Copy Number Variation Analysis Research Articles

Unveiling the Power of Mitochondrial Fission and Fusion: A Five-Gene Signature for Personalized Prognosis in Gastric Cancer.

Mitochondrial fission and fusion play important roles in tumorigenesis, progression and therapy. Dysregulation of these processes may lead to tumor progression, and regulation of these processes may provide novel strategies for cancer therapy. The involvement of genes related to mitochondrial fission and fusion (MD) in gastric cancer (GC) remains poorly understood. The aim of this study was to establish an MD gene signature for GC patients and to investigate its association with prognosis, tumor microenvironment and treatment response in GC. We use the TCGA-GC database as the cohort, focusing specifically on genes associated with MD. We conducted identification and consistency clustering analysis of differentially expressed genes in MD, conducted MD gene mutation and copy number variation analysis, as well as correlation and functional enrichment analysis between MD gene cluster classification and immune infiltration. TCGA-GC and GSE15459 were used to construct training and validation cohorts for the model. We used various statistical methods, including Cox and Lasso regression, to develop the model. We validated the model using bulk transcriptome and single- cell transcriptome datasets (GSE13861, GSE26901, GSE66229, and GSE13450). We used GSEA enrichment, CIBERSORT algorithm, ESTIMATE, and TIDE to gain insight into the annotation of MD signature and the characterization of the tumor microenvironment. OncoPredict was used to analyze the relationship between the PRG signature and the drug sensitivity. We validated the expression of several key genes in MD signature on GC cell lines using quantitative real-time PCR (qRT-PCR). These MDs-related subtypes exhibited different prognosis and immune filtration patterns. A five-gene signature, comprising AGT, HCFC1, KIFC3, NOX4, and RIN1, was developed. There was a clear distinction in overall survival between low- and high-risk patients. The analyses showed further confirmation of the independent prognostic value of the gene signature. There was a notable correlation between the MD signature, immune infiltration and drug susceptibility. The expression levels of AGT, HCFC1, KIFC3, NOX4 and RIN1 mRNA were all increased in these GC cells. The MD signature has the capacity to significantly contribute to the prediction of personalized outcomes and the advancement of novel therapeutic strategies tailored for GC patients.

CNVs in Patients with Neurodevelopmental Disorders: Meta-Analysis

This review is devoted to a comprehensive analysis of DNA copy number variations (CNVs) identified in patients with neurodevelopmental disorders (NDDs) from the literature. The selection of publications was conducted using specifically developed criteria. CNVs were characterized based on their clinical significance, type of copy number alteration (microdeletion/microduplication), size, origin, and gene content. The study sample comprised 3,375 patients with NDDs, among whom pathogenic and likely pathogenic CNVs, as well as variants of uncertain clinical significance, were identified in 395 individuals (12%). Chromosomal variations from each category were identified in 89 (3%), 56 (2%), and 241 (7%) patients, respectively. Nine individuals exhibited combinations of CNVs with varying clinical significance. The number of microduplications slightly exceeded the number of deletions (250 and 204, respectively). The size of most CNVs ranged from 193 bp to 400 kb and from 1 to 3 Mb (237 and 96, respectively). Seventy-two variants originated de novo, while 165 were inherited. Eighty-six CNVs were associated with 33 known microdeletion/microduplication syndromes. The most prevalent syndromes included 1q21.1 microduplication (7/395, 1.8%) (OMIM: 612475), 2p16.3 microdeletion (9/395, 2.3%) (OMIM: 614332), 15q13.3 microdeletion (7/395, 1.8%) (OMIM: 612001), 16p11.2 microdeletion (9/395, 2.3%) (OMIM: 611913), and 22q11.2 microduplications (7/395, 1.8%) (OMIM: 608363). Enrichment analysis revealed that pathogenic CNVs, as well as variants of uncertain clinical significance, are enriched in genes associated with abnormal behavioral/neurological phenotypes. Likely pathogenic CNVs included genes linked to disorders of the nervous system and homeostasis/metabolism.

