: The regulation of stomatal movement is one of the most important signaling networks in plants. The H+-ATPase at the plasma membrane of guard cells plays a critical role in the stomata opening, while there are some c...: The regulation of stomatal movement is one of the most important signaling networks in plants. The H+-ATPase at the plasma membrane of guard cells plays a critical role in the stomata opening, while there are some conflicting results regarding the effectiveness of the plasma membrane H+-ATPase inhibitor, vanadate, in inhibiting stomata opening. We observed that 2 mmol/L vanadate hardly inhibited light-stimulated stomata opening in epidermal peels of Vicia faba L., but significantly inhibited dark- and ABA-induced stomatal closure. These results cannot be explained with the previous findings that H+-ATPase was inhibited by vanadate. In view of the fact that vanadate is an inhibitor of protein tyrosine phosphatases (PTPases), we investigated whether the stomatal movement regulated by vanadate is through the regulation of PTPase. As expected, phenylarsine oxide (PAO), a specific inhibitor of PTPase, has very similar effects and even more effective than vanadate. Typical PTPase activity was found in guard cells of V. faba; moreover, the phosphatase activity could be inhibited by both vanadate and PAO. These results not only provide a novel explanation for conflicting results about vanadate modulating stomatal movement, but also provide further evidence for the involvement of PTPases in modulating signal transduction of stomatal movement.展开更多
BACKGROUND Centromere protein A(CENPA)exhibits an increased expression level in primary human rectal cancer tissues,but its role has not been investigated.AIM To clarify the specific role and mechanism of CENPA in rec...BACKGROUND Centromere protein A(CENPA)exhibits an increased expression level in primary human rectal cancer tissues,but its role has not been investigated.AIM To clarify the specific role and mechanism of CENPA in rectal cancer progression.METHODS CENPA protein expression in rectal cancer tissues and cell lines were detected.CENPA was overexpressed and knocked down in SW837 and SW480 cells,and proliferation,invasion,apoptosis and epithelial-mesenchymal transition(EMT)marker protein levels were examined.O6-methylguanine DNA methyltransferase(MGMT)promoter methylation was assessed with methylation-specific poly-merase chain reaction.Co-immunoprecipitation assay verified the interaction between MGMT and protein tyrosine phosphatase nonreceptor type 4(PTPN4).SW837 cells with CENPA knockdown were injected subcutaneously into mice,and tumor growth was examined.RESULTS CENPA was upregulated in rectal cancer tissues and cell lines.CENPA overex-pression promoted proliferation,invasion and EMT,and inhibited apoptosis in rectal cancer cells.Whereas CENPA knockdown showed the opposite results.Moreover,CENPA inhibited MGMT expression by promoting DNA methyltrans-ferase 1-mediated MGMT promoter methylation.MGMT knockdown abolished the CENPA knockdown-mediated inhibition of rectal cancer cell progression.MGMT increased PTPN4 protein stability by inhibiting PTPN4 ubiquitination degradation via competing with ubiquitin-conjugating enzyme E2O for interacting with PTPN4.PTPN4 knockdown abolished the inhibitory effects of MGMT overexpression on rectal cancer cell progression.Moreover,CENPA knockdown inhibited xenograft tumor growth in vivo.CONCLUSION CENPA knockdown inhibited rectal cancer cell growth and attenuated xenograft tumor growth through regulating the MGMT/PTPN4 axis.展开更多
In this editorial,the roles of protein tyrosine phosphatase nonreceptor 2(PTPN2)in oncogenic transformation and tumor behavior and its potential as a therapeutic target in the context of gastrointestinal(GI)cancers ar...In this editorial,the roles of protein tyrosine phosphatase nonreceptor 2(PTPN2)in oncogenic transformation and tumor behavior and its potential as a therapeutic target in the context of gastrointestinal(GI)cancers are presented with respect to the article by Li et al published in ninth issue of the World Journal of Gastrointestinal Oncology.PTPN2 is a member of the protein tyrosine phosphatase family of signaling proteins that play crucial roles in the regulation of inflammation and immunity.Accordingly,early findings highlighted the contribution of PTPN2 to the pathogenesis of