Loss of galectin-3 expression correlates with clear cell renal carcinoma progression and reduced survival

Galectin-3: action and clinical utility in chronic kidney disease

Chronic kidney disease is a significant cause of morbidity and mortality worldwide. In recent years, Galectin-3 has been put forward as a potential biomarker of chronic kidney disease progression. This review aims to assess the clinical utility of Galectin-3 in various pathological processes leading up to chronic kidney disease such as diabetes and lupus nephritis. We conducted a systematic search on PubMed from inception to September 2023, using the search term ("Galectin-3" OR "gal-3") AND ("renal" OR "kidney"). Galectin-3 has been shown to be both pro-fibrotic and protective against renal fibrosis through various mechanisms such as apoptotic body clearance and modulation of the Wnt pathway. Studies have found associations between raised Galectin-3, incidence and progression of chronic kidney disease. In lupus nephritis, Galectin-3 may serve as a biomarker for lupus nephritis activity. Although Galectin-3 inhibits cystogenesis, there is no correlation between total kidney volume and Galectin-3 in polycystic kidney disease. The role of Galectin-3 in staging and prognostication of renal cell carcinoma is yet to be determined. Galectin-3 has potential in predicting chronic kidney disease progression, in combination with other biomarkers. However, more trials are required given that present studies demonstrate conflicting results on the relationship between Galectin-3 and clinical outcomes in chronic kidney disease patients of varying aetiologies.

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).

Development of Galectin-3 Targeting Drugs for Therapeutic Applications in Various Diseases

Galectin-3 (Gal3) is one of the most studied members of the galectin family that mediate various biological processes such as growth regulation, immune function, cancer metastasis, and apoptosis. Since Gal3 is pro-inflammatory, it is involved in many diseases that are associated with chronic inflammation such as cancer, organ fibrosis, and type 2 diabetes. As a multifunctional protein involved in multiple pathways of many diseases, Gal3 has generated significant interest in pharmaceutical industries. As a result, several Gal3-targeting therapeutic drugs are being developed to address unmet medical needs. Based on the PubMed search of Gal3 to date (1987-2023), here, we briefly describe its structure, carbohydrate-binding properties, endogenous ligands, and roles in various diseases. We also discuss its potential antagonists that are currently being investigated clinically or pre-clinically by the public and private companies. The updated knowledge on Gal3 function in various diseases could initiate new clinical or pre-clinical investigations to test therapeutic strategies, and some of these strategies could be successful and recognized as novel therapeutics for unmet medical needs.

Galectin-3 in prostate cancer and heart diseases: a biomarker for these two frightening pathologies?

Galectin-3 (Gal-3) belongs to galectin protein family, a type of β-galactose-binding lectin having more than one evolutionarily conserved domain of carbohydrate recognition. Gal-3 is mainly located in the cytoplasm, but it also enters the nucleus and is secreted into the extracellular environment and biological fluids such as urine, saliva, and serum. It plays an important role in many biological functions, such as angiogenesis, apoptosis, cell differentiation, cell growth, fibrosis, inflammation, host defense, cellular modification, splicing of pre-mRNA, and transformation. Many previous studies have shown that Gal-3 can be used as a diagnostic or prognostic biomarker for heart ailments, kidney diseases, and other major illnesses including cancer. Moreover, it may also play a major role in risk stratification in different diseases, and in this review, we have summarized the potential roles and application of Gal-3 as diagnostic, prognostic, and risk stratifying biomarker from previously reported studies in heart diseases and cancer, with special emphasis on prostate cancer.

Distinct cholangiocarcinoma cell migration in 2D monolayer and 3D spheroid culture based on galectin-3 expression and localization

Introduction

Cholangiocarcinoma (CCA) is difficult to cure due to its ineffective treatment and advanced stage diagnosis. Thoroughly mechanistic understandings of CCA pathogenesis crucially help improving the treatment success rates. Using three-dimensional (3D) cell culture platform offers several advantages over a traditional two-dimensional (2D) culture as it resembles more closely to in vivo tumor.

