Galectin-1 as a potent target for cancer therapy: role in the tumor microenvironment

Glycomimetic inhibitors of tandem-repeat galectins: Simple and efficient

The binding of human galectins by glycomimetic inhibitors is a promising therapeutic approach. The structurally distinct group of tandem-repeat galectins has scarcely been studied so far, and there is hardly any knowledge on their ligand specificity or their inhibitory potential, particularly concerning non-natural carbohydrates. Here, we present the synthesis of a library of seven 3-O-disubstituted thiodigalactoside-derived glycomimetics and their affinity to two tandem-repeat galectins, Gal-8 and Gal-9. The straightforward synthesis of these glycomimetics involved dibutyltin oxide-catalyzed 3,3́-O-disubstitution of commercially available unprotected thiodigalactoside, and conjugation of various aryl substituents by copper-catalyzed Huisgen azide-alkyne cycloaddition (CuAAC). The inhibitory potential of the prepared glycomimetics for Gal-8 and Gal-9 was assessed, and compared with the established galectins Gal-1 and Gal-3. The introduction of C-3 substituents resulted in an over 40-fold increase in affinity compared with unmodified TDG. The structure-affinity relations within the studied series were discussed using molecular modeling. Furthermore, the prepared glycomimetics were shown to scavenge Gal-8 and Gal-9 from the surface of cancer cells. This pioneering study on the synthetic inhibitors especially of Gal-9 identified lead compounds that may be used in further biomedical research.

Fibroblasts Derived From Vestibular Schwannoma Express Protumorogenic Markers

BACKGROUND AND AIM

Vestibular schwannomas (VSs), despite being histologically benign, cause significant morbidity because of their challenging intracranial location and the propensity for growth. The role of the stroma and particularly fibroblasts, in the progression of VS, is not completely understood. This study examines the profile of fibroblasts in VS.

METHODS

Seventeen patients undergoing surgical excision of VS were recruited into the study. Reverse transcription with quantitative polymerase chain reaction (RT-qPCR) was performed on VS tissue samples and fibroblast-associated molecules examined. Immunofluorescence and immunohistochemistry in VS tissue were used to study the expression of fibroblast markers CD90 and podoplanin in situ. Fibroblast cultures were established from VS, and RT-qPCR analysis was performed on a panel of fibroblast markers on VS and control tissue fibroblasts.

RESULTS

Several fibroblast-associated molecules including members of galectin family and matrix metalloproteinases were found to be expressed in VS tissue on RT-qPCR analysis. In situ, expression of CD90 and podoplanin was observed in VS tissue both on immunohistochemistry and immunofluorescence. RT-qPCR analysis of fibroblasts from VS and control vestibular neuroepithelium (NE) showed a higher expression of several molecules of the galectin and matrix metalloproteinases family on VS fibroblasts compared with NE fibroblasts.

CONCLUSION

This work examines fibroblasts from VS and shows qualitative differences from NE fibroblasts on RT-qPCR. Further understanding of the fibroblast function in the progression of VS will potentially unveil new targets to manage VS growth.

Galectin-1 in Pancreatic Ductal Adenocarcinoma: Bridging Tumor Biology, Immune Evasion, and Therapeutic Opportunities

Pancreatic Ductal Adenocarcinoma (PDAC) remains one of the most challenging malignancies to treat, with a complex interplay of molecular pathways contributing to its aggressive nature. Galectin-1 (Gal-1), a member of the galectin family, has emerged as a pivotal player in the PDAC microenvironment, influencing various aspects from tumor growth and angiogenesis to immune modulation. This review provides a comprehensive overview of the multifaceted role of Galectin-1 in PDAC. We delve into its contributions to tumor stroma remodeling, angiogenesis, metabolic reprogramming, and potential implications for therapeutic interventions. The challenges associated with targeting Gal-1 are discussed, given its pleiotropic functions and complexities in different cellular conditions. Additionally, the promising prospects of Gal-1 inhibition, including the utilization of nanotechnology and theranostics, are highlighted. By integrating recent findings and shedding light on the intricacies of Gal-1's involvement in PDAC, this review aims to provide insights that could guide future research and therapeutic strategies.

Conjugating 4β-NH-(5-Aminoindazole)-podophyllotoxin and Galectin-1-Targeted Aptamer for Synergistic Chemo-Immunotherapy of Hepatocellular Carcinoma

By conjugating a chemotherapeutic candidate drug 4β-NH-(5-aminoindazole)-podophyllotoxin (βIZP) and an immunosuppressive protein galectin-1 targeted aptamer AP74, a chemo-immunotherapy molecule (AP74-βIZP) is developed against liver cancer. AP74-βIZP can target galectin-1 and enrich the tumor microenvironment to improve the tumor inhibition ratio by 6.3%, higher than that of βIZP in a HepG2 xenograft model. In safety evaluation, βIZP cannot be released from AP74-βIZP in normal tissues with low glutathione level. Therefore, the degrees of organs injury and myelosuppression after the treatment with AP74-βIZP are lower than those with βIZP. After 21 d treatment at a drug dose of 5 mg kg-1 , AP74-βIZP does not cause weight loss in mice, while the weight is significantly reduced by 24% and 14% from oxaliplatin and βIZP, respectively. In immune synergy, AP74-IZP enhances CD4/CD8 cell infiltration to promote the expression of cell factor (i.e., IL-2, TNF-α, and IFN-γ), which further improves the antitumor activity. The tumor inhibition ratio of AP74-βIZP is 70.2%, which is higher than that of AP74 (35.2%) and βIZP (48.8%). Because of the dual effects of chemotherapy and immunotherapy, AP74-βIZP exhibits superior activity and lower toxicity. The approach developed in this work could be applicable to other chemotherapy drugs.

Galectin-1: A Traditionally Immunosuppressive Protein Displays Context-Dependent Capacities

Galectin–Carbohydrate interactions are indispensable to pathogen recognition and immune response. Galectin-1, a ubiquitously expressed 14-kDa protein with an evolutionarily conserved β-galactoside binding site, translates glycoconjugate recognition into function. That galectin-1 is demonstrated to induce T cell apoptosis has led to substantial attention to the immunosuppressive properties of this protein, such as inducing naive immune cells to suppressive phenotypes, promoting recruitment of immunosuppressing cells as well as impairing functions of cytotoxic leukocytes. However, only in recent years have studies shown that galectin-1 appears to perform a pro-inflammatory role in certain diseases. In this review, we describe the anti-inflammatory function of galectin-1 and its possible mechanisms and summarize the existing therapies and preclinical efficacy relating to these agents. In the meantime, we also discuss the potential causal factors by which galectin-1 promotes the progression of inflammation.

