Serum level of galectin-3 in human bladder cancer

Biomarkers in Cancer Detection, Diagnosis, and Prognosis

Biomarkers are vital in healthcare as they provide valuable insights into disease diagnosis, prognosis, treatment response, and personalized medicine. They serve as objective indicators, enabling early detection and intervention, leading to improved patient outcomes and reduced costs. Biomarkers also guide treatment decisions by predicting disease outcomes and facilitating individualized treatment plans. They play a role in monitoring disease progression, adjusting treatments, and detecting early signs of recurrence. Furthermore, biomarkers enhance drug development and clinical trials by identifying suitable patients and accelerating the approval process. In this review paper, we described a variety of biomarkers applicable for cancer detection and diagnosis, such as imaging-based diagnosis (CT, SPECT, MRI, and PET), blood-based biomarkers (proteins, genes, mRNA, and peptides), cell imaging-based diagnosis (needle biopsy and CTC), tissue imaging-based diagnosis (IHC), and genetic-based biomarkers (RNAseq, scRNAseq, and spatial transcriptomics).

Soluble IgE-binding factors in the serum of food-allergic patients: Possible pathophysiological role of soluble FcεRI as protective factor

BACKGROUND

IgE-mediated food allergy is the result of an aberrant immune response involving the interaction of a food allergen with its specific IgE bound to FcɛRI, the high affinity IgE receptor, on mast cells. Allergen-specific IgE also binds to soluble binding factors, but, their expression and role in food allergy is not well characterized. Here, we assess the prevalence and relevance of soluble IgE binding factors in food allergy and tolerance.

METHODS

We measured serum levels of four IgE binding factors, that is, galectin-3, galectin-9, soluble FcɛRI (sFcεRI) and soluble CD23 (sCD23) in 67 adults sensitized to peanut or hazelnut and sFcɛRI in 29 children sensitized to hen's egg. Adults without food allergen sensitization (n = 17) served as healthy controls. We compared serum levels of patients and controls and assessed them, in the former, for links to clinical features including allergy and tolerance.

RESULTS

Serum levels of sFcɛRI and sCD23, but not galectin-3 and galectin-9, significantly differ in food-sensitized patients as compared to healthy controls. A subgroup (28%) of peanut and hazelnut allergic patients had elevated sFcεRI levels, that were associated with higher total and specific IgE levels. Furthermore, sFcεRI levels were significantly higher in tolerant subjects compared to allergics. Among hazelnut allergic patients, those with high sFcεRI levels tolerated the highest protein amounts in the oral food challenge.

CONCLUSION

sFcɛRI but not sCD23, galectin-3 and galectin-9 might play a role in the pathophysiology of food allergy. Its functional role or use as biomarker should be assessed in further studies.

Galectin-3 as a biomarker in breast neoplasms: Mechanisms and applications in patient care

Galectin-3 is a member of the lectin family encoded by the LGALS3 gene on chromosome 14. It is secreted by a wide range of immune cells and mammary tumor cells. Through its activity on the tumor microenvironment, in particular on tumor-infiltrating leukocytes, galectin-3 improves the proliferation, survival, and colonizing ability of mammary neoplastic cells. Consequently, galectin-3 expression in the tumor microenvironment could worsen therapeutic outcomes of breast neoplasms and become a biomarker and a therapeutic target in combined immunotherapy in breast neoplasms. There is a limited amount of information that is available on galectin-3 in breast cancer in Africa. In this review, we analyze how galectin-3 influences the tumor microenvironment and its potential as a biomarker and therapeutic target in breast neoplasms. We aim to emphasize the significance of investigating galectin-3 in breast neoplasms in Africa based on the results of studies conducted elsewhere.

Assessment of galectins -1, -3, -4, -8, and -9 expression in ovarian carcinoma patients with clinical implications

Background and aim

Galectins have been recently tackled by many researchers in the field of cancer due to their role in tumorigenesis, disease progression, and metastasis. Thus, they are currently involved in biomarkers research on several types of cancer. In ovarian cancers, few studies were carried out to evaluate galectins expression profiling. Hence, our present study was executed to evaluate the mRNA expression of galectins -1, -3, -4, -8, and -9 in epithelial ovarian cancers.

Methods

Fifty-six tumor samples of ovarian carcinomas were analyzed for mRNA expression using qRT-PCR, and fold-changes were calculated in comparison to tissue samples of 26 women with normal ovaries.

Results

The results of the present paper emphasize the importance of galectins as predictors for targeted therapy. LGALS1, LGALS3, LGALS4, LGALS8, and LGALS9 were found to be mostly overexpressed in ovarian carcinoma patients with the following percentage: 78.6%, 92.9%, 66.1%, 87.5%, and 85.7% respectively. Moreover, galectins -3 and -9 were found to be significantly elevated with lymph node metastasis (p = 0.044 and p = 0.011). Also, upregulation of galectin-1 and -9 were statistically significant in stages IIB, IIC, and IIIB (p = 0.002) in FIGO staging. CA19.9 is positively correlated to galectin-4 expression (p = 0.039).

Conclusion

Our findings strengthen the role of galectins in carcinogenesis, disease progression, and lymphnode metastasis in ovarian carcinomas. And since these galectins are mostly overexpressed, they could be promising markers for targeted therapy to reduce disease progression and metastasis process.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-022-02738-4.

KIT Mutations Correlate with Higher Galectin Levels and Brain Metastasis in Breast and Non-Small Cell Lung Cancer

To investigate a potential role for galectins as biomarkers that enable diagnosis or prognostication of breast or non-small cell lung cancer, the serum levels of galectins -1, -3, -7, -8, and -9 of cancer patients determined by ELISA assays were compared to the mutation status of 50 known cancer-critical genes, which were determined using multiplex PCR in tumors of the same patients. Mutations in the KIT proto-oncogene, which codes for the c-Kit protein, a receptor tyrosine kinase, correlated with higher levels of galectins -1, -3, -8, and -9 in breast cancer patients and galectin-1 in non-small cell lung cancer patients. Mutations in the KIT gene were more likely found in brain metastases from both of these primary cancers. The most common KIT mutation in our panel was p.M541L, a missense mutation in the transmembrane domain of the c-Kit protein. These results demonstrate an association between KIT oncogenic signaling and elevated serum galectins in patients with metastatic disease. Changes in protein trafficking and the glycocalyx composition of cancer cells may explain the observed alterations in galectin expression. This study can be useful for the targeted selection of receptor tyrosine kinase and galectin inhibitor anti-cancer treatments.

