14-3-3ζ suppresses RANKL signaling by destabilizing TRAF6.

Macrophages are essential regulators of inflammation and bone loss. Receptor activator of nuclear factor-κß ligand (RANKL), a pro-inflammatory cytokine, is responsible for macrophage differentiation to osteoclasts and bone loss. We recently showed that 14-3-3ζ-knockout (YwhazKO) rats exhibit increased bone loss in the inflammatory arthritis model. 14-3-3ζ is a cytosolic adaptor protein that actively participates in many signaling transductions. However, the role of 14-3-3ζ in RANKL signaling or bone remodeling is unknown. We investigated how 14-3-3ζ affects osteoclast activity by evaluating its role in RANKL signaling. We utilized 14-3-3ζ-deficient primary bone marrow-derived macrophages obtained from wildtype and YwhazKO animals and RAW264.7 cells generated using CRISPR-Cas9. Our results showed that 14-3-3ζ-deficient macrophages, upon RANKL stimulation, have bigger and stronger tartrate-resistant acid phosphatase-positive multinucleated cells and increased bone resorption activity. The presence of 14-3-3ζ suppressed RANKL-induced MAPK and AKT phosphorylation, transcription factors (NFATC1 and p65) nuclear translocation, and subsequently, gene induction (Rank, Acp5, and Ctsk). Mechanistically, 14-3-3ζ interacts with TRAF6, an essential component of the RANKL receptor complex. Upon RANKL stimulation, 14-3-3ζ-TRAF6 interaction was increased, while RANK-TRAF6 interaction was decreased. Importantly, 14-3-3ζ supported TRAF6 ubiquitination and degradation by the proteasomal pathway, thus dampening the downstream RANKL signaling. Together, we show that 14-3-3ζ regulates TRAF6 levels to suppress inflammatory RANKL signaling and osteoclast activity. To the best of our knowledge, this is the first report on 14-3-3ζ regulation of RANKL signaling and osteoclast activation.

Pediatric fibromyxoid brachial plexus tumor with YWHAZ::PLAG1 gene fusion: a case report.

Pediatric fibromyxoid soft tissue tumors may be associated with gene fusions such as YHWAZ::PLAG1, with only three reported cases in the literature. We present the fourth case, a 13-year-old male with a pediatric fibromyxoid brachial plexus tumor with YWHAZ::PLAG1 gene fusion. This is also the first case to be reported in an adolescent, in the brachial plexus, and in the Philippines. The patient presented with a 10-year history of a slowly growing left supraclavicular mass and a 1-year history of intermittent dysesthesia in the left upper extremity. Neurologic examination was unremarkable. Imaging revealed a large left supraclavicular lesion with intrathoracic extension. Surgical excision was performed, and histopathology revealed a fibromyxoid tumor with YWHAZ::PLAG1 gene fusion. Although previous examples of this gene fusion pointed toward lipoblastoma as their primary pathology, our tumor does not completely fulfill the current diagnostic criteria for a lipoblastoma and may represent an intermediate form of the disease. Our case is unique not only because it is the first reported adolescent patient harboring such a lesion but also because of the relatively lengthy natural history exhibited by the tumor prior to its resection. This provided us with valuable information about its behavior, which suggests a more indolent growth pattern. This case also highlights the clinical importance of molecular testing of tumors, where recognition of disease entities can assist clinicians in deciding and advocating for the proper management.

Wogonin inhibits hepatoma cell proliferation by targeting miR-27b-5p/YWHAZ axis.

