scholarly journals Roles of pRB in the Regulation of Nucleosome and Chromatin Structures

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Chiharu Uchida
Keyword(s):  
Target Genes ◽  
Chromosome Instability ◽  
Cancer Therapies ◽  
Induce Cell Cycle Arrest ◽  
Cellular Events ◽  
Cycle Arrest ◽  
Histone Modifiers ◽  
Physical Interactions ◽  
Functional Inactivation

Retinoblastoma protein (pRB) interacts with E2F and other protein factors to play a pivotal role in regulating the expression of target genes that induce cell cycle arrest, apoptosis, and differentiation. pRB controls the local promoter activity and has the ability to change the structure of nucleosomes and/or chromosomes via histone modification, epigenetic changes, chromatin remodeling, and chromosome organization. Functional inactivation of pRB perturbs these cellular events and causes dysregulated cell growth and chromosome instability, which are hallmarks of cancer cells. The role of pRB in regulation of nucleosome/chromatin structures has been shown to link to tumor suppression. This review focuses on the ability of pRB to control nucleosome/chromatin structures via physical interactions with histone modifiers and chromatin factors and describes cancer therapies based on targeting these protein factors.

Potential of Mesenchymal Stem Cells in Anti-Cancer Therapies

2020 ◽  
Vol 15 (6) ◽  
pp. 482-491 ◽  
Author(s):  
Milena Kostadinova ◽  
Milena Mourdjeva
Keyword(s):  
Cancer Cells ◽  
Small Population ◽  
Tumor Formation ◽  
Bioactive Molecules ◽  
Cancer Therapies ◽  
New Methods ◽  
Cycle Arrest ◽  
Anti Cancer ◽  
Blocking Mechanisms

Mesenchymal stem/stromal cells (MSCs) are localized throughout the adult body as a small population in the stroma of the tissue concerned. In injury, tissue damage, or tumor formation, they are activated and leave their niche to migrate to the site of injury, where they release a plethora of growth factors, cytokines, and other bioactive molecules. With the accumulation of data about the interaction between MSCs and tumor cells, the dualistic role of MSCs remains unclear. However, a large number of studies have demonstrated the natural anti-tumor properties inherent in MSCs, so this is the basis for intensive research for new methods using MSCs as a tool to suppress cancer cell development. This review focuses specifically on advanced approaches in modifying MSCs to become a powerful, precision- targeted tool for killing cancer cells, but not normal healthy cells. Suppression of tumor growth by MSCs can be accomplished by inducing apoptosis or cell cycle arrest, suppressing tumor angiogenesis, or blocking mechanisms mediating metastasis. In addition, the chemosensitivity of cancer cells may be increased so that the dose of the chemotherapeutic agent used could be significantly reduced.

scholarly journals The multiple myeloma–associated MMSET gene contributes to cellular adhesion, clonogenic growth, and tumorigenicity

Blood ◽  
2008 ◽  
Vol 111 (2) ◽  
pp. 856-864 ◽  
Author(s):  
Josh Lauring ◽  
Abde M. Abukhdeir ◽  
Hiroyuki Konishi ◽  
Joseph P. Garay ◽  
John P. Gustin ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Poor Prognosis ◽  
Target Genes ◽  
Hematologic Malignancy ◽  
Growth Factor Receptor ◽  
Cellular Adhesion ◽  
Tumor Formation ◽  
Set Domain ◽  
Cycle Arrest

Multiple myeloma (MM) is an incurable hematologic malignancy characterized by recurrent chromosomal translocations. Patients with t(4;14)(p16;q32) are the worst prognostic subgroup in MM, although the basis for this poor prognosis is unknown. The t(4;14) is unusual in that it involves 2 potential target genes: fibroblast growth factor receptor 3 (FGFR3) and multiple myeloma SET domain (MMSET). MMSET is universally overexpressed in t(4;14) MM, whereas FGFR3 expression is lost in one-third of cases. Nonetheless, the role of MMSET in t(4;14) MM has remained unclear. Here we demonstrate a role for MMSET in t(4;14) MM cells. Down-regulation of MMSET expression in MM cell lines by RNA interference and by selective disruption of the translocated MMSET allele using gene targeting dramatically reduced colony formation in methylcellulose but had only modest effects in liquid culture. In addition, MMSET knockdown led to cell-cycle arrest of adherent MM cells and reduced the ability of MM cells to adhere to extracellular matrix. Finally, MMSET knockdown and knockout reduced tumor formation by MM xenografts. These results provide the first direct evidence that MMSET plays a significant role in t(4;14) MM and suggest that therapies targeting this gene could impact this particular subset of poor-prognosis patients.

