The regulation of tolerogenic dendritic cells by a Chinese herb formula improves abortion prone in mice.

BACKGROUND: Abortion prone (AP) is a common clinical event. The underlying mechanism remains unclear. Traditional Chinese formulas are known to be efficient in the management of abortion. The purpose of this study is to observe the effects of Anzitiaochongtang (AZT), a traditional formulation of Chinese medicine, on improving AP in mice by regulating immune tolerance. METHODS: An established abortion model (CBA/J×DBA/2) was employed. AZT was prepared and administered to mice in a manner consistent with clinical practice. Tolerogenic dendritic cells (tDC) and type 1 regulatory T cells (Tr1 cell) in mice were analyzed by immunological approaches to be used as representative immune tolerant parameters. RESULTS: An AP model was established with CBA/J × DBA/2 mice. The expression of IL-10 in tDC and Tr1 cell frequency in the mouse decidua tissues were lower in the AP group than that in the normal pregnancy (NP) group. Administration of AZT up regulated the expression of IL-10 in tDCs and Tr1 cell generation in the decidua tissues, and improved the pregnancy and tissue structure in AP mice. The main mechanism by which AZT improves pregnancy in AP mice is that AZT enhanced the expression of galectin-9 in the epithelial cells of decidua tissues. Galectin 9 activates TIM3 on DCs to promote the IL-10 expression. The DCs induced more Tr1 cells in the decidua tissues. CONCLUSIONS: Dysfunctional tDCs were detected in the AP decidua tissues. Administration of AZT improved pregnancy in AP mice by regulating tDC function and generation of Tr1 cells in the maternal-fetal interface.

O-GlcNAc-Mediated Regulation of Galectin Expression and Secretion in Human Promyelocytic HL-60 Cells Undergoing Neutrophilic Differentiation.

In this study, we have tested the hypothesis that the expression and secretion of galectins are driven through mechanisms globally impacted by homeostatic regulation involving the post-translational modification of intracellular proteins with O-linked N-acetylglucosamine (O-GlcNAc). We showed that neutrophilic differentiation of HL-60 cells induced by all-trans retinoic acid (ATRA) and 6-diazo-5-oxo-L-norleucine (DON) was associated with a significant drop of cellular O-GlcNAc levels in serum-contained and serum-free cell culture media. Galectin gene and protein expression profiles in HL-60 cells were specifically modified by ATRA and by inhibitors of O-GlcNAc cycle enzymes, however overall trends for each drug were similar between cells growing in the presence or absence of serum except for LGALS9 and LGALS12. The secretion of four galectins (-1, -3, -9, and -10) by HL-60 cells in a serum-free medium was stimulated by O-GlcNAc-reducing ATRA and DON while O-GlcNAc-elevating thiamet G (O-GlcNAcase inhibitor) failed to change the basal levels of extracellular galectins. Taken together, these results demonstrate that O-GlcNAc homeostasis is essential not only for regulation of galectin expression in cells but also for the secretion of multiple members of this protein family, which can be an important novel aspect of unconventional secretion mechanisms.

Design, Synthesis, and Anticancer Activity of a Selenium-Containing Galectin-3 and Galectin-9N Inhibitor.

Galectins are soluble ß-D-galactoside-binding proteins whose implication in cancer progression and disease outcome makes them prominent targets for therapeutic intervention. In this frame, the development of small inhibitors that block selectively the activity of galectins represents an important strategy for cancer therapy which is, however, still relatively underdeveloped. To this end, we designed here a rationally and efficiently novel diglycosylated compound, characterized by a selenoglycoside bond and the presence of a lipophilic benzyl group at both saccharide residues. The relatively high binding affinity of the new compound to the carbohydrate recognition domain of two galectins, galectin 3 and galectin 9, its good antiproliferative and anti-migration activity towards melanoma cells, as well as its anti-angiogenesis properties, pave the way for its further development as an anticancer agent.

Ultrafiltration isolation, structures and anti-tumor potentials of two arabinose- and galactose-rich pectins from leaves of Aralia elata.

