scholarly journals The inflammatory kinase IKKα phosphorylates and stabilizes c-Myc and enhances its activity

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Bernhard Moser ◽  
Bernhard Hochreiter ◽  
José Basílio ◽  
Viola Gleitsmann ◽  
Anja Panhuber ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Transcriptional Activity ◽  
Significant Positive Correlation ◽  
Optical Pulse ◽  
Gene Knockout ◽  
Iκb Kinase ◽  
Mouse Prostate ◽  
Ikk Complex ◽  
Chemical Inhibition ◽  
Prostate Epithelium

Abstract Background The IκB kinase (IKK) complex, comprising the two enzymes IKKα and IKKβ, is the main activator of the inflammatory transcription factor NF-κB, which is constitutively active in many cancers. While several connections between NF-κB signaling and the oncogene c-Myc have been shown, functional links between the signaling molecules are still poorly studied. Methods Molecular interactions were shown by co-immunoprecipitation and FRET microscopy. Phosphorylation of c-Myc was shown by kinases assays and its activity by improved reporter gene systems. CRISPR/Cas9-mediated gene knockout and chemical inhibition were used to block IKK activity. The turnover of c-Myc variants was determined by degradation in presence of cycloheximide and by optical pulse-chase experiments.. Immunofluorescence of mouse prostate tissue and bioinformatics of human datasets were applied to correlate IKKα- and c-Myc levels. Cell proliferation was assessed by EdU incorporation and apoptosis by flow cytometry. Results We show that IKKα and IKKβ bind to c-Myc and phosphorylate it at serines 67/71 within a sequence that is highly conserved. Knockout of IKKα decreased c-Myc-activity and increased its T58-phosphorylation, the target site for GSK3β, triggering polyubiquitination and degradation. c-Myc-mutants mimicking IKK-mediated S67/S71-phosphorylation exhibited slower turnover, higher cell proliferation and lower apoptosis, while the opposite was observed for non-phosphorylatable A67/A71-mutants. A significant positive correlation of c-Myc and IKKα levels was noticed in the prostate epithelium of mice and in a variety of human cancers. Conclusions Our data imply that IKKα phosphorylates c-Myc on serines-67/71, thereby stabilizing it, leading to increased transcriptional activity, higher proliferation and decreased apoptosis.

scholarly journals MP70-13 DEPLETION OF PMEPA1 GENE CONFERS INCREASED CELL PROLIFERATION IN MOUSE PROSTATE EPITHELIUM

2018 ◽  
Vol 199 (4S) ◽  
Author(s):  
Hua Li ◽  
Shashwat Sharad ◽  
Talai Barbiev ◽  
Wei Huang ◽  
Yingjie Song ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Mouse Prostate ◽  
Prostate Epithelium

scholarly journals Annexin-A1 SUMOylation regulates microglial polarization after cerebral ischemia by modulating IKKα stability via selective autophagy

2021 ◽  
Vol 7 (4) ◽  
pp. eabc5539
Author(s):  
Xing Li ◽  
Qian Xia ◽  
Meng Mao ◽  
Huijuan Zhou ◽  
Lu Zheng ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Underlying Mechanism ◽  
Nuclear Factor Κb ◽  
Annexin A1 ◽  
Selective Autophagy ◽  
Microglial Polarization ◽  
Proinflammatory Mediators ◽  
Therapeutic Benefits ◽  
Iκb Kinase ◽  
Ikk Complex

Annexin-A1 (ANXA1) has recently been proposed to play a role in microglial activation after brain ischemia, but the underlying mechanism remains poorly understood. Here, we demonstrated that ANXA1 is modified by SUMOylation, and SUMOylated ANXA1 could promote the beneficial phenotype polarization of microglia. Mechanistically, SUMOylated ANXA1 suppressed nuclear factor κB activation and the production of proinflammatory mediators. Further study revealed that SUMOylated ANXA1 targeted the IκB kinase (IKK) complex and selectively enhanced IKKα degradation. Simultaneously, we detected that SUMOylated ANXA1 facilitated the interaction between IKKα and NBR1 to promote IKKα degradation through selective autophagy. Further work revealed that the overexpression of SUMOylated ANXA1 in microglia/macrophages resulted in marked improvement in neurological function in a mouse model of cerebral ischemia. Collectively, our study demonstrates a previously unidentified mechanism whereby SUMOylated ANXA1 regulates microglial polarization and strongly indicates that up-regulation of ANXA1 SUMOylation in microglia may provide therapeutic benefits for cerebral ischemia.

