The TRIM26-SOX2 Ubiquitin Signaling Axis Regulates the Maintenance and Tumorigenicity of Glioblastoma Stem-like Cells

Abstract INTRODUCTION Glioblastomas harbor inter and intratumoral genetic diversity, posing a challenge for targeted therapies. A major question is whether shared mechanisms might control the malignant phenotypes of genetically diverse glioblastoma cells. We reasoned that ubiquitin-dependent regulation of pluripotency-related transcription factor SOX2, which is indispensable for the maintenance of tumorigenic glioblastoma stem-like cells (GSC), may represent one such mechanism. TRIM26, an E3-ubiquitin ligase with immune-related functions, is highly expressed in glioblastoma tumors compared to normal brain. Immunoprecipitation followed by mass spectrometry suggested TRIM26 interacts with SOX2. We hypothesized that TRIM26 plays an essential role in GSCs by regulating SOX2 function. METHODS Direct protein-protein interactions were assessed by in vitro binding assays. In Vitro ubiquitination assays were performed. Lentiviral TRIM26 overexpression and knockdown were used to test the role of TRIM26 in regulating SOX2 stability, activity, and ubiquitination. The functional relevance of TRIM26 in GSCs was assessed by in Vitro self-renewal and in Vivo tumorigenicity assays. RESULTS We found that TRIM26 directly interacts with SOX2 via the C-terminal PRY-SPRY domain. Unexpectedly, TRIM26 overexpression resulted in decreased SOX2 polyubiquitination in cells. In line with this observation, TRIM26 knockdown in GSCs decreased SOX2 protein stability without changing SOX2 mRNA levels. Functionally, TRIM26 knockdown reduced SOX2 transcriptional activity, self-renewal, and in Vivo tumorigenicity in multiple genetically divergent GSC lines. Mechanistically, we discovered TRIM26 stabilizes SOX2 protein by competitively reducing the interaction of SOX2 with WWP2, a bonafide SOX2 E3 ligase in GSCs. Accordingly; WWP2 depletion in the setting of TRIM26 knockdown in GSCs rescued SOX2 protein levels, self-renewal, and tumorigenicity. CONCLUSION Together, these results suggest that TRIM26 maintains GSCs by protecting SOX2 from WWP2-mediated ubiquitination and subsequent proteasomal degradation. These findings raise the intriguing possibility that modulating ubiquitin-dependent regulation of SOX2 in genetically heterogeneous GSCs may represent a unifying therapeutic strategy.

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TRIM27 interacts with Iκbα to promote the growth of human renal cancer cells through regulating the NF-κB pathway

BMC Cancer ◽

10.1186/s12885-021-08562-5 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Chengwu Xiao ◽

Wei Zhang ◽

Meimian Hua ◽

Huan Chen ◽

Bin Yang ◽

...

Keyword(s):

Cell Lines ◽

Prognostic Indicator ◽

The Cancer Genome Atlas ◽

Mrna Levels ◽

Loss Of Function ◽

Protein Levels ◽

Kaplan Meier ◽

Cancer Genome Atlas

Abstract Background The tripartite motif (TRIM) family proteins exhibit oncogenic roles in various cancers. The roles of TRIM27, a member of the TRIM super family, in renal cell carcinoma (RCC) remained unexplored. In the current study, we aimed to investigate the clinical impact and roles of TRIM27 in the development of RCC. Methods The mRNA levels of TRIM27 and Kaplan–Meier survival of RCC were analyzed from The Cancer Genome Atlas database. Real-time PCR and Western blotting were used to measure the mRNA and protein levels of TRIM27 both in vivo and in vitro. siRNA and TRIM27 were exogenously overexpressed in RCC cell lines to manipulate TRIM27 expression. Results We discovered that TRIM27 was elevated in RCC patients, and the expression of TRIM27 was closely correlated with poor prognosis. The loss of function and gain of function results illustrated that TRIM27 promotes cell proliferation and inhibits apoptosis in RCC cell lines. Furthermore, TRIM27 expression was positively associated with NF-κB expression in patients with RCC. Blocking the activity of NF-κB attenuated the TRIM27-mediated enhancement of proliferation and inhibition of apoptosis. TRIM27 directly interacted with Iκbα, an inhibitor of NF-κB, to promote its ubiquitination, and the inhibitory effects of TRIM27 on Iκbα led to NF-κB activation. Conclusions Our results suggest that TRIM27 exhibits an oncogenic role in RCC by regulating NF-κB signaling. TRIM27 serves as a specific prognostic indicator for RCC, and strategies targeting the suppression of TRIM27 function may shed light on future therapeutic approaches.

