PubMed HealthSearch

SEARCH · PubMed Health

Results for “Genome Maintenance”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

The function of Mgs1/WRNIP1 in genome maintenance.

Preservation of genomic integrity during replication is challenging, because replication forks are often stalled by several forms of DNA damage or stable secondary DNA structures. Prolonged stalling of the replication fork can lead to incomplete replication, which may induce double strand breaks, genome rearrangements and cell death. Therefore, several DNA repair mechanisms evolved to rescue stalled replication forks, which can elaborate in error-free or error-prone manners. The pathway selection and the fine tuning of the collaboration between different DNA repair proteins involved in the rescue of the stalled replication fork are very important. Based on our recent knowledge, yeast Mgs1 and its human homologue WRNIP1 proteins can be excellent candidates for this fine-tuning regulator function. In this review we summarize our current knowledge about them and try to point out the most important future steps to prove this hypothesis.

DNA repair

Distinct functions of mammalian RAD51 paralogs in genome maintenance.

RAD51 paralogs (RAD51B, RAD51C, RAD51D, XRCC2, and XRCC3) are evolutionarily conserved essential proteins for cell survival and genome maintenance. RAD51 paralogs were originally identified to play a role in homologous recombination-mediated repair of DNA double-strand breaks (DSBs). However, investigations over the last decade have uncovered new roles of RAD51 paralogs beyond DSB repair in replication stress responses, including replication fork progression, fork stability, and its restart. Recent structural studies have not only uncovered the molecular architecture of previously known RAD51 paralog complexes but also identified novel paralog complex assemblies, providing mechanistic insights into their various genome-maintenance functions. Additionally, a role for RAD51 paralogs in resolving R-loops has been identified, and studies with cancer-associated variants suggest that RAD51 paralogs are potential determinants of cancer susceptibility and therapeutic responses. In the present review, we highlight the recently deciphered structures and novel functions of RAD51 paralog complexes and discuss the clinical and therapeutic implications.

Rad51 Recombinase

Folding a broken genome: the versatile roles of cohesin in genome maintenance.

Cohesin is a protein complex that shapes 3D genome organization through two distinct mechanisms. First, cohesin tethers replicated chromatids from DNA replication until mitosis. This process, known as sister chromatid cohesion, ensures accurate chromosome segregation and enables high-fidelity DNA repair through homologous recombination between the sister chromatids. Second, cohesin organizes the genome during interphase by dynamically extruding chromatin loops, structures that have key roles in gene regulation. Recent work has shown that, in addition to the well-established repair functions of sister chromatid cohesion, cohesin-mediated chromatin looping is closely linked to the repair of DNA double-strand breaks - one of the most toxic DNA lesions. In this Review, we discuss the central roles of cohesin in maintaining genome stability, with emphasis on the cellular response to DNA double-strand breaks. We review how dynamic loop structures facilitate signalling of repair events and promote long-range chromatin motions that underpin the repair process. Overall, its dual mode of action - cohesion and loop extrusion - positions cohesin as a central regulator of chromatin architecture and genome maintenance.

Cohesins

DNA polymerase I: structure, activity, and function in bacterial DNA replication and repair.

Faithful replication and repair of the genome are essential processes for all life. Genome maintenance is coordinated by a complex suite of proteins, with bacteria evolving intricate systems despite their relatively simplistic genomes. DNA polymerases are a key class of proteins that mediate genome maintenance. DNA polymerases are all capable of extending nascent strands of DNA but contribute to DNA replication and repair in distinct ways depending on their active site and substrate specificity. The first discovered polymerase, bacterial DNA polymerase I (Pol I), has long been considered the primary enzyme responsible for Okazaki fragment maturation and resynthesis in many DNA repair pathways. These conclusions derive primarily from studies using the gram-negative bacterium, Escherichia coli. Given that some bacterial lineages diverged from E. coli over a billion years ago, these assumptions may not account for evolution in functional diversity. In this review, we examine the structural features of bacterial Pol I and discuss how each of its distinct enzymatic activities contribute to genome maintenance. Throughout, we introduce differences that have been discovered between gram-negative and gram-positive species and explore how activity differences may translate to functional adaptations in replication or repair. We focus on evidence from gram-positive bacteria, particularly Bacillus subtilis and Geobacillus stearothermophilus, that challenges the universality of Pol I's functions and reveals lineage-specific adaptations in replication and repair mechanisms. By synthesizing historical perspectives with recent discoveries, this review underscores both the importance of Pol I and the evolutionary diversification of Pol I in bacterial DNA metabolism.

