Clinicopathological significance of decreased galectin-3 expression and the long-term prognosis in patients with breast cancer

Multifaceted roles of Galectins: from carbohydrate binding to targeted cancer therapy

Galectins play pivotal roles in cellular recognition and signaling processes by interacting with glycoconjugates. Extensive research has highlighted the significance of Galectins in the context of cancer, aiding in the identification of biomarkers for early detection, personalized therapy, and predicting treatment responses. This review offers a comprehensive overview of the structural characteristics, ligand-binding properties, and interacting proteins of Galectins. We delve into their biological functions and examine their roles across various cancer types. Galectins, characterized by a conserved carbohydrate recognition domain (CRD), are divided into prototype, tandem-repeat, and chimera types based on their structural configurations. Prototype Galectins contain a single CRD, tandem-repeat Galectins contain two distinct CRDs linked by a peptide, and the chimera-type Galectin-3 features a unique structural arrangement. The capacity of Galectins to engage in multivalent interactions allows them to regulate a variety of signaling pathways, thereby affecting cell fate and function. In cancer, Galectins contribute to tumor cell transformation, angiogenesis, immune evasion, and metastasis, making them critical targets for therapeutic intervention. This review discusses the multifaceted roles of Galectins in cancer progression and explores current advancements in the development of Galectin-targeted therapies. We also address the challenges and future directions for integrating Galectin research into clinical practice to enhance cancer treatment outcomes. In brief, understanding the complex functions of Galectins in cancer biology opens new avenues for therapeutic strategies. Continued research on Galectin interactions and their pathological roles is essential for developing effective carbohydrate-based treatments and improving clinical interventions for cancer patients.

Advances in immunotherapy for breast cancer and feline mammary carcinoma: From molecular basis to novel therapeutic targets

The role of inflammation in cancer is a topic that has been investigated for many years. As established, inflammation emerges as a defining characteristic of cancer, presenting itself as a compelling target for therapeutic interventions in the realm of oncology. Controlling the tumor microenvironment (TME) has gained paramount significance, modifying not only the effectiveness of immunotherapy but also modulating the outcomes and prognoses of standard chemotherapy and other anticancer treatments. Immunotherapy has surfaced as a central focus within the domain of tumor treatments, using immune checkpoint inhibitors as cancer therapy. Immune checkpoints and their influence on the tumor microenvironment dynamic are presently under investigation, aiming to ascertain their viability as therapeutic interventions across several cancer types. Cancer presents a significant challenge in humans and cats, where female breast cancer ranks as the most prevalent malignancy and feline mammary carcinoma stands as the third most frequent. This review seeks to summarize the data about the immune checkpoints cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), lymphocyte activation gene-3 (LAG-3), programmed cell death protein-1 (PD-1), V-domain Ig suppressor of T cell activation (VISTA), and T-cell immunoglobulin and mucin domain 3 (TIM-3) respective ongoing investigations as prospective targets for therapy for human breast cancer, while also outlining findings from studies reported on feline mammary carcinoma (FMC), strengthening the rationale for employing FMC as a representative model in the exploration of human breast cancer.

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.

The Expression of Galectin-3 in Tumor and Cancer-Associated Fibroblasts in Invasive Micropapillary Breast Carcinomas: Relationship with Clinicopathologic Parameters

Objective

Galectin-3 affects tumor progression and cell surface polarization by expressing from the tumor and cancer-associated fibroblasts (CAFs). Therefore, it may have a role on micropapillary carcinomas (IMPC), which have characteristic morphological features. The aim was to investigate the expression levels of Galectin-3 within tumor and peritumoral CAFs in IMPC, and to compare with expression in invasive ductal carcinomas (IDC).

Materials and Methods

Hematoxylin and Eosin-stained preparations of resection materials examined between 2010-2016 were re-evaluated. Thirty-four IMPC cases and 34 IDC cases with similar molecular subtype distribution to IMPC were compared. Galectin-3 levels were evaluated with a calculated H-score in tumor and semi-quantitatively in CAFs.

