Human umbilical cord mesenchymal stem cell-derived exosomes carrying hsa-miRNA-128-3p suppress pancreatic ductal cell carcinoma by inhibiting Galectin-3

BackgroundPancreatic ductal adenocarcinoma (PDAC) is one of the most fatal malignant tumors of the digestive system. Many patients are diagnosed at an advanced stage and lose eligibility for surgery. Moreover, there are few effective methods for treating pancreatic ductal cell carcinoma. Increasing attention has been given to microRNAs (miRNAs) and their regulatory roles in tumor progression. In this study, we investigated the effects of exosomes extracted from human umbilical cord mesenchymal stem cells (HUCMSCs) carrying hsa-miRNA-128-3p on pancreatic cancer cells.MethodsBased on existing experimental and database information, we selected Galectin-3, which is associated with pancreatic cancer, and the corresponding upstream hsa-miRNA-128-3p. We extracted HUCMSCs from a fresh umbilical cord, hsa-miRNA-128-3p was transfected into HUCMSCs, and exosomes containing hsa-miRNA-128-3p were extracted and collected. The effect of exosomes rich in hsa-miRNA-128-3p on pancreatic cancer cells was analyzed.ResultsThe expression of Galectin-3 in normal pancreatic duct epithelial cells was significantly lower than that in PDAC cell lines. We successfully extracted HUCMSCs from the umbilical cord and transfected hsa-miRNA-128-3p into HUCMSCs. Then we demonstrated that HUCMSC-derived exosomes with hsa-miRNA-128-3p could suppress the proliferation, invasion, and migration of PANC-1 cells in vitro by targeting Galectin-3.ConclusionHsa-miRNA-128-3p could be considered as a potential therapy for pancreatic cancer. We provided a new idea for targeted therapy of PDAC.

Gal3 Plays a Deleterious Role in a Mouse Model of Endotoxemia.

Lipopolysaccharide (LPS)-induced endotoxemia induces an acute systemic inflammatory response that mimics some important features of sepsis, the disease with the highest mortality rate worldwide. In this work, we have analyzed a murine model of endotoxemia based on a single intraperitoneal injection of 5 mg/kg of LPS. We took advantage of galectin-3 (Gal3) knockout mice and found that the absence of Gal3 decreased the mortality rate oflethal endotoxemia in the first 80 h after the administration of LPS, along with a reduction in the tissular damage in several organs measured by electron microscopy. Using flow cytometry, we demonstrated that, in control conditions, peripheral immune cells, especially monocytes, exhibited high levels of Gal3, which were early depleted in response to LPS injection, thus suggesting Gal3 release under endotoxemia conditions. However, serum levels of Gal3 early decreased in response to LPS challenge (1 h), an indication that Gal3 may be extravasated to peripheral organs. Indeed, analysis of Gal3 in peripheral organs revealed a robust up-regulation of Gal3 36 h after LPS injection. Taken together, these results demonstrate the important role that Gal3 could play in the development of systemic inflammation, a well-established feature of sepsis, thus opening new and promising therapeutic options for these harmful conditions.

Human umbilical cord mesenchymal stem cell-derived exosomes carrying hsa-miRNA-128-3p suppress pancreatic ductal cell carcinoma by inhibiting Galectin-3.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is one of the most fatal malignant tumors of the digestive system. Many patients are diagnosed at an advanced stage and lose eligibility for surgery. Moreover, there are few effective methods for treating pancreatic ductal cell carcinoma. Increasing attention has been given to microRNAs (miRNAs) and their regulatory roles in tumor progression. In this study, we investigated the effects of exosomes extracted from human umbilical cord mesenchymal stem cells (HUCMSCs) carrying hsa-miRNA-128-3p on pancreatic cancer cells. METHODS: Based on existing experimental and database information, we selected Galectin-3, which is associated with pancreatic cancer, and the corresponding upstream hsa-miRNA-128-3p. We extracted HUCMSCs from a fresh umbilical cord, hsa-miRNA-128-3p was transfected into HUCMSCs, and exosomes containing hsa-miRNA-128-3p were extracted and collected. The effect of exosomes rich in hsa-miRNA-128-3p on pancreatic cancer cells was analyzed. RESULTS: The expression of Galectin-3 in normal pancreatic duct epithelial cells was significantly lower than that in PDAC cell lines. We successfully extracted HUCMSCs from the umbilical cord and transfected hsa-miRNA-128-3p into HUCMSCs. Then we demonstrated that HUCMSC-derived exosomes with hsa-miRNA-128-3p could suppress the proliferation, invasion, and migration of PANC-1 cells in vitro by targeting Galectin-3. CONCLUSION: Hsa-miRNA-128-3p could be considered as a potential therapy for pancreatic cancer. We provided a new idea for targeted therapy of PDAC.

