Spatiotemporal regulation of galectin-1-induced T-cell death in lamina propria from Crohn's disease and ulcerative colitis patients

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is characterized by chronic, relapsing intestinal inflammation. Galectin-1 (Gal-1) is an endogenous lectin with key pro-resolving roles, including induction of T-cell apoptosis and secretion of immunosuppressive cytokines. Despite considerable progress, the relevance of Gal-1-induced T-cell death in inflamed tissue from human IBD patients has not been ascertained. Intestinal biopsies and surgical specimens from control patients (n = 52) and patients with active or inactive IBD (n = 97) were studied. Gal-1 expression was studied by RT-qPCR, immunoblotting, ELISA and immunohistochemistry. Gal-1-specific ligands and Gal-1-induced apoptosis of lamina propria (LP) T-cells were determined by TUNEL and flow cytometry. We found a transient expression of asialo core 1-O-glycans in LP T-cells from inflamed areas (p < 0.05) as revealed by flow cytometry using peanut agglutinin (PNA) binding and assessing dysregulation of the core-2 β 1-6-N-acetylglucosaminyltransferase 1 (C2GNT1), an enzyme responsible for elongation of core 2 O-glycans. Consequently, Gal-1 binding was attenuated in CD3⁺CD4⁺ and CD3⁺CD8⁺ LP T-cells isolated from inflamed sites (p < 0.05). Incubation with recombinant Gal-1 induced apoptosis of LP CD3⁺ T-cells isolated from control subjects and non-inflamed areas of IBD patients (p < 0.05), but not from inflamed areas. In conclusion, our findings showed that transient regulation of the O-glycan profile during inflammation modulates Gal-1 binding and LP T-cell survival in IBD patients.

Galectin-1 Contributes to Vascular Remodeling and Blood Flow Recovery After Cerebral Ischemia in Mice

Galectin-1 is found in the vasculature and has been confirmed to promote angiogenesis in several cancer models. Furthermore, galectin-1 has been demonstrated to improve the recovery of cerebral ischemia. However, whether vascular remodeling contributes to this improvement is still unknown. In the present study, photochemical cerebral ischemia was induced in both galectin-1-treated (2 μg/day, i.c.v, 3 days) and galectin-1 knockout mice. Laser speckle imaging and immunofluorescent staining demonstrated that circulation and vascular remodeling in the ischemic cortex were improved by galectin-1 treatment but disrupted in galectin-1 knockout mice. Western blot analysis showed that the expression of matrix metallopeptidase-9 and vascular endothelial growth factor (VEGF) was regulated by galectin-1 in vivo. To determine how galectin-1 influences endothelial cells, the expression of galectin-1 in bEnd.3 cells was increased by transfection with an expression plasmid and knocked down by siRNA. As demonstrated by quantitative RT-PCR and western blot analysis, the expression of metallopeptidase-9, VEGF, and VEGF receptors was upregulated by galectin-1 overexpression but downregulated after galectin-1 knockdown. Flow cytometry, Transwell assay, and capillary-like tube formation assay were performed on cells after gene manipulation as well as cells treated by exogenous galectin-1 after anoxia. It demonstrated that galectin-1 potentiated the cell proliferation, migration capacity, and tube formation ability. Taken together, these data suggest that by targeting vascular remodeling, galectin-1 contributes to the restoration of blood flow, which promotes the recovery of mice after cerebral ischemic insults.

Galectin-1 impacts on glucose homeostasis by modulating pancreatic insulin release

Type-2 diabetes mellitus (T2DM) is an expanding global health problem, involving defective insulin secretion by pancreatic β-cells and peripheral insulin resistance, leading to impaired glucose regulation. Galectin-1, an endogenous lectin with affinity for N-acetyllactosamine (LacNAc)-containing glycans, has emerged as a regulator of inflammatory and metabolic disorders. However, the role of galectin-1 in glucose homeostasis and pancreatic β-cell function, independently of hypercaloric diets, has not been explored. Here, we identified a phenotype compatible with T2DM, involving alterations in glucose metabolism and pancreatic insulin release, in female but not male mice lacking galectin-1 (Lgals1-/-). Compared with age-matched controls, Lgals1-/female mice exhibited higher body weight and increased food intake ad libitum as well as after fasting and acute re-feeding. Although fasted serum insulin levels and insulin sensitivity were similar in both genotypes, Lgals1-/- female mice presented altered glucose tolerance and higher basal glucose levels depending on the fasting period. Insulin response to glucose overload was impaired, while pancreatic insulin content was enhanced in the absence of galectin-1. Accordingly, recombinant galectin-1 enhanced glucose-stimulated insulin release in vitro. Our study identifies a role for galectin-1 in regulating glucose metabolism through modulation of pancreatic insulin secretion, highlighting novel opportunities to control T2DM.

The Role of Galectins in Chronic Lung Allograft Dysfunction

Background

Galectins are proteins that bind β-galactosides such as N-acetyllactosamine present in N-linked and O-linked glycoproteins and that seem to be implicated in inflammatory and immune responses as well as fibrotic mechanisms. This preliminary study investigated serum galectins as clinical biomarkers in lung transplant patients with chronic lung allograft dysfunction (CLAD), phenotype bronchiolitis obliterans syndrome (BOS).

Materials and Methods

Nineteen lung transplant patients [median age (IQR), 55 (45–62) years; 53% males] were enrolled in the study. Peripheral blood concentrations of galectins-1, 3 and 9 were determined with commercial ELISA kits.