Methods

Here, we aimed to establish the 3D CCA spheroids with lowly (KKU-100) and highly (KKU-213A) metastatic potentials to investigate the CCA migratory process and its EMT-associated galectin-3 in the 3D setting.

Results and discussion

Firstly, the growth of lowly metastatic KKU-100 cells was slower than highly metastatic KKU-213A cells in both 2D and 3D systems. Hollow formation was observed exclusively inside the KKU-213A spheroids, not in KKU-100. Additionally, the migration activity of KKU-213A cells was higher than that of KKU-100 cells in both 2D and 3D systems. Besides, altered expression of galectin-3 were observed across all CCA culture conditions with substantial relocalization from inside the 2D cells to the border of spheroids in the 3D system. Notably, the CCA migration was inversely proportional to the galectin-3 expression in the 3D culture, but not in the 2D setting. This suggests the contribution of culture platforms to the alternation of the CCA cell migration process.

Conclusions

Thus, our data revealed that 3D culture of CCA cells was phenotypically distinct from 2D culture and pointed to the superiority of using the 3D culture model for examining the CCA cellular mechanisms, providing knowledges that are better correlated with CCA phenotypes in vivo.

Predictive importance of galectin-3 for recurrence of non-small cell lung cancer

OBJECTIVE

The predictive importance of galectin-3 in non-small cell lung cancer (NSCLC) has not been elucidated. We examined whether galectin-3 could serve as a predictor for tumor recurrence in NSCLC.

METHODS

In 42 consecutive patients with NSCLC who underwent radical resection, galectin-3 expression in tumor cells was examined by immunohistochemistry. Galectin-3 levels in serum were assessed before surgery and 1 month after surgery by enzyme-linked immunosorbent assays.

RESULTS

Higher expression of galectin-3 in tumor cells was associated significantly with lymphatic invasion (p = 0.049) and tumor recurrence (p = 0.001). The Kaplan-Meier curves for relapse-free survival after radical resection showed that patients with high expression of galectin-3 had significantly shorter relapse-free survival than those with low expression of galectin-3 (p < 0.001). The serum level of galectin-3 was not reduced after radical resection, and there was no significant correlation between the serum level of galectin-3 and recurrence.

CONCLUSIONS

Galectin-3 expression in tumor cells could serve as a predictive factor for recurrence, but serum level of galectin-3 is not useful for predicting NSCLC recurrence.

Hypoxia‑induced galectin‑3 enhances RhoA function to activate the motility of tumor cells in non‑small cell lung cancer

Galectin-3 plays crucial roles in tumor progression. However, in non-small cell lung cancer (NSCLC), it remains unclear whether the hypoxic tumor microenvironment enhances galectin-3-induced cell motility. We investigated galectin-3 expression in NSCLC cells under hypoxia, and the possible molecular mechanisms by which galectin-3 influences tumor aggressiveness. Galectin-3 levels in NSCLC cell lines under hypoxia were assessed using reverse transcription PCR and western blotting. To clarify the role of endogenous galectin-3, the effect of galectin-3 knockdown in NSCLC cells was investigated using scratch and invasion assays. The expression and clinicopathological significance of galectin-3 in 57 patients with pN0M0 invasive pulmonary adenocarcinoma were investigated by immunohistochemistry. Both mRNA and protein levels of galectin-3 in the NSCLC cell lines A549 and LK-2 were upregulated by hypoxia. As revealed by scratch and invasion assays, the cell migratory and invasive activities were significantly increased under hypoxia, but were reduced by galectin-3 knockdown. Notably, addition of galectin-3 to the media did not improve the cell motility impaired by galectin-3 knockdown. To clarify the role of endogenous galectin-3 in the enhancement of tumor cell motility under hypoxia, we focused on the function of RhoA. RhoA level in the plasma membrane, but not in the cytoplasm, was increased under hypoxia and decreased by galectin-3 knockdown. RhoA activity was significantly enhanced under hypoxia and effectively inhibited by galectin-3 knockdown. In patients with pN0M0 invasive pulmonary adenocarcinoma, higher galectin-3 expression on tumor cells was significantly associated with tumor cell invasion into microvessels and tumor recurrence after surgery. These data demonstrate that in NSCLC cells under hypoxia, upregulated galectin-3 levels increase the localization of RhoA to the plasma membrane, thus enhancing RhoA activity, which is associated with aggressive cell motility. In pN0M0 invasive pulmonary adenocarcinoma, galectin-3 is a potential biomarker for predicting tumor recurrence after radical surgery.

