Biology subjects

Munoz, J.

Publications and source records attributed to Munoz, J..

At least 19 recordsLinked to original sources

bioRxiv2026

Harnessing Vitis germplasm diversity to dissect and predict adventitious rooting traits in grapevine

Adventitious root formation (ARF) is a critical trait for the cost-effective propagation of grapevines in commercial nurseries. Poor rooting ability can limit the use and adoption of new rootstocks derived from underutilized Vitis species, constraining breeding efforts largely to the traditional trio: Vitis riparia, V. rupestris, and V. berlandieri. Despite its agronomic relevance, the genetic basis of ARF remains poorly characterized across the broader Vitis genus. In this study, we evaluated 308 accessions representing 18 Vitis species over three growing seasons, quantifying rooting performance at two developmental stages, callus-stage and post-transplant, alongside root biomass, cutting weight, and a derived transplant-response index. We observed extensive phenotypic variation both within and across species, and species rankings depended on the trait considered. V. riparia, V. rupestris and V. californica ranked among the top five species for all four rooting traits, whereas V. cinerea and V. candicans ranked among the lowest for root weight and post-transplant rooting. V. arizonica and V. acerifolia rooted well at the callus stage but were intermediate after transplanting, and V. berlandieri was among the weakest at the callus stage yet intermediate for post-transplant rooting. Repeatability was moderate to high for root weight (0.74) and callus-stage rooting (0.66), and lower for post-transplant rooting (0.47), reflecting both genetic control and season-to-season variation. Between-species differences accounted for 68% of the genetic variance in callus-stage rooting but only 10% in cutting weight. Rooting was associated with the climate of each accession's wild site of origin: after removing differences among species, accessions originating from sites with lower dry-season precipitation rooted better and produced more root biomass. Genome-wide association analysis using 3.4 million SNPs identified 54 significant SNPs resolving into 18 independent loci across four traits, with root weight contributing 12 of them. Candidate genes in linkage with these loci include a mitogen-activated protein kinase, a SCARECROW-LIKE GRAS transcription factor, PASTICCINO1, expansin A1, an AP2/ERF-RAV1 transcription factor, a tandem array of caffeoyl-CoA O-methyltransferases, and several sugar, peptide and nitrate transporters, implicating auxin-linked cell proliferation, cell wall and lignin remodeling, and solute transport. Genomic and phenomic prediction models yielded moderate accuracies across traits and seasons; up to r = 0.67 for post-transplant rooting within a season and r = 0.65 for previously unevaluated accessions. Moreover, the integration of spectral and genotypic data further improved predictive performance. Prediction accuracy was essentially flat between 5,000 and 50,000 markers. This study establishes a foundational framework for the genetic improvement of grapevine rootstocks, promoting broader use of resilient, high-performing, and clonally-propagable germplasm in viticulture.

genetics↗

bioRxiv2026

GATA4 loss promotes mutant Kras-driven pancreatic ductal adenocarcinoma in the absence of canonical precursor lesions

ABSTRACTGATA6 and GATA4 play key roles in pancreatic development and are essential to maintain the classical transcriptional program in pancreatic ductal adenocarcinoma (PDAC). Using genetic mouse models we show that, in contrast to GATA6, GATA4 is dispensable for the maintenance of acinar homeostasis in the adult pancreas. Deletion of Gata4 in mice expressing mutant Kras in the embryonic pancreas (KG4C) leads to PDAC development in the absence of tissue remodeling, pancreatic intraepithelial neoplasia (PanIN), or other canonical precursor lesions present in Gata4-proficient (KC) mice. Similar observations were made when Gata4 was selectively inactivated in adult, Kras-mutant, acinar cells. We identify Pale Acinar Lesions (PALes) as a previously unrecognized pancreatic lesion, distinct from acino-ductal metaplasia (ADM) and PanINs, present in KC and KG4C mice but not in wild type mice. PALes display weak expression of acinar and ductal markers and lack mucins; they have lower proliferation rates than PanINs. RNA-seq and ChIP-seq reveal that GATA4 and GATA6 partially share genomic binding sites and transcriptomic effects, but they exert opposing influences on mutant Kras-induced, haematopoietic cell-dependent, transcriptional inflammatory programs. Adenoviral-mediated pancreatic expression of IL17 restored the formation of ductal lesions in KG4C mice but failed to rescue PanIN development. Our data indicate that GATA4 functions through the coordinated action of multiple inflammatory factors that are required for ADM/PanIN formation but are dispensable for PDAC development. Collectively, these findings challenge current paradigms of PDAC initiation and progression.