Biological impact and therapeutic perspective of targeting PI3K/Akt signaling in hepatocellular carcinoma: Promises and Challenges

Cancer progression results from activation of various signaling networks. Among these, PI3K/Akt signaling contributes to proliferation, invasion, and inhibition of apoptosis. Hepatocellular carcinoma (HCC) is a primary liver cancer with high incidence rate, especially in regions with high prevalence of viral hepatitis infection. Autoimmune disorders, diabetes mellitus, obesity, alcohol consumption, and inflammation can also lead to initiation and development of HCC. The treatment of HCC depends on the identification of oncogenic factors that lead tumor cells to develop resistance to therapy. The present review article focuses on the role of PI3K/Akt signaling in HCC progression. Activation of PI3K/Akt signaling promotes glucose uptake, favors glycolysis and increases tumor cell proliferation. It inhibits both apoptosis and autophagy while promoting HCC cell survival. PI3K/Akt stimulates epithelial-to-mesenchymal transition (EMT) and increases matrix-metalloproteinase (MMP) expression during HCC metastasis. In addition to increasing colony formation capacity and facilitating the spread of tumor cells, PI3K/Akt signaling stimulates angiogenesis. Therefore, silencing PI3K/Akt signaling prevents aggressive HCC cell behavior. Activation of PI3K/Akt signaling can confer drug resistance, particularly to sorafenib, and decreases the radio-sensitivity of HCC cells. Anti-cancer agents, like phytochemicals and small molecules can suppress PI3K/Akt signaling by limiting HCC progression. Being upregulated in tumor tissues and clinical samples, PI3K/Akt can also be used as a biomarker to predict patients' response to therapy.

Galectin-1 and Galectin-3 in B-Cell Precursor Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemias arising from the malignant transformation of B-cell precursors (BCP-ALLs) are protected against chemotherapy by both intrinsic factors as well as by interactions with bone marrow stromal cells. Galectin-1 and Galectin-3 are lectins with overlapping specificity for binding polyLacNAc glycans. Both are expressed by bone marrow stromal cells and by hematopoietic cells but show different patterns of expression, with Galectin-3 dynamically regulated by extrinsic factors such as chemotherapy. In a comparison of Galectin-1 x Galectin-3 double null mutant to wild-type murine BCP-ALL cells, we found reduced migration, inhibition of proliferation, and increased sensitivity to drug treatment in the double knockout cells. Plant-derived carbohydrates GM-CT-01 and GR-MD-02 were used to inhibit extracellular Galectin-1/-3 binding to BCP-ALL cells in co-culture with stromal cells. Treatment with these compounds attenuated migration of the BCP-ALL cells to stromal cells and sensitized human BCP-ALL cells to vincristine and the targeted tyrosine kinase inhibitor nilotinib. Because N-glycan sialylation catalyzed by the enzyme ST6Gal1 can regulate Galectin cell-surface binding, we also compared the ability of BCP-ALL wild-type and ST6Gal1 knockdown cells to resist vincristine treatment when they were co-cultured with Galectin-1 or Galectin-3 knockout stromal cells. Consistent with previous results, stromal Galectin-3 was important for maintaining BCP-ALL fitness during chemotherapy exposure. In contrast, stromal Galectin-1 did not significantly contribute to drug resistance, and there was no clear effect of ST6Gal1-catalysed N-glycan sialylation. Taken together, our results indicate a complicated joint contribution of Galectin-1 and Galectin-3 to BCP-ALL survival, with different roles for endogenous and stromal produced Galectins. These data indicate it will be important to efficiently block both extracellular and intracellular Galectin-1 and Galectin-3 with the goal of reducing BCP-ALL persistence in the protective bone marrow niche during chemotherapy.

Galectins Are Central Mediators of Immune Escape in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers and is highly immune tolerant. Although there is immune cell infiltration in PDAC tissues, most of the immune cells do not function properly and, therefore, the prognosis of PDAC is very poor. Galectins are carbohydrate-binding proteins that are intimately involved in the proliferation and metastasis of tumor cells and, in particular, play a crucial role in the immune evasion of tumor cells. Galectins induce abnormal functions and reduce numbers of tumor-associated macrophages (TAM), natural killer cells (NK), T cells and B cells. It further promotes fibrosis of tissues surrounding PDAC, enhances local cellular metabolism, and ultimately constructs tumor immune privileged areas to induce immune evasion behavior of tumor cells. Here, we summarize the respective mechanisms of action played by different Galectins in the process of immune escape from PDAC, focusing on the mechanism of action of Galectin-1. Galectins cause imbalance between tumor immunity and anti-tumor immunity by coordinating the function and number of immune cells, which leads to the development and progression of PDAC.

Immunoregulatory signal networks and tumor immune evasion mechanisms: insights into therapeutic targets and agents in clinical development

Through activation of immune cells, the immune system is responsible for identifying and destroying infected or otherwise damaged cells including tumorigenic cells that can be recognized as foreign, thus maintaining homeostasis. However, tumor cells have evolved several mechanisms to avoid immune cell detection and killing, resulting in tumor growth and progression. In the tumor microenvironment, tumor infiltrating immune cells are inactivated by soluble factors or tumor promoting conditions and lose their effects on tumor cells. Analysis of signaling and crosstalk between immune cells and tumor cells have helped us to understand in more detail the mechanisms of tumor immune evasion and this forms basis for drug development strategies in the area of cancer immunotherapy. In this review, we will summarize the dominant signaling networks involved in immune escape and describe the status of development of therapeutic strategies to target tumor immune evasion mechanisms with focus on how the tumor microenvironment interacts with T cells.

Cancer Stem Cells in Tumor Microenvironment of Adenocarcinoma of the Stomach, Colon, and Rectum

Simple Summary

Gastrointestinal cancers have a high mortality rate worldwide, and the progression of the disease is related to cancer stem cells. Until now, its relationship with the microenvironment has been poorly understood. We describe the molecules and different pathways activated during this interaction and the new targeting therapies for cancer cells and microenvironment modulation. This approach could impact the way gastrointestinal cancers are managed.

Abstract

Gastrointestinal adenocarcinomas are one of the world’s deadliest cancers. Cancer stem cells and the tissue microenvironment are highly regulated by cell and molecular mechanisms. Cancer stem cells are essential for maintenance and progression and are associated with resistance to conventional treatments. This article reviews the current knowledge of the role of the microenvironment during the primary establishment of gastrointestinal adenocarcinomas in the stomach, colon, and rectum and its relationship with cancer stem cells. We also describe novel developments in cancer therapeutics, such as targeted therapy, and discuss the advantages and disadvantages of different treatments for improving gastrointestinal cancer prognosis.

Regulation of wound healing and fibrosis by galectins

Galectins are a family of proteins with at least one carbohydrate-recognition domain. Galectins are present in various tissues and organs and participate in different physiological and pathological molecular reactions in vivo. Wound healing is the basic process of traumatic disease recovery. Wound healing involves three overlapping stages: inflammation, proliferation, and remodelling. Furthermore, a comparison of wound healing with the tumour microenvironment revealed that galectin plays a key role in the wound healing process. The current review describes the role of galectin in inflammation, angiogenesis, re-epithelialisation, and fibrous scar formation and evaluates its potential as a therapeutic drug for wounds.