Targeted disruption of galectin 3 in mice delays the first wave of spermatogenesis and increases germ cell apoptosis.

Galectin 3 is a multifunctional lectin implicated in cellular proliferation, differentiation, adhesion, and apoptosis. This lectin is broadly expressed in testicular somatic cells and germ cells, and is upregulated during testicular development. Since the role of galectin 3 in testicular function remains elusive, we aimed to characterize the role of galectin 3 in testicular physiology. We found that galectin 3 transgenic mice (Lgals3-/-) exhibited significantly decreased testicular weight in adulthood compared to controls. The transgenic mice also exhibited a delay to the first wave of spermatogenesis, a decrease in the number of germ cells at postnatal day 5 (P5) and P15, and defective Sertoli cell maturation. Mechanistically, we found that Insulin-like-3 (a Leydig cell marker) and enzymes involved in steroid biosynthesis were significantly upregulated in adult Lgals3-/- testes. These observations were accompanied by increased serum testosterone levels. To determine the underlying causes of the testicular atrophy, we monitored cellular apoptosis. Indeed, adult Lgals3-/- testicular cells exhibited an elevated apoptosis rate that is likely driven by downregulated Bcl-2 and upregulated Bax and Bak expression, molecules responsible for live/death cell balance. Moreover, the percentage of testicular macrophages within CD45+ cells was decreased in Lgals3-/- mice. These data suggest that galectin 3 regulates spermatogenesis initiation and Sertoli cell maturation in part, by preventing germ cells from undergoing apoptosis and regulating testosterone biosynthesis. Going forward, understanding the role of galectin 3 in testicular physiology will add important insights into the factors governing the development of germ cells and steroidogenesis and delineate novel biomarkers of testicular function.

Galectin-3 gene deletion results in defective adipose tissue maturation and impaired insulin sensitivity and glucose homeostasis.

Adiposopathy is a pathological adipose tissue (AT) response to overfeeding characterized by reduced AT expandability due to impaired adipogenesis, which favors inflammation, insulin resistance (IR), and abnormal glucose regulation. However, it is unclear whether defective adipogenesis causes metabolic derangement also independently of an increased demand for fat storage. As galectin-3 has been implicated in both adipocyte differentiation and glucose homeostasis, we tested this hypothesis in galectin-3 knockout (Lgal3-/-) mice fed a standard chow. In vitro, Lgal3-/- adipocyte precursors showed impaired terminal differentiation (maturation). Two-month-old Lgal3-/- mice showed impaired AT maturation, with reduced adipocyte size and expression of adipogenic genes, but unchanged fat mass and no sign of adipocyte degeneration/death or ectopic fat accumulation. AT immaturity was associated with AT and whole-body inflammation and IR, glucose intolerance, and hyperglycemia. Five-month-old Lgal3-/- mice exhibited a more mature AT phenotype, with no difference in insulin sensitivity and expression of inflammatory cytokines versus WT animals, though abnormal glucose homeostasis persisted and was associated with reduced ß-cell function. These data show that adipogenesis capacity per se affects AT function, insulin sensitivity, and glucose homeostasis independently of increased fat intake, accumulation and redistribution, thus uncovering a direct link between defective adipogenesis, IR and susceptibility to diabetes.

Mapping glycan-mediated galectin-3 interactions by live cell proximity labeling.