scholarly journals Transcriptional Regulation of Genes by Ikaros Tumor Suppressor in Acute Lymphoblastic Leukemia

2020 ◽  
Vol 21 (4) ◽  
pp. 1377
Author(s):  
Pavan Kumar Dhanyamraju ◽  
Soumya Iyer ◽  
Gayle Smink ◽  
Yevgeniya Bamme ◽  
Preeti Bhadauria ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
Tumor Suppressor ◽  
Chromatin Remodeling ◽  
Target Genes ◽  
Cellular Proliferation ◽  
Lymphoblastic Leukemia ◽  
Regulatory Elements ◽  
Binding Motif ◽  
Functional Inactivation

Regulation of oncogenic gene expression by transcription factors that function as tumor suppressors is one of the major mechanisms that regulate leukemogenesis. Understanding this complex process is essential for explaining the pathogenesis of leukemia as well as developing targeted therapies. Here, we provide an overview of the role of Ikaros tumor suppressor and its role in regulation of gene transcription in acute leukemia. Ikaros (IKZF1) is a DNA-binding protein that functions as a master regulator of hematopoiesis and the immune system, as well as a tumor suppressor in acute lymphoblastic leukemia (ALL). Genetic alteration or functional inactivation of Ikaros results in the development of high-risk leukemia. Ikaros binds to the specific consensus binding motif at upstream regulatory elements of its target genes, recruits chromatin-remodeling complexes and activates or represses transcription via chromatin remodeling. Over the last twenty years, a large number of Ikaros target genes have been identified, and the role of Ikaros in the regulation of their expression provided insight into the mechanisms of Ikaros tumor suppressor function in leukemia. Here we summarize the role of Ikaros in the regulation of the expression of the genes whose function is critical for cellular proliferation, development, and progression of acute lymphoblastic leukemia.

scholarly journals MicroRNAs in the DNA Damage/Repair Network and Cancer

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Alessandra Tessitore ◽  
Germana Cicciarelli ◽  
Filippo Del Vecchio ◽  
Agata Gaggiano ◽  
Daniela Verzella ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Dna Damage Repair ◽  
Transcriptional Level ◽  
Cancer Therapies ◽  
Induce Cell Cycle Arrest ◽  
Cycle Arrest ◽  
Damage Repair ◽  
Response Network ◽  
Multistep Process

Cancer is a multistep process characterized by various and different genetic lesions which cause the transformation of normal cells into tumor cells. To preserve the genomic integrity, eukaryotic cells need a complex DNA damage/repair response network of signaling pathways, involving many proteins, able to induce cell cycle arrest, apoptosis, or DNA repair. Chemotherapy and/or radiation therapy are the most commonly used therapeutic approaches to manage cancer and act mainly through the induction of DNA damage. Impairment in the DNA repair proteins, which physiologically protect cells from persistent DNA injury, can affect the efficacy of cancer therapies. Recently, increasing evidence has suggested that microRNAs take actively part in the regulation of the DNA damage/repair network. MicroRNAs are endogenous short noncoding molecules able to regulate gene expression at the post-transcriptional level. Due to their activity, microRNAs play a role in many fundamental physiological and pathological processes. In this review we report and discuss the role of microRNAs in the DNA damage/repair and cancer.

Role Of Histone Deacetylase 6 (HDAC6) In The Modulation Of STAT Pathways and Immune Function Of APCs

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1032-1032
Author(s):  
Maritza Lienlaf ◽  
Patricio Perez-Villarroel ◽  
Fengdong Cheng ◽  
Calvin K. Lee ◽  
Jorge Canales ◽  
...  
Keyword(s):  
Cell Lines ◽  
Histone Deacetylases ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Conflicts Of Interest ◽  
Cell Cycle Control ◽  
Critical Role ◽  
Histone Deacetylase 6 ◽  
Histone Modifiers

