Cell cycle arrest and gene expression profiling of testis in mice exposed to fluoride

Abstract Introduction: ALK+ anaplastic large cell lymphomas (ALCL) overexpress C/EBPβ, as a consequence of NPM-ALK kinase activity. C/EBPβ is a leucine zipper transcription factor, which plays a major role in cellular differentiation, inflammation, proliferation and metabolism control. To determine the role of C/EBPβ in ALK+ ALCL transformation, and to identify its downstream targets, a highly specific C/EBPβ-shRNA was used to knockdown C/EBPβ. The consequences of C/EBPβ gene-silencing were analyzed by gene expression profiling. Materials and Methods: Four ALK+ ALCL cell lines, SUDHL-1, Kijk, Karpas 299 and SUP-M2 were transfected with lentivirus containing the C/EBPβ shRNA or the vector without shRNA in triplicates. Western Blot analysis and qRT-PCR were performed to quantify the knockdown effect. At day three after infection, RNA was extracted and used for Gene Chip expression analysis (Affymetrix). Using Anova software for statistical analysis, we identified genes, which were regulated in all four cell lines. The effect of C/EBPβ knockdown on proliferation, cell cycle, and viability was analyzed by MTT assay and FACS analysis. Results: In all four ALK+ ALCL, efficient C/EBPβ knockdown resulted in profound growth retardation (up to 84%) compared to control cells after 6 days of infection, and a clear shift from the S phase to the G1 phase in the cell cycle was observed. To identify genes regulated by C/EBPβ in all four cell lines, we performed statistical analysis applying a false discovery rate of 20%, and accepted only genes with a >1,1 and <0,9 fold ratio. We identfied 435 genes regulated after C/EBPβ knockdown (117 upregulated, 318 downregulated). Classification of the differentially expressed genes into biological categories revealed overrepresentation of genes involved in the regulation of kinase activity, cell cycle and proliferation, lymphocyte differentiation, and metabolic processes. In particular, kinases involved in the regulation of JNK activity, which have been shown previously to be involved in proliferation of ALCL, were highly affected by C/EBPβ knockdown. Genomatix Bibliosphere Pathway Analysis revealed C/EBPβ to be connected to pathways involving cell cycle (RUNX3, CCNG1, CDKN2A), apoptosis (FAS, PTPRC, BCL2A1, BIRC3) and MAPK cascades (TRIB1 and several MAP3Ks). Several of the genes identified contain known C/EBPβ binding sites. Conclusions: C/EBPβ silencing induces growth arrest in ALK+ALCL, which correlates with differential expression of genes involved in cell cycle, apoptosis and differentiation. This study reveals C/EBPβ as a master transcription regulator of NPM-ALK induced cellular proliferation, and therefore, an ideal candidate for targeted therapeutic intervention.

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Wogonoside Exerts Anti-Leukemia of AML Cells Via Restricting Phospholipid Scramblase 1 Gene Expression and Promoting Its Translocation Into Nuclear

Blood ◽

10.1182/blood.v118.21.4282.4282 ◽

2011 ◽

Vol 118 (21) ◽

pp. 4282-4282

Author(s):

Yan Chen ◽

Bao-An Chen ◽

Qing-long Guo

Keyword(s):

Gene Expression ◽

Cell Cycle ◽

Cell Cycle Arrest ◽

Cell Lines ◽

Underlying Mechanism ◽

Phase Cell ◽

Western Blots ◽

Phospholipid Scramblase ◽

Cycle Arrest ◽

Phospholipid Scramblase 1

Abstract Abstract 4282 Objective: To evaluate the antileukemic effect of wogonoside and reveal the underlying mechanism. Method: In this study trypan blue dye exclusion assay, MTT assay, and soft agar colony formation assay were used to analysis growth inhibition of wogonoside the on AML (acute human promyelocytic) cell lines. Propidium iodide (PI)-staining and cell cycle-regulatory proteins detecting by western blots were applied to exam whether wogonoside could induce cell cycle arrest. Then a series of experiment were used to assess the ability of wogonoside to overcome the AML associated differentiation block, by using Giemsa staining, Nitroblue tetrazolium (NBT) reduction assay, and cell-surface differentiation antigens expression analysis. Real time PCR, western blots, cycloheximide inhibition test and RNA interference, nuclear and cytoplasmic fractionation, immunofluorescent staining were used to investigate the underlying mechanism. In this point we mainly focus that wogonoside exerts antileukemic by modulating of PLSCR1 gene expression, as well as influence its subcellular localization to play a role in regulating gene transcription. Result: It was demonstrated that wogonoside have the capacity to decrease the growth of myeloid cell lines by induction of G0/1 phase cell cycle arrest and differentiation. This effect is mediated by the increasing in mRNA and up-regulating protein expression of phospholipids scramblase 1 (PLSCR1). Meanwhile wogonoside promoted PLSCR1 traffic into the nucleus, which let PLSCR1 to play a role in regulating cell cycle and differentiation-related genes transcription including p21, p27, c-myc and IP3R1. Conclusion: Wogonoside induced AML cell lines to undergo differentiation and G1 phase arrest by restricting phospholipid scramblase 1 gene expression and promoting its translocation into nuclear. Disclosures: No relevant conflicts of interest to declare.

