dna hypermethylation
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2022 ◽  
Vol 11 (2) ◽  
pp. 398
Author(s):  
Vikash Kansal ◽  
Anshu Agarwal ◽  
Angela Harbour ◽  
Humaira Farooqi ◽  
Vijay Kumar Singh ◽  
...  

Previously, we and others have shown that the regular intake of green tea polyphenols (GTPs) reduces ultraviolet B (UVB) radiation-induced skin cancer by targeting multiple signaling pathways, including DNA damage, DNA repair, immunosuppression, and inflammation. Here, we determine the effect of GTPs on UVB-induced epigenetic changes, emphasizing DNA hypermethylation in UV-exposed skin and tumors and their association with miR-29, a key regulator of DNA methyltransferases (DNMTs). Skin cancer was induced in SKH-1 hairless mice following repeated exposures of UVB radiation (180 mJ/cm2, three times/week, 24 weeks) with or without GTPs supplementation (0.2%) in drinking water. Regular intake of GTPs inhibited tumor growth by hindering the cascade of DNA hypermethylation events. GTPs supplementation significantly blocked UVB-induced DNA hypermethylation in the skin (up to 35%; p < 0.0001) and in tumors (up to 50%; p < 0.0001). Experimental results showed that the levels of DNA hypermethylation were higher in GTPs-treated mice than in the control group. The expressions of miR-29a, miR-29b, and miR-29c were markedly decreased in UV-induced skin tumors, and GTPs administration blocked UVB-induced miR-29s depletion. Furthermore, these observations were verified using the in vitro approach in human skin cancer cells (A431) followed by treatment with GTPs or mimics of miR-29c. Increased levels of miR-29 were observed in GTPs-treated A431 cells, resulting in increased TET activity and decreased DNA hypermethylation. In conclusion, UVB-mediated miR-29 depletion promotes DNA hypermethylation and leads to enhanced tumor growth by silencing tumor suppressors. Regular intake of GTPs rescued UVB-induced miR-29 depletion and prevented tumor growth by maintaining reduced DNA hypermethylation and activating tumor suppressors. Our observations suggest that miR-based strategies and regular consumption of GTPs could minimize the risk of UVB-induced skin cancers and contribute to better management of NMSCs.


2022 ◽  
Vol 8 ◽  
Author(s):  
Bo Ma ◽  
Zaoqu Liu ◽  
Hui Xu ◽  
Long Liu ◽  
Tao Huang ◽  
...  

Background: Aldehyde dehydrogenase 2 (ALDH2) is well-known to be a key enzyme in alcohol metabolism. However, a comprehensive understanding of ALDH2 across human cancers is lacking.Methods: A systematic and comprehensive analysis of the molecular alterations and clinical relevance for ALDH2 in more than 10,000 samples from 33 cancer types was performed. qRT-PCR was performed on 60 cancer and 60 paired nontumor tissues.Results: It was observed that ALDH2 was generally downregulated in most cancers, which was mainly driven by DNA hypermethylation rather than mutations or copy number variations. Besides, ALDH2 was closely related to the inhibition and activation of tumor pathways and a variety of potential targeted agents had been discovered in our research. Last but not least, ALDH2 had the best prediction efficacy in assessing immunotherapeutic response compared with PD-L1, PD-1, CTLA4, CD8, and tumor mutation burden (TMB) in cutaneous melanoma. According to the analysis of large-scale public data and 60 pairs of clinical cancer samples, we found the downregulation of ALDH2 expression tends to suggest the malignant phenotypes and adverse prognosis, which might enhance the precise diagnosis and timely intervention of cancer patients.Conclusion: This study advanced the understanding of ALDH2 across cancers, and provided important insight into chemotherapy, immunotherapy and prognosis of patients with cancer.


2022 ◽  
Vol 2022 ◽  
pp. 1-9
Author(s):  
Jiabei Xie ◽  
Lin Fu ◽  
Jianmin Zhang