Abstract Histone deacetylases (HDACs), originally discovered as histone modifiers are now proposed as important regulators of non-chromatin related processes, including the regulation of cellular pathways involved in the production of anti- and pro-inflammatory cytokines and the subsequent function of antigen-presenting cells (APCs). We have recently identified HDAC6 as a positive regulatory factor in the production of IL-10. However, the participation of this HDAC in other immune related cellular processes remains unknown. In this work we present evidence of the important role of HDAC6 in the modulation of the JAK/STAT pathway through the IL-6 regulation. We generated knockdown cell lines of HDAC6 (HDAC6KD) and non-target (NT) cells as a control in RAW264.7 murine macrophages using lentiviral shRNA. Two HADC6KD and two NT cell lines were treated with LPS or were left untreated and then analyzed by microarray. In HDAC6KD cells we found 1542 genes were down-regulated and 775 up-regulated in HDAC6KD cells. Their ontology distribution revealed significant changes in immune-related and apoptosis/cell cycle control genes. Importantly, we observed that most STAT3 and SP1 target genes were down regulated in HDAC6KD cells, suggesting the participation of HDAC6 in the regulation of these two transcription factors. Further analysis evidenced that the phosphorylation of STAT3 and the acetylation of Sp1 were diminished in HDAC6KD cells when compared against control cells. Chromatin immuneprecipitacion (CHIP) assays indicate that this particular effect of abrogation of HDAC6 involved histone modifications at the IL-6 promoter level, and more importantly, the recruitment of STAT3 and Sp1 to the IL-6 promoter was abrogated. Then, we analyzed the relevance of these findings by studying the tolerogenic JAK/STAT signaling pathway, which is known to be activated by IL-6 and critical in the final outcome of APCs in response to stimuli. Our observations included a complete abrogation in the phosphorylation of JAK2 and STAT3 proteins in HDAC6KD cells in response to LPS, which was reverted when these cells were treated with exogenous IL-6. Our final results demonstrate a critical role of HDAC6 in the modulation of IL-6 and the potential role of HDAC6 in the regulation of the JAK/STAT3 pathway. In addition HDAC6 is a regulator of SP1 and STAT3 target genes. These findings provide insight into the molecular mechanisms controlling the immunogenicity of APCs, supporting the use of HDAC6 inhibitors to enhance immune activation, and positioning HDAC6 as a potential therapeutic target. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Berberine Suppresses Stemness and Tumorigenicity of Colorectal Cancer Stem-Like Cells by Inhibiting m6A Methylation

2021 ◽  
Vol 11 ◽  
Author(s):  
Ziyi Zhao ◽  
Jinhao Zeng ◽  
Qiang Guo ◽  
Kunming Pu ◽  
Yi Yang ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Isoquinoline Alkaloid ◽  
Negative Regulator ◽  
Cancer Therapies ◽  
Antitumor Activities ◽  
Chemotherapy Agent ◽  
Cycle Arrest ◽  
After Cancer ◽  
Induced Apoptosis

BackgroundCancer stem cells (CSCs) are able to survive after cancer therapies, resulting in tumor progression and recurrence, as is seen in colorectal cancer. Therapies targeting CSCs are regarded as novel and promising strategies for efficiently eradicating tumors. Berberine, an isoquinoline alkaloid extracted from the Chinese herbal medicine Coptis chinensis, was found to have antitumor activities against colorectal cancer, without knowing whether it exerts inhibitory effects on colorectal CSCs and the potential mechanisms.MethodsIn this study, we examined the inhibitory roles of Berberine on CSCs derived from HCT116 and HT29 by culturing in serum-free medium. We also examined the effects of Berberine on m6A methylation via regulating fat mass and obesity-associated protein (FTO), by downregulating β-catenin.ResultsWe examined the effects of Berberine on the tumorigenicity, growth, and stemness of colorectal cancer stem-like cells. The regulatory effect of Berberine on N6-methyladenosine (m6A), an abundant mRNA modification, was also examined. Berberine treatment decreased cell proliferation by decreasing cyclin D1 and increasing p27 and p21 and subsequently induced cell cycle arrest at the G1/G0 phase. Berberine treatment also decreased colony formation and induced apoptosis. Berberine treatment transcriptionally increased FTO and thus decreased m6A methylation, which was reversed by both FTO knockdown and the addition of the FTO inhibitor FB23-2. Berberine induced FTO-related decreases in stemness in HCT116 and HT29 CSCs. Berberine treatment also increased chemosensitivity in CSCs and promoted chemotherapy agent-induced apoptosis. Moreover, we also found that Berberine treatment increased FTO by decreasing β-catenin, which is a negative regulator of FTO.ConclusionsOur observation that Berberine effectively decreased m6A methylation by decreasing β-catenin and subsequently increased FTO suggests a role of Berberine in modulating stemness and malignant behaviors in colorectal CSCs.

miR-34a contributes to megakaryocytic differentiation of K562 cells independently of p53