inflammatory and autoimmune disorders related to its dysfunction.On the other hand,recent studies have indicated that PTPN2 has many different roles in different cancer types,which is associated with the complexity of its regulatory network.PTPN2 dephosphorylates and inactivates EGFR,SRC family kinases,JAK1 and JAK3,and STAT1,STAT3,and STAT5 in cell type-and context-dependent manners,which indicates that PTPN2 can perform either prooncogenic or anti-oncogenic functions depending on the tumor subtype.While PTPN2 has been suggested as a potential therapeutic target in cancer treatment,to the best of ourknowledge,no clear treatment protocol has referred to PTPN2.Although there are only few studies that investigated PTPN2 expression in the GI system cancers,which is a potential limitation,the association of this protein with tumor behavior and the influence of PTPN2 on many therapy-related signaling pathways emphasize that PTPN2 could serve as a new molecular biomarker to predict tumor behavior and as a target for therapeutic intervention against GI cancers.In conclusion,more studies should be performed to better understand the prognostic and therapeutic potential of PTPN2 in GI tumors,especially in tumors resistant to therapy.展开更多
Protein tyrosine phosphatases(PTPs)remove phosphate groups from protein tyrosine residues to regulate various cell signaling processes,subsequently affecting the growth,metabolism,differentiation,immune response,and o...Protein tyrosine phosphatases(PTPs)remove phosphate groups from protein tyrosine residues to regulate various cell signaling processes,subsequently affecting the growth,metabolism,differentiation,immune response,and other cellular processes.Several studies have investigated the functions of PTPs in tumor and organism immunity.However,only a few studies have focused on their roles in reproductive disorders.Therefore,in this review,we summarize the roles and underlying molecular mechanisms of PTPs in infertility,spontaneous abortion,pregnancy-induced hypertension,gestational diabetes mellitus,early embryonic developmental abnormalities,and preterm birth.This review can contribute to future research on PTPs and their potential applications as targets in the treatment of reproductive diseases.展开更多
Background:Tyrosine phosphorylation of intracellular proteins is a posttranslational modification that plays a regulatory role in signal transduction during cellular events.Dephosphorylation of signal transduction pro...Background:Tyrosine phosphorylation of intracellular proteins is a posttranslational modification that plays a regulatory role in signal transduction during cellular events.Dephosphorylation of signal transduction proteins caused by protein tyrosine phosphatases(PTPs)contributed their role as a convergent node to mediate cross-talk between signaling pathways.In the context of cancer,PTP-mediated pathways have been identified as signaling hubs that enabled cancer cells to mitigate stress induced by clinical therapy.This is achieved by the promotion of constitutive activation of growth-stimulatory signaling pathways or modulation of the immune-suppressive tumor microenvironment.Preclinical evidences suggested that anticancer drugs will release their greatest therapeutic potency when combined with PTP inhibitors,reversing drug resistance that was responsible for clinical failures during cancer therapy.Areas covered:This review aimed to elaborate recent insights that supported the involvement of PTP-mediated pathways in the development of resistance to targeted therapy and immune-checkpoint therapy.Expert opinion:This review proposed the notion of PTP inhibition in anticancer combination therapy as a potential strategy in clinic to achieve long-term tumor regression.Ongoing clinical trials are currently underway to assess the safety and efficacy of combination therapy in advanced-stage tumors.展开更多
An organic layer prepared from the seed of Aceriphyllum rossii was studied to identify the active compounds for protein tyrosine phosphatase 1B（PTP1B） inhibition.Bioassay guided fractionation resulted in the isolati...An organic layer prepared from the seed of Aceriphyllum rossii was studied to identify the active compounds for protein tyrosine phosphatase 1B（PTP1B） inhibition.Bioassay guided fractionation resulted in the isolation of PTP1B inhibitory activity of triterpenes（1-4）.These four compounds were identified as aceriphyllic acid C（1）,aceriphyllic acid D（2）,aceriphyllic acid E（3） and aceriphyllic acid F（4）.The isolated 1-4 compounds inhibited PTP1B with IC50 values ranged from（2.1±1.5） μmol/L to（11.2±2.5） μmol/L.Kinetic analysis of PTP1B inhibition by aceriphyllic acid C（1） and aceriphyllic acid D（2） suggested that oleanane-type triterpenes inhibited PTP1B activity in a mixed-type manner.展开更多