Galectin-3 is a glycan-binding protein (GBP) that binds ß-galactoside glycan structures to orchestrate a variety of important biological events, including the activation of hepatic stellate cells and regulation of immune responses. While the requisite glycan epitopes needed to bind galectin-3 have long been elucidated, the cellular glycoproteins that bear these glycan signatures remain unknown. Given the importance of the three-dimensional (3D) arrangement of glycans in dictating GBP interactions, strategies that allow the identification of GBP receptors in live cells, where the native glycan presentation and glycoprotein expression are preserved, have significant advantages over static and artificial systems. Here we describe the integration of a proximity labeling method and quantitative mass spectrometry to map the glycan and glycoprotein interactors for galectin-3 in live human hepatic stellate cells and peripheral blood mononuclear cells. Understanding the identity of the glycoproteins and defining the structures of the glycans will empower efforts to design and develop selective therapeutics to mitigate galectin-3-mediated biological events.

Galectin-3 favours tumour metastasis via the activation of ß-catenin signalling in hepatocellular carcinoma.

BACKGROUND: High probability of metastasis limited the long-term survival of patients with hepatocellular carcinoma (HCC). Our previous study revealed that Galectin-3 was closely associated with poor prognosis in HCC patients. METHODS: The effects of Galectin-3 on tumour metastasis were investigated in vitro and in vivo, and the underlying biological and molecular mechanisms involved in this process were evaluated. RESULTS: Galectin-3 showed a close correlation with vascular invasion and poor survival in a large-scale study in HCC patients from multiple sets. Galectin-3 was significantly involved in diverse metastasis-related processes in HCC cells, such as angiogenesis and epithelial-to-mesenchymal transition (EMT). Mechanistically, Galectin-3 activated the PI3K-Akt-GSK-3ß-ß-catenin signalling cascade; the ß-catenin/TCF4 transcriptional complex directly targeted IGFBP3 and vimentin to regulate angiogenesis and EMT, respectively. In animal models, Galectin-3 enhanced the tumorigenesis and metastasis of HCC cells via ß-catenin signalling. Moreover, molecular deletion of Galectin-3-ß-catenin signalling synergistically improved the antitumour effect of sorafenib. CONCLUSIONS: The Galectin-3-ß-catenin-IGFBP3/vimentin signalling cascade was determined as a central mechanism controlling HCC metastasis, providing possible biomarkers for predicating vascular metastasis and sorafenib resistance, as well as potential therapeutic targets for the treatment of HCC patients.

Mac-2-binding protein glycan isomer enhances the aggressiveness of hepatocellular carcinoma by activating mTOR signaling.

BACKGROUND: Wisteria floribunda agglutinin (WFA)+ Mac-2-binding protein (M2BPGi) is a novel serum marker for liver fibrosis. Although an elevated serum level of M2BPGi can predict development of hepatocellular carcinoma (HCC), the effect of M2BPGi on HCC remains unclear. There are no reports about the association of M2BPGi with HCC aggressiveness. We aimed to clarify the significance of M2BPGi in HCC. METHODS: The protein expression of M2BPGi and galectin-3, a ligand of M2BP, and the mRNA expression of M2BP were evaluated in surgically resected human HCC samples. M2BPGi-regulating signals in HCC cells were investigated using transcriptome analysis. The effects of M2BPGi on HCC properties and galectin-3/mTOR signaling were evaluated. RESULTS: M2BPGi and galectin-3 proteins co-localised in HCC cells, while M2BP mRNA was detected in cirrhotic liver stromal cells. mTOR signaling was upregulated in M2BPGi-treated HCC cells. Moreover, M2BPGi treatment induced tumour-promoting effects on HCC in vitro by activated mTOR signaling. In addition, M2BPGi bound to galectin-3 to induce membranous galectin-3 expression in HCC cells. In vivo, M2BPGi enhanced the growth of xenografted HCC. CONCLUSIONS: M2BPGi is produced in stromal cells of the cirrhotic liver. Furthermore, M2BPGi enhances the progression of HCC through the galectin-3/mTOR pathway.