7826 The Identification of an Activating ESR1 Mutation in an Aggressive Prolactinoma Enabled the Use of Personalized Treatment

Abstract Disclosure: T. Paes: None. J.B. Mebarak: None. J. C. Magnotto: None. G. A. Stamatiades: None. Y. Kuang: None. C. Paweletz: None. E.R. Laws: None. R.S. Carroll: None. R. Jeselsohn: None. D. R. Mohan: None. A. Marcondes Lerario: None. W. L. Bi: None. D. A. Reardon: None. D. M. Meredith: None. U.B. Kaiser: None. A. Abreu: None. Introduction: Prolactinomas are benign tumors typically treated with dopamine agonists; few progress on medical therapy, through unclear molecular mechanisms. Although the SF3B1 mutation has been identified in one study as a driver of aggressive prolactinomas, in most cases no genetic mutations have been reported. We aimed to identify genetic alterations associated with prolactinomas using a gene panel. Method and Results: Oncopanel, a massively parallel sequencing panel, was performed to identify genomic variants and copy number variation (CNV) in a cohort of 21 patients with prolactinomas. No SF3B1 pathogenic variants were identified in this cohort. A MEN1 mutation was detected in a macroadenoma resistant to dopamine agonist. In a case of an extremely aggressive prolactinoma diagnosed in a 49-year-old woman, a somatic ESR1 [encoding estrogen receptor alpha (ERα)] mutation (ESR1Y537S) was identified in tissue from the patient’s fourth surgery. Using droplet digital PCR (ddPCR), ESR1Y537S was also detected in circulating cell-free DNA. We aimed to investigate whether ESR1Y537S may have driven initial tumor formation, or whether it was acquired as the tumor progressed. To this end, Sanger sequencing and ddPCR analyses of DNA from the first two resected tumors were performed and failed to identify ESR1Y537S. In the CNV analysis, the ESR1-mutated prolactinoma had the highest number of CNVs, compared to the rest of the cohort. Despite efforts to control tumor growth with multiple therapeutic modalities, the mutated prolactinoma had progressively enlarged post-menopausally, with invasion of surrounding structures. ESR1Y537S is a hotspot mutation in metastatic breast cancer. In breast cancer cells, ESR1Y537S activates the ERα independent of ligand binding, resulting in high cell proliferation and conferring resistance to classic hormonal treatment in ER-positive breast cancer. Elacestrant, a second-line ER degrader, increases overall free-survival in patients with resistant breast cancer and ESR1Y537S. Given the lack of response to multimodality therapy, off-label elacestrant was initiated after the third cycle of radiotherapy was completed in the patient with the aggressive prolactinoma. The combination of radiotherapy with this personalized treatment targeting ESR1 activity (elacestrant) was able to control tumor growth and significantly reduce prolactin levels. Conclusion:ESR1 regulates lactotroph differentiation and proliferation, possibly contributing to prolactinoma tumorigenesis. Our data support a role for ESR1Y537S in this prolactinoma’s unusually aggressive behavior in the postmenopausal setting. Molecular profiling revealing the mutation (ESR1Y537S) allowed the patient to receive a targeted therapy which, together with radiotherapy, resulted in a decrease in prolactin levels and a remarkable improvement in disease control. Presentation: 6/2/2024

UBTF haploinsufficiency associated with UBTF-related global developmental delay and distinctive facial features without neuroregression

BackgroundThe Upstream Binding Transcription Factor (UBTF) gene encodes two nucleolar proteins, UBTF1 and UBTF2. UBTF1 regulates rRNA transcription by RNA polymerase I, while UBTF2 regulates mRNA transcription by RNA polymerase...

Adaptive copy number variations of ancient prokaryotic genes in marine fish colonization

During extensive evolution, higher eukaryotes have acquired numerous prokaryotic genes, some of which have experienced adaptive copy number variations (CNVs) in response to changing environments. The specific contribution of ancient prokaryotic genes to the evolutionary dynamics of marine fish remains unclear. In this study, we investigated ancient prokaryotic genes in 33 freshwater and 14 non-freshwater fish species. Non-freshwater fish exhibited a higher proportion of these genes (25.84 %) compared to freshwater fish (17.66 %), though functional categories showed similarity, suggesting genetic conservation. Comprehensive CNV analysis identified 24 genes with significantly higher copy numbers in non-freshwater fish, enriched in glycerolipid metabolism, immune regulation, and catechol O-methyltransferase activity. Eight of these genes displayed increased copy numbers in marine populations compared to Asian freshwater populations. These findings indicate that CNVs in genes related to glycerolipid metabolism, immune regulation, and methyltransferase activity may play crucial roles in marine adaptation at global and regional evolutionary scales.