Bacterial DNA replication

Loss of maternal PADI6 disrupts DNA methylation and genomic imprinting maintenance in late preimplantation mouse embryos.

BACKGROUND: The maternal-effect protein PADI6, which is part of the subcortical maternal complex, is involved in proper spindle assembly, organelle distribution, ribosome storage, and cytoplasmic lattice organization in mouse oocytes. In humans, variants of PADI6 are associated with female infertility and multilocus imprinting disturbance in offspring. Recently, it was demonstrated that PADI6 plays a role in the storage and cytoplasmic localization of epigenetic factors, including UHRF1 and DNMT1. Moreover, maternal PADI6 depletion leads to defective epigenetic reprogramming and zygotic genome activation but not to an imprinting defect in two-cell mouse embryos. These findings raise the possibility that imprinting disturbances arise later in development. RESULTS: By employing combined single-blastocyst RNA-seq/BS-seq and immunostaining validation in the embryos derived from Padi6P620A-mutant oocytes, we investigated the role of Padi6 in late preimplantation development. We demonstrated that embryos that overcame the two-cell stage block had a dramatic reduction in UHRF1 and DNMT1 protein levels, a decrease in H3K9me3, and whole-genome hypomethylation, including most imprinted loci and repetitive elements, at the blastocyst stage. Furthermore, these maternal mutant embryos showed deregulation of inner cell mass markers and defective blastocyst implantation, but no effect on trophoblast differentiation. CONCLUSION: Our results demonstrate that maternal PADI6 is a key regulator of the stability of epigenetic factors required to maintain repressive marks in late preimplantation mouse embryos. Its deficiency results in genomic imprinting defects that closely resemble those found in human patients and provide a mechanistic explanation for MLID caused by maternal PADI6 variants. Furthermore, the impairment of blastocyst implantation capacity, likely due to dysregulation of inner cell mass differentiation, provides new mechanistic insights into the control of female fertility and embryo development exerted by PADI6.

DNA Methylation

Protein persulfidation emerges as a conserved component of the redox response to DNA damage.

Genotoxic stress is frequently accompanied by alterations in cellular redox homeostasis; however, the mechanisms linking redox regulation to the DNA damage response (DDR) remain incompletely understood. Here, we investigated the early redox response to DNA damage induced by methyl methanesulfonate (MMS) in Saccharomyces cerevisiae, focusing on cysteine oxidative post-translational modifications (PTM). We show that activation of the DNA damage response is accompanied by rapid redox changes that occur in the absence of a generalized oxidative stress response. MMS exposure promotes selective remodeling of cysteine oxidative modifications, characterized by decreased free thiols, robust induction of protein persulfidation, and comparatively modest changes in sulfenylation. These alterations are accompanied by increased intracellular hydrogen sulfide levels, supporting the involvement of reactive sulfur species in the cellular response to DNA damage. Proteome-wide analyses revealed that cysteine oxidative modifications preferentially target proteins involved in central metabolism, nucleotide biosynthesis, and genome maintenance. Consistent with these observations, MMS-induced genotoxic stress promotes metabolic adaptation characterized by increased mitochondrial respiration, elevated ATP production, and mitochondrial morphological remodeling, linking bioenergetic adaptation to redox regulation. Importantly, perturbation of intracellular redox balance using N-acetylcysteine compromises survival under DNA-damaging conditions, supporting a functional role for redox signaling during the DDR. Finally, MMS treatment also induces protein persulfidation in mammalian cells. Moreover, exposure to etoposide, a mechanistically distinct genotoxic agent that induces DNA double-strand breaks through topoisomerase II inhibition, showed a similar trend, suggesting that protein persulfidation may not be restricted to alkylation-induced DNA damage. Together our findings identify protein persulfidation as a prominent component of the redox response to DNA damage and provide new insight into the functional interplay between mitochondrial metabolism, cysteine-based redox regulation, and genome maintenance.