Wogonin (5,7-dihydroxy-8-methoxyflavone), a natural flavonoid compound in herbal plants, can suppress growth in hepatocellular carcinoma (HCC). However, the microRNA (miRNA) expression profiles that are influenced by wogonin have not been thoroughly described. To explore the novel miRNAs and the biological mechanism underlying the effect of wogonin on HCC cells. The effect of wogonin on Huh7 cell growth was assessed both in vitro and in vivo. The expression profiles of miRNAs were obtained by small RNA sequencing. Luciferase reporter experiment and bioinformatics analysis were conducted to determine whether tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta (YWHAZ) can bind to miR-27b-5p. Effects of the ectopic expression of YWHAZ and miR-27b-5p on Huh7 cells proliferation and apoptosis were evaluated. Furthermore, the cell cycle, apoptosis and multiple signaling pathway-related molecules were detected by Western blot analysis. Wogonin substantially inhibited the growth of Huh7 cells both in vitro and in vivo. Seventy miRNAs exhibited greater than twofold changes in wogonin-treated cells. Upregulation of miR-27b-5p inhibited Huh7 cell proliferation, and the anticancer effect of wogonin was reversed after miR-27b-5p knockdown. miR-27b-5p directly targeted YWHAZ in HCC cells. The proliferation-inhibiting effect of miR-27b-5p was revoked by YWHAZ overexpression. Meanwhile, inhibition of HCC growth was achieved by downregulating YWHAZ. Wogonin exerted antitumor activity through multiple signaling molecules, such as focal adhesion kinase, protein kinase B, mammalian target of rapamycin and molecules related to apoptosis and cell cycle by upregulating miR-27b-5p and downregulating YWHAZ. Our findings suggest that miR-27b-5p/YWHAZ axis contributes to the inhibitory effect of wogonin in HCC by targeting related genes and multiple signaling pathways.

Circ_0035381 Regulates Acute Myeloid Leukemia Development by Modulating YWHAZ Expression via Adsorbing miR-582-3p.

Acute myeloid leukemia (AML) is a common hematopoietic disorder. Many circular RNAs (circRNAs) are abnormally expressed in AML, including hsa_circ_0035381 (circ_0035381). Nevertheless, the function and mechanism of circ_0035381 in AML remain mostly unclear. Expression of circ_0035381 was determined by qRT-PCR. The impacts of circ_0035381 on AML cell proliferation, apoptosis, and mitochondrial damage were validated via performing loss-of-function experiments. Targeting relationship was predicted by bioinformatics analysis and verified via dual-luciferase reporter and RNA immunoprecipitation assays. Circ_0035381 was upregulated in AML bone marrow samples and cells. Circ_0035381 downregulation decreased AML cell growth in nude mice and restrained AML cell proliferation and contributed to AML apoptosis and mitochondrial damage in vitro. Circ_0035381 acted as a miR-582-3p sponge, and miR-582-3p downregulation mitigated the impacts of circ_0035381 interference on AML cell proliferation, apoptosis, and mitochondrial damage. MiR-582-3p targeted Tyrosine3-monooxygenase/tryptophan5-monooxygenase activation protein zeta (YWHAZ), and it restrained AML cell proliferation and facilitated AML cell apoptosis and mitochondrial damage by decreasing YWHAZ expression. Notably, circ_0035381 regulated YWHAZ expression via miR-582-3p. Circ_0035381 knockdown repressed cell proliferation and promoted cell apoptosis and mitochondrial damage via regulating the miR-582-3p/YWHAZ axis in AML.

Evidence and Metabolic Implications for a New Non-Canonical Role of Cu-Zn Superoxide Dismutase.

Copper-zinc superoxide dismutase 1 (SOD1) has long been recognized as a major redox enzyme in scavenging superoxide radicals. However, there is little information on its non-canonical role and metabolic implications. Using a protein complementation assay (PCA) and pull-down assay, we revealed novel protein-protein interactions (PPIs) between SOD1 and tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta (YWHAZ) or epsilon (YWHAE) in this research. Through site-directed mutagenesis of SOD1, we studied the binding conditions of the two PPIs. Forming the SOD1 and YWHAE or YWHAZ protein complex enhanced enzyme activity of purified SOD1 in vitro by 40% (p < 0.05) and protein stability of over-expressed intracellular YWHAE (18%, p < 0.01) and YWHAZ (14%, p < 0.05). Functionally, these PPIs were associated with lipolysis, cell growth, and cell survival in HEK293T or HepG2 cells. In conclusion, our findings reveal two new PPIs between SOD1 and YWHAE or YWHAZ and their structural dependences, responses to redox status, mutual impacts on the enzyme function and protein degradation, and metabolic implications. Overall, our finding revealed a new unorthodox role of SOD1 and will provide novel perspectives and insights for diagnosing and treating diseases related to the protein.