Results

Galectin-1 concentrations were higher in BOS than in stable LTX patients (p = 0.0394). In logistic regression analysis, testing BOS group as dependent variable with Gal-1 and 3 as independent variables, area under the receiver operating characteristics (AUROC) curve was 98.9% (NPV 90% and PPV 88.9%, p = 0.0003). With the stable LTX group as dependent variable and Gal-1, 3 and 9 as independent variables, AUROC was 92.6% (NPV 100% and PPV 90%, p = 0.0023). In stable patients were observed an inverse correlation of Gal-3 with DLCO% and KCO%, and between Gal-9 and KCO%.

Conclusion

Galectins-1, 3 and 9 are possible clinical biomarkers in lung transplant patients with diagnostic and prognostic meaning. These molecules may be directly implicated in the pathological mechanisms of BOS. The hypothesis that they could be new therapeutic targets in BOS patients is intriguing and also worth exploring.

Age-related trabecular bone loss is associated with a decline in serum Galectin-1 level

BACKGROUND

Senile osteoporosis with age-related bone loss is diagnosed depending on radiographic changes of bone and bone mineral density (BMD) measurement. However, radiographic alterations are usually signs of medium-late stage osteoporosis. Therefore, biomarkers have been proposed as indicators of bone loss. In the current study, Galectin-1 (Gal-1) showed age-related decline in mice serum. The role of Gal-1 in osteoporosis has not been investigated so far. Hence, the current study illustrated the relationship of serum Gal-1 level with bone loss.

METHODS

We employed 6- and 18-month-old mice to establish an animal model of age-related trabecular bone loss, whose bone density and microstructure were investigated by micro-CT. ELISA was used to measure the levels of Gal-1 in serum. The correlation analysis was performed to illustrate the relationship between serum Gal-1 levels and trabecular bone loss. In addition, immunohistochemistry was used to investigate the abundance of Gal-1 in bone marrow of mice. ELISA and western blot were performed to measure the secretion ability and protein expression of Gal-1 in bone marrow stromal cells (BMSC), hematopoietic stem cells (HSC) and myeloid progenitor (MP) respectively. Flow cytometry was used to measure BMSC number in bone marrow. Finally, male volunteers with age-related BMD decrease were recruited and the relationship between serum Gal-1 and BMD was analyzed.

RESULTS

Gal-1 showed age-related decline in mice serum. Serum Gal-1 was positively associated with BV/TV of femur, tibia and L1 vertebrae in mice. BMSC secreted more Gal-1 compared with HSC and MP. BMSC number in bone marrow was significantly lower in aged mice compared with young mice. Significant attenuation of Gal-1 protein expression was observed in BMSC and HSC from aged mice compared with young mice. Further, we found a decline in serum Gal-1 levels in men with age-related BMD decrease. There was positive correlation between BMD and serum Gal-1 levels in these men.

CONCLUSIONS

Age-related trabecular bone loss is associated with a decline in serum Gal-1 level in mice and men. Our study suggested Gal-1 had great potential to be a biomarker for discovering BMSC senescence, diagnosing early osteoporosis and monitoring trabecular bone loss.

A minigene DNA vaccine encoding peptide epitopes derived from Galectin-1 has protective antitumoral effects in a model of neuroblastoma

We recently identified Galectin-1 (Gal-1), a β-galactoside-binding lectin, as a novel immune regulator in neuroblastoma (NB). Here, we characterized the tolerogenic function of Gal-1 within the CD8⁺ T cell compartment and further evaluated its relevance as an antigen for effective DNA vaccination against NB in a mouse model. NB cells with Gal-1 knockdown (NXS-2L) exhibited significantly reduced tumor growth compared to NXS-2 NB cells. Administration of anti-CD8 antibodies prevented this antitumor effect, with primary tumor growth comparable to that from Gal-1 (G1)-sufficient NB cells. Peptide epitope screening with online databases and in silico docking experiments predicted the sequences "FDQADLTI" (#1), "GDFKIKCV" (#2), and "AHGDANTI" (#3) to have superior H2-KK binding affinities and "KFPNRLNM" (#4), "DGDFKIKCV" (#5), and "LGKDSNNL" (#6) to have superior H2-DD binding affinities. Minigenes encoding G1-KK (#1-#2-#3), G1-DD (#4-#5-#6) and the triplet with the highest affinity, G1-H (#1-#2-#4), were generated and cloned into a ubiquitin-containing plasmid (pU). Mice receiving pU-G1-KK or pU-G-1H presented a reduction in the s.c. tumor volume and weight of up to 80% compared to control mice; this reduction was associated with increased cytotoxicity of isolated splenocytes from vaccinated animals. Vaccination with pUG1-DD showed a lower capability to suppress primary tumor progression. In conclusion, Gal-1 expression by NB negatively regulates CD8⁺ T cells. Vaccination with DNA plasmids encoding Gal-1 epitopes overcomes immune escape, enhances CD8⁺ T cell-dependent immunity and displays effective antitumor activity against NB.