Seven oleanene triterpenes were isolated from the roots of Potentilla discolor Bge and their structures were identified as 3-oxoolean-12-en-27-oic acid（1）, gypsogenic acid（2）, 3α-hydroxyolean-12-en-27-oic acid（3...Seven oleanene triterpenes were isolated from the roots of Potentilla discolor Bge and their structures were identified as 3-oxoolean-12-en-27-oic acid（1）, gypsogenic acid（2）, 3α-hydroxyolean-12-en-27-oic acid（3）, 3β-hydroxyolean-12-en-27-oic acid（4）, aceriphyllic acid A（5）, aceriphyllic acid A methyl ester（6）, and oleanolic acid（7）. Compounds 1–7 inhibited protein tyrosine phosphatase 1B（PTP1B） activity, with IC50 values ranging from（7.5±0.5） to（22.7±0.5） μmol/L. Among the isolates, compounds 1, 2, 3 and 7 from the Potentilla discolor Bge were found to exhibit selective PTP1 B inhibitory activity.展开更多
AIMTo evaluate whether protein tyrosine phosphatase 1B (PTP1B) contributed to initiate human retinal pigment epithelium cells (A)-19 migration and investigate the signaling pathways involved in this process.METHODSARP...AIMTo evaluate whether protein tyrosine phosphatase 1B (PTP1B) contributed to initiate human retinal pigment epithelium cells (A)-19 migration and investigate the signaling pathways involved in this process.METHODSARPE-19 cells were cultured and treated with the siRNA-PTP1B. Expression of PTP1B was confirmed by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). AG1478 [a selective inhibitor of epidermal growth factor receptor (EGFR)] and PD98059 (a specific inhibitor of the activation of mitogen-activated protein kinase) were used to help to determine the PTP1B signaling mechanism. Western blot analysis verified expression of EGFR and extracellular signal-regulated kinase (ERK) in ARPE-19 cells. The effect of siRNA-PTP1B on cell differentiation was confirmed by immunostaining for α-smooth muscle actin (α-SMA) and qRT-PCR. Cell migration ability was analyzed by transwell chamber assay.RESULTSThe mRNA levels of PTP1B were reduced by siRNA-PTP1B as determined by qRT-PCR assay. SiRNA-PTP1B activated EGFR and ERK phosphorylation. α-SMA staining and qRT-PCR assay demonstrated that siRNA-PTP1B induced retinal pigment epithelium (RPE) cells to differentiate toward better contractility and motility. Transwell chamber assay proved that PTP1B inhibition improved migration activity of RPE cells. Treatment with AG1478 and PD98059 abolished siRNA-PTP1B-induced activation of EGFR and ERK, α-SMA expression and cell migration.CONCLUSIONPTP1B inhibition promoted myofibroblast differentiation and migration of ARPE-19 cells, and EGFR/ERK signaling pathway played important role in migration process.展开更多
This study is focused on the expression of an SH2 domain-truncated form of protein tyrosine phosphatase SHP-1（designated ΔSHP-1） and the preparation of its polyclonal antibodies. A cDNA fragment encoding ΔSHP-1 wa...This study is focused on the expression of an SH2 domain-truncated form of protein tyrosine phosphatase SHP-1（designated ΔSHP-1） and the preparation of its polyclonal antibodies. A cDNA fragment encoding ΔSHP-1 was amplified by PCR and then cloned into the pT7 expression vector. The recombinant pT7-ΔSHP-1 plasmid was used to transform Rosetta（DE3） E. coli cells. ΔSHP-1 was distributed in the exclusion body of E. coli cell extracts and was purified through a two-column chromatographic procedure. The purified enzyme exhibited an expected molecular weight on SDS-gels and HPLC gel filtration columns. It possesses robust tyrosine phosphatase activity and shows typical enzymatic characteristics of classic tyrosine phosphatases. To generate polyclonal anti-ΔSHP-1 antibodies, purified recombinant ΔSHP-1 was used to immunize a rabbit. The resultant anti-serum was subjected to purification on ΔSHP-1 antigen affinity chromatography. The purified polyclonal antibody displayed a high sensitivity and specificity toward ΔSHP-1. This study thus provides the essential materials for further investigating the biological function and pathological implication of SHP-1 and screening the inhibitors and activators of the enzyme for therapeutic drug development.展开更多