cancer biology↗

bioRxiv2026

A novel Flavobacterium quisquiliarum porphyrin binding protein independently disrupts Pseudomonas aeruginosa biofilms

Bacterial biofilms underpin chronic infection and antimicrobial resistance, notably in Pseudomonas aeruginosa. Here we deconvolute a commercial alginate lyase preparation from Flavobacterium quisquiliarum and identify a previously uncharacterised [~]21 kDa porphyrin-binding protein (FqPBP). Structural, biophysical and docking analyses reveal high-affinity tetrapyrrole binding. Recombinant FqPBP independently inhibits and disperses P. aeruginosa biofilms, implicating porphyrin sequestration and iron homeostasis in biofilm control and highlighting a potential therapeutic strategy targeting iron acquisition pathways.

microbiology↗

bioRxiv2026

Extracellular Vesicles from Senescent Tumor Cells Are Necessary and Sufficient to Drive Paracrine Senescence

Cellular senescence exerts powerful non-cell autonomous effects through the senescencelzlassociated secretory phenotype (SASP). This SASP comprises soluble factors and extracellular vesicles (EVs). Although soluble SASP components can induce senescence in neigbouring cells, the specific contribution of EVs to paracrine senescence is poorly defined. Here, we show that EVs released by senescent tumor cells are necessary and sufficient to propagate senescence. Conditioned media from bleomycinlzlinduced senescent A549 cells triggered a permanent growth arrest with morphological changes and upregulation of senescence markers in recipient tumor cells. Pharmacological inhibition of EV biogenesis using GW4869 or genetic downregulation of the EV secretion mediator RAB27A markedly attenuates paracrine senescence without affecting soluble SASP factor secretion or the senescent state of producer cells. Proteomic characterization reveals that senescent EVs exhibit a distinct molecular signature enriched for extracellular components and processes related to wound healing and hemostasis. Importantly, purified senescent EVs, devoid of soluble SASP factors, fully recapitulated paracrine senescence induction. These findings identify senescent EVs as key autonomous SASP effectors and highlight vesicular pathways as potential therapeutic targets in cancer and therapylzlinduced senescence.

cancer biology↗

bioRxiv2025

Leveraging foundation models to dissect the genetic basis of cluster compactness and yield in grapevine

Grape cluster compactness is a key trait that influence fruit quality, yield, and disease susceptibility. Understanding the genetic basis of this trait is essential for optimizing vineyard management and improving grapevine cultivars. In this study, we performed quantitative trait locus (QTL) mapping to identify genomic regions associated with cluster architecture and yield components in a bi-parental population derived from Vitis vinifera cv. Riesling x Cabernet Sauvignon. A total of 138 full-sibling progeny were evaluated over two growing seasons at Oakville, Napa Valley, California. Traditional yield-related traits were measured, including cluster number, total cluster weight, and average cluster weight. Additionally, an image-based phenotyping pipeline leveraging the foundation model Segment Anything Model (SAM) was employed to segment individual berries, measure their size and shape, and compute cluster compactness with minimal manual intervention. Trait correlations revealed that compact clusters tended to have a higher berry count but smaller berry size, highlighting the role of compactness in modulating cluster structure. Heritability estimates varied across traits, with berry dimensions and compactness displaying moderate to high heritability, indicating strong genetic control. Two parental linkage maps were constructed using a pseudo-test cross strategy. QTL mapping identified multiple loci associated with cluster architecture and yield components, with several stable QTLs detected across both years. Notably, a QTL for cluster compactness was found in both seasons on chromosome 1 in Cabernet Sauvignon. Other stable QTLs were associated with berry size (chromosomes 6 and 17) and berry count (chromosome 5 in Cabernet Sauvignon and chromosome 7 in Riesling). Additional QTLs were detected in a single year, reflecting the influence of environmental variation. Our findings provide valuable insights into the application of foundation models requiring no prior training and minimal intervention for high-quality segmentation and enhance our understanding of the genetic architecture of cluster compactness and yield traits. The genomic regions identified in this study offer promising targets for breeding programs aimed at improving grape quality and disease resistance.