Nutrient-responsive O-GlcNAcylation dynamically modulates the secretion of glycan-binding protein galectin 3

Endomembrane glycosylation and cytoplasmic O-GlcNAcylation each play essential roles in nutrient sensing, and characteristic changes in glycan patterns have been described in disease states such as diabetes and cancer. These changes in glycosylation have important functional roles and can drive disease progression. However, little is known about the molecular mechanisms underlying how these signals are integrated and transduced into biological effects. Galectins are proteins that bind glycans and that are secreted by a poorly characterized nonclassical secretory mechanism. Once outside the cell, galectins bind to the terminal galactose residues of cell surface glycans and modulate numerous extracellular functions, such as clathrin-independent endocytosis (CIE). Originating in the cytoplasm, galectins are predicted substrates for O-GlcNAc addition and removal; and as we have shown, galectin 3 is a substrate for O-GlcNAc transferase. In this study, we also show that galectin 3 secretion is sensitive to changes in O-GlcNAc levels. We determined using immunoprecipitation and Western blotting that there is a significant difference in O-GlcNAcylation status between cytoplasmic and secreted galectin 3. We observed dramatic alterations in galectin 3 secretion in response to nutrient conditions, which were dependent on dynamic O-GlcNAcylation. Importantly, we showed that these O-GlcNAc-driven alterations in galectin 3 secretion also facilitated changes in CIE. These results indicate that dynamic O-GlcNAcylation of galectin 3 plays a role in modulating its secretion and can tune its function in transducing nutrient-sensing information coded in cell surface glycosylation into biological effects.

Galectin-3: A factotum in carcinogenesis bestowing an archery for prevention

Cancer metastasis and therapy resistance are the foremost hurdles in oncology at the moment. This review aims to pinpoint the functional aspects of a unique multifaceted glycosylated molecule in both intracellular and extracellular compartments of a cell namely galectin-3 along with its metastatic potential in different types of cancer. All materials reviewed here were collected through the search engines PubMed, Scopus, and Google scholar. Among the 15 galectins identified, the chimeric gal-3 plays an indispensable role in the differentiation, transformation, and multi-step process of tumor metastasis. It has been implicated in the molecular mechanisms that allow the cancer cells to survive in the intravascular milieu and promote tumor cell extravasation, ultimately leading to metastasis. Gal-3 has also been found to have a pivotal role in immune surveillance and pro-angiogenesis and several studies have pointed out the importance of gal-3 in establishing a resistant phenotype, particularly through the epithelial-mesenchymal transition process. Additionally, some recent findings suggest the use of gal-3 inhibitors in overcoming therapeutic resistance. All these reports suggest that the deregulation of these specific lectins at the cellular level could inhibit cancer progression and metastasis. A more systematic study of glycosylation in clinical samples along with the development of selective gal-3 antagonists inhibiting the activity of these molecules at the cellular level offers an innovative strategy for primary cancer prevention.

Galectin-9 as a biomarker of disease severity

Galectin-9 (Gal-9) is a β-galactoside binding lectin known for its immunomodulatory role in various microbial infections. Gal-9 is expressed in all organ systems and localized in the nucleus, cell surface, cytoplasm and the extracellular matrix. It mediates host-pathogen interactions and regulates cell signalling via binding to its receptors. Gal-9 is involved in many physiological functions such as cell growth, differentiation, adhesion, communication and death. However, recent studies have emphasized on the elevated levels of Gal-9 in autoimmune disorders, viral infections, parasitic invasion, cancer, acute liver failure, atopic dermatitis, chronic kidney disease, type-2 diabetes, coronary artery disease, atherosclerosis and benign infertility-related gynecological disorders. In this paper we have reviewed the potential of Gal-9 as a reliable, sensitive and non-invasive biomarker of disease severity. Tracking changes in Gal-9 levels and its implementation as a biomarker in clinical practice will be an important tool to monitor disease activity and facilitate personalized treatment decisions.

Evaluation of Serum Levels and Expression of Galectin-4 in Cervical Cancer

Galectin-4 has been reported to be altered in different cancer types. Its expression changes have been associated with early recurrence and metastasis. In cervical cancer (CC), galectin-4 has not been studied. The aim of the study was to determine the expression level and subcellular localization of galectin-4 in CC tissue and the concentration in the serum of patients with CC. For the analysis of serum levels of galectin-4, an ELISA assay was performed. To assess the expression in cervical tissue, immunohistochemical staining was performed. The results showed that the concentration of galectin-4 in the serum of patients with CC was higher (647.9 pg/ml) than that in the serum of women with normal cytology (382.1 pg/ml). The immunohistochemical analysis of CC samples showed a higher expression in keratinizing tumor than nonkeratinizing tumors and a trend of increased expression in tumors from patients with advanced clinical stage. In normal cervical tissue, galectin-4 was detected in the cytoplasm, and in tumor cells, the presence of galectin-4 was also detected in the nucleus, in both adenocarcinoma and squamous cervical cancer. The increase in serum concentration and different localization in the tumor cells suggest a possible role of galectin-4 in CC development.

Galectins and Ovarian Cancer

Ovarian cancer is known for its aggressive pathological features, including the capacity to undergo epithelial to mesenchymal transition, promoting angiogenesis, metastatic potential, chemoresistance, inhibiting apoptosis, immunosuppression and promoting stem-like features. Galectins, a family of glycan-binding proteins defined by a conserved carbohydrate recognition domain, can modulate many of these processes, enabling them to contribute to the pathology of ovarian cancer. Our goal herein was to review specific galectin members identified in the context of ovarian cancer, with emphasis on their association with clinical and pathological features, implied functions, diagnostic or prognostic potential and strategies being developed to disrupt their negative actions.

Elevated Soluble Galectin-3 as a Marker of Chemotherapy Efficacy in Breast Cancer Patients: A Prospective Study

Purpose

Galectin-3 (Gal-3) is a glycan-binding lectin with a debated role in cancer progression due to its various functions and patterns of expression. The current study investigates the relationship between breast cancer prognosis and secreted Gal-3.

Methods

Breast cancer patients with first time cancer diagnosis and no prior treatment (n = 88) were placed in either adjuvant or neoadjuvant setting based on their treatment modality. Stromal and plasma Gal-3 levels were measured in each patient at the time of diagnosis and then throughout treatment using immunohistochemistry (IHC) and ELISA, respectively. Healthy women (>18 years of age, n = 63) were used to establish baseline levels of plasma Gal-3. Patients were followed for 84 months for disease-free survival analysis.

Results

Enhanced levels of plasma (adjuvant) and stromal (neoadjuvant) Gal-3 were found to be markers of chemotherapy efficacy. The patients with chemotherapy-induced increase in extracellular Gal-3 had longer disease-free interval and significantly lower rate of recurrence during 84-month follow-up compared to patients with unchanged or decreased secretion.

Conclusion

The findings support the use of plasma Gal-3 as a marker for chemotherapy efficacy when no residual tumor is visible through imaging. Furthermore, stromal levels in any remaining tumors postchemotherapy can also be used to predict long-term prognosis in patients.