Contribution of Genomic Imbalance in Prenatal Congenital Anomalies of the Kidney and Urinary Tract: A Multi-Center Cohort Study.

To investigate the diagnostic utility of copy-number variant (CNV) detection by chromosomal microarray analysis (CMA) and genotype-phenotype associations in prenatal congenital anomalies of the kidney and urinary tract (CAKUT). This is a retrospective multi-center study of CNV analysis in 457 fetuses with ultrasound-detected CAKUT and normal karyotypes. Cohorts from published studies were included for further pooled analyses (N=2746). A literature review of single-nucleotide variant (SNV) and small insertions and deletions (Indel) analysis by whole-exome sequencing was performed to investigate monogenic causes. In our multi-center cohort, 5.3% (24/457) of fetuses had pathogenic CNVs (pCNV); 3.9% (14/359) and 10.2% (10/98) in isolated and non-isolated CAKUT, respectively. Fetuses with isolated hyperechogenic kidneys (HEK) had the highest incidence of having pCNVs. In the literature review, 6.6% (180/2746) of fetuses carried pCNVs; 6.1% and 7.5% in isolated and non-isolated CAKUT, respectively. SNV/Indel analysis provided at least 16.5% (63/381) additional diagnostic yield beyond CNV analysis; 12.8% and 23.8% in isolated and non-isolated CAKUT, respectively. pCNVs comprise a significant proportion of genetic diagnostic findings in prenatal CAKUT, most commonly detected in fetuses with isolated HEK, MCDK, renal agenesis, and non-isolated CAKUT. Monogenic causes should be considered when karyotyping and CMA are nondiagnostic.

Serial single-cell RNA sequencing unveils drug resistance and metastatic traits in stage IV breast cancer

Metastasis is a complex process that remains poorly understood at the molecular levels. We profiled single-cell transcriptomic, genomic, and epigenomic changes associated with cancer cell progression, chemotherapy resistance, and metastasis from a Stage IV breast cancer patient. Pretreatment- and posttreatment-specimens from the primary tumor and distant metastases were collected for single-cell RNA sequencing and subsequent cell clustering, copy number variation (CNV) estimation, transcriptomic factor estimation, and pseudotime analyses. CNV analysis revealed that a small population of pretreatment cancer cells resisted chemotherapy and expanded. New clones including Metastatic Precursor Cells (MPCs), emerged in the posttreatment primary tumors in CNV similar to metastatic cells. MPCs exhibited expression profiles indicative of epithelial–mesenchymal transition. Comparison of MPCs with metastatic cancer cells also revealed dynamic changes in transcription factors and calcitonin pathway gene expression. These findings demonstrate the utility of single-patient clinical sample analysis for understanding tumor drug resistance, regrowth, and metastasis.

EP.06F.03 Analysis of Copy Number Variations of MET, EGFR and ERBB2 Genes in a Lung Cancer Patient Series: Comparison of FISH with NGS

EP.06F.03 Analysis of Copy Number Variations of MET, EGFR and ERBB2 Genes in a Lung Cancer Patient Series: Comparison of FISH with NGS

Dissecting the Single-Cell Diversity and Heterogeneity Underlying Cervical Precancerous Lesions and Cancer Tissues.