FOXD1-AS1 promotes malignant behaviours of prostate cancer cells via the miR-3167/YWHAZ axis.

Herein, the effect of long noncoding RNA forkhead box D1 antisense RNA 1 (FOXD1-AS1) on malignant phenotypes of prostate cancer (PCa) cells was investigated. FOXD1-AS1 presented high expression in PCa cells according to the results of RT-qPCR. As shown by cell counting kit-8 assays, colony formation assays, wound-healing assays, Transwell assays and flow cytometry analyses, silenced FOXD1-AS1 suppressed PCa cell viability, proliferation, migration and invasion and enhanced cell apoptosis. Additionally, FOXD1-AS1 was primarily localised in cytoplasm of PCa cells. RNA immunoprecipitation assays and luciferase reporter assays revealed that FOXD1-AS1 interacted with miR-3167 in PCa cells. MiR-3167 functioned as an anti-oncogene in PCa and miR-3167 overexpression suppressed cell proliferation while promoted cell apoptosis. Moreover, the downstream target of miR-3167 is mRNA YWHAZ. FOXD1-AS1 elevated the expression of YWHAZ by binding with miR-3167. The suppressive effect of miR-3167 on YWHAZ expression was reversed by FOXD1-AS1 overexpression. Furthermore, overexpressed YWHAZ reversed the suppressive effect of FOXD1-AS1 deficiency on malignant behaviours of PCa cells. Overall, FOXD1-AS1 facilitates malignant phenotypes of PCa cells by up-regulating YWHAZ via miR-3167. The study first reveals the molecular mechanism of FOXD1-AS1 in PCa, suggesting that FOXD1-AS1 and its downstream molecules might be prognostic biomarkers before medical treatment.

Pediatric fibromyxoid soft tissue tumor with PLAG1 fusion: A novel entity?

The classification of undifferentiated soft tissue tumors continues to evolve with the expanded application of molecular analysis in clinical practice. We report three cases of a unique soft tissue tumor in young children (5 months to 2 years old) displaying a purely fibromyxoid histology, with positive staining for desmin and CD34. In two cases, RNA sequencing detected a YWHAZ-PLAG1 gene fusion, while in the third case, a previously unreported EEF1A1-PLAG1 fusion was identified. PLAG1 fusions have been reported in several pathologic entities including pleomorphic adenoma, myoepithelial tumors of skin and soft tissue, and lipoblastoma, the latter occurring preferentially in young children. In these tumors, expression of a full length PLAG1 protein comes under the control of the constitutively active promoter of the partner gene in the fusion, and the current cases conform to that model. Overexpression of PLAG1 was confirmed by diffusely positive immunostaining for PLAG1 in all three cases. Our findings raise the possibility of a novel fibromyxoid neoplasm in childhood associated with these rare PLAG1 fusion variants. The only other report of a PLAG1-YWHAZ fusion occurred in a pediatric tumor diagnosed as a "fibroblastic lipoblastoma." This finding raises the possibility of a relationship with our three cases, even though our cases lacked any fat component. Further studies with regard to a shared pathogenesis are required.

Circular RNA Paired-Related Homeobox 1 Promotes Gastric Carcinoma Cell Progression via Regulating MicroRNA-665/YWHAZ Axis.

