Aberrant Promoter Methylation Research Articles

Aberrant promoter methylation, expression and function of RASSF1A gene in a series of Italian parathyroid tumors.

Aberrant epigenetic features are key events involved in parathyroid tumorigenesis, including DNA methylation, histone methylation, and non-coding RNAs. Ras Association Domain Family Protein1 Isoform A (RASSF1A) and Adenomatous Polyposis of Colon (APC) are frequently downregulated in human cancers. Here, we investigated their deregulated expression and the potential role in parathyroid neoplasms. methylation of RASSF1A and APC promoters was analyzed in a series of parathyroid adenomas (PAds, n = 80) and parathyroid carcinomas (PCas, n = 9) from Italian patients with primary hyperparathyroidism, RESULTS: RASSF1A and APC promoter methylation occurred in about 90% of PAds samples. PCas displayed RASSF1A promoter methylation, while APC promoter was methylated only in 2 samples. Of note, RASSF1A promoter methylation negatively correlated with PAds tumor size. However, RASSF1A transcript and protein levels were reduced in PAds and PCas compared with parathyroid normal glands. Investigating the potential mechanism involved in RASSF1A promoter methylation, we found that DNA methyltransferases (DNMTs) activity was variable in PAds and inversely correlated with RASSF1A protein levels. In addition, the RASSF1A promoter methylation negatively correlated with long-non-coding Antisense Intronic Noncoding RASSF1A (ANRASSF1A) mRNA levels, excluding the involvement of ANRASSF1 in RASSF1A regulation. In HEK293A cells transfected with the calcium sensing receptor (CASR), loss of RASSF1A increased basal phosphorylated Extracellular signal-regulated kinase (pERK/ERK) levels blunting the CASR-induced increases. RASSF1A and APC promoter methylation is a hallmark of parathyroid tumors; deregulation of DNMTs activity contributes to modulation of RASSF1A expression. Loss of RASSF1A may be involved in the tuning of ERK pathway in parathyroid tumors.

Heterogeneous Transcriptional Landscapes in Human Sporadic Parathyroid Gland Tumors

The expression of several key molecules is altered in parathyroid tumors due to gene mutations, the loss of heterozygosity, and aberrant gene promoter methylation. A set of genes involved in parathyroid tumorigenesis has been investigated in sporadic parathyroid adenomas (PAds). Thirty-two fresh PAd tissue samples surgically removed from patients with primary hyperparathyroidism (PHPT) were collected and profiled for gene, microRNA, and lncRNA expression (n = 27). Based on a gene set including MEN1, CDC73, GCM2, CASR, VDR, CCND1, and CDKN1B, the transcriptomic profiles were analyzed using a cluster analysis. The expression levels of CDC73 and CDKN1B were the main drivers for clusterization. The samples were separated into two main clusters, C1 and C2, with the latter including two subgroups of five PAds (C2A) and nineteen PAds (C2B), both differing from C1 in terms of their lower expression of CDC73 and CDKN1B. The C2A PAd profile was also associated with the loss of TP73, an increased expression of HAR1B, HOXA-AS2, and HOXA-AS3 lncRNAs, and a trend towards more severe PHPT compared to C1 and C2B PAds. C2B PAds were characterized by a general downregulated gene expression. Moreover, CCND1 levels were also reduced as well as the expression of the lncRNAs NEAT1 and VLDLR-AS1. Of note, the deregulated lncRNAs are predicted to interact with the histones H3K4 and H3K27. Patients harboring C2B PAds had lower ionized and total serum calcium levels, lower PTH levels, and smaller tumor sizes than patients harboring C2A PAds. In conclusion, PAds display heterogeneous transcriptomic profiles which may contribute to the modulation of clinical and biochemical features. The general downregulated gene expression, characterizing a subgroup of PAds, suggests the tumor cells behave as quiescent resting cells, while the severity of PHPT may be associated with the loss of p73 and the lncRNA-mediated deregulation of histones.