The underlying cellular diversity and heterogeneity from cervix precancerous lesions to cervical squamous cell carcinoma (CSCC) is investigated. Four single-cell datasets including normal tissues, normal adjacent tissues, precancerous lesions, and cervical tumors were integrated to perform disease stage analysis. Single-cell compositional data analysis (scCODA) was utilized to reveal the compositional changes of each cell type. Differentially expressed genes (DEGs) among cell types were annotated using BioCarta. An assay for transposase-accessible chromatin sequencing (ATAC-seq) analysis was performed to correlate epigenetic alterations with gene expression profiles. Lastly, a logistic regression model was used to assess the similarity between the original and new cohort data (HRA001742). After global annotation, seven distinct cell types were categorized. Eight consensus-upregulated DEGs were identified in B cells among different disease statuses, which could be utilized to predict the overall survival of CSCC patients. Inferred copy number variation (CNV) analysis of epithelial cells guided disease progression classification. Trajectory and ATAC-seq integration analysis identified 95 key transcription factors (TF) and one immunohistochemistry (IHC) testified key-node TF (YY1) involved in epithelial cells from CSCC initiation to progression. The consistency of epithelial cell subpopulation markers was revealed with single-cell sequencing, bulk sequencing, and RT-qPCR detection. KRT8 and KRT15, markers of Epi6, showed progressively higher expression with disease progression as revealed by IHC detection. The logistic regression model testified the robustness of the resemblance of clusters among the various datasets utilized in this study. Valuable insights into CSCC cellular diversity and heterogeneity provide a foundation for future targeted therapy.

Importance of Copy Number Variant Analysis in Patients with Monogenic Kidney Diseases: Insights from 8 Years of Experience in an Expert Centre's Genome Diagnostic Laboratory

Importance of Copy Number Variant Analysis in Patients with Monogenic Kidney Diseases: Insights from 8 Years of Experience in an Expert Centre's Genome Diagnostic Laboratory

Diagnostic yield of exome sequencing-based copy number variation analysis in Mendelian disorders: a clinical application

Next-generation sequencing (NGS) coupled with bioinformatic tools has revolutionized the detection of copy number variations (CNVs), which are implicated in the emergence of Mendelian disorders. In this study, we evaluated the diagnostic yield of exome sequencing-based CNV analysis in 449 patients with suspected Mendelian disorders. We aimed to assess the diagnostic yield of this recently utilized method and expand the clinical spectrum of intragenic CNVs. The cohort underwent whole exome sequencing (WES) and clinical exome sequencing (CES). Using GATK-gCNV, we identified 12 pathogenic CNVs that correlated with their clinical findings and resulting in a diagnostic yield of 2.67%. Importantly, the study emphasizes the role of CNVs in the etiology of Mendelian disorders and highlights the value of exome sequencing-based CNV analysis in routine diagnostic processes.

Genome-Wide Association Studies of Hair Whorl in Pigs.

In pigs, a hair whorl refers to hairs that form a ring of growth around the direction of the hair follicle at the dorsal hip. In China, a hair whorl is considered a negative trait that affects marketing, and no studies have been conducted to demonstrate whether hair whorl affects pig performance and provide an explanation for its genetic basis. Performance-measured traits and slaughter-measured traits of hair whorl and non-hair whorl pigs were differentially analyzed, followed by genome-wide association analysis (GWAS) and copy number variation (CNV) methods to investigate the genetic basis of hair whorl in pigs. Differential analysis of 2625 pigs (171 hair whorl and 2454 non-hair whorl) for performance measures showed that hair whorl and non-hair whorl pigs differed significantly (p < 0.05) in traits such as live births, total litter size, and healthy litter size (p < 0.05), while differential analysis of carcass and meat quality traits showed a significant difference only in the 45 min pH (p = 0.0265). GWAS identified 4 SNP loci significantly associated with the hair whorl trait, 2 of which reached genome-significant levels, and 23 candidate genes were obtained by annotation with the Ensembl database. KEGG and GO enrichment analyses showed that these genes were mainly enriched in the ErbB signaling, endothelial apoptosis regulation, and cell proliferation pathways. In addition, CNV analysis identified 652 differential genes between hair whorl and non-hair whorl pigs, which were mainly involved in the signal transduction, transcription factor activity, and nuclear and cytoplasmic-related pathways. The candidate genes and copy number variation differences identified in this study provide a new theoretical basis for pig breeding efforts.

Benchmarking of Approaches for Gene Copy-Number Variation Analysis and Its Utility for Genetic Aberration Detection in High-Grade Serous Ovarian Carcinomas.

