Une meilleure connaissance des mécanismes moléculaires associés à l’agressivité et au fort taux de récidive des cancers pulmonaires non à petites cellules est nécessaire afin d’identifier de nouveaux biomarqueurs et de nouvelles cibles thérapeutiques et d’améliorer la prise en charge des patients. Dans ce contexte, cette revue fait un point non exhaustif sur la famille émergente des longs ARNs non codants, d’importants régulateurs de l’expression génique, fréquemment dérégulés dans les cancers et en réponse à l’hypoxie, un facteur environnemental qui joue un rôle important dans le développement, l’agressivité et la résistance aux traitements de ces tumeurs.

Periodontitis, a prevalent and costly oral disease, remains incompletely understood in its etiopathogenesis. The conventional model attributes it to pathogenic bacteria, but emerging evidence suggests dysbiosis involving bacteria, herpesviruses, and an exaggerated host immune response. Among herpesviruses, Epstein-Barr virus (EBV) closely links to severe periodontitis, yet the mechanisms underlying EBV-related pathogenesis remain elusive. This study examined the presence, methylation patterns, and infection states of EBV in gingival tissues from healthy patients and those with periodontitis. It also assessed gene expression differences associated with EBV through whole-genome transcriptomic profiling in healthy and periodontitis-affected tissues. EBV DNA was found at similar frequencies in healthy and periodontitis tissues, suggesting common EBV infection even before disease manifestation. In healthy tissues, mostly unmethylated EBV genomes indicated lytic infection in gums, consistent with the literature on lytic EBV spread in epithelia and continual significant virus release in the saliva of healthy carriers. Conversely, EBV DNA in periodontitis tissues showed both methylated and unmethylated patterns, suggesting a mix of latent and lytic genomes. This indicates the coexistence of latent EBV in B-cells and lytic EBV in plasma cells (PCs), linking EBV presence with both cell types in periodontitis. Whole-genome transcriptomic analysis revealed distinct expression profiles in EBV-positive periodontitis tissues, with upregulated genes associated with inflammatory/immune responses and B-cell and PC markers, while downregulated genes were related to epithelial structure and organization. The EBV-positive periodontitis signature differed distinctly from that of EBV-positive healthy gums, eliciting only a typical viral-induced immune response. These findings provide new insights into EBV physiopathology in the gum, notably assigning a direct etiopathogenetic contribution to EBV in periodontitis. The results suggest a model where EBV can commonly, and apparently asymptomatically, spread in healthy gingiva but may also aggravate inflammation in the context of gum dysbiosis, involving infiltration of B-cells and PCs and loss of epithelial integrity.

A better understanding of the molecular mechanisms associated with the aggressiveness and high recurrence rate of non-small cell lung cancers is needed to identify new biomarkers and therapeutic targets to improve patient management. In this context, this review provides a non-exhaustive update on the emerging family of long non-coding RNAs, important regulators of gene expression, frequently deregulated in cancers and in response to hypoxia - an environmental factor that plays an important role in the development, aggressiveness and treatment resistance of these tumors. (c) 2025 Published by Elsevier Masson SAS on behalf of SPLF.

Introduction The aim of this project is to determine whether single-cell transcriptomics (sc-RNAseq) can provide information susceptible to enrich classical bulk transcriptomics experiments in toxicology. In the present work, we studied the effects of a non-genotoxic carcinogen (CdCl2) on human airway pseudostratified epithelium. Methods The identification of cell-type-specific gene expression signatures was performed through scRNA-seq analyses using PARSE technology on human airway bronchial epithelial cells (HAEC) cultured in 3D at an air-liquid interface (ALI) and exposed to 10μM CdCl2, an heavy metal pollutant present in cigarette smoke. These cell-type specific responses signatures were validated through RNA-Fluorescence In Situ Hybridizations. Results Single-cell gene profiling indicated that different regulons are modulated in a cell-type-specific manner in response to CdCl2 exposure. For instance, we showed that treatment with CdCl2 stimulated the expression of MT1G, MT1M and to a lesser extent SLC30A1 and HMOX1 preferentially in multiciliated and mucus-secreting cells, while AKT3 and IL1RN are rather induced in basal cells. Among the cadmium-regulated genes, we found that the long non-coding RNA LUCAT1 is induced in specific differentiated cell types. We previously showed1 that LUCAT1 is i) upregulated by hypoxia in lung adenocarcinomas, ii) correlated with poor prognosis in patients and iii) involved in the regulation of oxidative stress in cancer cells. However, its cellular sourcing and physiological role in the differentiated mucociliary airway epithelium have not yet been addressed. We found that LUCAT1 is slightly expressed in the untreated epithelium, but in response to hypoxia or CdCl2, it is markedly induced in suprabasal and deuterosomal cells and in differentiated secretory and multiciliated cells but not in basal cells. Using a CRISPR-Cas9-RNP approach2 to knockdown LUCAT1 in basal bronchial stem cells, we will decipher the cell state-specific functions of this gene i) in the regeneration steps of a fully differentiated mucociliary human airway epithelium and, ii) in hypoxia- and CdCl2-responses. Conclusion ScRNA-seq reveals distinct transcriptional responses to CdCl2 among airway epithelial cell subtypes. This method could be applied to other molecules to classify gene expression variations and develop predictive tests for non-genotoxic carcinogens compounds. This study also precise the physiological role of LUCAT1 in the homeostasis, regeneration and stress-response of HAEC.

