scholarly journals Chromatin Regulator SPEN/SHARP in X Inactivation and Disease

Cancers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1665
Author(s):  
Benedetto Daniele Giaimo ◽  
Teresa Robert-Finestra ◽  
Franz Oswald ◽  
Joost Gribnau ◽  
Tilman Borggrefe

Enzymes, such as histone methyltransferases and demethylases, histone acetyltransferases and deacetylases, and DNA methyltransferases are known as epigenetic modifiers that are often implicated in tumorigenesis and disease. One of the best-studied chromatin-based mechanism is X chromosome inactivation (XCI), a process that establishes facultative heterochromatin on only one X chromosome in females and establishes the right dosage of gene expression. The specificity factor for this process is the long non-coding RNA Xinactivespecifictranscript (Xist), which is upregulated from one X chromosome in female cells. Subsequently, Xist is bound by the corepressor SHARP/SPEN, recruiting and/or activating histone deacetylases (HDACs), leading to the loss of active chromatin marks such as H3K27ac. In addition, polycomb complexes PRC1 and PRC2 establish wide-spread accumulation of H3K27me3 and H2AK119ub1 chromatin marks. The lack of active marks and establishment of repressive marks set the stage for DNA methyltransferases (DNMTs) to stably silence the X chromosome. Here, we will review the recent advances in understanding the molecular mechanisms of how heterochromatin formation is established and put this into the context of carcinogenesis and disease.

Antioxidants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 865 ◽  
Author(s):  
Shamee Bhattacharjee ◽  
Roderick H. Dashwood

Epigenetics has provided a new dimension to our understanding of nuclear factor erythroid 2–related factor 2/Kelch-like ECH-associated protein 1 (human NRF2/KEAP1 and murine Nrf2/Keap1) signaling. Unlike the genetic changes affecting DNA sequence, the reversible nature of epigenetic alterations provides an attractive avenue for cancer interception. Thus, targeting epigenetic mechanisms in the corresponding signaling networks represents an enticing strategy for therapeutic intervention with dietary phytochemicals acting at transcriptional, post-transcriptional, and post-translational levels. This regulation involves the interplay of histone modifications and DNA methylation states in the human NFE2L2/KEAP1 and murine Nfe2l2/Keap1 genes, acetylation of lysine residues in NRF2 and Nrf2, interaction with bromodomain and extraterminal domain (BET) acetyl “reader” proteins, and non-coding RNAs such as microRNA (miRNA) and long non-coding RNA (lncRNA). Phytochemicals documented to modulate NRF2 signaling act by reversing hypermethylated states in the CpG islands of NFE2L2 or Nfe2l2, via the inhibition of DNA methyltransferases (DNMTs) and histone deacetylases (HDACs), through the induction of ten-eleven translocation (TET) enzymes, or by inducing miRNA to target the 3′-UTR of the corresponding mRNA transcripts. To date, fewer than twenty phytochemicals have been reported as NRF2 epigenetic modifiers, including curcumin, sulforaphane, resveratrol, reserpine, and ursolic acid. This opens avenues for exploring additional dietary phytochemicals that regulate the human epigenome, and the potential for novel strategies to target NRF2 signaling with a view to beneficial interception of cancer and other chronic diseases.


2021 ◽  
Vol 11 (6) ◽  
pp. 513
Author(s):  
Zheng Zhang ◽  
Meng Gu ◽  
Zhongze Gu ◽  
Yan-Ru Lou

Genetic polymorphisms are defined as the presence of two or more different alleles in the same locus, with a frequency higher than 1% in the population. Since the discovery of long non-coding RNAs (lncRNAs), which refer to a non-coding RNA with a length of more than 200 nucleotides, their biological roles have been increasingly revealed in recent years. They regulate many cellular processes, from pluripotency to cancer. Interestingly, abnormal expression or dysfunction of lncRNAs is closely related to the occurrence of human diseases, including cancer and degenerative neurological diseases. Particularly, their polymorphisms have been found to be associated with altered drug response and/or drug toxicity in cancer treatment. However, molecular mechanisms are not yet fully elucidated, which are expected to be discovered by detailed studies of RNA–protein, RNA–DNA, and RNA–lipid interactions. In conclusion, lncRNAs polymorphisms may become biomarkers for predicting the response to chemotherapy in cancer patients. Here we review and discuss how gene polymorphisms of lncRNAs affect cancer chemotherapeutic response. This knowledge may pave the way to personalized oncology treatments.