The Dynamics of Methylation Concentrations in Glutathione Peroxidase 3 Promoter from Patients with Chronic Heart Failure and Their Association with Key Clinical Parameters

ObjectiveThis study investigated changes in methylation concentrations within the glutathione peroxidase 3 (GPX3) promoter region among patients diagnosed with chronic heart failure (CHF). Peripheral blood samples were collected from 20 CHF patients and 20 healthy individuals for analysis. MethodsUsing matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, methylation concentrations of 11 CpG sites within the GPX3 promoter region were quantified. ResultsResults showed a significant increase in methylation at the GPX3_FA10_CpG_24 site in patients with CHF compared with the control group (P < 0.05). Furthermore, a nonlinear dose–response relationship was observed between methylation concentrations at this site and key clinical parameters including serum apolipoprotein A-1, D-dimer, chlorine, potassium, and sodium (Na) (P < 0.05). ConclusionsThese findings suggest that aberrant methylation of the GPX3 promoter may impact disease progression by influencing physiological functions such as blood lipids, coagulation, and electrolytes. Further investigations are warranted to elucidate the role of GPX3 promoter methylation in CHF pathogenesis, potentially contributing valuable insights for its prevention, diagnosis, and treatment.

Abstract B029: Assessing gene expression and methylation of KMT2D and IGF2 genes in patients with non-small cell lung cancer

Abstract Background: Aberrant promoter methylation of CpG islands is an important mechanism for regulation of gene expression. Recent data suggest that epigenetic abnormalities may occur very early in lung carcinogenesis. Systemic methylation changes may be a diagnostic marker for tumor development or prognosis. In this study, the expression and methylation of KMT2D and IGF2 genes were investigated in the lung cancer tissue compared to the adjacent normal tissue. Methods: The status of methylation of KMT2D and IGF2 genes were investigated in 30 patients with NSCLC after genomic DNA extraction using bisulfite treatment and MS-HRM method and the expression of these genes were checked by Real-Time PCR method in same samples. Results: For KMT2D gene, the expression and methylation level increased in 46.6% and 6.67% (respectively) for tumor samples comparison with normal samples (P&amp;gt;0.05). Also, for IGF2 gene 50% tumor samples overexpressed and 50% tumor samples showed that reduced expression comparison with the normal samples (P&amp;gt;0.05). In addition, 96.66% of tumor tissues did not show any change in methylation level for IGF2 gene promoter (P&amp;gt;0.05). Conclusion: This study showed that expression and methylation level of KMT2D and IGF2 genes did not change in NSCLC tumor samples compared to normal samples. However, this study was designed as a pilot study, and further investigations are required to confirm our findings. Citation Format: Arash Matinahmadi, Zoofa Zayani, Seyed Hesamoddin Bidooki, Alireza Tavakolpournegari. Assessing gene expression and methylation of KMT2D and IGF2 genes in patients with non-small cell lung cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Expanding and Translating Cancer Synthetic Vulnerabilities; 2024 Jun 10-13; Montreal, Quebec, Canada. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(6 Suppl):Abstract nr B029.

Mitochondria-Associated Gene SLC25A32 as a Novel Prognostic and Immunotherapy Biomarker: From Pan-Cancer Multiomics Analysis to Breast Cancer Validation.

Mutations in SLC25A32 in humans cause late-onset exercise intolerance, which is associated with various neurological and metabolic diseases. However, its specific mechanism of action in tumour development is poorly understood owing to the lack of multiomics integrated analysis of SLC25A32 in pan-cancer. We used various analytical tools to comprehensively investigate the transcription, protein level, and promoter methylation of SLC25A32. Furthermore, the GSCA and cBioPortal databases were used to evaluate the inheritance impact and epigenetic alterations of SLC25A32 in pan-cancer. SLC25A32 expression and the prognostic significance of copy number alterations in multiple cancers were compared using the UCSCXenaShiny and GEPIA2.0 platforms, and its specific function in breast cancer was experimentally verified. SLC25A32 is abnormally expressed at the transcriptional and protein levels in most cancer types, with aberrant DNA promoter methylation and significant gene amplification in most tumours. SLC25A32 is significantly associated with the survival prognosis of some cancers, immune infiltrating cells, tumour stemness, and immune-related markers. SLC25A32 knockdown decreased breast tumour cell proliferation, invasion, and metastasis. This study aimed to reveal SLC25A32 as a novel prognostic biomarker for pan-cancer prediction and immunotherapy efficacy and specifically describes its underlying mechanism of action in breast cancer. SLC25A32 is widely differentially expressed in pan-cancer with prognostic significance and is correlated with immune infiltration. Additionally, it can affect breast cancer occurrence and development.

