Dual-specificity Phosphatase Research Articles

DUSP2 Deletion Inhibits Macrophage Migration by Inhibiting ERK Activation in Zebrafish

Dual-specificity phosphatase 2 (DUSP2) regulates the activation of members of the mitogen-activated protein kinase (MAPK) family, which is involved in a variety of cellular processes including cell proliferation, differentiation, apoptosis, and migration. DUSP2 also regulates the expression of inflammatory mediators in macrophages; however, it remains unknown whether DUSP2 participates in macrophage migration. Here, using the tail fin injury model in zebrafish larvae, we found that the deletion of DUSP2 inhibited the expression of pro-inflammatory cytokines and macrophage chemokines. Moreover, live imaging results showed that the migration of macrophages to the injury site was inhibited after DUSP2 deletion. This inhibitory effect was mediated through the reduced activation of extracellular regulated protein kinases (ERK) in DUSP2 knockout zebrafish.

Screening of novel biomarkers for breast cancer based on WGCNA and multiple machine learning algorithms.

Breast cancer (BC) ranks first in incidence among women, with approximately 2 million new cases per year. Therefore, it is essential to investigate emerging targets for BC patients' diagnosis and prognosis. We analyzed gene expression data from 99 normal and 1,081 BC tissues in The Cancer Genome Atlas (TCGA) database. Differentially expressed genes (DEGs) were identified using "limma" R package, and relevant modules were chosen through Weighted Gene Coexpression Network Analysis (WGCNA). Intersection genes were obtained by matching DEGs to WGCNA module genes. Functional enrichment studies were performed on these genes using Gene Ontology (GO), Disease Ontology (DO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Biomarkers were screened via Protein-Protein Interaction (PPI) networks and multiple machine-learning algorithms. The Gene Expression Profiling Interactive Analysis (GEPIA), The University of ALabama at Birmingham CANcer (UALCAN), and Human Protein Atlas (HPA) databases were employed to examine mRNA and protein expression of eight biomarkers. Kaplan-Meier mapper tool assessed their prognostic capabilities. Key biomarkers were analyzed via single-cell sequencing, and their relationship with immune infiltration was examined using Tumor Immune Estimation Resource (TIMER) database and "xCell" R package. Lastly, drug prediction was conducted based on the identified biomarkers. We identified 1,673 DEGs and 542 important genes through differential analysis and WGCNA, respectively. Intersection analysis revealed 76 genes, which play significant roles in immune-related viral infection and IL-17 signaling pathways. DIX domain containing 1 (DIXDC1), Dual specificity phosphatase 6 (DUSP6), Pyruvate dehydrogenase kinase 4 (PDK4), C-X-C motif chemokine ligand 12 (CXCL12), Interferon regulatory factor 7 (IRF7), Integrin subunit alpha 7 (ITGA7), NIMA related kinase 2 (NEK2), and Nuclear receptor subfamily 3 group C member 1 (NR3C1) were selected as BC biomarkers using machine-learning algorithms. NEK2 was the most critical gene for diagnosis. Prospective drugs targeting NEK2 include etoposide and lukasunone. Our study identified DIXDC1, DUSP6, PDK4, CXCL12, IRF7, ITGA7, NEK2, and NR3C1 as potential diagnostic biomarkers for BC, with NEK2 having the highest potential to aid in diagnosis and prognosis in clinical settings.

Norepinephrine as the Intrinsic Contributor to Contact Lens-Induced Pseudomonas aeruginosa Keratitis.

Contact lens wear (CLW) is one of the leading risk factors for Pseudomonas aeruginosa keratitis (PAK). However, the intrinsic factors that contribute to the high susceptibility to keratitis during CLW remain to be elucidated. CLW over an extended period can elevate corneal norepinephrine (NE) concentration. In this study, we investigated the role of NE in promoting PAK. We constructed an injury-induced PAK model and a CLW-induced PAK model to confirm the impact of NE during corneal infection. Pharmacological blockage of NE and gene knockdown mouse were used to investigate the downstream effector of NE. RNA sequencing was performed to explore the cellular alterations during NE treatment. Non-parametric Mann-Whitney U test or Kruskal-Wallis test were used to ascertain the significance (P < 0.05). Supplementation of NE led to PAK even without artificial corneal injury during CLW. The effect was mediated by the β2-adrenergic receptor (β2-AR) in the corneal epithelium. The β2-AR blockage by the NE antagonist ICI118,551 (ICI) or by deleting of its encoding gene Adrb2 significantly alleviated infection during CLW. Conversely, β2-AR activation compromised the integrity of the epithelium and significantly increased the cortical plaque marker ezrin. Transcriptome analysis identified that the protective effect of ICI on the keratitis was mediated by dual-specificity phosphatases. Suramin, a Dusp5 antagonist, abrogated the protective effect of ICI. These data reveal a new mechanism by which NE acts as an intrinsic factor that promotes CLW-induced PAK and provide novel therapeutic targets for treating keratitis by targeting NE-β2-AR.