Overexpression of galectin2 (LGALS2) predicts a better prognosis in human breast cancer

BACKGROUND

Galectins (LGALS) are a family of carbohydrate-binding proteins, and LGALS family members have shown prognostic roles in various types of cancers. However, the prognostic significance of some LGALS family members has not been studied in breast malignancy.

METHODS

The prognostic value of LGALS family mRNA expression in breast cancer patients was investigated according to distinct clinicopathological features (including lymph node, intrinsic subtype, pathological grade, HER2, and TP53 status) using the Kaplan-Meier plotter database. Quantitative real-time polymerase chain reaction and western blotting were used to detect the mRNA and protein expression of LGALS in breast cancer and normal breast cells. The aberrant expression of specific LGALS and its correlation with breast cancer outcomes remains elusive. In the present analysis, we comprehensively explored an immunohistochemistry-based map of protein expression profiles in normal tissues, cancer, and cell lines from the widely available Human Protein Atlas (HPA) database. Immunohistochemistry was applied to evaluate the expression of LGALS between cancer and normal tissues.

RESULTS

Our results showed that overexpression of LGALS2 mRNA were correlated with satisfactory overall survival among all breast cancer patients. Furthermore, LGALS2 and LGALS4 expression correlated with a better overall survival (OS) in grade III breast cancer patients; LGALS2 also predicted a better OS in basal-like subtype patients, luminal B patients, HER2-overexpressing patients, TP53 mutated and wild breast cancer patients. Notably, the mRNA and protein expression levels of LGALS2 were decreased in cancer cells compared with normal cells (P<0.05). Furthermore, LGALS2 expression in immunostaining score was lower in cancer tissues than in normal tissues (P<0.005).

CONCLUSION

In conclusion, LGALS2 has potential as a valuable biomarker for envisaging a satisfactory prognosis in patients with breast tumours, particularly those with luminal and basal B types, all stages and grade III tumours.

Single-cell transcriptomics reveals a low CD8+ T cell infiltrating state mediated by fibroblasts in recurrent renal cell carcinoma

Purpose

Recurrent renal cell carcinoma(reRCC) is associated with poor prognosis and the underlying mechanism is not yet clear. A comprehensive understanding of tumor microenvironment (TME) of reRCC may aid in designing effective anticancer therapies, including immunotherapies. Single-cell transcriptomics holds great promise for investigating the TME, however, this technique has not been used in reRCC. Here, we aimed to explore the difference in the TME and gene expression pattern between primary RCC (pRCC) and reRCC at single-cell level.

Experimental design

We performed single-cell RNA sequencing analyses of 32,073 cells from 2 pRCC, 2 reRCC, and 3 adjacent normal kidney samples. 41 pairs of pRCC and reRCC samples were collected as a validation cohort to assess differences observed in single-cell sequencing. The prognostic significance of related cells and markers were studied in 47 RCC patients underwent immunotherapy. The function of related cells and markers were validated via in vitro and in vivo experiments.

Results

reRCC had reduced CD8⁺ T cells but increased cancer-associated fibroblasts (CAFs) infiltration compared with pRCC. Reduced CD8⁺ T cells and increased CAFs infiltration were significantly associated with a worse response from immunotherapy. Remarkably, CAFs showed substantial expression of LGALS1 (Gal1). In vitro, CAFs could induce CD8⁺ T cells apoptosis via Gal1. In vivo, knockdown of Gal1 in CAFs suppressed tumor growth, increased CD8⁺ T cells infiltration, reduced the proportion of apoptotic CD8⁺ T cells and enhanced the efficacy of immunotherapy.

Conclusions

We delineated the heterogeneity of reRCC and highlighted an innovative mechanism that CAFs acted as a suppressor of CD8⁺ T cells via Gal1. Targeting Gal1 combined with anti-PD1 showed promising efficacy in treating RCC.

Galectin expression detected by 68Ga-galectracer PET as a predictive biomarker of radiotherapy resistance

PURPOSE

Hypoxia is a hallmark of solid tumors that is related to radiotherapy resistance. As galectin members, such as galectin-1 and galectin-3, are associated with tumor hypoxia, herein we aimed to investigate whether positron emission tomography (PET) imaging of galectin expression can be employed to effectively pinpoint tumor hypoxia, and to predict radiotherapy resistance.

METHODS

We synthesized a galectin-targeting radiotracer, designated ⁶⁸Ga-galectracer, by radiolabeling a thiodigalactoside derivative. The properties of ⁶⁸Ga-galectracer for PET imaging of tumor hypoxia were characterized in three tumor hypoxia mouse models. Additionally, preliminary PET/CT was performed in two patients with lung cancer to investigate the potential application of ⁶⁸Ga-galectracer for clinical imaging.

RESULTS

High-contrast imaging was achieved in the murine acute hypoxia tumor model, A549 natural hypoxia model, and sorafenib treatment-induced hypoxic 4T1 tumor model by PET using ⁶⁸Ga-galectracer. In fact, ⁶⁸Ga-galectracer exhibited superior hypoxia detection to that of ¹⁸F-misonidazole in the 4T1 tumors. Moreover, tumors with high galectin expression levels, as detected by ⁶⁸Ga-galectracer PET, exhibited significantly lower responses to subsequent radiotherapy compared to those with low galectin expression levels. In patients with lung cancer, PET imaging using ⁶⁸Ga-galectracer provided data that were complementary to that of the glucose metabolic PET radiotracer ¹⁸F-fluorodeoxyglucose.

CONCLUSION

⁶⁸Ga-galectracer is a promising radiotracer for PET-based imaging of tumor hypoxia in vivo. Thus, hypoxia PET with ⁶⁸Ga-galectracer could provide a noninvasive approach to proactively predict radiotherapy efficacy.

TRIAL REGISTRATION

Chictr.org.cn (ChiCTR2000029522). Registered 03 February 2020.

The impact of hypoxia on immune state in cancer

Hypoxia is a known feature of solid tumors and a critical promoter of tumor hallmarks. Hypoxia influences tumor immunity in a way favoring immune evasion and resistance. Extreme hypoxia and aberrant hypoxia-inducible factor-1 (HIF-1) activity in tumor microenvironment (TME) is a drawback for effective immunotherapy. Infiltration and activity of CD8⁺ T cells is reduced in such condition, whereas regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs) show high activities. Highly hypoxic TME also impairs maturation and activity of dendritic cell (DCs) and natural killer (NK) cells. In addition, the hypoxic TME positively is linked positively with metabolic changes in cells of immune system. These alterations are indicative of a need for hypoxia modulation as a complementary targeting strategy to go with immune checkpoint inhibitor (ICI) therapy.

Site-Specific Cross-Linking of Galectin-1 Homodimers via Poly(ethylene glycol) Bismaleimide

Introduction

The promise of the natural immunoregulator, Galectin-1 (Gal1), as an immunomodulatory therapeutic is challenged by its unstable homodimeric conformation. Previously, a Gal1 homodimer stabilized via covalent poly(ethylene glycol) diacrylate (PEGDA) cross-linking demonstrated higher activity relative to the non-covalent homodimer.