Oxidation-Reduction

Efficiency of DNA repair mechanisms of domestic dog primary fibroblasts isolated from small and large breeds of different ages in response to double stranded breaks (DSB).

Aging is associated with increased genomic instability, a phenomenon largely driven by the accumulation of DNA damage over time, and large species of mammals seem to have more robust DNA repair systems associated with longer lives. Among DNA lesions, double-strand breaks (DSBs) are particularly deleterious and have been implicated in age-related functional decline and disease. In this study, we investigated how age and body mass affect the efficiency of DSB repair (DSBr) in primary fibroblast cells isolated from domestic dogs, a species that exhibits significant intraspecies variation in lifespan and body mass. Primary fibroblast cells were isolated from puppies and senior dogs of both large and small breeds. Cells were treated with 100 µM etoposide to induce DSBs and subsequently analyzed at two post-treatment recovery intervals (2 and 24 h) to correlated with the two pathways associated with DSBr, the fast, non-homologous end joining (NHEJ) and the much slower, homologous recombination (HR). Cells were stained for γ-H2AX foci and images were collected using confocal microscopy. We found that mean fluorescence per cell was higher in older dogs of both size classes in the 2 h recovery, indicating higher amounts of DNA damage but suggesting similar efficiencies through the NHEJ repair mechanism in older dogs despite size class. We also show that mean fluorescence per cell was higher in the older large breed dogs in the 24 h recovery, suggesting that the slower phase associated with HR seems to be deficient in cells from older, larger breeds of dogs. These findings support the broader theory that aging is associated with impaired genomic maintenance and establish domestic dogs as a valuable model for studying the cellular mechanisms of age-related genomic instability.

Animals

Integrative Genomic and Transcriptomic Insights into High-Altitude Adaptation in Changthangi Goats.

The Changthangi goat, native to the high-altitude Ladakh Plateau in northern India, thrives in oxygen-deficient environments above 4,000 m. This study investigated the genetic basis of high-altitude adaptation in Changthangi goats by integrating comparative genomics and transcriptomics, using the tropical lowland Jamunapari goat as a comparative model. Whole-genome sequence data from 15 individuals per breed were analyzed using complementary selection sweep metrics, including nucleotide diversity, Tajima's D, iHS, CLR, XP-EHH, and FST. These analyses identified candidate genomic regions under strong selective pressure, encompassing genes involved in hypoxia sensing (HIF-1α, HIF-2α/EPAS1, EGLN1), angiogenesis (VEGFA, AGGF1, ZEB1), cardiovascular regulation (PRKCB, ESR1, RYR2), mitochondrial and energy metabolism (ACADSB, ACSS3, ACSL1), cellular stress tolerance (BCL2, ATM), and thermogenesis (UCP1, FGF21). Unlike previous caprine studies that primarily infer hypoxia adaptation from genomic signals alone, our study integrates cardiac transcriptomics to demonstrate that genomic selection in Changthangi goats is accompanied by coordinated transcriptional remodeling across interconnected physiological systems in a physiologically relevant tissue. Comparative cardiac transcriptomic profiling revealed concordant expression divergence in genes associated with oxygen transport, vascular remodeling, mitochondrial function, substrate utilization, redox balance, and genome maintenance. This integrative multi-omics framework provides a mechanistic view of caprine high-altitude adaptation and highlights the value of combining genomic selection analyses with tissue-specific transcriptional profiling to resolve complex adaptive traits.