Liver transcriptomic and methylomic analyses identify transcriptional mitogen-activated protein kinase regulation in facultative hibernation of Syrian hamster.

Hibernation consists of alternating torpor-arousal phases, during which animals cope with repetitive hypothermia and ischaemia-reperfusion. Due to limited transcriptomic and methylomic information for facultative hibernators, we here conducted RNA and whole-genome bisulfide sequencing in liver of hibernating Syrian hamster (Mesocricetus auratus). Gene ontology analysis was performed on 844 differentially expressed genes and confirmed the shift in metabolic fuel utilization, inhibition of RNA transcription and cell cycle regulation as found in seasonal hibernators. Additionally, we showed a so far unreported suppression of mitogen-activated protein kinase (MAPK) and protein phosphatase 1 pathways during torpor. Notably, hibernating hamsters showed upregulation of MAPK inhibitors (dual-specificity phosphatases and sproutys) and reduced levels of MAPK-induced transcription factors (TFs). Promoter methylation was found to modulate the expression of genes targeted by these TFs. In conclusion, we document gene regulation between hibernation phases, which may aid the identification of pathways and targets to prevent organ damage in transplantation or ischaemia-reperfusion.

Pseudophosphatase STYXL1 depletion enhances glucocerebrosidase trafficking to lysosomes via ER stress.

Pseudophosphatases are catalytically inactive but share sequence and structural similarities with classical phosphatases. STYXL1 is a pseudophosphatase that belongs to the family of dual-specificity phosphatases and is known to regulate stress granule formation, neurite formation and apoptosis in different cell types. However, the role of STYXL1 in regulating cellular trafficking or the lysosome function has not been elucidated. Here, we show that the knockdown of STYXL1 enhances the trafficking of β-glucocerebrosidase (β-GC) and its lysosomal activity in HeLa cells. Importantly, the STYXL1-depleted cells display enhanced distribution of endoplasmic reticulum (ER), late endosome and lysosome compartments. Further, knockdown of STYXL1 causes the nuclear translocation of unfolded protein response (UPR) and lysosomal biogenesis transcription factors. However, the upregulated β-GC activity in the lysosomes is independent of TFEB/TFE3 nuclear localization in STYXL1 knockdown cells. The treatment of STYXL1 knockdown cells with 4-PBA (ER stress attenuator) significantly reduces the β-GC activity equivalent to control cells but not additive with thapsigargin, an ER stress activator. Additionally, STYXL1-depleted cells show the enhanced contact of lysosomes with ER, possibly via increased UPR. The depletion of STYXL1 in human primary fibroblasts derived from Gaucher patients showed moderately enhanced lysosomal enzyme activity. Overall, these studies illustrated the unique role of pseudophosphatase STYXL1 in modulating the lysosome function both in normal and lysosome-storage disorder cell types. Thus, designing small molecules against STYXL1 possibly can restore the lysosome activity by enhancing ER stress in Gaucher disease.

Mmu-miR-25-3p promotes macrophage autophagy by targeting DUSP10 to reduce mycobacteria survival.

The present study aimed to investigate the regulation of miR-25-3p on macrophage autophagy and its effect on macrophage clearance of intracellular Mycobacterium bovis Bacillus Calmette-Guerin (BCG) retention based on the previous findings on the differential expression of exosomal miRNA in macrophages infected with BCG. Through enrichment analysis and Hub gene analysis, key differentially expressed miRNA and its target genes were selected. The targeted binding ability of the screened mmu-miR-25-3p and its predicted target gene DUSP10 was determined through the TargetScan database, and this was further verified by dual luciferase reporter gene assay. mmu-miR-25-3p mimics, mmu-miR-25-3p inhibitor, si-DUSP10, miR-NC,si-NC and PD98059 (ERK Inhibitor) were used to intervene macrophages Raw264.7. Rt-qPCR was used to detect the expression levels of mmu-miR-25-3p and DUSP10 mRNA. Western blot was used to detect the expression levels of DUSP10, LC3-II, p-ERK1/2, beclin1, Atg5 and Atg7. The autophagy flux of macrophage Raw264.7 in each group was observed by confocal laser microscopy, and the expression distribution of DUSP10 and the structure of autophagosomes were observed by transmission electron microscopy. Finally, the intracellular BCG load of macrophage Raw264.7 was evaluated by colony-forming unit (CFU) assay. Bioinformatics analysis filtered and identified the differentially expressed exosomal miRNAs. As a result, mmu-miR-25-3p expression was significantly increased, and dual specificity phosphatase 10 (DUSP10) was predicted as its target gene that was predominantly involved in autophagy regulation. The dual luciferase reporter gene activity assay showed that mmu-miR-25-3p was targeted to the 3'-untranslated region (UTR) of DUSP10. The infection of BCG induced the upregulation of mmu-miR-25-3p and downregulation of DUSP10 in RAW264.7 cells, which further increased the expression of LC3-II and promoted autophagy. Upregulated mmu-miR-25-3p expression decreased the level of DUSP10 and enhanced the phosphorylation of ERK1/2, which in turn upregulated the expression of LC3-II, Atg5, Atg7, and Beclin1. Immuno-electron microscopy, transmission electron microscopy, and autophagic flux analysis further confirmed that the upregulation of mmu-miR-25-3p promotes the autophagy of macrophages after BCG infection. The CFU number indicated that upregulated mmu-miR-25-3p expression decreased the mycobacterial load and accelerated residual mycobacteria clearance. mmu-miR-25-3p promotes the phosphorylation of ERK1/2 by inhibiting the expression of DUSP10, thus enhancing the BCG-induced autophagy of macrophages. These phenomena reduce the bacterial load of intracellular Mycobacterium and facilitate the clearance of residual mycobacteria. mmu-miR-25-3p has great potential as a target for anti-tuberculosis immunotherapy and can be the optimal miRNA loaded into exosomal drug delivery system in future studies.