Galectin-3 mediates survival and apoptosis pathways during Trypanosoma cruzi-host cell interplay.

Neglected tropical diseases, such as Chagas disease caused by the protozoa Trypanosoma cruzi, affect millions of people worldwide but lack effective treatments that are accessible to the entire population, especially patients with the debilitating chronic phase. The recognition of host cells, invasion and its intracellular replicative success are essential stages for progression of the parasite life cycle and the development of Chagas disease. It is predicted that programmed cell death pathways (apoptosis) would be activated in infected cells, either via autocrine secretion or mediated by cytotoxic immune cells. This process should play a key role in resolving infections by hindering the evolutionary success of the parasite. In this research, we performed assays to investigate the role of the lectin galectin-3 (Gal3) in parasite-host signaling pathways. Using cells with endogenous levels of Gal3 compared to Gal3-deficient cells (induced by RNA interference), we demonstrated that T. cruzi mediated the survival pathways and the subverted apoptosis through Gal3 promoting a pro-survival state in infected cells. Infected Gal3-depleted cells showed increased activation of caspase 3 and pro-apoptotic targets, such as poly (ADP-ribose) polymerase (PARP), and lower accumulation of anti-apoptotic proteins, such as c-IAP1, survivin and XIAP. During the early stages of infection, Gal3 translocates from the cytoplasm to the nucleus and must act in survival pathways. In a murine model of experimental infection, Gal3 knockout macrophages showed lower infectivity and viability. In vivo infection revealed a lower parasitemia and longer survival and an increased spleen cellularity in Gal3 knockout mice with consequences on the percentage of T lymphocytes (CD4+ CD11b+) and macrophages. In addition, cytokines such as IL-2, IL-4, IL-6 and TNF-α are increased in Gal3 knockout mice when compared to wild type genotype. These data demonstrate a Gal3-mediated complex interplay in the host cell, keeping infected cells alive long enough for infection and intracellular proliferation of new parasites. However, a continuous knowledge of these signaling pathways should contribute to a better understanding the mechanisms of cell death subversion that are promoted by protozoans in the pathophysiology of neglected diseases such as Chagas disease.

Galectin-3 Identifies a Subset of Macrophages With a Potential Beneficial Role in Atherosclerosis.

OBJECTIVE: Galectin-3 (formerly known as Mac-2), encoded by the LGALS3 gene, is proposed to regulate macrophage adhesion, chemotaxis, and apoptosis. We investigated the role of galectin-3 in determining the inflammatory profile of macrophages and composition of atherosclerotic plaques. Approach and Results: We observed increased accumulation of galectin-3-negative macrophages within advanced human, rabbit, and mouse plaques compared with early lesions. Interestingly, statin treatment reduced galectin-3-negative macrophage accrual in advanced plaques within hypercholesterolemic (apolipoprotein E deficient) Apoe-/- mice. Accordingly, compared with Lgals3+/+:Apoe-/- mice, Lgals3-/-:Apoe-/- mice displayed altered plaque composition through increased macrophage:smooth muscle cell ratio, reduced collagen content, and increased necrotic core area, characteristics of advanced plaques in humans. Additionally, macrophages from Lgals3-/- mice exhibited increased invasive capacity in vitro and in vivo. Furthermore, loss of galectin-3 in vitro and in vivo was associated with increased expression of proinflammatory genes including MMP (matrix metalloproteinase)-12, CCL2 (chemokine [C-C motif] ligand 2), PTGS2 (prostaglandin-endoperoxide synthase 2), and IL (interleukin)-6, alongside reduced TGF (transforming growth factor)-ß1 expression and consequent SMAD signaling. Moreover, we found that MMP12 cleaves macrophage cell-surface galectin-3 resulting in the appearance of a 22-kDa fragment, whereas plasma levels of galectin-3 were reduced in Mmp12-/-:Apoe-/- mice, highlighting a novel mechanism where MMP12-dependent cleavage of galectin-3 promotes proinflammatory macrophage polarization. Moreover, galectin-3-positive macrophages were more abundant within plaques of Mmp12-/-:Apoe-/- mice compared with Mmp12+/+:Apoe-/- animals. CONCLUSIONS: This study reveals a prominent protective role for galectin-3 in regulating macrophage polarization and invasive capacity and, therefore, delaying plaque progression.