The protein tyrosine phosphatase 1B（PTP1B）is an important regulator of metabolism.The relationship between PTP1B and tumors is quite complex.The purpose of this study is to explore the expression pattern and role of...The protein tyrosine phosphatase 1B（PTP1B）is an important regulator of metabolism.The relationship between PTP1B and tumors is quite complex.The purpose of this study is to explore the expression pattern and role of PTP1B in breast cancer.The expression of PTP1B was detected in 67 samples of breast cancer tissue by Western blot.Cell growth assay,Transwell migration assay,and Scratch motility assay were used to examine the proliferation and migration of MCF-7 with and without PTP1B.The total levels and phosphorylated levels of signal transduction and activator of transcription 3（STAT3）and the expression of C-C motif chemokine ligand 5（CCL5）were also examined by Western blot.PTP1B was overexpressed in over 70%of breast cancer tissues,correlating with patients with estrogen receptor（ER）-negative,progesterone receptor（PR）-negative,and human epidermal growth factor receptor 2（HER2）-positive tumors.The data also showed that both tumor size and lymph node metastasis were significantly higher in patients with a higher level of PTP1B.The proliferation and migration of MCF-7 cells were found to be inhibited after knocking down the gene of PTP1B.Our data also showed that PTP1B could up-regulate the dephosphorylated level of STAT3,which could increase the expression of CCL5.These phenomena indicated that PTP1B may play a crucial role in the development of breast cancer.展开更多
BACKGROUND The incidence of primary liver cancer is increasing year by year.In 2022 alone,more than 900000 people were diagnosed with liver cancer worldwide,with hepatocellular carcinoma(HCC)accounting for 75%-85%of c...BACKGROUND The incidence of primary liver cancer is increasing year by year.In 2022 alone,more than 900000 people were diagnosed with liver cancer worldwide,with hepatocellular carcinoma(HCC)accounting for 75%-85%of cases.HCC is the most common primary liver cancer.China has the highest incidence and mortality rate of HCC in the world,and it is one of the malignant tumors that seriously threaten the health of Chinese people.The onset of liver cancer is occult,the early cases lack typical clinical symptoms,and most of the patients are already in the middle and late stage when diagnosed.Therefore,it is very important to find new markers for the early detection and diagnosis of liver cancer,improve the therapeutic effect,and improve the prognosis of patients.Protein tyrosine phosphatase non-receptor 2(PTPN2)has been shown to be associated with colorectal cancer,triple-negative breast cancer,non-small cell lung cancer,and prostate cancer,but its biological role and function in tumors remain to be further studied.AIM To combine the results of relevant data obtained from The Cancer Genome Atlas(TCGA)to provide the first in-depth analysis of the biological role of PTPN2 in HCC.METHODS The expression of PTPN2 in HCC was first analyzed based on the TCGA database,and the findings were then verified by immunohistochemical staining,quantitative real-time polymerase chain reaction(qRT-PCR),and immunoblotting.The value of PTPN2 in predicting the survival of patients with HCC was assessed by analyzing the relationship between PTPN2 expression in HCC tissues and clinicopathological features.Finally,the potential of PTPN2 affecting immune escape of liver cancer was evaluated by tumor immune dysfunction and exclusion and immunohistochemical staining.RESULTS The results of immunohistochemical staining,qRT-PCR,and immunoblotting in combination with TCGA database analysis showed that PTPN2 was highly expressed and associated with a poor prognosis in HCC patients.Kyoto Encyclopedia of Genes and Genomes enrichment analysis showed that PTPN2 was associated with various pathways,including cancer-related pathways,the Notch signaling pathway,and the MAPK signaling pathway.Gene Set Enrichment Analysis showed that PTPN2 was highly expressed in various immune-related pathways,such as the epithelial mesenchymal transition process.A risk model score based on PTPN2 showed that immune escape was significantly enhanced in the high-risk group compared with the low-risk group.CONCLUSION This study investigated PTPN2 from multiple biological perspectives,revealing that PTPN2 can function as a biomarker of poor prognosis and mediate immune evasion in HCC.展开更多