DUSP10 alleviates ischemic stroke-induced neuronal damage by restricting p38/JNK pathway

Neuronal apoptosis is considered one of the hallmarks of ischemic stroke. Dual specificity phosphatase 10 (DUSP10), a member of the dual-specificity phosphatase family, which is involved in the regulation of apoptosis process. This study aimed to investigate the effect of on apoptosis in primary cortical neurons exposed to oxygen-glucose deprivation and reoxygenation (OGD/R) and mice suffered from transient middle cerebral artery occlusion and reperfusion (MCAO/R). The results showed that DUSP10 overexpression improved survival and reduced apoptosis in neurons subjected to OGD/R, which was manifested by decreased apoptotic proteins (cleaved caspase 3 and bax) and TUNEL+ cells, as well as increased the anti-apoptotic protein (bcl-2). DUSP10 overexpression inhibited the p38/JNK signaling pathway after OGD/R treatment, whilst DUSP10 knockdown had opposite effects. In addition, the p38 inhibitor SB203580 or JNK inhibitor SP600125 attenuated the increased apoptosis of OGD/R-stimulated neurons treated with DUSP10 silencing. Consistently, DUSP10 knockdown exacerbated infarct volume in MCAO/R injury. The data of Nissl staining and TUNEL-NeuN double staining revealed that DUSP10 interference aggravated neuronal damage in the ischemic penumbra of mice. Furthermore, DUSP10 inhibition activated the p38/JNK axis accompanied by enhanced phosphorylation of p38 and JNK in vivo. In summary, DUSP10 is a neuroprotective agent against ischemic stroke-induced neuronal damage via suppressing the p38/JNK signaling pathway.

Abstract A023: Structural basis for regulation of MAPK signaling by DUSP5 and DUSP6

Abstract The Ras/mitogen-activated protein kinase (MAPK) cascade plays an essential role in several critical cellular processes, such as cell growth and proliferation, and hyperactivation of this pathway is frequently observed in cancer. DUSP5 and DUSP6 are dual specificity phosphatases (capable of dephosphorylating phospho-tyrosines as well as phospho-serines/threonines) that act as key regulators of MAPK signaling that inactivate ERK by dephosphorylating its activation loop and sequestering ERK in an inactive state. DUSP5 and DUSP6 have been reported to function as tumor suppressors in some Ras-driven cancers, including skin cancer and pancreatic cancer, while promoting tumorigenesis in other contexts, such as thyroid cancer or glioblastoma. Despite the importance of these phosphatases in modulating ERK signaling, the structural basis for their interaction with ERK and their dual specificity remain poorly understood. It has also been reported that ERK binding allosterically activates DUSP6, but not DUSP5, and the mechanism underlying this is unclear. While structures of individual domains of these proteins have been solved, there are no structures of full-length DUSP5 or DUSP6, or of an ERK/DUSP complex. To gain insight into the molecular determinants of ERK dephosphorylation by these phosphatases, we have purified full-length DUSP5 and DUSP6, as well as the phosphatase domains of both proteins. We have also generated full-length phosphorylated ERK2 (pERK2). Through in vitro dephosphorylation assays, we have observed that full-length DUSP5 and DUSP6 dephosphorylate ERK2 much more rapidly than the isolated phosphatase domains, indicating an essential role for their N-terminal regulatory domains in this process. Using biolayer interferometry, we show that catalytically inactive mutants of full-length DUSP5 and DUSP6 bind very tightly to pERK2 with low nanomolar affinity. We have reconstituted complexes of pERK2 bound to catalytically inactive full-length DUSP5 or DUSP6, and we are pursuing structures of these complexes using x-ray crystallography and cryo-electron microscopy. These studies will improve our understanding of the regulation of ERK and its phosphatases DUSP5 and DUSP6 and shed light on the similarities and differences between these complexes. These structures could also potentially reveal the structural features underlying the dual specificity of DUSP5 and DUSP6. Citation Format: Jennifer E. Kung, Jawahar Sudhamsu. Structural basis for regulation of MAPK signaling by DUSP5 and DUSP6 [abstract]. In: Proceedings of the AACR Special Conference: Targeting RAS; 2023 Mar 5-8; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Res 2023;21(5_Suppl):Abstract nr A023.