Galectin-3 promotes Aß oligomerization and Aß toxicity in a mouse model of Alzheimer's disease.

Amyloid-ß (Aß) oligomers largely initiate the cascade underlying the pathology of Alzheimer's disease (AD). Galectin-3 (Gal-3), which is a member of the galectin protein family, promotes inflammatory responses and enhances the homotypic aggregation of cancer cells. Here, we examined the role and action mechanism of Gal-3 in Aß oligomerization and Aß toxicities. Wild-type (WT) and Gal-3-knockout (KO) mice, APP/PS1;WT mice, APP/PS1;Gal-3+/- mice and brain tissues from normal subjects and AD patients were used. We found that Aß oligomerization is reduced in Gal-3 KO mice injected with Aß, whereas overexpression of Gal-3 enhances Aß oligomerization in the hippocampi of Aß-injected mice. Gal-3 expression shows an age-dependent increase that parallels endogenous Aß oligomerization in APP/PS1 mice. Moreover, Aß oligomerization, Iba1 expression, GFAP expression and amyloid plaque accumulation are reduced in APP/PS1;Gal-3+/- mice compared with APP/PS1;WT mice. APP/PS1;Gal-3+/- mice also show better acquisition and retention performance compared to APP/PS1;WT mice. In studying the mechanism underlying Gal-3-promoted Aß oligomerization, we found that Gal-3 primarily co-localizes with Iba1, and that microglia-secreted Gal-3 directly interacts with Aß. Gal-3 also interacts with triggering receptor expressed on myeloid cells-2, which then mediates the ability of Gal-3 to activate microglia for further Gal-3 expression. Immunohistochemical analyses show that the distribution of Gal-3 overlaps with that of endogenous Aß in APP/PS1 mice and partially overlaps with that of amyloid plaque. Moreover, the expression of the Aß-degrading enzyme, neprilysin, is increased in Gal-3 KO mice and this is associated with enhanced integrin-mediated signaling. Consistently, Gal-3 expression is also increased in the frontal lobe of AD patients, in parallel with Aß oligomerization. Because Gal-3 expression is dramatically increased as early as 3 months of age in APP/PS1 mice and anti-Aß oligomerization is believed to protect against Aß toxicity, Gal-3 could be considered a novel therapeutic target in efforts to combat AD.

The Role of Galectin-3 in Subarachnoid Hemorrhage: A Preliminary Study.

Despite advances in diagnosis and treatment of subarachnoid hemorrhage (SAH), combined morbidity and mortality rate in SAH patients accounted for greater than 50%. Many prognostic factors have been reported including delayed cerebral ischemia, cerebral vasospasm-induced infarction, and shunt-dependent hydrocephalus as potentially preventable or treatable causes. Recent experimental studies emphasize that early brain injury, a concept to explain acute pathophysiological events that occur in brain before onset of cerebral vasospasm within the first 72 h of SAH, may be more important than cerebral vasospasm, a classically important determinant of poor outcome, in post-SAH outcome. Galectin-3 is known for one of matricellular proteins and a mediator of inflammation in the central nervous system. Galectin-3 was also reported to contribute to poor outcomes in SAH patients, but the role of galectin-3 after SAH has not been determined. We produced experimental SAH mice, of which the top of the internal carotid artery was perforated by 4-0 monofilament, and evaluated effects of a galectin-3 inhibitor. We assessed neurological scores and brain water content at 24 h. The administration of a galectin-3 inhibitor significantly ameliorated brain edema and neuronal score in experimental SAH mice.

Galectin-3 Regulates Indoleamine-2,3-dioxygenase-Dependent Cross-Talk between Colon-Infiltrating Dendritic Cells and T Regulatory Cells and May Represent a Valuable Biomarker for Monitoring the Progression of Ulcerative Colitis.