Animals

Donor transcription suppresses D-loops in cis and promotes genome stability.

DNA is a substrate for competing protein-mediated activities. Whether and how transcription and the synaptic steps of recombination collide or are coordinated has not been investigated. Here, using a controlled break induction system and physical detection of D-loop DNA joint molecules in S. cerevisiae, we show that donor transcription by RNA polymerase II strongly and acutely suppresses D-loops in cis. The extent of this suppression depends on the orientation of transcription, suggesting the preferential usage of one end for the repair of DNA break in transcribed regions. Transcription-mediated D-loop suppression does not rely on endogenous transcription factors, the RNA product, or RNA:DNA hybrids. It is independent of, and can be more potent than the conserved trans D-loop-disruption factors Sgs1-Top3-Rmi1BLM-TOPO3α-RMI1/2, Mph1FANCM, and Srs2. This transcription-mediated control promotes genome maintenance by inhibiting ectopic recombination and multi-invasion-induced rearrangements, while authorizing allelic inter-homolog repair. These findings reveal the prioritization between two universal DNA-dependent processes and its role in promoting genome stability.

Genomic Instability

Integrative modeling of the genome structure and dynamics in fission yeast.

Genome organization in the nucleus is highly structured and dynamic. Recent advances in genomic technology have enabled the measurement of genome-wide architecture and locus-specific motion, yielding contact maps and live-cell trajectories. However, these outcomes are derived from different modalities and are not directly comparable, with their quantitative integration being a key challenge. Here we establish a genome-wide live-cell imaging platform in fission yeast Schizosaccharomyces pombe, tracking 131 chromosomal loci, along with the spindle pole body (SPB) and nucleolus, to construct a quantitative map of locus dynamics. By integrating these dynamics with contact data through polymer modeling of Hi-C data, we build a physics-based "digital twin" of the S. pombe genome consistent with the spatiotemporal dynamics of interphase chromatin. We validate it against genome-wide mobility patterns and known architectural features, including centromere and telomere clustering. The model also identifies distinct dynamical regimes: centromere- and telomere-proximal loci relax within [Formula: see text]150 s, whereas the remaining loci relax within [Formula: see text]70 s. We measure semiperiodic dynamics of SPB motion, including a characteristic peak near 225 s and [Formula: see text] fluctuations. We use the model with SPB-directed forcing to show how these low-frequency components propagate through the genome to drive genome-wide chromatin displacements. Together, this predictive physics-based modeling framework integrates genome structure and dynamics to reveal how nuclear mechanical driving forces shape chromosome motion, linking mechanically driven chromatin responses to genome maintenance and regulation.

Schizosaccharomyces

Mitochondrial Haplotype Shapes the Trajectory of Ovarian Aging in Genetically Heterogeneous Rats.

Ovarian aging leads to permanent reproductive senescence and systemic hormonal changes that predispose women to age-associated comorbidities. Despite these observations, the intrinsic mechanisms driving age-related ovarian decline are poorly defined. Mitochondrial DNA (mtDNA) mutations and instability are strongly associated with aging; however, it remains unknown if naturally occurring mitochondrial genetic variation influences the trajectory of ovarian aging. To address this, we compared two genetically heterogeneous rat cohorts (OKC-HETB and OKC-HETW) that differ in mitochondrial haplotype on a randomized but equivalently distributed nuclear background. The OKC-HETW haplotype was associated with accelerated loss of primordial follicles and pathological remodeling marked by fibrosis, macrophage infiltration, and multinucleated giant cells. These tissue-level pathologies were paralleled by mitochondrial dysfunction, characterized by decreased respiratory complex activity, ATP production, and mtDNA copy number. Mechanistically, we identified a haplotype-specific defect in mitochondrial genome maintenance. Although TFAM expression was normal, and total TFAM protein was elevated, OKC-HETW ovaries showed reduced mitochondrial TFAM abundance, TFAM-mtDNA binding, and TOMM20, suggesting that impaired TOMM20-mediated import is associated with compromised mitochondrial genomic stability. Longitudinal transcriptomic and proteomic analyses further indicate that mitochondrial haplotype influences the rate of ovarian aging, with OKC-HETW ovaries showing accelerated activation of inflammatory and fibrotic pathways alongside suppressed proteostasis and mitochondrial function. These defects corresponded to impairments in ovulation and a trend toward worsening oocyte quality. Collectively, our findings identify mitochondrial haplotype as a heritable modifier of ovarian aging rate that acts in concert with the nuclear genome, and a putative target for preserving ovarian function and female healthspan.