Expression of galectin-1 and galectin-3 in renal cell carcinoma; immunohistochemical study

BACKGROUND AND AIMS

Galectins comprise a large family of calcium independent lectins. Galectin-1 and galectin-3 contribute to neoplastic transformation, angiogenesis, and tumor metastasis in some cancers. This study aimed at studying the immunohistochemical expression of both galectin-1 and galectin-3 in renal cell carcinoma (RCC) variants and detecting the possible association of galectins with various clinicopathological parameters.

MATERIALS AND METHODS

Sections from 67 formalin-fixed paraffin-embedded tissue blocks of RCC variants were stained with galectin-1 and galectin-3. Expression was assessed in tumor tissue and adjacent renal parenchyma and was correlated with clinicopathological criteria.

RESULTS

In apparently normal renal parenchyma adjacent to tumor tissue, galectin-1 was expressed in 27 (40.2%) of specimens in renal tubules and glomeruli, while 34 (50.7%) of specimens showed galectin-3 expression in renal tubules sparing glomeruli. In tumor tissue, galectin-1 showed high expression in 47 (70.1%) and low expression in 20 (29.9%) of specimens. Galectin-3 had high expression in 15 (22.4%) and low expression in 52 (77.6%) of specimens. Significant association was detected between expression of galectin-1 and galectin-3 and the type of RCC (P = 0.032) and (P = 0.006), respectively. Significant inverse association was detected between the expression of galectin-3 and the presence of tumor haemorrhage and necrosis (P = 0.014) and (P = 0.039), respectively.

CONCLUSION

Galectin-1 and galectin-3 are overexpressed in RCC with different percentage in different subtypes. Galactin-1expression is more in tumor tissue than surrounding renal parenchyma suggesting that it has a carcinogenic role. Galectin-1 and galectin-3 overexpression in chromophobe RCC suggests that they may have diagnostic role.

The Role of Galectins in Cervical Cancer Biology and Progression

Cervical cancer is one of the malignant tumors with high incidence and high mortality among women in developing countries. The main factors affecting the prognosis of cervical cancer are the late recurrence and metastasis and the effective adjuvant treatment, which is radiation and chemotherapy or combination therapy. Galectins, a family containing many carbohydrate binding proteins, are closely involved in the occurrence and development of tumor. They are involved in tumor cells transformation, angiogenesis, metastasis, immune escape, and sensitivity against radiation and chemotherapy. Therefore, galectins are deemed as the targets of multifunctional cancer treatment. In this review, we mainly focus on the role of galectins, especially galectin-1, galectin-3, galectin-7, and galectin-9 in cervical cancer, and provide theoretical basis for potential targeted treatment of cervical cancer.

Intranuclear accumulation of galectin-3 is an independent prognostic factor for patients with distal cholangiocarcinoma

Galectin-3 has been reported to be associated with the prognosis of patients with various malignancies; however, it has not yet been investigated in patients with extrahepatic cholangiocarcinoma (EHCC). Expression of galectin-3 was retrospectively examined in 58 patients with EHCC: 21 with perihilar cholangiocarcinoma and 37 with distal cholangiocarcinoma (DCC). The Cox proportional hazard model was used to identify independent prognostic factors. Intranuclear accumulation of galectin-3 (gal-3-INA) was associated with poorer overall survival (OS) in all patients (P=0.003), as well as in patients with DCC (P=0.004). Patients with gal-3-INA also exhibited a poorer disease-free survival (DFS) than those without gal-3-INA in all patients with EHCC (P<0.001), and in patients with DCC (P<0.001). Gal-3-INA was an independent prognostic factor of OS and DFS in all patients [OS: Hazard ratio (HR), 4.470; 95% confidence interval (CI), 1.759–11.357; P=0.002; and DFS: HR, 5.116; 95% CI, 2.025–12.925; P=0.001]. Gal-3-INA was also an independent prognostic factor in patients with DCC (OS: HR, 2.979; 95% CI, 1.035–8.570; P=0.043; and DFS: HR, 6.773; 95% CI, 1.558–29.439; P=0.011). In the analysis of patients with DCC, the number of patients with high galectin-3 expression (P=0.038), recurrence (P<0.001), distant metastases (P<0.001), R0 status (P=0.029) or microscopic vascular invasion (P=0.019) was significantly higher in the gal-3-INA-positive group than in the gal-3-INA-negative group. In conclusion, gal-3-INA was identified as a strong prognostic factor for OS and DFS in patients with DCC.

