Biology subjects

Cabral, M. G.

Publications and source records attributed to Cabral, M. G..

6 recordsLinked to original sources

bioRxiv2026

CCR4+low-density neutrophils define a novel immunosuppressive subset associated with breast cancer progression and early mortality

Neutrophils are increasingly recognized as key players in cancer progression, yet their functional heterogeneity limits their therapeutic exploitation. In breast cancer (BC), elevated circulating and tumor-associated neutrophils have been associated with poor prognosis, and low-density neutrophils (LDN), particularly, have been linked to immunosuppression. However, the specific neutrophil subsets driving these effects remain undefined. Here, we identify a previously unrecognized CCR4-expressing neutrophil subset, strongly enriched among LDN, whose frequency rises with disease stage and correlates with faster progression and shorter survival. Serial blood sampling further showed that CCR4+LDN levels fluctuate in line with clinical course, with increases indicating near-term risk in metastatic patients. Our findings also reveal that this subset has an immunosuppressive signature more pronounced than that of the remaining LDN, migrates preferentially toward tumor-derived chemokines, and dampens T cell-driven tumor killing even when PD-1 is blocked. Additionally, in a pilot cohort of Triple-Negative BC patients on anti-PD-1 therapy, early changes in this population were associated with treatment outcome. Together, these results reveal a distinct neutrophil population that actively contributes to immune escape and tumor progression, establishing CCR4+LDN as a minimally invasive real-time biomarker of disease course and treatment response, and as a promising target for neutrophil-directed therapies in BC.

immunology↗

bioRxiv2026

Genomic Epidemiology of Canine Distemper Virus (CDV) in Neotropical Primates in Brazil Reveals Multiple Spillover Events and Convergent Evolution at Hemagglutinin Residue 519

Canine distemper virus (CDV; Morbillivirus canis) is a multi-host paramyxovirus primarily maintained in the order Carnivora. However, recent outbreaks in Neotropical primates suggest recurrent cross-species spillover into non-human primates. Between May and July 2022, seven marmosets (Callithrix penicillata) were found dead in urban and peri-urban areas of Montes Claros, Minas Gerais, Brazil. Viral metagenomic sequencing recovered two near complete CDV genomes directly from liver samples. Maximum likelihood and Bayesian phylogenetic analyses placed these genomes within the South American CDV lineage and supported at least three independent zoonotic introductions into Callithrix populations. Domestic dogs (Canis lupus familiaris) were inferred as the most likely source and the crab-eating fox (Cerdocyon thous) as a probable bridge host. Ancestral-state reconstruction identified a substitution at position 519 of the hemagglutinin (H) protein (R519I in the two primate clades and R519G in a singleton primate sequence). In silico modelling of the marmoset signaling lymphocytic activation molecule (SLAM) complex was consistent with a modest reorganisation of the receptor-binding head in the 519-substituted variants (ipTM = 0.82), generating a testable hypothesis that this residue may contribute to adaptation at the primate SLAM receptor interface and is associated with altered predicted docking orientation for the receptor. Together, these findings suggest that residue 519 is a candidate marker of CDV adaptation to Neotropical primates and emphasise the importance of integrating genomic surveillance with domestic dog vaccination efforts under a One Health framework to reduce the threat of CDV spillover to vulnerable wildlife populations.

genomics↗

bioRxiv2025

Neutrophils matter: New clinical insights on their role in the progression of metastatic breast cancer

