Prasanna Kumar Santhekadur

Hepatocellular carcinoma is a leading cause of cancer-related mortality. Several microRNAs play key roles in HCC development and progression. Epigenetic processes, such as DNA methylation, might regulate these RNAs during HCC pathogenesis. In this study, we show that the miR-379/656 cluster/C14MC acts as a tumor suppressor cluster and is epigenetically regulated by DNA methylation. C14MC miRNA expression was determined in HCC cell lines using the nCounter assay and from the TCGA-LIHC clinical cohort. C14MC putative promoter was identified, characterized using cloning and luciferase assay, and the methylation status of promoter-bound CpGs was determined using bisulfite Sanger sequencing. The expressions of C14MC targets were experimentally validated by transcriptomic sequencing or transfecting mimics, followed by qRT-PCR. Furthermore, the diagnostic and prognostic significance of C14MC and its target interactome in HCC was assessed using clinical data from the TCGA-LIHC cohort. C14MC was downregulated in HCC cell lines and in TCGA-LIHC. The loss of C14MC tumor suppressor function was directly regulated by the hypermethylation of promoter-CpGs. Reactivating specific C14MC miRNAs, such as miR-299-5p and miR-376c-3p via mimics, abrogated the expression of several target oncogenes, including PARP1, SPP1, RAD21, and CENPA, which regulate critical molecular pathways such as the p53 signaling and NF-κB signaling pathways in HCC. Additionally, overexpressing these miRNAs inhibited HCC cell migration and invasion. Also, C14MC and its target interactome exhibited significant clinical correlation in terms of survival outcomes of HCC patients. This is the first study to show that C14MC is a methylation-dependent cluster in HCC. Several of these miRNAs and their targets can be used for early HCC diagnosis and prognosis. Thus, targeting C14MC can be useful in HCC management.

Central obesity is one of the defining features of metabolic syndrome (MetS). MetS comprises a cluster of metabolic disturbances including insulin resistance (IR), hypertension, and altered glucose, lipid, and fatty acid metabolism. These alterations are characterized by reduced levels of high-density lipoprotein (HDL) commonly referred to as “good cholesterol” and increased levels of low-density lipoprotein (LDL) or “bad cholesterol”. While HDL protects against cardiovascular disease (CVD), elevated LDL increases disease risk. Collectively, these metabolic abnormalities raise the risk of developing type-2 diabetes (T2D), metabolic dysfunction-associated steatohepatitis (MASH), and CVDs. The raising global incidence of MetS is largely attributed to sedentary lifestyles, westernization, and the consumption of energy-dense processed foods, making it a growing public health concern across the globe. In recent years microRNAs (miRNAs), which are small non-coding RNA molecules (18 to 25 nucleotides), have emerged as important regulators of post-transcriptional gene expression in metabolic and inflammatory pathways. Among these, miR-155 have received considerable attention for its role in immune activation, inflammatory signalling, cancer, and energy balance. MiR-155 modulates key genes involved in insulin signalling, glucose metabolism, and metabolic homeostasis, thereby contributing to overall metabolic control. Given these roles, circulating miR-155 has arisen as a promising non-invasive biomarker for metabolic abnormalities and a potential therapeutic target in MetS. This review highlights the multifaceted roles of miR-155 and summarizes accumulating evidence supporting its central involvement in the physiological and pathological mechanisms underlying MetS, with implications for early diagnosis and therapeutic development.

Introduction: Oral diseases such as caries and periodontitis are complex, multifactorial diseases and remain the most prevalent worldwide. Both diseases are associated with vitamin D deficiency (VDD) and its pathophysiological process. The prevalence of metabolic syndrome (MetS) is rising in developing countries, and studies have shown that oral diseases are more prevalent among the metabolic group. This study aims to assess and correlate the relationship between serum vitamin D levels, salivary antimicrobial peptides (AMPs), and their role in oral health. Materials and methods: A total of 80 individuals aged 35–75 years were recruited, including 40 patients in the metabolic syndrome group, following the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) criteria, and 40 in the non-metabolic group. Serum vitamin D levels and salivary AMPs were estimated using enzyme-linked immunosorbent assay (ELISA). Oral health status was assessed using the Decayed, Missing, Filled Teeth (DMFT) index and by recording the presence or absence of periodontal pockets. The data obtained were subjected to statistical analysis to determine correlations between systemic status, biochemical markers, and oral health parameters. Results: The Mann–Whitney U test was applied to compare continuous variables between the metabolic and non-metabolic groups, as well as between subgroups. The chi-squared test was applied to assess associations between categorical variables. Patients with metabolic syndrome exhibited reduced serum vitamin D levels, although differences were not statistically significant. Salivary β-defensin and cathelicidin levels were relatively higher in the metabolic group, but without significant intergroup variation. A higher DMFT score and greater prevalence of periodontal pockets were recorded among metabolic syndrome patients compared with non-metabolic individuals. Conclusions: Within the study's limitations, a potential link between metabolic syndrome and compromised oral health was observed, as demonstrated by increased caries incidence and periodontal involvement. While variations in serum vitamin D and salivary AMPs did not achieve statistical significance, the findings suggest an altered host defense mechanism in metabolic syndrome patients. Larger, longitudinal studies are required to further elucidate these associations and emphasize the importance of routine oral screening in individuals with metabolic disorders, and the implementation of oral health polices is mandatory to maintain good oral health and well-being among both metabolic and non-metabolic populations.