Animals

Differentiation-independent Activation of HPV Genome Replication by the lncRNA DINO.

Human papillomaviruses (HPV) rely on multiple host cell factors to replicate the viral genome, yet the contribution of host long noncoding RNAs (lncRNAs) to viral genome maintenance and amplification in the productive life cycle remains poorly understood. In this study, we show that the lncRNA DINO is a driver of HPV DNA replication. DINO levels increase during keratinocyte differentiation and ectopic expression of DINO promotes both HPV genome replication and the formation of replication foci, and this is independent of keratinocyte differentiation signals. Ectopic DINO expression increases select early viral transcript levels including E1^4, E1, and E2. Notably, DINO's subcellular localization is also context-dependent: during DNA damage DINO is predominantly cytoplasmic, but during keratinocyte differentiation nuclear retention is observed. This differential localization suggests that DINO has distinct functional roles in keratinocyte differentiation and HPV biology. Our findings highlight DINO as a lncRNA that promotes HPV genome replication and suggest that lncRNAs may play underappreciated roles in host-virus interactions. This work provides a foundation for further exploration of lncRNAs as potential therapeutic targets in HPV-associated diseases.

Journal Article

Maternal age as a driver of genome instability: mechanisms linking aneuploidy, mutagenesis and mitochondrial dysfunction.

Advanced maternal age is a well-established risk factor for adverse reproductive outcomes due to increased rates of aneuploidy. However, emerging evidence indicates that the genetic consequences of maternal aging extend well beyond chromosome mis-segregation. Aging oocytes acquire a broad spectrum of genetic abnormalities, including maternally derived nuclear de novo mutations (DNMs) and mitochondrial DNA mutations, together with epigenetic dysregulation of DNA methylation and post-translational modification levels. These changes reflect the unique biology of the female germline in which oocytes remain arrested in meiotic prophase I for decades. Age-related deterioration of key processes, such as erosion of cohesion complexes, altered meiotic recombination, and weakened spindle assembly checkpoint surveillance collectively destabilize meiotic chromosome architecture, directly driving chromosome mis-segregation. At the same time, accumulation of endogenous DNA damage and declining DNA damage and repair processes increase the chances of transmitting lesions that can be converted into sequence-level mutations during the earliest embryonic divisions, when genome maintenance relies exclusively on maternal factors. High-resolution sequencing studies further demonstrate that maternal aging is associated with increased DNMs burden in both nuclear and mitochondrial DNA. Together, these findings support a model in which maternal aging is a driver of genome-wide instability that links aneuploidy and mutagenesis through shared defects in meiotic surveillance, declining DNA repair efficiency, and mitochondrial function. This framework positions delayed childbearing as a multifaceted genetic risk factor that extend beyond aneuploidy to include mutations and other genomic alterations that can impact intergenerational genetic risk.

Aneuploidy

Vimentin loss inhibits DNA damage responses and promotes cancer cell survival.