Two novel arabinose- and galactose-rich pectic polysaccharides, AELP-B5 (Mw, 4.25 × 104 g/mol) and B6 (Mw, 1.56 × 104 g/mol), were rapidly obtained from the leaves of Aralia elata (Miq.) Seem. with anion resin and sequenced ultrafiltration membrane columns. The structural backbone and branched chains of AELP-B5 and B6 were preliminarily elucidated by mild acid hydrolysis with HILIC-ESI--MS/MS. The planar structures and spatial configurations were further identified using UPLC-QDa and GC-MS for compositions, Smith degradation and methylation analysis, FT-IR, NMR (1H/13C, DEPT, HSQC, HMBC, COSY, NOESY and TOCSY) and SEC-MALLS-RID. (1) AELP-B5 possessed →4GalA1→ as smooth regions (HG) and a repeating disaccharide moiety of →4GalA1→2Rha1→ as hairy regions (RG-I) with a 1:5 molar ratio, whereas AELP-B6 had a distinguishing 1:1 molar ratio between the HG and RG-I; (2) complex side chains were constituted of T-α-Araf, 1,3-α-Araf, 1,5-α-Araf, T-ß-Galp, 1,3-ß-Galp, 1,4-ß-Galp, 1,6-ß-Galp, 1,3,4-ß-Galp and 1,3,4,6-ß-Galp connected at C-4 of the rhamnosyl units in RG-I of AELP-B5 and B6; and (3) both possessed highly branched and compact coil conformations. The CCK-8 assay illustrated that AELP-B6 possessed higher cytotoxicity against HepG2 and HT-29 than that of AELP-B5. Surface plasmon resonance showed the binding affinity of AELP-B6 to galectin-3 (6.488 × 10-5 M) was about 10 times stronger than that of AELP-B5 (4.588 × 10-4 M). The above findings provide a molecular structure and bioactivity basis for future potential applications of AELP in the food and medical industries.

Cowpea polyphenol extract regulates galectin gene expression in bovine blood.

Galectins (GAL) are animal lectins that play important roles in the immune response through regulation of homeostasis and immune function. Bioactive polyphenols are able to bind and regulate galectins in inflammatory diseases. Cowpea is a nutritious and polyphenol-rich legume used as feed. The objective of the study was to evaluate the effect of cowpea polyphenol extract (CPE) on galectin gene transcription and translation in bovine peripheral blood. Blood from lactating cows (n = 10) were treated with CPE (10 µg/mL) or LPS (0.1 µg/mL), and control, to measure mRNA levels of bovine LGALS1, LGALS3, LGALS9, and some innate immune response genes. Secretion of GAL-1, GAL-3 and GAL-9 in plasma were measured using ELISAs. The mRNA expression of LGALS1, LGALS3 and LGALS9 decreased post CPE exposure. CPE decreased plasma GAL-1, but had no effect on GAL-3 and GAL-9. In addition, CPE decreased expression of TNFA, COX2 and upregulated TLR2, IL10 and IL4. LPS stimulation upregulated galectin genes expression and secretion. Overall, cowpea polyphenols modulated galectin expression, particularly GAL 1 in blood. The results provide a springboard for further studies on the use of polyphenol extracts from cowpea enriched feed supplements to target specific galectin genes for improved health and production in dairy cows.

Galectin-Glycan Interactions: Guidelines for Monitoring by 77 Se NMR Spectroscopy, and Solvent (H2 O/D2 O) Impact on Binding.

Functional pairing between cellular glycoconjugates and tissue lectins like galectins has wide (patho)physiological significance. Their study is facilitated by nonhydrolysable derivatives of the natural O-glycans, such as S- and Se-glycosides. The latter enable extensive analyses by specific 77 Se NMR spectroscopy, but still remain underexplored. By using the example of selenodigalactoside (SeDG) and the human galectin-1 and -3, we have evaluated diverse 77 Se NMR detection methods and propose selective 1 H,77 Se heteronuclear Hartmann-Hahn transfer for efficient use in competitive NMR screening against a selenoglycoside spy ligand. By fluorescence anisotropy, circular dichroism, and isothermal titration calorimetry (ITC), we show that the affinity and thermodynamics of SeDG binding by galectins are similar to thiodigalactoside (TDG) and N-acetyllactosamine (LacNAc), confirming that Se substitution has no major impact. ITC data in D2 O versus H2 O are similar for TDG and LacNAc binding by both galectins, but a solvent effect, indicating solvent rearrangement at the binding site, is hinted at for SeDG and clearly observed for LacNAc dimers with extended chain length.

The acid and neutral fractions of pectins isolated from ripe and overripe papayas differentially affect galectin-3 inhibition and colon cancer cell growth.

