Circulating galectin-1 delineates response to bevacizumab in melanoma patients and reprograms endothelial cell biology.

Blockade of vascular endothelial growth factor (VEGF) signaling with bevacizumab, a humanized anti-VEGF monoclonal antibody (mAb), or with receptor tyrosine kinase inhibitors, has improved progression-free survival and, in some indications, overall survival across several types of cancers by interrupting tumor angiogenesis. However, the clinical benefit conferred by these therapies is variable, and tumors from treated patients eventually reinitiate growth. Previously we demonstrated, in mouse tumor models, that galectin-1 (Gal1), an endogenous glycan-binding protein, preserves angiogenesis in anti-VEGF-resistant tumors by co-opting the VEGF receptor (VEGFR)2 signaling pathway in the absence of VEGF. However, the relevance of these findings in clinical settings is uncertain. Here, we explored, in a cohort of melanoma patients from AVAST-M, a multicenter, open-label, randomized controlled phase 3 trial of adjuvant bevacizumab versus standard surveillance, the role of circulating plasma Gal1 as part of a compensatory mechanism that orchestrates endothelial cell programs in bevacizumab-treated melanoma patients. We found that increasing Gal1 levels over time in patients in the bevacizumab arm, but not in the observation arm, significantly increased their risks of recurrence and death. Remarkably, plasma Gal1 was functionally active as it was able to reprogram endothelial cell biology, promoting migration, tubulogenesis, and VEGFR2 phosphorylation. These effects were prevented by blockade of Gal1 using a newly developed fully human anti-Gal1 neutralizing mAb. Thus, using samples from a large-scale clinical trial from stage II and III melanoma patients, we validated the clinical relevance of Gal1 as a potential mechanism of resistance to bevacizumab treatment.

[A functional platform to monitor SARS-CoV-2-specific T cell responses in vaccinated individuals and COVID-19 recovered patients]. / COVID-T: Una plataforma funcional para monitorear la respuesta de linfocitos T específicos de SARS-CoV-2 en individuos vacunados y recuperados de COVID-19.

The rapid spread of the SARS-CoV-2, the causative agent of the emergent pandemic disease COVID-19, requires the urgent commitment of the immunology community to understand the adaptive immune response developed by COVID-19 convalescent patients and individuals vaccinated with different strategies and schemes, with the ultimate goal of implementing and optimizing health care and prevention policies. Currently, assessment of SARS-CoV-2-specific immunity is mainly focused on the measurement of the antibody titers and analysis of their neutralizing capacity. However, a considerable proportion of individuals lack humoral responses or show a progressive decline of SARS-CoV-2-specific neutralizing antibodies. In order to study the cellular response of convalescent patients and vaccinated individuals, we have developed the "COVID-T Platform", an optimized strategy to study SARS-CoV-2-specific T cell responses. This platform allows assessment of the nature, magnitude and persistence of antigen-specific T-cell immunity in COVID-19-convalescent patients and vaccinated individuals. Moreover, it gives the opportunity to study cellular responses against emerging coronavirus variants and to identify individuals with cross-reactive immunity against seasonal coronaviruses.

La rápida propagación del coronavirus SARS-CoV-2, agente causal de la enfermedad pandémica emergente COVID-19 y sus nuevas variantes, requiere del compromiso de la comunidad inmunológica para comprender la magnitud y naturaleza de la respuesta inmunológica adaptativa desarrollada por pacientes recuperados de COVID-19 e individuos vacunados con diferentes estrategias y protocolos, a los fines de implementar nuevas políticas sanitarias. En la actualidad, la determinación de la inmunidad contra SARS-CoV-2 se basa principalmente en la detección de anticuerpos específicos y la determinación de su actividad neutralizante. Sin embargo, a pesar de la alta sensibilidad de estos ensayos, un número considerable de pacientes e individuos vacunados carecen de respuesta humoral detectable, o evidencian una disminución rápida de la misma en el tiempo. Con el objetivo de estudiar la respuesta inmune celular desencadenada frente a SARS-CoV-2, en nuestro laboratorio desarrollamos la "Plataforma COVID-T" estrategia integral optimizada dirigida a caracterizar y monitorear la respuesta de linfocitos T específicos de SARS-CoV-2 a partir de muestras de sangre de individuos vacunados y/o recuperados de COVID-19. Esta plataforma permite evaluar la naturaleza, magnitud y persistencia de la inmunidad celular T generada tanto por la infección con SARS-CoV-2, como por distintos esquemas y protocolos de vacunación en diferentes poblaciones de individuos. Asimismo, permite evaluar la respuesta inmunológica T generada frente a nuevas variantes del virus e identificar individuos sanos resistentes a SARS-CoV-2 con inmunidad pre-existente hacia coronavirus estacionales.