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The role of RXFP2 in mediating androgen-induced inguinoscrotal testis descent in LH receptor knockout mice

Reproduction ◽

10.1530/rep-09-0518 ◽

2010 ◽

Vol 139 (4) ◽

pp. 759-769 ◽

Cited By ~ 42

Author(s):

F P Yuan ◽

X Li ◽

J Lin ◽

C Schwabe ◽

E E Büllesbach ◽

...

Keyword(s):

Mesenchymal Cell ◽

Postnatal Period ◽

Testosterone Replacement Therapy ◽

Developmental Defect ◽

Mrna Levels ◽

Lh Receptor ◽

Protein Levels ◽

Testis Descent

LH receptor knockout (LhrKO) male mice exhibit a bilateral cryptorchidism resulting from a developmental defect in the gubernaculum during the inguinoscrotal phase of testis descent, which is corrected by testosterone replacement therapy (TRT).In vivoandin vitroexperiments were conducted to investigate the roles of the androgen receptor (AR) and RXFP2 signals in regulation of gubernacular development inLhrKO animals. This study demonstrated that AR and RXFP2 proteins were expressed in the gubernaculum during the entire postnatal period. TRT normalized gubernacular RXFP2 protein levels inLhrKO mice. Organ and primary cell cultures of gubernacula showed that 5α-dihydrotestosterone (DHT) upregulated the expression ofRxfp2which was abolished by the addition of an AR antagonist, flutamide. A single s.c. testosterone injection also led to a significant increase inRxfp2mRNA levels in a time-dependent fashion inLhrKO animals. DHT, natural and synthetic insulin-like peptide 3 (INSL3), or relaxin alone did not affect proliferation of gubernacular mesenchymal cells, while co-treatments of DHT with either INSL3 or relaxin resulted in an increase in cell proliferation, and they also enhanced the mesenchymal cell differentiation toward the myogenic pathway, which included a decrease in a mesenchymal cell marker, CD44 and the expression of troponin. These effects were attenuated by the addition of flutamide, siRNA-mediatedRxfp2knockdown, or by an INSL3 antagonist. Co-administration of an INSL3 antagonist curtailed TRT-induced inguinoscrotal testis descent inLhrKO mice. Our findings indicate that the RXFP2 signaling pathway plays an important role in mediating androgen action to stimulate gubernaculum development during inguinoscrotal testis descent.

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Corilagin ameliorates schistosomiasis hepatic fibrosis through regulating IL-13 associated signal pathway in vitro and in vivo

Parasitology ◽

10.1017/s0031182016001128 ◽

2016 ◽

Vol 143 (12) ◽

pp. 1629-1638 ◽

Cited By ~ 13

Author(s):

HUA-RONG LI ◽

GANG LI ◽

MAN LI ◽

SHU-LING ZHANG ◽

HENG WANG ◽

...

Keyword(s):

