scholarly journals Gain-of-function genetic screen of the kinome reveals BRSK2 as an inhibitor of the NRF2 transcription factor

2020 ◽  
Vol 133 (14) ◽  
pp. jcs241356 ◽  
Author(s):  
Tigist Y. Tamir ◽  
Brittany M. Bowman ◽  
Megan J. Agajanian ◽  
Dennis Goldfarb ◽  
Travis P. Schrank ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Protein Kinase ◽  
Human Cancer ◽  
Antioxidant Response ◽  
Genetic Screen ◽  
Related Factor ◽  
Dependent Manner ◽  
Gain Of Function ◽  
Protein Levels ◽  
Nrf2 Protein

ABSTRACTNuclear factor erythroid 2-related factor 2 (NFE2L2, also known as NRF2) is a transcription factor and master regulator of cellular antioxidant response. Aberrantly high NRF2-dependent transcription is recurrent in human cancer, but conversely NRF2 activity diminishes with age and in neurodegenerative and metabolic disorders. Although NRF2-activating drugs are clinically beneficial, NRF2 inhibitors do not yet exist. Here, we describe use of a gain-of-function genetic screen of the kinome to identify new druggable regulators of NRF2 signaling. We found that the under-studied protein kinase brain-specific kinase 2 (BRSK2) and the related BRSK1 kinases suppress NRF2-dependent transcription and NRF2 protein levels in an activity-dependent manner. Integrated phosphoproteomics and RNAseq studies revealed that BRSK2 drives 5′-AMP-activated protein kinase α2 (AMPK) signaling and suppresses the mTOR pathway. As a result, BRSK2 kinase activation suppresses ribosome-RNA complexes, global protein synthesis and NRF2 protein levels. Collectively, our data illuminate the BRSK2 and BRSK1 kinases, in part by functionally connecting them to NRF2 signaling and mTOR. This signaling axis might prove useful for therapeutically targeting NRF2 in human disease.This article has an associated First Person interview with the first author of the paper.

scholarly journals Gain-of-function genetic screen of the kinome reveals BRSK2 as an inhibitor of the NRF2 transcription factor

2019 ◽  
Author(s):  
Tigist Y Tamir ◽  
Brittany M Bowman ◽  
Megan J Agajanian ◽  
Dennis Goldfarb ◽  
Travis P Schrank ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Protein Synthesis ◽  
Human Cancer ◽  
Genetic Screen ◽  
Mtor Signaling ◽  
Negative Regulator ◽  
Dependent Manner ◽  
Gain Of Function ◽  
Protein Levels ◽  
Nrf2 Protein

AbstractNFE2L2/NRF2 is a transcription factor and master regulator of cellular antioxidant response. Aberrantly high NRF2-dependent transcription is recurrent in human cancer, and conversely NRF2 protein levels as well as activity is diminished with age and in neurodegenerative disorders. Though NRF2 activating drugs are clinically beneficial, NRF2 inhibitors do not yet exist. Here we used a gain-of-function genetic screen of the kinome to identify new druggable regulators of NRF2 signaling. We found that the understudied protein kinase Brain Specific Kinase 2 (BRSK2) and the related BRSK1 kinases suppress NRF2-dependent transcription and NRF2 protein levels in an activity-dependent manner. Integrated phosphoproteomics and RNAseq studies revealed that BRSK2 drives AMPK activation and suppresses mTOR signaling. As a result, BRSK2 kinase activation suppressed ribosome-RNA complexes, global protein synthesis, and NRF2 protein levels. Collectively, our data establish the catalytically active BRSK2 kinase as a negative regulator of NRF2 via the AMPK/mTOR signaling. This signaling axis may prove useful for therapeutically targeting NRF2 in human diseases.Summary StatementBRSK2 suppresses NRF2 signaling by inhibiting protein synthesis through mTOR downregulation.