genetics↗

bioRxiv2025

Hyperspectral Sensing for High-Throughput Screening of Boron Tolerance in Grapevines

Boron (B) is an essential micronutrient for grapevine growth, yet excessive levels can impair photosynthesis, reduce yields, and diminish fruit quality. In this study, we evaluated the potential of hyperspectral radiometry combined with machine learning to identify B-tolerant rootstocks rapidly and cost-effectively. We screened both commercial grapevine rootstocks and wild Vitis germplasm under B treatments ranging from 0.5 to 8 ppm, measuring leaf B accumulation, stomatal conductance, photosystem II efficiency, and leaf reflectance (R380-R1100 nm). Our results revealed substantial genotypic variation in B exclusion, with some genotypes maintaining low leaf B content despite high external concentrations. Classification models (Partial Least Squares Discriminant Analysis and Random Forest classification) outperformed regression models (Partial Least Squares Regression and Random Forest regression) in distinguishing B-excluding genotypes, achieving moderate to high accuracy within just eight days after stress initiation. Vegetation indices such as Normalized Difference Vegetation Index (NDVI), Photochemical Reflectance Index (PRI), Structure Insensitive Pigment Index (SIPI), and Chlorophyll Index (CI) indicated that B stress reduces chlorophyll levels and may induce carotenoid accumulation, suggesting a photosynthetic tolerance mechanism. Although quantitative prediction of leaf B content proved more challenging, simulations showed that even modest prediction accuracies can substantially boost genetic gains if larger populations are screened, and selection intensities are increased. These findings underscore the value of hyperspectral radiometry for high-throughput phenotyping, allowing breeders to rapidly identify and advance B-tolerant rootstocks.

plant biology↗

bioRxiv2025

The Genetic Basis of Chloride Exclusion in Grapevines

Mediterranean regions are among the most important areas for global grape production, characterized by dry climates and frequent challenges associated with soil salinity. In these environments, chloride toxicity is a major factor limiting vine growth and fruit quality. Despite the critical role of chloride exclusion in salinity tolerance, the genetic mechanisms underlying this trait remain poorly understood. In this study, we leveraged one of the largest Vitis germplasm collections, comprising 335 accessions from 18 wild and cultivated Vitis species, to characterize natural variation in chloride exclusion. This diverse panel, which includes accessions from the southwestern United States and Mexico, captures a broad range of evolutionary adaptations to abiotic stress, providing an unprecedented opportunity to investigate the genetic basis of salinity tolerance. Using genome-wide association (GWA) and quantitative trait loci (QTL) mapping, we identified a major QTL on chromosome 8 containing candidate genes encoding cation/H exchangers (CHX), which are involved in ion transport and homeostasis. To validate these findings, we analyzed a mapping population derived from V. acerifolia longii 9018 and the commercial rootstock GRN3, confirming the chromosome 8 locus as a major determinant of chloride exclusion. Structural variant analysis revealed key non-synonymous substitutions within CHX genes, suggesting potential functional roles in salinity tolerance. Additionally, we discovered a novel QTL on chromosome 19 enriched with G-type lectin S-receptor-like serine/threonine-protein kinases, known regulators of stress signaling. By integrating extensive phenotypic and genomic data across a diverse Vitis collection, this study provides novel insights into the genetic architecture of chloride exclusion and identifies valuable candidate genes for breeding salt-tolerant rootstocks.

genetics↗

bioRxiv2025

Specific neuroblast-derived signals control both cell migration and fate in the rostral migratory stream