2021 ◽  
Vol 27 ◽  
Author(s):  
Wen Xu ◽  
Bei Wang ◽  
Yuxuan Cai ◽  
Jinlan Chen ◽  
Xing Lv ◽  
...  

Background: Long non-coding RNAs (lncRNA) have been identified as novel molecular regulators in cancers. LncRNA ADAMTS9-AS2 can mediate the occurrence and development of cancer through various ways such as regulating miRNAs, activating the classical signaling pathways in cancer, and so on, which have been studied by many scholars. In this review, we summarize the molecular mechanisms of ADAMTS9-AS2 in different human cancers. Methods: Through a systematic search of PubMed, lncRNA ADAMTS9-AS2 mediated molecular mechanisms in cancer are summarized inductively. Results: ADAMTS9-AS2 aberrantly expression in different cancers is closely related to cancer proliferation, invasion, migration, inhibition of apoptosis. The involvement of ADAMTS9-AS2 in DNA methylation, mediating PI3K / Akt / mTOR signaling pathways, regulating miRNAs and proteins, and such shows its significant potential as a therapeutic cancer target. Conclusion: LncRNA ADAMTS9-AS2 can become a promising biomolecular marker and a therapeutic target for human cancer.


2021 ◽  
Author(s):  
hafiza sobia ramzan ◽  
Kashif Aziz Ahmad

Background: Osteoarthritis (OA) is a common disease of the joints among old populace until today. The treatment possibilities and roles of miRNA and long non-coding RNA (lncRNA) in therapy of OA has previously been explored. However, the functional roles of Long noncoding RNA KCNQ1OT1 and miRNA let-7a-5p on Osteoarthritis development and progression remains unclear. This study aimed at investigating the influence of KCNQ1OT1 on let-7a-5p in moderation of OA development and advancement. Materials and Methods: RT-qPCR examined expression of KCNQ1OT1and let-7a-5p in cultured human primary chondrocyte cell lines. Cell transfection overexpressed or knocked down the genes and CCK-8 assay measured cell viability in the proliferation biomarkers Ki87 and PCNA. While caspase-8 and caspase-3 activity determined rate of apoptosis. Furthermore, luciferase assay analyzed the luciferase activity and western blotting analysis determined the protein expression of KCNQ1OT1 and let-7a-5p in proliferation and apoptosis biomarkers. Results: The results demonstrated that KCNQ1OT1 is upregulated in OA-mimic cells and promotes the cell viability. KCNQ1OT1 knockdown suppresses cell viability of OA cells. Furthermore KCNQ1OT1 directly binds the 3'-UTR of let-7a-5p to negatively regulate let-7a-5p expression and OA progression. While upregulated let-7a-5p abolishes the proliferation effect of KCNQ1OT1 in OA cells. Conclusion: In summary, our study provides further insights into the underlying molecular mechanisms of KCNQ1OT1 and let-7a-5p suggesting a novel therapeutic approach to OA


2016 ◽  
Author(s):  
Chih-yu Chen ◽  
Wenqiang Shi ◽  
Allison M. Matthews ◽  
Yifeng Li ◽  
David J. Arenillas ◽  
...  

AbstractSex differences in susceptibility and progression have been reported in numerous diseases. Female cells have two copies of the X chromosome with X-chromosome inactivation imparting mono-allelic gene silencing for dosage compensation. However, a subset of genes, named escapees, escape silencing and are transcribed bi-allelically resulting in sexual dimorphism. Here we conducted analyses of the sexes using human datasets to gain perspectives in such regulation. We identified transcription start sites of escapees (escTSSs) based on higher transcription levels in female cells using FANTOM5 CAGE data. Significant over-representations of YY1 transcription factor binding motif and ChIP-seq peaks around escTSSs highlighted its positive association with escapees. Furthermore, YY1 occupancy is significantly biased towards the inactive X (Xi) at long non-coding RNA loci that are frequent contacts of Xi-specific superloops. Our study elucidated the importance of YY1 on transcriptional activity on Xi in general through sequence-specific binding, and its involvement at superloop anchors.