Mifepristone-inducible recombinant adenovirus attenuates paraquat-induced lung injury in rats

2014 ◽  
Vol 34 (1) ◽  
pp. 32-43 ◽  
Author(s):  
G-L Hong ◽  
Q-Q Cai ◽  
J-P Tan ◽  
X-Z Jiang ◽  
G-J Zhao ◽  
...  
Keyword(s):  
Lung Injury ◽  
Recombinant Adenovirus ◽  
Antioxidant Response ◽  
Nuclear Factor Κb ◽  
Heme Oxygenase 1 ◽  
Related Factor ◽  
Dependent Manner ◽  
Nuclear Factor ◽  
Quinone Oxidoreductase ◽  
Protein Levels

Objective: To investigate the effects of overexpression of nuclear factor E2-related factor-2 (NRF2) on lung injury in rats exposed to paraquat (PQ) poisoning. Methods: A mifepristone (RU486)-inducible recombinant adenoviral vector carrying the human NRF2 gene (Ad-RUNRF2) was constructed and transfected via airway into the rats 7 days before the administration of RU486. Rats were orally challenged with PQ at 20 mg/kg 24 h after the injection of RU486. On days 0.5, 3 and 21 after PQ poisoning, the expressions of NRF2 and cytokines related to inflammation and oxidation in lung tissue were examined. Results: RU486 remarkably enhanced NRF2 mRNA and NRF2 protein levels in Ad-RUNRF2-transfected rats in a dose-dependent manner ( p < 0.01). PQ stimulated compensatory overexpression of NRF2, heme oxygenase 1 (HO-1) and NAD(P)H quinone oxidoreductase 1 (NQO-1) in lungs on days 0.5 and 3 after exposure ( p < 0.05), but depleted the expression of catalase (CAT), glutathione peroxidase (GSH-Px) and glutathione (GSH), with an increased malondialdehyde (MDA) ( p < 0.05). However, pretreatment with Ad-RUNRF2 and RU486 strongly enhanced the expression levels of NRF2, HO-1, NQO-1, CAT and GSH-Px in the lungs of PQ intoxicated rats, with increased GSH and decreased MDA ( p < 0.05). Pretreatment with Ad-RUNRF2 and RU486 also strongly suppressed the PQ-induced activation of nuclear factor κB (NF-κB) and decreased the levels of tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6). In addition, Ad-RUNRF2 and RU486 induction significantly reduced PQ-induced pathological changes in lungs and attenuated lung oedema and protein leakage caused by PQ ( p < 0.05). Conclusion: RU486-induced overexpression of NRF2 in lungs transfected with Ad-RUNRF2 can ameliorate PQ-induced lung injury by the activation of the NRF2-antioxidant response element (ARE) pathway.

Platelet-Rich and Platelet-Poor Plasma Might Play Supportive Roles in Cancer Cell Culture: A Replacement for Fetal Bovine Serum?

2021 ◽  
Vol 21 ◽  
Author(s):  
Mehdi Talebi ◽  
Mousa Vatanmakanian ◽  
Ali Mirzaei ◽  
Yaghoub Barfar ◽  
Maryam Hemmatzadeh ◽  
...  
Keyword(s):  
Cell Culture ◽  
Cell Growth ◽  
Cancer Cell ◽  
Human Cancer ◽  
High Price ◽  
Dependent Manner ◽  
Platelet Poor Plasma ◽  
Protein Levels ◽  
Healthy Donors ◽  
Regulatory Functions

