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Results for “RNA tertiary structure”

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At least 19 recordsLinked to original sources

PubMed2025

A small cationic probe for accurate, punctate discovery of RNA tertiary structure.

RNA molecules fold into intricate three-dimensional tertiary structures that are central to their biological functions. Yet reliably discovering new motifs that form true tertiary interactions remains a major challenge. Here we show that RNA tertiary folding occasionally generates electronegative motifs that react selectively with the small, positively-charged probe trimethyloxonium (TMO). Sites with enhanced reactivity to TMO, compared with the neutral reagent dimethyl sulfate (DMS), are indicative of tertiary structure and define T-sites. These positions share a structural signature in which a reactive nucleobase is adjacent to non-bridging phosphate oxygens, creating localized regions of negative charge. T-sites consistently map to the cores of higher-order structural interactions and functional centers across diverse RNAs, including distinct states in conformational ensembles. In the 10,723-nt dengue virus genome, three strong T-sites were detected, each within a complex structure required for viral replication. Cation-based covalent chemistry enables high-confidence discovery and analysis of functional RNA tertiary motifs across long and complex RNAs, opening new opportunities for transcriptome-wide structural analysis.

RNA electrostatics↗

PubMed2001

Mutations of the protocadherin gene PCDH15 cause Usher syndrome type 1F.

Human chromosome 10q21-22 harbors USH1F in a region of conserved synteny to mouse chromosome 10. This region of mouse chromosome 10 contains Pcdh15, encoding a protocadherin gene that is mutated in ames waltzer and causes deafness and vestibular dysfunction. Here we report two mutations of protocadherin 15 (PCDH15) found in two families segregating Usher syndrome type 1F. A Northern blot probed with the PCDH15 cytoplasmic domain showed expression in the retina, consistent with its pathogenetic role in the retinitis pigmentosa associated with USH1F.

Aged↗

PubMed2002

A multigene family that interacts with the amino terminus of plasmodium MSP-1 identified using the yeast two-hybrid system.

Merozoite surface protein 1 (MSP-1) is a high-molecular-weight protein expressed on the surface of the malaria merozoite in a noncovalent complex with other protein molecules. MSP-1 undergoes a series of proteolytic processing events, but no precise biological role for the various proteolytic fragments of MSP-1 or for the additional proteins present in the complex is known. Through the use of the yeast two-hybrid system, we have isolated genes encoding proteins that interact with a region of the amino-terminal proteolytic fragment of MSP-1 from the mouse parasite Plasmodium yoelii. This analysis has led to the isolation of two sequence-related molecules, one of which is the P. yoelii homologue of MSP-7 originally described in Plasmodium falciparum. BLAST analysis of the P. falciparum database has revealed that there are six related protein molecules present in this species encoded near each other on chromosome 13. In P. falciparum, we designated these molecules MSRP-1 to -5. Analysis of the P. yoelii database indicates a similar chromosomal organization for the two genes in the mouse parasite species. The three P. falciparum sequences with the highest degree of homology to the P. yoelii sequences isolated in the two-hybrid screen have been characterized at the molecular level (MSRP-1 to -3). Expression analysis indicated that the mRNAs are expressed at various levels in the different asexual stages. Immunofluorescence studies colocalized the expression of the MSRP molecules and the amino-terminal portion of MSP-1 to the surfaces of trophozoites. In vitro binding experiments confirmed the interaction between MSRP-1, MSRP-2, and the amino-terminal region of P. falciparum MSP-1.

Amino Acid Sequence↗

PubMed2025

Improving RNA Secondary Structure Prediction Through Expanded Training Data.

In recent years, deep learning has revolutionized protein structure prediction, achieving remarkable speed and accuracy. RNA structure prediction, however, has lagged behind. Although several methods have shown some success in predicting RNA secondary and tertiary structures, none have reached the accuracy observed with contemporary protein models. The lack of success of these RNA structure prediction models has been proposed to be due to limited high-quality structural information that can be used as training data. To probe this proposed limitation, we developed a large and diverse dataset comprising paired RNA sequences and their corresponding secondary structures. We assess the utility of this enhanced dataset by retraining on a deep learning model, SincFold. We find that SincFold exhibited improved generalization to some previously unseen RNA families, enhancing its capability to predict accurate de novo RNA secondary structures. The RNASSTR dataset provides a substantial advance for RNA structure modeling, laying a strong foundation for the development of future RNA secondary structure prediction algorithms.

Journal Article↗

PubMed2005

Tissue specificity and regulation of the N-terminal diversity of reticulon 3.