Results

While tumoral Galectin-3 expression levels were higher in IMPCs compared to IDCs, there was no difference for Galectin-3 expression in CAFs between the two histologic types. However, there was no significant relationship between tumoral Galectin-3 expression and clinicopathological parameters in IMPCs. When the subjects were divided into two groups, depending on their Galectin-3 status regardless of histological types, the loss of Galectin-3 expression in tumor was found to be related to larger tumor size/advanced pT stage and a greater number of metastatic nodes. Additionally, expression of Galectin-3 in CAFs was found to be associated with distant metastasis.

Conclusion

IMPC showed prominent Galectin-3 expression in tumor compared to IDC. However, independent from the histological type, whereas the loss of Galectin-3 expression in tumor showed an association with larger tumor size and higher number of metastatic axillary lymph nodes, the presence of Galectin-3 expression in CAFs showed an association with distant metastasis.

The expression of Galectin-3 in breast cancer and its association with metastatic disease: a systematic review of the literature

Breast cancer is the most common form of cancer and the second highest cause of cancer mortality in female patients. The significance of the expression of Galectin-3 has been correlated with various malignancy types and in data from several research papers, the expression of Galectin-3 has been associated with the progression and metastasis of breast cancer. In the present study, the authors' goal is to identify whether the expression of Galectin-3 in breast cancer can be associated with the presence and/or recurrence of a metastatic disease. Both Scopus and PubMed databases were utilized, by inputting the following combination of keywords: (((Breast) AND Metastasis)) AND ((Galectin 3) OR Galectin-3). The time of publication and text availability were not considered when searching the databases and all relevant articles in English were initially accepted. We included one case-control study, three retrospective case studies and one retrospective cohort study. In two of the included studies, the levels in concentration of Galectin-3 were not correlated with a significant difference in prognosis. In two studies, the lacking in expression of Galectin-3 was associated with a worse prognosis and in one of the studies selected, the elevated levels of Galectin-3 were correlated with recurrence of disease in triple negative breast cancer cases. For most of the studies selected for this review, the results were contradictory in regard to the role of Galectin-3 for prognosis and metastatic potential in female breast cancer patients. It is still unclear, whether Galectin-3 can be used as a prognostic marker for advanced breast cancer disease.

DMBT1 suppresses cell proliferation, migration and invasion in ovarian cancer and enhances sensitivity to cisplatin through galectin-3/PI3k/Akt pathway

Ovarian cancer (OC) is one of the most common gynaecologic malignancies. Deleted in malignant brain tumors 1 (DMBT1) was considered as a tumour suppressor in multiple cancers, but there have been no systemic profiling studies of DMBT1 in OC until now. The aim of this study is to explore the role and the potential mechanism of DMBT1 in OC. mRNA levels and protein expressions of corresponding genes were detected by quantitative real-time polymerase chain reaction and western blot. Cell proliferation was detected by CCK-8 assay and cell colony formation. Cell migration and invasion were detected by wound healing and transwell assay. The combination between DMBT1 and galectin-3 was demonstrated by immunoprecipitation. We demonstrated that DMBT1 was downregulated in OC cell lines, especially SKOV3 cells. Overexpression of DMBT1 significantly inhibited cell proliferation, colony formation, migration and invasion, as well as decreased Matrix Metalloproteinase-2 (MMP-2) and MMP-7. DMBT1 caused a reduction of cell viability by treatment with cisplatin. Immunoprecipitation assay revealed a combination between DMBT1 and galectin-3. DMBT1 could decrease the expression of galectin-3 and inhibit the phosphorylation of PI3K and AKT, while overexpression of galectin-3 reversed this effect. In summary, DMBT1 might inhibit the progression of OC and improve the sensitivity of SKOV3 cells to cisplatin through galectin-3/PI3K/AKT pathway, giving a new insight into the role of DMBT1 in OC and enriching the potential strategies for OC treatment. SIGNIFICANCE OF THE STUDY: The present study focus on the role and the potential mechanism of DMBT1 in ovarian cancer (OC). We demonstrated that DMBT1 might inhibit the progression of ovarian by inhibiting cell proliferation, migration and invasion and increased the sensitivity to cisplatin through galectin-3/PI3K/AKT pathway. The findings ensure the interaction relation between DMBT1 and galectin-3 in OC, providing a novel biological marker for OC and enriching the potential strategies for OC treatment.