Background: Platelet-rich (PRP) and Platelet-poor plasma (PPP) are widely used in research and clinical platforms mainly due to their capacities to enhance cell growth. Although short half-life (5 days) and the high price of platelet products pose challenges regarding their usage, they maintain the growth regulatory functions for weeks. Thus, we aimed to assess the supplementary values of these products in human CCRF-CEM cancer cells. Mechanistically, we also checked if the PRP/PPP treatment enhances YKL-40 expression as a known protein regulating cell growth. Methods: The PRP/PPP was prepared from healthy donors using manual stepwise centrifugation and phase separation. The viability of the cells treated with gradient PRP/PPP concentrations (2, 5, 10, and 15%) was measured by the MTT assay. The YKL-40 mRNA and protein levels were assessed using qRT-PCR and western blotting. The data were compared to FBS-treated cells. Result: Our findings revealed that the cells treated by PRP/PPP not only were morphologically comparable to those treated by FBS but also, they showed greater viability at the concentrations of 10 and 15%. Moreover, it was shown that PRP/PPP induce cell culture support, at least in part, via inducing YKL-40 expression at both mRNA and protein levels in a time- and dose-dependent manner. Conclusion: Collectively, by showing cell culture support comparable to FBS, the PRP/PPP might be used as good candidates to supplement the cancer cell culture and overcome concerns regarding the use of FBS as a non-human source in human cancer research.

scholarly journals Concomitant Nrf2- and ATF4-activation by Carnosic Acid Cooperatively Induces Expression of Cytoprotective Genes

2019 ◽  
Vol 20 (7) ◽  
pp. 1706 ◽  
Author(s):  
Junsei Mimura ◽  
Atsushi Inose-Maruyama ◽  
Shusuke Taniuchi ◽  
Kunio Kosaka ◽  
Hidemi Yoshida ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Carnosic Acid ◽  
Related Factor ◽  
Dependent Manner ◽  
Independent Manner ◽  
Antioxidant Genes ◽  
Activating Transcription Factor 4 ◽  
Activating Transcription Factor ◽  
Rosmarinus Officinalis L ◽  
Ngf Gene

: Carnosic acid (CA) is a phytochemical found in some dietary herbs, such as Rosmarinus officinalis L., and possesses antioxidative and anti-microbial properties. We previously demonstrated that CA functions as an activator of nuclear factor, erythroid 2 (NF-E2)-related factor 2 (Nrf2), an oxidative stress-responsive transcription factor in human and rodent cells. CA enhances the expression of nerve growth factor (NGF) and antioxidant genes, such as HO-1 in an Nrf2-dependent manner in U373MG human astrocytoma cells. However, CA also induces NGF gene expression in an Nrf2-independent manner, since 50 μM of CA administration showed striking NGF gene induction compared with the classical Nrf2 inducer tert-butylhydroquinone (tBHQ) in U373MG cells. By comparative transcriptome analysis, we found that CA activates activating transcription factor 4 (ATF4) in addition to Nrf2 at high doses. CA activated ATF4 in phospho-eIF2α- and heme-regulated inhibitor kinase (HRI)-dependent manners, indicating that CA activates ATF4 through the integrated stress response (ISR) pathway. Furthermore, CA activated Nrf2 and ATF4 cooperatively enhanced the expression of NGF and many antioxidant genes while acting independently to certain client genes. Taken together, these results represent a novel mechanism of CA-mediated gene regulation evoked by Nrf2 and ATF4 cooperation.

scholarly journals Curcumin Protects Human Keratinocytes against Inorganic Arsenite-Induced Acute Cytotoxicity through an NRF2-Dependent Mechanism

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Rui Zhao ◽  
Bei Yang ◽  
Linlin Wang ◽  
Peng Xue ◽  
Baocheng Deng ◽  
...  
Keyword(s):  
Inorganic Arsenic ◽  
Human Keratinocytes ◽  
Antioxidant Response ◽  
Nuclear Accumulation ◽  
Related Factor ◽  
High Concentration ◽  
Low Concentrations ◽  
Acute Cytotoxicity ◽  
Nrf2 Protein ◽  
Dependent Mechanism

