ABSTRACT Cutaneous melanoma, a highly aggressive and therapy-resistant skin cancer, is characterized by its remarkable cellular plasticity, enabling tumour cells to switch between different phenotypic states. This plasticity contributes to tumour heterogeneity and is regulated by key transcription factors. Long non-coding RNAs (lncRNAs) are emerging as crucial regulators in melanoma progression, yet much remains to be explored regarding their role in phenotype switching. In this study, we analysed long non-coding RNAs (lncRNAs) across different murine melanoma cell lines, identifying a set of lncRNAs potentially involved in regulating melanoma phenotypic state through cis-regulation of neighbouring protein-coding genes. We demonstrated that the lncRNA Dlx4os regulates genes associated with melanoma plasticity, favouring a mesenchymal-like, undifferentiated state. Dlx4os knockdown redirected melanoma cells to a more differentiated and less malignant phenotype, confirmed by differential expression of phenotypic state markers (Sox10, Mitf, Tgfβ, Sox6, Mlana), reduced their invasive and migratory potential, and delayed tumour progression in vivo. Furthermore, we identified a human orthologue of Dlx4os. Our findings highlight the potential of Dlx4os as both a biomarker and therapeutic target, capable of modulating melanoma’s phenotypic plasticity to influence treatment response and metastasis.

ABSTRACT DNA methylation is among the most promising biomarkers for age prediction, enabling the development of epigenetic clocks that correlate methylation profiles with chronological age. In this study, we investigated the relationship between ageing and disease susceptibility, focusing on both nuclear and mitochondrial DNA methylation in dairy cows. Genome-wide DNA methylation profiling was performed using enzymatic methyl-seq, covering 53 million CpG sites. The dataset included 96 cows with different phenotypes, sampled cross-sectionally and ranging from 2 to 9 years of age. We applied elastic net regression to identify the most predictive CpG sites for age estimation, achieving a mean absolute error of 111 days with a strong correlation to chronological age r = 0.97. Beyond chronological age prediction, we assessed the impact of disease status on epigenetic ageing. Our results revealed accelerated epigenetic ageing in cows susceptible to diseases, suggesting a link between health-related stress and disrupted DNA methylation dynamics. We further identified age-associated promoter methylation changes, particularly in MAB21L1, which may play a role in molecular ageing mechanisms. Additionally, we observed a decline in mitochondrial DNA methylation with age, notably in genes encoding Cytochrome c oxidase (COX), indicating a possible connection between mitochondrial dysfunction and epigenetic regulation. An inverse correlation between D-loop methylation and mtDNA copy number was also observed. This study demonstrates the potential of epigenetic models for biological age prediction in livestock, while recognizing that their accuracy may vary among species with different lifespans.

ABSTRACT Environmental factors can influence gene expression and developmental outcomes through epigenetic modifications. Although maternal diet influences offspring DNA methylation and phenotypes, its effects on the oocyte and the resulting embryonic epigenome remain poorly understood. Here, we investigated the effect of maternal methionine supplementation on DNA methylation patterns in oocytes and embryos in Polypay sheep. Whole-genome bisulfite sequencing (WGBS) was performed on oocytes collected from 16 twin ewe pairs (8 methionine-treated and 8 controls). These ewes were later bred to control rams, and embryos were flushed for WGBS as well. In oocytes, 2,056 differentially methylated cytosines (DMCs) were identified. Additionally, 17 mitochondrial DMCs were identified, with 12 hypermethylated and 5 hypomethylated. In embryos, 113 DMCs were identified. Mitochondrial DNA analysis revealed 22 hypermethylated DMCs. To assess the inheritance of methyl marks, we compared DMCs between oocytes and embryos. While no direct overlaps were found in nuclear DNA, 3 CpGs exhibited opposite methylation trends – hypomethylated in oocytes but hypermethylated in embryos. In contrast, 5 mitochondrial DMCs overlapped between oocytes and embryos. To functionally assess the role of differentially methylated genes, we performed siRNA-mediated knockdown of 2 embryo DMC-associated genes: SCRIB and CERS3. Knockdown of SCRIB led to a 16.4% average decrease in blastocyst formation rate (p = 0.001), while CERS3 knockdown resulted in a 9.5% decrease (p = 0.005). These results demonstrate that maternal methionine supplementation alters nuclear and mitochondrial DNA methylation in oocytes and embryos, and that affected genes may play critical roles in early embryonic development, contributing to fetal programming.