Over the last few years, the widely distributed family of reticulons (RTNs) is receiving renewed interest because of the implication of RTN4/Nogo in neurite regeneration. Four genes were identified in mammals and are referred to as RTN1, 2, 3 and the neurite outgrowth inhibitor RTN4/Nogo. In the present paper, we describe the existence of five new isoforms of RTN3 that differ in their N-termini, and analysed their tissue distribution and expression in neurons. We redefined the structure of human and murine rtn3 genes, and identified two supplementary exons that may generate up to seven putative isoforms arising by alternative splicing or differential promoter usage. We confirmed the presence of five of these isoforms at the mRNA and protein levels, and showed their preferential expression in the central nervous system. We analysed rtn3 expression in the cerebellum further, and observed increased levels of several of the RTN3 isoforms during cerebellum development and during in vitro maturation of cerebellar granule cells. This pattern of expression paralleled that shown by RTN4/Nogo isoforms. Specifically, RTN3A1 expression was down-regulated upon cell death of cerebellar granule neurons triggered by potassium deprivation. Altogether, our results demonstrate that the rtn3 gene generates multiple isoforms varying in their N-termini, and that their expression is tightly regulated in neurons. These findings suggest that RTN3 isoforms may contribute, by as yet unknown mechanisms, to neuronal survival and plasticity.

Alternative Splicing↗

PubMed2026

Cleavage region organizes the structural architecture of the SINE-derived B2 repressive ribozyme.

The SINE-encoded B2 retrotransposon is an RNA Polymerase III (POL-III)-derived transcript whose expression is substantially upregulated during various cellular stress responses. Beyond retrotransposition, the B2 non-coding RNA can directly bind and repress the activity of RNA Polymerase II (POL-II), leading to a significant downregulation of transcripts during stress. Notably, our recent findings have shown that B2 is a self-cleaving ribozyme whose activity can be induced by interactions with chromatin-modifying factors through non-canonical epigenetic mechanisms that co-regulate its function across distinct chromatin-binding target loci. Here, by integrating RNA chemical probing, small-angle X-ray scattering, and 3D motif modeling, we determine structural ensemble-to-function relations for the B2 SINE ribozyme RNA. Genetic perturbations of the RNA suggest that the B2 SINE ribozyme has a well-defined secondary and dynamic tertiary structure that depends on the integrity of the critical region, which confers ribozymatic activity and repressive extent by POL-II. Using an RNA engineering approach, we examine the effects of point mutations, deletions of the main cleavage site, and deletions of the cleavage domain on the structural ensemble of the RNA. Combining this approach with in vitro and in vivo functional perturbation methods highlights the relationships between structural ensembles and various biologically relevant functional outcomes.

RNA, Catalytic↗

PubMed2025

Enzymes in high-throughput RNA sequencing: Applications and challenges.

High-throughput RNA sequencing provides genome-wide information on the dynamics of RNA in each cell and how the dynamics responds to environmental changes. Next-generation sequencing by the Illumina platform currently provides the highest information output as compared to other platforms. A key component of next generation sequencing of each RNA is the successful end-to-end reverse-transcription into a cDNA strand. This can be highly challenging given the propensity of each RNA to adopt ordered structures and to contain post-transcriptional modifications. While many reverse transcriptase (RT) enzymes have been developed over the years to maximize read-through of an RNA, their processivity and efficiency varies, raising the question of how to select the RT for the experiment at hand. Here, we use tRNA as a model for genome-wide sequencing, as tRNA has a stable secondary and tertiary structure and has a high density and wide variety of post-transcriptional modifications, presenting one of the most challenging problems of sequencing RNA. We compare the efficiency of end-to-end cDNA synthesis of tRNA among several recent RT enzymes and provide a general sequencing workflow that is applicable to most of these enzymes.

High-Throughput Nucleotide Sequencing↗

PubMed2026

tRNA methylation: functional insights and epitranscriptomic regulation.

tRNAs, one of the most conserved and abundant RNAs, are central components of protein synthesis, transferring genetic information from DNA to proteins through a precise base-pairing mechanism. Post-transcriptional modifications of tRNAs by tRNA modifying enzymes are essential for maintaining their normal physiological functions, including methylation, isomerization and glycosylation. tRNA methylation, particularly 1-methyladenosine (m1A), 5-methylcytidine (m5C), and 7-methylguanosine (m7G), are among the most abundant and diverse types of post-transcriptional modifications of tRNA, which promote the stability of tRNA secondary and tertiary structures and allow for proper translation. In addition, tRNA methylation affects the production and function of tsRNA (tRNA-derived small RNA), small fragments of RNA that further regulate gene expression and protein synthesis. In our review, we discuss the relevant biological functions of tRNA methylation, including tRNA stability, protein translation, and tsRNA biogenesis.