Assessment of Galectin-1, Galectin-3, and PGE2 Levels in Patients with COVID-19

It is important to determine the inflammatory biomarkers in the severity of Coronavirus Disease 2019 (COVID-19) with the emergence of the pandemic. Galectins and prostaglandins play important roles in the regulation of immune and inflammatory responses. Therefore, this study aimed to investigate Galectin-1 (Gal-1), Galectin-3 (Gal-3), and prostaglandin E2 (PGE2) levels in patients with COVID-19. Gal-1, Gal-3, and PGE2 serum concentrations were measured using enzyme-linked immunosorbent analysis (ELISA) on 84 COVID-19 patients (severe=29 and nonsevere=55) and 56 healthy controls. In this study, the increased levels of Gal-1 (median, 9.86, 6.35, 3.67 ng/ml), Gal-3 (median, 415.31, 326.33, 243.13 pg/ml)and PGE2 (median, 193.17, 192.58, 124.62 pg/ml) levels were found in patients with COVID-19 than healthy controls (p<0.001 for all). In the severe group, Gal-3 levels were higher while there were no differences in Gal-1 and PGE2 levels (p=0.011, p=0.263, p=0.921, respectively). There was a positive correlation between serum Gal-1 and Gal-3 levels (ρ=0.871, p<0.001). Gal-3, C-reactive protein, lymphocyte count, and age were found as independent predictors of the disease severity (p=0.002, p=0.001, p=0.007, and p=0.003, respectively). With the emergence of effective drug needs in the COVID-19 pandemic, differentiation of severe disease is important. Gal-3 could be a potential prognostic biomarker of COVID-19.

Human Galectin-1 in Multiple Cancers: A Privileged Molecular Target in Oncology

Galectin-1 (Gal-1), a 14kDa carbohydrate-binding protein of the galectin family found in humans affects intracellular signaling pathways upon interaction with β-galactosides on cell-surface, cytosol, and nucleus. The structural information reveals that it consists of a monovalent dimer composed of subunits with one Carbohydrate Recognition Domain (CRD), which is the main active site to interact with various glycoproteins, and carbohydrates in the body to regulate cellular functions. Gal-1 contributes towards different events associated with cancer biology, including tumor transformation, cell cycle regulation, apoptosis, cell adhesion, migration, and inflammation. The extracellular existence and function of Gal-1 have been well-established, and it is known to express in many tumor types, including astrocytoma, melanoma, prostate, colon, bladder, and ovarian carcinomas, etc. Several studies suggested the upregulation of Gal-1 levels in multiple cancer cells. Thus, Gal-1 is a promising molecular target for the development of new therapeutic tools. The present review focuses on the functions of Gal-1 in tumor progression in multiple cancers and structural insights.

Characterization of a neutralizing anti-human galectin-1 monoclonal antibody with angioregulatory and immunomodulatory activities

Galectins, a family of highly conserved β-galactoside-binding proteins, control tumor progression by modulating different hallmarks of cancer. Galectin-1 (Gal-1), a proto-type member of this family, plays essential roles in tumor angiogenesis and immunosuppression by cross-linking glycosylated receptors on the surface of endothelial and immune cells. Targeted disruption of Gal-1 suppresses tumor growth by counteracting aberrant angiogenesis and reinforcing antitumor immunity in several experimental settings. Given the multiple therapeutic benefits associated with Gal-1 blockade, several Gal-1 inhibitors, including glycan-based competitors, antagonistic peptides, aptamers and neutralizing monoclonal antibodies, have been designed and evaluated in pre-clinical tumor models. Here we report the biochemical and functional characterization of a newly developed neutralizing anti-human Gal-1 monoclonal antibody (Gal-1-mAb3), which specifically recognizes a unique epitope in Gal-1 protein and exerts both angioregulatory and immunomodulatory activities. Blockade of Gal-1 function using Gal-1-mAb3, might be relevant not only in cancer but also in other pathologic conditions characterized by aberrant angiogenesis and uncontrolled immunosuppression.

Proteomic identification of tumor- and metastasis-associated galectin-1 in claudin-low breast cancer

BACKGROUND

Metastasis and mortality remain high among breast cancer patients with the claudin-low subtype because these tumors are aggressive, chemoresistant, and lack targeted therapies. Our objective was to utilize discovery-based proteomics to identify proteins associated with claudin-low primary and metastatic tumors to gain insight into pathways and mechanisms of tumor progression.

METHODS

We used nano-LC-MS/MS proteomics to analyze orthotopic and metastatic tumors from the syngeneic murine T11 tumor model, which displays gene expression profiles mirroring human claudin-low tumors. Galectin-1 identity, expression and spatial distribution were investigated by biochemical and immunochemical methods and MALDI/IMS. RNA seq data from mouse and human tumors in our study and publicly available microarray data were analyzed for differential galectin-1 expression across breast cancer subtypes.

RESULTS

Galectin-1, an N-acetyllactosamine-binding protein, exhibited the highest sequence coverage and high abundance rank order among nano-LC-MS/MS-identified proteins shared by T11 claudin-low tumors but not normal tissue. Label-free quantitation, Western immunoblot and ELISA confirmed galectin-1 identity and significant differential expression. MALDI/IMS spatial mapping and immunohistochemistry detected galectin-1 in T11 metastatic lung foci. Immunohistochemistry of human claudin-low tumors demonstrated intermediate-to-high intensity galectin-1 staining of tumor and stroma. Gene expression analysis of mouse and human tumors found the highest galectin-1 levels in the claudin-low breast cancer subtype.

CONCLUSIONS

Proteomics and genomics reveal high expression of galectin-1 protein and RNA in primary and metastatic claudin-low breast cancer.

GENERAL SIGNIFICANCE

This work endorses proteomic approaches in cancer research and supports further investigations of the function and significance of galectin-1 overexpression in claudin-low tumor progression.