MRNA markers associated with malignant pleural effusion

Malignant pleural effusions (MPE) commonly result from malignant tumors and represent advanced-stage cancers. Thus, in clinical practice, early recognition of MPE is valuable. However, the current diagnosis of MPE is based on pleural fluid cytology or histologic analysis of pleural biopsies with a low diagnostic rate. This research aimed to assess the diagnostic ability of eight previously identified Non-Small Cell Lung Cancer (NSCLC)-associated genes for MPE. In the study, eighty-two individuals with pleural effusion were recruited. There were thirty-three patients with MPE and forty-nine patients with benign transudate. mRNA was isolated from the pleural effusion and amplified by Quantitative real-time PCR. The logistic models were further applied to evaluate the diagnostic performance of those genes. Four significant MPE-associated genes were discovered in our study, including Dual-specificity phosphatase 6 (DUSP6), MDM2 proto-oncogene (MDM2), Ring finger protein 4 (RNF4), and WEE1 G2 Checkpoint Kinase (WEE1). Pleural effusion with higher expression levels of MDM2 and WEE1 and lower expression levels of RNF4 and DUSP6 had a higher possibility of being MPE. The four-gene model had an excellent performance distinguishing MPE and benign pleural effusion, especially for pathologically negative effusions. Therefore, the gene combination is a suitable candidate for MPE screening in patients with pleural effusion. We also identified three survival-associated genes, WEE1, Neurofibromin 1 (NF1), and DNA polymerase delta interacting protein 2 (POLDIP2), which could predict the overall survival of patients with MPE.

Abstract LB019: DUSP4 overexpression exerts anti-tumor effects in vivo in pancreatic cancer xenografts in nu/nu mice

Abstract Pancreatic cancer (PC) remains one of the most lethal of all human malignancies, being highly aggressive and difficult to treat if diagnosed at late stages. Therefore, it is important to dissect molecular mechanisms implicated in PC pathophysiology. Dual specificity phosphatase-4 (DUSP4) is a phosphatase known to negatively regulate the mitogen-activated protein (MAP) kinase family (MAPK/ERK, SAPK/JNK, P38), which are involved in multiple cancers, including PC. Previously, using tissue microarray containing a variety of pancreatic cancers and normal pancreatic tissues, we found that DUSP4 was significantly downregulated in human PC. We also demonstrated that forced overexpression of DUSP4 resulted in anti-proliferative responses in MIA PaCa-2 human PC cells (Cancer Res 2016; 76 (14_Supplement): 3667). Here, we expanded our study to determine, i) the effects of DUSP4 overexpression on tumorigenicity in vivo, and ii) the molecular mechanisms associated with DUSP4 overexpression-mediated anti-proliferative responses. MIA PaCa-2 cells were stably transfected with DUSP4 overexpression (OE) plasmid or its empty vector (pCMV6) control, followed by subcutaneous implantation into nu/nu mice (n=8 each group). Tumor growth was measured weekly for 6 weeks followed by excision of tumors and molecular analyses. We found significant reduction in tumor volume and weight in DUSP4 OE group. Further, we found marked reduction in p-ERK1/2 and p-P38 proteins in tumors from DUSP4 OE group. To determine the global mechanisms of DUSP4, we analyzed DUSP4-overexpressing MIA PaCa-2 cell lysates using quantitative global proteomics. Overall, 1678 proteins were identified with ≥2 unique peptides. Out of these, 54 proteins were significantly modulated ≥1.6-fold. Using Ingenuity Pathway Analysis (IPA), we found the association of modulated proteins with increased apoptosis and inhibited invasive and malignant tumors. The top five modulated proteins identified in response to DUSP4 OE were ADD3, PDLIM1, COL2A1, SLC20A1 and CALB2, with the first three being upregulated and the remaining two downregulated. Based on published studies in other cancers, these data support the tumor suppressor role of DUSP4 in PC since i) the loss of ADD3 and PDLIM1 (both cytoskeleton-related proteins) have been found to promote tumor growth, ii) higher expression of COL2A1 has been associated with delayed tumor recurrence, iii) higher expression of SLC20A1 (sodium-phosphate symporter) and CALB2 (calcium-binding protein) are known to be associated with cancer progression. The specific roles of these proteins in PC are not well known, providing us novel opportunities for future investigations. Overall, our data support the tumor suppressor role of DUSP4 in PC and warrants further research to validate our findings. Citation Format: Chandra K. Singh, Mary A. Ndiaye, Gagan Chhabra, Minakshi Nihal, Nihal Ahmad. DUSP4 overexpression exerts anti-tumor effects in vivo in pancreatic cancer xenografts in nu/nu mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB019.