RNA, Transfer↗

PubMed2026

Effect of Tertiary Lymphoid Structures on Immune Cell Infiltration in the Tumor Microenvironment and Prognosis in Lung Adenocarcinoma.

Tertiary lymphoid structures (TLSs) modulate immune responses in various solid tumors, but their comprehensive role in lung adenocarcinoma (LUAD) remains unclear. In this study, we analyzed RNA-seq data from 539 LUAD patients in The Cancer Genome Atlas (TCGA) and microarray data from 223 samples from the Gene Expression Omnibus (GEO, GSE13213, and GSE37745). TLS signatures were evaluated via unsupervised consensus clustering based on 12 chemokine transcriptome signatures. The relationships between TLS and clinical characteristics, tumor microenvironment (TME) cell infiltration, and prognosis were assessed using ESTIMATE and CIBERSORT. A prognostic model was established using LASSO regression and validated with external datasets. Additionally, H&E and IHC analyses were performed to explore associations between intratumoral TLS density, immune-related molecular expression, and patient prognosis in LUAD. Consensus clustering of the TCGA cohort revealed two distinct LUAD patient clusters according to TLS abundance. Cluster 1 exhibited greater immune cell infiltration, more favorable prognosis, and increased expression of immune checkpoint molecules. We developed a prognostic model comprising eight survival-associated genes that act as independent prognostic factors for patient survival. H&E/IHC analyses revealed that TLS density-regardless of pathological stage-was associated with better prognosis; higher intratumoral TLS density/proportion was also related to more favorable outcomes. IHC confirmed that survival-associated genes (CD5, HLA-DMB, and P2RY13) are independent prognostic indicators in LUAD. Our study demonstrated the close relationship between TLS signatures and an active immune microenvironment, highlighting their potential as independent prognostic indicators in LUAD.

Humans↗

PubMed2026

Refining a giant virus lineage: a novel order unifying Mamonoviridae and "Manesviridae," unveiled by the discovery of furtivovirus.

UNLABELLED: The evolutionary origins and taxonomic framework of giant viruses related to the family Mamonoviridae and its relative group, including clandestinovirus, remain unclassified due to gaps in genome size and host range between these two groups. This study aimed to address this gap by integrating our newly isolated virus with publicly available metagenome-assembled genomes (MAGs) to construct a more robust phylogenetic framework. Here, we report the isolation and characterization of a new giant virus, furtivovirus, using the unicellular amoeba Vermamoeba vermiformis as a host. Furtivovirus has a genome of approximately 560 kbp and shares key features with its closest relative, clandestinovirus. Ultrastructural analysis revealed a unique host-nucleus-dependent replication strategy characterized by the breakdown of the nuclear membrane and the packaging of nascent virions directly within the nucleoplasm, distinguishing it from canonical cytoplasmic virion factories. Comprehensive phylogenetic and comparative genomic analyses of shared orthologous groups and nucleocytovirus marker proteins revealed that furtivovirus, clandestinovirus, ushikuvirus, and usurpativirus form a distinct monophyletic clade, for which we propose a new family, "Manesviridae." Further analysis using amino acid-based similarity metrics of Nucleocytoviricota viral genomes, including established MAGs, demonstrated that this new family is robustly placed as a sister group to the family Mamonoviridae. This study elucidated the evolutionary relationships between viruses with large and small genomes that possess similar virion sizes within this lineage. Based on this cumulative evidence, we propose the establishment of a new order to unify these two families, thereby expanding their diversity and clarifying the evolutionary history of this branch within Nucleocytoviricota. IMPORTANCE: Giant viruses challenge our traditional understanding of viral evolution, raising the question of how a single related group can diverge to infect different hosts while evolving into vastly different genome sizes and replication strategies. The family Mamonoviridae and its relatives epitomize this evolutionary divergence: one group possesses massive genomes, whereas the other has genomes that are less than half their size. The discovery of furtivovirus and its unique nucleoplasm-dependent replication cycle provides a critical biological context for this genomic disparity. Through deep comparative genomic analysis, we demonstrated that these seemingly disparate lineages share a cohesive evolutionary origin that is distinct from other established orders. This finding highlights the complexity of genome evolution, demonstrating that giant viruses can expand their overall genome size to adapt to uncertain environments while reducing their core essential genes, thereby providing new insights into the evolutionary pressures that shape the diversity of the virosphere.