Targeting Galectin-1 by Aflibercept Strongly Enhances Its Antitumor Effect in Neuroendocrine Carcinomas

BACKGROUND

Galectin-1 (Gal-1) plays major roles in cancer by modulating different processes leading to tumor development and progression. In the last years, it has been suggested as a promising target for anticancer therapy. Recently, aflibercept has shown high affinity for Gal-1. Here, we investigated how aflibercept could exert its antitumor activity via Gal-1-driven pathways in neuroendocrine carcinomas (NECs).

METHODS AND RESULTS

NEC tumor xenografts were used to assess the effect of aflibercept on Gal-1 functions. Aflibercept induced a significant reduction of Gal-1 at epithelial, stromal, and extracellular localizations in lung NEC, whereas this was not observed in colon NECs, which displayed low expression of Gal-1. Additionally, aflibercept significantly reduced p-VEGFR2 protein, extracellular matrix remodeling, epithelial-mesenchymal transition, and activation of cancer-associated fibroblast hampering cell invasion in lung NEC but not in colon NEC. Gal-1 screening in human NECs confirmed that pulmonary and pancreatic tumors displayed higher levels of Gal-1 than colon NECs, becoming good candidates to benefit from aflibercept treatment.

CONCLUSIONS

The lack of validated predictive markers of aflibercept is a weakness for guaranteeing the best treatment management with this drug. This work provides new mechanistic insight of aflibercept depending on Gal-1. Thus, in tumors overexpressing Gal-1, aflibercept has not only an antiangiogenic effect but also prevents Gal-1-mediated tumor-stroma cross talk. The stronger aflibercept effect in tumors with high levels of Gal-1 points out this protein as a molecular marker to predict the efficacy of this agent not only for NECs but also for other tumors with high levels of this protein.

Effects of galectin-1 on immunomodulatory properties of human monocyte-derived dendritic cells

Our study aimed to evaluate the effects of Gal-1 in dose depending manner on maturation and immunomodulatory properties of monocyte-derived (Mo) DCs in-vitro. The effects were analyzed by monitoring their phenotypic characteristics, cytokine profile, and the ability to direct the immune response in the co-culture with allogeneic CD4⁺T cells. Gal-1 reduced the expression of CD80 and CD86 molecules on MoDCs compared to untreated MoDCs. Gal-1 at concentrations of 1 and 6 μg/mL significantly reduced IL-12 production, while the concentration of 3 μg/mL led to its significant increase. Gal-1 in all concentrations induced a significant increase in the production of IL-10. Treatment of MoDCs with 3 and 6 μg/mL of Gal-1 stimulated the production of IL-2 and IFN-γ in the co-culture with CD4⁺T lymphocytes. This study demonstrated a dual immunomodulatory effect of Gal-1 on MoDCs in terms of immune stimulation and immune suppression, depending on the applied concentration.

Galectin-1 promotes vasculogenic mimicry in gastric adenocarcinoma via the Hedgehog/GLI signaling pathway

Background: Galectin-1 (GAL-1), which is encoded by LGALS1, promotes vasculogenic mimicry (VM) in gastric cancer (GC) tissue. However, the underlying mechanism remains unclear.

Methods: Immunohistochemical (IHC) and CD34-periodic acid-Schiff (PAS) double staining were used to investigate Glioma-associated oncogene-1(GLI1) expression and VM in paraffin-embedded sections from 127 patients with GC of all tumor stages. LGALS1 or GLI1 were stably transduced into MGC-803 cells and AGS cells, and western blotting, IHC, CD34-PAS double staining and three-dimensional culture in vitro, and tumorigenicity in vivo were used to explore the mechanisms of GAL-1/ GLI1 promotion of VM formation in GC tissues.

Results: A significant association between GAL-1 and GLI1 expression was identified by IHC staining, as well as a significant association between GLI1 expression and VM formation. Furthermore, overexpression of LGALS1 enhanced expression of GLI1 in MGC-803 and AGS cells. GLI1 promoted VM formation both in vitro and in vivo. The effects of GLI1 on VM formation were independent of LGALS1. Importantly, the expression of VM-related molecules, such as MMP2, MMP14 and laminin5γ2, was also affected upon GLI1 overexpression or silencing in GC cell lines. Conclusion: GAL-1 promotes VM in GC through the Hh/GLI pathway, which has potential as a novel therapeutic target for treatment of VM in GC.

TF-containing MUC1 glycopeptides fail to entice Galectin-1 recognition of tumor-associated Thomsen-Freidenreich (TF) antigen (CD176) in solution

Aberrant Mucin-1 (MUC1) glycosylation with the Thomsen-Friedenreich (TF) tumor-associated antigen (CD176) is a hallmark of epithelial carcinoma progression and poor patient prognosis. Recognition of TF by glycan-binding proteins, such as galectins, enables the pathological repercussions of this glycan presentation, yet the underlying binding specificities of different members of the galectin family is a matter of continual investigation. While Galectin-3 (Gal-3) recognition of TF has been well-documented at both the cellular and molecular level, Galectin-1 (Gal-1) recognition of TF has only truly been alluded to in cell-based platforms. Immunohistochemical analyses have purported Gal-1 binding to TF on MUC1 at the cell surface, however binding at the molecular level was inconclusive. We hypothesize that glycan scaffold (MUC1's tandem repeat peptide sequence) and/or multivalency play a role in the binding recognition of TF antigen by Gal-1. In this study we have developed a method for large-scale expression of Gal-1 and its histidine-tagged analog for use in binding studies by isothermal titration calorimetry (ITC) and development of an analytical method based on AlphaScreen technology to screen for Gal-1 inhibitors. Surprisingly, neither glycan scaffold or multivalent presentation of TF antigen on the scaffold was able to entice Gal-1 recognition to the level of affinity expected for functional significance. Future evaluations of the Gal-1/TF binding interaction in order to draw connections between immunohistochemical data and analytical measurements are warranted.