Blood ◽  
2009 ◽  
Vol 114 (10) ◽  
pp. 2181-2192 ◽  
Author(s):  
Francisco Navarro ◽  
David Gutman ◽  
Eti Meire ◽  
Mario Cáceres ◽  
Isidore Rigoutsos ◽  
...  
Keyword(s):  
Phorbol Ester ◽  
Target Genes ◽  
Phorbol Esters ◽  
K562 Cells ◽  
Suppressor Gene ◽  
Human Leukemia ◽  
Cycle Arrest ◽  
Human Leukemia Cells ◽  
Megakaryocyte Differentiation

Abstract The role of miRNAs in regulating megakaryocyte differentiation was examined using bipotent K562 human leukemia cells. miR-34a is strongly up-regulated during phorbol ester–induced megakaryocyte differentiation, but not during hemin-induced erythrocyte differentiation. Enforced expression of miR-34a in K562 cells inhibits cell proliferation, induces cell-cycle arrest in G1 phase, and promotes megakaryocyte differentiation as measured by CD41 induction. miR-34a expression is also up-regulated during thrombopoietin-induced differentiation of CD34+ hematopoietic precursors, and its enforced expression in these cells significantly increases the number of megakaryocyte colonies. miR-34a directly regulates expression of MYB, facilitating megakaryocyte differentiation, and of CDK4 and CDK6, to inhibit the G1/S transition. However, these miR-34a target genes are down-regulated rapidly after inducing megakaryocyte differentiation before miR-34a is induced. This suggests that miR-34a is not responsible for the initial down-regulation but may contribute to maintaining their suppression later on. Previous studies have implicated miR-34a as a tumor suppressor gene whose transcription is activated by p53. However, in p53-null K562 cells, phorbol esters induce miR-34a expression independently of p53 by activating an alternative phorbol ester-responsive promoter to produce a longer pri-miR-34a transcript.

scholarly journals p53 Mediates Colistin-Induced Autophagy and Apoptosis in PC-12 Cells

2016 ◽  
Vol 60 (9) ◽  
pp. 5294-5301 ◽  
Author(s):  
Ling Zhang ◽  
Daoyuan Xie ◽  
Xueping Chen ◽  
Maria L. R. Hughes ◽  
Guozheng Jiang ◽  
...  
Keyword(s):  
Target Genes ◽  
Mammalian Target Of Rapamycin ◽  
Inhibitory Effect ◽  
Pc 12 Cells ◽  
Link Type ◽  
Cellular Events ◽  
Cycle Arrest ◽  
Induced Apoptosis ◽  
20 Nm ◽  
Amp Activated Protein Kinase

ABSTRACTThe mechanism of colistin-induced neurotoxicity is still unknown. Our recent study (L. Zhang, Y. H. Zhao, W. J. Ding, G. Z. Jiang, Z. Y. Lu, L. Li, J. L. Wang, J. Li, and J. C. Li, Antimicrob Agents Chemother 59:2189–2197, 2015,http://dx.doi.org/10.1128/AAC.04092-14; H. Jiang, J. C. Li, T. Zhou, C. H. Wang, H. Zhang, and H. Wang, Int J Mol Med 33:1298–1304, 2014,http://dx.doi.org/10.3892/ijmm.2014.1684) indicates that colistin induces autophagy and apoptosis in rat adrenal medulla PC-12 cells, and there is interplay between both cellular events. As an important cellular stress sensor, phosphoprotein p53 can trigger cell cycle arrest and apoptosis and regulate autophagy. The aim of the present study was to investigate the involvement of the p53 pathway in colistin-induced neurotoxicity in PC-12 cells. Specifically, cells were treated with colistin (125 μg/ml) in the absence and presence of a p53 inhibitor, pifithrin-α (PFT-α; 20 nM), for 12 h and 24 h, and the typical hallmarks of autophagy and apoptosis were examined by fluorescence/immunofluorescence microscopy and electron microscopy, real-time PCR, and Western blotting. The results indicate that colistin had a stimulatory effect on the expression levels of the target genes and proteins involved in autophagy and apoptosis, including LC3-II/I, p53, DRAM (damage-regulated autophagy modulator), PUMA (p53 upregulated modulator of apoptosis), Bax, p-AMPK (activated form of AMP-activated protein kinase), and caspase-3. In contrast, colistin appeared to have an inhibitory effect on the expression of p-mTOR (activated form of mammalian target of rapamycin), which is another target protein in autophagy. Importantly, analysis of the levels of p53 in the cells treated with colistin revealed an increase in nuclear p53 at 12 h and cytoplasmic p53 at 24 h. Pretreatment of colistin-treated cells with PFT-α inhibited autophagy and promoted colistin-induced apoptosis. This is the first study to demonstrate that colistin-induced autophagy and apoptosis are associated with the p53-mediated pathway.