Dual targeting of aberrant DNA and histone methylation synergistically suppresses tumor cell growth in ATL.

Adult T-cell leukemia/lymphoma (ATL) is a malignancy of mature CD4+ T cells caused by human T-cell lymphotropic virus type 1 (HTLV-1)-induced T-cell transformation. After infection with HTLV-1, it takes several decades for HTLV-1 carriers to develop ATL. The prognosis of ATL remains poor despite several new agents being approved in the last few years. Recently, it has been noted that epigenetic abnormalities, both DNA methylation and trimethylation at histone H3Lys27 (H3K27me3), contribute to ATL leukemogenesis. Here, we investigated the effect of combination treatment with DNA demethylating agents (azacitidine [AZA], decitabine (DAC), and OR-2100 (OR21), which is a silylated derivative of DAC) and inhibitors of enhancer of zeste homolog 2 (EZH2) (EPZ-6438 and DS-3201b), which catalyze trimethylation of H3K27, in ATL. The combination of DAC and OR21 but not AZA with EZH inhibitors exhibited synergistic anti-ATL effects invitro and invivo, concomitant with DNA demethylation and reduction of H3K27me3. The combination induced gene expression reprogramming. Dual-specificity phosphatase 5 (DUSP5), an extracellular signal-regulated kinase (ERK)-specific phosphatase, was identified as a key molecule that mediated the inhibitory effect of combination treatment by inactivating the ERK signaling pathway. DUSP5 was downregulated by DNA methylation and H3K27me3 accumulation in the promoter region in HTLV-1-infected cells from patients with ATL during ATL leukemogenesis. The present results demonstrate that dual targeting of aberrant DNA and histone methylation synergistically suppresses tumor cell growth by restoring DUSP5, and that dual targeting of aberrant DNA and histone methylation is a feasible therapeutic approach for ATL.

ERK2 Mutations Affect Interactions, Localization, and Dimerization.

The most frequent ERK2 (MAPK1) mutation in cancers, E322K, lies in the common docking (CD) site, which binds short motifs made up of basic and hydrophobic residues present in the activators MEK1 (MAP2K1) and MEK2 (MAP2K2), in dual specificity phosphatases (DUSPs) that inactivate the kinases, and in many of their substrates. Also, part of the CD site, but mutated less often in cancers, is the preceding aspartate (D321N). These mutants were categorized as gain of function in a sensitized melanoma system. In Drosophila developmental assays, we found that the aspartate but not the glutamate mutant caused gain-of-function phenotypes. Here, we catalogued additional properties of these mutants to accrue greater insight into their functions. A modest increase in nuclear retention of E322K was noted. Binding of ERK2 E322K and D321N to a small group of substrates and regulatory proteins was similar, in spite of differences in CD site integrity. Interactions with a second docking site, the F site, which should be more accessible in E322K, were modestly reduced rather than increased. The crystal structure of ERK2 E322K also indicated a disturbed dimer interface, and reduced dimerization was detected by a two-hybrid test; yet, it was detected in dimers in EGF-treated cells, although to a lesser extent than D321N or wt ERK2. These findings indicate a range of small differences in behaviors that may contribute to increased function of E322K in certain cancers.

Dual-specificity phosphatase 26-dificient neurons are susceptible to oxygen-glucose deprivation/reoxygenation-evoked apoptosis and proinflammatory response by affecting the TAK1-medaited JNK/P38 MAPK pathway.