Galectins in prostate and bladder cancer: tumorigenic roles and clinical opportunities

Advanced prostate and bladder cancer are two outstanding unmet medical needs for urological oncologists. The high prevalence of these tumours, lack of effective biomarkers and limited effective treatment options highlight the importance of basic research in these diseases. Galectins are a family of β-galactoside-binding proteins that are frequently altered (upregulated or downregulated) in a wide range of tumours and have roles in different stages of tumour development and progression, including immune evasion. In particular, altered expression levels of different members of the galectin family have been reported in prostate and bladder cancers, which, together with the aberrant glycosylation patterns found in tumour cells and the constituent cell types of the tumour microenvironment, can result in malignant transformation and tumour progression. Understanding the roles of galectin family proteins in the development and progression of prostate and bladder cancer could yield key insights to inform the clinical management of these diseases.

PET/CT Imaging with an 18F-Labeled Galactodendritic Unit in a Galectin-1-Overexpressing Orthotopic Bladder Cancer Model

Galectins are carbohydrate-binding proteins overexpressed in bladder cancer (BCa) cells. Dendritic galactose moieties have a high affinity for galectin-expressing tumor cells. We radiolabeled a dendritic galactose carbohydrate with ¹⁸F (¹⁸F-labeled galactodendritic unit 4) and examined its potential in imaging urothelial malignancies. Methods: The ¹⁸F-labeled first-generation galactodendritic unit 4 was obtained from its tosylate precursor. We conducted in vivo studies in a galectin-expressing UMUC3 orthotopic BCa model to determine the ability of ¹⁸F-labeled galactodendritic unit 4 to image BCa. Results: Intravesical administration of ¹⁸F-labeled galactodendritic unit 4 allowed specific accumulation of the carbohydrate radiotracer in galectin-1–overexpressing UMUC3 orthotopic tumors when imaged with PET. The ¹⁸F-labeled galactodendritic unit 4 was not found to accumulate in nontumor murine bladders. Conclusion: The ¹⁸F-labeled galactodendritic unit 4 and similar analogs may be clinically relevant and exploitable for PET imaging of galectin-1–overexpressing bladder tumors.

Glycosylation and glycan interactions can serve as extracellular machinery facilitating clathrin-independent endocytosis

In contrast to clathrin-mediated endocytosis (CME) which is well characterized and understood, little is known about the regulation and machinery underlying clathrin-independent endocytosis (CIE). There is also a wide variation in the requirements each individual CIE cargo has for its internalization. Recent studies have shown that CIE is affected by glycosylation and glycan interactions. We briefly review these studies and explore how these studies mesh with one another. We then discuss what this sensitivity to glycan interactions could indicate for the regulation of CIE. We address the spectrum of responses CIE has been shown to have with respect to changes in glycan interactions and attempt to reconcile disparate observations onto a shared conceptual landscape. We focus on the mechanisms by which cells can alter the glycan interactions at the plasma membrane and propose that glycosylation and glycan interactions could provide cells with a tool box with which cells can manipulate CIE. Altered glycosylation is often associated with a number of diseases and we discuss how under different disease settings, glycosylation-based modulation of CIE could play a role in disease progression.

The Role of Galectins in Tumor Progression, Treatment and Prognosis of Gynecological Cancers

Galectins are the member of soluble proteins that bind with β-galactoside containing glycans. These proteins have been considered to be associated in various important events such as different types of cancers. It has been found that galectins could contribute to neoplastic transformation or regulate cell growth, cell apoptosis, and immune cells, causing tumor invasion, progression, metastasis and angiogenesis. Somehow, galectins are also found to exert a protective effect on cancer in a tissue-dependent way. These glycans binding proteins have been shown to be involved in the regulation of different tumor suppressor genes and oncogenes with their possible roles in human cancers. Objective of the current review is to summarize the role of galectin-1, -3 -7, and -9 in tumorigenesis of gynecological cancers. Galectin protein may be a potential therapeutic target in gynecological malignancies due to reported radio- and chemo- sensitivities, immunotherapeutic, anti-angiogenic and anti-proliferative activities. This review considers the evidence for the future research that how galectins may be important in the progression and treatment of gynecological cancers along with its potent use as a novel prognostic marker.

Galectin-3 Serum Levels Could Help Clinicians Screen for Salivary Gland Tumor Patients

Objective:

To identify serum levels of galectin-3 in salivary gland cancer and healthy populations; a prospective analysis was performed on serum specimens from 105 patients with salivary gland cancer and 56 healthy persons.

Methods:

Enzyme-linked immunosorbent assay (ELISA) was used to measure levels of galectin-3 (GAL-3). Serum levels were compared between patients with salivary gland tumors and healthy control. A total of 105 patients were enrolled in the study (55 men, 50 women).

Result:

Mean age was 45.5 years. Thirty-nine patients with malignant and 66 cases with benign tumors were compared with 56 healthy participants with a mean age of 51.7. No statistically significant differences were observed when comparing GAL-3 serum levels between malignant and benign salivary gland tumor patients, but a statistically significant difference was found between case and control patients with p-values of 0.02. Serum levels of galectin-3 protein were elevated in patients with salivary gland cancer compared with the healthy population.

Conclusion:

The difference between benign and malignant tumor patients was significant, but revealed no clinic pathological characteristics in malignant tumors. To the best of the authors’ knowledge, this is the first time a study suggests that GAL-3 serum levels could help clinicians screen for salivary gland cancer.

Over forty years of bladder cancer glycobiology: Where do glycans stand facing precision oncology?

The high molecular heterogeneity of bladder tumours is responsible for significant variations in disease course, as well as elevated recurrence and progression rates, thereby hampering the introduction of more effective targeted therapeutics. The implementation of precision oncology settings supported by robust molecular models for individualization of patient management is warranted. This effort requires a comprehensive integration of large sets of panomics data that is yet to be fully achieved. Contributing to this goal, over 40 years of bladder cancer glycobiology have disclosed a plethora of cancer-specific glycans and glycoconjugates (glycoproteins, glycolipids, proteoglycans) accompanying disease progressions and dissemination. This review comprehensively addresses the main structural findings in the field and consequent biological and clinical implications. Given the cell surface and secreted nature of these molecules, we further discuss their potential for non-invasive detection and therapeutic development. Moreover, we highlight novel mass-spectrometry-based high-throughput analytical and bioinformatics tools to interrogate the glycome in the postgenomic era. Ultimately, we outline a roadmap to guide future developments in glycomics envisaging clinical implementation.

