Hepatic metastasis is a clinical challenge for colorectal cancer (CRC). Senescent cancer cells accumulate in CRC favoring tumor dissemination. Whether this mechanism progresses also in metastasis is unexplored. Here, we integrated spatial transcriptomics, 3D‐microscopy, and multicellular transcriptomics to study the role of cellular senescence in human colorectal liver metastasis (CRLM). We discovered two distinct senescent metastatic cancer cell (SMCC) subtypes, transcriptionally located at the opposite pole of epithelial (e) to mesenchymal (m) transition. SMCCs differ in chemotherapy susceptibility, biological program, and prognostic roles. Mechanistically, epithelial (e)SMCC initiation relies on nucleolar stress, whereby c‐myc dependent oncogene hyperactivation induces ribosomal RPL11 accumulation and DNA damage response. In a 2D pre‐clinical model, we demonstrated that RPL11 co‐localized with HDM2, a p53‐specific ubiquitin ligase, leading to senescence activation in (e)SMCCs. On the contrary, mesenchymal (m)SMCCs undergo TGFβ paracrine activation of NOX4‐p15 effectors. SMCCs display opposing effects also in the immune regulation of neighboring cells, establishing an immunosuppressive environment or leading to an active immune workflow. Both SMCC signatures are predictive biomarkers whose unbalanced ratio determined the clinical outcome in CRLM and CRC patients. Altogether, we provide a comprehensive new understanding of the role of SMCCs in CRLM and highlight their potential as new therapeutic targets to limit CRLM progression.

The role of single nucleotide polymorphisms (SNPs) in the etiopathogenesis of cardiovascular diseases is well known. The effect of SNPs on disease predisposition has been established not only for protein coding genes but also for genes encoding microRNAs (miRNAs). The miR‐143/145 cluster is smooth muscle cell‐specific and implicated in the pathogenesis of atherosclerosis. Whether SNPs within the genomic sequence of the miR‐143/145 cluster are involved in cardiovascular disease development is not known. We thus searched annotated sequence databases for possible SNPs associated with miR‐143/145. We identified one SNP, rs41291957 (G > A), located −91 bp from the mature miR‐143 sequence, as the nearest genetic variation to this miRNA cluster, with a minor allele frequency > 10%. In silico and in vitro approaches determined that rs41291957 (A) upregulates miR‐143 and miR‐145, modulating phenotypic switching of vascular smooth cells towards a differentiated/contractile phenotype. Finally, we analysed association between rs41291957 and CAD in two cohorts of patients, finding that the SNP was a protective factor. In conclusion, our study links a genetic variation to a pathological outcome through involvement of miRNAs.

Malignant bile duct obstruction is typically treated by biliary stenting, which however increases the risk of bacterial infections. Here, we analyzed the microbial content of the biliary stents from 56 patients finding widespread microbial colonization. Seventeen of 36 prevalent stent species are common oral microbiome members, associate with disease conditions when present in the gut, and include dozens of biofilm- and antimicrobial resistance-related genes. This work provides an overview of the microbial communities populating the stents.

Background: Intrahepatic cholangiocarcinoma (iCCA) is a highly aggressive biliary tract cancer with a poor prognosis and a complex tumour microenvironment (TME) that remains poorly understood. Objective: This study aimed to investigate the phenotypic and molecular characteristics of B lymphocytes, their interactions with the TME and their prognostic implications. Design: B-cell compartments in the tumour, peritumour, and peripheral blood of iCCA patients were analysed using multimodal single-cell technologies. The B-cell interactome with the iCCA TME was explored in silico, and ex vivo assays assessed the impact of interactions with cancer-associated fibroblasts (CAFs) and tumour cells on B-cell biology. B-cell modulation during chemoimmunotherapy in advanced iCCA was also evaluated. Results: B cells were enriched in adjacent tumour-free tissues and formed mature tertiary lymphoid structures (TLS), correlating with better prognosis. Conversely, tumour-infiltrating B cells were scarce, immature and displayed reduced effector function with increased immunosuppressive features. Coculture with tumour cells or CAFs impaired B-cell differentiation and function, including downregulation of BAFFR in peripheral B cells. IL-6 and TGF-β emerged as major drivers of B-cell dysfunction; dual blockade restored B-cell activation and differentiation. Elevated frequencies of circulating BAFFR ⁺ B cells and hyperexpanded clonotypes were linked to improved chemoimmunotherapy response. Conclusions: iCCA is characterised by a profoundly immunosuppressive TME that impairs B-cell function through soluble factors and cellular interactions. Our findings identify B cells as biomarkers and therapeutic targets, supporting strategies to restore B-cell function and promote mature TLS to enhance immunotherapy responsiveness in iCCA.

Esophageal cancer is a highly lethal malignancy, representing 5% of all cancer-related deaths. The two main subtypes are esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC). While most research has focused on ESCC, few studies have analyzed EAC for transcriptional signatures linked to diagnosis or prognosis. In this study, we utilized single-cell RNA sequencing and bulk RNA sequencing to identify specific immune cell types that contribute to anti-tumor responses, as well as differentially expressed genes (DEGs). We have characterized transcriptional signatures, validated against a wide cohort of TCGA patients, that are capable of predicting clinical outcomes and the prognosis of EAC post-surgery with efficacy comparable to the currently accepted prognostic factors. In conclusion, our findings provide insights into the immune landscape and therapeutic targets of EAC, proposing novel immunological biomarkers for predicting prognosis, aiding in patient stratification for post-surgical outcomes, follow-up, and personalized adjuvant therapy decisions.

BACKGROUND: Hereditary hemorrhagic telangiectasia (HHT) is a genetic disorder caused by pathogenic variants in the endothelial TGFβ/BMP pathway, crucial for the vascular arterial-venous differentiation. Vascular defects result in fragile and malformed vessels. The precise mechanisms driving vascular network failure remain incompletely understood, complicating the design of targeted therapies. METHODS: Nasal telangiectasias from HHT patients carrying variants in ACVRL1 or ENG were used to perform scRNA-seq (2 ACVRL1- and 1 ENG-patient) and spatial transcriptomics (1 ACVRL1 and 1 ENG) to uncover endothelial cells (EC) populations. Vascular characteristics within biopsies were evaluated using transmission electron microscopy (TEM) (1 ACVRL1 and 1 ENG) and histological analyses (23 ACVRL1 and 7 ENG), with particular attention to regions exhibiting varying degrees of damage. RESULTS: Comparing our HHT tissues with healthy donor from the literature, we identified cellular heterogeneity within EC populations, revealing two distinct venous clusters: a stable, quiescent population (Mature Vein) and an activated, pro-inflammatory population (HHT Vein). The coexistence of these two clusters suggests cellular diversity within the biopsy, further validated by TEM and histology, revealing a juxtaposition of well-organized collagen and cellular architecture with severely disrupted, fibrotic regions. Moreover, cellular crosstalk analyses allowed us to identify critical ligands in ECs that interact with fibroblasts and mural cells. In particular, we found Midkine (MDK) lost in HHT Vein ECs with further validation in vitro, suggesting its potential role in cellular stability. Furthermore, spatial transcriptomics allowed to further uncover pathologic phenotypes in cells neighboring HHT Vein ECs. CONCLUSIONS: HHT biopsies exhibit localized inflamed and fibrotic vascular areas with the presence of different transcriptional sub-populations of EC. Within the same tissue, stable and activated ECs can be distinguished. The pathologic-like EC cluster, present exclusively in the HHT samples, may contribute to vascular leakage through the loss of important ligands involved in cellular communication.