The water-soluble fractions of pectin extracted from the pulp of ripe papayas have already been found to exert positive effects on cancer cell cultures. However, the mechanisms that lead to these beneficial effects and the pectin characteristics that exert these effects are still not well understood. Characteristics such as molecular size, monosaccharide composition and structural conformation are known as polysaccharide factors that can cause alterations in cellular response. During fruit ripening, a major polysaccharide solubilization, depolymerization, and chemical modification occur. The aims of this work are to fractionate the pectin extracted from the pulp of papayas at two stages of ripening (fourth and ninth day after harvesting) into uronic and neutral fractions and to test them for the inhibition of human recombinant galectin-3 and the inhibition of colon cancer cell growth. The structures of the fractions were chemically characterized, and the uronic fraction extracted from the fourth day after harvesting presented the best biological effects across different concentrations in both galectin-3 inhibition and viability assays. The results obtained may help to establish a relationship between the chemical structures of papaya pectins and the positive in vitro biological effects, such as inhibiting cancer cell growth.

Structure-activity relationship of Citrus segment membrane RG-I pectin against Galectin-3: The galactan is not the only important factor.

Rhamnogalacturonan I (RG-I) pectin are regarded as strong galectin-3 (Gal-3) antagonist because of galactan sidechains. The present study focused on discussing the effects of more structural regions in pectin on the anti-Gal-3 activity. The water-soluble pectin (WSP) recovered from citrus canning processing water was categorized as RG-I pectin. The controlled enzymatic hydrolysis was employed to sequentially remove the α-1,5-arabinan, homogalaturonan and ß-1,4-galactan in WSP. The Gal-3-binding affinity KD (kd/ka) of WSP and debranched pectins were calculated to be 0.32 µM, 0.48 µM, 0.56 µM and 1.93 µM. Moreover, based on the more sensitive cell line (MCF-7) model, the IC30 value of WSP was lower than these of modified pectins, indicating decreased anti-Gal-3 activity. Our results suggested that the total amount of neutral sugar sidechains, the length of arabinan and cooperation between HG and RG-I played important roles in the anti-Gal-3 activity of WSP, not the Gal/Ara ratio or RG-I/HG ratio. These results provided a new insight into structure-activity relationship of citrus segment membrane RG-I as a galectin-3 antagonist and a new functional food.

Galectin-9 Induced by Dietary Prebiotics Regulates Immunomodulation to Reduce Atopic Dermatitis Symptoms in 1-Chloro-2,4-Dinitrobenzene (DNCB)-Treated NC/Nga Mice.

Atopic dermatitis (AD) is a skin disorder that causes chronic itch. We investigated the inhibitory effects of a mixture of prebiotic short-chain galacto-oligosaccharides and long-chain fructooligosaccharides (scGOS/lcFOS), inulin, or ß-glucan on AD development in 1-chloro-2,4- dinitrobenzene (DNCB)-treated NC/Nga mice. Mice were randomly assigned to six groups: untreated mice, AD control, positive control (DNCB-treated NC/Nga mice fed a dietary supplement of Zyrtec), and DNCB-treated NC/Nga mice fed a dietary supplement of prebiotics such as scGOS/lcFOS (T1), inulin (T2), or ß-glucan (T3). The prebiotic treatment groups (T1, T2, and T3) showed suppression of AD symptoms, Th2 cell differentiation, and AD-like skin lesions induced by DNCB. In addition, prebiotic treatment also reduced the number of microorganisms such as Firmicutes, which is associated with AD symptoms, and increased the levels of Bacteroidetes and Ruminococcaceae, which are associated with alleviation of AD symptoms. Our findings demonstrate the inhibitory effects of prebiotics on AD development by improving the Th1/Th2 cytokine balance and beneficial symbiotic microorganisms in in vitro and in vivo models.

Oral Administration of Fucoidan Can Exert Anti-Allergic Activity after Allergen Sensitization by Enhancement of Galectin-9 Secretion in Blood.