Prognostic role of galectin-3 expression in patients with solid tumors: a meta-analysis of 36 eligible studies

Background

Galectin-3 as a β-galactoside-binding protein, has been found to be involved in tumor cell growth, anti-apoptosis, adhesion, angiogenesis, invasion, and distant metastases, indicating that it may play a pivotal role in cancer development and progression. However, their results remain debatable and inconclusive. Hence, this meta-analysis was performed to clarify the precise predictive value of galectin-3 in various cancers.

Methods

PubMed, Web of Science, Embase, Cochrane Library, CNKI and Wanfang databases were searched comprehensively for eligible studies up to July 15, 2018. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) of OS or DFS/PFS/RFS were calculated to demonstrate their associations.

Results

A total of 36 relevant studies were ultimately enrolled in this meta-analysis. Our results shed light on the significant association of elevated galectin-3 expression with reduced OS or DFS/RFS/PFS in overall cancer patients (pooled HR = 1.79, 95% CI 1.42–2.27, I²= 67.3%, p < 0.01; pooled HR = 1.57, 95% CI 1.04–2.37, I²= 67.1%, p = 0.001). In tumor type subgroup analysis, we found high expression of galectin-3 was correlated with shorter OS or DFS/RFS/PFS in colorectal cancer (pooled HR = 3.05, 95% CI 2.13–4.35, I²= 0.0%, p = 0.734; pooled HR = 2.49, 95% CI 1.82–3.41, I² = 0.0%, p = 0.738; respectively) and meanwhile it merely associated with reduced OS in ovarian cancer or non-small cell lung cancer (pooled HR = 2.24, 95% CI 1.38–3.64, I²= 0.0%, p = 0.910; pooled HR = 2.07, 95% CI 1.48–2.88, I²= 0.0%, p = 0.563; separately).

Conclusions

Taken together, our results suggested that galectin-3 played an oncogenic role in colorectal cancer, ovarian cancer and non-small cell lung cancer, indicating it could be a promising biomarker and a novel therapeutic target for them. Further studies were warranted to validate our findings.

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.

The role of galectin-3 in the tumorigenesis and progression of pituitary tumors

Galectin-3 (Gal-3), a β-galactoside-binding protein, has been implicated in cell proliferation, cell adhesion, and the progression and metastasis of various types of cancer. The present study investigated the involvement of Gal-3 in the tumorigenesis and progression of pituitary tumors using three rat pituitary tumor cell lines. Following transfection with Gal-3 expression and interference vectors, the impact of Gal-3 on proliferation, apoptosis and migration of pituitary tumor cells was been investigated. Meanwhile, BCL2 associated X, apoptosis regulator (Bax), caspase-3 and matrix metalloproteinase 7 (MMP7) protein expression levels were analyzed by western blotting. The results of the present study revealed that Gal-3 expression in GH3 and GH4C1 cells was higher than in RC-4B/C cells. Furthermore, Gal-3 was demonstrated to promote the proliferation and migration of GH3 and GH4C1 cells, and inhibit cell apoptosis. Caspase-3 and MMP7 protein expression was also increased by Gal-3, while Bax expression was decreased. These results suggested that Gal-3 serves an important function in the tumorigenesis and development of pituitary tumors, and it may be a useful target for the treatment of pituitary tumors in the future.

Galectin-3 as a novel biomarker for disease diagnosis and a target for therapy (Review)

Galectin-3 is a member of the galectin family, which are β‑galactoside‑binding lectins with ≥1 evolutionary conserved carbohydrate‑recognition domain. It binds proteins in a carbohydrate‑dependent and ‑independent manner. Galectin‑3 is predominantly located in the cytoplasm; however, it shuttles into the nucleus and is secreted onto the cell surface and into biological fluids including serum and urine. It serves important functions in numerous biological activities including cell growth, apoptosis, pre‑mRNA splicing, differentiation, transformation, angiogenesis, inflammation, fibrosis and host defense. Numerous previous studies have indicated that galectin‑3 may be used as a diagnostic or prognostic biomarker for certain types of heart disease, kidney disease and cancer. With emerging evidence to support the function and application of galectin‑3, the current review aims to summarize the latest literature regarding the biomarker characteristics and potential therapeutic application of galectin‑3 in associated diseases.