Human exposure to inorganic arsenic leads to various dermal disorders, including hyperkeratosis and skin cancer. Curcumin is demonstrated to induce remarkable antioxidant activity in a variety of cells and tissues. The present study aimed at identifying curcumin as a potent activator of nuclear factor erythroid 2-related factor 2 (NRF2) and demonstrating its protective effect against inorganic arsenite- (iAs3+-) induced cytotoxicity in human keratinocytes. We found that curcumin led to nuclear accumulation of NRF2 protein and increased the expression of antioxidant response element- (ARE-) regulated genes in HaCaT keratinocytes in concentration- and time-dependent manners. High concentration of curcumin (20 μM) also increased protein expression of long isoforms of NRF1. Treatment with low concentrations of curcumin (2.5 or 5 μM) effectively increased the viability and survival of HaCaT cells against iAs3+-induced cytotoxicity as assessed by the MTT assay and flow cytometry and also attenuated iAs3+-induced expression of cleaved caspase-3 and cleaved PARP protein. Selective knockdown ofNRF2orKEAP1by lentiviral shRNAs significantly diminished the cytoprotection conferred by curcumin, suggesting that the protection against iAs3+-induced cytotoxicity is dependent on the activation of NRF2. Our results provided a proof of the concept of using curcumin to activate the NRF2 pathway to alleviate arsenic-induced dermal damage.

scholarly journals Oregano Essential Oil Induces SOD1 and GSH Expression through Nrf2 Activation and Alleviates Hydrogen Peroxide-Induced Oxidative Damage in IPEC-J2 Cells

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Yi Zou ◽  
Jun Wang ◽  
Jian Peng ◽  
Hongkui Wei
Keyword(s):  
Hydrogen Peroxide ◽  
Essential Oil ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Cell Damage ◽  
Antioxidant Response ◽  
Related Factor ◽  
Protective Effects ◽  
Oregano Essential Oil ◽  
Protein Levels

Oregano essential oil (OEO) has long been used to improve the health of animals, particularly their intestinal health. The health benefits of OEO are generally attributed to antioxidative actions, but the mechanisms remain unclear. Here, we investigate the antioxidative effects of OEO and their underlying molecular mechanisms in porcine small intestinal epithelial (IPEC-J2) cells. We found that OEO treatment prior to hydrogen peroxide (H2O2) exposure increased cell viability and prevented lactate dehydrogenase (LDH) release into the medium. H2O2-induced reactive oxygen species (ROS) and malondialdehyde (MDA) were remarkably suppressed by OEO. OEO dose-dependently increased mRNA and protein levels of the nuclear factor-erythroid 2-related factor-2 (Nrf2) target genes Cu/Zn-superoxide dismutase (SOD1) and g-glutamylcysteine ligase (GCLC, GLCM), as well as intracellular concentrations of SOD1 and glutathione. OEO also increased intranuclear expression of Nrf2 and the activity of an antioxidant response element reporter plasmid in IPEC-J2 cells. The OEO-induced expression of Nrf2-regulated genes and increased SOD1 and glutathione concentrations in IPEC-J2 cells were reduced by Nrf2 small interfering (si) RNAs, counteracting the protective effects of OEO against oxidative stress in IPEC-J2 cells. Our results suggest that OEO protects against H2O2-induced IPEC-J2 cell damage by inducing Nrf2 and related antioxidant enzymes.

Requirement of the E2F3 Transcription Factor for BCR/ABL Leukemogenesis.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 33-33
Author(s):  
Anna M. Eiring ◽  
Paolo Neviani ◽  
Ramasamy Santhanam ◽  
Joshua J. Oaks ◽  
Ji Suk Chang ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Transcription Factor ◽  
Blast Crisis ◽  
Scid Mice ◽  
Myelogenous Leukemia ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Hnrnp A1 ◽  
Protein Levels ◽  
Abl Kinase