Glycolipids and Lectins in Endocytic Uptake Processes

A host of endocytic processes has been described at the plasma membrane of eukaryotic cells. Their categorization has most commonly referenced cytosolic machinery, of which the clathrin coat has occupied a preponderant position. In what concerns intra-membrane constituents, the focus of interest has been on phosphatidylinositol lipids and their capacity to orchestrate endocytic events on the cytosolic leaflet of the membrane. The contribution of extracellular determinants to the construction of endocytic pits has received much less attention, depite the fact that (glyco)sphingolipids are exoplasmic leaflet fabric of membrane domains, termed rafts, whose contributions to predominantly clathrin-independent internalization processes is well recognized. Furthermore, sugar modifications on extracellular domains of proteins, and sugar-binding proteins, termed lectins, have also been linked to the uptake of endocytic cargoes at the plasma membrane. In this review, we first summarize these contributions by extracellular determinants to the endocytic process. We thus propose a molecular hypothesis - termed the GL-Lect hypothesis - on how GlycoLipids and Lectins drive the formation of compositional nanoenvrionments from which the endocytic uptake of glycosylated cargo proteins is operated via clathrin-independent carriers. Finally, we position this hypothesis within the global context of endocytic pathway proposals that have emerged in recent years.

Antitumor effects of galectin-3 inhibition in human renal carcinoma cells

Galectins are thought to be prognosticators for survival in renal cell cancer. However, the biological activity of galectin-3 (Gal-3) in renal carcinoma cells is still debated. In this study, immunohistochemical staining confirmed a high expression of Gal-3 in tumor tissue from renal cell carcinoma. Critically, Gal-3 expression was related to tumor cell differentiation. Consistent with Gal-3 expression in renal cell cancer, strong expression of Gal-3 was also observed in several renal tumor cell lines but not in normal renal cells. A Gal-3 high-expression cell line Caki-1 was chosen to study the biological activity of Gal-3. Using short hairpin RNA method, Gal-3 expression in Caki-1 cells was knocked down. We evidenced that Gal-3 knockdown inhibited cell proliferation and invasion, induced Caspase-3-dependent apoptosis and arrested cell cycle at G1 phase. Mechanically, Cyclin D1 expression decreased, but p27 increased after Gal-3 knockdown. Taken together, these results suggest that Gal-3 is related to the development of renal cell cancer and could serve as a target to therapy renal cell cancer.

Galectin-3 as a Potential Target to Prevent Cancer Metastasis

Interactions between two cells or between cell and extracellular matrix mediated by protein–carbohydrate interactions play pivotal roles in modulating various biological processes such as growth regulation, immune function, cancer metastasis, and apoptosis. Galectin-3, a member of the β-galactoside-binding lectin family, is involved in fibrosis as well as cancer progression and metastasis, but the detailed mechanisms of its functions remain elusive. This review discusses its structure, carbohydrate-binding properties, and involvement in various aspects of tumorigenesis and some potential carbohydrate ligands that are currently investigated to block galectin-3 activity.

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.

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.

Galectin-1 and Galectin-3 mRNA expression in renal cell carcinoma

Background

Galectins are known to regulate cell differentiation and growth as well as cell adhesion and apoptosis. Galectins have been discussed as possible prognosticators for survival in renal cell cancer (RCC) and other urological tumors. They might also play an emerging role as possible new marker-proteins for RCC. In this study, we analyzed the expression of galectin-1 and galectin-3 mRNA in order to further investigate their clinical significance in RCC.