BACKGROUND: Gastric carcinoma (GC) is a ubiquitous malignant tumor worldwide. Circular RNA paired-related homeobox 1 (circ-PRRX1), one kind of non-coding RNAs, has been reported to act as a promoter in tumor growth. This study aims to explore the effects of circ-PRRX1 on proliferation, apoptosis, and metastasis in GC and the underlying regulatory mechanisms. METHODS: The expression of circ-PRRX1, miR-665, and tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta (YWHAZ) mRNA was analyzed by quantitative real-time polymerase chain reaction (qRT-PCR). Western blot was used to analyze YWHAZ protein expression. 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-Htetrazolium bromide (MTT), flow cytometry, and transwell assay were carried out to assess the viability, apoptosis, migration, and invasion in GC cells. The interaction between miR-665 and circ-PRRX1 or YWHAZ was predicted by StarBase v2.0 and identified by dual-luciferase reporter system. Xenograft mouse model was employed to determine the effects of circ-PRRX1 knockdown on GC growth in vivo. RESULTS: Compared with normal tissues and cells, circ-PRRX1 and YWHAZ levels were upregulated, and miR-665 was downregulated in GC tissues and cells. Functionally, circ-PRRX1 knockdown inhibited the viability, migration, and invasion and promoted apoptosis in GC cells, whereas anti-miR-665 abolished these effects. Mechanistically, circ-PRRX1 was confirmed as a sponge of miR-665 to regulate YWHAZ expression. Xenograft mouse model suggested that circ-PRRX1 knockdown reduced GC cells growth in vivo. CONCLUSION: Circ-PRRX1 knockdown suppressed GC development by targeting miR-665 to inhibit YWHAZ expression, and the potential molecular mechanism may provide a theoretical basis for GC therapy.

Analysis of deep sequencing exosome-microRNA expression profile derived from CP-II reveals potential role of gga-miRNA-451 in inflammation.

Mycoplasma gallisepticum (MG) can cause chronic respiratory disease (CRD) in chickens. While several studies have reported the inflammatory functions of microRNAs during MG infection, the mechanism by which exosomal miRNAs regulate MG-induced inflammation remains to be elucidated. The expression of exosome-microRNA derived from MG-infected chicken type II pneumocytes (CP-II) was screened, and the target genes and function of differentially expressed miRNAs (DEGs) were predicted. To verify the role of exosomal gga-miR-451, Western blot, ELISA and RT-qPCR were used in this study. The results showed that a total of 722 miRNAs were identified from the two exosomal small RNA (sRNA) libraries, and 30 miRNAs (9 up-regulated and 21 down-regulated) were significantly differentially expressed. The target miRNAs were significantly enriched in the treatment group, such as cell cycle, Toll-like receptor signalling pathway and MAPK signalling pathway. The results have also confirmed that gga-miR-451-absent exosomes derived from MG-infected CP-II cells increased inflammatory cytokine production in chicken fibroblast cells (DF-1), and wild-type CP-II cell-derived exosomes displayed protective effects. Collectively, our work suggests that exosomes from MG-infected CP-II cells alter the dynamics of the DF-1 cells, and may contribute to pathology of the MG infection via exosomal gga-miR-451 targeting YWHAZ involving in inflammation.

YWHAZ amplification/overexpression defines aggressive bladder cancer and contributes to chemo-/radio-resistance by suppressing caspase-mediated apoptosis.

The objective of this study was to characterize the oncogenic actions of a recently identified cancer-associated gene YWHAZ (also named as 14-3-3 ζ/δ) in urothelial carcinomas of the urinary bladder (UCUB). A genome-wide study revealed YWHAZ to be involved in the amplicon at 8q22.3, and its genetic amplification was detected predominantly in muscle-invasive bladder cancer (MIBC). Immunohistochemical staining confirmed the association of YWHAZ overexpression with higher tumor stages, lymph node/vascular invasion, and mitotic activity. Univariate and multivariate analyses further indicated the prognostic potential of YWHAZ for more aggressive cancer types. Both gene set enrichment analysis and STRING network studies suggested involvement of YWHAZ in regulating caspase-mediated apoptosis. Ectopic expression of YWHAZ in bladder cells with low endogenous YWHAZ levels boosted cell resistance to doxorubicin and cisplatin, as well as to ionizing radiation. Conversely, YWHAZ-knockdown using specific shRNA in cells with high endogenous YWHAZ levels diminished survival activity, suppressing cell growth and increasing cell death. Our findings confirm the essential role played by YWHAZ in sustaining cell proliferation during chemo/radiotherapy. Treatments based on anti-YWHAZ strategies may thus be beneficial for UCUB patients overexpressing YWHAZ. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

MicroRNA-451 inhibits vascular smooth muscle cell migration and intimal hyperplasia after vascular injury via Ywhaz/p38 MAPK pathway.