Galectin-3 interacts with the cell-surface glycoprotein CD146 (MCAM, MUC18) and induces secretion of metastasis-promoting cytokines from vascular endothelial cells

The galactoside-binding protein galectin-3 is increasingly recognized as an important player in cancer development, progression, and metastasis via its interactions with various galactoside-terminated glycans. We have shown previously that circulating galectin-3, which is increased up to 30-fold in cancer patients, promotes blood-borne metastasis in an animal cancer model. This effect is partly attributable to the interaction of galectin-3 with unknown receptor(s) on vascular endothelial cells and causes endothelial secretion of several metastasis-promoting cytokines. Here we sought to identify the galectin-3-binding molecule(s) on the endothelial cell surface responsible for the galectin-3-mediated cytokine secretion. Using two different galectin-3 affinity purification processes, we extracted four cell membrane glycoproteins, CD146/melanoma cell adhesion molecule (MCAM)/MUC18, CD31/platelet endothelial cell adhesion molecule-1 (PECAM-1), CD144/VE-cadherin, and CD106/Endoglin, from vascular endothelial cells. CD146 was the major galectin-3-binding ligand and strongly co-localized with galectin-3 on endothelial cell surfaces treated with exogenous galectin-3. Moreover, galectin-3 bound to N-linked glycans on CD146 and induced CD146 dimerization and subsequent activation of AKT signaling. siRNA-mediated suppression of CD146 expression completely abolished the galectin-3-induced secretion of IL-6 and G-CSF cytokines from the endothelial cells. Thus, CD146/MCAM is the functional galectin-3-binding ligand on endothelial cell surfaces responsible for galectin-3-induced secretion of metastasis-promoting cytokines. We conclude that CD146/MCAM interactions with circulating galectin-3 may have an important influence on cancer progression and metastasis.

Vesicular Galectin-3 levels decrease with donor age and contribute to the reduced osteo-inductive potential of human plasma derived extracellular vesicles

Aging results in a decline of physiological functions and in reduced repair capacities, in part due to impaired regenerative power of stem cells, influenced by the systemic environment. In particular osteogenic differentiation capacity (ODC) of mesenchymal stem cells (MSCs) has been shown to decrease with age, thereby contributing to reduced bone formation and an increased fracture risk.

Searching for systemic factors that might contribute to this age related decline of regenerative capacity led us to investigate plasma-derived extracellular vesicles (EVs). EVs of the elderly were found to inhibit osteogenesis compared to those of young individuals. By analyzing the differences in the vesicular content Galectin-3 was shown to be reduced in elderly-derived vesicles. While overexpression of Galectin-3 resulted in an enhanced ODC of MSCs, siRNA against Galectin-3 reduced osteogenesis. Modulation of intravesicular Galectin-3 levels correlated with an altered osteo-inductive potential indicating that vesicular Galectin-3 contributes to the biological response of MSCs to EVs. By site-directed mutagenesis we identified a phosphorylation-site on Galectin-3 mediating this effect. Finally, we showed that cell penetrating peptides comprising this phosphorylation-site are sufficient to increase ODC in MSCs. Therefore, we suggest that decrease of Galectin-3 in the plasma of elderly contributes to the age-related loss of ODC.

Association between circulating galectin-3 levels and the immunological, inflammatory and nutritional parameters in patients with colorectal cancer

Galectin-3, a β-galactoside-binding lectin, exhibits pleiotropic biological functions and has a role as one of the immunological modulators. However, the associations between circulating galectin-3 and immunological, inflammatory and nutritional parameters have not yet been fully elucidated. The serum concentration of galectin-3 was examined in association with interleukin-10 (IL-10), IL-12 and IL17 production, lymphocyte stimulation, neutrophil/lymphocyte ratio (NLR), white blood cell count (WBC), C-reactive protein (CRP) and rapid turnover proteins, including retinol-binding protein (RBP), prealbumin (PA) and transferrin (TF) in 50 patients with untreated colorectal cancers. Significant increases (P<0.05) were observed in the serum galectin-3 levels in patients with untreated colorectal cancer (9.6±4.5 ng/ml) compared with the normal controls (3.2±1.6 ng/ml). Higher serum galectin-3 concentrations were observed in patients with colon cancer (11.5±4.4 ng/ml) compared to in patients with rectal cancer (8.0±4.0 ng/ml) (P=0.005). The levels of circulating galectin-3 inversely correlated with the production of IL-10 (r=-0.59, P<0.001), and IL-12 (r=-0.69, P<0.001). Galectin-3 concentration also inversely correlated with the lymphocyte stimulation assay stimulation index (r=-0.42, P=0.021). However, the level of serum galectin-3 correlated with IL-17 production (r=0.67, P<0.001). Serum galectin-3 levels exhibited significant correlations with NLR (r=0.41, P=0.009), WBC (r=0.32, P=0.035), and CRP (r=0.63, P<0.001), and statistically significant inverse correlations with RBP (r=-0.45, P=0.002), PA (r=-0.46, P=0.001) and TF (r=-0.72, P<0.001). Galectin-3 may be one of the key factors in the regulation of immunological, inflammatory and nutritional conditions.

Thiodigalactoside shows antitumour activity by beta-galactoside-binding protein and regulatory T cells inhibition in oral squamous cell carcinoma

OBJECTIVE

Thiodigalactoside (TDG), a synthetic inhibitor of β-galactoside-binding protein (β-GBP) suppresses tumour growth by inhibiting multiple cancer enhancing activities of β-GBP. Hence, we attempted to understand whether disruption of β-GBP functions and indirect inhibition of Treg cells by TDG affect the growth and establishment of oral cancer cells.

METHOD

The growth, morphology, cell cycle regulation, apoptosis induction and angiogenesis of oral cancer cell lines (SCC-4, SCC-9, SCC-25) via MACS-purified Treg cells were performed by MTT, propidium iodide (PI) staining, annexin-V-binding assay and ELISA respectively.

RESULTS

Treatment with β-GBP showed growth-promoting effects on Tregs and oral cancer cells. However, the treatment with its inhibitor TDG resulted in inhibition of Treg subsets and also decreased the frequency of IL10(+) and IL35(+) Tregs indicating its immunomodulatory effects. Additionally, TDG treatment significantly (P < 0.001) inhibited the growth of OSCC cells with a concomitant induction of apoptosis, cell cycle arrest and anti-angiogenesis.

CONCLUSION

It appears that TDG concurrently prevents many tumour-promoting effects of β-GBP in oral cancer cells possibly by Treg inhibition. This offers a preclinical proof of the concept that therapeutic targeting of β-GBP can overcome Treg -mediated tumour promotion and immunosuppression in oral cancer patients.

B-cell precursor acute lymphoblastic leukemia and stromal cells communicate through Galectin-3

The molecular interactions between B-cell precursor acute lymphoblastic leukemia (pre-B ALL) cells and stromal cells in the bone marrow that provide microenvironmentally-mediated protection against therapeutic drugs are not well-defined. Galectin-3 (Lgals3) is a multifunctional galactose-binding lectin with reported location in the nucleus, cytoplasm and extracellular space in different cell types. We previously reported that ALL cells co-cultured with stroma contain high levels of Galectin-3. We here establish that, in contrast to more mature B-lineage cancers, Galectin-3 detected in and on the ALL cells originates from stromal cells, which express it on their surface, secrete it as soluble protein and also in exosomes. Soluble and stromal-bound Galectin-3 is internalized by ALL cells, transported to the nucleus and stimulates transcription of endogenous LGALS3 mRNA. When human and mouse ALL cells develop tolerance to different drugs while in contact with protective stromal cells, Galectin-3 protein levels are consistently increased. This correlates with induction of Galectin-3 transcription in the ALL cells. Thus Galectin-3 sourced from stroma becomes supplemented by endogenous Galectin-3 production in the pre-B ALL cells that are under continuous stress from drug treatment. Our data suggest that stromal Galectin-3 may protect ALL cells through auto-induction of Galectin-3 mRNA and tonic NFκB pathway activation. Since endogenously synthesized Galectin-3 protects pre-B ALL cells against drug treatment, we identify Galectin-3 as one possible target to counteract the protective effects of stroma.