Abstract Several RNA binding proteins (RBPs) have been implicated in the progression of chronic myelogenous leukemia (CML) from the indolent chronic phase to the aggressively fatal blast crisis. In the latter phase, expression and function of specific RBPs are altered at transcriptional or post-translational levels by the increased constitutive kinase activity of the BCR/ABL oncoprotein, resulting in enhanced resistance to apoptotic stimuli, growth advantage and differentiation arrest of CD34+ CML blast crisis (CML-BC) progenitors. In the current study, we identified by RIP (RNA immunoprecipitation)-mediated microarray analysis that mRNA encoding the E2F3 transcription factor associates to the BCR/ABL-regulated RBP hnRNP A1. Moreover, RNA electrophoretic mobility shift and UV-crosslinking assays revealed that hnRNP A1 interacts with E2F3 mRNA through a binding site located in the 3’UTR of both human and mouse E2F3 mRNA. Accordingly, E2F3 protein levels were upregulated in BCR/ABL-transformed myeloid precursor cell lines compared to parental cells in a BCR/ABL-kinase- and hnRNP A1 shuttling-dependent manner. In fact, treatment of BCR/ABL-expressing myeloid precursors with the kinase inhibitor Imatinib (2mM, 24 hr) or introduction of a dominant-negative shuttling-deficient hnRNP A1 protein (NLS-A1) markedly reduced E2F3 protein and mRNA levels. Similarly, upregulation of BCR/ABL expression/activity in the doxycycline inducible TonB2.10 cell line resulted in increased E2F3 protein expression. BCR/ABL kinase-dependent induction of E2F3 protein levels was also detected in CML-BCCD34+ compared to CML-CPCD34+ progenitors from paired patient samples and to normal CD34+ bone marrow samples. Importantly, the in vitro clonogenic potential of primary mouse BCR/ABL+ lineage negative (Lin−) progenitors was markedly impaired in BCR/ABL+ E2F3−/− compared to BCR/ABL-transduced E2F3+/+ myeloid progenitors and upon shRNA-mediated downregulation of E2F3 expression (90% inhibition, P<0.001). Furthermore, subcutaneous injection of shE2F3-expressing BCR/ABL+ cells into SCID mice markedly impaired in vivo tumorigenesis (>80% reduction in tumor burden, P<0.01). Accordingly, BCR/ABL leukemogenesis was strongly inhibited in SCID mice intravenously injected with E2F3 shRNA-expressing 32D-BCR/ABL cells and in mice transplanted with BCR/ABL-transduced Lin− bone marrow cells from E2F3−/− mice. Specifically, we demonstrate that reduced or absent levels of E2F3 resulted in dramatically decreased numbers of circulating BCR/ABL+ cells as determined by nested RT-PCR at 4 weeks post-injection (P=0.0001), normal splenic architecture and bone marrow cellularity and the absence of infiltrating myeloid blasts into non-hematopoietic compartments (i.e. liver). By contrast, SCID mice transplanted with vector-transduced 32D-BCR/ABL cells or BCR/ABL+ E2F3+/+ Lin− BM progenitors showed signs of an overt acute leukemia-like process with blast infiltration of hematopoietic and non-hematopoietic organs. Altogether, these data outline the importance of E2F3 expression for BCR/ABL leukemogenesis and characterize a new potential therapeutic target for the treatment of patients with advanced phase CML.

High-Throughput RNA Interference Screening Identifies Synthetic Lethality Between Oncogenic KRAS Dependency and Suppression of STK33

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3806-3806
Author(s):  
Claudia Scholl ◽  
Stefan Frohling ◽  
Ian F. Dunn ◽  
David A. Barbie ◽  
Anna C. Schinzel ◽  
...  
Keyword(s):  
Rna Interference ◽  
Protein Kinase ◽  
Cell Viability ◽  
Cell Lines ◽  
Cancer Cell ◽  
High Throughput ◽  
Synthetic Lethality ◽  
Human Cancer ◽  
Cancer Cell Lines ◽  
Dependent Manner