Methods

Here, we report Gal1 homodimers formed using an alternative thiol-Michael addition linker chemistry.

Results

Poly(ethylene glycol) bismaleimide (PEGbisMal) reacted with Gal1 at multiple sites with greater efficiency than PEGDA. However, multiple PEGbisMal molecules were conjugated to Gal1 C130, a Gal1 mutant with one surface cysteine (cys-130) and two cysteines thought to be buried in the solvent-inaccessible protein core (cys-42 and cys-60). Site-directed mutagenesis demonstrated that cys-60 was the site at which additional PEGbisMal molecules were conjugated onto Gal1 C130. Compared to WT-Gal1, Gal1 C130 had low activity for inducing Jurkat T cell death, characterized by phosphatidylserine exposure and membrane permeability. PEG cross-linking could restore the function of Gal1 C130, such that at high concentrations Gal1 C130 cross-linked by PEGbisMal had higher activity than both WT-Gal1 and Gal1 C130 cross-linked by PEGDA. Mutating cys-42 and cys-60 to serines in Gal1 C130 did not affect the cell death signaling activity of the Gal1 C130 homodimer cross-linked by PEGbisMal. PEGylated Gal1 C130 variants also eliminated the need for a reducing agent, such as dithiothreitol, which is required to maintain WT-Gal1 signaling activity.

Conclusion

Collectively, these data demonstrate that thiol-Michael addition bioconjugation leads to a PEG-cross-linked Gal1 homodimer with improved extracellular signaling activity that does not require a reducing environment to be functional.

Reactive Oxygen Species Mediate 6c-Induced Mitochondrial and Lysosomal Dysfunction, Autophagic Cell Death, and DNA Damage in Hepatocellular Carcinoma

Increasing the level of reactive oxygen species (ROS) in cancer cells has been suggested as a viable approach to cancer therapy. Our previous study has demonstrated that mitochondria-targeted flavone-naphthalimide-polyamine conjugate 6c elevates the level of ROS in cancer cells. However, the detailed role of ROS in 6c-treated cancer cells is not clearly stated. The biological effects and in-depth mechanisms of 6c in cancer cells need to be further investigated. In this study, we confirmed that mitochondria are the main source of 6c-induced ROS, as demonstrated by an increase in 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) and MitoSox fluorescence. Compound 6c-induced mitochondrial ROS caused mitochondrial dysfunction and lysosomal destabilization confirmed by absolute quantitation (iTRAQ)-based comparative proteomics. Compound 6c-induced metabolic pathway dysfunction and lysosomal destabilization was attenuated by N-acetyl-L-cysteine (NAC). iTRAQ-based comparative proteomics showed that ROS regulated the expression of 6c-mediated proteins, and treatment with 6c promoted the formation of autophagosomes depending on ROS. Compound 6c-induced DNA damage was characterized by comet assay, p53 phosphorylation, and γH2A.X, which was diminished by pretreatment with NAC. Compound 6c-induced cell death was partially reversed by 3-methyladenine (3-MA), bafilomycin (BAF) A1, and NAC, respectively. Taken together, the data obtained in our study highlighted the involvement of mitochondrial ROS in 6c-induced autophagic cell death, mitochondrial and lysosomal dysfunction, and DNA damage.

Reprogramming the tumor metastasis cascade by targeting galectin-driven networks

A sequence of interconnected events known as the metastatic cascade promotes tumor progression by regulating cellular and molecular interactions between tumor, stromal, endothelial, and immune cells both locally and systemically. Recently, a new concept has emerged to better describe this process by defining four attributes that metastatic cells should undergo. Every individual hallmark represents a unique trait of a metastatic cell that impacts directly in the outcome of the metastasis process. These critical features, known as the hallmarks of metastasis, include motility and invasion, modulation of the microenvironment, cell plasticity and colonization. They are hierarchically regulated at different levels by several factors, including galectins, a highly conserved family of β-galactoside-binding proteins abundantly expressed in tumor microenvironments and sites of metastasis. In this review, we discuss the role of galectins in modulating each hallmark of metastasis, highlighting novel therapeutic opportunities for treating the metastatic disease.

Targeting galectins in T cell-based immunotherapy within tumor microenvironment

Over the past few years, tumor immunotherapy has emerged as an innovative tumor treatment and owned incomparable advantages over other tumor therapy. With unique complexity and uncertainty, immunotherapy still need helper to apply in the clinic. Galectins, modulated in tumor microenvironment, can regulate the disorders of innate and adaptive immune system resisting tumor growth. Considering the role of galectins in tumor immunosuppression, combination therapy of targeted anti-galectins and immunotherapy may be a promising tumor treatment. This brief review summarizes the expression and immune functions of different galectins in tumor microenvironment and discusses the potential value of anti-galectins in combination with checkpoint inhibitors in tumor immunotherapy.

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.

Insights into the role of sialylation in cancer progression and metastasis

Upregulation of sialyltransferases—the enzymes responsible for the addition of sialic acid to growing glycoconjugate chains—and the resultant hypersialylation of up to 40–60% of tumour cell surfaces are established hallmarks of several cancers, including lung, breast, ovarian, pancreatic and prostate cancer. Hypersialylation promotes tumour metastasis by several routes, including enhancing immune evasion and tumour cell survival, and stimulating tumour invasion and migration. The critical role of enzymes that regulate sialic acid in tumour cell growth and metastasis points towards targeting sialylation as a potential new anti-metastatic cancer treatment strategy. Herein, we explore insights into the mechanisms by which hypersialylation plays a role in promoting metastasis, and explore the current state of sialyltransferase inhibitor development.

Single-Cell RNA-seq Reveals Obesity-Induced Alterations in the Brca1-Mutated Mammary Gland Microenvironment

Clinical and experimental studies have shown that obesity increases the development and progression of breast cancer. The impact of obesity on the tumor microenvironment plays an important role in tumorigenesis, yet the precise mechanisms underlying obesity-mediated effects on cell-to-cell communication within the tumor microenvironment have been difficult to define. In this study, we conducted single-cell RNA sequencing (scRNA-seq) studies to investigate the impact of high-fat diet (HFD)-induced obesity on transcriptomic landscapes of stromal and immune cells in mammary glands of Brca1−/−; p53+/− mice, an animal breast cancer model. Hierarchical clustering and gene pathway enrichment analyses of scRNA-seq data showed that five different subtypes of stromal fibroblasts existed in mouse Brca1-mutated mammary glands. HFD-induced obesity led to upregulated expression of extracellular matrix (ECM) genes (Col3a1, Col6a3, Eln, and Sparc) and downregulated expression of immunoregulatory genes (Iigp1 and Cxcl10) in these stromal subtype cells. These findings, taken together, suggest that obesity alters the ECM composition and immune ecosystem through modulating the functionality of mammary stromal fibroblasts. Moreover, scRNA-seq analysis of mammary immune cells indicated that HFD-induced obesity promoted the generation and/or recruiting of pro-tumorigenic M2 macrophages in mammary glands. Our studies provide new insight into a mechanistic paradigm wherein obesity modulates the functions of stromal and immune cells to create the tumorigenic microenvironment for promoting breast tumorigenesis.