LncRNA MEG3-210 regulates endometrial stromal cells migration, invasion and apoptosis through p38 MAPK and PKA/SERCA2 signalling via interaction with Galectin-1 in endometriosis

BACKGROUND

Endometriosis is a benign gynaecological disease with malignant characteristics that severely affects women's quality of life. Long noncoding RNA maternally expressed gene 3 (LncRNA MEG3) is a tumour suppressor that is downregulated in various cancer cells and tissues, and regulates multiple biological processes. Emerging studies have revealed that the interactions between MEG3 and proteins are involved in disease progression. Galectin-1 affects cell motility, signal transduction and vascularization, and is overexpressed in endometriosis. Our study is the first to explore the role of MEG3-210 transcript in endometriosis and to reveal the regulatory mechanism mediated by the interaction between MEG3-210 and Galectin-1.

MATERIALS AND METHODS

Endometrial tissues and sera from patients with endometriosis and controls were collected. qRT-PCR was performed to detect the expression of MEG3-210 in the endometrium and endometrial stromal cells (ESCs). The CCK-8 assay, the Transwell assay, flow cytometry and animal models were conducted to evaluate the functions of MEG3-210 in vitro and in vivo. Bioinformatic analysis, Western blot assays, RNA-pull down assays and RNA immunoprecipitation were used to explore the potential mechanism of MEG3-210 in endometriosis.

RESULTS

Our results showed that MEG3-210 expression was lower in the eutopic endometrium of women with endometriosis. MEG3-210 downregulation promoted ESCs migration, invasion, anti-apoptosis in vitro and growth of endometriotic lesions in vivo. Furthermore, MEG3-210 downregulation could activate p38 mitogen-activated protein kinase (p38 MAPK) and inhibit cAMP-dependent protein kinase A/sarcoplasmic reticulum Ca²⁺ ATPase 2 (PKA/SERCA2) signalling, which was mediated by Galectin-1. The protein levels of Galectin-1 in patients with endometriosis were elevated, and Galectin-1 siRNA could reduce the size of lesions.

CONCLUSION

MEG3-210 regulates ESCs through p38 MAPK and PKA/SERCA signalling via interaction with Galectin-1. The novel regulatory mechanism may provide new insights into drug therapy and the diagnosis of endometriosis.

Novel benzimidazole-triazole hybrids as apoptosis inducing agents in lung cancer: Design, synthesis, 18F-radiolabeling & galectin-1 inhibition studies

In this study, we have synthesized a new series of benzimidazole-triazole hybrids as galectin-1 (gal-1) mediated apoptosis-inducing agents, and evaluated for their potential anticancer activity against a panel of human cancer cell lines viz. breast cancer (MCF-7 and MDA-MB-231) lung cancer (A-549 and NCI-H460), and human keratinocyte cancer (HaCaT), using MTT assay. The target compound 7c exhibited an excellent growth inhibition against lung cancer (A-549 and NCI-H460) cells with an IC₅₀ value of 0.63 ± 0.21 µM, and 0.99 ± 0.01 µM respectively. The target compound 7c also showed a significant growth inhibition against breast cancer (MCF-7 and MDA-MB-23) with an IC₅₀ value of 1.3 ± 0.18 µM, and 0.94 ± 0.02 µM respectively. In addition, the radiochemical synthesis has been performed using fluorine-18 radionuclide in the GE Tracer-lab FX2N module to prove the target compound 7c as a PET imaging agent. In the final stage, the ¹⁸F-7c target compound was successfully purified with 60% ethanol in water. The radiochemical purity was achieved >95% using HPLC, and the residual solvent DMF limit was around 78 ± 3 ppm confirmed by GC analysis. Further, the apoptosis induction by 7c in lung cancer (A-549) cells was confirmed as a result of the decrease in MMP levels, increased percentage of apoptotic cells, and sub G1 phase arrest by JC-1 staining, DAPI staining, annexin V-FITC/PI, and flow cytometric analysis. In addition, the target compound 7c significantly reduced the gal-1 protein levels in a dose-dependent manner as confirmed by ELISA studies. The protein binding studies like Surface Plasmon Resonance (SPR) and Fluorescence Spectroscopy (FS) studies indicated that the target compound 7c is capable of binding to gal-1 with an equilibrium constant (K_D) value of 1.19E-06 M, and binding constant (K_a) of 9.5 × 10³ M^-1 respectively. The in-silico computational studies also revealed possible interactions and pharmacokinetic properties (ADMET) of compound 7c with the binding domain of gal-1. Therefore, the novel benzimidazole-triazole hybrids as apoptosis-inducing agents in lung cancer would be potential cytotoxic and PET imaging agents via gal-1.