Hepatic Fibrosis ◽

Quantitative Polymerase Chain Reaction ◽

Signal Pathway ◽

Signal Molecules ◽

Mrna Levels ◽

Protein Levels ◽

Set Up ◽

Inflammatory Changes

SUMMARYInterleukin (IL)-13-associated signal pathway plays an important role in schistosomiasis hepatic fibrosis. In this study we tried to investigate the effects of corilagin to ameliorate schistosomiasis hepatic fibrosis through regulating IL-13-associated signal pathway in vitro and in vivo. Cellular model was set up with hepatic stellate cells-T6 cells stimulated by rIL-13 and male Balb/c mice were infected with Schistosoma japonicum cercariaeas as animal model. Liver histological changes were observed with haematoxylin and eosin staining. Masson staining was employed to observe the change of egg granulomas. Expression of Col (collagen) and Col III were examined with Immunohistochemistry. Western bolt was employed to detect the JAK-1 and IL13Rα1 proteins. The mRNA expression of Col I, Col III, IL-13, JAK-1 and IL13Rα1 were tested by quantitative polymerase chain reaction. As a result, less inflammatory changes were found in all corilagin groups compared with model group and praziquantel group. The mRNA levels of Col I, Col III, IL-13, JAK-1 and IL13Rα1 were significantly decreased after corilagin intervention (P < 0·01). JAK-1 and IL-13Rα1 protein levels were also greatly decreased in the corilagin groups (P < 0·01). In conclusion, corilagin could ameliorate schistosomiasis hepatic fibrosis by down-regulating the expression of IL-13 and signal molecules in IL-13 pathway.

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Dissection of Mechanisms of Realgar Intervening Telomere Protein POT1, TRF1, TRF2 Expression to Regulate Telomere Dynamics in THP-1 Cells

Blood ◽

10.1182/blood.v128.22.5896.5896 ◽

2016 ◽

Vol 128 (22) ◽

pp. 5896-5896

Author(s):

Rui-Rong Xu ◽

Nan-Xin Song ◽

Xiao-Long Wu ◽

Si-Yuan Cui ◽

Zhen-Zhen Wang ◽

...

Keyword(s):

Theoretical Basis ◽

Cell Cycle Distribution ◽

G1 Arrest ◽

Mrna Levels ◽

Protein Levels ◽

Qpcr Analysis ◽

Telomere Protein ◽

Telomere Dynamics

Abstract Objective: To observe the mechanisms of realgar intervening telomere protein POT1, TRF1, TRF2 expression to regulate telomere dynamics in THP-1 cells, and elucidate the experimental and theoretical basis for realgar targeted threapy of AML. Methods: 1.In vitro: (1)Cultured human acute myeloid leukemia THP-1 cells. (2), The cells were incubated in absence or presence of increasing concentration of realgar for 24/48 h, from which determined the IC50. Cell viability was tested by CCK-8 assay. (3)Apoptotic rate and cell cycle distribution were tested by FCM. (4)Each group of POT1, TRF1, TRF2 protein levels were tested by western-blot analysis. (5)Each group of POT1,TRF1,TRF2 mRNA levels were tested by RT-qPCR analysis. 2.In vivo: (1)Established THP-1 model in NOD/SCID mice, and the mouse were treated by realgar. (2)All the mouse were killed by institutionally approved method after 3 weeks. The apoptotic rate and cell cycle distribution of mice spleen cells were examined by FCM. (3)The changes of POT1, TRF1, TRF2 protein levels in organic tissue were detected by IHC. Results: 1.In vitro: (1)CCK-8 assay showed that after treated by realgar, THP-1 cells growth were inhibited and the cell viability decreased in a dose- and time- dependent manner, IC50 was 0.023μg/mL. Therefore, we choose a medium concentration was 0.015μg/mL (lower than IC50) at 48h. (2)Our study demonstrated that after treatment for 48h, the apoptotic rate and the G1 arrest of these THP-1 cell increased, compared with control group. (3)As shown by western blot analysis, compared with controls, realgar group POT1, TRF1 protein levels significantly increaesed and TRF2 decreased(P<0.01). (4) As shown by by RT-qPCR analysis, POT1, TRF1, TRF2 mRNA levels were consistent with their protein levels. 2.In vivo: (1) The THP-1/NOD-SCID model was established, and survival curve showed that compared with controls, realgar group mouse had longer life span(P<0.01). (2) The results of FCM showed that after treatment of realgar, the rate of THP-1 cell apoptosis and G1 arrest significantly increased(P<0.01). (3) The results of IHC showed that compared with controls, POT1, TRF1 protein levels significantly increased and TRF2 decreased in realgar group mouse(P<0.01). Conclusion: In vitro and in vivo studies results indicated that realgar could significantly prolong the life span of the THP-1/NOD-SCID mice, inhibit proliferation and induce apoptosis of THP-1 cell, and regulate telomere dynamics through intervening THP-1 cell telomere protein POT1, TRF1, TRF2 expression. Our studies results provided experimental and theoretical basis for realgar targeted threapy of AML. Disclosures No relevant conflicts of interest to declare.