Phenotypic abnormalities in a chorea-acanthocytosis mouse model are modulated by strain background

Chorea-acanthocytosis (ChAc) is an autosomal recessive hereditary disease characterized by neurodegeneration in the striatum and acanthocytosis that is caused by mutations in the VPS13A gene. We previously produced a ChAc model mice encoding a human disease mutation with deletion of exons 60-61 in the VPS13A gene. The behavioral and pathological phenotypes of the model mice varied a good deal from individual to individual, indicating that differences between individuals may be caused by the content of a genetic hybrid 129/Sv and C57BL/6J strain background. To establish the effect of the genetic background on phenotype, we backcrossed the ChAc-model mice to different inbred strains: C57BL/6J and 129S6/Sv. Although no significant difference between ChAc-mutant mice and wild-type mice on the C57BL/6J background was observed, the ChAc-mutant mice on the 129S6/Sv showed abnormal motor function and behavior. Furthermore, we produced ChAc-mutant mice on two different inbred strains: BALB/c and FVB. Significant reduction in weight was observed in ChAc mutant mice on the FVB and 129S6 backgrounds. We found a marked increase in the osmotic fragility of red blood cells in the ChAc mutant mice backcrossed to 129S6/Sv and FVB. The phenotypes varied according to strain, with ChAc mutant mice on the FVB and 129S6 backgrounds showing remarkably abnormal motor function and behavior. These results indicate that there are modifying genetic factors of ChAc symptoms.

Towards molecular mechanisms regulating the expression of galectins in cancer cells under microenvironmental stress conditions

Galectins, a family of soluble β-galactoside-binding proteins, serve as mediators of fundamental biological processes, such as cell growth, differentiation, adhesion, migration, survival, and death. The purpose of this review is to summarize the current knowledge regarding the ways in which the expression of individual galectins differs in normal and transformed human cells exposed to various stimuli mimicking physiological and pathological microenvironmental stress conditions. A conceptual point is being made and grounded that the modulation of galectin expression profiles is a key aspect of cellular stress responses. Moreover, this modulation might be precisely regulated at transcriptional and post-transcriptional levels in the context of non-overlapping transcription factors and miRNAs specific to galectins.

Role of galectin-3 in the pathogenesis of bladder transitional cell carcinoma

Galectins constitute an evolutionary conserved family that binds to β-galactosides. There is growing evidence that galectins are implicated in essential biological processes such as cellular communication, inflammation, differentiation and apoptosis. Galectin-3 is one of the best-known galectins, which is found in vertebrates. Galectin-3 has been shown to be expressed in some cell lines and plays important roles in several physiological and pathological processes, including cell adhesion, cell activation and chemoattraction, cell cycle, apoptosis, cell growth, and differentiation. Moreover, this galectin is of interest due to its involvement in regulation of cancer. Changes in galectin-3 expression are commonly seen in cancerous and pre-cancerous conditions and galectin-3 may be involved in the regulation of cancer cell activities that contribute to tumourigenesis, cancer progression and metastasis. Finally, galectin-3 seems to be involved in cell events in tumor microenvironment, and therefore it could be considered as a target in transitional cell carcinoma therapies. This review aims to describe recent progress in understanding the role of galectin-3 in cancer biology, with emphasis on bladder tumor progression and metastasis.

Galectin Binding to Neo-Glycoproteins: LacDiNAc Conjugated BSA as Ligand for Human Galectin-3

Carbohydrate-lectin interactions are relatively weak. As they play an important role in biological recognition processes, multivalent glycan ligands are designed to enhance binding affinity and inhibitory potency. We here report on novel neo-glycoproteins based on bovine serum albumin as scaffold for multivalent presentation of ligands for galectins. We prepared two kinds of tetrasaccharides (N-acetyllactosamine and N,N-diacetyllactosamine terminated) by multi-step chemo-enzymatic synthesis utilizing recombinant glycosyltransferases. Subsequent conjugation of these glycans to lysine groups of bovine serum albumin via squaric acid diethyl ester yielded a set of 22 different neo-glycoproteins with tuned ligand density. The neo-glycoproteins were analyzed by biochemical and chromatographic methods proving various modification degrees. The neo-glycoproteins were used for binding and inhibition studies with human galectin-3 showing high affinity. Binding strength and inhibition potency are closely related to modification density and show binding enhancement by multivalent ligand presentation. At galectin-3 concentrations comparable to serum levels of cancer patients, we detect the highest avidities. Selectivity of N,N-diacetyllactosamine terminated structures towards galectin-3 in comparison to galectin-1 is demonstrated. Moreover, we also see strong inhibitory potency of our scaffolds towards galectin-3 binding. These novel neo-glycoproteins may therefore serve as selective and strong galectin-3 ligands in cancer related biomedical research.

Galectin expression in cancer diagnosis and prognosis: A systematic review

Galectins are a family of proteins that bind to specific glycans thereby deciphering the information captured within the glycome. In the last two decades, several galectin family members have emerged as versatile modulators of tumor progression. This has initiated the development and preclinical assessment of galectin-targeting compounds. With the first compounds now entering clinical trials it is pivotal to gain insight in the diagnostic and prognostic value of galectins in cancer as this will allow a more rational selection of the patients that might benefit most from galectin-targeted therapies. Here, we present a systematic review of galectin expression in human cancer patients. Malignant transformation is frequently associated with altered galectin expression, most notably of galectin-1 and galectin-3. In most cancers, increased galectin-1 expression is associated with poor prognosis while elevated galectin-9 expression is emerging as a marker of favorable disease outcome. The prognostic value of galectin-3 appears to be tumor type dependent and the other galectins require further investigation. Regarding the latter, additional studies using larger patient cohorts are essential to fully unravel the diagnostic and prognostic value of galectin expression. Furthermore, to better compare different findings, consensus should be reached on how to assess galectin expression, not only with regard to localization within the tissue and within cellular compartments but also regarding alternative splicing and genomic variations. Finally, linking galectin expression and function to aberrant glycosylation in cancer cells will improve our understanding of how these versatile proteins can be exploited for diagnostic, prognostic and even therapeutic purposes in cancer patients.

Serum galectin-3 as a potential marker for gastric cancer

Background

The identification of cancer biomarkers can advance the possibility for early detection and better monitoring of tumor progression. The aim of this study was to assess the diagnostic and prognostic value of serum galectin-3(Gal-3) in patients with gastric cancer (GC).