BRAF inhibition curtails IFN-gamma-inducible PD-L1 expression and upregulates the immunoregulatory protein galectin-1 in melanoma cells

Although melanoma is considered one of the most immunogenic malignancies, spontaneous T‐cell responses to melanoma antigens are ineffective due to tumor cell‐intrinsic or microenvironment‐driven immune evasion mechanisms. For example, oncogenic BRAF V600E mutation in melanoma cells fosters tumor immune escape by modulating cell immunogenicity and microenvironment composition. BRAF inhibition has been shown to increase melanoma cell immunogenicity, but these effects are transient and long‐term responses are uncommon. For these reasons, we aimed to further characterize the role of BRAF‐V600E mutation in the modulation of PD‐L1, a known immunoregulatory molecule, and galectin‐1 (Gal‐1), a potent immunoregulatory lectin involved in melanoma immune privilege. We report herein that vemurafenib downregulates IFN‐γ‐induced PD‐L1 expression by interfering with STAT1 activity and by decreasing PD‐L1 protein translation. Surprisingly, melanoma cells exposed to vemurafenib expressed higher levels of Gal‐1. In coculture experiments, A375 melanoma cells pretreated with vemurafenib induced apoptosis of interacting Jurkat T cells, whereas genetic inhibition of Gal‐1 in these cells restored the viability of cocultured T lymphocytes, indicating that Gal‐1 contributes to tumor immune escape. Importantly, Gal‐1 plasma concentration increased in patients progressing on BRAF/MEK inhibitor treatment, but remained stable in responding patients. Taken together, these results suggest a two‐faceted nature of BRAF inhibition‐associated immunomodulatory effects: an early immunostimulatory activity, mediated at least in part by decreased PD‐L1 expression, and a delayed immunosuppressive effect associated with Gal‐1 induction. Importantly, our observations suggest that Gal‐1 might be utilized as a potential biomarker and a putative therapeutic target in melanoma patients.

Galectin-1 expression in oral squamous cell carcinoma: An immunohistochemical study

Context:

Oral squamous cell carcinoma (OSCC) of the head and neck are a heterogeneous group of neoplasms with an increasing rate of mortality and morbidity. OSCCs are characterized by a high degree of local invasiveness and metastasis to cervical lymph nodes but show a lower rate of distant metastasis. Galectin-1 (Gal-1), a β-galactoside-binding lectin, is known to regulate tumor cell growth, angiogenesis, mediate cell-cell or cell-extracellular matrix adhesion and promote cancer cell migration.

Aims:

This study aims to evaluate the Gal-1 expression in different clinical stages and histological grades of OSCC.

Settings and Design:

Forty histopathologically diagnosed cases of OSCC, including 16 cases of well-differentiated, 18 moderately differentiated and 6 poorly differentiated carcinomas, were included in the study group.

Materials and Methods:

The samples were subjected to staining using primary mouse monoclonal antibodies against Gal-1 and visualized using polymer-HRP detection system.

Statistical Analysis:

The nonparametric Mann–Whitney U-test and Kruskal–Wallis ANOVA test were used for the statistical analysis.

Results:

Gal-1 expression was higher in advanced stages of OSCC, and the results were statistically significant. Immunoexpression of Gal-1 increased with advancing histological grades of OSCC with statistically significant results.

Conclusion:

Gal-1 plays an important role in invasion, metastasis and as a prognostic marker.

Angiostrongylus cantonensis Galectin-1 interacts with Annexin A2 to impair the viability of macrophages via activating JNK pathway

BACKGROUND

Angiostrongylus cantonensis can cause severe symptoms of central nervous system infections. In the host, this parasite localizes in the blood and cerebrospinal fluid, and its secreted components can impact immune responses. Our previous study demonstrated that immune responses were inhibited in A. cantonensis-infected mice immunized with Ac-Galectin-1 (AcGal-1). However, the mechanisms by which AcGal-1 regulates the immune responses remain unclear. Macrophages are innate immune cells that rapidly respond to infection. The direct impact of AcGal-1 on macrophages may affect the immune responses.

METHODS

AcGal-1 protein was purified by nickel ion affinity chromatography. The effect of AcGal-1 on the apoptosis of macrophages was detected using CCK-8 assay, flow cytometry and western blot. Macrophage membrane proteins bound to AcGal-1 were obtained using the His-tag-based pull-down assay and identified via mass spectrometry. Co-localization of AcGal-1 and the macrophage membrane protein Annexin A2 was observed by immunofluorescence microscopy, and their interaction was validated by co-immunoprecipitation experiments. SiRNA-mediated knockdown of Annexin A2 was used to determine if AcGal-1-induced macrophage apoptosis required interaction with Annexin A2. The phosphorylation level of apoptotic signal pathway protein was detected by phospho-antibody microarray and western blot.

RESULTS

Our study showed that AcGal-1 caused apoptosis of the macrophages. AcGal-1 increased the expression of apoptosis proteins caspase-3, caspase-9, Bax, but reduced the expression of anti-apoptosis protein Bcl-2. AcGal-1 interacted with the membrane protein Annexin A2, and knockdown of Annexin A2 expression increased Bcl-2 but decreased Bax levels in AcGal-1-treated cells. Moreover, AcGal-1 increased JNK phosphorylation and the inhibition of JNK phosphorylation in AcGal-1-treated cells decreased the expression of caspase-3, -9, Bax and almost restored Bcl-2 to the level observed in control cells.

CONCLUSIONS

AcGal-1 can induce the apoptosis of macrophages by binding to Annexin A2 and activating JNK downstream the apoptotic signaling pathway.