BackgroundMetastatic breast cancer (BC) remains a significant clinical challenge, needing innovative strategies to improve disease management and extend patient survival. Increased neutrophil levels have been observed in both peripheral blood and tumor tissues of patients with different types of cancer, often being associated with poor clinical outcomes. These findings suggest a crucial role for neutrophils in tumor progression, raising interest in neutrophil-based therapies. However, the functional and phenotypic heterogeneity of neutrophils complicates their therapeutic targeting. This study aims to investigate the clinical impact of immunosuppressive, protumor low-density neutrophils (LDN) in metastatic BC, comparing them with normal high-density neutrophils (HDN) to better understand their role in disease progression. MethodsLDN and HDN subpopulations were isolated from the blood of 151 BC patients (72 metastatic, 79 non-metastatic) using density gradient centrifugation. Their frequency, phenotype, and function were analyzed by flow cytometry and in vitro experiments. Correlations between LDN levels and clinical data from metastatic BC patients were evaluated, alongside individual longitudinal assessments. ResultsLDN accumulated significantly in the blood of BC patients, particularly in those with metastatic disease. Elevated LDN levels in these patients were associated with faster disease progression and reduced life expectancy, regardless of metastatic site. Longitudinal analysis revealed that higher LDN percentages often correlated with adverse clinical events, whereas lower levels of LDN were linked to stable disease. Functionally, LDN exhibited protumor properties, including elevated expressions of PD-L1 and MMP-9, contributing to immunosuppression and metastasis. Unlike HDN, which demonstrated cytotoxicity against tumor cells, LDN failed to reduce BC cell line viability in 3D co-cultures. Notably, BC cell lines exposed to LDN-conditioned medium showed increased invasive capacity and proliferation, while T cells cultured in the same medium displayed impaired activation, likely due to the effect of arginase. ConclusionOur results highlighted LDN and their secreted factors as major drivers of BC progression and increased aggressiveness. These findings suggest that incorporating LDN assessment into clinical practice could aid in identifying high-risk patients and enable more personalized treatment approaches. Furthermore, our data strengthen the relevance of targeting specific neutrophil subsets or their functions to improve metastatic BC management and patient outcomes.

immunology↗

bioRxiv2021

Determination of HLA-DR level in cytotoxic T lymphocytes: a new validated tool to predict breast cancer response to treatment

BackgroundNeoadjuvant chemotherapy (NACT) is the usual treatment for locally-advanced breast cancer (BC). However, more than half of the patients lack an effective response to this treatment. Thus, its urgent to find predictive biomarkers. Recently, we proposed the HLA-DR expression level in cytotoxic T lymphocytes (CTLs) as a robust biomarker to select, in advance, patients that will actually benefit from NACT. Patients and MethodsA total of 202 BC patients, 102 of which submitted to NACT, were enrolled in this study. 61 biopsies and 41 blood samples collected pre-NACT and 100 non-NACT tumor samples were immunophenotyped by flow cytometry. Both NACT and non-NACT patients were followed up for 34 months. Blood-isolated immune cells were cultured with BC cell lines in a 3D system. ResultsHere we confirmed that HLA-DR level in CTLs is a highly sensitive and specific biomarker to predict BC response to NACT, reflected in circulation and independent of the patients age, BC subtype and other tumor-immunological features. Therefore, we developed a predictive probability model, based on the determination of HLA-DR level in tumor-infiltrating CTLs, that could be used to guide therapeutic decisions. Interestingly, this biomarker was also associated with progression-free survival, regardless the treatment. Contrary to HLA-DRnegative CTLs, HLA-DR+ CTLs were able to reduce the viability of tumor cells, in culture, in agreement with their higher expression of activation, proliferation and cytotoxicity-related molecules. Tissue-residency and memory markers were also increased in HLA-DR+ CTLs. These anti-tumor features of HLA-DR+ CTLs may justify the clinical observations. ConclusionHLA-DR level in CTLs is a validated and independent biomarker to predict response to NACT which allow the establishment of a clinical meaningful tool to select in advance patients that will truly benefit from this treatment. Intriguingly, it may be further used as a biomarker of BC patients general prognosis. Highlights- HLA-DR level in cytotoxic T cells is an independent predictive factor of breast cancer response to NACT - A predictive probability model based on this biomarker was developed as a new tool to improve treatment decisions - HLA-DR level in cytotoxic T cells is also reflected systemically - HLA-DR level in cytotoxic T cells is also a prognostic factor, associated with progression-free survival - HLA-DR+ cytotoxic T cells exhibit several phenotypic and functional anti-tumor characteristics

immunology↗

bioRxiv2021

Circulating Low Density Neutrophils of Breast Cancer Patients are Associated with their Worse Prognosis due to the Impairment of T cell Responses