Stomach cancer is the second largest cause of cancer-related mortality globally, and it continues to be a reason for worry today. Inhalation of the stomach cancer risk factor H. pylori produces large levels of reactive oxygen species (ROS). When combined with glutathione reductase, glutathione peroxidase 3 (GPX3) catalyzes the reduction of hydrogen peroxide and lipid peroxides. To get a better understanding of the GPX3 gene’s role in the illness, the researchers used quantitative real-time RT-PCR to examine the gene’s expression and regulation in gastric cancer cell lines, original gastric cancer samples, and 45 normal stomach mucosa adjacent to malignancies. According to the research, GPX3 expression was decreased or silenced in eight of nine cancer cell lines and 83 percent of gastric cancer samples (90/108) as compared to normal gastric tissues in the vicinity of the tumor ( P < 0.0001 ). It was found that 60 percent of stomach cancer samples exhibited DNA hypermethylation after analyzing the GPX3 promoter ( P = 0.007 ) (a methylation level of more than 10 percent, as measured by bisulfite pyrosequencing). In stomach tumors, we found a statistically significant reduction in the amount of GPX3 DNA copies ( P < 0.001 ). The gene expression of SNU1 and MKN28 cells was restored after treatment with 5-Aza-2′ Deoxycytidine to reduce GPX3 promoter methylation. Genetic and epigenetic alterations lead GPX3 to be dysfunctional in gastric cancer. This indicates that the systems that regulate ROS have been disrupted, and GPX3 may be implicated in the development of gastric cancer, as shown by our results when evaluated alone and in combination.


Author(s):  
Funsho J Ogunshola ◽  
Werner Smidt ◽  
Anneta F Naidoo ◽  
Thandeka Prudence Nkosi ◽  
Thandekile Ngubane ◽  
...  

CD8+ T-cells play an important role in HIV control. However, in human lymph nodes (LNs), only a small subset of CD8+ T-cells expresses CXCR5, the chemokine receptor required for cell migration into B cell follicles, which are major sanctuaries for HIV persistence in individuals on therapy. Here, we investigate the impact of HIV infection on follicular CD8+ T-cells (fCD8s) frequencies, trafficking pattern and CXCR5 regulation. We show that, although HIV infection results in a marginal increase of fCD8s in LN, the majority of HIV-specific CD8+ T-cells are CXCR5 negative (non-fCD8s) (p&lt;0.003). Mechanistic investigations using ATAC-seq showed that non-fCD8s have closed chromatin at the CXCR5 transcriptional start site (TSS). DNA bisulfite sequencing identified DNA hypermethylation at the CXCR5 TSS as the most probable cause of closed chromatin. Transcriptional factor footprints analysis revealed enrichment of transforming growth factors (TGFs) at the TSS of fCD8s. In-vitro stimulation of non-fCD8s with recombinant TGF-β resulted in significant increase in CXCR5 expression (fCD8s). Thus, this study identifies TGF-β signaling as a viable strategy for increasing fCD8s frequencies in follicular areas of the LN where they are needed to eliminate HIV infected cells, with implications for HIV cure strategies.


Epigenetics ◽  
2022 ◽  
pp. 1-10
Author(s):  
Natália Birknerová ◽  
Helena Kovaříková ◽  
Ivana Baranová ◽  
Albína Přikrylová ◽  
Jan Laco ◽  
...  

2022 ◽  
Vol 11 ◽  
Author(s):  
Xuemin Zhong ◽  
Yanping Yang ◽  
Bo Li ◽  
Pan Liang ◽  
Yiying Huang ◽  
...  

Lipid is the building block and an important source of energy, contributing to the malignant behavior of tumor cells. Recent studies suggested that lipid droplets (LDs) accumulations were associated with nasopharyngeal carcinoma (NPC) progression. Solute carrier family 27 member 6 (SLC27A6) mediates the cellular uptake of long-chain fatty acid (LCFA), a necessary lipid component. However, the functions of SLC27A6 in NPC remain unknown. Here, we found a significant reduction of SLC27A6 mRNA in NPC tissues compared with normal nasopharyngeal epithelia (NNE). The promoter methylation ratio of SLC27A6 was greater in NPC than in non-cancerous tissues. The demethylation reagent 5-aza-2’-deoxycytidine (5-aza-dC) remarkably restored the mRNA expression of SLC27A6, suggesting that this gene was downregulated in NPC owing to DNA promoter hypermethylation. Furthermore, SLC27A6 overexpression level in NPC cell lines led to significant suppression of cell proliferation, clonogenicity in vitro, and tumorigenesis in vivo. Higher SLC27A6 expression, on the other hand, promoted NPC cell migration and invasion. In particular, re-expression of SLC27A6 faciliated epithelial-mesenchymal transition (EMT) signals in xenograft tumors. Furthermore, we observed that SLC27A6 enhanced the intracellular amount of triglyceride (TG) and total cholesterol (T-CHO) in NPC cells, contributing to lipid biosynthesis and increasing metastatic potential. Notably, the mRNA level of SLC27A6 was positively correlated with cancer stem cell (CSC) markers, CD24 and CD44. In summary, DNA promoter hypermethylation downregulated the expression of SLC27A6. Furthermore, re-expression of SLC27A6 inhibited the growth capacity of NPC cells but strengthened the CSC markers. Our findings revealed the dual role of SLC27A6 in NPC and shed novel light on the link between lipid metabolism and CSC maintenance.