Galectin-1-Related Modulation of Trophoblast Endothelial Interactions by Integrins α1 and β1

During normal trophoblast invasion, integrins α6β4 are downregulated, and α1β1 are upregulated in invasive cytotrophoblast cells. In preeclampsia both interstitial and endovascular invasion are shallow and cytotrophoblasts fail to upregulate α1β1 and downregulate α6β4. This study aims to investigate the role of integrins α1β1 and α6β4 on cellular pathways influencing trophoblast integration into endothelial cellular networks in vitro. Red fluorescent-labeled human uterine myometrial microvascular endothelial cells (UtMVECs) were seeded on Matrigel to form endothelial networks. Green fluorescent-labeled trophoblastic HTR-8/SVneo cells pre-incubated with 20 μg/ml of neutralizing antibodies (anti-α1, β1, α6, β4, α1 + β1, or α6 + β4) for 1 h were then co-cultured with endothelial networks with the neutralizing antibodies for 24 h. Fluorescent images were captured, and quantified utilizing Image J. Cells were retrieved to analyze mRNA expression of galectin-1, TIMP-1, and PAI-1 by quantitative PCR. MMP-2, MMP-9, free sFlt-1, and PlGF from conditioned media were measured by ELISA. The integration of trophoblast cells into endothelial cellular networks was inhibited by anti-β1(- 28 ± 3%, p < 0.0001), and increased by anti-α6(+ 19 ± 5%, p < 0.01). Galectin-1 mRNA expression was decreased by anti-α1(- 35 ± 7%, p < 0.001), anti-β1(- 23 ± 5%, p < 0.05), and anti-α1+β1(- 35 ± 5%, p < 0.001). The mRNA expression of TIMP-1 was inhibited by anti-α1(- 59 ± 9%, p < 0.01) and anti-β1(- 63 ± 7%, p < 0.001) while PAI-1 mRNA expression was increased by anti-α1 + β1(+ 285 ± 70%, p < 0.0001). In the conditioned medium, anti-α1 reduced MMP-2(-28 ± 1%, p < 0.001), MMP-9(-27 ± 8%, p < 0.01), and sFlt-1(-27 ± 5%, p < 0.001) production. Anti-β1 reduced MMP-2(- 15 ± 2%, p < 0.05) production. There were no changes in PlGF. Appropriate integrins α1β1 modulate trophoblast cell integration into endothelial cellular networks in vitro through invasive pathways including galectin-1, TIMP-1, PAI-1, MMP-2, and MMP-9 production.

Impaired emotional response to stress in mice lacking galectin-1 or galectin-3

Galectin-1 (Gal-1) and galectin-3 (Gal-3) are multifunctional glycan-binding proteins, expressed in the brain and in its limbic structures that are involved in behavioral control. Gal-1 induces the expression of the brain-derived neurotrophic factor (BDNF) and promotes adult neural stem cells proliferation, biological events impaired in stress-related psychiatric disorders, such as depression and anxiety. Despite that, there is no evidence regarding galectin involvement in emotional control during stressful situations. Thus, we analyzed the behavioral phenotype of Gal-1 or Gal-3 knock-out mice (Gal-1 KO or Gal-3 KO) in different experimental models predictive of depressive and compulsive-like behaviors.

METHODS

C57BL-6 Gal-1 KO, Gal-3 KO, and wild-type mice (WT) were analyzed under the open field test (OFT) and, 6 h later, under the forced swim test (FST). Additionally, independent groups of male mice, lacking galectins or not, were exposed to the tail suspension test (TST) or to the marble burying test (MBT). The hippocampus and prefrontal cortex (PFC) of the mice submitted to MBT were dissected to access BDNF levels.

RESULTS

Both Gal-1 and Gal-3 KO mice showed increased time of immobility in the FST and in the TST compared to WT animals, thus reflecting an impaired stress-coping behavior. Additionally, Gal-1 and Gal-3 KO female mice presented increased compulsive-like behavior in the MBT, without significant changes in the locomotor activity. BDNF levels were found to be decreased in the PFC of Gal-1 KO mice.

DISCUSSION

Our results demonstrate that the absence of either endogenous Gal-1 and Gal-3 impairs stress-coping and increases compulsive-like behavior, suggesting that Gal-1 and Gal-3 are involved in the neurobiology of depression and obsessive-compulsive-like disorder.

Effects of Galectin-1 on Biological Behavior in Cervical Cancer

Background: We previously revealed that the expression of galectin-1 (LGALS1) was significantly reduced after neoadjuvant chemotherapy treatment in cervical cancer patients. The objective of this study is to investigate the effects of LGALS1 expression on biological behaviors of cervical cancer cells.

Methods: Immunohistochemistry and immunocytochemistry were performed to detect the expression of LGALS1 in cervical cancer tissues and cells (SiHa and C33A). Western blot analysis was performed to evaluate the efficacy of lentivirus-mediated upregulation or downregulation of LGALS1 in cervical cancer cells. Cell viability and proliferation were detected by CCK-8 and BrdU assays, respectively. Annexin V-FITC/PI apoptosis detection kit was employed to measure the apoptosis of cervical cancer cells. Transwell invasion and migration assays were also conducted to explore the invasive and migratory capabilities of cervical cancer cells. The expression of apoptosis- (Bcl-2 and Bax), invasion- (MMP-2 and MMP-9), and migration-related (Fascin and Ezrin) proteins, were detected by Western blot analysis. Xenograft mouse model of cervical cancer was generated to explore whether LGALS1 overexpression could promote tumor growth in vivo.