Methods

Tissue samples were obtained from 106 patients undergoing surgery for RCC. The expression of galectin-1 and galectin-3 mRNA in normal kidney and corresponding cancer tissue was analyzed using quantitative real time PCR. Differences in expression levels of paired tissue samples were assessed using paired two-sample tests. Associations of relative mRNA expression levels in tumor tissues with clinical findings were analyzed using univariate logistic regression.

Results

The expression of galectin-1 (p < 0.001) and -3 (p < 0.001) mRNA were significantly higher in RCC when compared to the adjacent normal kidney tissue. For clear cell RCC, an association of male gender with higher galectin-1 and galectin-3 mRNA expression (p = 0.054, p = 0.034) was detected. For all RCCs, galectin-1 mRNA expression failed to show a significant association with advanced disease as well as a higher rate of lymph node metastases (p = 0.058, p = 0.059).

Conclusion

The mRNA expression of galectin-1 and galectin-3 is significantly increased in RCC cancer tissue. The higher mRNA expression in tumor tissue of male patients raises the question of a functional connection between galectins and the higher prevalence of RCC in men. Associations with advanced disease might lead to new ways of identifying patients at higher risk of recurrent disease and might even facilitate early metastasectomy with curative intent.

Galectin-3 in cancer

Galectin-3 (Gal-3) plays important roles in cell proliferation, adhesion, differentiation, angiogenesis and apoptosis in normal and pathologic tissues. Accumulated evidences indicate that Gal-3 is closely involved in tumor cell transformation, migration, invasion and metastasis. In this review, the associations of the expression and localization of Gal-3 as well as its potential action mechanism in tumorigenesis in a variety of cancers were summarized and concluded. Gal-3 is gaining its attraction as a potential new biomarker for the diagnosis, treatment and prognosis of certain tumors.

Higher bone marrow LGALS3 expression is an independent unfavorable prognostic factor for overall survival in patients with acute myeloid leukemia

Alterations of galectin-3 expression are often seen in cancers and may contribute to tumorigenesis, cancer progression, and metastasis. The studies concerning clinical implications of galectin-3 expression in patients with acute myeloid leukemia (AML) are scarce. We investigated the expression of LGALS3, the gene encoding galectin-3, in the bone marrow (BM) mononuclear cells from an original cohort comprising 280 adults with primary non-acute promyelocytic leukemia. Higher LGALS3 expression was closely associated with older age, French-American-British M4/M5 subtypes, CD14 expression on leukemic cells, and PTPN11 mutation, but negatively correlated with CEBPA mutation and FLT3-ITD. Compared with patients with lower LGALS3 expression, those with higher expression had lower complete remission rates, higher primary refractory rates, and shorter overall survival. This result was validated in an independent validation cohort. A scoring system incorporating higher LGALS3 expression and 8 other risk factors, including age, white blood cell count, cytogenetics, and gene mutations, into survival analysis proved to be very useful to stratify patients with AML into different prognostic groups (P < .001). In conclusion, BM LGALS3 expression may serve as a new biomarker to predict clinical outcome in patients with AML, and galectin-3 may serve as a potential therapeutic target in those patients with higher expression of this protein.

Galectin-3 expression in prostate cancer and benign prostate tissues: correlation with biochemical recurrence

BACKGROUND

Galactin-3 is a cell adhesion molecule involved in tumor progression. Our aim was to examine Gal-3 expression in tumor, benign tissue adjacent to the tumor (adjacent-benign) and benign prostate specimens and correlated it with biochemical recurrence.

MATERIALS AND METHODS

Tissue microarrays were prepared from 83 tumor, 78 adjacent-benign and 75 benign tissues obtained from 83 patients undergoing prostatectomy for clinically localized prostate cancer. Tissues were stained using a Gal-3 antibody and immunohistochemistry. The staining was graded between 0 and 300 depending upon staining intensity and the area of staining. In 37 patients on whom there was follow-up (Mean: 57.8 months; Median: 68 months), staining intensity was correlated with biochemical recurrence.