Glycogen as a Building Block for Advanced Biological Materials

Biological nanoparticles found in living systems possess distinct molecular architectures and diverse functions. Glycogen is a unique biological polysaccharide nanoparticle fabricated by nature through a bottom-up approach. The biocatalytic synthesis of glycogen has evolved over time to form a nanometer-sized dendrimer-like structure (20-150 nm) with a highly branched surface and a dense core. This makes glycogen markedly different from other natural linear or branched polysaccharides and particularly attractive as a platform for biomedical applications. Glycogen is inherently biodegradable, nontoxic, and can be functionalized with diverse surface and internal motifs for enhanced biofunctional properties. Recently, there has been growing interest in glycogen as a natural alternative to synthetic polymers and nanoparticles in a range of applications. Herein, the recent literature on glycogen in the material-based sciences, including its use as a constituent in biodegradable hydrogels and fibers, drug delivery vectors, tumor targeting and penetrating nanoparticles, immunomodulators, vaccine adjuvants, and contrast agents, is reviewed. The various methods of chemical functionalization and physical assembly of glycogen nanoparticles into multicomponent nanodevices, which advance glycogen toward a functional therapeutic nanoparticle from nature and back again, are discussed in detail.

Molecular Imaging of Galectin-1 Expression as a Biomarker of Papillary Thyroid Cancer by Using Peptide-Functionalized Imaging Probes

Thyroid cancers are the most frequent endocrine cancers and their incidence is increasing worldwide. Thyroid nodules occur in over 19–68% of the population, but only 7–15% of them are diagnosed as malignant. Diagnosis relies on a fine needle aspiration biopsy, which is often inconclusive and about 90% of thyroidectomies are performed for benign lesions. Galectin-1 has been proposed as a confident biomarker for the discrimination of malignant from benign nodules. We previously identified by phage display two peptides (P1 and P7) targeting galectin-1, with the goal of developing imaging probes for non-invasive diagnosis of thyroid cancer. The peptides were coupled to ultra-small superparamagnetic particles of iron oxide (USPIO) or to a near-infrared dye (CF770) for non-invasive detection of galectin-1 expression in a mouse model of papillary thyroid cancer (PTC, as the most frequent one) by magnetic resonance imaging and fluorescence lifetime imaging. The imaging probes functionalized with the two peptides presented comparable image enhancement characteristics. However, those coupled to P7 were more favorable, and showed decreased retention by the liver and spleen (known for their galectin-1 expression) and high sensitivity (75%) and specificity (100%) of PTC detection, which confirm the aptitude of this peptide to discriminate human malignant from benign nodules (80% sensitivity, 100% specificity) previously observed by immunohistochemistry.

Synthesis of tricyclic carbohydrate–benzene hybrids as selective inhibitors of galectin-1 and galectin-8 N-terminal domains

As the galactoside binding family of galectin proteins is involved in many physiological and pathological processes, the inhibitors of these proteins are considered to be of significant interest in the treatment of diseases such as cancer and fibrosis. Herein, fused tricyclic carbohydrate–benzene hybrid core structures are reported to be the selective inhibitors of galectin-1 and the N-terminal domain of galectin-8 by a competitive fluorescence polarization assay. The key intermediates mono- or diiodo tricyclic carbohydrate–benzene hybrids were synthesized from protected 2-bromo-3-O-propargyl-d-galactose via a domino reaction and subsequently utilized for further derivatization by Stille couplings to achieve derivatives carrying substituents at C10 and/or C11. Several compounds showed affinity for the galectin-1 and galectin-8 N-terminal (8N) domains; however, weak or even no binding was observed for galectin-3. Monosubstituted derivatives at C10 or C11 exhibited better affinity for galectin-8N than di-substituted derivatives at C10 or C11. Especially, a benzyl substituent or p-fluorobenzyl substituent at C11 displayed affinity and selectivity for galectin-1 and galectin-8N over galectin-3. This suggests that tricyclic carbohydrate–benzene hybrids are promising scaffolds for the development of selective galectin-1 and galectin-8N inhibitors.

Fused tricyclic carbohydrate–benzene hybrids carrying substituents at C10 and/or C11 were designed, synthesized and evaluated as inhibitors for galectin-1 and the N-terminal domain of galectin-8.

Identification of Predictive Proteins and Biological Pathways for the Tumorigenicity of Vestibular Schwannoma by Proteomic Profiling

PURPOSE

Vestibular schwannomas (VSs) are benign tumors that account for 8-10% of all intracranial tumors. So far, the tumorigenesis of VS has not been fully elucidated. This study is designed to identify differently expressed proteins involved in VS tumorigenesis.

EXPERIMENTAL DESIGN

An isobaric tag is used for relative and absolute quantification (iTRAQ) approach to characterize the protein expression profiles from pooled VS tissues (n = 12) and pooled matched normal vestibular tissues (n = 12).

RESULTS

A total of 933 differentially expressed proteins are identified between VS and the matched normal vestibular tissues, with 489 being upregulated and 444 being downregulated. Bioinformatics analyses are performed according to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses. Several of the differentially expressed proteins are validated by western blotting analyses, and upregulation of LGALS1, ANXA1, GRB2, and STAT1 is validated in VS tissue by immunohistochemistry.

CONCLUSIONS AND CLINICAL RELEVANCE

The study represents the successful application of iTRAQ technology to an investigation of VS. Many of the differentially expressed proteins identified here have not been linked to VS before, and these dysregulated proteins may provide potential biomarkers for human VS diagnosis.

State of the art in immunotherapy of neuroblastoma

Neuroblastoma (NB) is a common and deadly malignancy mostly observed in children. Evolution of therapeutic options for NB led to the addition of immunotherapeutic modalities to the previously recruited chemotherapeutic options. Molecular studies of the NB cells resulted in the discovery of many tumor-associated genes and antigens such as MYCN gene and GD2. MYCN gene and GD2 surface antigen are two of the most practical discoveries regarding immunotherapy of neuroblastoma. The GD2 antigen has been targeted in many animal and human studies including Phase III clinical trials. Even though these antigens have changed the face of pediatric neuroblastoma, they do not take as much credit in immunotherapy of adult-onset neuroblastoma. Monoclonal antibodies have been designed to detect this antigen on the surface of NB tumor cells. Despite bettering the outcomes for NB patients, current therapies still fail in many cases. Studies are underway to discover more specific tumor-associated antigens and more effective treatment options. In the current narrative, immunotherapy of NB - from emerging of this therapeutic backbone in NB to the latest discoveries regarding this malignancy - has been reviewed.