Increasing evidence has indicated that intimal hyperplasia is a common event in the pathophysiology of many vascular diseases including atherosclerosis (AS). Recently, deregulated microRNAs (miRNAs) have been reported to be associated with the pathophysiology of AS. However, the biological function and regulatory mechanisms of miRNAs in intimal hyperplasia in AS remain largely unclear. The aim of this study was to investigate the effects of miRNAs on intimal hyperplasia and reveal the underlying mechanisms of their effects. Firstly, the model of rat vascular injury was successfully constructed in vivo. Then, the miRNAs expression profiles were analyzed by miRNA microarray. It was observed that miR-451 was significantly downregulated in injury carotid arteries. Subsequently, we investigated miR-451 function and found that upregulation of miR-451 by agomir-451 improves intimal thickening in rats following vascular injury. It was also observed that miR-451 was downregulated in the VSMCs following platelet-derived growth factor type BB (PDGF-BB) stimulation. The upregulation of miR-451 attenuated PDGF-BB-induced VSMCs injury, as evidenced by inhibition of proliferation, invasion and migration. Besides, overexpression of miR-451 blocked the activation of p38 MAPK signaling pathway in PDGF-BB treated VSMCs, as demonstrated by the downregulation of phosphorylated (p-) p38. In addition, Ywhaz, a positive regulator of p38 MAPK signaling pathway, was found to be a direct target of miR-451 in the VSMCs and this was validated using a luciferase reporter assay. Overexpression of Ywhaz partially abolished the inhibitory effects of miR-451 overexpression on PDGF-BB induced VSMCs injury. Collectively, these findings indicated that miR-451 protected intimal hyperplasia and PDGF-BB-induced VSMCs injury by Ywhaz/p38 MAPK pathway, and miR-451 may be considered as a potential therapeutic target in the treatment of AS.

Long noncoding RNA H19 acts as a miR-340-3p sponge to promote epithelial-mesenchymal transition by regulating YWHAZ expression in paclitaxel-resistant breast cancer cells.

Breast cancer (BC) is the leading cause of cancer-related death in women worldwide and one of the most prevalent malignancy. In recent years, increasing evidence had illuminated that long noncoding RNAs (lncRNAs) serve as critical factors in multiple tumor progression, including BC. Emerging references had indicated that the lncRNA H19 acts as significant roles in tumor progression and epithelial-mesenchymal transition (EMT). However, the underlying molecular mechanisms and biological roles of H19 in BC invasion, metastasis and EMT are still unclear. In this study, it was detected that the expression level of H19 was increased in BC paclitaxel-resistant (PR) cells subline (MCF-7/PR) in comparison with MCF-7 parental cells. In vitro, there were demonstrated that H19 overexpression promoted BC cells proliferation, metastasis, invasion and EMT procedures, and suppressed cells apoptosis. Whereas, H19 suppression resulted in the contrary biological effects. Besides, bioinformatics tools and dual-luciferase reporters assays indicated that miR-340-3p could act as a potential target gene of H19, the underlying mechanism studies proved that H19 could act as a competing endogenous RNA (ceRNA) via competitively binding miR-340-3p to promote BC cell proliferation, metastasis and EMT by regulating tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta (YWHAZ) and potentiate the Wnt/ß-catenin signaling in BC cells. In summary, our findings demonstrated that H19 could act as a ceRNA in BC progression, metastasis and EMT through modulating miR-340-3p/YWHAZ axis and activating the canonical Wnt/ß-catenin signaling pathway, indicating that H19 might act as an underlying therapeutic target and prognostic biomarker for BC therapy.