Oleanolic acid derivatives act as newer protein tyrosine phosphatase 1B （PTP-1B） inhibitors for type 2 diabetes mellitus （T2DM）. In order to understand the structural requirement of PTP-1B inhibitors, 52 oleanolic...Oleanolic acid derivatives act as newer protein tyrosine phosphatase 1B （PTP-1B） inhibitors for type 2 diabetes mellitus （T2DM）. In order to understand the structural requirement of PTP-1B inhibitors, 52 oleanolic acid derivatives were divided into a training set （34 compounds） and a test set （18 compounds）. The highly reliable and predictive 3D-QSAR models were constructed by CoMFA, CoMSIA and topomer CoMFA methods, respectively. The results showed that the cross validated coefficient （q2） and non-cross-validated coefficient （R2） were 0.554 and 0.999 in the CoMFA model, 0.675 and 0.971 in the CoMSIA model, and 0.628 and 0.939 in the topomer CoMFA model, which suggests that three models are robust and have good exterior predictive capabilities. Furthermore, ten novel inhibitors with much higher inhibitory potency were designed. Our design strategy was that （i） the electronegative substituents （Cl, -CH2OH, OH and -CH2Cl） were introduced into the double bond of ring C, （ii） the hydrogen bond acceptor groups （C≡N and N atom）, electronegative groups （C≡N, N atom, -COOH and -COOCH3） and bulky substituents （C6H5N） were connected to the C-3 position, which would result in generating potent and selective PTP-1B inhibitors. We expect that the results in this paper have the potential to facilitate the process of design and to develop new potent PTP-1B inhibitors.展开更多
3-bromo-4,5-bis（2,3-dibromo-4,5-dihydroxybenzyl）-l,2-benzenediol （1） is a natural bromophenol isolated from the red algae Rhodomela confervoides that exhibits significant inhibition against protein tyrosine phosph...3-bromo-4,5-bis（2,3-dibromo-4,5-dihydroxybenzyl）-l,2-benzenediol （1） is a natural bromophenol isolated from the red algae Rhodomela confervoides that exhibits significant inhibition against protein tyrosine phosphatase 1B （PTP1B）. Based on its activity, we synthesized two new synthetic bromophenols and their methoxy derivatives from vanillin using the structure of natural bromophenol 1 as a scaffold. The structures of these bromophenols were elucidated from H NMR, 13C NMR, and high resolution electron ionization mass spectrometry as 2,3-dibromo-1-（2＇-bromo-6＇-（3＂,4＂-dimethoxybenzyl）- 3 ＇,4 ＇-dimethoxybenzyl）-4,5 -dimethoxybenzene （2）, 2,3-dibromo- 1 -（2 ＇-bromo-6＇-（2 ＂-bromo-4＂,5 ＂-dimethoxy- benzyl）-3＇,4＇-dimethoxybenzyl）-4,5-dimethoxybenzene （3）, 3,4-dibromo-5-（2＇-bromo-6＇-（2＂-bromo-4＂,5＂- dihydroxybenzyl）-3＇,4＇-dihydroxybenzyl）pyrocatechol （4） and 3,4-dibromo-5-（2＇-bromo-6＇-（3＂,4＂- dihydroxybenzyl）-3＇,4＇-dihydroxybenzyl）pyrocatechol （5）. PTP1B inhibition activities of these compounds were evaluated using a colorimetric assay, and compounds 3 and 4 demonstrated interesting activity against PTP1B.展开更多
Objective To study the expression level of peptidylarginine deiminase 4(PADI4) and protein tyrosine phosphatase nonreceptor type 22(PTPN22) in the synovium of rat model of collagen-induced arthritis, and to explore th...Objective To study the expression level of peptidylarginine deiminase 4(PADI4) and protein tyrosine phosphatase nonreceptor type 22(PTPN22) in the synovium of rat model of collagen-induced arthritis, and to explore their possible therapeutic role in rheumatoid arthritis. Methods Thirty-two female Wistar rats weighing 100±20 g were randomly assigned into 3-week collagen-induced arthritis(CIA) model group(n=8), 4-week CIA model group(n=8), 6-week CIA model group(n=8), and the control group(n=8). The body weight changes of each group were recorded. The expression levels of PADI4 and PTPN22 were detected and compared by the methods of immunohistochemical staining and Western blot. Results Arthritis of rat began to form 14 days after sensitization and the joint swelling reached peak at 28 days. The weights of the rats slowly grew both in CIA model groups and the control group. Immunohistochemical staining results showed that the positive expression of PADI4 and PTPN22 was mainly located in cartilage peripheral