Phostine 3.1a as a pharmacological compound with antiangiogenic properties against diseases with excess vascularization

Angiogenesis is a complex process leading to the growth of new blood vessels from existing vasculature, triggered by local proangiogenic factors such as VEGF. An excess of angiogenesis is a recurrent feature of various pathologic conditions such as tumor growth. Phostines are a family of synthetic glycomimetic compounds that exhibit anticancer properties, and the lead compound 3-hydroxy-4,5-bis-benzyloxy-6-benzyloxymethyl-2-phenyl2-oxo-2λ5-[1,2]oxaphosphinane (PST 3.1a) shows antiglioblastoma properties both in vitro and in vivo. In the present study, we assessed the effect of PST 3.1a on angiogenesis and endothelial metabolism. In vitro, PST 3.1a (10 µM) inhibited all steps that regulate angiogenesis, including migration, proliferation, adhesion, and tube formation. In vivo, PST 3.1a reduced intersegmental vessel formation and vascularization of the subintestinal plexus in zebrafish embryos and also altered pathologic angiogenesis and glioblastoma progression in vivo. Mechanistically, PST 3.1a altered interaction of VEGF receptor 2 and glycosylation-regulating protein galectin-1, a key component regulating angiogenesis associated with tumor resistance. Thus, these data show that use of PST 3.1a is an innovative approach to target angiogenesis.-Bousseau, S., Marchand, M., Soleti, R., Vergori, L., Hilairet, G., Recoquillon, S., Le Mao, M., Gueguen, N., Khiati, S., Clarion, L., Bakalara, N., Martinez, M. C., Germain, S., Lenaers, G., Andriantsitohaina, R. Phostine 3.1a as a pharmacological compound with antiangiogenic properties against diseases with excess vascularization.

Increased Galectin-1 Expression in Thymic Epithelial Tumors

INTRODUCTION

Thymic epithelial tumors (TET) are rare malignancies with a paucity of data on biology and therapeutics. Galectin-1 is a member of the β-galactoside binding protein family and has been shown to mediate tumor growth via modulation of immune cell function. This study examined galectin-1 expression in TET.

PATIENTS AND METHODS

A tissue microarray of 68 patients with TET and 8 benign thymus controls were stained for galectin-1 expression and scored by a pathologist blinded to patient clinical and pathologic data. Galectin-1 expression +1 or greater staining intensity was considered positive. Clinical and pathologic data were abstracted from institutional databases. Expression of galectin-1 in thymic tumor was compared to benign thymus controls and correlated with pertinent clinical and pathologic data.

RESULTS

Galectin-1 expression was higher in TET compared to benign thymus controls (65% vs. 0%). No significant association between galectin-1 expression and the development of recurrent disease, paraneoplastic syndromes, or overall survival was noted.

CONCLUSION

Galectin-1 is overexpressed in the majority of TET. Detection of galectin-1 may differentiate benign from neoplastic thymic processes. Additional studies are needed to assess the role of galectin-1 in the development of TET.

Human Galectin-1 Improves Sarcolemma Stability and Muscle Vascularization in the mdx Mouse Model of Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is a devastating disease caused by mutations in the dystrophin gene that result in the complete absence of dystrophin protein. We have shown previously that recombinant mouse Galectin-1 treatment improves physiological and histological outcome measures in the mdx mouse model of DMD. Because recombinant human Galectin-1 (rHsGal1) will be used to treat DMD patients, we performed a dose-ranging study and intraperitoneal or intravenous delivery to determine the efficacy of rHsGal1 to improve preclinical outcome measures in mdx mice. Our studies showed that the optimal dose of rHsGal1 delivered intraperitoneally was 20 mg/kg and that this treatment improved muscle strength, sarcolemma stability, and capillary density in skeletal muscle. We next examined the efficacy of intravenous delivery and found that a dose of 2.5 mg/kg rHsGal1 was well tolerated and improved outcome measures in the mdx mouse model. Our studies identified that intravenous doses of rHsGal1 exceeding 2.5 mg/kg resulted in toxicity, indicating that dosing using this delivery mechanism will need to be carefully monitored. Our results support the idea that rHsGal1 treatment can improve outcome measures in the mdx mouse model and support further development as a potential therapeutic agent for DMD.

Endogenous Galectin-1 in T Lymphocytes Regulates Anti-prostate Cancer Immunity

The identification of effective new therapies for prostate cancer (PCa) requires a better understanding of the multiple molecular interactions between tumor cells and their associated microenvironment. In this context, galectin-1 (Gal-1) is a key molecule in the determination of the prostatic carcinoma microenviroment; therefore, it is essential to understand all the molecular processes in which this protein is involved. Most of the previous studies found in the literature have focused on the microenvironment remodeling properties of tumor-secreted Gal-1, through its interactions with the glyco-receptors at the cell membrane and the extracellular matrix. This report shows original aspects of the lectin by focusing on the role of lymphocyte endogenous Gal-1 in controlling anti-prostate tumor immunity. Using a murine preclinical model of prostate cancer, our results demonstrate that endogenous Gal-1 in lymphocytes modulates their proliferative rate and cytotoxic function in conditions of high extracellular Gal-1 concentration, mainly derived from tumor cells. In such conditions, the absence of Gal-1 in T lymphocytes potentiates anti-tumor immune responses. Further studies demonstrated that endogenous Gal-1 in CD4+, but mainly in CD8+T cells, acts as a negative regulator of anti-tumor immunity. In conclusion, prostate tumors require Gal-1 in lymphocytes to evade immune responses. This report lays the foundation for an original immunotherapy strategy for prostate cancer.

Galectins as regulators of cell survival in the leukemia niche

The microenvironment within the bone marrow (BM) contains support cells that promote leukemia cell survival and suppress host anti-tumor defenses. Galectins are a family of beta-galactoside binding proteins that are critical components in the tumor microenvironment. Galectin 1 (LGALS1) and Galectin 3 (LGALS3) as regulators of RAS signaling intracellularly and as inhibitors of immune cells extracellularly are perhaps the best studied members for their role in leukemia biology. Interest in Galectin 9 (LGALS9) is growing as this galectin has been identified as an immune checkpoint molecule. LGALS9 also supports leukemia stem cells (LSCs) though a mechanism of action is not clear. LGALS1 and LGALS3 each participate in a diverse number of survival pathways that promote drug resistance by supporting pro-tumor molecules such BCL2, MCL-1, and MYC and blocking tumor suppressors like p53. Acute myeloid leukemia (AML) BM mesenchymal stromal cells (MSC) have protein signatures that differ from healthy donor MSC. Elevated LGALS3 protein in AML MSC is associated with refractory disease/relapse demonstrating that MSC derived galectin impacts patient survival. LGALS3 is a critical determining factor whether MSC differentiate into adipocytes or osteoblasts so the galectin influences the cellular composition of the leukemia niche. Both LGALS3 and LGALS1 when secreted can suppress immune function. Both galectins can induce apoptosis of T cells. LGALS3 also modulates T cell receptor endocytosis and impairs interferon mediated chemokine production by binding glycosylated interferon. LGALS3 as a TIM3 binding partner acts to suppress T cell function. Galectins also impact leukemia cell mobilization and may participate in homing mechanisms. LGALS3 participates in transport mechanism of integrins, receptors, and other molecules that control cell adhesion and cell:cell interactions. The diversity of these various functions demonstrate the importance of these galectins in the leukemia niche. This review will cover the role of LGALS1, LGALS3, and LGALS9 in the various processes that are critical for maintaining leukemia cells in the tumor microenvironment.