Galectin-3 regulates numerous biological processes in the gut. We investigated molecular mechanisms responsible for the Galectin-3-dependent regulation of colon inflammation and evaluated whether Galectin-3 may be used as biomarker for monitoring the progression of ulcerative colitis (UC). The differences in disease progression between dextran sodium sulphate-treated wild type and Galectin-3-deficient mice were investigated and confirmed in clinical settings, in 65 patients suffering from mild, moderate, and severe colitis. During the induction phase of colitis, Galectin-3 promoted interleukin-1ß-induced polarization of colonic macrophages towards inflammatory phenotype. In the recovery phase of colitis, Galectin-3 was required for the immunosuppressive function of regulatory dendritic cells (DCs). Regulatory DCs in Galectin-3:Toll-like receptor-4:Kynurenine-dependent manner promoted the expansion of colon-infiltrated T regulatory cells (Tregs) and suppressed Th1 and Th17 cell-driven colon inflammation. Concentration of Galectin-3 in serum and stool samples of UC patients negatively correlated with clinical, endoscopic, and histological parameters of colitis. The cutoff serum values of Galectin-3 that allowed the discrimination of mild from moderate and moderate from severe colitis were 954 pg/mL and 580 pg/mL, respectively. Fecal levels of Galectin-3 higher than 553.44 pg/mL indicated attenuation of UC. In summing up, Galectin-3 regulates the cross-talk between colon-infiltrating DCs and Tregs and represents a new biomarker for monitoring the progression of UC.

Galectin-3, a novel endogenous TREM2 ligand, detrimentally regulates inflammatory response in Alzheimer's disease.

Alzheimer's disease (AD) is a progressive neurodegenerative disease in which the formation of extracellular aggregates of amyloid beta (Aß) peptide, fibrillary tangles of intraneuronal tau and microglial activation are major pathological hallmarks. One of the key molecules involved in microglial activation is galectin-3 (gal3), and we demonstrate here for the first time a key role of gal3 in AD pathology. Gal3 was highly upregulated in the brains of AD patients and 5xFAD (familial Alzheimer's disease) mice and found specifically expressed in microglia associated with Aß plaques. Single-nucleotide polymorphisms in the LGALS3 gene, which encodes gal3, were associated with an increased risk of AD. Gal3 deletion in 5xFAD mice attenuated microglia-associated immune responses, particularly those associated with TLR and TREM2/DAP12 signaling. In vitro data revealed that gal3 was required to fully activate microglia in response to fibrillar Aß. Gal3 deletion decreased the Aß burden in 5xFAD mice and improved cognitive behavior. Interestingly, a single intrahippocampal injection of gal3 along with Aß monomers in WT mice was sufficient to induce the formation of long-lasting (2 months) insoluble Aß aggregates, which were absent when gal3 was lacking. High-resolution microscopy (stochastic optical reconstruction microscopy) demonstrated close colocalization of gal3 and TREM2 in microglial processes, and a direct interaction was shown by a fluorescence anisotropy assay involving the gal3 carbohydrate recognition domain. Furthermore, gal3 was shown to stimulate TREM2-DAP12 signaling in a reporter cell line. Overall, our data support the view that gal3 inhibition may be a potential pharmacological approach to counteract AD.

An Orally Active Galectin-3 Antagonist Inhibits Lung Adenocarcinoma Growth and Augments Response to PD-L1 Blockade.