Objective: The goal of this study was to compare the results of CNV detection by three different methods using 13 paired carcinoma samples, as well as to perform a statistical analysis of the agreement. Methods: CNV was studied using NanoString nCounter v2 Cancer CN Assay (Nanostring), Illumina Infinium CoreExome microarrays (CoreExome microarrays) and digital droplet PCR (ddPCR). Results: There was a good level of agreement (PABAK score > 0.6) between the CoreExome microarrays and the ddPCR results for finding CNVs. There was a moderate level of agreement (PABAK values ≈ 0.3-0.6) between the NanoString Assay results and microarrays or ddPCR. For 83 out of 87 target genes studied (95%), the agreement between the CoreExome microarrays and NanoString nCounter was characterized by PABAK values < 0.75, except for MAGI3, PDGFRA, NKX2-1 and KDR genes (>0.75). The MET, HMGA2, KDR, C8orf4, PAX9, CDK6, and CCND2 genes had the highest agreement among all three approaches. Conclusions: Therefore, to get a better idea of how to genotype an unknown CNV spectrum in tumor or normal tissue samples that are very different molecularly, it makes sense to use at least two CNV detection methods. One of them, like ddPCR, should be able to quantitatively confirm the results of the other.

Molecular and cytogenetic characterization of Osteospermum fruticosum lines harboring wild type pRi rol genes.

Transgenic lines engineered through wild type Rhizobium rhizogenes display an altered phenotype known as the Ri phenotype. This phenotype includes a more compact plant habit, which has proved useful to obtain more compact varieties that require less chemical growth regulation. Here, we develop a method for the molecular and cytogenetic characterization of Cape daisy (Osteospermum fruticosum Norl.) Ri lines in order to predict segregation of pRi T-DNA genes. Analysis of copy number variation (CNV) by means of digital PCR indicated large variation in the copy number of the inserted root oncogenic loci (rol) genes, ranging from 1 to more than 15 copies. In addition, up to 9 copies of the auxin biosynthesis genes (aux) were present in a single Ri line. Visualization of pRiA4 and pRi1724 rol and aux insertion in 4 Ri lines was performed through Fluorescence In Situ Hybridization. The number of rol integrated loci varied from 1 to 3 loci. In contrast, the different TR-gene copies were confined to a single locus which consistently co-localized with a TL locus, this was demonstrated for the first time. Based on CNV and FISH a single Ri line, harboring 7 pRi1724 rol gene copies dispersed over 3 integration loci, was selected for breeding. Copy number segregation in R1 progeny of 2, 3, 4 and 5 pRi1724 copies was confirmed, indicating that the evaluation of the breeding value of first generation Ri lines is possible through CNV and FISH.

Landscape of epithelial cell subpopulations in the human esophageal squamous cell carcinoma microenvironment

AimsWe sought to reveal the landscape of epithelial cell subpopulations in the human esophageal squamous cell carcinoma microenvironment and investigate their parts on esophageal squamous carcinoma (ESCC) development. BackgroundEpithelial cells play an important role in the occurrence and development of ESCC through multiple mechanisms. While the landscape of epithelial cell subpopulations in ESCC, remains unclear. ObjectiveExploring the role of epithelial cell subpopulations in ESCC progression. MethodsSeurat R package was used for single-cell RNA sequencing (scRNA-seq) data filtering, dimensionality reduction, clustering and differentially expressed genes analysis. Cellmarker database was adopted for cell cluster annotation. Functional enrichment analysis was carried out by Gene Ontology (GO) analysis. InferCNV package was conducted for copy number variation (CNV) of epithelial cell subpopulations in all chromosomal regions. Pseudotime trajectory analysis was implemented for exploring differentiation trajectory of epithelial cells subgroups during the cancer progression. CellChat analysis was used for probing the interactions between epithelial cells and NK/T cells. cellular experiments were performed using Quantitative Real-Time Polymerase Chain Reaction (RT-qPCR), Wound-Healing Assay and transwell. Results11 major cell subpopulations were identified in ESCC and adjunct tissues. Further reclassification of epithelial cells uncovered 4 subpopulations. Enrichment analysis revealed that highly expressed genes in 4 epithelial cell subpopulations were related to cell proliferation, immune response and angiogenesis. CNV analysis found that UBD + epithelial cells and GAS2L3+ epithelial cells had a higher proportion of CNV. Cell differentiation trajectories disclosed that KRT6C+ and GSTA1+ epithelial cells were in an intermediate state of differentiation, while UBD+ and GAS2L3+ epithelial cells are in an end state of differentiation during ESCC progression. Finally, we found that four epithelial cell subpopulations all inhibited NK/T cells through NECTIN2-TIGIT and CLEC2B-KLRB1. Low ATF3 and DDIT3 mRNA expression inhibited ESCC cell migration and invasion. ConclusionHere, we obtained a through epithelial cell atlas of ESCC at single-cell resolution, explored the role of epithelial cell in ESCC progression, and unveiled immunosuppressive signals to NK/T cells in promoting ESCC. Our findings expand the comprehension of epithelial cells and offer a theoretical guidance for future anti-epithelial cell treatment of ESCC.