Functional neuronal circuits require neuroblasts migrate to appropriate locations and then differentiate into neuronal subtypes. However, it remains unknown how neuroblasts in the subventricular zone (SVZ) are guided through the rostral migratory stream (RMS) to the olfactory bulb (OB). Here we define EphB2 as a neuroblast-derived cue that controls migration along the RMS and helps to determine cell fate. Within the RMS, EphB2 is expressed selectively in, kinase-active in, and required for the migration of neuroblasts. As neuroblasts enter the OB and differentiate, EphB kinase activity is down-regulated, and in the granule cell layer (GCL), EphB2 expression is down-regulated. Blocking EphB kinase activity or knocking down EphB2 results in defects in migration and premature cellular differentiation in the RMS. Unexpectedly, premature loss of EphB2 expression causes neuroblasts to stop migrating and differentiate into astrocyte-like cells. Thus, EphB2 kinase activity and expression are linked to migration and specification of neuroblast fate.

neuroscience↗

bioRxiv2025

The oncogenic CCDC6-RET fusion product is a dual ATP and ADP-dependent kinase that functions via cis-phosphorylation

Gene fusions products involving protein kinases are known drivers in human cancers and actionable targets for personalized therapy, yet the structural and molecular determinants that control their function are largely unexplored. Here we show that a CCDC6-RET fusion product, a driver and therapeutic target in lung and thyroid cancers, is a highly active dimeric kinase in solution. Time-resolved mass spectrometry analysis together with a robust biochemical and biophysical characterization reveal that CCDC6-RET functions as a dual ATP- and ADP-dependent kinase able to bind both nucleotides and uses them as phosphoryl donors. We also identify a crosstalk between the c-terminal and the activation segments, uncovering a mutually exclusive dependency by the former on activation loop phospho-sites controlling both the processing and the catalytic activity of the fusion protein. Furthermore, we generated a 3D-assembly of a CCDC6-RET homodimer combining electron microscopy (EM) single particle, small-angle X-ray scattering (SAXS) and in silico structural analyses. Our structural model together with cross-linking mass spectrometry data demonstrated that CCDC6-RET forms a face-to-face trans-inhibited dimer in the apo state characterized by intermolecular-crosslinked activation segments. Upon nucleotide binding and catalytic domains reorientation, fast activation loop phosphorylation is driven by a mechanism in cis. Our work uncover for the first time the molecular and structural determinants that controls CCDC6-RET function and provides a solid framework to study the structure and function of other RET fusion products.

biochemistry↗

bioRxiv2024

Global diversity of soil-transmitted helminths reveals population-biased genetic variation that impacts diagnostic targets

Soil-transmitted helminths (STHs) are intestinal pathogens affecting over a billion people worldwide. STH control relies on microsopy-based diagnostics to monitor parasite prevalence and enable post-treatment surveillance, however, molecular diagnostics are rapidly being developed due to increased sensitivity, particularly in low-STH-prevalence settings. The genetic diversity of helminths and its potential impact on molecular diagnostics remains unclear. Using low-coverage genome sequencing, we assessed the presence of STHs in worm, faecal and purified egg samples from 27 countries, identifying differences in the genetic connectivity and diversity of STH-positive samples across regions and cryptic diversity between closely related human- and pig-infective species. We defined substancial copy number and sequence variants in current diagnostic targets and validated the impact of genetic variants on qPCR diagnostics using in vitro assays. Our study provides insights into the diversity and genomic epidemiology of STHs, highlighting challenges and opportunities for developing molecular diagnostics needed to support STH control efforts.

genomics↗

bioRxiv2023

Latitudinal gradients in predation persist in urban environments

Urbanization can profoundly disrupt local ecology. But while urban areas now stretch across latitudes, little is known about urbanizations effects on macroecological patterns. We used standardized experiments to test whether urbanization disrupts latitudinal gradients in seed predation, a macroecological pattern that shapes community assembly and diversity. Using >56,000 seeds, we compared predation in urbanized and natural areas across 14,000 km of latitude, spanning the Americas. Predation increased 5-fold from high latitudes to the tropics, and latitudinal gradients in predation persisted in urban areas despite significant habitat modification. Urbanization reduced predation by vertebrates, but not invertebrates, and seemed to increase ant predation specifically. Our results show that macroecological patterns in predation intensity can persist in urbanized environments, even as urbanization alters the relative importance of predators. One-Sentence SummaryAcross 56,000 seeds and 112{degrees} of latitude, latitudinal gradients in seed predation are equally strong in natural vs. urban areas

ecology↗

bioRxiv2023

Detailed Survey of an in-vitro Intestinal Epithelium Model by Single-Cell Transcriptomics