mononuclear cells, the cytoplasm of infiltrated cells, and bone marrow cavity. There were significant differences in the optical density of PADI4 and PTPN22 among CIA model groups and the control group(PADI4, 0.2898±0.012, 0.2982±0.022, 0.2974±0.031, 0.2530±0.013 in 3-week CIA model, 4-week CIA model, 6-week CIA model and control groups; PTPN22, 0.2723±0.004, 0.2781±0.010, 0.2767±0.008, 0.2422±0.019; all P <0.05). The expression bands of PADI4 were observed in Western blot 3 weeks after initial immunization, the thickest in the 4th week, and decreased in the 6th week. The expression bands of PTPN2 were observed at all the time points, with no obvious time-dependent trend. Conclusions PADI4 and PTPN22 are obviously correlated with CIA in rat model. PADI4 is expressed at early stage of the disease, while the expression of PTPN22 sustains throughout the course.展开更多
This study objective was to express and characterize the catalytic domain of the human T cell protein tyrosine phosphatase（△TC-PTP） and to study immunohistochemically the expression of △TC-PTP in human non-small c...This study objective was to express and characterize the catalytic domain of the human T cell protein tyrosine phosphatase（△TC-PTP） and to study immunohistochemically the expression of △TC-PTP in human non-small cell lung cancers. △TC-PTP gene was PCR amplified with the cDNA of human TC-PTP as template, and cloned into the pT7 expression vector. The recombinant pT7-△TC-PTP was expressed in E. coli Rosetta （ DE3 ） host cells and puri- fied. The enzymatic characteristics of △TC-PTP including enzyme activity and kinetics assay were measured. The antiserum was prepared by immunizing rabbit with the purified recombinant △TC-PTP. Rabbit polyclonal antibody against △TC-PTP was purified by PVDF immobilized antigen affinity chromatography. Immunohistochemical staining of lung cancer tissues was performed with antibody against △TC-PTP protein. △TC-PTP gene was correctly cloned, expressed, and purified. The recombinant △TC-PTP had a highly catalytic activity of PTPase. Squamous cell lung carcinoma showed a significantly higher expression rate of △TC-PTP （76. 92%, 10/13 ） than adenocarcinoma （57.14%, 4/7） and normal lung tissue（20%, 1/5 ）. This study represents the first demonstration that △TC-PTP is highly expressed in human squamous cell lung carcinomas. In addition, this study provides an important basis for further studying the biological function of TC-PTP and its relationship with lung carcinomas and other diseases.展开更多
PTPMEGI is an intracellular protein tyrosine phosphatase（PTP）, which contains FERM and PDZ domains This study focuses our attention on the expression, purification and characterization of catalytic domain of PTPMEG1...PTPMEGI is an intracellular protein tyrosine phosphatase（PTP）, which contains FERM and PDZ domains This study focuses our attention on the expression, purification and characterization of catalytic domain of PTPMEG1 （AMEG1） and preparation of its polyclonal antibody. A cDNA fragment encoding AMEG1 protein（amino acid residues 643-926） was amplified by PCR and then cloned into the pT7-7 vector. Both soluble and insoluble recombinant AMEG1 proteins were observed after induction by IPTG. Soluble AMEG1 was purified via two chromatographic steps, and the purified enzyme was characterized. With para-nitrophenylphosphate（pNPP） as a substrate, AMEG1 exhibited typical enzymatic characteristics of classic PTPs and classical Michaelis-Menten kinetics. Insoluble AMEG1, which was mainly distributed in the inclusion body of E. coli cells extracts, was purified by preparative electrophoresis gel for the preparation of the polyclonal antibody. A rabbit was immunized with AMEG1 purified by preparative electrophoresis to generate anti-AMEG1 antibody. Anti-serum was collected on 28th day after initial injection and purified via affinity chromatography. The purified polyconal antibody displayed a satisfactory titer and sensitivity.展开更多
