scholarly journals Thymoquinone Is a Multitarget Single Epidrug That Inhibits the UHRF1 Protein Complex

Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 622
Author(s):  
Omeima Abdullah ◽  
Ziad Omran ◽  
Salman Hosawi ◽  
Ali Hamiche ◽  
Christian Bronner ◽  
...  

Silencing of tumor suppressor genes (TSGs) through epigenetic mechanisms, mainly via abnormal promoter DNA methylation, is considered a main mechanism of tumorigenesis. The abnormal DNA methylation profiles are transmitted from the cancer mother cell to the daughter cells through the involvement of a macromolecular complex in which the ubiquitin-like containing plant homeodomain (PHD), and an interesting new gene (RING) finger domains 1 (UHRF1), play the role of conductor. Indeed, UHRF1 interacts with epigenetic writers, such as DNA methyltransferase 1 (DNMT1), histone methyltransferase G9a, erasers like histone deacetylase 1 (HDAC1), and functions as a hub protein. Thus, targeting UHRF1 and/or its partners is a promising strategy for epigenetic cancer therapy. The natural compound thymoquinone (TQ) exhibits anticancer activities by targeting several cellular signaling pathways, including those involving UHRF1. In this review, we highlight TQ as a potential multitarget single epidrug that functions by targeting the UHRF1/DNMT1/HDAC1/G9a complex. We also speculate on the possibility that TQ might specifically target UHRF1, with subsequent regulatory effects on other partners.

2003 ◽  
Vol 23 (1) ◽  
pp. 206-215 ◽  
Author(s):  
Yutaka Kondo ◽  
LanLan Shen ◽  
Jean-Pierre J. Issa

ABSTRACT The mechanism of DNA hypermethylation-associated tumor suppressor gene silencing in cancer remains incompletely understood. Here, we show by chromatin immunoprecipitation that for three genes (P16, MLH1, and the O 6-methylguanine-DNA methyltransferase gene, MGMT), histone H3 Lys-9 methylation directly correlates and histone H3 Lys-9 acetylation inversely correlates with DNA methylation in three neoplastic cell lines. Treatment with the histone deacetylase inhibitor trichostatin A (TSA) resulted in moderately increased Lys-9 acetylation at silenced loci with no effect on Lys-9 methylation and minimal effects on gene expression. By contrast, treatment with the DNA methyltransferase inhibitor 5-aza-2′-deoxycytidine (5Aza-dC) rapidly reduced Lys-9 methylation at silenced loci and resulted in reactivation for all three genes. Combined treatment with 5Aza-dC and TSA was synergistic in reactivating gene expression through simultaneous effects on Lys-9 methylation and acetylation, which resulted in a robust increase in the ratio of Lys-9 acetylated and methylated histones at loci showing dense DNA methylation. By contrast to Lys-9, histone H3 Lys-4 methylation inversely correlated with promoter DNA methylation, was not affected by TSA, and was increased moderately at silenced loci by 5Aza-dC. Our results suggest that reduced H3 Lys-4 methylation and increased H3 Lys-9 methylation play a critical role in the maintenance of promoter DNA methylation-associated gene silencing in colorectal cancer.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jianfeng Xu ◽  
Jiejun Shi ◽  
Xiaodong Cui ◽  
Ya Cui ◽  
Jingyi Jessica Li ◽  
...  

AbstractPromoter DNA methylation is a well-established mechanism of transcription repression, though its global correlation with gene expression is weak. This weak correlation can be attributed to the failure of current methylation quantification methods to consider the heterogeneity among sequenced bulk cells. Here, we introduce Cell Heterogeneity–Adjusted cLonal Methylation (CHALM) as a methylation quantification method. CHALM improves understanding of the functional consequences of DNA methylation, including its correlations with gene expression and H3K4me3. When applied to different methylation datasets, the CHALM method enables detection of differentially methylated genes that exhibit distinct biological functions supporting underlying mechanisms.


2010 ◽  
Vol 42 (12) ◽  
pp. 1093-1100 ◽  
Author(s):  
Julie Borgel ◽  
Sylvain Guibert ◽  
Yufeng Li ◽  
Hatsune Chiba ◽  
Dirk Schübeler ◽  
...  

Genes ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 172 ◽  
Author(s):  
Hemant Gujar ◽  
Daniel Weisenberger ◽  
Gangning Liang

A DNA sequence is the hard copy of the human genome and it is a driving force in determining the physiological processes in an organism. Concurrently, the chemical modification of the genome and its related histone proteins is dynamically involved in regulating physiological processes and diseases, which overall constitutes the epigenome network. Among the various forms of epigenetic modifications, DNA methylation at the C-5 position of cytosine in the cytosine–guanine (CpG) dinucleotide is one of the most well studied epigenetic modifications. DNA methyltransferases (DNMTs) are a family of enzymes involved in generating and maintaining CpG methylation across the genome. In mammalian systems, DNA methylation is performed by DNMT1 and DNMT3s (DNMT3A and 3B). DNMT1 is predominantly involved in the maintenance of DNA methylation during cell division, while DNMT3s are involved in establishing de novo cytosine methylation and maintenance in both embryonic and somatic cells. In general, all DNMTs require accessory proteins, such as ubiquitin-like containing plant homeodomain (PHD) and really interesting new gene (RING) finger domain 1 (UHRF1) or DNMT3-like (DNMT3L), for their biological function. This review mainly focuses on the role of DNMT3B and its isoforms in de novo methylation and maintenance of DNA methylation, especially with respect to their role as an accessory protein.


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