Dual-specificity phosphatase 26 (DUSP26) is linked to a broad range of human disorders as it affects numerous signaling cascades. However, the involvement of DUSP26 in ischemic stroke has not been explored. Here, we investigated DUSP26 as a key mediator of oxygen-glucose deprivation/reoxygenation (OGD/R)-associated neuronal injury, an in vitro model for investigating ischemic stroke. A decline in DUSP26 occurred in neurons suffering from OGD/R. A deficiency in DUSP26 rendered neurons more susceptible to OGD/R by aggravating neuronal apoptosis and inflammation, while the overexpression of DUSP26 blocked OGD/R-evoked neuronal apoptosis and inflammation. Mechanistically, enhanced phosphorylation of transforming growth factor-β-activated kinase 1 (TAK1), c-Jun N-terminal kinase (JNK) and P38 mitogen-activated protein kinase (MAPK) was evidenced in DUSP26-deficient neurons suffering from OGD/R, whereas the opposite effects were observed in DUSP26-overexpressed neurons. Moreover, the inhibition of TAK1 abolished the DUSP26-deficiency-elicited activation of JNK and P38 MAPK and exhibited anti-OGD/R injury effects in DUSP26-deficiency neurons. Results from these experiments show that DUSP26 is essential for neurons in defending against OGD/R insult, while neuroprotection is achieved by restraining the TAK1-mediated JNK/P38 MAPK pathway. Therefore, DUSP26 may serve as a therapeutic target for the management of ischemic stroke.

CDC14B is a favorable biomarker for recurrence and prognosis of GBM.

Glioblastoma (GBM) is the most common and lethal primary brain tumor in adults. The treatment options of GBM are quite few and the prognosis of GBM is very dismal. Identifying the effective and prognostic biomarker is important for molecular classification and individual treatment of patients. CDC14 is a conserved dual specificity phosphatase functioning mainly in mitosis and DNA respiration. The expression and function of CDC14 family in tumor progression is still elusive. In our study, we established a retrospective GBM cohort consisting of 135 patients who underwent the surgery and received standard treatment therapy. We compared the expression of CDC14A and CDC14B in GBM and tumor-adjacent tissues by retrieving data from TCGA and qPCR. With immunohistochemistry (IHC), we detected the expression of CDC14B in the cohort, and analyzed the correlation between CDC14B and clinicopathological factors by chi-square test. The significance of CDC14B on GBM recurrence and prognosis was assessed by univariate and multivariate analyses. CDC14B, but not CDC14A, had a higher expression in GBM tissues than in tumor-adjacent tissues. High CDC14B was correlated with high progression-free survival (PFS) rate and overall survival (OS) rate of GBM. In the Cox-regression model, CDC14B was an independent and favorable biomarker indicating low risk of recurrence and GBM-related death. High CDC14B is correlated with high GBM PFS and OS rate, and CDC14B is an independent biomarker of GBM, indicating low recurrence and favorable prognosis. Our study reveals a new biomarker of GBM which could indicate the recurrence and prognosis of GBM. This may help stratify the high-risk patients and modify the prognostic assessment based on molecular features.

MoMih1 is indispensable for asexual development, cell wall integrity, and pathogenicity of Magnaporthe oryzae.

Asexual spore serves as essential inoculum of rice blast during the disease cycle, and differentiation of young conidium from conidiophore is intimately regulated by cell cycle. Mih1 encodes a dual-specificity phosphatase that involved in the G2/M transition of the mitotic cell cycle by regulating the Cdk1 activity in eukaryotes. Till now, the roles of Mih1 homologue, however, remain unclear in Magnaporthe oryzae. We here functionally characterized the Mih1 homologue MoMih1 in M. oryzae. MoMih1 is localized to both the cytoplasm and nucleus and can physically interact with the CDK protein MoCdc28 in vivo. Loss of MoMih1 led to delayed nucleus division and a high level of Tyr15 phosphorylation of MoCdc28. The MoMih1 mutants showed retarded mycelial growth with a defective polar growth, less fungal biomass, and shorter distance between diaphragms, compared with the KU80. Asexual reproduction altered in MoMih1 mutants, with both abnormal conidial morphogenesis and decreased conidiation. The MoMih1 mutants severely attenuated the virulence to host plants due to the impaired ability of penetration and biotrophic growth. The incapability of scavenging of host-derived reactive oxygen species, which was possibly ascribed to the severely decreased extracellular enzymes activities, were partially associated with deficiency of pathogenicity. Besides, the MoMih1 mutants displayed also improper localization of retromer protein MoVps26 and polarisome component MoSpa2, and defects of cell wall integrity (CWI), melanin pigmentation, chitin synthesis, and hydrophobicity. In conclusion, our results demonstrate that MoMih1 plays pleiotropic roles during fungal development and plant infection of M. oryzae.

Knockdown of phosphatases of regenerating liver-1 prolongs the lifespan of Caenorhabditis elegans via activating DAF-16/FOXO.