A previous study revealed that fucoidan inhibited mast cell degranulation through the upregulation of galectin-9 in blood. The purpose of this study is to elucidate its mechanism using ovalbumin (OVA) induced anaphylaxis model mice (BALB/c, Female, 5-week-old) and mast cell line (RBL-2H3 cells). Oral administration of fucoidan after sensitization with OVA/Al(OH)3 inhibited reduction of rectal temperature induced by activation of mast cells. Fucoidan increased galectin-9 mRNA expression only in colonic epithelial cells. These results suggested that fucoidan could suppress the allergic symptoms in sensitized mice by inducing galectin-9 production from colonic epithelial cells. In addition, to check the influence of galectin 9 on the degranulation of mast cells, RBL-2H3 cell lines were treated directly with recombinant galectin-9. As expected, galectin-9 inhibited degranulation of RBL-2H3 cells pre-bound with IgE. Moreover, the residual amounts of IgE on RBL-2H3 cells were decreased by an addition of galectin-9. It was demonstrated that galectin-9 could remove IgE even if IgE was already bound to mast cells and suppress the mast cells degranulation induced by antigen. This study shows that fucoidan might become an effective therapeutic agent for patients already developed type I allergic diseases.

Rumen-protected methionine supplementation during the peripartal period alters the expression of galectin genes associated with inflammation in peripheral neutrophils and secretion in plasma of Holstein cows.

The work described in this research communication aimed to investigate whether rumen-protected methionine (Met) supplementation during the periparturient period would affect the expression of galectins in blood-derived neutrophils, and secretion of galectins, IL (interleukin)-1ß, IL-6, myeloperoxidase (MPO), and glucose in plasma. Because supplementation of rumen-protected Met would alleviate inflammation and oxidative stress during the peripartal period, we hypothesized that enhancing Met supply would benefit the innate immune response at least in part by altering the expression of galectin genes associated with neutrophil activity and inflammation. Galectins (Gal) have an immuno-modulating effect acting like cell-surface receptors whose activation often results in signaling cascades stimulating cells such as neutrophils. This study revealed an association between Met supplementation and galectin expression and secretion. This implies that galectin expression and secretion can be modulated by Met supplementation. Further studies are needed to evaluate the regulation of galectin gene expression for therapeutic and dietary intervention in the peripartal cow.

Selenoglycosides as Lectin Ligands: 77 Se-Edited CPMG-HSQMBC NMR Spectroscopy To Monitor Biomedically Relevant Interactions.

The fundamental importance of protein-glycan recognition calls for specific and sensitive high-resolution techniques for their detailed analysis. After the introduction of 19 F NMR spectroscopy to study the recognition of fluorinated glycans, a new 77 Se NMR spectroscopy method is presented for complementary studies of selenoglycans with optimised resolution and sensitivity, in which direct NMR spectroscopy detection on 77 Se is replaced by its indirect observation in a 2D 1 H,77 Se HSQMBC spectrum. In contrast to OH/F substitution, O/Se exchange allows the glycosidic bond to be targeted. As an example, selenodigalactoside recognition by three human galectins and a plant toxin is readily indicated by signal attenuation and line broadening in the 2D 1 H,77 Se HSQMBC spectrum, in which CPMG-INEPT long-range transfer ensures maximal detection sensitivity, clean signal phases, and reliable ligand ranking. By monitoring competitive displacement of a selenated spy ligand, the selective 77 Se NMR spectroscopy approach may also be used to screen non-selenated compounds. Finally, 1 H,77 Se CPMG-INEPT transfer allows further NMR sensors of molecular interaction to be combined with the specificity and resolution of 77 Se NMR spectroscopy.

Ginger potentiates the effects of silymarin on liver fibrosis induced by CCL4: the role of galectin-8.

OBJECTIVE: The liver is an important organ that is actively involved in metabolic functions and targeted by a number of toxicants. Galectin-8 (Gal-8) is downregulated in liver fibrosis. Reduced Gal-8 expression correlates with inflammation and metastasis. Therefore, this study aimed to further investigate the benefits of combined administration of silymarin and ginger for CCl4-induced liver injuries in mice. We also investigated the mechanisms underlying the hepatoprotective activity of these herbal drugs and evaluated the role of Gal-8 and apoptosis in liver fibrosis. MATERIALS AND METHODS: Eighty male albino mice were used in this study. Animals were divided into the following groups: control group, fibrotic group, silymarin and ginger group. The CCL4 model was used for the induction of liver fibrosis. RESULTS: Gal-8 expression was reduced in the fibrotic group, while Gal-8 expression was increased in the ginger group and silymarin and ginger group. Tissue levels of nitric oxide (NO) and malondialdehyde (MDA) were markedly increased in the fibrotic group but decreased in the silymarin and ginger group. Additionally, tissue caspase-3 activity and antioxidant markers were decreased in the fibrotic group. However, these markers were increased in the silymarin and ginger group. CONCLUSIONS: Gal-8 is a diagnostic and/or prognostic glycoprotein for liver fibrosis. The combination of silymarin and ginger has protective liver action and reduces the severity and incidence of liver fibrosis.