Galectin-3 Expression in Colorectal Cancer and its Correlation with Clinical Pathological Characteristics and Prognosis

Objective

To explore the expression levels of galectin-3 in colorectal cancer and the association between galectin-3 and its clinical pathological parameters, as well as the prognosis of colorectal cancer patients.

Methods

An immunohistochemistry assay was used to test the expression levels of galectin-3 in cancer tissues of 61 colorectal cancer cases and in normal intestinal tissues adjacent to the cancer tissues of 23 cases. The associations between protein expression levels of galectin-3 and the clinicopathological features, such as age, sex, pathology type, lymphatic metastasis, and prognosis were also analyzed.

Results

The positive rate of galectin-3 in cancer tissues was significantly higher than that of cancer-adjacent tissues: 62.5% (38/61) versus 13.0% (3/23) (P<0.05), respectively. Correlation was found between the protein expression of galectin-3 and the tumor size (P<0.05), as well as between the tumor differentiation (P<0.05) and Duke staging (P<0.05). The median progression-free survival times of patients with galectin-3 positive and negative expression were 19.2 and 35.1 months, respectively, with significant statistical difference (P<0.05).

Conclusion

Galectin-3 expression was correlated with the genesis and development of colorectal cancer and which could be used a biological marker for the prognosis of colorectal cancer patients.

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.

Reactive oxygen species modulator-1 (Romo1) predicts unfavorable prognosis in colorectal cancer patients

Background

Reactive oxygen species modulator-1 (Romo1) is a novel protein that has been reported to be crucial for cancer cell proliferation and invasion. However, its clinical implications in colorectal cancer patients are not well-known. For the first time, we investigated the association between Romo1 and the clinical outcomes of colorectal cancer patients.

Study

We examined Romo1 expression in resected tumor tissues immunohistochemically and assessed it with histological scores. We conducted survival analyses for patients who had curative resection (n = 190) in accordance with clinical parameters including level of Romo1 expression, and we examined the association between Romo1 expression and cell invasion using Matrigel invasion assay in colorectal cancer cells.

Results

We observed significantly longer mean disease-free survival in the low Romo1 group compared with the high Romo1 group (161 vs 127.6 months, p = 0.035), and the median overall survival of the low Romo1 group was significantly longer than that of the high Romo1 group (196.9 vs 171.3 months, p = 0.036). Cell invasiveness decreased in the Romo1 knockdown colorectal cancer cells in contrast to the controlled cells. Romo1 overexpression in tumor tissue was associated with a high lymph node ratio between the metastatic and examined lymph nodes (p = 0.025).

Conclusions

Romo1 overexpression in tumor tissue was significantly associated with survival in curatively resected colorectal cancer patients, suggesting Romo1 expression as a potential adverse prognostic marker. Increased Romo1 expression was found to be associated with high lymph node ratio. Cancer invasiveness appeared to be a key reason for the poor survival related to highly expressed Romo1.

Clinical significance of galectin-3 in patients with adult acute myeloid leukemia: a retrospective cohort study with long-term follow-up and formulation of risk scoring system

Galectin-3 plays an increasingly important role in development and progression of tumor. However, little is known about the clinical impact of galectin-3 in non-acute promyelocytic leukemia (non-M3 AML). Peripheral blood of 298 patients with primary non-M3 AML and 30 normal donors was collected for measurement of galectin-3. Galectin-3 levels were significantly higher compared with the control group (p < .001). Patients with higher galectin-3 levels had lower CR rates (p = .001) and 1-year overall survival (OS) rates (p = .002). The Kaplan-Meier survival analysis showed that higher galectin-3 levels group had significantly shorter OS. Cox regression model revealed high galectin-3 level was an independent poor prognostic factor. A scoring system incorporating galectin-3 and other prognostic factors (age, WBC, karyotype, NPM1/FLT3-ITD, CEBPA^{double-mutation} and c-KIT, WT1) was formulated to predict prognosis. In conclusion, galectin-3 may be a reliable prognostic marker in AML patients. The multifactorial scoring system was more powerful than a single factor to predict clinical outcome.

Effects of In Utero Exposure to Ethinyl Estradiol on Tamoxifen Resistance and Breast Cancer Recurrence in a Preclinical Model

Background

Responses to endocrine therapies vary among patients with estrogen receptor (ER+) breast cancer. We studied whether in utero exposure to endocrine-disrupting compounds might explain these variations.