AMAR-seq: Automated Multimodal Sequencing of DNA Methylation, Chromatin Accessibility, and RNA Expression with Single-Cell Resolution.

Parallel single-cell multimodal sequencing is the most intuitive and precise tool for cellular status research. In this study, we propose AMAR-seq to automate methylation, chromatin accessibility, and RNA expression coanalysis with single-cell precision. We validated the accuracy and robustness of AMAR-seq in comparison with standard single-omics methods. The high gene detection rate and genome coverage of AMAR-seq enabled us to establish a genome-wide gene expression regulatory atlas and triple-omics landscape with single base resolution and implement single-cell copy number variation analysis. Applying AMAR-seq to investigate the process of mouse embryonic stem cell differentiation, we revealed the dynamic coupling of the epigenome and transcriptome, which may contribute to unraveling the molecular mechanisms of early embryonic development. Collectively, we propose AMAR-seq for the in-depth and accurate establishment of single-cell multiomics regulatory patterns in a cost-effective, efficient, and automated manner, paving the way for insightful dissection of complex life processes.

Genetic analysis of pregnancy loss and fetal structural anomalies by whole exome sequencing

BackgroundWhole exome sequencing (WES) has been recommended to investigate the genetic cause of fetal structural anomalies. In this retrospective study, we aimed to evaluate the diagnostic yield of WES in our cohort of families with pregnancy loss or termination of pregnancy due to structural anomalies.MethodsAs aneuploidy, triploidy and copy number variations (CNVs) could be detected by exome-based CNV analysis, only WES is performed in this study. And the results of 375 cases assessed by WES were analyzed.ResultsThe overall detection rate was 32.3% (121/375), including aneuploidy and triploidy (7.5%, 28/375), CNVs (5.1%, 19/375) and single-nucleotide variants (SNVs) /insertions or deletions (Indels) (19.7%, 74/375). Among these, the diagnostic yield for likely pathogenic (LP) or pathogenic (P) CNVs is 4.8% (18/375), and the diagnostic yield for LP or P SNVs/Indels is 15.2% (57/375). And an additional 4.8% (18/375) of cases had CNVs or SNVs/Indels classified as variants of uncertain significance (VUS) with potential clinical significance.ConclusionsOur findings expand the known mutation spectrum of genetic variants related to fetal abnormalities, increase our understanding of prenatal phenotypes, and enable more accurate counseling of recurrence risk for future pregnancies.

De novo and inherited micro-CNV at 16p13.11 in 21 Chinese patients with defective cardiac left-right patterning.

Copy number changes at Chromosomal 16p13.11 have been implicated in a variety of human diseases including congenital cardiac abnormalities. The clinical correlation of copy number variants (CNVs) in this region with developmental abnormalities remains controversial as most of the patients inherit the duplication from an unaffected parent. We performed CNV analysis on 164 patients with defective left-right (LR) patterning based on whole genome-exome sequencing (WG-ES) followed by multiplex ligation-dependent probe amplification (MLPA) validation. Most cases were accompanied with complex congenital heart disease (CHD). CNVs at 16p13.11 were identified in a total of 21 cases, accounting for 12.80% (21/164) evaluated cases. We observed a marked overrepresentation of chromosome 16p13.11 duplications in cases when compared with healthy controls according to literature reports (15/164, 9.14% versus 0.09% in controls). Notably, in two independent family trios, de novo 16p13.11 micro-duplications were identified in two patients with laterality defects and CHD. Moreover, 16p13.11 micro-duplication was segregated with the disease in a family trio containing 2 affected individuals. Notably, five coding genes, NOMO1, PKD1P3, NPIPA1, PDXDC1, and NTAN1, were potentially affected by micro-CNV at 16p13.11 in these patients. Our study provides new family-trio based evidences to support 16p13.11 micro-duplications predispose individuals to defective cardiac left-right patterning and laterality disorder.