Exploring the Diagnostic and Prognostic Predictive Values of Ferroptosis- Related Markers in Lung Adenocarcinoma.

Lung Adenocarcinoma (LUAD), a common and aggressive form of lung cancer, poses significant treatment challenges due to its low survival rates. To better understand the role of ferroptosis driver genes in LUAD, this study aimed to explore their diagnostic and prognostic significance, as well as their impact on treatment approaches and tumor immune function in LUAD. To accomplish the defined goals, a comprehensive methodology incorporating both in silico and wet lab experiments was employed. A comprehensive analysis was conducted on a total of 233 ferroptosis driver genes obtained from the FerrDB database. Utilizing various TCGA databases and the RT-qPCR technique, the expression profiles of 233 genes were examined. Among them, TP53, KRAS, PTEN, and HRAS were identified as hub genes with significant differential expression. Notably, TP53, KRAS, and HRAS exhibited substantial up-regulation, while PTEN demonstrated significant down-regulation at both the mRNA and protein levels in LUAD samples. The dysregulation of hub genes was further associated with poor overall survival in LUAD patients. Additionally, targeted bisulfite-sequencing (bisulfite-seq) analysis revealed aberrant promoter methylation patterns linked to the dysregulation of hub genes. Furthermore, hub genes were found to participate in diverse oncogenic pathways, highlighting their involvement in LUAD tumorigenesis. By leveraging the diagnostic and prognostic potential of ferroptosis driver hub genes (TP53, KRAS, PTEN, and HRAS), significant advancements can be made in the understanding and management of LUAD pathogenesis. Therapeutic targeting of these genes using specific drugs holds great promise for revolutionizing drug discovery and improving the overall survival of LUAD patients.

Genome-wide DNA methylation and transcriptomic patterns of precancerous gastric cardia lesions.

Intestinal metaplasia (IM) and intraepithelial neoplasia (IEN) are considered precursors of gastric cardia cancer (GCC). Here, we investigated the histopathologic and molecular profiles of precancerous gastric cardia lesions (PGCLs) and biomarkers for risk stratification of gastric cardia IM. We conducted a hospital-based evaluation (n = 4578) for PGCL profiles in high-incidence and non-high-incidence regions for GCC in China. We next performed 850K methylation arrays (n = 42) and RNA-seq (n = 44) in tissues with PGCLs. We then examined the protein expression of candidate biomarker using immunohistochemistry. Of the 4578 participants, 791 were diagnosed with PGCLs (600 IM, 62 IM with IEN, and 129 IEN). We found that individuals from high-incidence regions (26.7%) were more likely to develop PGCLs than those from non-high-incidence areas (13.5%). DNA methylation and gene expression alterations, indicated by differentially methylated probes (DMPs) and differentially expressed genes (DEGs), exhibited a progressive increase from type I IM (DMP = 210, DEG = 24), type II IM (DMP = 3402, DEG = 129), to type III IM (DMP = 3735, DEG = 328), peaking in IEN (DMP = 47 373, DEG = 2278). Three DEGs with aberrant promoter methylation were identified, shared exclusively by type III IM and IEN. Of these DEGs, we found that OLFM4 expression appears in IMs and increases remarkably in IENs (P < .001). We highlight that type III IM and IEN share similar epigenetic and transcriptional features in gastric cardia and propose biomarkers with potential utility in risk prediction.

ZNF471 Interacts with BANP to Reduce Tumour Malignancy by Inactivating PI3K/AKT/mTOR Signalling but is Frequently Silenced by Aberrant Promoter Methylation in Renal Cell Carcinoma.