Material/Methods

We measured serum Gal-3 levels using ELISA method in 87 patients with GC, 53 patients with benign gastric lesions, and 51 healthy controls.

Results

Serum levels of Gal-3 in patients with GC were significantly higher than those in benign disease patients and healthy controls (P<0.001), but no difference was found between benign disease patients and healthy controls (P=0.635). Additionally, serum Gal-3 level was associated with lymph node metastasis (P=0.001) and distant metastasis (P<0.001), whereas it was not related to gender (P=0.204), age (P=0.269), tumor size (P=0.399), location (P=0.715), TNM stage (P=0.385), differentiation (P=0.135), or invasion depth (P=0.273). The Kaplan-Meier survival analysis revealed that overall survival rates in patients with high Gal-3 levels were not significantly different that those with low Gal-3 levels (P=0.099).

Conclusions

Results of the current study suggests that serum Gal-3 represents a potential diagnostic marker for patients with GC, and may be an adjunct to determine the individual prognosis of these patients.

Examination of the regulation of galectin-3 expression in cancer

Galectin-3, a member of a β-galactoside-binding protein family, is involved in normal growth development as well as cancer progression and metastasis, but the detailed mechanisms of its functions or its transcriptional regulations are not well understood. Besides, several regulatory elements such as GC box, CRE motif, AP-1 site, and NF-κB sites, the promoter of galectin-3 gene (LGALS3) contains several CpG islands that can be methylated during tumorigenesis of prostate leading to the gene silencing. Here we describe protocols for identification of galectin-3 DNA methylation, suppression of DNA methyltransferases to reactivate galectin-3 expression, and development of methylation-specific polymerase chain reaction (MS-PCR) to assess galectin-3 expression in various biological specimens such as tissue, serum, and urine samples.

Galectins in cancer: carcinogenesis, diagnosis and therapy

A major breakthrough in the field of medical oncology has been the discovery of galectins and their role in cancer development, progression and metastasis. In this review article we have condensed the results of a number of studies published over the past decade in an effort to shed some light on the unique role played by the galectin family of proteins in neoplasia, and how this knowledge may alter the approach to cancer diagnosis as well as therapy in the future. In this review we have also emphasized the potential use of galectin inhibitors or modulators in the treatment of cancer and how this novel treatment modality may affect patient outcomes in the future. Based on current pre-clinical models we believe the use of galectin inhibitors/modulators will play a significant role in cancer treatment in the future. Early clinical studies are underway to evaluate the utility of these promising agents in cancer patients.

Diagnostic and Prognostic Significance of Serum and Tissue Galectin 3 Expression in Patients with Carcinoma of the Bladder

BACKGROUND

Galectins are group of proteins found in the cytoplasm, nucleus, cell surface and extracellular matrix. Galectin 3 (Gal-3) displays pathological expression in a variety of processes such as tumorigenesis.

PATIENTS AND METHOD

70 patients classified into the control group, cystitis group, transitional cell carcinoma group, and squamous cell carcinoma group were enrolled in this study which aimed to detect the serum level and the intensity of tissue expression of Gal-3.

RESULTS

Both serum level and tissue expression of Gal-3 were statistically higher in bladder cancer patients compared to the other groups. Gal-3 level expression increased from low to high grade urothelial tumors, with a statistically significant increase of its level and expression between muscle invasive and non-muscle invasive Ta urothelial tumors.

CONCLUSION

The serum Gal-3 level is sensitive and specific for the diagnosis of bladder cancer. The prognostic significance of tissue expression is to be confirmed.

Circulating galectins -2, -4 and -8 in cancer patients make important contributions to the increased circulation of several cytokines and chemokines that promote angiogenesis and metastasis

Background:

Circulating concentrations of the cytokines interleukin-6 (IL-6), granulocyte colony-stimulating factor (G-CSF) and chemokines monocyte chemotatic protein 1 (MCP-1)/CCL2 and growth-regulator oncogene α (GROα)/chemokine C-X-C motif ligand 1 are commonly increased in cancer patients and they are increasingly recognised as important promoters, via divergent mechanisms, of cancer progression and metastasis.

Methods:

The effect of galectins-2, -4 and -8, whose circulating levels are highly increased in cancer patients, on endothelial secretion of cytokines was assessed in vitro by cytokine array and in mice. The relationship between serum levels of galectins and cytokines was analysed in colon and breast cancer patients.

Results:

Galectins-2, -4 and -8 at pathological concentrations induce secretion of G-CSF, IL-6, MCP-1 and GROα from the blood vascular endothelial cells in vitro and in mice. Multiple regression analysis indicates that increased circulation of these galectins accounts for 41∼83% of the variance of these cytokines in the sera of colon and breast cancer patients. The galectin-induced secretion of these cytokines/chemokines is shown to enhance the expression of endothelial cell surface adhesion molecules, causing increased cancer-endothelial adhesion and increased endothelial tubule formation.

Conclusion:

The increased circulation of galectins -2, -4 and -8 in cancer patients contributes substantially to the increased circulation of G-CSF, IL-6 and MCP-1 by interaction with the blood vascular endothelium. These cytokines and chemokines in turn enhance endothelial cell activities in angiogenesis and metastasis.

Galectin-3: its role in asthma and potential as an anti-inflammatory target

Galectins constitute an evolutionary conserved family that bind to β-galactosides. Increasing evidence shows that galectins are involved in many fundamental biological processes such as cellular communication, inflammation, differentiation and apoptosis. Changes in galectin-3 (Gal-3) expression are commonly seen in cancer and pre-cancerous conditions, and Gal-3 may be involved in the regulation of diverse cancer cell activities that contribute to tumourigenesis, cancer progression and metastasis. In addition, Gal-3 is a pro-inflammatory regulator in rheumatoid arthritis. Gal-3 has been shown to be involved in many aspects in allergic inflammation, such as eosinophil recruitment, airway remodeling, development of a Th2 phenotype as well as increased expression of inflammatory mediators. In an in vivo model it was shown that bronchoalveolar lavage (BAL) fluid from ovalbumin-challenged mice contained significantly higher levels of Gal-3 compared to control mice. The molecular mechanisms of Gal-3 in human asthma have not been fully elucidated. This review will focus on what is known about the Gal-3 and its role in the pathophysiological mechanisms of asthma to evaluate the potential of Gal-3 as a biomarker and therapeutic target of asthma.

Galectin 3 for the diagnosis of bladder cancer

OBJECTIVE

To evaluate serum levels of galectin-3 (G-3) in patients with bladder cancer and a control group, as a potential diagnostic and prognostic serum tumour marker.