Methods

We describe a novel ER+ breast cancer model to study de novo and acquired tamoxifen (TAM) resistance. Pregnant Sprague Dawley rats were exposed to 0 or 0.1 ppm ethinyl estradiol (EE2), and the response of 9,12-dimethylbenz[a]anthracene (DMBA)-induced mammary tumors to 15 mg/kg TAM, with (n = 17 tumors in the controls and n = 20 tumors in EE2 offspring) or without 1.2 g/kg valproic acid and 5 mg/kg hydralazine (n = 24 tumors in the controls and n = 32 tumors in EE2 offspring) in the female offspring, was assessed. One-sided Chi2 tests were used to calculate P values. Comparisons of differentially expressed genes between mammary tumors in in utero EE2-exposed and control rats, and between anti-estrogen-resistant LCC9 and -sensitive LCC1 human breast cancer cells, were also performed.

Results

In our preclinical model, 54.2% of mammary tumors in the control rats exhibited a complete response to TAM, of which 23.1% acquired resistance with continued anti-estrogen treatment and recurred. Mammary tumors in the EE2 offspring were statistically significantly less likely to respond to TAM (P = .047) and recur (P = .007). In the EE2 offspring, but not in controls, adding valproic acid and hydralazine to TAM prevented recurrence (P < .001). Three downregulated and hypermethylated genes (KLF4, LGALS3, MICB) and one upregulated gene (ETV4) were identified in EE2 tumors and LCC9 breast cancer cells, and valproic acid and hydralazine normalized the altered expression of all four genes.

Conclusions

Resistance to TAM may be preprogrammed by in utero exposure to high estrogen levels and mediated through reversible epigenetic alterations in genes associated with epithelial-mesenchymal transition and tumor immune responses.

Impact of Vascular Invasion of a Primary Tumor as a Strong Risk Factor for Disease Recurrence in Patients with Node-Positive Breast Cancer

The presence of lymph node metastasis is considered to be the most significant indicator of prognosis. However, in some cases with node-positive breast cancer, cancer cell dissemination is localized to the lymphatic systems. It is, therefore, important to develop selection criteria for strong adjuvant therapy in patients with node-positive breast cancer. This study was undertaken to evaluate the presence of vascular invasion that may reflect systemic disease as a predictor of disease recurrence in node-positive breast cancer. We retrospectively evaluated the cases of 134 consecutive female patients with breast cancer with lymph node metastasis who underwent radical breast operations. We examined the relationship between recurrence and clinicopathological factors, particularly vascular invasion. The presence of vascular invasion was found to be significant in a univariate analysis. The presence of vascular invasion was the independent risk factor in a multivariate analysis. Among the 66 patients without vascular invasion, four (6.1%) had disease recurrence. On the other hand, among the 68 patients with vascular invasion, 15 (22.1%) had a recurrence. It is interesting to note that despite the presence of lymph node metastasis, the group without vascular invasion had few patients with distant metastases. Our results suggest that the presence of vascular invasion could be an indicator of high biological aggressiveness and may be a strong prognostic factor for node-positive breast cancer.

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.

Extracellular galectin-3 in tumor progression and metastasis

Galectin-3, the only chimera galectin found in vertebrates, is one of the best-studied galectins. It is expressed in several cell types and is involved in a broad range of physiological and pathological processes, such as cell adhesion, cell activation and chemoattraction, cell cycle, apoptosis, and cell growth and differentiation. However, this molecule raises special interest due to its role in regulating cancer cell activities. Galectin-3 has high affinity for β-1,6-N-acetylglucosamine branched glycans, which are formed by the action of the β1,6-N-acetylglucosaminyltransferase V (Mgat5). Mgat5-related changes in protein/lipid glycosylation on cell surface lead to alterations in the clustering of membrane proteins through lattice formation, resulting in functional advantages for tumor cells. Galectin-3 presence enhances migration and/or invasion of many tumors. Galectin-3-dependent clustering of integrins promotes ligand-induced integrin activation, leading to cell motility. Galectin-3 binding to mucin-1 increases transendothelial invasion, decreasing metastasis-free survival in an experimental metastasis model. Galectin-3 also affects endothelial cell behavior by regulating capillary tube formation. This lectin is found in the tumor stroma, suggesting a role for microenvironmental galectin-3 in tumor progression. Galectin-3 also seems to be involved in the recruitment of tumor-associated macrophages, possibly contributing to angiogenesis and tumor growth. This lectin can be a relevant factor in turning bone marrow in a sanctuary for leukemia cells, favoring resistance to therapy. Finally, galectin-3 seems to play a relevant role in orchestrating distinct cell events in tumor microenvironment and for this reason, it can be considered a target in tumor therapies. In conclusion, this review aims to describe the processes of tumor progression and metastasis involving extracellular galectin-3 and its expression and regulation.