Background: Renal cell carcinoma (RCC) is one of the most common malignant tumours of the urinary system. However, the aetiology and pathogenesis of RCC remain unclear. The C2H2 zinc finger protein (ZNF) family is the largest transcriptional regulatory factor family found in mammals, and Krüppel-associated box domain-containing zinc finger proteins (KRAB-ZFPs) constitute the largest subfamily of the C2H2 zinc finger protein family and play an important role in the occurrence and development of tumours. The aim of this study was to explore the role of abnormal methylation of ZNF471 in the development of renal carcinoma. Methods: In this study, we first used the TCGA and EWAS Data Hub databases to analyse the expression and methylation levels of ZNF471 in renal carcinoma tissues and adjacent normal tissues. Second, we collected samples of renal cancer and adjacent normal tissues at Peking University First Hospital to investigate the expression and methylation level of ZNF471 in renal cancer tissues and the relationships between these levels and the clinicopathological features and prognosis of patients with renal cancer. Next, we investigated the effects of ZNF471 on the proliferation, metastasis, cell cycle progression, and apoptosis of renal cell carcinoma cells by cell biology experiments. Finally, we elucidated the underlying molecular mechanisms of ZNF471 in renal cell carcinoma by transcriptome sequencing, bioinformatics analysis and molecular biology experiments. Results: The expression of ZNF471 in renal carcinoma tissues and cell lines was significantly lower than that in adjacent normal tissues and cell lines due to abnormal promoter CpG methylation. Furthermore, the expression of ZNF471 in renal carcinoma tissues was negatively correlated with tumour stage and grade in patients with renal carcinoma. The results of the cell biology experiments showed that ZNF471 could significantly inhibit the proliferation, migration and cell cycle progression of renal cell carcinoma cells and promote apoptosis in these cells. In addition, ZNF471 could interact with BANP and suppress the malignant phenotype of RCC by inactivating the PI3K/AKT/mTOR signalling pathway. Conclusions: As an important tumour suppressor, ZNF471 can interact with BANP in renal cancer cells and inhibit the activation of the PI3K/AKT/mTOR signalling pathway, thereby inhibiting the occurrence and development of renal cancer.

Methylation of SSTR4 promoter region in multiple mental health disorders.

The existence of a shared genetic basis for mental disorders has long been documented, yet research on whether acquired epigenetic modifications exhibit common alterations across diseases is limited. Previous studies have found that abnormal methylation of cg14631053 at the SSTR4 promoter region mediates the onset of alcohol use disorder. However, whether aberrant methylation of the SSTR4 gene promoter is involved in other mental health disorders remains unclear. In this study, leveraging publicly available data, we identified that changes in methylation of cg14631053 from the SSTR4 promoter region are involved in the development of bipolar disorder and schizophrenia. Furthermore, the direction of methylation changes in the SSTR4 promoter region is disease-specific: hypomethylation is associated with the onset of bipolar disorder and schizophrenia, rather than major depressive disorder. Methylation levels of cg14631053 correlate with chronological age, a correlation that can be disrupted in patients with mental health disorders including schizophrenia and bipolar disorder. In conclusion, SSTR4 promoter methylation may serve as a marker for identifying bipolar disorder and schizophrenia, providing insights into a transdiagnostic mechanism for precision medicine in the future.

Comparative detection of syndecan-2 methylation in preoperative and postoperative stool DNA in patients with colorectal cancer.