A combination therapy approach is required to improve tumor immune infiltration and patient response to immune checkpoint inhibitors that target negative regulatory receptors. Galectin-3 is a ß-galactoside-binding lectin that is highly expressed within the tumor microenvironment of aggressive cancers and whose expression correlates with poor survival particularly in patients with non-small cell lung cancer (NSCLC). To examine the role of galectin-3 inhibition in NSCLC, we tested the effects of galectin-3 depletion using genetic and pharmacologic approaches on syngeneic mouse lung adenocarcinoma and human lung adenocarcinoma xenografts. Galectin-3-/- mice developed significantly smaller and fewer tumors and metastases than syngeneic C57/Bl6 wild-type mice. Macrophage ablation retarded tumor growth, whereas reconstitution with galectin-3-positive bone marrow restored tumor growth in galectin-3-/- mice, indicating that macrophages were a major driver of the antitumor response. Oral administration of a novel small molecule galectin-3 inhibitor GB1107 reduced human and mouse lung adenocarcinoma growth and blocked metastasis in the syngeneic model. Treatment with GB1107 increased tumor M1 macrophage polarization and CD8+ T-cell infiltration. Moreover, GB1107 potentiated the effects of a PD-L1 immune checkpoint inhibitor to increase expression of cytotoxic (IFNγ, granzyme B, perforin-1, Fas ligand) and apoptotic (cleaved caspase-3) effector molecules. In summary, galectin-3 is an important regulator of lung adenocarcinoma progression. The novel galectin-3 inhibitor presented could provide an effective, nontoxic monotherapy or be used in combination with immune checkpoint inhibitors to boost immune infiltration and responses in lung adenocarcinoma and potentially other aggressive cancers. SIGNIFICANCE: A novel and orally active galectin-3 antagonist inhibits lung adenocarcinoma growth and metastasis and augments response to PD-L1 blockade.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/79/7/1480/F1.large.jpg.

Galectin-3 Inhibits Cancer Metastasis by Negatively Regulating Integrin ß3 Expression.

Galectin-3 (Gal-3; gene LGALS3) is a member of the ß-galactose-binding lectin family. Previous studies showed that Gal-3 is expressed in several tissues across species and functions as a regulator of cell proliferation, apoptosis, adhesion, and migration, thus affecting many aspects of events, such as angiogenesis and tumorigenesis. Although several reports have suggested that the level of Gal-3 expression correlates positively with tumor progression, herein we show that highly metastatic mouse melanoma B16/BL6 cells express less Gal-3 than B16 cells with a lower metastatic potential. It was found that overexpression of Gal-3 in melanoma cells in fact suppresses metastasis. In contrast, knocking out Gal-3 expression in cancer cells promoted cell aggregation mediated through interactions with platelets and fibrinogen in vitro and increased the number of metastatic foci in vivo. Thus, reduced Gal-3 expression results in the up-regulation of ß3 integrin expression, and this contributes to metastatic potential. These findings indicate that changes of Gal-3 expression in cancer cells during tumor progression influence the characteristics of metastatic cells.

RAGE/galectin-3 yields intraplaque calcification transformation via sortilin.

AIMS: Macrocalcification and microcalcification present different clinical risks, but the regulatory of their formation was unclear. Therefore, this study explored the underlying mechanisms of macrocalcification and microcalcification in diabetes mellitus. METHODS: Anterior tibial arteries of amputated diabetic feet were collected. According to the calcium content, patients were divided into less-calcification group and more-calcification group. And calcification morphology in plaques was observed. For further study, an in vivo mouse diabetic atherosclerosis model and an in vitro primary mouse aortic smooth muscle cell model were established. After the receptors for AGEs (RAGE) or galectin-3 were silenced, calcified nodule sizes and sortilin expression were determined. Scanning electron microscopy (SEM) was performed to detect the aggregation of matrix vesicles with the inhibition or promotion of sortilin. RESULTS: Both macro- and microcalcification were found in human anterior tibial artery plaques. Macrocalcification formed after the silencing of RAGE, and microcalcification formed after the silencing of galectin-3. In the process of RAGE- or galcetin-3-induced calcification, sortilin played an important role downstream. SEM showed that sortilin promoted the aggregation of MVs in the early stage of calcification and formed larger calcified nodules. CONCLUSION: RAGE downregulated sortilin and then transmitted microcalcification signals, whereas galectin-3 upregulated sortilin, which accelerated the aggregation of MVs in the early stage of calcification and mediated the formation of macrocalcifications, These data illustrate the progression of two calcification types and suggest sortilin as a potential target for early intervention of calcification and as an effective biomarker for the assessment of long-term clinical risk and prognosis.