The gut plays a critical role in maintaining human health by facilitating the absorption of nutrients, regulating metabolism, and interacting with the immune system and gut microbiota. The co-culture of two human colorectal cancer cell lines, Caco-2 and HT29, on Transwell is commonly used as an in vitro gut mimic in studies of intestinal absorption pharmacokinetics, gut mechanics, and gut-microbe interplay given the similar morphology, expression of transporters and enzymes, and barrier function. However, to sufficiently evaluate the translatability of insights from such a system to human physiological contexts, a detailed survey of cell type heterogeneity in the system and a holistic comparison with human physiology are needed to be conducted rather than by the presence of a few well-studied proteins. Single-cell RNA sequencing provides high-resolution expression profiles of cells in the co-culture, enabling the heterogeneity to be characterized and the similarity to human epithelial cells to be evaluated. Transcriptional profiles of 16019 genes in 13784 cells were acquired and compared to human epithelial cells (GSE185224). We identified the intestinal stem cell-, transit amplifying-, enterocyte-, goblet cell-, and enteroendocrine-like cells together with differentiating HT29 cells in the system based on the expression of canonical markers in healthy adult human epithelial cells. The epithelium-like co-culture was fetal intestine-like, with less variety of gene expression compared to the human gut. Transporters for major types of substance (lipid, amino acid, ion, water, etc.) were found transcribed in the majority of the enterocytes-like cells in the system. However, some of the well-studied transporters such as FATP4 and GLUT2 were absent. Toll-like receptors were not highly expressed in the sample, yet the treatment of lipopolysaccharide still caused a mild change in trans-epithelial electrical resistance and gene expression, possibly by the interaction with CD14, the co-receptor for TLRs. Overall, the Caco-2/HT29 co-culture is a cost-effective epithelium model for drug permeability testing or mechanical simulation, but its phenotypic discrepancy with the real epithelium is not negligible. As a result, its response to biological factors might not provide transferrable knowledge to the study of human gut physiology, especially the innate immune aspect.

cell biology↗

bioRxiv2023

Feedback control of organ size precision is mediated by BMP2-regulated apoptosis in the Drosophila eye

Biological processes are intrinsically noisy and yet, the result of development -like the species-specific size and shape of organs- is usually remarkably precise. This precision suggests the existence of mechanisms of feedback control that ensure that deviations from a target size are minimized. Still, we have very limited understanding of how these mechanisms operate. Here, we investigate the problem of organ size precision using the Drosophila eye. The size of the adult eye depends on the rates at which eye progenitor cells grow and differentiate. We first find that the progenitor net growth rate results from the balance between their proliferation and apoptosis, with this latter contributing to determining both final eye size and its variability. In turn, apoptosis of progenitor cells is hampered by Dpp, a BMP2/4 signaling molecule transiently produced by early differentiating retinal cells. Our genetic and computational experiments show how the status of retinal differentiation is communicated to progenitors through the differentiation-dependent production of Dpp which, by adjusting the rate of apoptosis, exerts a feedback control over the net growth of progenitors to reduce final eye size variability.