Early detection of colorectal cancer (CRC) is essential to reduce cancer-related morbidity and mortality. Stool DNA (sDNA) testing is an emerging method for early CRC detection. Syndecan-2 (SDC2) methylation is a potential biomarker for the sDNA testing. Aberrant DNA methylation is an early epigenetic event during tumorigenesis and can occur in the normal colonic mucosa during aging, which can compromise the sDNA test results. To determine whether methylated SDC2 in sDNA normalizes after surgical resection of CRC. In this prospective study, we enrolled 151 patients with CRC who underwent curative surgical resection between September 2016 and May 2020. Preoperative stool samples were collected from 123 patients and postoperative samples were collected from 122 patients. A total of 104 samples were collected from both preoperative and postoperative patients. Aberrant promoter methylation of SDC2 in sDNA was assessed using linear target enrichment quantitative methylation-specific real-time polymerase chain reaction. Clinicopathological parameters were analyzed using the results of SDC2 methylation. Detection rates of SDC2 methylation in the preoperative and postoperative stool samples were 88.6% and 19.7%, respectively. Large tumor size (3 cm, P = 0.019) and advanced T stage (T3-T4, P = 0.033) were positively associated with the detection rate of SDC2 methylation before surgery. Female sex was associated with false positives after surgery (P = 0.030). Cycle threshold (CT) values were significantly decreased postoperatively compared with preoperative values (P < 0.001). The postoperative negative conversion rate for preoperatively methylated SDC2 was 79.3% (73/92). Our results suggested that the SDC2 methylation test for sDNA has acceptable sensitivity and specificity. However, small size and early T stage tumors are associated with a low detection rate of SDC2 methylation. As the cycle threshold values significantly decreased after surgery, SDC2 methylation test for sDNA might have a diagnostic value for CRC.

Diagnostic performance of RASSF1A and SHOX2 methylation combined with EGFR mutations for differentiation between small pulmonary nodules.

Aberrant methylation of Ras association domain family 1, isoform A (RASSF1A), and short-stature homeobox gene 2 (SHOX2) promoters has been validated as a pair of valuable biomarkers for diagnosing early lung adenocarcinomas (LUADs). Epidermal growth factor receptor (EGFR) is the key driver mutation in lung carcinogenesis. This study aimed to investigate the aberrant promoter methylation of RASSF1A and SHOX2, and the genetic mutation of EGFR in 258 specimens of early LUADs. We retrospectively selected 258 paraffin-embedded samples of pulmonary nodules measuring 2cm or less in diameter and evaluated the diagnostic performance of individual biomarker assays and multiple panels between noninvasive (group 1) and invasive lesions (groups 2A and 2B). Then, we investigated the interaction between genetic and epigenetic alterations. The degree of RASSF1A and SHOX2 promoter methylation and EGFR mutation was significantly higher in invasive lesions than in noninvasive lesions. The three biomarkers distinguished between noninvasive and invasive lesions with reliable sensitivity and specificity: 60.9% sensitivity [95% confidence interval (CI) 52.41-68.78] and 80.0% specificity (95% CI 72.14-86.07). The novel panel biomarkers could further discriminate among three invasive pathological subtypes (area under the curve value > 0.6). The distribution of RASSF1A methylation and EGFR mutation was considerably exclusive in early LUAD (P = 0.002). DNA methylation of RASSF1A and SHOX2 is a pair of promising biomarkers, which may be used in combination with other driver alterations, such as EGFR mutation, to support the differential diagnosis of LUADs, especially for stage I.

Identification of Mir-182-3p/FLI-1 Axis as a Key Signaling in Immune Response in Cervical Cancer: A Comprehensive Bioinformatic Analysis.

To analyze the role of miR-182-3p in CC through a comprehensive bioinformatic analysis. Gene Expression Omnibus (GEO) databases were used for the expression analysis. The mRNA targets of miR-182-3p were identified using miRDB, TargetScanHuman, and miRPathDB. The prediction of island CpG was performed using the MethPrimer program. The transcription factor binding sites in the FLI-1 promoter were identified using ConSite+, Alibaba2, and ALGGEN-PROMO. The protein-protein interaction (PPI) analysis was performed in STRING 11.5. miR-182-3p was significantly overexpressed in CC patients and has potential as a diagnostic. We identified 330 targets of miR-182-3p including FLI-1, which downregulates its expression in CC. Additionally, the aberrant methylation of the FLI-1 promoter and Ap2a transcription factor could be involved in downregulating FLI1 expression. Finally, we found that FLI-1 is a possible key gene in the immune response in CC. The miR-182-3p/FLI-1 axis plays a critical role in immune response in CC.

