scholarly journals Distinct mechanisms control genome recognition by p53 at its target genes linked to different cell fates

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Marina Farkas ◽  
Hideharu Hashimoto ◽  
Yingtao Bi ◽  
Ramana V. Davuluri ◽  
Lois Resnick-Silverman ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Binding ◽  
Cell Cycle Arrest ◽  
Cell Fate ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Binding Modes ◽  
Cell Fate Decisions ◽  
Cycle Arrest

AbstractThe tumor suppressor p53 integrates stress response pathways by selectively engaging one of several potential transcriptomes, thereby triggering cell fate decisions (e.g., cell cycle arrest, apoptosis). Foundational to this process is the binding of tetrameric p53 to 20-bp response elements (REs) in the genome (RRRCWWGYYYN0-13RRRCWWGYYY). In general, REs at cell cycle arrest targets (e.g. p21) are of higher affinity than those at apoptosis targets (e.g., BAX). However, the RE sequence code underlying selectivity remains undeciphered. Here, we identify molecular mechanisms mediating p53 binding to high- and low-affinity REs by showing that key determinants of the code are embedded in the DNA shape. We further demonstrate that differences in minor/major groove widths, encoded by G/C or A/T bp content at positions 3, 8, 13, and 18 in the RE, determine distinct p53 DNA-binding modes by inducing different Arg248 and Lys120 conformations and interactions. The predictive capacity of this code was confirmed in vivo using genome editing at the BAX RE to interconvert the DNA-binding modes, transcription pattern, and cell fate outcome.

scholarly journals The pseudo-caspase FLIP(L) regulates cell fate following p53 activation

2020 ◽  
Vol 117 (30) ◽  
pp. 17808-17819 ◽  
Author(s):  
Andrea Lees ◽  
Alexander J. McIntyre ◽  
Nyree T. Crawford ◽  
Fiammetta Falcone ◽  
Christopher McCann ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Cell Fate ◽  
Target Genes ◽  
Caspase 8 ◽  
Cycle Arrest ◽  
P53 Activation ◽  
Induced Apoptosis

p53 is the most frequently mutated, well-studied tumor-suppressor gene, yet the molecular basis of the switch from p53-induced cell-cycle arrest to apoptosis remains poorly understood. Using a combination of transcriptomics and functional genomics, we unexpectedly identified a nodal role for the caspase-8 paralog and only human pseudo-caspase, FLIP(L), in regulating this switch. Moreover, we identify FLIP(L) as a direct p53 transcriptional target gene that is rapidly up-regulated in response to Nutlin-3A, an MDM2 inhibitor that potently activates p53. Genetically or pharmacologically inhibiting expression of FLIP(L) using siRNA or entinostat (a clinically relevant class-I HDAC inhibitor) efficiently promoted apoptosis in colorectal cancer cells in response to Nutlin-3A, which otherwise predominantly induced cell-cycle arrest. Enhanced apoptosis was also observed when entinostat was combined with clinically relevant, p53-activating chemotherapy in vitro, and this translated into enhanced in vivo efficacy. Mechanistically, FLIP(L) inhibited p53-induced apoptosis by blocking activation of caspase-8 by the TRAIL-R2/DR5 death receptor; notably, this activation was not dependent on receptor engagement by its ligand, TRAIL. In the absence of caspase-8, another of its paralogs, caspase-10 (also transcriptionally up-regulated by p53), induced apoptosis in Nutlin-3A-treated, FLIP(L)-depleted cells, albeit to a lesser extent than in caspase-8-proficient cells. FLIP(L) depletion also modulated transcription of canonical p53 target genes, suppressing p53-induced expression of the cell-cycle regulator p21 and enhancing p53-induced up-regulation of proapoptotic PUMA. Thus, even in the absence of caspase-8/10, FLIP(L) silencing promoted p53-induced apoptosis by enhancing PUMA expression. Thus, we report unexpected, therapeutically relevant roles for FLIP(L) in determining cell fate following p53 activation.

scholarly journals Growth Suppression by Acute PromyelocyticLeukemia-Associated Protein PLZF Is Mediated by Repression ofc-mycExpression