scholarly journals Oxidative Stress Transiently Decreases the IKK Complex (IKKα, β, and γ), an Upstream Component of NF-κB Signaling, after Transient Focal Cerebral Ischemia in Mice

2005 ◽  
Vol 25 (10) ◽  
pp. 1301-1311 ◽  
Author(s):  
Yun S Song ◽  
Yong-Sun Lee ◽  
Pak H Chan
Keyword(s):  
Cerebral Ischemia ◽  
Focal Cerebral Ischemia ◽  
Nuclear Factor Κb ◽  
Nuclear Factor ◽  
Dna Array ◽  
Wild Type ◽  
Iκb Kinase ◽  
Transient Focal Cerebral Ischemia ◽  
Ikk Complex ◽  
In The Wild

Nuclear factor-κB (NF-κB) has a central role in coordinating the expression of a wide variety of genes that control cerebral ischemia. Although there has been intense research on NF-κB, its mechanisms in the ischemic brain have not been clearly elucidated. We investigated the temporal profile of NF-κB-related genes using a complementary DNA array method in wild-type mice and human copper/zinc-superoxide dismutase transgenic (SOD1 Tg) mice that had low-level reactive oxygen species (ROS) by scavenging superoxide. Our DNA array showed that IκB kinase (IKK) complex (IKKα, β, and γ) mRNA in the wild-type mice was decreased as early as 1 h after reperfusion, after 30 mins of transient focal cerebral ischemia (tFCI). In contrast, tFCI in the SOD1 Tg mice caused an increase in the IKK complex. The IKK complex protein levels were also drastically decreased at 1 h in the wild-type mice, but did not change in the SOD1 Tg mice throughout the 7 days. Electrophoretic mobility shift assay revealed activation of NF-κB DNA binding after tFCI in the wild-type mice. Nuclear factor-κB activation occurred at the same time, as did the phosphorylation and degradation of the inhibitory protein κBα. However, SOD1 prevented NF-κB activation, and phosphorylation and degradation of IκBα after tFCI. Superoxide production and ubiquitinated protein in the SOD1 Tg mice were also lower than in the wild-type mice after tFCI. These results suggest that ROS are implicated in transient downregulation of IKKα, β, and γ in cerebral ischemia.

scholarly journals Expression of 58-kD Microspherule Protein (MSP58) is Highly Correlated with PET Imaging of Tumor Malignancy and Cell Proliferation in Glioma Patients

2016 ◽  
Vol 38 (2) ◽  
pp. 635-645 ◽  
Author(s):  
Wei Lin ◽  
Shu-hui Dai ◽  
Tao Chen ◽  
Nobuyuki Kawai ◽  
Keisuke Miyake ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Significant Positive Correlation ◽  
Tumor Grade ◽  
Molecular Therapy ◽  
Ki 67 ◽  
Positive Correlation ◽  
Flt Pet ◽  
Pet Tracer ◽  
Positron Emission ◽  
Regulation Functions

Background/Aims: The nucleolar 58-kDa microspherule protein (MSP58) has important transcriptional regulation functions and plays a crucial role in the tumorigenesis and progression of cancers. 3'-deoxy-3'-[18F]fluorothymidine (FLT) has emerged as a promising positron emission tomography (PET) tracer for evaluating tumor malignancy and cell proliferation. Methods: In the present study, the expression of MSP58 was evaluated by immunohistochemistry and the corresponding PET image was examined using FLT-PET in 55 patients with various grades of gliomas. Results: The immunoreactivity score (IRS) of MSP58 increased with tumor grade with grade IV gliomas exhibiting the highest expression and showed a highly significant positive correlation with the Ki-67 index (r = 0.65, P < 0.001). The IRS of MSP58 in the tumor showed a highly significant positive correlation with corresponding FLT uptake value (r = 0.61, P < 0.001). The correlation between MSP58 expression and glioma malignancy was also confirmed by immunofluorescence, RT-PCR and western blot analysis. FLT uptake value also exhibited a highly significant positive correlation with the Ki-67 index (r = 0.59, P < 0.001). Kaplan-Meier analysis revealed that MSP58 expression has a significant prognostic ability for the overall survival time similar to that found in the uptake value of FLT-PET. Conclusion: These results indicate that MSP58 plays an important role in cell proliferation and will be one of the potential candidates of molecular therapy targeting proliferation. FLT-PET might be used as an early measure of treatment response in the proliferation-targeted therapy.