The clinical and prognostic significance of YWHAZ in non-small-cell lung cancer patients: Immunohistochemical analysis.

YWHAZ has been suggested to as an oncogene in various human malignancies, including non-small-cell lung cancer (NSCLC). Our study presents more evidence to confirm the clinical significance and biological function of YWHAZ in NSCLC. In our results, YWHAZ was upregulated in lung squamous cell carcinoma tissues and lung adenocarcinoma tissues through analyzing The Cancer Genome Atlas (TCGA) database, and confirmed high levels of YWHAZ messenger RNA and protein in lung squamous cell carcinoma tissues and lung adenocarcinoma tissues through quantitative real-time polymerase chain reaction and immunohistochemistry. Moreover, YWHAZ overexpression was correlated with advanced clinical stage, more lymph node metastasis and present distant metastasis in NSCLC patients. Survival analysis indicated that high level of YWHAZ protein expression was associated with short overall survival time in NSCLC patients, and YWHAZ expression was independent prognostic factors for overall survival in NSCLC patients. Moreover, Silencing of YWHAZ expression represses NSCLC cell migration and invasion. In conclusion, YWHAZ is a credible prognostic biomarker, and may be a therapeutic target in NSCLC.

miR-375-3p/YWHAZ/ß-catenin axis regulates migration, invasion, EMT in gastric cancer cells.

YWHAZ (14-3-3ζ) plays crucial roles in regulating proliferation, apoptosis, migration, and invasion of gastric cancer (GC) cells. However, its extensive roles and potential mechanisms in GC cells remain unknown, and need to be researched deeply. In this study, we focus on the role of miR-375/YWHAZ axis in migration, invasion and epithelial-to-mesenchymal transition (EMT) of GC cells. YWHAZ level was assessed by western blot and qPCR assays in GC cells. Scratch and transwell assays were used to determine the migration and invasion of GC cells. The protein levels of correlative molecules were detected by western blot. The regulation of miR-375 on the expression of its target gene YWHAZ was verified by dual-luciferase report system. According to the results, knockdown of YWHAZ inhibited the migration, invasion and EMT of GC cells. Moreover, silencing of YWHAZ restrained the activation of wnt/ß-catenin signalling pathway. YWHAZ was confirmed to be a target gene of miR-375, and its expression was regulated by miR-375 in GC cells. Transfection of miR-375 inhibitor promoted the migration, invasion, EMT and activation of wnt/ß-catenin pathway in GC cells, which was suppressed by inhibition of YWHAZ. Taken together, this study suggests that miR-375/YWHAZ axis may be served as a novel therapeutic target for GC patients.

Transcriptional Regulation of gga-miR-451 by AhR:Arnt in Mycoplasma gallisepticum (HS Strain) Infection.

MicroRNAs (miRNAs) have been determined to be important regulators for pathogenic microorganism infection. However, it is largely unclear how miRNAs are triggered during pathogen infection. We previously reported that the up-regulation of gga-miR-451 negatively regulates the Mycoplasma gallisepticum (MG)-induced production of inflammatory cytokines via targeting tyrosine3-monooxygenase/tryptophan5-monooxygenase activation protein zeta (YWHAZ). The aim of this study was to investigate the mechanism regulating gga-miR-451 in MG infection in chickens. Analysis of gga-miR-451 precursor, pri-miR-451, and pre-miR-451 indicated that the regulation occurred transcriptionally. We also identified the transcriptional regulatory region of gga-miR-451 that contained consensus-binding motif for aryl hydrocarbon receptor (AhR) and aryl hydrocarbon receptor nuclear translocator (Arnt) complex, which is known as the transcription factor that regulates gene expression. Luciferase reporter assays combined with chromatin immunoprecipitation (ChIP) demonstrated that AhR:Arnt bound directly to the promoter elements of gga-miR-451, which were responsible for gga-miR-451 transcription in the context of MG infection. Furthermore, upregulation of AhR:Arnt significantly induced gga-miR-451 and inhibited YWHAZ expression, suggesting that AhR:Arnt may play an anti-inflammatory role in MG infection. This discovery suggests that induced gga-miR-451 expression is modulated by AhR:Arnt in response to MG infection.