Abstract Activating RAS mutations are among the most common pathogenetic events in a broad spectrum of hematologic malignancies and epithelial tumors. However, oncogenic RAS has thus far not proven to be a tractable target for therapeutic intervention. An alternative to direct targeting of known oncogenes is to perform “synthetic lethality” screens to identify genes that are selectively required for cell viability in the context of specific cancer-causing mutations. Using this approach, we have discovered a synthetic lethal interaction between mutant KRAS, the most frequently mutated oncogene in human cancer, and inactivation of the gene encoding the STK33 serine/threonine protein kinase. To identify genes that are essential for cell viability in the context of mutant KRAS, we performed high-throughput loss-of-function RNA interference (RNAi) screens in eight human cancer cell lines (mutant KRAS, n=4; wildtype KRAS, n=4), representing seven different tumor types (acute myeloid leukemia, multiple myeloma, colon cancer, breast cancer, ovarian cancer, prostate cancer, glioblastoma), as well as normal human fibroblasts and mammary epithelial cells. We screened each cell line with a subset of the short hairpin RNA (shRNA) library developed by the RNAi Consortium (http://www.broad.mit.edu/genome_bio/trc/rnai.html) that consists of 5,024 individual shRNA constructs targeting 1,011 human genes, including the majority of known and putative protein kinase and phosphatase genes and a selection of known cancer-related genes. In these cell lines, suppression of STK33 preferentially inhibited the viability and proliferation of cells that were dependent on mutant KRAS. The differential requirement for STK33 based on oncogenic KRAS dependency was confirmed in 16 additional cell lines using in vitro transformation assays and human tumor xenograft models. Biochemical analyses support the hypothesis that STK33 promotes cell growth and survival in a kinase activity-dependent manner by regulating the activity of S6K1 as well as BAD-induced apoptosis selectively in mutant KRAS-dependent cells. Notably, molecular genetic characterization of cancer cell lines and analysis of patient-derived genomic data sets indicate that STK33 is not frequently mutated or overexpressed in human tumors. These observations identify STK33 as a potential target for the treatment of mutant KRAS-driven cancers that may have a broad therapeutic index in normal versus malignant cells, and illustrate the potential of RNAi for discovering critical functional dependencies created by oncogenic mutations that cannot be identified using other genomic technologies.

scholarly journals Parathyroid Hormone Increases Activating Transcription Factor 4 Expression and Activity in Osteoblasts: Requirement for Osteocalcin Gene Expression

Endocrinology ◽  
2008 ◽  
Vol 149 (4) ◽  
pp. 1960-1968 ◽  
Author(s):  
Shibing Yu ◽  
Renny T. Franceschi ◽  
Min Luo ◽  
Xiaoyan Zhang ◽  
Di Jiang ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Protein Kinase ◽  
Transcriptional Activity ◽  
De Novo ◽  
Dependent Manner ◽  
Specific Element ◽  
Activating Transcription Factor 4 ◽  
Activating Transcription Factor ◽  
Transcription Factor 4 ◽  
Expression And Activity

PTH is an important peptide hormone regulator of calcium homeostasis and osteoblast function. However, its mechanism of action in osteoblasts is poorly understood. Our previous study demonstrated that PTH activates mouse osteocalcin (Ocn) gene 2 promoter through the osteoblast-specific element 1 site, a recently identified activating transcription factor-4 (ATF4) -binding element. In the present study, we examined effects of PTH on ATF4 expression and activity as well as the requirement for ATF4 in the regulation of Ocn by PTH. Results show that PTH elevated levels of ATF4 mRNA and protein in a dose- and time-dependent manner. This PTH regulation requires transcriptional activity but not de novo protein synthesis. PTH also increased binding of nuclear extracts to osteoblast-specific element 1 DNA. PTH stimulated ATF4-dependent transcriptional activity mainly through protein kinase A with a lesser requirement for protein kinase C and MAPK/ERK pathways. Lastly, PTH stimulation of Ocn expression was lost by small interfering RNA down-regulation of ATF4 in MC-4 cells and Atf4−/− bone marrow stromal cells. Collectively, these studies for the first time demonstrate that PTH increases ATF4 expression and activity and that ATF4 is required for PTH induction of Ocn expression in osteoblasts.

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