Giant Viruses↗

PubMed2025

Deciphering the Impact of Temperature on Pleiotropic Consequences of RNA Polymerase Mutations.

Despite occurring in an essential molecule, mutations in RNA polymerase readily emerge and elicit complex pleiotropic effects across different levels of biological organization, which are all modulated by environment. We investigated the impact of temperature on the effects of six mutations on sequence, structure, transcriptome, and organismal traits. We found temperature altered the transcriptomic response and key organismal traits such as growth rate and biofilm formation in a genotype-specific manner. Critically, mechanistic insights into the possible drivers of mutational effects emerged only when examining the relationships between different levels of organization: location of mutations in the tertiary structure and distance to key interacting molecules partly explained the observed transcriptomic differences, which in turn drove the impact of mutations on organismal traits. While falling short of capturing the full complexity of the system, our findings underscore the benefits of integrating insights across multiple biological levels to understand the relationship between environment and mutational effects in molecules with extensive pleiotropic effects.

Mutation↗

PubMed2026

Integrated analysis of ATAC-seq and RNA-seq reveals the TCP-ARF molecular module related to pathogenic process of phytoplasma infection in Paulownia fortunei.

BACKGROUND: Witches’ broom is an important disease of the Paulownia fortunei. Understanding the pathogenesis of witches’ broom is a prerequisite for its prevention and control. Phytoplasma is the pathogen of Paulownia witches’ broom. RESULTS: We investigated the changes in chromatin accessibility before and after phytoplasma infection in Paulownia fortunei by analyzing the DNA accessibility (ATAC-seq). In phytoplasma-infected P. fortunei (PFI) compared to healthy samples (PF), the closed regions of chromatin(1187 regions) were three times more than the open regions (352 regions). Fifty one percent of the accessible chromatin regions were overlapped with either H3K27ac or H3K9ac peaks. The closed regions were enriched in the conserved motif TGGGC[CT] that is recognized by the TCP transcription factor family. The closed regions in PFI are intersected with ARF family gene locus. The gene PfARF3 was verified to interact with the PfTCP23 transcription factor. The PfTCP23 was predicted to be interacted with the effector pawb44 in the pathogen of phytoplasma. CONCLUSIONS: The phytoplasma infection in P. fortunei is involved in the chromatin changes of the DNA accessibility and histone modification. The binding regions of TCP23 were found to be changed mostly in the accessibility between PFI and PF. The TCP-ARF module was found to be the possible regulatory module inducing the crinkled leaf trait.

RNA-Seq↗

PubMed2026

Spatiotemporal mapping of tertiary lymphoid structure heterogeneity shapes immune niches and clinical outcomes in intrahepatic cholangiocarcinoma.

Intrahepatic cholangiocarcinoma (iCCA) is a highly lethal malignancy with limited therapeutic options. The spatial architecture and functional diversity of tertiary lymphoid structures (TLSs) in iCCA remain unclear. Here, we present a multimodal spatial atlas of TLSs and identified intratumoral TLSs (iTLSs) as independent prognostic markers. Bulk proteomic profiling of 214 discovery and 155 validation cases identified a four-tier TLS-based tumor microenvironment classification system and supported development of a TLS-predictive random forest classifier. Imaging mass cytometry revealed that iTLS+ tumors harbor structured immune architectures, where M1-like tissue-resident macrophages (RTMs), dendritic cells, and CXCL13+ CD4+ T cells colocalize to form antigen-presenting neighborhoods (apc-CNs) spatially coupled to TLS core regions (TLScore-CNs). Single-cell spatial transcriptomics further resolved 61 TLSs into 14 spatial niches and defined a pseudotemporal maturation continuum: aggregated, activated, and postactivated. Intraniche communication, primarily mediated by ifnCAFs, iCAFs, and CXCL12+ macrophages, evolved dynamically with maturation. Single-nucleus RNA sequencing combined with Tangram-based spatial mapping revealed CXCL12+ macrophages and iCAFs forming a peripheral band in aggregated TLSs, whereas ifnCAFs infiltrated TLS interiors during activation. These findings define TLS heterogeneity and provide insights for stroma-directed immunotherapy.

Cholangiocarcinoma↗

PubMed2019

Decrypting noncoding RNA interactions, structures, and functional networks.