Neutrophils are prominent immune components of solid tumors, which can protect against the onset of cancer (N1) or have pro-tumor activity (N2). Circulating neutrophils, divided into high density neutrophils (HDN) and low density neutrophils (LDN), functionally mirror those N1 and N2 cells, respectively. LDN, a rare subset in non-pathological conditions, have been extensively studied in cancer, due to their frequency in this disease and their pro-tumor phenotype. However, this has been mainly demonstrated in animal models and proper validation in humans is an urgent need. Here, we further enlighten the clinical impact of LDN in a cohort of breast cancer (BC) patients. We observed that LDN were practically absent in healthy donors blood, while were significantly increased in the blood of BC patients, particularly with metastatic disease. Relevant for a clinical translation, within the population of non-metastatic patients, LDN were more prevalent in patients with poor response to neoadjuvant chemotherapy than in responders. The association of a higher incidence of circulating LDN and the worse prognosis of BC patients could be explained by the pro-tumor/immunosuppressive characteristics exhibited by these cells. Namely, there are more LDN expressing the immunosuppressive marker PD-L1, than HDN. Additionally, LDN also showed increased expression of activation markers; a robust formation of neutrophil extracellular traps; an augmented phagocytic activity; and a higher capacity to release reactive oxygen species, which may contribute for tumor development and metastization. Moreover, the percentage of LDN in BC patients blood was negatively correlated with activated cytotoxic T lymphocytes and positively correlated with the immunosuppressive CCR4+ regulatory T cells, corroborating their impairment on the anti-tumor immune responses, which was further demonstrated ex vivo. Hence, this study reveals the potential of LDN as a clinical meaningful biomarker of BC response to treatment and opens new avenues for developing targeted immunotherapies.

immunology↗

bioRxiv2020

Differential expression between African-ancestry and White patients diagnosed with Triple-Negative Breast Cancer: EGFR, Myc, Bcl2 and β-Catenin as ancestry-associated markers

PurposeTriple-negative breast cancer (TNBC) has a higher incidence, a younger age of onset, and a more aggressive behavior in African-ancestry women. Biological disparities have been suggested as an important factor influencing the ancestry-associated TNBC discrepancy. In this study, we sought to identify ancestry-associated differential gene and protein expression between African-ancestry and White TNBC patients, controlling for patients menopause status and pathological staging at diagnosis. MethodsDifferential gene expression analyses (DGEA) were performed using RNA-sequencing data from The Cancer Genome Atlas (TCGA). Gene set enrichment analysis (GSEA) and Ingenuity Pathway Analysis (IPA), with focus on network design, were performed to highlight candidate genes for further validation through immunohistochemistry of TNBC samples from patients followed in Portugal. ResultsWith 52 African-American and 90 White TNBC patients included, TCGAs data corroborate that African-American patients have a higher TNBC incidence (28.42% vs 11.89%, p<0.0001). Particularly, premenopausal and stage II disease African-American patients also have significantly lower survival probability, comparing with White patients (log-rank p=0.019 and 0.0038, respectively). DGEA results suggest that expression profile differences are more associated with TNBC staging than with patients menopause status. Hippo pathway and cellular community gene sets are downregulated, while breast cancer gene set is upregulated in African-Americans, comparing with White TNBC patients. Furthermore, MAPK pathway gene set is upregulated when controlling for stage II disease. Due to their central role in highly scored networks resulted from IPAs network design, EGFR, Myc and Bcl2 genes were selected for further validation through immunohistochemistry. We also included {beta}-Catenin in the validation study as it is consensually reported to be required in TNBC tumorigenesis. Although patients used in the DGEA and in the immunohistochemistry experiments are geographically and culturally distinct, both groups of African-ancestry patients are mostly of western-African ancestry and, interesting, differential gene and protein expression matched. ConclusionsWe found ancestry-associated gene expression patterns between African-ancestry and White TNBCs, particularly when controlling for menopause status or staging. EGFR, Myc, Bcl2 and {beta}-catenin gene and protein differential expression matching results in distinct populations suggest these markers as being important indicators of TNBCs ancestry-associated development.

cancer biology↗