2003 ◽  
Vol 23 (24) ◽  
pp. 9375-9388 ◽  
Author(s):  
Melanie J. McConnell ◽  
Nathalie Chevallier ◽  
Windy Berkofsky-Fessler ◽  
Jena M. Giltnane ◽  
Rupal B. Malani ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Growth ◽  
Cell Cycle Arrest ◽  
Target Genes ◽  
Ectopic Expression ◽  
Growth Suppression ◽  
Quiescent State ◽  
Cycle Arrest

ABSTRACT The transcriptional repressor PLZF was identified by its translocation with retinoic acid receptor alpha in t(11;17) acute promyelocytic leukemia (APL). Ectopic expression of PLZF leads to cell cycle arrest and growth suppression, while disruption of normal PLZF function is implicated in the development of APL. To clarify the function of PLZF in cell growth and survival, we used an inducible PLZF cell line in a microarray analysis to identify the target genes repressed by PLZF. One prominent gene identified was c-myc. The array analysis demonstrated that repression of c-myc by PLZF led to a reduction in c-myc-activated transcripts and an increase in c-myc-repressed transcripts. Regulation of c-myc by PLZF was shown to be both direct and reversible. An interaction between PLZF and the c-myc promoter could be detected both in vitro and in vivo. PLZF repressed the wild-type c-myc promoter in a reporter assay, dependent on the integrity of the binding site identified in vitro. PLZF binding in vivo was coincident with a decrease in RNA polymerase occupation of the c-myc promoter, indicating that repression occurred via a reduction in the initiation of transcription. Finally, expression of c-myc reversed the cell cycle arrest induced by PLZF. These data suggest that PLZF expression maintains a cell in a quiescent state by repressing c-myc expression and preventing cell cycle progression. Loss of this repression through the translocation that occurs in t(11;17) would have serious consequences for cell growth control.

scholarly journals FLIP(L) determines p53 induced life or death

2019 ◽  
Author(s):  
Andrea Lees ◽  
Alexander J. McIntyre ◽  
Fiammetta Falcone ◽  
Nyree T. Crawford ◽  
Christopher McCann ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Cell Fate ◽  
Target Genes ◽  
Hdac Inhibitors ◽  
Caspase 8 ◽  
Cycle Arrest ◽  
P53 Activation ◽  
P53 Target Genes ◽  
Mdm2 Inhibitor

AbstractHow p53 differentially activates cell cycle arrest versus cell death remains poorly understood. Here, we demonstrate that upregulation of canonical pro-apoptotic p53 target genes in colon cancer cells imposes a critical dependence on the long splice form of the caspase-8 regulator FLIP (FLIP(L)), which we identify as a direct p53 transcriptional target. Inhibiting FLIP(L) expression with siRNA or Class-I HDAC inhibitors promotes apoptosis in response to p53 activation by the MDM2 inhibitor Nutlin-3A, which otherwise predominantly induces cell-cycle arrest. When FLIP(L) upregulation is inhibited, apoptosis is induced in response to p53 activation via a novel ligand-independent TRAIL-R2/caspase-8 complex, which, by activating BID, induces mitochondrial-mediated apoptosis. Notably, FLIP(L) depletion inhibits p53-induced expression of the cell cycle regulator p21 and enhances p53-mediated upregulation of PUMA, with the latter activating mitochondrial-mediated apoptosis in FLIP(L)-depleted, Nutlin-3A-treated cells lacking TRAIL-R2/caspase-8. Thus, we report two previously undescribed, novel FLIP(L)-dependent mechanisms that determine cell fate following p53 activation.

scholarly journals GATA-1-Mediated Proliferation Arrest during Erythroid Maturation

2003 ◽  
Vol 23 (14) ◽  
pp. 5031-5042 ◽  
Author(s):  
Marcin Rylski ◽  
John J. Welch ◽  
Ying-Yu Chen ◽  
Danielle L. Letting ◽  
J. Alan Diehl ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Transcription Factor ◽  
Cell Cycle Arrest ◽  
Target Genes ◽  
Cell Cycle Control ◽  
Cyclin Dependent Kinase ◽  
Cycle Arrest ◽  
Hematopoietic Precursor ◽  
Erythroid Maturation