The world of noncoding RNAs (ncRNAs) is composed of an enormous and growing number of transcripts, ranging in length from tens of bases to tens of kilobases, involved in all biological processes and altered in expression and/or function in many types of human disorders. The premise of this review is the concept that ncRNAs, like many large proteins, have a multidomain architecture that organizes them spatially and functionally. As ncRNAs are beginning to be imprecisely classified into functional families, we review here how their structural properties might inform their functions with focus on structural architecture-function relationships. We will describe the properties of "interactor elements" (IEs) involved in direct physical interaction with nucleic acids, proteins, or lipids and of "structural elements" (SEs) directing their wiring within the "ncRNA interactor networks" through the emergence of secondary and/or tertiary structures. We suggest that spectrums of "letters" (ncRNA elements) are assembled into "words" (ncRNA domains) that are further organized into "phrases" (complete ncRNA structures) with functional meaning (signaling output) through complex "sentences" (the ncRNA interactor networks). This semiotic analogy can guide the exploitation of ncRNAs as new therapeutic targets through the development of IE-blockers and/or SE-lockers that will change the interactor partners' spectrum of proteins, RNAs, DNAs, or lipids and consequently influence disease phenotypes.

DNA↗

PubMed2026

A structural bridge between dengue virus tandem xrRNAs facilitates coordination of exonuclease resistance.

Orthoflavivirus RNA genomes resist host 5'-3' exoribonucleases to produce subgenomic flaviviral RNAs (sfRNAs). This resistance is conferred by exoribonuclease-resistant RNA (xrRNA) structures within the viral 3' untranslated region that often occur in tandem, and whose function can be coupled. In dengue virus serotype 2 (DENV2), this coupling results in changing patterns of sfRNA identity and abundance associated with the ability of the virus to adapt to host vs. vector infections. The physical basis of this coupling was unknown. Using a combination of virology, biochemistry, bioinformatics, structural biology, and biophysics, we explored the structural and sequence determinants of tandem xrRNA coupling in DENV2. We discovered that the spatial proximity, order, and structural integrity of the tandem xrRNAs are all important for coupling. Furthermore, an unpaired A-rich linker that lies between the two xrRNAs is essential in stabilizing a specific structure that correlates to coupling. This A-rich sequence likely forms tertiary contacts with an adjacent stem-loop structure to form a physical bridge between the two xrRNAs, a finding that is supported by a mid-resolution cryo-electron microscopy (cryo-EM) map of the DENV2 tandem xrRNAs. Disruption of the structure of this bridge by mutation changes the relative orientation or spacing between the tandem xrRNAs, which is correlated to their functional coupling. These findings help provide an explanation for the coupling between tandem xrRNAs, suggesting a new mechanistic hypothesis in which the two tandem xrRNAs can simultaneously encounter Xrn1.IMPORTANCEDengue virus (DENV) generates non-coding subgenomic flaviviral RNAs (sfRNAs) that affect several cellular pathways and are important for successful infection. These sfRNAs are formed by structured RNA elements in the viral genome called exoribonuclease-resistant RNAs (xrRNAs), which fold into a distinct three-dimensional topology to block degradation by host cell exoribonucleases and often occur in tandem. Specific patterns of sfRNAs made during infection are important for host vs. vector fitness, and in DENV2, this pattern depends on functional coupling between tandem xrRNAs. However, the source of this functional coupling was unknown. We determined that an unpaired A-rich linker between the tandem xrRNAs is necessary for creating a structural bridge between the tandem xrRNAs. This bridge appears to favor a specific orientation between the tandem xrRNAs that is correlated to coupling and therefore to the patterns and relative abundance of sfRNAs produced during infection.

Dengue Virus↗

PubMed2026

Spatial habitat radiomics predicts tertiary lymphoid structure status and identifies an IDO1+ migratory dendritic cell axis in breast cancer.