Proteintyrosine phosphatase 1B(PTP1B)inhibitionis consideredas a potentialtherapeuticfor the treatmentof cancer,type2 diabetes,andobesity.Inour presentwork,weinvestigatedtheanti-diabeticpotentialof8-hydroxydiospyrin(8...Proteintyrosine phosphatase 1B(PTP1B)inhibitionis consideredas a potentialtherapeuticfor the treatmentof cancer,type2 diabetes,andobesity.Inour presentwork,weinvestigatedtheanti-diabeticpotentialof8-hydroxydiospyrin(8-HDN)from D.lotus against the PTP1B enzyme.It showed significant inhibitory activity of PTP1B with an IC 50 value of 18.37±0.02μM.A detailed molecular docking study was carried out to analyze the binding orientation,binding energy,and mechanism of inhibition.A comparative investigation of 8-HDN in the catalytic,as well as the allosteric site of PTP1B,was performed.Binding energy data showed that compound 8-HDN is more selective for the allosteric site and hence avoids the problems associated with catalytic site inhibition.The inhibition mechanism of 8-HDN can be further investigated as an active lead compound against PTP1B by using in vitro and in vivo models.展开更多
A DNA fragment encoding the intracellular part of tyrosine phosphatase RPTPα designated as RPTPα-2D gene was amplified by PCR from a human prostate cDNA library and cloned into the pT7 E. coli expression vector. The...A DNA fragment encoding the intracellular part of tyrosine phosphatase RPTPα designated as RPTPα-2D gene was amplified by PCR from a human prostate cDNA library and cloned into the pT7 E. coli expression vector. The resulting plasmid pT7-RPTPα-2D was used to transform Rosetta DE3 E. coli cells. RPTPα-2D was predominately expressed in the insoluble inclusion body and was effectively purified using preparative electrophoresis gels. Polyclonal antibodies were obtained after immunization of a rabbit with purified RPTPα-2D. The antibodies displayed a high titer and sensitivity. This study thus provided a valuable tool for further researches on RPTPα.展开更多
This study focuses on the expression of human protein tyrosine phosphatase 1B （PTP1 B） catalytic domain （△PTP1B） and preparation of polyclonal antibody against △PTP1B. △PTP1B gene was PCR amplified with the cDN...This study focuses on the expression of human protein tyrosine phosphatase 1B （PTP1 B） catalytic domain （△PTP1B） and preparation of polyclonal antibody against △PTP1B. △PTP1B gene was PCR amplified with the cDNA of human PTP1B as the template, and cloned into the pT7 expression vector. The recombinant pT7-△PTP1B was expressed in E. eoli Rosetta（ DE3 ） host cells and purified. The antiserum was prepared by immunizing rabhit with purified recombinant △PTP1B. The polyclonal antibody against △PTP1B was purified by PVDF immobilized antigen affinity chromatography. △PTP1B was correctly cloned, expressed, and purified as confirmed by PCR, DNA sequence analysis, SDS-PAGE western blotting, and ILPLC. The titer and sensitivity of the antibody were 1：2500（ volume ratio） and 0. 1 ng, respectively. This study provides an important basis for further studying the biological function of PTP1B and its relationship with human diseases.展开更多
Background Long QT syndrome(LQTS)is a potentially fatal cardiac ion channel disease.Mutations in the gene encoding cardiac hERG potassium channel are the second most common causes of LQTS.Cardiac hERG potassium channe...Background Long QT syndrome(LQTS)is a potentially fatal cardiac ion channel disease.Mutations in the gene encoding cardiac hERG potassium channel are the second most common causes of LQTS.Cardiac hERG potassium channel conducts the rapidly activating delayed rectifier potassium current(Ikr),which is one of the crucial currents in rapid repolarization phase of action potential in human cardiomyocytes.Function of hERG potassium channel is regulated by a variety of signaling pathways,in which phosphorylation and dephosphorylation of tyrosine proteins plays a major role.Previous research has found that non-receptor protein tyrosine phosphatase(PTPN)can interact with hERG potassium channel in cardiac cells.The aims of the present study were to investigate the regulatory effect of protein tyrosine phosphatase non-receptor type 12,11 and 6(PTPN12,PTPN11 and PTPN6)on cardiac hERG potassium channels.Methods HEK-293 cells were transfected with pcDNA3.0-hERG by Lipofectamine 2000 and selected by G418.HEK-293/hERG cells stably expressing hERG protein were then transfected with pcDNA3.1-PTPN12-RFP,pcDNA3.1-PTPN11-EGFP and pcDNA3.1-PTPN6-EGFP,respectively.Forty-eight hours after transfection,immunofluorescence assay and western blot were performed to detect the expression of hERG channel proteins and PTPN proteins.hERG channel currents in hERG alone-expressing group,PTPN12-,PTPN11-and PTPN6-overexpressing groups,as well as inhibitor groups were recorded by