IntroductionLung fibrosis, including idiopathic pulmonary fibrosis (IPF), results from dysfunctional wound repair involving different cell types, including fibroblasts, epithelial cells and macrophages, which respond to multiple soluble and matrix factors. Fibroblast growth factor (FGF) signaling has been implicated in the pathogenesis of lung fibrosis, in particular in the regulation of fibroblast to myofibroblast transition (FMT), cell proliferation, and extracellular matrix production. However, individual FGF family members may exert pro- and anti-fibrotic effects, depending on the responding cell, the expression levels of the different FGF receptors (FGFR1-4) and the context of other signaling molecules, such as Transforming growth factor β (TGF-β). In order to better understand the complex functions of FGFs on pulmonary fibrosis, we evaluated the effect of a modified version of a FGFR3 decoy receptor [1] that specifically sequesters FGFR3 ligands including FGF1, FGF2 and FGF9 as a potential anti-fibrotic drug.MethodsThe effect of several FGFs in the presence or the absence of the FGFR3 ligand Trap was evaluated in vitro on human lung fibroblasts from healthy donors and IPF patients on various fibrotic parameters such as cell proliferation, cell contraction, production of extracellular matrix (ECM) and modulation of signaling pathways. The effect of the FGFR3 ligand trap was also assessed in vivo on the bleomycin mouse model, by monitoring mice body weight, Ashcroft score, hydroxyproline and soluble collagen content.ResultsOur results revealed that FGFs (mainly FGF2) stimulate fibroblast proliferation, contraction, ECM production and expression of various fibrotic markers such as chemokine ligand 2 (CCL2), connective tissue growth factor (CTGF), interleukin 6 (IL6), interleukin receptor 4 (IL4R) or ECM-related genes like fibronectin (FN1). The FGFR3 ligands Trap was able to reduce this FGF mediated pro-fibrotic phenotype and to desensitize the TGF-β canonical pathway in IPF cells. In the bleomycin lung fibrosis mouse model, the FGFR3 ligands Trap partially reversed lung fibrosis, as evidenced by a reduced body weight loss as well as diminution of the aschcroft score, hydroxyproline and soluble collagen content in lung samples.ConclusionOur data highlight the interplay between the TGF-β and the FGF signaling pathways in pulmonary fibrosis and demonstrate the potential of targeting FGFR3 signaling as a novel therapy for IPF.

Introduction Current treatments for lung adenocarcinomas (LUAD) have poor response rates and there is an urgent need to propose new strategies to prevent these escape routes. Variability in LUAD drug response is multifactorial including intrinsic altered pathways or extrinsic factors such as hypoxia. Recent advances in cancer genomics have highlighted aberrant expression of ncRNAs as a major determinant of early treatment resistance. We aim here at gaining new insights into the functions of lncRNAs on the hypoxic response of LUAD cells. Methods We have developed a single-cell CRISPR-interference-based (CRISPRi) transcriptome screening on our best lncRNA candidates based on the CROP-Seq approach (Daltinger et al. Nat Methods 2017). A mini-CROP-seq library including validated gRNAs targeting 8 lncRNA candidates and several key regulators of the hypoxic response (HIF1A, HIF2A) has been amplified and transduced in A549 LUAD cells cultured in normoxia or hypoxia. The cells from the 2 conditions were then pooled, labelled with barcoded antibodies and analyzed by single-cell RNA-Seq in a single run, directly linking guide RNA expression to transcriptome responses in individual cells. Results We describe here the precise workflow and the validation of the method on key regulators of the hypoxic response. Moreover, our data indicate that several lncRNAs may be involved in the regulation of cell survival, cell adhesion and/or hypoxic response. Conclusion In Conclusion, this method should improve the knowledge on lncRNA-associated functions and provide new potential targets associated with drug resistance in lung cancer.