Galectin-9 Induced by Dietary Probiotic Mixture Regulates Immune Balance to Reduce Atopic Dermatitis Symptoms in Mice.

Probiotics can be an effective treatment for atopic dermatitis (AD), while their mechanism of action is still unclear. Here, we induced AD in mice with 2,4-dinitrochlorobenzene and administrated YK4, a probiotic mixture consisting of Lactobacillus acidophilus CBT LA1, L. plantarum CBT LP3, Bifidobacterium breve CBT BR3, and B. lactis CBT BL3. Then, we have validated the underlying mechanism for the alleviation of AD by YK4 from the intestinal and systematic immunological perspectives. Administration of YK4 in AD mice alleviated the symptoms of AD by suppressing the expression of skin thymic stromal lymphopoietin and serum immunoglobulin E eliciting excessive T-helper (Th) 2 cell-mediated responses. YK4 inhibited Th2 cell population through induce the proportion of Th1 cells in spleen and Treg cells in Peyer's patches and mesenteric lymph node (mLN). CD103+ dendritic cells (DCs) in mLN and the spleen were significantly increased in AD mice administered with YK4 when compared to AD mice. Furthermore, galectin-9 was significantly increased in the gut of AD mice administered with YK4. In vitro experiments were performed using bone marrow-derived DCs (BMDC) and CD4+ T cells to confirm the immune mechanisms of YK4 and galectin-9. The expression of CD44, a receptor of galectin-9, together with programmed death-ligand 1 was significantly upregulated in BMDCs following treatment with YK4. IL-10 and IL-12 were upregulated when BMDCs were treated with YK4. Cytokines together with co-receptors from DCs play a major role in the differentiation and activation of CD4+ T cells. Proliferation of Tregs and Th1 cell activation were enhanced when CD4+T cells were co-cultured with YK4-treated BMDCs. Galectin-9 appeared to contribute at least partially to the proliferation of Tregs. The results further suggested that DCs treated with YK4 induced the differentiation of naïve T cells toward Th1 and Tregs. At the same time, YK4 alleviated AD symptoms by inhibiting Th2 response. Thus, the present study suggested a potential role of YK4 as an effective immunomodulatory agent in AD patients.

Role and translational implication of galectins in arthritis pathophysiology and treatment: A systematic literature review.

Galectins are members of the animal lectin family that bind to the ß-galactoside-containing carbohydrate moieties of glycoconjugates. They seem to have an important role in the pathophysiology of several diseases, including arthritis. Osteoarthritis (OA) and rheumatoid arthritis (RA) are chronic conditions with few or no available therapies. In this context, galectins could provide a novel opportunity, but the precise role and mechanism of their involvement in arthritis are still not fully understood. This descriptive systematic literature review summarizes in vitro, in vivo, and clinical studies that analyzed and examined the role and mechanism of action of galectins in arthritis to highlight and clarify their possible translation implication. This review yielded promising evidence that individual galectins, in particular galectin-1, -3, and -9, could play positive or negative roles in the pathogenesis of arthritis, especially in RA and OA. It also emphasized the cell-dependent role of these galectins. This is particularly true for galectin-1, which was shown to have a protective anti-inflammatory role in RA, while it seemed to be associated with cartilage degeneration in OA. In summary, this review underlined that manipulation of certain galectins can suppress or aggravate disease symptoms in arthritis animal models, demonstrating the therapeutic potential of galectins for the treatment of RA and OA. Nevertheless, despite the fact that galectin therapy and therapies acting on galectin expression seem to be an interesting and important opportunity for research, we highlighted that further investigation is necessary to carefully evaluate their potential clinical implications in arthritis.

Galectin-Carbohydrate Interactions in Biomedicine and Biotechnology.