Phosphatases of regenerating liver (PRLs) are dual-specificity protein phosphatases. The aberrant expression of PRLs threatens human health, but their biological functions and pathogenic mechanisms are unclear yet. Herein, the structure and biological functions of PRLs were investigated using the Caenorhabditis elegans (C. elegans). Structurally, this phosphatase in C. elegans, named PRL-1, consisted of a conserved signature sequence WPD loop and a single C(X)5 R domain. Besides, by Western blot, immunohistochemistry and immunofluorescence staining, PRL-1 was proved to mainly express in larval stages and express in intestinal tissues. Afterward, by feeding-based RNA-interference method, knockdown of prl-1 prolonged the lifespan of C. elegans but also improved their healthspan, such as locomotion, pharyngeal pumping frequency, and defecation interval time. Furthermore, the above effects of prl-1 appeared to be taken without acting on germline signaling, diet restriction pathway, insulin/insulin-like growth factor 1 signaling pathway, and SIR-2.1 but through a DAF-16-dependent pathway. Moreover, knockdown of prl-1 induced the nuclear translocation of DAF-16, and upregulated the expression of daf-16, sod-3, mtl-1, and ctl-2. Finally, suppression of prl-1 also reduced the ROS. In conclusion, suppression of prl-1 enhanced the lifespan and survival quality of C. elegans, which provides a theoretical basis for the pathogenesis of PRLs in related human diseases.

The SARS-CoV-2 Virus could Downregulate Dual Specificity Phosphatase-1 Expression in Oral Cancer: A Plausible Hypothesis that could Explain Oral Cancer Progression in the COVID-19 Pandemic and Post-pandemic Situation.

This study explores the downregulation of Dual Specificity Phosphatase-1 (DUSP-1) expression in oral cancer progression during the pandemic and post-pandemic situations. Keywords: COVID-19, Dual specificity phosphatase-1, Oral cancer, SARS-CoV-2.

Abstract P2-16-09: Dual Specific Phosphatase-7 (DUSP7/PYST2) and its role in regulating vascular endothelial functions

Abstract Dual Specific Phosphatase-7 (DUSP7/PYST2) and its role in regulating vascular endothelial functions Wenxiao Ji, Wen G. Jiang, Lin Ye, Tracey A. Martin CCMRC, Cardiff University School of Medicine, Cardiff, Wales, UK Introduction. Dual specific phosphatases (DUSPs) are a large family of enzyme able to trigger tyrosine phosphorylation, and phosphorylation of serine and/or threonine. This feature of a dual phosphorylation pattern by DUSPs, renders them with diverse roles in cells, from cytoskeletal regulation of cell migration, regulation of multiple kinases in cell signalling, to regulation of proteins such as microtubules and cell growth. We have investigated DUSP family members, in particular DUSP-7 (otherwise known as PYST2), identified from our studies as being one of prominent DUSPs found to be highly aberrant in certain cancer types including gastric cancer and pancreatic cancer. In breast cancer cells, DUSP7 has been reported as a potential factor linked to drug sensitivity. The role played by DUSP7 in vascular endothelial cells has been poorly studied. Here, we present our findings on the role of DUSP-7 in the regulation of biological functions of vascular endothelial cells. Methods. Human vascular endothelial cells were used in the present study. Cell sub-models were created by knock down of DUSP7. The cells were evaluated for their biological response to loss of DUSP7, including proliferation, migration, matrix adhesion and response to downstream signalling. DUSP7 responses to various exogenous factors were also evaluated by a protein kinase platform. Results. Knock down of DUSP7 in human endothelial cells rendered them manifesting significantly reduced matrix adhesiveness (p&amp;lt; 0.05) and most strikingly, reduced cellular migration (P&amp;lt; 0.0001, control versus DUSP7 knock down). Interestingly, there was little change with the rate of cell growth. When cells were tested by inhibiting a tight junctional molecule, HAVcR1, the endothelial cells responded with markedly reduced DUSP7 (reduction of 46%). Likewise, the cells were also exhibited reduced levels of DUSP7 after being challenged by exogenous metastasis related Kisspeptin, indicating that DUSP7 may participated the wide network of signalling and functional regulations shared with the tight junction regulator HAVcR1 and possibly utilising Mitogen-activated protein kinase 3 (MAPK3 or Extracellular signal regulated kinase-1). Conclusion. Dual specific phosphatase-7 has an important role to play in vascular endothelial cells, primarily on cell matrix adhesion and cellular migration. A possible route of regulation is by targeting the extracellular signalling network. Citation Format: WENXIAO JI, Wen G. Jiang, Lin Ye, Tracey A. Martin. Dual Specific Phosphatase-7 (DUSP7/PYST2) and its role in regulating vascular endothelial functions [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-16-09.