Le pneumomédiastin, secondaire ou spontané est défini par la présence d’air au sein du médiastin, mis en évidence sur une radiographie thoracique et/ou un scanner thoracique. Le pneumomédiastin secondaire s’observe dans des contextes variés (traumatisme thoracique, perforation des voies aériennes centrales ou du tube digestif, pneumothorax, barotraumatisme lié à la ventilation mécanique…). Le pneumomédiastin spontané (PMSp) survient sans qu’on puisse incriminer une des causes de pneumomédiastin secondaire.Le PMSp est une pathologie rare, affectant le plus souvent le jeune adulte. Le diagnostic positif peut reposer sur la radiographie pulmonaire mais la tomodensitométrie est plus sensible. La distinction entre PMSp et pneumomédiastin secondaire est en général aisée mais elle peut parfois être plus difficile, notamment en cas de perforation œsophagienne. L’évolution du PMSp est le plus souvent bénigne mais de rares complications peuvent s’observer. Le traitement est le plus souvent conservateur.Il n’y a pas de prise en charge consensuelle du fait de l’absence d’essais randomisés. La tendance est de proposer une simple surveillance, éventuellement en ambulatoire.Le PMSp est une maladie affectant principalement le sujet jeune et dont l’évolution est le plus souvent bénigne.Pneumomediastinum, which can be spontaneous or secondary, is defined by the presence of free air in the mediastinum as shown on a chest X-ray and/or chest CT, with or without subcutaneous emphysema. Secondary pneumomediastinum develops in various contexts (thoracic traumatism, perforation of central airway or digestive tract, pneumothorax, barotraumatism complicating mechanical ventilation…). Spontaneous pneumomediastinum , which will be the focus of this review, develops without any of the above-mentioned conditions.Spontaneous pneumomediastinum is a rare entity which usually occurs in young people either without medical history or with an history of asthma. A trigger event is detected in 40% to 60% of cases. Positive diagnosis is made on chest radiographt but thoracic CT is more sensitive. Distinction between spontaneous pneumomediastinum and secondary pneumomediastinum is in general easy but may sometimes be more difficult, particularly in case of oesophageal perforation. The evolution of spontaneous pneumomediastinum is most often benign but, rare complications may occur. Management is most often conservative.There is no consensual management of spontaneous pneumediastinum because of the lack of randomized prospective studies. This may be explained by the rarity of the disease. The actual trend is to offer to the patients a conservative treatment, which could be ambulatory in some cases.Spontaneous pneumomediastinum is a rare entity developing mainly in young subjects. The evolution is in general benign, justifying a conservative approach.

Lineage dedifferentiation towards a mesenchymal-like state is a common mechanism of adaptive response and resistance to targeted therapy in melanoma. Yet, the transcriptional network driving this phenotypic plasticity remains elusive. Remarkably, this cellular state displays myofibroblast and fibrotic features and escapes MAPK inhibitors (MAPKi) through extracellular matrix (ECM) remodeling activities. Here we show that the anti-fibrotic drug Nintedanib/BIBF1120 is active to normalize the fibrous ECM network, enhance the efficacy of MAPK-targeted therapy and delay tumor relapse in a pre-clinical model of melanoma. We also uncovered the molecular networks that regulate the acquisition of this resistant phenotype and its reversion by Nintedanib, pointing the miR-143/-145 pro-fibrotic cluster as a driver of the therapy-resistant mesenchymal-like phenotype. Upregulation of the miR-143/-145 cluster under BRAFi/MAPKi therapy was observed in melanoma cells in vitro and in vivo and was associated with an invasive/undifferentiated profile of resistant cells. The 2 mature miRNAs generated from this cluster, miR-143-3p and miR-145-5p collaborated to mediate phenotypic transition towards a drug resistant undifferentiated mesenchymal-like state by targeting Fascin actin-bundling protein 1 (FSCN1), modulating the dynamic crosstalk between the actin cytoskeleton and the ECM through the regulation of focal adhesion dynamics as well as contributing to a fine-tuning of mechanotransduction pathways. Our study brings insights into a novel miRNA-mediated regulatory network that contributes to non-genetic adaptive drug resistance and provides proof-of-principle that preventing MAPKi-induced pro-fibrotic stromal response is a viable therapeutic opportunity for patients on targeted therapy.

Matrix metalloproteinases (MMPs) have been traditionally implicated in cancer progression because of their ability to degrade the extracellular matrix. However, some members of the MMP family have recently been identified as proteases with antitumor properties. Thus, it has been described that collagenase-2 (MMP-8) has a protective role in tumor and metastasis progression, but the molecular mechanisms underlying these effects are unknown. We show herein that Mmp8 expression causes a decrease in miR-21 levels that in turn leads to a reduction in tumor growth and lung metastasis formation by MDA-MB-231 (4175) breast cancer cells. By using both in vitro and in vivo models, we demonstrate that the mechanism responsible for these MMP-8 beneficial effects involves cleavage of decorin by MMP-8 and a subsequent reduction of transforming growth factor β (TGF-β) signaling that controls miR-21 levels. In addition, miR-21 downregulation induced by MMP-8 increases the levels of tumor suppressors such as programmed cell death 4, which may also contribute to the decrease in tumor formation and metastasis of breast cancer cells overexpressing this metalloproteinase. These findings reveal a new signaling pathway for cancer regulation controlled by MMP-8, and contribute to clarify the molecular mechanisms by which tumor-defying proteases may exert their protective function in cancer and metastasis.