Cellular communication events are mediated by interactions between cell-surface sugars and lectins, which are carbohydrate-binding proteins. Galectins are ß-galactosyl-binding lectins that bridge molecules by their sugar moieties, forming a signaling and adhesion network. Severe changes in glycosylation and galectin expression accompany major processes in oncogenesis, cardiovascular disorders, and other pathologies, making galectins attractive therapeutic targets. Here we discuss advanced strategies of chemo-enzymatic carbohydrate synthesis for creating lead glycomimetics and (neo-)glycoconjugates for galectin-1 and -3 targeting in biomedicine and biotechnology. We will describe the challenges and bottlenecks on the route into biomedical and biotechnological practice and present the first clinical candidates. The coming era will see an exciting translation of selective well-defined high-affinity galectin ligands from bench to bedside.

Galectin-12 is Involved in Corn Silk-Induced Anti-Adipogenesis and Anti-Obesity Effects.

Obesity is a significant risk factor for various diseases. It is a clinical condition caused by the excessive accumulation of fat, which has a negative impact on human health. Galactin-12 is an adipocyte-expressed protein and possesses adipocyte-inducing activity. We investigated the expression level of candidate proteins involved in galactin-12-mediated adipocyte differentiation pathway. We performed a high-throughput screening assay to monitor galectin-12 promoter activity using 105 traditional Chinese herbs. Corn silk extract and [Formula: see text]-sitosterol reduced the expression of galactin-12 promoter in 3T3-L1 cells. In addition, corn silk extract and [Formula: see text]-sitosterol decreased the level of lipid droplets and downregulated the gene and protein expression level of C/EBP[Formula: see text], C/EBP[Formula: see text], PPAR[Formula: see text], Ap2, and adipsin in 3T3-L1 pre-adipocytes via AKT and ERK1/2 inhibition. In vivo study with the oral administration of corn silk extract and [Formula: see text]-sitosterol in a mouse model showed a significant weight reduction and decrease in adipocytes in several organs such as the liver and adipose tissue. Taken together, corn silk extract and [Formula: see text]-sitosterol may effectively reduce pre-adipocyte differentiation by inhibiting galectin-12 activity and exerting anti-obesity effects. These findings highlight the potential use of corn silk extract and [Formula: see text]-sitosterol as potential candidates for the prevention and treatment of obesity.

Under-Evaluated or Unassessed Pathogenic Pathways in Autoimmune Hepatitis and Implications for Future Management.

Autoimmune hepatitis is a consequence of perturbations in homeostatic mechanisms that maintain self-tolerance but are incompletely understood. The goals of this review are to describe key pathogenic pathways that have been under-evaluated or unassessed in autoimmune hepatitis, describe insights that may shape future therapies, and encourage investigational efforts. The T cell immunoglobulin mucin proteins constitute a family that modulates immune tolerance by limiting the survival of immune effector cells, clearing apoptotic bodies, and expanding the population of granulocytic myeloid-derived suppressor cells. Galectins influence immune cell migration, activation, proliferation, and survival, and T cell exhaustion can be induced and exploited as a possible management strategy. The programmed cell death-1 protein and its ligands comprise an antigen-independent inhibitory axis that can limit the performance of activated T cells by altering their metabolism, and epigenetic changes can silence pro-inflammatory genes or de-repress anti-inflammatory genes that affect disease severity. Changes in the intestinal microbiota and permeability of the intestinal mucosal barrier can be causative or consequential events that affect the occurrence and phenotype of immune-mediated disease, and they may help explain the female propensity for autoimmune hepatitis. Perturbations within these homeostatic mechanisms have been implicated in experimental models and limited clinical experiences, and they have been favorably manipulated by monoclonal antibodies, recombinant molecules, pharmacological agents or dietary supplements. In conclusion, pathogenic mechanisms that have been implicated in other systemic immune-mediated and liver diseases but under-evaluated or unassessed in autoimmune hepatitis warrant consideration and rigorous evaluation.

Unconventional secretion of annexins and galectins.

Eukaryotic cells have a highly evolved system of protein secretion, and dysfunction in this pathway is associated with many diseases including cancer, infection, metabolic disease and neurological disorders. Most proteins are secreted using the conventional endoplasmic reticulum (ER)/Golgi network and as such, this pathway is well-characterised. However, several cytosolic proteins have now been documented as secreted by unconventional transport pathways. This review focuses on two of these proteins families: annexins and galectins. The extracellular functions of these proteins are well documented, as are associations of their perturbed secretion with several diseases. However, the mechanisms and regulation of their secretion remain poorly characterised, and are discussed in this review. This review is part of a Special Issues of SCDB on 'unconventional protein secretion' edited by Walter Nickel and Catherine Rabouille.

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 ß-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.