scholarly journals Human Endogenous Retrovirus (HERV)-K env Gene Knockout Affects Tumorigenic Characteristics of nupr1 Gene in DLD-1 Colorectal Cancer Cells

2021 ◽  
Vol 22 (8) ◽  
pp. 3941
Author(s):  
Eun-Ji Ko ◽  
Mee-Sun Ock ◽  
Yung-Hyun Choi ◽  
Juan L. Iovanna ◽  
Seyoung Mun ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Proliferation ◽  
Cancer Cells ◽  
Gene Knockout ◽  
Endogenous Retroviruses ◽  
Human Endogenous Retrovirus ◽  
Ros Generation ◽  
Nude Mouse Model ◽  
Env Protein

Human endogenous retroviruses (HERVs) are suggested to be involved in the development of certain diseases, especially cancers. To elucidate the function of HERV-K Env protein in cancers, an HERV-K env gene knockout (KO) in DLD-1 colorectal cancer cell lines was generated using the CRISPR-Cas9 system. Transcriptome analysis of HERV-K env KO cells using next-generation sequencing (NGS) was performed to identify the key genes associated with the function of HERV-K Env protein. The proliferation of HERV-K env KO cells was significantly reduced in in vitro culture as well as in in vivo nude mouse model. Tumorigenic characteristics, including migration, invasion, and tumor colonization, were also significantly reduced in HERV-K env KO cells. Whereas, they were enhanced in HERV-K env over-expressing DLD-1 cells. The expression of nuclear protein-1 (NUPR1), an ER-stress response factor that plays an important role in cell proliferation, migration, and reactive oxygen species (ROS) generation in cancer cells, significantly reduced in HERV-K env KO cells. ROS levels and ROS-related gene expression was also significantly reduced in HERV-K env KO cells. Cells transfected with NUPR1 siRNA (small interfering RNA) exhibited the same phenotype as HERV-K env KO cells. These results suggest that the HERV-K env gene affects tumorigenic characteristics, including cell proliferation, migration, and tumor colonization through NUPR1 related pathway.

scholarly journals Endothelial NO Synthase-Dependent S-Nitrosylation of β-Catenin Prevents Its Association with TCF4 and Inhibits Proliferation of Endothelial Cells Stimulated by Wnt3a

2017 ◽  
Vol 37 (12) ◽  
Author(s):  
Ying Zhang ◽  
Rony Chidiac ◽  
Chantal Delisle ◽  
Jean-Philippe Gratton
Keyword(s):  
Cell Proliferation ◽  
Endothelial Cells ◽  
Endothelial Cell ◽  
Transcriptional Activity ◽  
No Synthase ◽  
Endothelial Cell Proliferation ◽  
Dependent Manner ◽  
Endothelial No Synthase ◽  
Binding Interface ◽  
Critical Residue

ABSTRACT Nitric oxide (NO) produced by endothelial NO synthase (eNOS) modulates many functions in endothelial cells. S-nitrosylation (SNO) of cysteine residues on β-catenin by eNOS-derived NO has been shown to influence intercellular contacts between endothelial cells. However, the implication of SNO in the regulation of β-catenin transcriptional activity is ill defined. Here, we report that NO inhibits the transcriptional activity of β-catenin and endothelial cell proliferation induced by activation of Wnt/β-catenin signaling. Interestingly, induction by Wnt3a of β-catenin target genes, such as the axin2 gene, is repressed in an eNOS-dependent manner by vascular endothelial growth factor (VEGF). We identified Cys466 of β-catenin as a target for SNO by eNOS-derived NO and as the critical residue for the repressive effects of NO on β-catenin transcriptional activity. Furthermore, we observed that Cys466 of β-catenin, located at the binding interface of the β-catenin–TCF4 transcriptional complex, is essential for disruption of this complex by NO. Importantly, Cys466 of β-catenin is necessary for the inhibitory effects of NO on Wnt3a-stimulated proliferation of endothelial cells. Thus, our data define the mechanism responsible for the repressive effects of NO on the transcriptional activity of β-catenin and link eNOS-derived NO to the modulation by VEGF of Wnt/β-catenin-induced endothelial cell proliferation.

scholarly journals Methylation of transcription factor YY2 regulates its transcriptional activity and cell proliferation