ABSTRACT The Systemic Immune-Inflammation Index (SII), a marker of systemic inflammation, has been linked to various age-related diseases, but its association with Epigenetic Age Acceleration (EAA) remains underexplored. This study aimed to investigate the SII and EAA relationship. We analysed data from 1,915 participants from the National Health and Nutrition Examination Survey (NHANES). SII was calculated as platelet count × (neutrophil count/lymphocyte count). EAA was defined as HorvathAccel, HannumAccel, Skin&BloodAccel, PhenoAgeAccel, GrimAge2Accel, and DunedinPoAm. These metrics were derived utilizing the residual method. Multivariate linear regression, smooth curve fitting, threshold effect analyses, and subgroup analyses were employed to assess the relationship between the SII and EAA. Higher SII levels were significantly associated with HannumAccel, PhenoAgeAccel, GrimAge2Accel, and DunedinPoAm. Threshold effect analyses revealed non-linear relationships, with inflection points at SII values of 24.200, 12.553, 7.766, and 10.133, respectively. Subgroup analyses identified sex, age, poverty-to-income ratio, and marital status as significant effect modifiers. The elevated SII was associated with accelerated epigenetic ageing.

ABSTRACT Fumonisin B1 (FB1) is a common maize contaminant known to induce toxicity and carcinogenesis in humans and animals; however, its epigenetic mechanisms remain poorly understood. DNA methylation is an epigenetic modification that controls gene expression through DNA methyltransferase and demethylase activities. In this study, the effect of FB1 on DNA methylation in brain glioblastoma U87MG cells was evaluated. FB1 cytotoxicity was determined by the MTT assay and an IC50 value of 880 µM FB1 was obtained. The ELISA-based global DNA methylation assay displayed an increase in 5-methylcytosine levels. qPCR and western blot revealed a significant increase in DNA methyltransferase expressions (DNMT1, DNMT3A, and DNMT3B) and a significant decrease in demethylase expression (MBD2). This data indicates that FB1 induces global DNA hypermethylation, through increased DNA methyltransferase expressions and DNA demethylase suppression in U87MG cells, thus suggesting an alternative mechanism of toxicity.

ABSTRACT Gastric cancer (GC) is one of the most common malignancies with limited treatment options and poor prognosis. Therefore, it is necessary to identify new markers for the development of novel therapeutic strategies. Long non-coding RNAs (lncRNAs) have emerged as pivotal players in cancer. However, RNA-based cancer therapy has been challenged by non-specificity and adverse immune effects. Thus, a comprehensive understanding of the functional roles of lncRNAs and their regulatory networks in downstream pathways may provide more specific targets. In this study, we identified a novel lncRNA, Lnc21q22.11, encoded by the region of chromosome 21q22.11. The full-length transcript was 1202 nt, and its expression was reduced in GC. The expression of Lnc21q22.11 was regulated by histone methylation. Lnc21q22.11 inhibited GC cell proliferation, colony formation, invasion, and migration. Lnc21q22.11 suppressed N87 cell xenograft growth in mice. Mechanistically, Lnc21q22.11 inhibited the mitogen-activated protein kinase kinase/extracellular signal-regulated kinase (MEK/ERK) signaling pathway by interacting with MYH9 in GC cells. Loss of or reduced Lnc21q22.11 expression sensitized GC cells to MEK inhibitor. In conclusion, Lnc21q22.11 is a novel lncRNA in gastric cancer. It suppresses gastric cancer growth by inhibiting the MEK/ERK signaling pathway both in vitro and in vivo.

ABSTRACT Colorectal cancer (CRC) remains an alarming global health concern despite advancements in treatment modalities over recent decades. Among the various factors contributing to CRC, this review emphasizes the critical role of epigenetic mechanisms in its pathogenesis and progression. This review also describes the potential role of natural compounds in altering the epigenetic landscape, focused mainly on DNA methylation, histone modification, and non-coding RNAs. Publications from the previous five years were searched and retrieved using well-known search engines and databases like PubMed, Google Scholar, and ScienceDirect. Keywords like CRC/colorectal cancer, CAC/Colitis associated CRC, inflammasomes, epigenetic modulation, genistein, curcumin, quercetin, resveratrol, anthocyanins, sulforaphane, and epigallocatechin-3-gallate were used in various combinations during the search. These natural compounds predominantly affect pathways such as Wnt/β-catenin, NF-κB, and PI3K/AKT to suppress CRC cell proliferation and oxidative stress and enhance anti-inflammation and apoptosis. However, their clinical use is restricted due to their low bioavailability. However, multiple methods exist to overcome challenges like this, including but not limited to structural modifications, nanoparticle encapsulations, bio-enhancers, and novel advanced delivery systems. These methods improve their potential as supportive therapies that target CRC progression epigenetically with fewer side effects. Current research focuses on enhancing epigenetic targeting to control CRC progression while minimizing side effects, emphasizing improved specificity, bioavailability, and efficacy as standalone or synergistic therapies.