Vimentin intermediate filaments are a hallmark of aggressive tumours and are widely linked to invasion and EMT, yet how vimentin-dependent mechanics shape genome maintenance and therapy response is unclear. Here we show that vimentin, particularly under compressive load, promotes DNA repair competence. In contrast, vimentin-negative cells show impaired DNA damage sensing and downstream signaling, ultimately leading to decreased apoptosis and promoting cell survival under genotoxic stress at the expense of genomic stability. Using controlled cell compression together with genetic and pharmacological perturbations, we find that loss of vimentin in glioblastoma cells limits the expression and activity of core repair pathways because of induced nuclear mechanical compression. Relieving nuclear compression restores DNA damage accumulation and repair kinetics. Functionally, suppression of DNA damage responses enhances survival after clinically relevant DNA-damaging treatments, including temozolomide, X-Ray radiation and cell invasion through tight spaces. These findings invert the prevailing view that vimentin's contribution to tumour progression stems from enhanced migration and identify a mechanochemical vimentin-nucleus axis that tunes DNA damage responses to favor therapy tolerance and genome evolution.

Journal Article

Differentiation-independent activation of HPV genome replication by the lncRNA DINO.

Human papillomaviruses (HPVs) rely on multiple host cell factors to replicate the viral genome, yet the contribution of host long non-coding RNAs (lncRNAs) to viral genome maintenance and amplification in the productive life cycle remains poorly understood. In this study, we show that the lncRNA damage-induced long non-coding RNA (DINO) is a driver of HPV DNA replication. DINO levels increase during keratinocyte differentiation, and ectopic expression of DINO promotes both HPV genome replication and the formation of replication foci, and this is independent of keratinocyte differentiation signals. Ectopic DINO expression increases select early viral transcript levels, including E1^E4, E1, and E2. Notably, DINO's subcellular localization is also context-dependent: during DNA damage, DINO is predominantly cytoplasmic, but during keratinocyte differentiation, nuclear retention is observed. This differential localization suggests that DINO has distinct functional roles in keratinocyte differentiation and HPV biology. Our findings highlight DINO as a lncRNA that promotes HPV genome replication and suggest that lncRNAs may play underappreciated roles in host-virus interactions. This work provides a foundation for further exploration of lncRNAs as potential therapeutic targets in HPV-associated diseases.IMPORTANCEHuman papillomaviruses (HPVs) are the causative agents of many anogenital tract and oral cancers, yet the host factors that trigger and support viral genome replication during the productive life cycle are incompletely understood. This study identifies the long non-coding RNA DINO as a host regulator that promotes HPV DNA replication, replication focus formation, and early viral gene expression independently of keratinocyte differentiation. We further show that DINO exhibits context-dependent subcellular localization, suggesting distinct functional roles in cellular stress responses and HPV biology. These findings reveal an underappreciated role for host lncRNAs in virus-host interactions and provide new insight into cellular pathways that support HPV genome replication.

Virus Replication

Context-dependent roles of DHX9 in Cancer: Molecular mechanisms, biomarker potential, and therapeutic perspectives.

DExH-box helicase 9 (DHX9) is a multifunctional nucleic acid helicase that participates in R-loop homeostasis, genome maintenance, RNA metabolism, and innate immune signaling. Accumulating evidence has linked aberrant DHX9 expression or activity to tumorigenesis, tumor progression, treatment response, and patient prognosis. However, its role in cancer is highly context-dependent, rather than uniformly oncogenic or tumor suppressive. Depending on its molecular partners, subcellular localization, post-translational modifications, tumor genotype, and immune microenvironment, DHX9 may either promote malignant phenotypes or contribute to tumor-restraining processes. In this review, we summarize the molecular characteristics and regulatory properties of DHX9, discuss its roles in genome stability, transcriptional and post-transcriptional control, circular RNA (circRNA) biogenesis, and tumor-immune crosstalk, and evaluate its emerging value as a potential biomarker and therapeutic target. We also highlight key challenges in this field, including mechanistic heterogeneity, insufficient translational validation, and the urgent need for context-informed patient stratification to maximize the clinical utility of DHX9-targeted strategies.