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Epigenetic Regulator KDM4D Restricts Tumorigenesis via Modulating SYVN1/HMGB1 Ubiquitination Axis in Esophageal Squamous Cell Carcinoma

Frontiers in Oncology ◽

10.3389/fonc.2021.761346 ◽

2021 ◽

Vol 11 ◽

Author(s):

Wenjian Yao ◽

Jianjun Wang ◽

Li Zhu ◽

Xiangbo Jia ◽

Lei Xu ◽

...

Keyword(s):

Tumor Growth ◽

Bioinformatic Analysis ◽

Soft Agar ◽

Tumor Xenograft ◽

Mrna Levels ◽

Protein Levels ◽

Novel Biomarkers ◽

Underlying Mechanisms

BackgroundIncreasing researches have been reported that epigenetic alterations play critical roles in ESCC development. However, the role of the histone demethylase KDM4D in ESCC tumorigenesis is poorly investigated. This study aims to discover the underlying mechanisms between KDM4D and ESCC progression.MethodsCCK-8 assays, clone formation assay and soft-agar assays were performed to assess cell proliferation. Transwell assay was utilized to assess cell migration efficiency, while sphere formation assay was used to evaluate the cell self-renewal ability. Bioinformatic analysis was conducted to identify prognostic factors and predict the potential E3 ubiquitin ligases. In vitro ubiquitination assay was conducted to confirm the regulations between SYVN1 and HMGB1. The mRNA levels or protein levels of genes were detected by real-time PCR and western blot analysis. In vivo tumor xenograft models were used to determine whether the HMGB1 inhibition affected the malignant features of ESCC cells.ResultEpigenome screening and low-throughput validations highlighted that KDM4D is a tumor suppressor in ESCC. KDM4D expressed lowly in tumors that predicts poor prognosis. KDM4D deficiency significantly enhanced tumor growth, migration and stemness. Mechanistically, KDM4D transcriptionally activates SYVN1 expressions via H3K9me3 demethylation at the promoter region, thereby triggering the ubiquitin-dependent degradation of HMGB1. Low KDM4D depended on accumulated HMGB1 to drive ESCC progression and aggressiveness. Targeting HMGB1 (Glycyrrhizin) could remarkably suppress ESCC tumor growth in vitro and in vivo, especially in KDM4D-deficient cells.ConclusionsWe systematically identified KDM4D/SYVN1/HMGB1 axis in ESCC progression, proving novel biomarkers and potential therapeutic targets.

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Mutations in conserved residues of the myosin chaperone UNC-45 result in both reduced stability and chaperoning activity

10.1101/2021.05.07.443121 ◽

2021 ◽

Author(s):

Taylor Moncrief ◽

Courtney J Matheny ◽

Ivana Gaziova ◽

John Miller ◽

Hiroshi Qadota ◽

...

Keyword(s):

Protein Stability ◽

Protein Interactions ◽

Muscle Development ◽

Thick Filament ◽

Chaperone Activity ◽

Missense Mutations ◽

Protein Levels ◽

Conserved Regions

Proper muscle development and function depends on myosin being properly folded and integrated into the thick filament structure. For this to occur the myosin chaperone UNC-45, or UNC-45B, must be present and able to chaperone myosin. Here we use a combination of in vivo C. elegans experiments and in vitro biophysical experiments to analyze the effects of six missense mutations in conserved regions of UNC-45/UNC-45B. We found that the phenotype of paralysis and disorganized thick filaments in 5/6 of the mutant nematode strains can likely be attributed to both reduced steady state UNC-45 protein levels and reduced chaperone activity. Interestingly, the biophysical assays performed on purified proteins show that all of the mutations result in reduced myosin chaperone activity but not overall protein stability. This suggests that these mutations only cause protein instability in the in vivo setting and that these conserved regions may be involved in UNC-45 protein stability/ regulation via post translational modifications, protein-protein interactions, or some other unknown mechanism.