Downregulation of galectin-3 causes a decrease in uPAR levels and inhibits the proliferation, migration and invasion of hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is the third most common cause of cancer-related mortality worldwide. Galectin-3 (Gal-3), a multifunctional β-galactoside-binding protein, is highly expressed and associated with the prognosis of HCC. However, the functions of Gal-3 in HCC cells are not fully understood. To address the function of Gal-3 in HCC cells, we used small interfering RNA (siRNA) to knock down Gal-3 expression in HepG2, an HCC cell line. We found that in vitro the silencing of Gal-3 decreased the proliferative activity, colony formation ability, migratory and invasive potential of HepG2 cells. The silencing of Gal-3 significantly decreased the mRNA and protein levels of urokinase-type plasminogen activator receptor (uPAR) as well as uPAR's downstream signaling transduction pathway, including phosphorylation of AKT. Furthermore, the downregulation of Gal-3 by siRNA resulted in significantly decreased activity of the MEK/ERK signaling pathway, and the treatment of HepG2 cells with MEK/ERK inhibitor U0126 significantly reduced the mRNA and protein levels of uPAR. Taken together, our results suggest that Gal-3 modulates uPAR expression via the MEK/ERK pathway, and that Gal-3 may be a potential therapeutic target for the treatment of HCC.

De novo galectin-3 expression influences the response of melanoma cells to isatin-Schiff base copper (II) complex-induced oxidative stimulus

Galectin-3, a ubiquitous member of the galectin family, has been shown to control cellular proliferation, adhesion, migration and apoptosis; thus, it has a role in tumor development and progression. Galectin-3 expression is both up- and down-regulated during melanoma progression. However, conflicting data regarding its roles in tumor biology prompted us to investigate if the presence of galectin-3 influences the response of melanoma cells to a novel metallodrug because metastatic melanoma acquires chemo resistance and is reported to be redox-sensitive. Previously, it was demonstrated that the complex [bis-(2-oxindol-3-yl-imino)-2-(2-aminoethyl) pyridine-N,N'] copper (II) perchlorate, herein referred to as [Cu(isaepy)], induces ROS formation and apoptosis in neuroblastoma cells through mitochondrial uncoupling and the activation of AMPK/p38/p53 signaling. Here, we used a model of vertical growth melanoma (TM1), in which GAL3 expression is lost during tumor progression. When de novo expressed, galectin-3 was found to be ubiquitously present in all subcellular compartments. Our results demonstrate that de novo galectin-3 expression impairs the cellular antioxidant system and renders TM1G3 cells more susceptible than GAL3-null TM1MNG3 cells to [Cu(isaepy)] treatment. This compound, in contrast with the redox inactive [dichloro (2-oxindol-3-yl-imino)-2-(2-aminoethyl) pyridine-N,N'] zinc (II), herein referred to as [Zn(isaepy)], leads to increased intracellular ROS accumulation, increased carbonyl stress, increased mitochondrial depolarization, decreased cell adhesion, increased p38 activation and apoptosis in TM1G3, compared with TM1MNG3. Cell death was shown to be dependent on a hydrogen peroxide-derived species and on the activation of p38. Because mitochondria are a target of both [Cu(isaepy)] and galectin-3, we propose that the presence of galectin-3 in this organelle favors increased ROS production, thereby inducing oxidative cellular damage and apoptotic death. Therefore, [Cu(isaepy)] may be envisaged as a possible anti-melanoma strategy, particularly for melanomas that express galectin-3.