developmental biology↗

bioRxiv2022

Peroxiredoxin 2 is required for the redox mediated adaptation to exercise

Exercise generates a site-specific increase in Reactive Oxygen Species (ROS) within muscle required for a beneficial adaptive response by activation of specific signalling pathways. Here, we demonstrate that Peroxiredoxin 2 (Prdx2), an abundant cytoplasmic 2-Cys peroxiredoxin, is required for the adaptive beneficial hormesis response to H2O2. A short bolus addition of H2O2 increases mitochondrial capacity and improves myogenesis of cultured myoblasts, this beneficial adaptive response was suppressed in myoblasts with decreased expression of cytoplasmic Prdxs. A swimming exercise protocol in C. elegans increased mitochondrial content, fitness, survival and longevity in wild type (N2) worms. In contrast, prdx-2 mutant worms had decreased fitness, disrupted mitochondria, reduced survival and lifespan following exercise. Global proteomics following exercise identified distinct changes in the proteome of N2 and prdx-2 mutants. Furthermore, a redox proteomic approach to quantify reversible oxidation of individual Cysteine residues revealed a relatively more oxidised redox state following exercise in the prdx-2 mutants. Our results demonstrate that conserved cytoplasmic 2-Cys Peroxiredoxins are required for the beneficial adaptive response to a physiological stress.

molecular biology↗

bioRxiv2022

An allosteric switch between the activation loop and a c-terminal palindromic phospho-motif controls c-Src function

Auto-phosphorylation controls the transition between discrete functional and conformational states in protein kinases, yet the structural and molecular determinants underlaying this fundamental process remain unclear. Here we show that c-terminal Tyr 530 is a de facto c-Src auto-phosphorylation site with slow time-resolution kinetics and strong intermolecular component. On the contrary, activation-loop Tyr 419 undergoes fast kinetics and a cis-to-trans phosphorylation-switch that controls c-terminal Tyr 530 auto-phosphorylation, enzyme specificity and strikingly, c-Src non-catalytic function as a substrate. In line with this, we visualize by X-ray crystallography a snapshot of Tyr 530 intermolecular phosphorylation in which a c-terminal palindromic phospho-motif flanking Tyr 530 on the susbtrate molecule engages the P-loop of the active kinase for ready entry prior catalysis. Perturbation of the phospho-motif accounts for c-Src disfunction as indicated by viral and a colorectal cancer (CRC) associated c-terminal deleted variants. We show that c-terminal residues 531 to 536 are required for c-Src Tyr 530 and global auto-phosphorylation, and this detrimental effect is caused by the susbtrate molecule inhibiting allosterically the active kinase. Our work reveals a bi-directional crosstalk between the activation and c-terminal segments that controls the allosteric interplay between susbtrate and enzyme acting kinases during auto-phosphorylation HighlightsO_LIA bi-directional phospho-switch connecting the activation and c-terminal segments controls c-Src function C_LIO_LIActivation-loop Tyr 419 is required for c-terminal Tyr 530 auto-phosphorylation, enzyme specificity and non-catalytic function as a substrate C_LIO_LIBiochemical and structural visualization of c-Src Tyr 530 intermolecular auto-phosphorylation C_LIO_LIA double-phosphorylated c-Src on both the activation and c-terminal segments is a fully active protein C_LIO_LICancer associated c-terminal deleted variants inhibit allosterically c-Src activity by a dominant negative effect C_LI

biochemistry↗

bioRxiv2022

Latent Interacting Variable-Effects Modeling of Gut Microbiome Multi-Omics in Inflammatory Bowel Disease

Latent Interacting Variable Effects (LIVE) modeling is a framework to integrate different types of microbiome multi-omics data by combining latent variables from single-omic models into a structured meta-model to determine discriminative, interacting multi-omics features driving disease status. We implemented and tested LIVE modeling in publicly available metagenomics and metabolomics datasets from Crohns Disease and Ulcerative Colitis patients. Here, LIVE modeling reduced the number of feature correlations from the original data set for CD and UC to tractable numbers and facilitated prioritization of biological associations between microbes, metabolites, enzymes and IBD status through the application of stringent thresholds on generated inferential statistics. We determined LIVE modeling confirmed previously reported IBD biomarkers and uncovered potentially novel disease mechanisms in IBD. LIVE modeling makes a distinct and complementary contribution to the current methods to integrate microbiome data to predict IBD status because of its flexibility to adapt to different types of microbiome multi-omics data, scalability for large and small cohort studies via reliance on latent variables and dimensionality reduction, and the intuitive interpretability of the linear meta-model integrating -omic data types. The results of LIVE modeling and the biological relationships can be represented in networks that connect local correlation structure of single omic data types with global community and omic structure in the latent variable VIP scores. This model arises as novel tool that allows researchers to be more selective about omic feature interaction without disrupting the structural correlation framework provided by sPLS-DA interaction effects modeling. It will lead to form testable hypothesis by identifying potential and unique interactions between metabolome and microbiome that must be considered for future studies. AUTHOR SUMMARYLatent Interacting Variable Effects (LIVE) modeling integrates microbiome multiomics features by encoding them in a set of latent variables (LVs) from single-omic sparse Partial Lease Squares models, and then combine these LVs into structured metamodel to determine the most discriminative features driving IBD. We used publicly available metagenomic and metabolomics data from Crohns Disease and Ulcerative Colitis patients to develop LIVE modeling. LIVE modeling reduced data dimensionality efficiently and identified statistical interactions among microbiome multi-omics data, which can be visualized as a mineable network data structure. LIVE modeling confirmed features previously reported and revealed novel microbiome interactions in IBD. LIVE offers a flexible framework for multi-omic modeling that may aid in interpretation of complex microbiome datasets.