Aberrant promoter methylation of Wnt inhibitory factor-1 gene is a potential target for treating psoriasis

Psoriasis is a chronic inflammatory skin disease mediated by immune and complex genetic factors. The wingless-related integration site (Wnt) signaling pathway plays a critical role in psoriasis, but how the Wnt pathway is regulated in psoriatic skin and whether it can be exploited for therapeutic benefits is unclear. By comparing biopsies from healthy and psoriatic skin, we found that Wnt inhibitory factor 1 (WIF1), an inhibitor of Wnt signaling, showed reduced expression at both mRNA and protein levels in psoriatic skin. We then quantified methylation of the WIF1 gene promoter by DNA methylation sequencing and found that the WIF1 promoter region was hypermethylated. We further showed that recombinant WIF1 injection ameliorates the imiquimod (IMQ) mouse model of psoriasis. We also revealed that treatment with the DNA methylation inhibitor, decitabine, inhibited proliferation of immortalized human keratinocytes (HaCaT) in a psoriasis-like inflammatory environment. Finally, we applied decitabine to the IMQ mouse model and demonstrated that treatment of mice with decitabine ameliorates the disease. Therefore, our study reveals that methylation of the WIF1 gene is associated with the pathogenesis of psoriasis, and suggests that pharmacological targeting of DNA methylation is a potential treatment strategy for psoriasis.

Porcine Epidemic Diarrhea Virus nsp13 Protein Downregulates Neonatal Fc Receptor Expression by Causing Promoter Hypermethylation through the NF-κB Signaling Pathway.

Porcine epidemic diarrhea virus (PEDV) is a highly pathogenic porcine enteric coronavirus that causes severe watery diarrhea and even death in piglets. The neonatal Fc receptor (FcRn) is the only transport receptor for IgG. FcRn expressed by intestinal epithelial cells can transport IgG from breast milk to piglets to provide immune protection. Previous studies have shown that viral infection affects FcRn expression. In this study, we showed for the first time, to our knowledge, that FcRn expression can be influenced by methyltransferases. In addition, we found that PEDV inhibited FcRn protein synthesis in porcine small intestinal epithelial cells postinfection. Then, we found that PEDV interfered with the transcription of genes through aberrant methylation modification of the FcRn promoter. DNA methyltransferase 3b (DNMT3b) has been implicated in this process. Using a series of PEDV structural and nonstructural protein (nsp) expression plasmids, we showed that nsp13 plays an important role in this aberrant methylation modification. PEDV nsp13 can affect the NF-κB canonical pathway and promote DNMT3b protein expression by facilitating p65 protein binding to chromatin. PEDV caused aberrant methylation of the FcRn promoter via DNMT3b. The same phenomenon was found in animal experiments with large white piglets. IgG transcytosis demonstrated that PEDV nsp13 can inhibit bidirectional IgG transport by FcRn. In addition, the core region of nsp13 (230-597 aa) is critical for FcRn inhibition. Taken together, to our knowledge, our findings revealed a novel immune escape mechanism of PEDV and shed new light on the design and development of vaccines and drugs.

Deciphering key genes involved in cisplatin resistance in kidney renal clear cell carcinoma through a combined in silico and in vitro approach.