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Regulation of uridine diphosphate-glucuronosyltransferase 1A expression by miRNA-214-5p and miRNA-486-3p

Epigenomics ◽

10.2217/epi-2020-0244 ◽

2021 ◽

Author(s):

Stefan Paulusch ◽

Sandra Kalthoff ◽

Steffen Landerer ◽

Christian Jansen ◽

Robert Schierwagen ◽

...

Keyword(s):

Liver Fibrosis ◽

Potential Risk ◽

Mrna Levels ◽

Uridine Diphosphate ◽

Protein Levels ◽

Huh7 Cells ◽

Potential Risk Factors ◽

Cirrhotic Patients

Aim: This study aimed to identify novel miRNAs (miRs) as regulators of UGT1A gene expression and to evaluate them as potential risk factors for the development of liver fibrosis/cirrhosis. Materials & methods: miRNA target sites in UDP-glucuronosyltransferase 1A (UGT1A) 3′-UTR were predicted and confirmed by luciferase assays, quantitative real-time PCR and western blot using HEK293, HepG2 and Huh7 cells. UGT1A and miRNA expression were analyzed in cirrhotic patients and a mouse model of alcoholic liver fibrosis. Results: miR-214-5p and miR-486-3p overexpression reduced UGT1A mRNA, protein levels and enzyme activity in HepG2 and Huh7 cells. miR-486-3p was upregulated in cirrhotic patients and fibrotic mice livers, whereas UGT1A mRNA levels were reduced. Conclusion: In conclusion, we identified two novel miRNAs capable to repress UGT1A expression in vitro and in vivo. Furthermore, miR-486-3p may represent a potential risk factor for the development or progression of liver fibrosis/cirrhosis by means of a reduced UGT1A-mediated detoxification activity.

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Acetylation of GATA-1 Is Required for Chromatin Occupancy.

Blood ◽

10.1182/blood.v108.11.1179.1179 ◽

2006 ◽

Vol 108 (11) ◽

pp. 1179-1179 ◽

Cited By ~ 1

Author(s):

Janine M. Lamonica ◽

Christopher R. Vakoc ◽

Gerd A. Blobel

Keyword(s):

Protein Interactions ◽

Dependent Manner ◽

Protein Levels ◽

Defective Mutant ◽

Cellular Target ◽

Stable Association ◽

Peptide Affinity

Abstract All three hematopoietic GATA transcription factors GATA-1, GATA-2, and GATA-3 are acetylated, although the in vivo role of this modification remains unclear. It has been proposed that acetylation of GATA-1 increases its affinity for DNA in vitro, although this finding has not been observed by others. To study the role of GATA-1 acetylation, we examined the functions of an acetylation-defective mutant of GATA-1 in maturing erythroid cells. We found that removal of the acetylation sites in GATA-1 largely abrogates its biological activity but does not impair its nuclear localization, steady state protein levels, or its ability to bind naked GATA elements in vitro. However, chromatin immunoprecipitation (ChIP) experiments revealed that mutant GATA-1 was dramatically impaired in binding to its cellular target sites in vivo, including genes that are normally activated (α- and β-globin, EKLF, FOG-1, Band3, and AHSP) and repressed (GATA-2 and c-kit) by GATA-1. Together, these results suggest that acetylation is required for GATA-1 chromatin occupancy. These findings point to a novel function for transcription factor acetylation, perhaps by facilitating protein interactions required for stable association with chromatin templates in vivo. To identify proteins that interact with acetylated GATA-1, we performed peptide affinity chromatography using acetylated GATA-1 peptides. Using this technique coupled with mass spectrometry, several proteins that bind to GATA-1 peptides in an acetylation-dependent manner were identified. The identified proteins contain known acetyl-lysine binding modules (bromodomains) consistent with their binding properties. The in vivo role of these proteins with regard to GATA-1 function is being examined and will be discussed.