Humans

USP10-SIRT6-PARP1 axis drives keratinocyte senescence and skin photoaging under chronic UVA exposure.

Chronic exposure to ultraviolet A (UVA) radiation is the principal environmental driver of skin photoaging, yet the upstream molecular events that commit irradiated keratinocytes to senescence remain poorly understood. Here we show that SIRT6, an NAD+-dependent protein deacetylase with established roles in genome maintenance and organismal longevity, functions as a central gatekeeper of keratinocyte homeostasis under photic stress. Using a chronic UVA irradiation model in mice together with cultured human keratinocytes, we demonstrate that UVA inflicts extensive DNA damage and G2/M cell-cycle arrest, accompanied by selective depletion of SIRT6 among all sirtuin family members. Mechanistically, UVA suppresses the deubiquitinase USP10 at both transcriptional and post-transcriptional levels, thereby licensing ubiquitin-dependent proteasomal degradation of SIRT6. The resulting SIRT6 deficiency unleashes hyperactivation of the DNA-damage sensor PARP1, amplifying genomic injury signaling and driving keratinocytes into irreversible senescence with concomitant elaboration of a broad pro-inflammatory secretory programme encompassing chemokines and cytokines. Pharmacological reactivation of SIRT6 with the selective agonist UBCS039 reverses epidermal hyperplasia, attenuates DNA damage and senescence marker accumulation, and suppresses inflammatory mediator induction both in vivo and in vitro, establishing SIRT6 loss as a causal rather than correlative event. Furthermore, molecular docking and functional validation identify osthole, a plant-derived coumarin from the medicinal herb Cnidium monnieri, as a candidate SIRT6-engaging compound that counteracts UVA-induced senescence and inflammation in keratinocytes. Collectively, these findings define a USP10-SIRT6-PARP1 signaling axis whose disruption underlies cutaneous photoaging and suggest that SIRT6-directed strategies may offer therapeutic benefit against UV-driven tissue degeneration.

Animals

Characterization of the genomic and transcriptomic landscape of invasive non-mucinous lung adenocarcinoma based on IASLC grading.

BACKGROUND: The IASLC grading system has prognostic utility and potential therapeutic implications in invasive non-mucinous lung adenocarcinoma (LUAD), but the molecular basis underlying the grading spectrum remains unclear. METHODS: We performed whole-genome sequencing in 138 Chinese patients with invasive non-mucinous LUAD and RNA sequencing of 96 matched tumor-normal tissue pairs to systematically characterize the molecular features across grades, including coding driver events, mutational signatures, non-coding regulatory disruptions, and transcriptional programs. RESULTS: Compared with Grade 1-2 tumors, Grade 3 LUADs exhibited heightened invasive potential, manifested by more advanced stage, more frequent spread through air spaces, and independently worse survival. Grade 3 tumors had elevated tumor mutational burden and were enriched for alterations in genome maintenance and cell-cycle genes, including TP53, as well as genes implicated in DNA damage response, including ZFHX4. APOBEC-associated mutagenesis was selectively enriched in Grade 3 tumors independent of smoking status, consistent with an instability-associated phenotype. Recurrent non-coding regulatory disruptions affected lung lineage-defining genes, particularly surfactant-associated genes, and were correlated with reduced expression. Transcriptomic profiling revealed epithelial dedifferentiation, loss of pulmonary homeostatic programs, and activation of proliferative and stress-related pathways. Notably, MUC16 emerged as a convergent event linking genomic and transcriptional dysregulation, with coding mutations associated with higher expression and increased expression in Grade 3 tumors correlating with the proportion of high-grade histologic patterns. CONCLUSIONS: These findings provide a molecular framework for the IASLC grading spectrum and identify Grade 3 LUAD as a distinct instability-associated and dedifferentiated biological state.

IASLC grading