Upregulation of LGALS1 is associated with oral cancer metastasis

Background

Oral cancer metastasis is a devastating process that contributes to poor prognosis and high mortality, yet its detailed underlying mechanisms remain unclear. Here, we aimed to evaluate metastasis-specific markers in oral cancer and to provide comprehensive recognition concerning functional roles of the specific target in oral cancer metastasis.

Methods

Lectin, galactoside-binding, soluble, 1 (LGALS1) was identified by secretomic analysis. LGALS1 expression of patient samples with oral cancer on the tissue microarray were examined by immunochemical (IHC) staining. Small interfering RNA (siRNA)-mediated knockdown of LGALS1 revealed the role of LGALS1 in oral cancer metastasis in vitro and in vivo.

Results

LGALS1 was observed to be upregulated in highly invasive oral cancer cells, and elevated LGALS1 expression was correlated with cancer progression and lymph node metastasis in oral cancer tissue specimens. Functionally, silencing LGALS1 resulted in suppressed cell growth, wound healing, cell migration, and cell invasion in oral cancer cells in vitro. Knockdown of LGALS1 in highly invasive oral cancer cells dramatically inhibited lung metastasis in an in vivo mouse model. Mechanistic studies suggested p38 mitogen-activated protein kinase (MAPK) phosphorylation, upregulated MMP-9, and mesenchymal phenotypes of epithelial-mesenchymal transition (EMT) in highly invasive oral cancer cells, whereas siRNA against LGALS1 resulted in the inactivation of p38 MAPK pathway, downregulated MMP-9, and EMT inhibition.

Conclusions

These findings demonstrate that elevated LGALS1 is strongly correlated with oral cancer progression and metastasis, and that it could potentially serve as a prognostic biomarker and an innovative target for oral cancer therapy.

Lactulose as a novel template for anticancer drug development targeting galectins

Galectins are carbohydrate binding proteins (lectins), which characteristically bind β-galactosides. Galectins play a role in tumour progression through involvement in proliferation, metastasis, angiogenesis, immune evasion and drug resistance. There is need for inhibitors (antagonists) that are specific for distinct galectins and that can interfere with galectin-carbohydrate interactions during cancer progression. Here, we propose that lactulose, a non-digestible galactose-fructose disaccharide, presents a novel inhibitor scaffold for design of inhibitors against galectins. Thermodynamic evaluation displays binding affinity of lactulose against the galectin-1 and galectin-3 carbohydrate recognition domain (CRD). Crystal structures of galectin-1 and galectin-3 in complex with lactulose reveal for the first time the molecular basis of the galectin-lactulose interactions. Molecular modelling was implemented to propose novel lactulose derivatives as potent anti-cancer agents.

The Role of Galectins in Cervical Cancer Biology and Progression

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

A novel self-assembled nanoparticle platform based on pectin-eight-arm polyethylene glycol-drug conjugates for co-delivery of anticancer drugs

The application of non-toxic carriers to increase drug loading, multi-drug delivery, and extremely small size of nano-drugs to construct a tremendous transmission system is the goal for all researchers to be pursued. The proposal of natural pectin nano-platform for delivery of multiple drugs is critical for biomedical research, especially a particle size of below 100nm with high yield. Here we design a new core-shell structure pectin-eight-arm polyethylene glycol-ursolic acid/hydrooxycampothecin nanoparticle (Pec-8PUH NPs) through a special self-assembly method for stabilizing and dispersing particles, improving water-solubility, and achieving drug controlled release. The obtained Pec-8PUH NPs possessed appropriate size (~91nm), drug-loaded efficiency and encapsulation efficiency through the regulation of eight-arm polyethylene glycol. In addition, Pec-8PUH NPs could enhance cell cytotoxicity, shorten blood retention time (7.3-fold UA, 7.2-fold HCPT) and more effective cellular uptake than free drugs, which exhibited an obvious synergistic effect of UA and HCPT by the co-delivery. 4T1 tumor-bearing mice also showed a higher survival rate than free UA and free HCPT. The result further shows that this novel drug delivery system has a promising potential for anti-cancer combination therapy.

Self-Assembled Nanoparticles Platform Based on Pectin-Dihydroartemisinin Conjugates for Codelivery of Anticancer Drugs

Natural pectin is an important carrier for delivering drugs in biomedical research, however, there are only a few reports on the preparation of pectin nanoparticles, especially a particle size of below 100 nm with high yield. Here we design pectin-dihydroartemisinin/hydrooxycampothecin nanoparticles (PDC-H NPs) through a self-assembly method. The prepared PDC-H NPs contained hydrophilic part of pectin and hydrophobic anticancer drugs of dihydroartemisinin and hydroxycamptothecin, which could increase drug loading, improve water solubility, and achieve controlled release of drugs. The results indicated that the particle size of PDC-H NPs was about 70 nm, drug-loaded efficiency of DHA was 20.33 wt %, and encapsulation efficiency of HCPT was 14.11 wt %. PDC-H NPs exhibited a higher cytotoxicity, the blood retention time of PDC-H NPs was 4.8-fold longer than DHA and was 6.8-fold longer than HCPT. In addition, effective cellular uptake exhibited an obvious synergistic effect compared with DHA and HCPT. 4T1 tumor-bearing mice also showed a higher survival rate than free DHA and free HCPT. The result show that the self-assembled PDC-H NPs is a promising anticancer drug for codelivery.

TrkB-Target Galectin-1 Impairs Immune Activation and Radiation Responses in Neuroblastoma: Implications for Tumour Therapy

Galectin-1 (Gal-1) has been described to promote tumour growth by inducing angiogenesis and to contribute to the tumour immune escape. We had previously identified up-regulation of Gal-1 in preclinical models of aggressive neuroblastoma (NB), the most common extracranial tumour of childhood. While Gal-1 did not confer a survival advantage in the absence of exogenous stressors, Gal-1 contributed to enhanced cell migratory and invasive properties. Here, we review these findings and extend them by analyzing Gal-1 mediated effects on immune cell regulation and radiation resistance. In line with previous results, cell autonomous effects as well as paracrine functions contribute to Gal-1 mediated pro-tumourigenic functions. Interfering with Gal-1 functions in vivo will add to a better understanding of the role of the Gal-1 axis in the complex tumour-host interaction during immune-, chemo- and radiotherapy of neuroblastoma.