systems biology↗

bioRxiv2022

Induction of senescence renders cancer cells highly immunogenic

Cellular senescence is a stress response that activates innate immunity. However, the interplay between senescent cells and the adaptive immune system remains largely unexplored. Here, we show that senescent cells display enhanced MHC class I (MHC-I) antigen processing and presentation. Immunization of mice with senescent syngeneic fibroblasts generates CD8 T cells reactive against both normal and senescent fibroblasts, some of them targeting senescence-associated MHC-I-peptides. In the context of cancer, we demonstrate that senescent cancer cells trigger strong anti-tumor protection mediated by antigen-presenting cells and CD8 T cells. This response is superior to the protection elicited by cells undergoing immunogenic cell death. Finally, induction of senescence in patient-derived cancer cells exacerbates the activation of autologous tumor-reactive CD8 tumor-infiltrating lymphocytes (TILs) with no effect on non-reactive TILs. Our study indicates that immunization with senescent cancer cells strongly activates anti-tumor immunity, and this can be exploited for cancer therapy. STATEMENT OF SIGNIFICANCEOur study shows that senescent cells are endowed with a high immunogenic potential, superior to the gold standard of immunogenic cell death. The induction of senescence in cancer cells can be exploited to develop efficient and protective CD8-dependent anti-tumor immune responses.

cancer biology↗

bioRxiv2022

Mast cells impair melanoma cell homing and metastasis by inhibiting HMGA1 secretion.

Metastatic disease is the major cause of death from cancer. From the primary tumor, cells remotely prepare the environment of the future metastatic sites by secreted factors and extracellular vesicles. During this process, known as pre-metastatic niche formation, immune cells play a crucial role. Mast cells are hematopoietic bone marrow-derived innate immune cells whose function in lung immune response to invading tumors remains to be defined. We found reduced melanoma lung metastasis in mast cell deficient mouse models (Wsh and MCTP5-Cre-RDTR), supporting a pro-metastatic role for mast cells in vivo. However, due to evidence pointing to their antitumorigenic role, we studied the impact of mast cells in melanoma cell function in vitro. Surprisingly, in vitro co-culture of bone-marrow derived mast cells with melanoma cells showed that they have an intrinsic anti-metastatic activity. Mass spectrometry analysis of melanoma-mast cell co-cultures secretome showed that HMGA1 secretion by melanoma cells was significantly impaired. Consistently, HMGA1 knock down in B16-F10 cells reduced their metastatic capacity in vivo. Importantly, analysis of HMGA1 expression in human melanoma tumors showed that metastatic tumors with high HMGA1 expression are associated with reduced overall and disease-free survival. Moreover, we show that HMGA1 is reduced in the nuclei and enriched in the cytoplasm of melanoma metastatic lesions when compared to primary tumors. These data suggest that high HMGA1 expression and secretion from melanoma cells promotes metastatic behavior. Targeting HMGA1 expression intrinsically or extrinsically by mast cells actions reduce melanoma metastasis. Our results pave the way to the use of HMGA1 as anti-metastatic target in melanoma as previously suggested in other cancer types.

cancer biology↗