2022 ◽  
Vol 2 (1) ◽  
pp. 1-9
Author(s):  
Lucas A. Salas ◽  
Thomas G. Stewart ◽  
Bret C. Mobley ◽  
Chengwei Peng ◽  
Jing Liu ◽  
...  

Isocitrate dehydrogenase (IDH) mutations in low-grade gliomas (LGG) result in improved survival and DNA hypermethylation compared with IDH wild-type LGGs. IDH-mutant LGGs become hypomethylated during progression. It is uncertain whether methylation changes occur during IDH wild-type GBM progression and whether the methylome can be reprogrammed. This phase I study evaluated the safety, tolerability, efficacy, and methylome changes after l-methylfolate (LMF) treatment, in combination with temozolomide and bevacizumab in patients with recurrent high-grade glioma. Fourteen patients total, 13 with GBM, one with anaplastic astrocytoma, all IDH wild-type were enrolled in the study. All patients received LMF at either 15, 30, 60, or 90 mg daily plus temozolomide (75 mg/m2 5 days per month) and bevacizumab (10 mg/kg every two weeks).No MTD was identified. LMF-treated patients had median overall survival of 9.5 months [95% confidence interval (CI), 9.1–35.4] comparable with bevacizumab historical control 8.6 months (95% CI, 6.8–10.8). Six patients treated with LMF survived more than 650 days. Across all treatment doses, the most adverse events were diarrhea (7%, 1 patient, grade 2), reflux (7%, 1 patient, grade 2), and dysgeusia (7%, 1 patient, grade 2). In the six brains donated at death, there was a 25% increase in DNA methylated CpGs compared with the paired initial tumor. LMF in combination with temozolomide and bevacizumab was well tolerated in patients with recurrent IDH wild-type high-grade glioma. This small study did not establish a superior efficacy with addition of LMF compared with standard bevacizumab therapy; however, this study did show methylome reprogramming in high-grade glioma. Significance: Glioblastoma (GBM) is a primary brain tumor with a poor prognosis. Therapies to date have failed to improve survival. LGGs, with IDH mutations, have increased global DNA methylation and increased survival compared with GBMs. GBMs lack this mutation and have less DNA methylation. Here we show that the DNA methylome can be modified in GBM with LMF. Such treatment might be useful in methylome priming prior to immunotherapy.


2021 ◽  
Author(s):  
Cleandra Gregório ◽  
Shefali Thakur ◽  
Raquel Camara Rivero ◽  
Simone Márcia dos Santos Machado ◽  
Cyrille Cuenin ◽  
...  

Abstract Genetic and epigenetic alterations of the telomere maintenance machinery like telomere length and telomerase reverse transcriptase (encoded by TERT gene) are reported in several human malignancies. However, there is limited knowledge on the status of the telomere machinery in periampullary carcinomas (PAC) that are rare and heterogeneous groups of cancers arising from different anatomic sites around the ampulla of Vater. In the current study, we investigated the relative telomere length (RTL) and the most frequent genetic and epigenetic alterations in the TERT promoter in PAC (n=20) and compared with tumor-adjacent nonpathological duodenum (NDu; n=16). We found shorter RTLs (1.27 vs 1.33, P=0.01) and lower TERT protein expression (p=0.04) in PAC tissues as compared to the NDu. Although we did not find any mutation at two reactivating hotspot mutation sites of the TERT promoter, we detected polymorphism in 55% (11/20) of the cases at rs2853669 (T>C). Also, we found a hypermethylated region in the TERT promoter of PACs consisting of four CpGs (cg10896616 with ∆β 7%; cg02545192 with ∆β 9%; cg03323598 with ∆β 19%; and cg07285213 with ∆β 15%). In conclusion, we identified shorter telomeres with DNA hypermethylation in the TERT promoter region and lower TERT protein expression in PAC tissues. Further studies with a larger sample size are necessary to substantiate these results.


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