The low survival rate of Kidney renal clear cell carcinoma (KIRC) patients is largely attributed to cisplatin resistance. Rather than focusing solely on individual proteins, exploring protein-protein interactions could offer greater insight into drug resistance. To this end, a series of in silico and in vitro experiments were conducted to identify hub genes in the intricate network of cisplatin resistance-related genes in KIRC chemotherapy. The genes involved in cisplatin resistance across KIRC were retrieved from the National Center for Biotechnology Information (NCBI) database using search terms as "Kidney renal clear cell carcinoma" and "Cisplatin resistance". The genes retrieved were analyzed for hub gene identification using the STRING database and Cytoscape tool. Expression and promoter methylation profiling of the hub genes was done using UALCAN, GEPIA, OncoDB, and HPA databases. Mutational, survival, functional enrichment, immune cell infiltration, and drug prediction analyses of the hub genes were performed using the cBioPortal, GEPIA, GSEA, TIMER, and DrugBank databases. Lastly, expression and methylation levels of the hub genes were validated on two cisplatin-resistant RCC cell lines (786-O and A-498) and a normal renal tubular epithelial cell line (HK-2) using two high throughput techniques, including targeted bisulfite sequencing (bisulfite-seq) and RT-qPCR. A total of 124 genes were identified as being associated with cisplatin resistance in KIRC. Out of these genes, MCL1, IGF1R, CCND1, and PTEN were identified as hub genes and were found to have significant (p < 0.05) variations in their mRNA and protein expressions and effects on the overall survival (OS) of the KIRC patients. Moreover, an aberrant promoter methylation pattern was found to be associated with the dysregulation of the hub genes. In addition to this, hub genes were also linked with different cisplatin resistance-causing pathways. Thus, hub genes can be targeted with Alvocidib, Estradiol, Tretinoin, Capsaicin, Dronabinol, Metribolone, Calcitriol, Acetaminophen, Acitretin, Cyclosporine, Azacitidine, Genistein, and Resveratrol drugs. As the pathogenesis of KIRC is complex, targeting hub genes and associated pathways involved in cisplatin resistance could bring a milestone change in the drug discovery and management of drug resistance, which might uplift overall survival among KIRC patients.

Molecular basis of epigenetic regulation in cancer diagnosis and treatment.

The global cancer cases and mortality rates are increasing and demand efficient biomarkers for accurate screening, detection, diagnosis, and prognosis. Recent studies have demonstrated that variations in epigenetic mechanisms like aberrant promoter methylation, altered histone modification and mutations in ATP-dependent chromatin remodelling complexes play an important role in the development of carcinogenic events. However, the influence of other epigenetic alterations in various cancers was confirmed with evolving research and the emergence of high throughput technologies. Therefore, alterations in epigenetic marks may have clinical utility as potential biomarkers for early cancer detection and diagnosis. In this review, an outline of the key epigenetic mechanism(s), and their deregulation in cancer etiology have been discussed to decipher the future prospects in cancer therapeutics including precision medicine. Also, this review attempts to highlight the gaps in epigenetic drug development with emphasis on integrative analysis of epigenetic biomarkers to establish minimally non-invasive biomarkers with clinical applications.

Multiomics to investigate the mechanisms contributing to repression of PTPRC and SOCS2 in pediatric T-ALL: Focus on miR-363-3p and promoter methylation.

T-cell acute lymphoblastic leukemia (T-ALL) is a heterogeneous and aggressive malignancy arising from T-cell precursors. MiRNAs are implicated in negative regulation of gene expression and when aberrantly expressed contribute to various cancer types, including T-ALL. Previously we demonstrated the oncogenic potential of miR-363-3p overexpression in a subgroup of T-ALL patients. Here, using combined proteomic and transcriptomic approaches, we show that miR-363-3p enhances cell growth of T-ALL in vitro via inhibition of PTPRC and SOCS2, which are implicated in repression of the JAK-STAT pathway. We propose that overexpression of miR-363-3p is a novel mechanism potentially contributing to overactivation of JAK-STAT pathway. Additionally, by combining the transcriptomic and methylation data of T-ALL patients, we show that promoter methylation may also contribute to downregulation of SOCS2 expression and thus potentially to JAK-STAT activation. In conclusion, we highlight aberrant miRNA expression and aberrant promoter methylation as mechanisms, alternative to mutations of JAK-STAT-related genes, which might lead to the upregulation of JAK-dependent signaling in T-ALL.

Association between eight hypermethylation-related genes and gastric cancer: a systematic review and meta-analysis.

BackgroundAlthough multiple gene promoter hypermethylation has been associated with gastric carcinogenesis, data on their specific relationship remains scant. We aimed to investigate the correlation between the status of multiple gene promoter methylation and gastric cancer (GC).MethodsWe searched PubMed, EMBASE, CNKI, Wanfang, Cqvip and Cochrane Library up to May 2021. We systematically assessed the association between methylation status of the CpG islands and the risk of GC. We compared the incidence of DNA methylation between tumor and non-tumor tissues, and evaluated the clinicopathological significance of the DNA methylation in gastric carcinoma. The data was presented by an odds ratio (OR) with an accompanying 95% confidence interval (CI). We then generated forest plots calculated by fixed-effects or random-effects model.ResultsThis study enrolled a total of 201 studies (140 papers). Our analysis showed a higher frequency of methylation of the CpG islands in GC tissues compared to non-neoplastic tissues. Besides, the data demonstrated that polygene’s aberrant promoter methylation might be linked to the initial development and progression of GC.DiscussionThe genes with altered DNA methylation might serve as epigenetic biomarkers, providing a promising molecular diagnostic and prognostic tool for human GC. However, our findings need further evaluation in large randomized controlled trials.