PATIENTS AND METHODS

Between November 2012 and January 2013, 55 patients (median age 58 years) were enrolled into three groups, i.e., a control, those with transitional cell carcinoma (TCC) or those with squamous cell carcinoma (SCC). The serum G-3 level was measured the night before cystoscopy. The levels of G-3 levels were correlated with tumour type, stage and grade, and in relation to levels in normal urothelium. The results were analysed statistically using the Mann-Whitney U-test, the Kruskal-Wallis test and the receiver operating characteristic curve, as appropriate.

RESULTS

The median serum G-3 level was 100, 720 and 920 pg/mL in the control, TCC and SCC groups, respectively, with very significantly greater G-3 levels in both the TCC and SCC groups than in the control group. Patients with high-grade TCC had a statistically significantly greater serum G-3 level than those with low-grade tumours, as did those with muscle-invasive TCC than those with Ta tumours.

CONCLUSIONS

The level of G-3 can aid as a diagnostic marker in patients with either TCC or SCC of the bladder, but the prognostic significance of G-3 remains to be confirmed.

Galectin-3: a possible complementary marker to the PSA blood test

The prostate-specific antigen (PSA) test has served as a blood marker of prostate cancer (PCa), and for monitoring recurrence/metastasis in patients after therapeutic intervention. However, the applicability/reliability of the PSA test was recently questioned as it is not without challenges, in particular in men who have PCa without an elevated PSA (false negative), or in men who are disease-free with elevated levels of PSA (false positive). Galectin-3 is a tumor-associated protein; present in the seminal fluid and is a substrate for the PSA enzyme e.g., a chymotrypsin-like serine protease. We hypothesized that the cleavage status and level of galectin-3 in the prostate tissue and sera are associated with PCa. Thus, we compared galectin-3 levels obtained from sera of non-cancer urology patients to those of metastatic PCa patients. The data were confirmed by analyzing PCa tissue arrays. Here, we report that galectin-3 levels in the sera of patients with metastatic PCa were uniformly higher as compared to the non-cancer patient controls. The data suggest that galectin-3 serum level may be a useful serum complementary marker to the PSA blood test to be used for initial and follow-up PSA complimentary diagnostic/prognostic tool for recurrence in PCa patients.

Increased circulation of galectin-3 in cancer induces secretion of metastasis-promoting cytokines from blood vascular endothelium

PURPOSE

Cytokines such as interleukin (IL)-6 and granulocyte colony-stimulating factor (G-CSF) are important metastasis promoters. This study has investigated the functional significance of the increased circulation of galectin-3, a common feature in patients with cancer and in particular those with metastasis, on cytokine secretion from the blood vascular endothelium in cancer.

EXPERIMENTAL DESIGN

The effects of galectin-3 on secretion of cytokines from human microvascular lung endothelial cells were assessed in vitro by cytokine array and in vivo in mice. The consequences of galectin-3-induced cytokine secretion on endothelial cell behaviors were determined, and the relationship between the levels of circulating galectin-3 and cytokines in patients with colorectal cancer with and without metastasis was investigated.

RESULTS

Galectin-3 at pathologic concentrations found in patients with cancer induces secretion of IL-6, G-CSF, sICAM-1, and granulocyte macrophage colony-stimulating factor from blood vascular endothelial cells in vitro and in mice. These cytokines autocrinely/paracrinely interact with the vascular endothelium to increase the expressions of endothelial cell surface adhesion molecules integrinα(v)β(1), E-selectin, ICAM-1, and VCAM-1, resulting in increased cancer cell-endothelial adhesion and increased endothelial cell migration and tubule formation. In patients with metastatic colon cancer, higher serum galectin-3 levels correlated significantly with increased serum G-CSF, IL-6, and sICAM1 concentrations.

CONCLUSION

The increased circulation of galectin-3 in patients with cancer induces secretion of several metastasis-promoting cytokines from the blood vascular endothelium that enhances endothelial cell activities in metastasis. Targeting the actions of circulating galectin-3 in patients with cancer therefore represents a promising therapeutic strategy to reduce metastasis and improve survival.

Simultaneous determination of serum galectin-3 and -4 levels detects metastases in colorectal cancer patients

BACKGROUND

Development of effective ways to detect metastases is highly desirable for improving the therapeutic strategies and survival of cancer patients. Serum levels of galectin-3 and -4, two members of the galactoside-binding galectin family, have recently been reported to be markedly increased up to 31-fold in the bloodstream of colorectal cancer patients and in particular those with metastases.

RESULTS

We found that simultaneous determination of serum galectin-3 and -4 levels in a single assay provides a high specificity and sensitivity in distinguishing colorectal cancer patients without metastases from those with liver metastases. This result was partly attributed by a reciprocal relationship of serum galectin-3 and -4 levels in patients with metastases. Higher serum galectin-3/-4 levels at the time of primary tumour removal in patients who did not exhibit clinically detectable metastases were associated with a trend of a poorer patients' survival in the next 10 years.

CONCLUSION

Simultaneous determination of serum galectin-3 and -4 levels can potentially be used alone or in combination with other assessments to detect colorectal cancer metastases.

The fibrosis marker galectin-3 and outcome in the general population

OBJECTIVE

Galectin-3 is involved in fibrosis and inflammation and plays a role in heart failure, renal disease, obesity and cancer. We aimed to establish the relationship between galectin-3 and cardiovascular (CV) risk factors and mortality in the general population.

DESIGN AND SUBJECTS

This study included 7968 subjects from the Prevention of REnal and Vascular ENd-stage Disease (PREVEND) cohort, with a median follow-up of approximately 10 years. Plasma galectin-3 was measured in baseline samples.

MAIN OUTCOME MEASURES

We investigated the relationships between galectin-3 levels, demographic characteristics and risk factors of CV disease. We determined the prognostic value for all-cause, CV and cancer mortality.

RESULTS

The mean age of the population was 50 ± 13 years. Mean blood pressure was 129/74 mmHg, mean cholesterol was 5.7 ± 1.1 mmol L(-1) and median galectin-3 was 10.9 ng mL(-1) [interquartile range (IQR) 9.0-13.1]. Galectin-3 levels correlated with a wide range of risk factors of CV disease, including blood pressure, serum lipids, body mass index, renal function and N-terminal pro-B-type natriuretic peptide (P < 0.0001). We observed a strong association between galectin-3 and age. Furthermore, we found a gender interaction, with female subjects (n = 4001) having higher median galectin-3 levels (11.0 ng mL(-1) , IQR 9.1-13.4 vs. men (n = 3967) 10.7 ng mL(-1) , IQR 8.9-12.8; P < 0.0001), and galectin-3 levels in women more strongly correlated with risk factors of CV disease. After correction for the classical CV risk factors (smoking, blood pressure, cholesterol and diabetes), galectin-3 levels independently predicted all-cause mortality (hazard ratio per SD galectin-3 1.09, 95% CI 1.01-1.19; P = 0.036), but not CV and cancer mortality separately.

CONCLUSIONS

Galectin-3 is associated with age and risk factors of CV disease, with a strong gender interaction for these correlations. Galectin-3 predicts all-cause mortality in the general population.