Deciphering genetic and nongenetic factors underlying tumour dormancy: insights from multiomics analysis of two syngeneic MRD models of melanoma and leukemia

BackgroundTumour dormancy, a resistance mechanism employed by cancer cells, is a significant challenge in cancer treatment, contributing to minimal residual disease (MRD) and potential relapse. Despite its clinical importance, the mechanisms underlying tumour dormancy and MRD remain unclear. In this study, we employed two syngeneic murine models of myeloid leukemia and melanoma to investigate the genetic, epigenetic, transcriptomic and protein signatures associated with tumour dormancy. We used a multiomics approach to elucidate the molecular mechanisms driving MRD and identify potential therapeutic targets.ResultsWe conducted an in-depth omics analysis encompassing whole-exome sequencing (WES), copy number variation (CNV) analysis, chromatin immunoprecipitation followed by sequencing (ChIP-seq), transcriptome and proteome investigations. WES analysis revealed a modest overlap of gene mutations between melanoma and leukemia dormancy models, with a significant number of mutated genes found exclusively in dormant cells. These exclusive genetic signatures suggest selective pressure during MRD, potentially conferring resistance to the microenvironment or therapies. CNV, histone marks and transcriptomic gene expression signatures combined with Gene Ontology (GO) enrichment analysis highlighted the potential functional roles of the mutated genes, providing insights into the pathways associated with MRD. In addition, we compared “murine MRD genes” profiles to the corresponding human disease through public datasets and highlighted common features according to disease progression. Proteomic analysis combined with multi-omics genetic investigations, revealed a dysregulated proteins signature in dormant cells with minimal genetic mechanism involvement. Pathway enrichment analysis revealed the metabolic, differentiation and cytoskeletal remodeling processes involved in MRD. Finally, we identified 11 common proteins differentially expressed in dormant cells from both pathologies.ConclusionsOur study underscores the complexity of tumour dormancy, implicating both genetic and nongenetic factors. By comparing genomic, transcriptomic, proteomic, and epigenomic datasets, our study provides a comprehensive understanding of the molecular landscape of minimal residual disease. These results provide a robust foundation for forthcoming investigations and offer potential avenues for the advancement of targeted MRD therapies in leukemia and melanoma patients, emphasizing the importance of considering both genetic and nongenetic factors in treatment strategies.Graphical

Differential Cellular Response to Mercury in Non-Farmed Fish Species Based on Mitochondrial DNA Copy Number Variation Analysis.

Mercury (Hg) pro-oxidant role on biological systems and its biogeochemical cycle represent a serious threat due to its persistence in marine environment. As the mitochondrial genome is exposed to reactive oxygen species (ROS), the aim of the present study is the validation of the variation in the number of mitochondrial DNA copies (mtDNAcn) as biomarker of oxidative stress in aquatic environment. During summer 2021, three selected fish species (Mullus barbatus, Diplodus annularis and Pagellus erythrinus) were collected in Augusta Bay, one of the most Mediterranean contaminated areas remarkable by past Hg inputs, and in a control area, both in the south-east of Sicily. The relative mtDNAcn was evaluated by qPCR on specimens of each species from both sites, characterized respectively by higher and lower Hg bioaccumulation. M. barbatus and P. erythrinus collected in Augusta showed a dramatic mtDNAcn reduction compared to their control groups while D. annularis showed an incredible mtDNAcn rising suggesting a higher resilience of this species. These results align with the mitochondrial dynamics of fission and fusion triggered by environmental toxicants. In conclusion, we suggest the implementation of the mtDNAcn variation as a valid tool for the early warning stress-related impacts in aquatic system.