RESULTS

Gal-3 showed both nuclear and cytoplasmic localization in benign, adjacent-benign and tumor tissues. Median Gal-3 staining scores significantly decreased from benign (192.5) to adjacent-benign (148.8 p = 0.007) and to tumor (108.8; p < 0.0001) tissues. In univariate analysis, age (p = 0.028), Gleason sum (p = 0.007), T stage (p = 0.011), seminal vesicle invasion (p = 0.009), pre-operative prostate-specific antigen (p = 0.045) and Gal-3 staining in tumor tissues (0.018) significantly correlated with biochemical recurrence. In multivariate analysis, Gal-3 expression in tumor (p = 0.04), adjacent-benign (p = 0.037) and benign (p = 0.005) tissues significantly correlated with biochemical recurrence. Gal-3 staining in tumor tissues had 91.7 % sensitivity, 64 % specificity and 73 % accuracy in predicting biochemical recurrence.

CONCLUSIONS

This is the first study that showed a decreasing gradient of Gal-3 expression in benign, adjacent-benign and tumor tissues. Gal-3 expression may be useful in predicting biochemical recurrence.

Changes in the expression and subcellular distribution of galectin-3 in clear cell renal cell carcinoma

Background

Clear cell renal cell carcinoma, a solid growing tumor, is the most common tumor in human kidney. Evaluating the usefulness of β-galactoside binding galectin-3 as a diagnostic marker for this type of cancer could open avenues for preventive and therapeutic strategies by employing specific inhibitors of the lectin. To study a putative correlation between the extent of galectin-3 and the development of clear cell renal cell carcinoma, we monitored the quantity and distribution of this lectin in tissue samples from 39 patients.

Methods

Galectin-3 concentrations in normal, intermediate and tumor tissues were examined by immunofluorescence microscopy and on immunoblots with antibodies directed against galectin-3 and renal control proteins. The cell nuclei were isolated to determine quantities of galectin-3 that were transferred into this compartment in normal or tumor samples.

Results

Immunofluorescence data revealed a mosaic pattern of galectin-3 expression in collecting ducts and distal tubules of normal kidney. Galectin-3 expression was significantly increased in 79% of tumor samples as compared to normal tissues. Furthermore, we observed an increase in nuclear translocation of the lectin in tumor tissues.

Conclusions

Our data indicate that changes in the cellular level of galectin-3 correlate with the development of clear cell renal cell carcinoma, which is in line with previously published data on this specific type of tumor. In most of these studies the lectin tends to be highly expressed in tumor tissues. Furthermore, this study suggests that the increase in the proportion of galectin-3 affects the balance from a cytosolic distribution towards translocation into the nucleus.

Decreased galectin-8 is a strong marker for recurrence in urothelial carcinoma of the bladder

OBJECTIVE

To investigate galectin-8 expression patterns in normal urothelium and bladder cancer specimens and to elucidate its prognostic value.

MATERIALS AND METHODS

162 samples of non-muscle-invasive transitional cell carcinoma, 25 samples of muscle-invasive transitional cell carcinoma and 10 samples of normal urothelium were investigated by immunohistochemistry using tissue microarrays. Complete patient and tumor characteristics were compared with galectin-8 staining patterns. The likelihood of tumor recurrence and progression was analyzed based on a 3-year follow-up.

RESULTS

Loss of galectin-8 was associated with the likelihood of tumor recurrence in univariate (p < 0.05) and multivariate analyses (p < 0.01). No significance was observed for tumor progression. Patients whose specimens showed weak galectin-8 expression had a shorter recurrence-free interval (42 vs. 12 months; p < 0.01, log-rank test). All of the 10 normal urothelium samples showed high galectin-8 expression. Decreased staining was found to be associated with higher tumor stages and grades (p < 0.0001, one-way ANOVA). A significant difference was found comparing normal urothelium with any tumor stage (p < 0.01), pTa vs. pT1 tumors (p < 0.05) and non-muscle-invasive vs. muscle-invasive tumors (p < 0.0001).

CONCLUSIONS

Loss of galectin-8 might be an early step in the development of malignant lesions of the bladder and is a significant independent predictor of recurrence.