Cancers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 5944
Author(s):  
Jianfei Tang ◽  
Xiaodan Fang ◽  
Juan Chen ◽  
Haixia Zhang ◽  
Zhangui Tang

Oral squamous cell carcinoma (OSCC) is a type of malignancy with high mortality, leading to poor prognosis worldwide. However, the molecular mechanisms underlying OSCC carcinogenesis have not been fully understood. Recently, the discovery and characterization of long non-coding RNAs (lncRNAs) have revealed their regulatory importance in OSCC. Abnormal expression of lncRNAs has been broadly implicated in the initiation and progress of tumors. In this review, we summarize the functions and molecular mechanisms regarding these lncRNAs in OSCC. In addition, we highlight the crosstalk between lncRNA and tumor microenvironment (TME), and discuss the potential applications of lncRNAs as diagnostic and prognostic tools and therapeutic targets in OSCC. Notably, we also discuss lncRNA-targeted therapeutic techniques including CRISPR-Cas9 as well as immune checkpoint therapies to target lncRNA and the PD-1/PD-L1 axis. Therefore, this review presents the future perspectives of lncRNAs in OSCC therapy, but more research is needed to allow the applications of these findings to the clinic.


2018 ◽  
Vol 243 (13) ◽  
pp. 1074-1082 ◽  
Author(s):  
Xiujun Li ◽  
Jiali Wang ◽  
Yuchen Pan ◽  
Yujun Xu ◽  
Dan Liu ◽  
...  

Further studies on the molecular mechanisms of mesenchymal stem cells in the maintenance of growth and function are essential for their clinical application. Growing evidence has shown that long non-coding RNAs (lncRNAs) play an important role in the regulation of mesenchymal stem cells. Recently, it is reported that highly upregulated in liver cancer (HULC), with another lncRNA MALAT-1, accelerated liver cancer stem cell growth. The regulating role of MALAT-1 in mesenchymal stem cells has been investigated. However, the effects of HULC on the mesenchymal stem cells are unknown. In this study, we overexpressed HULC in mesenchymal stem cells derived from umbilical cord and analyzed the cell phenotypes, proliferation, apoptosis, migration, invasion and differentiation of mesenchymal stem cells. We found that overexpression of HULC significantly promotes cell proliferation through promoting cell division and inhibits cell apoptosis. HULC-overexpressed mesenchymal stem cells migrate and invade faster than control mesenchymal stem cells. HULC has no effect on phenotypes and differentiation of mesenchymal stem cells. Furthermore, we found that the expression of HULC in mesenchymal stem cells could be reduced by several inflammatory factors, including TNF-α, TGF-β1, and R848. Taken together, our data demonstrated that HULC has a vital role in the growth and function maintenance of mesenchymal stem cells without affecting differentiation. Impact statement Exploring the molecular mechanisms of growth and function in MSCs is the key to improve their clinical therapeutic effects. Currently, more and more evidence show that the long non-coding RNA (lncRNA) plays an important role in the growth, stemness and function of MSCs.Both HULC and MALAT1 are the earliest discovered LNCRNAs, which are closely related to tumor growth. All of them can promote the growth of liver cancer stem cells. Previously, we have studied the effects of MALAT1 on the growth and function of MSCs. In this study, we focused on the effects of HULC on MSCs. We elucidated the effects of HULC on the growth and differentiation of MSCs, and explored the relationship between inflammatory stimuli and HULC expression in MSCs. Our findings provide a new molecular target for the growth and clinical application of MSCs.