scholarly journals Human Herpesvirus 6A (HHV-6A) and HHV-6B Alter E2F1/Rb Pathways and E2F1 Localization and Cause Cell Cycle Arrest in Infected T Cells

2007 ◽  
Vol 81 (24) ◽  
pp. 13499-13508 ◽  
Author(s):  
Guy Mlechkovich ◽  
Niza Frenkel
Keyword(s):  
Cell Cycle ◽  
T Cells ◽  
Cell Cycle Arrest ◽  
Cellular Localization ◽  
Target Genes ◽  
Viral Infections ◽  
Human Herpesvirus ◽  
Cycle Arrest ◽  
E2f Transcription Factors

ABSTRACT E2F transcription factors play pivotal roles in controlling the expression of genes involved in cell viability as well as genes involved in cell death. E2F1 is an important constituent of this protein family, which thus far contains eight members. The interaction of E2F1 with its major regulator, retinoblastoma protein (Rb), has been studied extensively in the past two decades, concentrating on the role of E2F1 in transcriptional regulation and the role of Rb in cell replication and cancer formation. Additionally, the effect of viral infections on E2F1/Rb interactions has been analyzed for different viruses, concentrating on cell division, which is essential for viral replication. In the present study, we monitored E2F1-Rb interactions during human herpesvirus 6A (HHV-6A) and HHV-6B infections of SupT1 T cells. The results have shown the following dramatic alterations in E2F1-Rb pathways compared to the pathways of parallel mock-infected control cultures. (i) The E2F1 levels were elevated during viral infections. (ii) The cellular localization of E2F1 was dramatically altered, and it was found to accumulate both in the cytoplasmic and nuclear fractions, as opposed to the strict nuclear localization seen in the mock-infected cells. (iii) Although E2F1 expression was elevated, two exemplary target genes, cyclin E and MCM5, were not upregulated. (iv) The Rb protein was dephosphorylated early postinfection, a trait that also occurred with UV-inactivated virus. (v) Infection was associated with significant reduction of E2F1/Rb complexing. (vi) HHV-6 infections were accompanied by cell cycle arrest. The altered E2F1-Rb interactions and functions might contribute to the observed cell cycle arrest.

scholarly journals NEK1 Phosphorylation of YAP Promotes Its Stabilization and Transcriptional Output

Cancers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3666
Author(s):  
Md Imtiaz Khalil ◽  
Ishita Ghosh ◽  
Vibha Singh ◽  
Jing Chen ◽  
Haining Zhu ◽  
...  
Keyword(s):  
Cancer Progression ◽  
Target Genes ◽  
Progressive Failure ◽  
Lncap Cells ◽  
Cycle Arrest ◽  
Castration Resistant ◽  
Damage Response ◽  
Transcriptional Output

Most prostate cancer (PCa) deaths result from progressive failure in standard androgen deprivation therapy (ADT), leading to metastatic castration-resistant PCa (mCRPC); however, the mechanism and key players leading to this are not fully understood. While studying the role of tousled-like kinase 1 (TLK1) and never in mitosis gene A (NIMA)-related kinase 1 (NEK1) in a DNA damage response (DDR)-mediated cell cycle arrest in LNCaP cells treated with bicalutamide, we uncovered that overexpression of wt-NEK1 resulted in a rapid conversion to androgen-independent (AI) growth, analogous to what has been observed when YAP1 is overexpressed. We now report that overexpression of wt-NEK1 results in accumulation of YAP1, suggesting the existence of a TLK1>NEK1>YAP1 axis that leads to adaptation to AI growth. Further, YAP1 is co-immunoprecipitated with NEK1. Importantly, NEK1 was able to phosphorylate YAP1 on six residues in vitro, which we believe are important for stabilization of the protein, possibly by increasing its interaction with transcriptional partners. In fact, knockout (KO) of NEK1 in NT1 PCa cells resulted in a parallel decrease of YAP1 level and reduced expression of typical YAP-regulated target genes. In terms of cancer potential implications, the expression of NEK1 and YAP1 proteins was found to be increased and correlated in several cancers. These include PCa stages according to Gleason score, head and neck squamous cell carcinoma, and glioblastoma, suggesting that this co-regulation is imparted by increased YAP1 stability when NEK1 is overexpressed or activated by TLK1, and not through transcriptional co-expression. We propose that the TLK1>NEK1>YAP1 axis is a key determinant for cancer progression, particularly during the process of androgen-sensitive to -independent conversion during progression to mCRPC.

Sign in / Sign up

Export Citation Format

Share Document