COVID-T: una plataforma funcional para monitorear la respuesta de linfocitos t específicos de SARS-COV-2 en individuos vacunados y recuperados de COVID-19 / COVID-T: A functional platform to monitor SARS-CoV-2-specific T cell responses in vaccinated individuals and COVID-19 recovered patients

Resumen La rápida propagación del coronavirus SARS-CoV-2, agente causal de la enfermedad pandémica emergente COVID-19 y sus nuevas variantes, requiere del compromiso de la comunidad inmunológica para comprender la magnitud y naturaleza de la respuesta inmunológica adaptativa desarrollada por pacientes recuperados de COVID-19 e individuos vacunados con diferentes estrategias y protocolos, a los fines de imple mentar nuevas políticas sanitarias. En la actualidad, la determinación de la inmunidad contra SARS-CoV-2 se basa principalmente en la detección de anticuerpos específicos y la determinación de su actividad neutralizante. Sin embargo, a pesar de la alta sensibilidad de estos ensayos, un número considerable de pacientes e indivi duos vacunados carecen de respuesta humoral detectable, o evidencian una disminución rápida de la misma en el tiempo. Con el objetivo de estudiar la respuesta inmune celular desencadenada frente a SARS-CoV-2, en nuestro laboratorio desarrollamos la "Plataforma COVID-T" estrategia integral optimizada dirigida a caracte rizar y monitorear la respuesta de linfocitos T específicos de SARS-CoV-2 a partir de muestras de sangre de individuos vacunados y/o recuperados de COVID-19. Esta plataforma permite evaluar la naturaleza, magnitud y persistencia de la inmunidad celular T generada tanto por la infección con SARS-CoV-2, como por distintos esquemas y protocolos de vacunación en diferentes poblaciones de individuos. Asimismo, permite evaluar la respuesta inmunológica T generada frente a nuevas variantes del virus e identificar individuos sanos resistentes a SARS-CoV-2 con inmunidad pre-existente hacia coronavirus estacionales.

Abstract The rapid spread of the SARS-CoV-2, the caus ative agent of the emergent pandemic disease COVID-19, requires the urgent commitment of the immunology community to understand the adaptive immune response developed by COVID-19 convalescent patients and individuals vaccinated with different strategies and schemes, with the ultimate goal of implementing and optimizing health care and prevention policies. Currently, assessment of SARS-CoV-2-specific immunity is mainly focused on the measurement of the antibody titers and analysis of their neutralizing capacity. However, a considerable proportion of individuals lack humoral responses or show a progressive decline of SARS-CoV-2-specific neutral izing antibodies. In order to study the cellular response of convalescent patients and vaccinated individuals, we have developed the 'COVID-T Platform', an optimized strategy to study SARS-CoV-2-specific T cell responses. This platform allows assessment of the nature, magnitude and persistence of antigen-specific T-cell immunity in COVID-19-convalescent patients and vaccinated individuals. Moreover, it gives the opportunity to study cellular responses against emerging coronavirus variants and to identify individuals with cross-reactive immunity against seasonal coronaviruses.

Circulating Galectin-1 and Galectin-3 in Sera From Patients With Systemic Sclerosis: Associations With Clinical Features and Treatment.

Systemic Sclerosis (SSc) is a rheumatic disease characterized by fibrosis, microvascular damage and immune dysregulation. Two major subsets, limited cutaneous systemic sclerosis (lcSSc) and diffuse cutaneous systemic sclerosis (dcSSc) can be defined, according to the extent of skin involvement. Increasing evidence indicates a role for galectins in immune and vascular programs, extracellular matrix remodeling and fibrosis, suggesting their possible involvement in SSc. Here, we determined serum levels of galectin (Gal)-1 and Gal-3 in 83 SSc patients (dcSSc n = 17; lcSSc n = 64; ssSSc n = 2), and evaluated their association with clinical manifestations of the disease. Patients with dcSSc showed lower Gal-3 levels, compared to lcSSc (p = 0.003), whereas no considerable difference in Gal-1 levels was detected between groups. Remarkably, higher concentrations of Gal-1 were associated with the presence of telangiectasias (p = 0.015), and higher concentrations Gal-3 were associated with telangiectasias (p = 0.021), diarrhea (p = 0.039) and constipation (p = 0.038). Moreover, lower Gal-3 levels were associated with the presence of tendinous retractions (p = 0.005). Patients receiving calcium blockers (p = 0.048), methotrexate (p = 0.046) or any immunosuppressive treatment (p = 0.044) presented lower concentrations of Gal-3 compared to those not receiving such treatments. The presence of telangiectasia and the type of SSc maintained their statistical association with Gal-3 (ß 0.25; p = 0.022 and ß 0.26; p = 0.017, respectively) in multiple linear regression models. In conclusion, serum levels of Gal-3 are associated with clinical manifestations of SSc. Among them, the presence of telangiectasias could be explained by the central role of this lectin in the vascularization programs.