2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Ying Wang ◽  
Chenyi Xue ◽  
Muredach Reilly ◽  
Hanrui Zhang

We aim to interrogate the functions of a subset of human macrophage intergenic long non-coding RNA (lincRNAs) which harbor cardiometabolic trait-associated single nucleotide polymorphisms (SNPs). We have found that one lincRNA RP11-472N13.3 overlaps rs7081678, a SNP significantly associated with central obesity (WHRadjBMI; P =5.57x10 -6 ). RP11-472N13.3 expression is enriched in macrophages relative to other obesity relevant tissues. Thus, RP11-472N13.3 SNPs for obesity may act via its myeloid cell modulation in adipose. In human monocyte-derived macrophage (HMDM), human induced pluripotent stem cell-derived macrophages (IPSDM) and THP1-derived macrophages (THP-1Φ), at RNAseq and Q-PCR, RP11-472N13.3 is abundant in M0 and M2(IL-4) macrophages but markedly suppressed in the M1 state (LPS/IFNγ). RP11-472N13.3 localizes almost exclusively to the cytoplasmic fraction of M0-HMDM. Consistent with GENCODE, our HMDM RNAseq data suggest a single 2-exon isoform. ChIP-seq reveals PU.1 and C/EBP-β binding at RP11-472N13.3 transcription start site. In our HMDM RNAseq (n=30 subjects) data, RP11-472N13.3 expression was inversely correlated with IFNγ-JAK-STAT signaling genes (e.g., IRF4, IL-12A, IL-23, STAT1, SOCS1, SOCS3 ), but not LPS/TLR4 activated genes (e.g., TNFA, CXCL9, CXCL10, IL1B ). Furthermore, KD of RP11-472N13.3 using siRNA or LNA-ASO in THP-1Φ, amplified expression of IFNγ target genes but not LPS/TLR4 targets during M1 activation (LPS/IFNγ). These data suggest its potential role in modulating IFNγ signaling. Mechanistic studies are needed to examine the molecular mechanisms.


2021 ◽  
Vol 27 ◽  
Author(s):  
Bei Wang ◽  
Wen Xu ◽  
Yuxuan Cai ◽  
Kai Liu ◽  
Jiacheng Wu ◽  
...  

Background: Long non-coding RNA (lncRNA) breast cancer anti-estrogen resistance 4 (BCAR4) is a characterized oncogenic lncRNA in different cancers. This review is dedicated to summarize various molecular mechanisms of BCAR4 and demonstrate that the biological functions exerted by BCAR4 are good entry points for therapy. Methods: The molecular mechanism of BCAR4 acting on tumors is summarized by reviewing PubMed. Results: The expression of lncRNA BCAR4 is abnormally increased in all kinds of tumors, including colorectal cancer, prostate cancer, bladder cancer, gastric cancer, chondrosarcoma, glioma, breast cancer, glioma, gastric cancer, liver cancer, cervical cancer, lung cancer, etc. Besides, BCAR4 mediates multiple processes involved in carcinogenesis, including proliferation, invasion, anti-apoptosis, migration. Conclusion: BCAR4 may show great clinical value in this direction as a therapeutic cancer target.


2021 ◽  
Vol 27 ◽  
Author(s):  
Jinlan Chen ◽  
Enqing Meng ◽  
Yexiang Lin ◽  
Yujie Shen ◽  
Chengyu Hu ◽  
...  

Background: As we all know, long non-coding RNA (lncRNA) affects tumor progression, which has caused a great upsurge in recent years. It can also affect the growth, migration, and invasion of tumors. When we refer to the abnormal expression of lncRNA, we will find it associated with malignant tumors. In addition, lncRNA has been proved to be a key targeted gene for the treatment of some diseases. PART1, a member of lncRNA, has been reported as a regulator in the process of tumor occurrence and development. This study aims to reveal the biological functions, specific mechanisms, and clinical significance of PART1 in various tumor cells. Methods: Through the careful search of PUBMED, the mechanisms of the effect of PART1 on tumorigenesis and development are summarized. Results: On the one hand, the up-regulated expression of PART1 plays a tumor-promoting role in tumors, including lung cancer, prostate cancer, bladder cancer and so on. On the other hand, PART1 is down-regulated in gastric cancer, glioma and other tumors to play a tumor inhibitory role. In addition, PART1 regulates tumor growth mainly by targeting microRNA such as miR-635, directly regulating the expression of proteins such as FUS/EZH2, affecting signal pathways such as the Toll-like receptor pathway, or regulating immune cells. Conclusion: PART1 is closely related to tumors by regulating a variety of molecular mechanisms. In addition, PART1 can be used as a clinical marker for the early diagnosis of tumors and plays an important role in tumor-targeted therapy.


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