HCV Core protein represses DKK3 expression via epigenetic silencing and activates the Wnt/β-catenin signaling pathway during the progression of HCC.

The Wnt/β-catenin signaling pathway is frequently activated in hepatocellular carcinoma (HCC). A number of studies have focused on the aberrant hypermethylation of the DKK family proteins and its role in regulating the activation of specific signaling pathways. However, the exact way by which DKK regulates the signaling pathway caused by Core protein of HCV has not been reported. In the present study, we evaluated the expression level of DKK and its aberrant promoter methylation to investigate the involvement of epigenetic regulation in hepatoma cell lines. The transcription and protein expression of DKK1 was significantly increased, whereas the transcription and protein expression levels of DKK2, DKK3, and DKK4 were significantly decreased following overexpression of Core protein. Pyrosequencing indicated that hypermethylation of DKK3 was increased. This was associated with increased expression of Dnmt1. The investigation of the molecular mechanism indicated that HCV Core protein interacted with Dnmt1, which combined with the promoter of DKK3, leading to methylation of DKK3. Functional studies indicated that Core protein promoted the growth, migration and invasion of cancer cells. However, upregulation of the expression of DKK3 and/or the knockdown of the expression of Dnmt1 inhibited the growth, migration and invasion of cancer cells. Taken together, the data indicated that epigenetic silencing of DKK3 caused by Dnmt1 activated the Wnt/β-catenin pathway in HCV Core-mediated HCC. Therefore, DKK3 may be a potential diagnostic and therapeutic target for HCC.

Epigenetically-regulated miR-30a/c-5p directly target TWF1 and hamper ccRCC cell aggressiveness

Clear cell renal cell carcinoma (ccRCC) is highly prone to metastasize and displays an extremely low 5-year survival rate. Not only miRNAs (miRs) are key gene expression regulators but can also be epigenetically modified. Abnormal miR expression has been linked with epithelial-mesenchymal transition (EMT)-driven ccRCC progression. MiR-30a/c-5p were found downregulated in ccRCC and associated with aggressiveness. Herein, we sought to unravel miR-30a/c-5p mechanistic role in ccRCC. RNA sequencing and genome-wide methylome data of ccRCC and normal tissue samples from The Cancer Genome Atlas database were integrated to identify candidate miRs cytosine-phosphate-guanine (CpG) loci deregulated in ccRCC. TargetScan was searched to identify miR putative targets. MiR-30a/c-5p expression and promoter methylation was evaluated in vitro, by PCR. Western blot, functional and luciferase assays were performed after cell transfection with either pre-miR, antimiR, or siRNA against twinfilin-1 (TWF1). Immunohistochemistry (IHC) was performed in ccRCC tissues. We found miR-30c-5p downregulation and aberrant promoter methylation in ccRCC tissues. In vitro studies revealed concomitant miR-30a/c-5p downregulation and increased promoter methylation, as well as a significant re-expression following decitabine treatment. Functional assays demonstrated that both miRs significantly decreased cell aggressiveness and the protein levels of EMT-promoting players, while upregulating epithelial markers, namely Claudin-1 and ZO-1. Importantly, we confirmed TWF1 as a direct target of both miRs, and its potential involvement in epithelial-mesenchymal transition/mesenchymal-epithelial transition regulation. IHC analysis revealed higher TWF1 expression in primary tissues from patients that developed metastases, after surgical treatment. Our results implicate miR-30a/c-5p in ccRCC cells' aggressiveness attenuation by directly targeting TWF1 and hampering EMT.