BACKGROUND: Tertiary lymphoid structures (TLS) are spatially organized immune niches associated with therapeutic response and favorable outcomes in breast cancer (BC). However, TLS assessment currently relies on invasive tissue-based analyses, and the biological mechanisms underlying imaging-based TLS prediction remain poorly understood. METHODS: We developed and validated a spatial heterogeneity-based radiomic TLS signature (shTLS) using dynamic contrast-enhanced MRI to non-invasively predict TLS status across multicenter BC cohorts. Spatial habitat radiomics were used to capture intratumoral and peritumoral immune-related heterogeneity. Integrated multi-omics analyses, including transcriptomics, pathomics, genomics, single-cell RNA sequencing, immunohistochemistry, and multiplex immunofluorescence, were performed to biologically interpret shTLS-defined subgroups. Functional drug-sensitivity assays were conducted to assess therapeutic implications. RESULTS: The shTLS model achieved robust predictive performance across independent cohorts and molecular subtypes. High shTLS scores were associated with immune-inflamed tumors characterized by spatially clustered activated T cells and dendritic cells (DCs). In contrast, shTLS-low tumors exhibited an immunosuppressive spatial niche with peripheral accumulation of CD4+ PD-1+ T cells and plasma cells, increased immune-tumor separation, and enhanced inflammatory and immunoregulatory signaling. An indoleamine 2,3-dioxygenase 1 (IDO1)-associated immunoregulatory program was observed in the shTLS-low tumors, which appeared to be preferentially expressed by LAMP3+CCR7+ migratory DCs. Pharmacologic inhibition of IDO1 enhanced chemotherapy and CDK4/6 inhibitor sensitivity in vitro. CONCLUSION: This study establishes spatial radiomics as a non-invasive approach to decode TLS-associated immune ecosystems and supports the presence of an IDO1-associated immunosuppressive phenotype, providing biological insight and translational rationale for patient stratification and future combination strategies.

Humans↗

PubMed2025

Structural basis for the function of long noncoding RNA Pnky in neural stem cells.

LncRNA Pnky is a trans-acting regulator of neural stem cell (NSC) differentiation, but the molecular mechanisms by which Pnky regulates neurogenesis is unknown. A fundamental step towards mechanistic understanding is to determine whether a lncRNA has folded structure that underlies biological function. Using chemical probing and high-throughput analysis, we determined the secondary structure of Pnky folded in vitro and in cellulo. Pnky adopts a compact structure in vitro with distinct modules and evidence of tertiary interactions. In cellulo, Pnky structure is remarkably similar to the in vitro conformation. We used locked nucleic acid oligonucleotides to interrogate the entire Pnky transcript for function in NSCs and identified regions that when targeted increased neurogenesis - phenocopying Pnky knockdown - without decreasing transcript abundance. Our findings provide a structural basis for the role of Pnky in neurogenesis and, more broadly, illustrate how structural maps combined with phenotypic data can advance fundamental understanding of lncRNA mechanism.

LNA-ASOs↗

PubMed2026

Molecular and Immune Landscape of Recurrent and/or Distant Metastatic Squamous Cell Carcinoma of the Head and Neck: An EORTC/IMMUCAN Project.

PURPOSE: Recurrent and/or metastatic (R/M) squamous cell carcinoma of the head and neck (SCCHN) is a heterogeneous clinical entity with a poor prognosis. The molecular and immune landscape of R/M SCCHN is underexplored. To offer a comprehensive view of the tumor microenvironment and molecular profile of R/M SCCHN, we performed an in-depth molecular and immune characterization, evaluating the impact of human papillomavirus (HPV) status, tobacco and alcohol history, primary tumor site, relapse pattern, and treatment history at the genomic, transcriptomic, and immune levels. EXPERIMENTAL DESIGN: We analyzed 253 R/M SCCHN fresh tumor biopsies from the IMMUcan project using RNA sequencing (RNA-seq), whole-exome sequencing, and multiplex immunofluorescence (mIF). RESULTS: The primary clinical factor affecting the immune microenvironment was the number of treatment lines, with significant declines in T cells and B cells observed via mIF and RNA-seq as the number of R/M treatment lines progressed. IL6, IL13, IL15, and NRF2 pathways were enriched in HPV-negative R/M SCCHN compared with HPV-positive tumors, whereas no immune differences were detected between these two clinical groups. Specific genomic alterations were observed in laryngeal cancer (DDR2, FOXP1, KLF5, and ROBO2), whereas nonsmokers/nondrinkers exhibited alterations in SPEN, PBRM1, and CYLD. 11q13.3 amplification was linked to HPV-negative metastatic tumors and hypopharyngeal cancer. HPV-negative SCCHN with locoregional recurrence showed elevated EGFR and CXCL12 pathway activity. Partial epithelial-mesenchymal transition transcriptomic signatures correlated with poor survival, whereas lymphocyte infiltration, especially in the context of tertiary lymphoid structures, was associated with improved survival. CONCLUSIONS: Our study highlights key molecular and immune differences across R/M SCCHN subgroups, identifies potential biomarkers, and suggests biological rationales for tailored therapeutic strategies.

Humans↗