Galectins promote the interaction of influenza virus with its target cell

Influenza virus is known to bind sialoglycans located on the surface of the host cell. In addition, recent data suggest the involvement of other molecular targets in viral reception. Of note, a high density of terminal galactose residues is created on the surface of virions because of the influenza virus' own neuraminidase activity. Thus, we suggested the possibility for an interaction of the influenza virus with galactose-binding proteins--galectins. In the present work we studied the influence of several galectins on the adhesion and further internalization of virus into the cell; six virus strains and three cell lines were studied. Chicken galectins CG-1A and -2 as well as human galectins HGal-1 and -8 promote virus binding in dose dependent manner, but they do not influence the internalization stage. Also, galectins are able to restore the ability of influenza virus to infect desialylated cells up to the level of native cells. When CG-1A in physiological concentrations was loaded onto viruses, the adhesion level was higher than in the case of on-cell loading. The effect of adhesion increase depends on the glycan structure of target-cell as well as of virus. The aggregated data suggest a promotional effect of galectins during the stage of influenza virus binding with the surface of target-cell.

Serum galectin-2, -4, and -8 are greatly increased in colon and breast cancer patients and promote cancer cell adhesion to blood vascular endothelium

PURPOSE

Adhesion of disseminating tumor cells to the blood vascular endothelium is a pivotal step in metastasis. Previous investigations have shown that galectin-3 concentrations are increased in the bloodstream of patients with cancer and that galectin-3 promotes adhesion of disseminating tumor cells to vascular endothelium in vitro and experimental metastasis in vivo. This study determined the levels of galectin-1, -2, -3, -4, -8, and -9 in the sera of healthy people and patients with colon and breast cancer and assessed the influence of these galectins on cancer-endothelium adhesion.

EXPERIMENTAL DESIGN

Serum galectins and auto-anti-MUC1 antibodies were assessed using ELISA and mucin protein (MUC1) glycan microarrays, and cancer-endothelium adhesion was determined using monolayers of human microvascular lung endothelial cells.

RESULTS

The levels of serum galectin-2, -3, -4, and -8 were significantly increased up to 31-fold in patients with cancer and, in particular, those with metastases. As previously shown for galectin-3, the presence of these galectins enhances cancer-endothelium adhesion by interaction with the Thomsen-Friedenreich (TF; Galβ1,3GalNAcα-) disaccharide on cancer-associated MUC1. This causes MUC1 cell surface polarization, thus exposing underlying adhesion molecules that promote cancer-endothelium adhesion. Elevated circulating galectin-2 levels were associated with increased mortality in patients with colorectal cancer, but this association was suppressed when anti-MUC1 antibodies with specificity for the TF epitope of MUC1 were also present in the circulation.

CONCLUSIONS

Increased circulation of several members of the galectin family is common in patients with cancer and these may, like circulating galectin-3, also be involved in metastasis promotion.

Expression of galectin-3 in pancreatic ductal adenocarcinoma

Galectin-3 influences neoangiogenesis, tumor cell adhesion, and tumor-immune-escape mechanisms. Hence, the expression of galectin-3 in pancreatic ductal adenocarcinoma (PDAC) was evaluated. Galectin-3 expression in PDAC cell lines was proven by the presence of intracellular protein and by release into the supernatant. Furthermore, galectin-3 was found in the majority of human tissue samples. Serum concentrations of galectin-3 in PDAC patients did not differ significantly from healthy donors and did not correlate with established tumor markers. In conclusion, galectin-3 is expressed in PDAC tissues suggesting a role in tumor development; however, no relationship between expression and clinical findings could be established.

Soluble IgE receptors--elements of the IgE network

Soluble isoforms of three human IgE Fc receptors, namely FcεRI, FcεRII, and galectin-3, can be found in serum. These soluble IgE receptors are a diverse family of proteins unified by the characteristic of interacting with IgE in the extracellular matrix. A truncated form of the alpha-chain of FcεRI, the high affinity IgE receptor, has recently been described as a soluble isoform (sFcεRI). Multiple soluble isoforms of CD23 (sCD23), the low affinity IgE receptor also known as FcεRII, are generated via different mechanisms of extracellular and intracellular proteolysis. The second low affinity IgE receptor, galectin-3, only exists as a secretory protein. We here discuss the physiological roles of these three soluble IgE receptors as elements of the human IgE network. Additionally, we review the potential and current use of sFcεRI, sCD23, and galectin-3 as biomarkers in human disease.

Methods for the discovery of low-abundance biomarkers for urinary bladder cancer in biological fluids

For the study of bladder cancer and the identification of respective tumor markers, blood and, in particular, urine constitute suitable sources of biological material, while both harboring their specific challenges for analytics concerning low-abundance biomarkers. Dissolved proteins and nucleic acids as well as cells and cell-bound molecules can be the analytes. In urine, exfoliated bladder tumor cells have to be identified and in blood, circulating tumor cells have to be detected among huge amounts of other cells. For the detection of both low-abundance cells and molecules, their specific enrichment prior to analysis is advantageous or even necessary. Adapted methods for the analysis of proteomes and subproteomes by 2D-gel electrophoresis, multidimensional chromatography and antibody arrays are discussed. Analysis of nucleic acid-based markers exploits the high amplification power of PCR and modified PCR combined with previous (subtransciptomes) or subsequent (microarray) enrichment to sensitively and specifically detect markers. DNA mutations, DNA-methylation status and apoptotic DNA fragments, as well as levels of ribonucleic acids including microRNAs, can be analyzed by means of these methods. Finally, the challenge of identifying circulating tumor cells and assigning them to their original tissue is critically discussed.

[Galectin expression in urological cancer. Diagnostic, prognostic and therapeutic potential]

Galectins are a family of 15 proteins. They interact with glycoproteins in both the extracellular and intracellular milieu and regulate various biological cycles including cell growth, cell differentiation, cell adhesion and apoptosis. In biomolecular studies certain patterns of expression showed a correlation with metastasis and apoptosis. Therefore, galectins could be used as potential markers for early tumour recognition, long-term prognosis and a better-founded choice of therapy. Acknowledging these possibilities this review points out the standing of galectins with all currently available data in the development and progression of renal, bladder and prostatic tumours. The expression patterns of galectin-1 and -3 have been researched extensively. For example, several studies could show a decreased expression of galectin-3 in clear renal cell carcinoma, which correlated with a poor clinical prognosis. On the contrary, patients with a bladder tumour showed an elevated serum level of galectin-3. Furthermore, in analysis of prostatic tumour tissue galectin-1 was found to be an independent predictor of a PSA relapse. In addition, pathological patterns of galectin expression could be detected in non-urological malignancies such as breast cancer. Though all findings indicate a future significance of galectins as markers of urological malignancies with clinical relevance, more research will be necessary to particularly assess the evolutional-dependent function of galectins in the process of tumourigenesis.