Results: LGALS1 was overexpressed in cervical cancer tissues and cell lines compared to that in normal cervical tissues and epithelium cells. Upregulation of LGALS1 significantly promoted the cell proliferation, inhibited cell apoptosis, and enhanced the migratory and invasive abilities of both SiHa and C33A cells, whereas downregulation of LGALS1 led to the opposite results. The level of Bcl-2, MMP-2, MMP-9, Fascin, and Erzin expression was significantly upregulated in cervical cancer cells with LGALS1 overexpression, while converse results were obtained in LGALS1 knockdown cancer cells. In vivo study also showed that LGALS1 overexpression facilitated tumor growth of cervical cancer cells.

Conclusion: Overexpression of LGALS1 significantly promoted and enhanced the aggressive features of cervical cancer both in vitro and in vivo, which may be associated with high expression of Bcl-2, MMP-2, MMP-9, Fascin, and Erzin proteins.

Galectin-1 attenuates neurodegeneration in Parkinson's disease model by modulating microglial MAPK/IκB/NFκB axis through its carbohydrate-recognition domain

The vicious cycle between the chronicactivationofmicroglia and dopamine neurons degeneration is linked with the progression of Parkinson's disease (PD). Targeting microglialactivationhas proven to be a viable option to develop a disease-modified therapy for PD. Galectin-1, which has been reported to have an anti-neuroinflammation effect was used in the present study to evaluate its therapeutic effects on microglia activation and neuronal degeneration in Parkinson's disease model. It was found that galectin-1 attenuated the inflammatory insult and the apoptosis of SK-N-SH human neuroblastoma cells from conditioned medium of activated microglia induced by Lipopolysaccharides (LPS). Nonetheless, galectin-1 administration (0.5 mg/kg) inhibited the microglia activation, improved the motor deficits in PD mice model induced by MPTP (25 mg/kg weight of mouse, i.p.) and prevented the degeneration of dopaminergic neurons in the substantia nigra. Administration of galectin-1 resulted in p38 and ERK1/2 dephosphorylation followed by IκB/NFκB signaling pathway inhibition. Galectin-1 significantly decreased the secretion of pro-inflammatory cytokines, including interleukin (IL)-1β, tumor necrosis factor-α (TNF-α), and protein levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). The protective effects and modulation of the MAPK/IκB/NFκB signaling pathway were abolished with β-D-galactose which blocked the carbohydrate-recognition domain of galectin-1. The present study demonstrated that galectin-1 inhibited microglia activation and ameliorated neurodegenerative process in PD model by modulating MAPK/IκB/NFκB axis through its carbohydrate-recognition domain.

Shikonin induces colorectal carcinoma cells apoptosis and autophagy by targeting galectin-1/JNK signaling axis

Colorectal carcinoma (CRC) is the third most common malignant tumor pathology worldwide. Despite progress in surgical procedures and therapy options, CRC is still a considerable cause of cancer-related mortality. In this study, we tested the antitumor effects of shikonin in CRC and tried to identify its potential mechanism. The potential target, molecular mechanism as well as in vitro and in vivo antitumor effects of shikonin in CRC cells were determined by an integrative protocol including quantitative proteomics, RT-PCR, western blotting, RNA interference and overexpression, apoptosis and autophagy assays, etc. Galectin-1 was a potential target of shikonin from the iTRAQ-based proteomic analysis in shikonin-treated SW620 cell. The overexpression and RNA silencing of galectin-1 in two CRC cells suggested that the shikonin sensitivity was correlation to galectin-1 levels. The ROS accumulation induced by shikonin was important to the formation of galectin-1 dimers. Dimer galectin-1 was found to be associated with the activation of JNK and downstream apoptosis or autophagy. Moreover, through functional in vitro studies, we showed that differences in galectin-1 level affected tumor cell proliferation, migration, and invasion. In summary, shikonin induced CRC cells apoptosis and autophagy by targeting galectin-1 and JNK signaling pathway both in vitro and in vivo, which suggested a potential novel therapy target for CRC.

Galectin-1 ameliorates lipopolysaccharide-induced acute lung injury via AMPK-Nrf2 pathway in mice

Inflammation and oxidative stress contribute to the progression of acute lung injury (ALI). Galectin-1 (Gal-1) has important anti-inflammatory properties in renal ischemia-reperfusion injury, arthritis, uveitis, and hepatitis. However, whether Gal-1 could protect against ALI is still poorly elucidated. The current study aimed to investigate the protective effects of Gal-1 against lipopolysaccharide (LPS)-induced ALI and the underlying mechanisms. Accordingly, we found that pretreatment with Gal-1 attenuated the lung tissue injury induced by LPS, with the recovery of lung function, protecting against the production of pro-inflammatory cytokines and oxidative stress. We also confirmed the therapeutic potential of Gal-1 on the survival rate of LPS-challenged mice. In vitro studies demonstrated the protective effects of exogenous Gal-1 through downregulating pro-inflammatory cytokines release and oxidative stress in primary macrophages challenged by LPS. In addition, Gal-1 suppressed TXNIP-NLRP3 inflammasome activation in ALI mice and LPS-treated primary macrophages partly through directly binding to the NLRP3 protein. Gal-1 alleviated LPS-induced lung injury via activation of Nrf-2, which may be associated with AMPK phosphorylation. Collectively, our experimental results firstly provided the support that Gal-1 effectively protected against LPS-induced ALI via suppression of inflammation response and oxidative stress, which were largely dependent on the upregulation of the Nrf2 pathway via phosphorylation of AMPK. These results suggest that Gal-1 could be a valuable therapeutic candidate in the treatment of ALI.