Structure-based assessment and network analysis of targeting 14-3-3 proteins in prostate cancer.

Developing combination therapy for castrate-resistant prostate cancer (CRPC) may require exploiting new drug targets outside androgen receptor and PI3K / AKT / mTOR signal transduction pathways implicated in prostate cancer (PCa) progression. One such possible new target is YWHAZ of the 14-3-3 protein family as this gene has prognostic significance for metastatic CRPC patients. However, there are no small molecules targeting YWHAZ commercially available. Hence, we explored whether the small molecule BV02 targeting another 14-3-3 protein family member SFN also binds to YWHAZ. Using advanced docking algorithms we find that BV02 docks many other 14-3-3 family members. In addition, the amphipathic groove where drug binding occurs also has a high binding affinity for other drugs used to treat PCa such as docetaxel. The proteome of metastatic PCa models (LNCaP clone FGC and PC-3) was perturbed as a result of BV02 treatment. Through data integration of three proteomics data sets we found that BV02 modulates numerous protein-protein interactions involving 14-3-3 proteins in our PCa models.

Inhibition of Tyrosine 3-Monooxygenase/Tryptophan 5-Monooxygenase Activation Protein Zeta (YWHAZ) Overcomes Drug Resistance and Tumorigenicity in Ovarian Cancer.

BACKGROUND/AIMS: Cancer stem-like cells are the main cause of tumor occurrence, progression, and therapeutic resistance. However, the precise signals required for the maintenance of the stem-like traits of these cells in ovarian cancer remain elusive. We have thus worked to elucidate the functional role of Tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta (YWHAZ), a gene encoding the 14-3-3ζ protein, in the regulation of multidrug resistance and stem cell-like traits in ovarian cancer. METHODS: We detected the YWHAZ levels in human ovarian cancer specimens and cell lines using quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and western blots. MTS assays, soft agar colony formation assays, migration assays, cell cycle analysis, sphere formation assays, and flow cytometry were applied to investigate the functional role of YWHAZ in ovarian cancer. RESULTS: Our data reveals substantially increased YWHAZ expression in both cisplatin- and paclitaxel-resistant ovarian cancer cells. Silencing YWHAZ restored the sensitivity of resistant ovarian cancer cells to cisplatin and paclitaxel. Furthermore, in vitro studies showed that down-regulation of YWHAZ inhibited cell cycle progression, migration, and the expression of stem cell markers. Moreover, tumorigenicity was suppressed in tumor-bearing BALB/c nude mice following YWHAZ knockdown. Additionally, we demonstrated that the expression of YWHAZ was directly down-regulated by miR-30e in resistant ovarian cancer cells. CONCLUSION: Our results have led to new insights into the essential role of YWHAZ in the regulation of tumourigenesis, stem-like traits, and drug resistance in ovarian cancer, thereby helping to identify a potential target for ovarian cancer therapy.

Analysis of 14-3-3 isoforms expressed in photoreceptors.