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The role of HNF4A in GATA4-deficiency phenotypes of hepatocellular carcinoma.

Journal of Clinical Oncology ◽

10.1200/jco.2018.36.4_suppl.284 ◽

2018 ◽

Vol 36 (4_suppl) ◽

pp. 284-284

Author(s):

Yu Bin Tan ◽

Timothy Shuen ◽

Han Chong Toh

Keyword(s):

Gene Expression ◽

Hepatocellular Carcinoma ◽

Cell Cycle ◽

Correlation Analysis ◽

Cell Cycle Arrest ◽

Cell Line ◽

Transgenic Mouse ◽

Cell Lines ◽

Downstream Target ◽

Cycle Arrest

284 Background: Hepatocellular carcinoma (HCC) is the 2nd leading global cause of cancer death. Recently, we have discovered previously undescribed deletion and germline mutation of GATA4 and showed that GATA4 is a key differentiation driver and metabolic regulator in HCC. However, as GATA4 is mostly deleted in HCC, targeting GATA4-downstream molecules is ideal. In this study, proof-of-concept experiments were conducted to show that introduction of HNF4A, which is a GATA4-regulated downstream target, could partially rescue the impaired phenotypes in GATA4-deficient HCC cell line. Methods: Correlation analysis using gene expression microarray of human HCC samples was conducted to identify the genes that are positively correlated with GATA4. A transgenic mouse model with a liver-specific conditional GATA4 knockout was designed to identify liver morphology and gene expression changes which are correlated with the loss of Gata4 in the mouse liver. CRISPR-mediated knockout of GATA4 and lentiviral HNF4A overexpression was carried out in a GATA4-deficient HCC cell lines, PLC/PRF/5 and Hep3B, followed by proliferation, apoptosis, cell cycle and senescence functional assays. Results: Pearson correlation analysis from human HCC samples showed that expression of HNF4A is positively correlated with that of GATA4. Livers from conditional Gata4 knockout mice had lower Hnf4a gene expression when compared to age-matched control mice. Loss of function analysis by CRISPR-mediated GATA4 knockout further showed downregulation of HNF4A in GATA4-deficient PLC/PRF/5 cell line. Lentiviral HNF4A overexpression in PLC/PRF/5 and Hep3B demonstrated reduced proliferation and increased apoptosis while PLC/PRF/5 also showed cell cycle arrest at G2/M phase when compared to control. However, no senescence induction was detected in HNF4A-overexpressing cells. Conclusions: Transgenic mouse data, CRISPR-mediated knockout and analysis of HCC samples showed that HNF4A is a key GATA4-downstream target. HNF4A overexpression decreases proliferation, increases apoptosis and cell cycle arrest in GATA4-deficient HCC cell lines, thus representing a possible therapeutic target for HCC.

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Human Immunodeficiency Virus Type 1 Vpr-Dependent Cell Cycle Arrest through a Mitogen-Activated Protein Kinase Signal Transduction Pathway

Journal of Virology ◽

10.1128/jvi.79.17.11366-11381.2005 ◽

2005 ◽

Vol 79 (17) ◽

pp. 11366-11381 ◽

Cited By ~ 27

Author(s):

Naoto Yoshizuka ◽

Yuko Yoshizuka-Chadani ◽

Vyjayanthi Krishnan ◽

Steven L. Zeichner

Keyword(s):

Gene Expression ◽

Cell Cycle ◽

Human Immunodeficiency Virus ◽

Cell Cycle Arrest ◽

Host Cell ◽

Human Immunodeficiency Virus Type ◽

Erk Pathway ◽

Cycle Arrest ◽

Immunodeficiency Virus

ABSTRACT The human immunodeficiency virus type 1 (HIV-1) Vpr protein has important functions in advancing HIV pathogenesis via several effects on the host cell. Vpr mediates nuclear import of the preintegration complex, induces host cell apoptosis, and inhibits cell cycle progression at G2, which increases HIV gene expression. Some of Vpr's activities have been well described, but some functions, such as cell cycle arrest, are not yet completely characterized, although components of the ATR DNA damage repair pathway and the Cdc25C and Cdc2 cell cycle control mechanisms clearly play important roles. We investigated the mechanisms underlying Vpr-mediated cell cycle arrest by examining global cellular gene expression profiles in cell lines that inducibly express wild-type and mutant Vpr proteins. We found that Vpr expression is associated with the down-regulation of genes in the MEK2-ERK pathway and with decreased phosphorylation of the MEK2 effector protein ERK. Exogenous provision of excess MEK2 reverses the cell cycle arrest associated with Vpr, confirming the involvement of the MEK2-ERK pathway in Vpr-mediated cell cycle arrest. Vpr therefore appears to arrest the cell cycle at G2/M through two different mechanisms, the ATR mechanism and a newly described MEK2 mechanism. This redundancy suggests that Vpr-mediated cell cycle arrest is important for HIV replication and pathogenesis. Our findings additionally reinforce the idea that HIV can optimize the host cell environment for viral replication.

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