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality. Several microRNAs (miRNAs) play key roles in HCC development and progression. The role of epigenetic processes like DNA methylation in the regulation of miRNAs is critical to HCC pathogenesis. In this study, we show that the miR-379/656 cluster (C14MC) acts as a tumor suppressor cluster and is epigenetically regulated by DNA methylation. We demonstrated that C14MC is downregulated in HCC cell lines through nCounter assay and in clinical samples from The Cancer Genome Atlas (TCGA) liver hepatocellular carcinoma tissues. The C14MC promoter was identified and characterized through cloning and dual luciferase assay. Furthermore, we demonstrated that the loss of C14MC tumor suppressor function is directly regulated by the hypermethylation of promoter-bound CpGs, as shown in artificial methylation experiments. The reactivation of specific C14MC miRNAs, like miR-299-5p and miR-376c-3p via mimics, abrogated the expression of several target oncogenes, including PARP1, SPP1, RAD21, and CENPA that regulate critical molecular pathways such as the p53 signaling and NF-kappa B signaling pathways in HCC. Additionally, overexpression of miR-299-5p and miR-376c-3p inhibited HCC cell migration and invasion, suggesting that overexpression of candidate C14MC miRNAs can mitigate cancer hallmarks in HCC cells. Furthermore, we checked for the clinical correlation of C14MC targets and their target genes in terms of survival outcomes and identified the key genes associated with prognostic potential in HCC. We conclude from our experimental findings that C14MC is a tumor-suppressor miRNA cluster and is regulated epigenetically by methylation in HCC. Several of these miRNAs and their targets can be used for early HCC diagnosis and prognosis. Thus, targeting C14MC can be useful in HCC management.

The lack of reliable early markers specific to hepatocellular carcinoma (HCC) limits its effective management. While the genetic factors defining this disease are largely understood, the epigenetic mechanisms that cause HCC remain elusive. MicroRNAs (miRNAs) operate as polycistronic clusters rather than individual genes and are critical to the development and progression of multiple cancers, including HCC. In this study, we identified several miRNA clusters, including the miR-106b/25 cluster (miR-106b-5p, miR-25-3p, and miR-93-5p), that are overexpressed in HCC cells, suggesting their oncogenic function. We then performed whole-transcriptomic sequencing and identified gene targets of this cluster, namely, CAV1, DNAJB4, PTPRD, MFSD2A, TCF4, KLF6, MCC, CYB5A, ESR2, NR4A3, PRKCB, RASSF2, TXNIP, and SOD2, to be downregulated in the HCC spheroids and clinical datasets. Further, gene enrichment analysis revealed associations with critical pathways, such as Wnt signaling, TGF-beta signaling, VEGFA-VEGFR2 signaling, and EGF/R signaling pathways. Furthermore, survival analysis revealed that miR-93-5p (HR = 0.72, p = 0.0246), HCC stage (HR = 2.43, p = 0.0000113), TCF4 (HR = 0.66, p = 0.0106), DNAJB4 (HR = 1.29, p = 0.0214), MCC (HR = 1.35, p = 0.0268), and CYB5A (HR = 0.77, p = 0.0423) affect overall survival (OS). Finally, a combined prognostic model for the miRNA cluster and its target genes via the random forest approach revealed that the miR-106b/25 cluster and its interactome are significantly associated with OS (p < 0.0001), thereby providing a comprehensive understanding of the cluster and its targets in the development and progression of HCC and its use as a potential marker for HCC.

The liver is the largest internal organ. Several critical functions are attributed to the liver which include metabolism, synthesis of serum proteins, excretion, detoxification, and various physiological processes essential for maintaining body homeostasis. Its unique regenerative capacity helps the liver to restore itself fully after injury. This process involves all hepatocytes with or without the involvement of stem cells. The function of the liver is known to be regulated by circadian rhythm, which includes feeding-fasting cycles and the maintenance of the suprachiasmatic nucleus (SCN) that regulates as a master clock. The normal functioning of the liver is critical to the overall maintenance of homeostasis as it serves as a peripheral clock, suggesting a potential link between the SCN and liver. Aberrations in these circadian rhythms have been linked to various chronic hepatic diseases such as metabolic dysfunction-associated steatotic liver disease (MASLD), which can lead to Hepatocellular carcinoma (HCC). This mini review explores the significance of circadian rhythm in liver function, with a focus on the role of melatonin and nuclear receptors such as Retinoic acid receptor-related orphan receptor-alpha (RORα), which is a known melatonin receptor critical to sustaining these rhythms that can influence biological functions, including immune system functioning, cell growth, and differentiation. Further, RORα is identified as one of the key regulators of inflammation and acts as a potential tumor suppressor, particularly in the context of HCC. This review explores the interplay between RORα, melatonin, and circadian rhythm and discusses the underpinnings that offer insights into the role of circadian rhythm disruption in HCC development and novel therapeutic strategies targeting circadian rhythm modulations to mitigate HCC.