2017 ◽  
Vol 3 (1) ◽  
Author(s):  
Xiao-nan Wu ◽  
Tao-tao Shi ◽  
Yao-hui He ◽  
Fei-fei Wang ◽  
Rui Sang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Transcription Factor ◽  
Transcriptional Activity

Abstract 633: Protein Kinase D Regulates VEGFR-2 Transcriptional Activity in Endothelial Cells Through AP-2β

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Luke H Hoeppner ◽  
Resham Bhattacharya ◽  
Ying Wang ◽  
Ramcharan Singh Angom ◽  
Enfeng Wang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Endothelial Cells ◽  
Heart Disease ◽  
Binding Sites ◽  
Transcriptional Activity ◽  
Endothelial Cell Proliferation ◽  
Protein Kinase D ◽  
Cell Proliferation And Migration ◽  
And Migration ◽  
Proliferation And Migration

Vascular endothelial growth factor A (VEGF) signals primarily through its cognate receptor VEGFR-2 to control vasculogenesis and angiogenesis. Dysregulation of these physiological processes contributes to the pathologies of heart disease, stroke, and cancer. Protein kinase D (PKD) plays a crucial role in the regulation of angiogenesis by modulating endothelial cell proliferation and migration. In human umbilical vein endothelial cells (HUVEC) and human blood outgrowth endothelial cells (BOEC), knockdown of PKD-1 or PKD-2 downregulates VEGFR-2 and significantly inhibits VEGF-induced endothelial cell proliferation and migration. We sought to determine the molecular mechanism through which PKD modulates VEGFR-2 expression. Based on bioinformatics data, activating enhancer binding protein 2 (AP2) binding sites exist within the VEGFR-2 promoter. Thus, we hypothesized PKD may downregulate VEGFR-2 through AP2-mediated transcriptional repression of the VEGFR-2 promoter. Indeed, AP2β binds the VEGFR-2 promoter upon PKD knockdown in HUVEC as evident by chromatin immunoprecipitation assay. Luciferase reporter assays using serial deletions of AP2β binding sites within the VEGFR-2 promoter revealed transcriptional activity negatively correlated with the number of AP2β binding sites, thus confirming negative regulation of VEGFR-2 transcription by AP2β. Next, using siRNA, we demonstrated that upregulation of AP2β decreased VEGFR-2 expression and loss of AP2β enhanced VEGFR-2 expression. In vivo studies confirmed this finding as we observed increased VEGFR-2 immunostaining in the dorsal horn of the spinal cord of embryonic day 13 AP2β knockout mice. We hypothesize that PKD directly regulates AP2β function by serine phosphorylation and ongoing studies are being conducted to determine phosphorylation sites in AP2β directly regulated by PKD. Taken together, we demonstrate AP2β negatively regulates VEGFR-2 transcription and VEGFR-2 is a major downstream target of PKD. Our findings describing how PKD regulates angiogenesis may contribute to the development of therapies to improve the clinical outcome of patients afflicted by heart disease, stroke, and cancer.

scholarly journals Involvement of STAT5 in Oncogenesis

Biomedicines ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 316
Author(s):  
Clarissa Esmeralda Halim ◽  
Shuo Deng ◽  
Mei Shan Ong ◽  
Celestial T. Yap
Keyword(s):  
Cell Proliferation ◽  
Cancer Progression ◽  
Transcriptional Activity ◽  
Target Genes ◽  
Kinase Inhibitors ◽  
Cyclin D ◽  
Signal Transducer ◽  
Stat Proteins ◽  
Constitutive Activation ◽  
Target Molecules

Signal transducer and activator of transcription (STAT) proteins, and in particular STAT3, have been established as heavily implicated in cancer. Recently, the involvement of STAT5 signalling in the pathology of cancer has been shown to be of increasing importance. STAT5 plays a crucial role in the development of the mammary gland and the homeostasis of the immune system. However, in various cancers, aberrant STAT5 signalling promotes the expression of target genes, such as cyclin D, Bcl-2 and MMP-2, that result in increased cell proliferation, survival and metastasis. To target constitutive STAT5 signalling in cancers, there are several STAT5 inhibitors that can prevent STAT5 phosphorylation, dimerisation, or its transcriptional activity. Tyrosine kinase inhibitors (TKIs) that target molecules upstream of STAT5 could also be utilised. Consequently, since STAT5 contributes to tumour aggressiveness and cancer progression, inhibiting STAT5 constitutive activation in cancers that rely on its signalling makes for a promising targeted treatment option.

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