ABSTRACT Transcription factor GATA-1 is essential for erythroid and megakaryocytic maturation. GATA-1 mutations are associated with hematopoietic precursor proliferation and leukemogenesis, suggesting a role in cell cycle control. While numerous GATA-1 target genes specifying mature hematopoietic phenotypes have been identified, how GATA-1 regulates proliferation remains unknown. We used a complementation assay based on synchronous inducible rescue of GATA-1− erythroblasts to show that GATA-1 promotes both erythroid maturation and G1 cell cycle arrest. Molecular studies combined with microarray transcriptome analysis revealed an extensive GATA-1-regulated program of cell cycle control in which numerous growth inhibitors were upregulated and mitogenic genes were repressed. GATA-1 inhibited expression of cyclin-dependent kinase (Cdk) 6 and cyclin D2 and induced the Cdk inhibitors p18 INK4C and p27 Kip1 with associated inactivation of all G1 Cdks. These effects were dependent on GATA-1-mediated repression of the c-myc (Myc) proto-oncogene. GATA-1 inhibited Myc expression within 3 h, and chromatin immunoprecipitation studies indicated that GATA-1 occupies the Myc promoter in vivo, suggesting a direct mechanism for gene repression. Surprisingly, enforced expression of Myc prevented GATA-1-induced cell cycle arrest but had minimal effects on erythroid maturation. Our results illustrate how GATA-1, a lineage-determining transcription factor, coordinates proliferation arrest with cellular maturation through distinct, interrelated genetic programs.

scholarly journals In Vivo and In Vitro Effects of Tracheloside on Colorectal Cancer Cell Proliferation and Metastasis

Antioxidants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 513
Author(s):  
Min-Kyoung Shin ◽  
Yong-Deok Jeon ◽  
Seung-Heon Hong ◽  
Sa-Haeng Kang ◽  
Ji-Ye Kee ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Cancer Progression ◽  
Molecular Mechanisms ◽  
Oxidant Stress ◽  
Mesenchymal Transition ◽  
Cycle Arrest

Recent research suggests a relationship between cancer progression and oxidative mechanisms. Among the phenolic compounds such as tracheloside (TCS) are a major bioactive compound that can combat oxidant stress-related chronic diseases and that also displays anti-tumor activity. Although TCS can inhibit mammalian carcinoma, its effects on colorectal cancer (CRC) have not been clarified. The purpose of this study was to investigate the effects of TCS on the proliferation of CRC cells, the metastasis of CT26 cells, and the molecular mechanisms related to TCS in vitro and in vivo. A cell viability assay showed that TCS inhibited the proliferation of CRC cells. TCS-treated CT26 cells were associated with the upregulation of p16 as well as the downregulation of cyclin D1 and CDK4 in cell cycle arrest. In addition, TCS induced apoptosis of CT26 cells through mitochondria-mediated apoptosis and regulation of the Bcl-2 family. Expression of epithelial–mesenchymal transition (EMT) markers was regulated by TCS treatment in CT26 cells. TCS significantly inhibited the lung metastasis of CT26 cells in a mouse model. These results suggest that TCS, by inducing cell cycle arrest and apoptosis through its anti-oxidant properties, is a novel therapeutic agent that inhibits metastatic phenotypes of murine CRC cells.

scholarly journals Global miRNA Expression Analysis Identifies miR-194, miR-100, miR-125b and miR-199a as Promising Biomarkers for Gastric Cancer and miR-194 Inhibits Gastric Cancer Cell Growth by Targeting CCND1

2020 ◽  
Author(s):  
Dandan Li ◽  
Jingjie Wang ◽  
Meixin Zhang ◽  
Xinhui Hu ◽  
Jiajun She ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Cell Cycle ◽  
Cell Growth ◽  
Cell Cycle Arrest ◽  
Expression Analysis ◽  
Mirna Expression ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Prognostic Biomarkers ◽  
Cycle Arrest