ABSTRACT Skin cutaneous melanoma (SKCM) is an aggressive tumor with a poor prognosis. We developed SKCM-P8, a novel qualitative prognostic biomarker based on the relative methylation orderings of eight pairs of loci. Analysis of a training cohort and two independent validation datasets revealed a significant difference in overall survival between high- and low-risk groups stratified by SKCM-P8 (p < 0.05, log-rank test), with average area under the curve values of 0.83, 0.80, and 0.61, respectively. The differential methylation loci between high- and low-risk patients were enriched in immune-related biological processes and signaling pathways. Furthermore, low-risk patients exhibited higher CD8+ T cells and B levels, while high-risk patients had higher monocytes. The methylation levels of SKCM-P8 were also correlated with immune cell levels, indicating that they can reflect prognosis-related immune information. The low-risk group had a significantly higher mutation burden (p < 0.05, Wilcoxon test), suggesting potential benefits from immune checkpoint inhibitors. Patients stratified by SKCM-P8 displayed differential responses to therapy and immunotherapy (p < 0.05, Wilcoxon test), with low-risk patients showing better sensitivity and response. Furthermore, SKCM-P8 demonstrated super-predictive accuracy compared to six published models. Overall, SKCM-P8 offers a promising tool for predicting prognosis and guiding therapeutic decisions in SKCM.

ABSTRACT The incidence rate of breast cancer (BC) ranks first among female malignant tumors. Late-stage BC patients are at risk of death from distant metastasis. Circular RNAs (circRNAs) play an important function in cancer development. This study looked at the role of circMYH9 in BC. The nude mouse tumor-bearing experiment was used to verify the role of circMYH9 in regulating BC tumor growth in mice. Gene expression and protein amount were tested by qRT-PCR, western blot, and IHC. The pathological changes in tumor tissues were analyzed by HE staining. Cell viability, proliferation, migration, and invasion were assessed using CCK8, colony formation assay, wound healing assay, and Transwell assay, respectively. The interactions between circMYH9, SPAG6, and EIF4A3 were analyzed by RIP assay. CircMYH9 was significantly upregulated in BC, and its upregulated was related to poor prognosis. CircMYH9 silencing markedly impaired BC cell proliferation, migration, and invasion. Mechanistically, circMYH9 promoted the mRNA stability and expression of SPAG6 by recruiting EIF4A3. As expected, SPAG6 overexpression abrogated inhibition mediated by circMYH9 knockdown on BC cell malignant behaviors. In addition, circMYH9 knockdown inhibited PI3K/Akt signal pathway by increasing PTEN expression in BC cells, while was reversed by SPAG6 upregulation. PTEN inhibition abolished inhibition induced by circMYH9 downregulation on BC malignant progression. Moreover, circMYH9 silencing inhibited tumor growth in mice. CircMYH9 overexpression regulated the PTEN/PI3K/AKT pathway by increasing SPAG6 mRNA stability through recruiting EIF4A3, thereby promoting BC malignant progression.

ABSTRACT To explore SLE staging markers, we analyzed eccDNA in plasma using circular sequencing, comparing healthy controls (HC), active SLE (ASLE), and inactive SLE (ISLE) patients. We found higher eccDNA levels and lower GC content in ASLE and ISLE compared to healthy controls, with a negative correlation between GC content and anti-daDNA, C3, and C4 levels in SLE and HC samples. Differential expression of exon-derived eccGenes in ASLE and ISLE suggests their role in SLE development, with KEGG analysis showing enrichment in SLE-related pathways for these differentially expressed genes. By protein–protein interactions network analysis we found 9 exon-derived eccGenes that were significantly differentially expressed and scored high in both ISLE-HC and ASLE-ISLE as diagnostic criteria for differentiating different disease stages of SLE. In conclusion, the present study reveals that eccDNA length GC content as well as chromosomal distribution in ASLE, ISLE and HC suggests that with eccDNA is associated with the creation of SLE, suggesting GC count of eccDNA as a diagnostic marker for systemic lupus erythematosus. Significant changes in the abundance of eccDNA-related genes from exons such as SOS1, GAD2, BCL11B, PPT1, and GCNT3 were observed in ISLE as compared to ASLE and HC groups and were significantly correlated with SLEDAI-2K. This suggests that these exon-derived eccGenes may play a role in the development and progression of the disease. Consequently, the abundance levels of these exon-derived eccGenes could potentially assist in distinguishing different stages of SLE, beyond a confirmed diagnosis, thus serving as possible biomarkers for the condition.