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

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

Clinical Relevance of Galectin-1 and Galectin-3 in Rheumatoid Arthritis Patients: Differential Regulation and Correlation With Disease Activity.

Galectins, a family of animal lectins, play central roles in immune system regulation, shaping both innate and adaptive responses in physiological and pathological processes. These include rheumatoid arthritis (RA), a chronic multifactorial autoimmune disease characterized by inflammatory responses that affects both articular and extra-articular tissues. Galectins have been reported to play central roles in RA and its experimental animal models. In this perspective article we present new data highlighting the regulated expression of galectin-1 (Gal-1) and galectin-3 (Gal-3) in sera from RA patients under disease-modifying anti-rheumatic drugs (DMARDs) and/or corticoid treatment in the context of a more comprehensive discussion that summarizes the roles of galectins in joint inflammation. We found that Gal-1 levels markedly increase in sera from RA patients and positively correlate with erythrocyte sedimentation rate (ERS) and disease activity score 28 (DAS-28) parameters. On the other hand, Gal-3 is downregulated in RA patients, but positively correlates with health assessment questionnaire parameter (HAQ). Finally, by generating receiver-operator characteristic (ROC) curves, we found that Gal-1 and Gal-3 serum levels constitute good parameters to discriminate patients with RA from healthy individuals. Our findings uncover a differential regulation of Gal-1 and Gal-3 which might contribute to the anti-inflammatory effects elicited by DMARDs and corticoid treatment in RA patients.

Glyco-nano-oncology: Novel therapeutic opportunities by combining small and sweet.

Recent efforts toward defining the molecular features of the tumor microenvironment have revealed dramatic changes in the expression of glycan-related genes including glycosyltransferases and glycosidases. These changes affect glycosylation of proteins and lipids not only in cancer cells themselves, but also in cancer associated-stromal, endothelial and immune cells. These glycan alterations including increased frequency of ß1,6-branched N-glycans and bisecting N-glycans, overexpression of tumor-associated mucins, preferred expression of T, Tn and sialyl-Tn antigen and altered surface sialylation, may contribute to tumor progression by masking or unmasking specific ligands for endogenous lectins, including members of the C-type lectin, siglec and galectin families. Differential expression of glycans or glycan-binding proteins could be capitalized for the identification of novel biomarkers and might provide novel opportunities for therapeutic intervention. This review focuses on the biological relevance of lectin-glycan interactions in the tumor microenvironment (mainly illustrated by the immunosuppressive and pro-angiogenic activities of galectin-1) and the design of functionalized nanoparticles for pharmacological delivery of multimeric glycans, lectins or selective inhibitors of lectin-glycan interactions with antitumor activity.

Effects of polyamines on the release of gonadotropin-releasing hormone and gonadotropins in developing female rats.

Polyamines, putrescine (PUT), spermidine (SPD), spermine (SPM), and agmatine (AGM), are polycationic amines related to multiple cell functions found in high concentrations during the development of hypothalamus and pituitary. In previous works, we demonstrated that alpha-difluoromethylornithine (DFMO), an inhibitor of polyamines biosynthesis, induced a delay in puberty of female rats, accompanied by high, sustained follicle-stimulating hormone (FSH) levels during the infantile period. Also, DFMO treatment induced changes in polyamine concentration both in hypothalamus and pituitary of rats, mainly a decrease of PUT and SPD, an increase in SPM, and no change in AGM. In the present work, we investigated the direct effects of polyamines on the secretion of hypothalamic GnRH and pituitary gonadotropins in 6- and 15-day-old female rats. In 6-day-old animals, in vitro incubations with PUT, SPD, and AGM of hypothalami or anterior pituitaries were able to inhibit GnRH, FSH, and leutinizing hormone (LH) secretion, respectively. SPM showed a nonspecific transient inhibitory effect on FSH. When challenged with either high K(+) (hypothami) or GnRH (pituitaries), the tissues incubated in the presence of polyamines showed no differences when compared with their controls. No effects of polyamines in 15-day-old rats in either tissue were observed. Pituitary cell cultures of 6-day-old animals incubated with DFMO for 4 days showed a significant increase in FSH, but not in LH. We conclude that high PUT, SPD, and AGM levels during the first 10 days of life are important for the development of the hypothalamic-hypophyseal unit, probably related to an inhibitory effect on GnRH and gonadotropins. Therefore, polyamine participation, especially PUT and SPD, is of importance in the regulation of GnRH and gonadotropin secretion in the neonatal and infantile periods, critical stages in the establishment of sexual differentiation.