin, an actin-depolymerizing factor, was prominent in both NMIBCs and MIBCs compared with normal bladder tissues. Furthermore, we confirmed that cofilin phosphorylation was more prominent in MIBCs than in NMIBCs using immunoblotting and immunohistochemcal analyses. Epidermal growth factor (EGF) increased the phosphorylation of cofilin and elevated the migration in T24 cells. Knockdown of cofilin expression with small interfering RNA attenuated the T24 cell migration in response to EGF.

Conclusions

These results demonstrate that the increased expression and phosphorylation of cofilin might play a role in the occurrence and invasiveness of bladder cancer. We suspected that changes in cofilin expression may participate in the progression of the bladder cancer.

Discovery of potential bladder cancer biomarkers by comparative urine proteomics and analysis

OBJECTIVE

We searched for bladder tumor markers by analyzing urine samples from patients with bladder cancer and from normal controls.

METHODS

Proteins in urine samples of patients with bladder cancer and with normal controls were systematically examined by 2-dimensional electrophoresis combined with matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The expression of the protein apolipoprotein A-I (apoA-I) was confirmed by Western blot analysis and further evaluated.

RESULTS

We successfully obtained the 2-dimensional electrophoresis gel maps of urinary proteins in patients with bladder cancer and in normal controls. Thirty differentially expressed protein spots were successfully matched by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Combined with the SWISS-PROT database, only 14 proteins (beta-2-microglobulin, fatty acid-binding protein adipocyte, gelsolin, isoform 1 of gelsolin, myoglobin, isoform 2 of fibrinogen alpha chain, apoA-I, prostaglandin D(2) synthase 21 kDa [brain], protein AMBP, transthyretin, keratin type II cytoskeletal 1, type II cytoskeletal 8, putative uncharacterized protein ALB, putative uncharacterized protein MASP2 [fragment]) were identified, including 2 putative proteins. Furthermore, apoA-I was confirmed by Western blot analysis, and the high level of apoA-I was found in urine samples from patients with bladder tumors compared with normal controls.

CONCLUSIONS

Analysis of urinary proteome may be a feasible, noninvasive, and efficient strategy for searching for potential bladder tumor biomarkers. A significant relationship of expressed apoA-I was established between bladder cancer and normal controls. We concluded that 14 differential spots included the apoA-I and would be potential urinary biomarkers for the diagnosis and surveillance of bladder cancer.

Identification of urinary Gc-globulin as a novel biomarker for bladder cancer by two-dimensional fluorescent differential gel electrophoresis (2D-DIGE)

Improving the early detection rate and surveillance of bladder cancer remains a great challenge in medicine. Here, we identified sixteen proteins including Gc-globulin (GC) in urine from bladder cancer patients and normal controls by two-dimensional fluorescent differential gel electrophoresis (2D-DIGE) and matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF/TOF MS). Bioinformatics analyses indicated GC played important roles in the regulation of growth, apoptosis, death and epidermal growth factor receptor activity. The GC expression patterns in urine or tissue from cases and controls were further quantified by western blotting, immunohistochemical staining and enzyme-linked immunosorbent assay (ELISA). ELISA quantification by correcting for creatinine expression showed GC-Cr was significantly increased in bladder cancer patients than in benign bladder damages cases and normal controls (1013.70±851.25 versus 99.34±55.87, 105.32±47.81 ng/mg, respectively). Receiver operating characteristic (ROC) analysis suggested that at 161.086 ng/mg urinary GC, bladder cancer could be detected with 92.31% sensitivity and 83.02% specificity, and 1407.481 ng/mg with 82.61% sensitivity and 88.24% specificity could be used for the detection of infiltrating urothelial carcinoma of bladder cancer. Taken together, we identified GC as a potential novel urinary biomarker for the early detection and surveillance of bladder cancer.

DDX39 acts as a suppressor of invasion for bladder cancer

The object of the present study was to identify markers for predicting urinary bladder cancer progression by comparative proteome analysis of bladder cancers and paired normal mucosas. We found that DDX39 was overexpressed in four of six bladder cancers examined compared with respective control tissues. Immunohistochemical analysis using 303 bladder cancer specimens revealed that DDX39 was inversely correlated to pT stage and histological grade progression. The incidence of DDX39(high) tumors (positive cells ≥50%) was 68.6%, 43.5%, 20.0%, and 5.3% in pTa, pT1, pTis, and ≥pT2 tumors, respectively, and 65.2%, 60.7%, and 19.6% in G1, G2, and G3 tumors, respectively. The incidence of DDX39(high) tumors was significantly lower in pT1 and ≥pT2 compared to pTa tumors, and also significantly lower in G3 compared to G1 and G2 tumors. Follow-up analysis (n = 105) revealed that DDX39(low) tumors (positive cells <50%) were associated with disease progression (hazard ratio 7.485; P = 0.0083). Furthermore, DDX39-knockdown bladder cancer cells increased their invasion ability compared to negative control cells. These results suggest that DDX39 is a suppressor of invasion and loss of its function predicts disease progression in bladder cancers.