Galectin-3 expression in uterine endometrioid adenocarcinoma: comparison of staining in conventional tumor glands and in areas of MELF pattern myometrial invasion

Endometrioid adenocarcinoma (EAC) of the uterus can show varying patterns of invasion, 1 of which, "MELF," is characterized by the presence of microcystic, elongated, and fragmented glands. However, at present, little is known of the functional alterations in neoplastic cells that are associated with the different patterns of myometrial invasion, including those in MELF. Galectin-3 is a widely distributed and multifunctional carbohydrate binding protein that has been shown to influence many aspects of tumor development and progression, but there are limited and conflicting data regarding galectin-3 expression in EAC. In this study, galectin-3 immunoreactivity was investigated in 22 EACs with specific comparison of staining in the "conventional" endometrioid-type tumor glands and in areas exhibiting MELF pattern invasion. Cytoplasmic galectin-3 was present in all tumors although <50% of cells were stained in approximately one-third of the cases. Nuclear staining was evident in 11 cases, but usually only in a small proportion of cells. The neoplastic epithelium within MELF areas showed a consistent reduction in protein expression, often contrasting with the adjacent galectin-3-positive conventional glands and reactive stromal cells. Conversely, intravascular tumor foci often showed cytoplasmic and nuclear galectin-3 immunoreactivity. The microanatomical variation in galectin-3 expression in EAC suggests that there are localized functional alterations in the neoplastic epithelium and the surrounding stroma during the invasive process. As MELF pattern invasion is associated with the loss of galectin-3 expression, there may be implications for the use of galectin inhibitors in the treatment of endometrial carcinomas and other malignancies.

Maspin protein expression correlates with tumor progression in non-muscle invasive bladder cancer

Maspin is a 42-kDa protein that belongs to the family of serine protease inhibitors. It is involved in various physiological processes. In cancer tissue, Maspin was found to influence angiogenesis, tumor growth, metastasis and the prognosis of tumor patients. This study was performed to analyze the involvement of Maspin in transitional cell carcinoma of the bladder as well as its prognostic impact in a large patient cohort. Specimens from 162 non-muscle invasive bladder cancer patients (pTa, 91; pT1, 71) treated by transurethral resection with a minimum 3-year follow-up (median 58.5 months) were included in the present investigation. Tissue microarrays were constructed, and the specimens were immunohistochemically stained for Maspin protein expression. Each tissue specimen was assessed on a staining scale ranging from 0 (no staining) to 300 (strong staining) and correlated with various clinicopathological parameters. Maspin protein expression predicted progression with a sensitivity of 95% and a specificity of 70% (p<0.001). In predicting recurrence, Maspin staining showed 52% sensitivity and 67% specificity (p<0.05). Kaplan-Meier analyses were performed, and a low Maspin protein expression was correlated with a higher incidence of tumor progression (p<0.0001). However, expression levels of Maspin protein did not distinguish between pTa and pT1 specimens. Multivariate analyses indicated Maspin expression as an independent factor for predicting progression (p<0.0001) and recurrence (p<0.05). The present results suggest that the Maspin protein expression is an independent prognostic indicator for predicting recurrence and progression to muscle invasive disease. This study further emphasizes a possible clinical role of this novel tumor suppressor gene in transitional cell carcinoma of the bladder.

[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.

Promoter methylation in prostate cancer and its application for the early detection of prostate cancer using serum and urine samples

Prostate cancer is the second most common cancer and the second leading cause of cancer death in men. However, prostate cancer can be effectively treated and cured, if it is diagnosed in its early stages when the tumor is still confined to the prostate. Combined with the digital rectal examination, the PSA test has been widely used to detect prostate cancer. But, the PSA screening method for early detection of prostate cancer is not reliable due to the high prevalence of false positive and false negative results. Epigenetic alterations including hypermethylation of gene promoters are believed to be the early events in neoplastic progression and thus these methylated genes can serve as biomarkers for the detection of cancer from clinical specimens. This review discusses DNA methylation of several gene promoters during prostate carcinogenesis and evaluates the usefulness of monitoring methylated DNA sequences, such as GSTP1, RASSF1A, RARβ2 and galectin-3, for early detection of prostate cancer in tissue biopsies, serum and urine.