Abstract P4-08-22: Expression of Dual Specific Phosphatase-7 (DUSP7/PYST2) and it’s Connection with Salt Inducible Kinases (SIKs) and Downstream MKKs in breast cancer

Abstract Expression of Dual Specific Phosphatase-7 (DUSP7/PYST2) and it’s Connection with Salt Inducible Kinases (SIKs) and Downstream MKKs in breast cancer Wenxiao Ji1, Emily Ling Xin1,2, Lin Ye1, Eleri Davies3, Wen G. Jiang1, Tracey A. Martin1 1CCMRC, Cardiff University School of Medicine, Cardiff, Wales, UK 2Breast Centre, Peking University First Hospital, Xicheng District, Beijing, China 3Wales Breast Centre, University Llandough Hospital, Cardiff CF64 2XX, UK Introduction. DUSP7 is a member of the large Dual specific phosphatase family, able to regulate the phosphorylation of both tyrosine and serine/threonine protein kinases. The role of DUSP7 in cancer is not clear, however, it has been identified as a possible target for therapy in cancers including breast cancer. It has also been reported as having value in prognosis of certain cancers, such as haematological malignancies, breast cancer and certain types of gynaecological cancer. The signalling network for DUSP7 is not fully established but is known to connect to ERKs and MAP2Ks. DUSP7 also appears to be linked with salt inducible kinases (SIKs), a small family of kinases linked with progression and response to therapies in breast cancer. Thus, DUSP7 and salt inducible kinases may interact with each other and with the downstream kinases including MAP2Ks and STK11 to influence the clinical course of breast cancer. The present study explored if the pattern of DUSP7 together with salt inducible kinases and the downstream MKKs in breast cancer. Methods. The expression of DUSP7 was quantified in a cohort of breast cancer tissues (both normal mammary tissues and breast cancer tissues). The expression of the potential downstream kinases including MKK1, MKK2, MKK3, MKK4 and STK11 was also quantified. The expression profile of these molecule, together with the salt inducible kinases reported to be aberrant in our previous studies, were analysed against clinical and outcome information. Results. Breast cancer tissues expressed high levels of DUSP7 compared with normal mammary tissues, although not statistically significant. When we explored the relationship between DUSP7 and other potential related molecules in the database of the cohort, we found a highly significant correlation between DUSP7 and SIK1 (r=0.385, p&amp;lt; 0.001), SIK2 (r=0.590, p&amp;lt; 0.001), but not SIK3 (r=0.158, p&amp;gt;0.05). Together with SIK1 and SIK2 (known to link to drug sensitivity), DUSP7, MKK1 (MAP2K1) and MKK3 (MAP2K3) appear to form a gene signature that is of significant value in predicting the overall survival of the patients (ROC 0.723, p=0.001). This allowed us to significantly distinguish between those with good OS and poor OS (p&amp;lt; 0.001, Hazard Ration (HR) =1.443 (95%CI 1.154-1.804)). Multivariate analysis has shown that this signature is independent in predicting overall survival (p=0.013, HR=1.432). The signature is more significant in predicting OS in ER(-) tumours (p&amp;lt; 0.001) than ER(+) tumours (p=0.61). The same is seen when predicting OS with triple negative breast cancers (TNBC) (p&amp;lt; 0.001) than non-TNBC tumours (p=0.044). The gene signature also predicted disease free outcome (p=0.007, HR=1.266 (95% CI 1.065-1.504)). Conclusion. The dual specific phosphatase DUSP7 together with potentially correlated salt inducible kinases (SIK-1 and SIK-2) and downstream MKKs (MKK-1 and MKK3) have important clinical value in breast cancer. This provides support that DUSP7 may be a valuable therapeutic target in breast cancer. Citation Format: WENXIAO JI, Ling Xin, Eleri Davies, Wen G. Jiang, Lin Ye. Expression of Dual Specific Phosphatase-7 (DUSP7/PYST2) and it’s Connection with Salt Inducible Kinases (SIKs) and Downstream MKKs in breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-08-22.

MiR-216a-3p inhibits the proliferation and invasion of fibroblast-like synoviocytes by targeting dual-specificity phosphatase 5.

Dual-specificity phosphatase 5 (DUSP5) is a novel anti-inflammatory modulator in many inflammatory diseases. However, the role of DUSP5 in fibroblast-like synoviocytes (FLS) of rheumatoid arthritis (RA) remains unknown. In this study, we aimed to explore the biological function and regulation of DUSP5 in FLS. We found that lower DUSP5 expression level was detected in collagen-induced arthritis (CIA) and synoviocyte MH7A. Overexpression of DUSP5 markedly decreased the proliferation, migration, and invasion of MH7A, which correlated with suppressing the phosphorylation of extracellular signal-regulated kinase (ERK). Moreover, DUSP5 was identified as a novel target gene of miR-216a-3p, which was upregulated in FLS. Therefore, DUSP5 expression was negatively regulated by miR-216a-3p, and the effect of DUSP5 overexpression on FLS was reversed by miR-216a-3p mimics. Overall, our study demonstrates that DUSP5 is a miR-216a-3p target gene and its anti-inflammatory function in FLS via inactivation of ERK. These results revealed that the miR-216a-3p/DUSP5 pathway may play a crucial role in the malignant behavior of FLS, which may serve as a new target for the treatment of RA.