Hallmarks of glycosylation in cancer

Aberrant glycosylation plays a fundamental role in key pathological steps of tumour development and progression. Glycans have roles in cancer cell signalling, tumour cell dissociation and invasion, cell-matrix interactions, angiogenesis, metastasis and immune modulation. Aberrant glycosylation is often cited as a ‘hallmark of cancer’ but is notably absent from both the original hallmarks of cancer and from the next generation of emerging hallmarks. This review discusses how glycosylation is clearly an enabling characteristic that is causally associated with the acquisition of all the hallmark capabilities. Rather than aberrant glycosylation being itself a hallmark of cancer, another perspective is that glycans play a role in every recognised cancer hallmark.

Galectin Targeted Therapy in Oncology: Current Knowledge and Perspectives

The incidence and mortality of cancer have increased over the past decades. Significant progress has been made in understanding the underpinnings of this disease and developing therapies. Despite this, cancer still remains a major therapeutic challenge. Current therapeutic research has targeted several aspects of the disease such as cancer development, growth, angiogenesis and metastases. Many molecular and cellular mechanisms remain unknown and current therapies have so far failed to meet their intended potential. Recent studies show that glycans, especially oligosaccharide chains, may play a role in carcinogenesis as recognition patterns for galectins. Galectins are members of the lectin family, which show high affinity for β-galactosides. The galectin–glycan conjugate plays a fundamental role in metastasis, angiogenesis, tumor immunity, proliferation and apoptosis. Galectins’ action is mediated by a structure containing at least one carbohydrate recognition domain (CRD). The potential prognostic value of galectins has been described in several neoplasms and helps clinicians predict disease outcome and determine therapeutic interventions. Currently, new therapeutic strategies involve the use of inhibitors such as competitive carbohydrates, small non-carbohydrate binding molecules and antibodies. This review outlines our current knowledge regarding the mechanism of action and potential therapy implications of galectins in cancer.

Role of Galectins in Multiple Myeloma

Galectins are a family of lectins that bind β-galactose-containing glycoconjugates and are characterized by carbohydrate-recognition domains (CRDs). Galectins exploit several biological functions, including angiogenesis, regulation of immune cell activities and cell adhesion, in both physiological and pathological processes, as tumor progression. Multiple myeloma (MM) is a plasma cell (PC) malignancy characterized by the tight adhesion between tumoral PCs and bone marrow (BM) microenvironment, leading to the increase of PC survival and drug resistance, MM-induced neo-angiogenesis, immunosuppression and osteolytic bone lesions. In this review, we explore the expression profiles and the roles of galectin-1, galectin-3, galectin-8 and galectin-9 in the pathophysiology of MM. We focus on the role of these lectins in the interplay between MM and BM microenvironment cells showing their involvement in MM progression mainly through the regulation of PC survival and MM-induced angiogenesis and osteoclastogenesis. The translational impact of these pre-clinical pieces of evidence is supported by recent data that indicate galectins could be new attractive targets to block MM cell growth in vivo and by the evidence that the expression levels of LGALS1 and LGALS8, genes encoding for galectin-1 and galectin-8 respectively, correlate to MM patients’ survival.

How Signaling Molecules Regulate Tumor Microenvironment: Parallels to Wound Repair

It is now suggested that the inhibition of biological programs that are associated with the tumor microenvironment may be critical to the diagnostics, prevention and treatment of cancer. On the other hand, a suitable wound microenvironment would accelerate tissue repair and prevent extensive scar formation. In the present review paper, we define key signaling molecules (growth factors, cytokines, chemokines, and galectins) involved in the formation of the tumor microenvironment that decrease overall survival and increase drug resistance in cancer suffering patients. Additional attention will also be given to show whether targeted modulation of these regulators promote tissue regeneration and wound management. Whole-genome transcriptome profiling, in vitro and animal experiments revealed that interleukin 6, interleukin 8, chemokine (C-X-C motif) ligand 1, galectin-1, and selected proteins of the extracellular matrix (e.g., fibronectin) do have similar regulation during wound healing and tumor growth. Published data demonstrate remarkable similarities between the tumor and wound microenvironments. Therefore, tailor made manipulation of cancer stroma can have important therapeutic consequences. Moreover, better understanding of cancer cell-stroma interaction can help to improve wound healing by supporting granulation tissue formation and process of reepithelization of extensive and chronic wounds as well as prevention of hypertrophic scars and formation of keloids.

Tissue and plasma levels of galectins in patients with high grade serous ovarian carcinoma as new predictive biomarkers

Galectins are moving closer to center stage in detecting glycosylation aberration in cancer cells. Here, we have investigated the expression of galectins in ovarian cancer (OC) and examined their potential as biomarkers in tissues and blood plasma samples of high grade serous ovarian carcinoma (HGSC) patients. In tissues, we found that increased protein expression of stromal gal-1 and epithelial gal-8/9 was associated with a poor response to treatment of HGSC patients. Gal-8/9 were both independent predictors of chemoresistance and overall survival (OS), respectively. This galectin signature increased the predictive value of the cancer antigen 125 (CA125) on 5-year disease-free survival (DFS), post-chemotherapy treatment and 5-year OS. In CA125^LOW patients, epithelial gal-9 was associated with a lower 5-year OS while stromal gal-1 and epithelial gal-8 were both associated with a lower 5-year DFS. Such negative predictive value of gal-8 and gal-9 was also found using plasma samples. In both cases, high plasma levels of gal-8 and gal-9 was associated with a lower OS and DFS. Overall, these data suggest that galectins may be promising biomarkers to identify subgroups of HGSC patients with poorer prognosis. Our study also contributes to better define the heterogeneity of the disease.

Targeted photodynamic therapy of breast cancer cells using lactose-phthalocyanine functionalized gold nanoparticles

Gold nanoparticles (AuNPs), which have been widely used for the delivery of photosensitizers for photodynamic therapy (PDT) of cancer, can be dispersed in aqueous solutions improving the delivery of the hydrophobic photosensitizer into the body. Furthermore, the large surface of AuNPs can be functionalized with a variety of ligands, including proteins, nucleic acids and carbohydrates, that allow selective targeting to cancer tissue. In this study, gold nanoparticles were functionalized with a mixed monolayer of a zinc phthalocyanine and a lactose derivative. For the first time, a carbohydrate was used with a dual purpose, as the stabilizing agent of the gold nanoparticles in aqueous solutions and as the targeting agent for breast cancer cells. The functionalization of the phthalocyanine-AuNPs with lactose led to the production of water-dispersible nanoparticles that are able to generate singlet oxygen and effect cell death upon irradiation. The targeting ability of lactose of the lactose-phthalocyanine functionalized AuNPs was studied in vitro towards the galectin-1 receptor on the surface of breast cancer cells. The targeting studies showed the exciting potential of lactose as a specific targeting agent for galactose-binding receptors overexpressed on breast cancer cells.