Abstract BackgroundDifferent gastric cancer (GC) subtypes usually possess distinct clinical outcomes. The function of miR-194 in gastric cancer remains unclear and controversial. This study aimed to identify potential microRNAs that differentially expressed in subtypes and to elucidate the molecular mechanisms of miR-194 in GC.MethodsComprehensive miRNA expression analysis was performed using the available miRNA-seq data from TCGA stomach cancer cohort. The preferences of miR-194 in regulating target genes were determined by RNA sequencing studies. The function of miR-194 in GC was explored in GC cell lines by performing qRT-PCR assays, western blot assays, cell proliferation assays, luciferase report assays and flow cytometry assay.ResultsIn this study, we identified a series of miRNAs that can serve as prognostic biomarkers for GC. Among them, miR-100, miR-125b, miR-199a and miR-194 were the 4 most promising prognostic biomarkers in GC due to their significant associations with various clinical characteristics of patients. MiR-100, miR-125b and miR-199a predicted poor prognosis in GC, while miR-194 predicted favorable prognosis in GC. Besides, we provided the first comprehensive transcriptome analysis about miR-194 in GC. The results showed that miR-194 tended to regulated target genes by binding on their 3' untranslated regions in a 7-mer-A1 or 7-mer-m8 or 8-mer manner. The KEGG pathway analysis showed that cell cycle was one of the most affected pathways by miR-194 in GC. Moreover, CCND1 was proved to be a novel target gene of miR-194 in GC. Additionally, the downregulation of CCND1 by miR-194 in GC further led to cell growth inhibition and cell cycle arrest. ConclusionsMiR-100, miR-125b, miR-199a and miR-194 could serve as prognostic and diagnostic biomarkers for GC. MiR-194 might suppress GC cell growth mainly through targeting CCND1 and induction of cell cycle arrest.

scholarly journals A Marine Alkaloid, Ascomylactam A, Suppresses Lung Tumorigenesis via Inducing Cell Cycle G1/S Arrest through ROS/Akt/Rb Pathway

Marine Drugs ◽  
2020 ◽  
Vol 18 (10) ◽  
pp. 494
Author(s):  
Lan Wang ◽  
Yun Huang ◽  
Cui-hong Huang ◽  
Jian-chen Yu ◽  
Ying-chun Zheng ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Molecular Mechanisms ◽  
Soft Agar ◽  
Ros Generation ◽  
Induce Cell Cycle Arrest ◽  
Cycle Arrest

Ascomylactam A was reported for the first time as a new 13-membered-ring macrocyclic alkaloid in 2019 from the mangrove endophytic fungus Didymella sp. CYSK-4 from the South China Sea. The aim of our study was to delineate the effects of ascomylactam A (AsA) on lung cancer cells and explore the antitumor molecular mechanisms underlying of AsA. In vitro, AsA markedly inhibited the cell proliferation with half-maximal inhibitory concentration (IC50) values from 4 to 8 μM on six lung cancer cell lines, respectively. In vivo, AsA suppressed the tumor growth of A549, NCI-H460 and NCI-H1975 xenografts significantly in mice. Furthermore, by analyses of the soft agar colony formation, 5-ethynyl-20-deoxyuridine (EdU) assay, reactive oxygen species (ROS) imaging, flow cytometry and Western blotting, AsA demonstrated the ability to induce cell cycle arrest in G1 and G1/S phases by increasing ROS generation and decreasing of Akt activity. Conversely, ROS inhibitors and overexpression of Akt could decrease cell growth inhibition and cell cycle arrest induced by AsA. Therefore, we believe that AsA blocks the cell cycle via an ROS-dependent Akt/Cyclin D1/Rb signaling pathway, which consequently leads to the observed antitumor effect both in vitro and in vivo. Our results suggest a novel leading compound for antitumor drug development.