The 14-3-3 family of proteins has undergone considerable expansion in higher eukaryotes with humans and mice expressing seven isoforms (ß, ε, η, γ, θ, ζ, and σ) from seven distinct genes (YWHAB, YWAHE, YWHAH, YWHAG, YWHAQ, YWHAZ, and SFN). Growing evidence indicates that while highly conserved, these isoforms are not entirely functionally redundant as they exhibit unique tissue expression profiles, subcellular localization, and biochemical functions. A key limitation in our understanding of 14-3-3 biology lies in our limited knowledge of cell-type specific 14-3-3 expression. Here we provide a characterization of 14-3-3 expression in whole retina and isolated rod photoreceptors using reverse-transcriptase digital droplet PCR. We find that all 14-3-3 genes with the exception of SFN are expressed in mouse retina with YWHAQ and YWHAE being the most highly expressed. Rod photoreceptors are enriched in YWHAE (14-3-3 ε). Immunohistochemistry revealed that 14-3-3 ε and 14-3-3 ζ exhibit unique distributions in photoreceptors with 14-3-3 ε restricted to the inner segment and 14-3-3 ζ localized to the outer segment. Our data demonstrates that, in the retina, 14-3-3 isoforms likely serve specific functions as they exhibit unique expression levels and cell-type specificity. As such, future investigations into 14-3-3 function in rod photoreceptors should be centered on 14-3-3 ε and 14-3-3 ζ, depending on the subcellular region of question.

YWHAZ Binds to TRIM21 but Is Not Involved in TRIM21-stimulated Osteosarcoma Cell Proliferation.

OBJECTIVE: Osteosarcoma is the most common type of malignant bone tumor in children and adolescents. The role of E3 ligases in tumorigenesis is currently a focus in tumor research. In the present study, we investigated the role of the E3 ligase tripartite motif 21 (TRIM21) in osteosarcoma cell proliferation. METHODS: 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assays were used to assess osteosarcoma cell viability. U2-OS cells stably carrying a recombinant lentivirus expressing tetracycline-regulated TRIM21 were screened. Co-immunoprecipitation was coupled with LCMS/MS analysis to identify novel interacting partners of TRIM21. Co-immunoprecipitation and bimolecular fluorescence complementation (BIFC) were performed to validate the interactions between TRIM21 and its novel partner YWHAZ. A TRIM21-ΔRING construct was generated to test the effects of TRIM21 ligase activity on YWHAZ. RESULTS: TRIM21 positively regulated osteosarcoma cell proliferation. Overexpression of TRIM21 enhanced osteosarcoma cell tolerance toward various stresses. YWHAZ protein was identified as a novel interacting partner of TRIM21 and its expression levels were negatively regulated by TRIM21. The RING domain of TRIM21 was required for TRIM21 negative regulation of YWHAZ expression. However, overexpression of YWHAZ did not affect positive regulation of osteosarcoma cell proliferation by TRIM21. CONCLUSION: Our results further clarify the molecular mechanisms underlying the pathogenesis of osteosarcoma.

gga-miR-451 Negatively Regulates Mycoplasma gallisepticum (HS Strain)-Induced Inflammatory Cytokine Production via Targeting YWHAZ.

Mycoplasma gallisepticum (MG) is the most economically significant mycoplasma pathogen of poultry that causes chronic respiratory disease (CRD) in chickens. Although miRNAs have been identified as a major regulator effect on inflammatory response, it is largely unclear how they regulate MG-induced inflammation. The aim of this study was to investigate the functional roles of gga-miR-451 and identify downstream targets regulated by gga-miR-451 in MG infection of chicken. We found that the expression of gga-miR-451 was significantly up-regulated during MG infection of chicken embryo fibroblast cells (DF-1) and chicken embryonic lungs. Overexpression of gga-miR-451 decreased the MG-induced inflammatory cytokine production, including tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), and interleukin-6 (IL-6), whereas inhibition of gga-miR-451 had the opposite effect. Gene expression data combined with luciferase reporter assays demonstrated that tyrosine3-monooxygenase/tryptophan5-monooxygenase activation protein zeta (YWHAZ) was identified as a direct target of gga-miR-451 in the context of MG infection. Furthermore, upregulation of gga-miR-451 significantly inhibited the MG-infected DF-1 cells proliferation, induced cell-cycle arrest, and promoted apoptosis. Collectively, our results demonstrate that gga-miR-451 negatively regulates the MG-induced production of inflammatory cytokines via targeting YWHAZ, inhibits the cell cycle progression and cell proliferation, and promotes cell apoptosis. This study provides a better understanding of the molecular mechanisms of MG infection.