The Ocular Surface Glycocalyx and its Alteration in Dry Eye Disease: A Review.

Many studies have revealed that transmembrane mucins, large glycoproteins with heavily glycosylated glycans, are essential for maintaining ocular surface epithelium lubrication and wettability. Recent reports indicate that transmembrane mucins and galectin-3, a chimera type of galectin that binds ß-galactoside in the glycan, play a crucial role in maintaining the epithelial glycocalyx barrier. This review summarizes current evidence regarding the role of galectin-3, the role of the three major transmembrane mucins (i.e., MUC1, MUC4, and MUC16), in the maintenance of ocular surface wettability and transcellular barrier. Pathological mechanisms of glycocalyx barrier disruption and epithelial surface wettability decreases in dry eye disease are also summarized. Lastly, new ophthalmic drugs that target transmembrane mucin are described.

Left ventricular remodeling after the first myocardial infarction in association with LGALS-3 neighbouring variants rs2274273 and rs17128183 and its relative mRNA expression: a prospective study.

Post-infarct left ventricular remodeling (LVR) process increases the risk of heart failure (HF). Circulating galectin-3 has been associated with fibrosis, inflammation and cardiac dysfunction during the remodeling process after myocardial infarction (MI). The aims of this prospective case study were to investigate the association of potentially functional variants in the vicinity of LGALS-3 locus, rs2274273 and rs17128183 with maladaptive LVR and whether these variants could affect LGALS-3 mRNA expression in peripheral blood mononuclear cells of patients 6 months after the first MI. This study encompassed 167 patients with acute MI that were followed up for 6 months. Evidence of LVR was obtained by repeated 2D Doppler echocardiography. Rs2274273, rs17128183 and LGALS-3 mRNA expression were detected by TaqMan® technology. Rs2274273 and rs17128183 rare allele bearing genotypes, according to the dominant model (CT+TT vs. CC and AG+GG vs. AA, respectively), were significantly and independently associated with maladaptive LVR (adjusted OR = 3.02, P = 0.016; adjusted OR = 3.14, P = 0.019, respectively) and higher LGALS-3 mRNA expression (fold induction 1.203, P = 0.03 and 1.214, P = 0.03, respectively). Our exploratory results suggest that rs2274273 and rs17128183 variants affect LGALS-3 mRNA and bear the risk for maladaptive LVR post-MI remodeling. Further replication and validation in a larger group of patients is inevitable.

[Role and mechanism of Galectin-3 gene in proliferation, invasion, and apoptosis of oral squamous cell carcinoma].

OBJECTIVE: The effect and mechanism of Galectin-3 gene expression on proliferation, invasion, and apoptosis of oral squamous cell carcinoma (OSCC) were investigated. METHODS: Reverse transcription-polymerase chain reaction (RT-
PCR) and Western blotting were used to detect the mRNA and protein of Galectin-3 gene in OSCC. OSCC Tca8113 was divided into control, negative control, and Galectin-3 transfection groups. Western blotting was used to detect the expression of Galectin-3, matrix metalloproteinase (MMP)-2, MMP-9, Cleaved Caspase-3, ß-catenin, and Cyclin D1 protein after transfection for 48 h in each group. Cell proliferation was detected by CCK8. Cell invasion ability was detected by using a Transwell chamber. Cell apoptosis was detected by flow cytometry. RESULTS: The mRNA and protein expression levels of Galectin-3 gene in OSCC were significantly higher than those in adjacent tissues (P<0.01). Galectin-3 protein expression in Tca8113 cells significantly decreased after RNA interference. Cell survival rate and invasion as well as MMP-2, MMP-9, ß-catenin, and Cyclin D1 protein expression were significantly lower than the blank group. Apoptosis rate and Cleaved Caspase-3 protein expression were significantly higher than the control group (P<0.01). CONCLUSIONS: Inhibition of Galectin-3 gene expression in OSCC can significantly reduce the proliferation and invasion of cancer cells and induce apoptosis. The mechanism is related to downregulation of the Wnt/ß-catenin signaling pathway.