Pisosterol Induces G2/M Cell Cycle Arrest and Apoptosis via the ATM/ATR Signaling Pathway in Human Glioma Cells

2020 ◽  
Vol 20 (6) ◽  
pp. 734-750
Author(s):  
Wallax A.S. Ferreira ◽  
Rommel R. Burbano ◽  
Claudia do Ó. Pessoa ◽  
Maria L. Harada ◽  
Bárbara do Nascimento Borges ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Signaling Pathway ◽  
Glioma Cell ◽  
Molecular Mechanisms ◽  
Glioma Cells ◽  
Dependent Manner ◽  
M Cell ◽  
Trypan Blue Exclusion ◽  
Cycle Arrest

Background: Pisosterol, a triterpene derived from Pisolithus tinctorius, exhibits potential antitumor activity in various malignancies. However, the molecular mechanisms that mediate the pisosterol-specific effects on glioma cells remain unknown. Objective: This study aimed to evaluate the antitumoral effects of pisosterol on glioma cell lines. Methods: The 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) and trypan blue exclusion assays were used to evaluate the effect of pisosterol on cell proliferation and viability in glioma cells. The effect of pisosterol on the distribution of the cells in the cell cycle was performed by flow cytometry. The expression and methylation pattern of the promoter region of MYC, ATM, BCL2, BMI1, CASP3, CDK1, CDKN1A, CDKN2A, CDKN2B, CHEK1, MDM2, p14ARF and TP53 was analyzed by RT-qPCR, western blotting and bisulfite sequencing PCR (BSP-PCR). Results: Here, it has been reported that pisosterol markedly induced G2/M arrest and apoptosis and decreased the cell viability and proliferation potential of glioma cells in a dose-dependent manner by increasing the expression of ATM, CASP3, CDK1, CDKN1A, CDKN2A, CDKN2B, CHEK1, p14ARF and TP53 and decreasing the expression of MYC, BCL2, BMI1 and MDM2. Pisosterol also triggered both caspase-independent and caspase-dependent apoptotic pathways by regulating the expression of Bcl-2 and activating caspase-3 and p53. Conclusions: It has been, for the first time, confirmed that the ATM/ATR signaling pathway is a critical mechanism for G2/M arrest in pisosterol-induced glioma cell cycle arrest and suggests that this compound might be a promising anticancer candidate for further investigation.

Trichosanthes dioica seed lectin inhibits Ehrlich ascites carcinoma cells growth in vivo in mice by inducing G 0 /G 1 cell cycle arrest

2021 ◽  
Author(s):  
Shaikh Shohidul Islam ◽  
Md. Rezaul Karim ◽  
A. K. M. Asaduzzaman ◽  
A. H. M. Khurshid Alam ◽  
Zahid Hayat Mahmud ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Ehrlich Ascites Carcinoma ◽  
Carcinoma Cells ◽  
Cycle Arrest ◽  
Ehrlich Ascites ◽  
Trichosanthes Dioica

scholarly journals Selective Inhibition of Aurora Kinase A by AK-01/LY3295668 Attenuates MCC Tumor Growth by Inducing MCC Cell Cycle Arrest and Apoptosis

Cancers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 3708
Author(s):  
Bhaba K. Das ◽  
Aarthi Kannan ◽  
Quy Nguyen ◽  
Jyoti Gogoi ◽  
Haibo Zhao ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Checkpoint Inhibitors ◽  
Treatment Options ◽  
Standard Of Care ◽  
Aurora Kinase ◽  
Selective Inhibition ◽  
Potential Candidate ◽  
Cycle Arrest

Merkel cell carcinoma (MCC) is an often-lethal skin cancer with increasing incidence and limited treatment options. Although immune checkpoint inhibitors (ICI) have become the standard of care in advanced MCC, 50% of all MCC patients are ineligible for ICIs, and amongst those treated, many patients develop resistance. There is no therapeutic alternative for these patients, highlighting the urgent clinical need for alternative therapeutic strategies. Using patient-derived genetic insights and data generated in our lab, we identified aurora kinase as a promising therapeutic target for MCC. In this study, we examined the efficacy of the recently developed and highly selective AURKA inhibitor, AK-01 (LY3295668), in six patient-derived MCC cell lines and two MCC cell-line-derived xenograft mouse models. We found that AK-01 potently suppresses MCC survival through apoptosis and cell cycle arrest, particularly in MCPyV-negative MCC cells without RB expression. Despite the challenge posed by its short in vivo durability upon discontinuation, the swift and substantial tumor suppression with low toxicity makes AK-01 a strong potential candidate for MCC management, particularly in combination with existing regimens.

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