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BRF1 Protein Turnover and mRNA Decay Activity Are Regulated by Protein Kinase B at the Same Phosphorylation Sites

Molecular and Cellular Biology ◽

10.1128/mcb.01099-06 ◽

2006 ◽

Vol 26 (24) ◽

pp. 9497-9507 ◽

Cited By ~ 62

Author(s):

Don Benjamin ◽

Martin Schmidlin ◽

Lu Min ◽

Brigitte Gross ◽

Christoph Moroni

Keyword(s):

Protein Kinase ◽

Mrna Decay ◽

Protein Kinase B ◽

Proteasomal Degradation ◽

Mrna Levels ◽

Cell Compartment ◽

Protein Levels ◽

Dependent Protein

ABSTRACT BRF1 posttranscriptionally regulates mRNA levels by targeting ARE-bearing transcripts to the decay machinery. We previously showed that protein kinase B (PKB) phosphorylates BRF1 at Ser92, resulting in binding to 14-3-3 and impairment of mRNA decay activity. Here we identify an additional regulatory site at Ser203 that cooperates in vivo with Ser92. In vitro kinase labeling and wortmannin sensitivity indicate that Ser203 phosphorylation is also performed by PKB. Mutation of both serines to alanine uncouples BRF1 from PKB regulation, leading to constitutive mRNA decay even in the presence of stabilizing signals. BRF1 protein is labile because of proteasomal degradation (half-life, <3 h) but becomes stabilized upon phosphorylation and is less stable in PKBα−/− cells. Surprisingly, phosphorylation-dependent protein stability is also regulated by Ser92 and Ser203, with parallel phosphorylation required at these sites. Phosphorylation-dependent binding to 14-3-3 is abolished only when both sites are mutated. Cell compartment fractionation experiments support a model in which binding to 14-3-3 sequesters BRF1 through relocalization and prevents it from executing its mRNA decay activity, as well as from proteasomal degradation, thereby maintaining high BRF1 protein levels that are required to reinstate decay upon dissipation of the stabilizing signal.

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Role of the TNF pathway in the progression of diabetic nephropathy in KK-Ay mice

AJP Renal Physiology ◽

10.1152/ajprenal.00509.2013 ◽

2014 ◽

Vol 306 (11) ◽

pp. F1335-F1347 ◽

Cited By ~ 32

Author(s):

Keisuke Omote ◽

Tomohito Gohda ◽

Maki Murakoshi ◽

Yu Sasaki ◽

Saiko Kazuno ◽

...

Keyword(s):

Diabetic Nephropathy ◽

Early Stage ◽

Mrna Levels ◽

Monocyte Chemoattractant Protein 1 ◽

Protein Levels ◽

Tnf Α ◽

Soluble Tnf Receptor

Chronic inflammation promotes the progression of diabetic nephropathy (DN). However, the role of TNF-α remains unclear. The objectives of the present study were to examine whether TNF-α inhibition with a soluble TNF receptor (TNFR)2 fusion protein, i.e., etanercept (ETN), improves the early stage of DN in the type 2 diabetic model of the KK-Ay mouse and to also investigate which TNF pathway, TNFR1 or TNFR2, is predominantly involved in the progression of this disease. ETN was injected intraperitoneally into mice for 8 wk. Renal damage was evaluated by immunohistochemistry, Western blot analysis, and/or real-time PCR. In vitro, mouse tubular proximal cells were stimulated by TNF-α and/or high glucose (HG) and treated with ETN. ETN dramatically improved not only albuminuria but also glycemic control. Renal mRNA and/or protein levels of TNFR2, but not TNF-α and TNFR1, in ETN-treated KK-Ay mice were significantly decreased compared with untreated KK-Ay mice. mRNA levels of ICAM-1, VCAM-1, and monocyte chemoattractant protein-1 and the number of F4/80-positive cells were all decreased after treatment. Numbers of cleaved caspase-3- and TUNEL-positive cells in untreated mice were very few and were not different from ETN-treated mice. In vitro, stimulation with TNF-α or HG markedly increased both mRNA levels of TNFRs, unlike in the in vivo case. Furthermore, ETN partly recovered TNF-α-induced but not HG-induced TNFR mRNA levels. In conclusion, it appears that ETN may improve the progression of the early stage of DN predominantly through inhibition of the anti-inflammatory action of the TNF-α-TNFR2 pathway.

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