patch clamp technique.Results The maximum pulse current densities of PTPN12-,PTPN11-and PTPN6-overexpressing groups were all decreased when compared with hERG alone-expressing group(P<0.05).However,the maximum pulse current densities of inhibitor groups were all increased when compared with PTPN12-,PTPN11-and PTPN6-overexpressing groups,respectively(P<0.05).Conclusions Overexpression of PTPN12,PTPN11 and PTPN6 reduced the current density of hERG potassium channel,while this effect could be reversed by tyrosine phosphatase inhibitors.These results suggested that PTPN12,PTPN11 and PTPN6 negatively regulated hERG potassium channel currents by catalyzing the dephosphorylation process of hERG potassium channels.[S Chin J Cardiol 2021;22(1):38-49]展开更多
基金国家自然科学基金，Doctor's Fund of College and University Education
文摘: The regulation of stomatal movement is one of the most important signaling networks in plants. The H+-ATPase at the plasma membrane of guard cells plays a critical role in the stomata opening, while there are some conflicting results regarding the effectiveness of the plasma membrane H+-ATPase inhibitor, vanadate, in inhibiting stomata opening. We observed that 2 mmol/L vanadate hardly inhibited light-stimulated stomata opening in epidermal peels of Vicia faba L., but significantly inhibited dark- and ABA-induced stomatal closure. These results cannot be explained with the previous findings that H+-ATPase was inhibited by vanadate. In view of the fact that vanadate is an inhibitor of protein tyrosine phosphatases (PTPases), we investigated whether the stomatal movement regulated by vanadate is through the regulation of PTPase. As expected, phenylarsine oxide (PAO), a specific inhibitor of PTPase, has very similar effects and even more effective than vanadate. Typical PTPase activity was found in guard cells of V. faba; moreover, the phosphatase activity could be inhibited by both vanadate and PAO. These results not only provide a novel explanation for conflicting results about vanadate modulating stomatal movement, but also provide further evidence for the involvement of PTPases in modulating signal transduction of stomatal movement.
基金This study was reviewed and approved by the Ethic Committee of Medical College of Henan Vocational University of Science and Technology(Approval No.HVUYL414101416920231017001)all participants signed a written informed consent.
文摘BACKGROUND Centromere protein A(CENPA)exhibits an increased expression level in primary human rectal cancer tissues,but its role has not been investigated.AIM To clarify the specific role and mechanism of CENPA in rectal cancer progression.METHODS CENPA protein expression in rectal cancer tissues and cell lines were detected.CENPA was overexpressed and knocked down in SW837 and SW480 cells,and proliferation,invasion,apoptosis and epithelial-mesenchymal transition(EMT)marker protein levels were examined.O6-methylguanine DNA methyltransferase(MGMT)promoter methylation was assessed with methylation-specific poly-merase chain reaction.Co-immunoprecipitation assay verified the interaction between MGMT and protein tyrosine phosphatase nonreceptor type 4(PTPN4).SW837 cells with CENPA knockdown were injected subcutaneously into mice,and tumor growth was examined.RESULTS CENPA was upregulated in rectal cancer tissues and cell lines.CENPA overex-pression promoted proliferation,invasion and EMT,and inhibited apoptosis in rectal cancer cells.Whereas CENPA knockdown showed the opposite results.Moreover,CENPA inhibited MGMT expression by promoting DNA methyltrans-ferase 1-mediated MGMT promoter methylation.MGMT knockdown abolished the CENPA knockdown-mediated inhibition of rectal cancer cell progression.MGMT increased PTPN4 protein stability by inhibiting PTPN4 ubiquitination degradation via competing with ubiquitin-conjugating enzyme E2O for interacting with PTPN4.PTPN4 knockdown abolished the inhibitory effects of MGMT overexpression on rectal cancer cell progression.Moreover,CENPA knockdown inhibited xenograft tumor growth in vivo.CONCLUSION CENPA knockdown inhibited rectal cancer cell growth and attenuated xenograft tumor growth through regulating the MGMT/PTPN4 axis.
文摘In this editorial,the roles of protein tyrosine phosphatase nonreceptor 2(PTPN2)in oncogenic transformation and tumor behavior and its potential as a therapeutic target in the context of gastrointestinal(GI)cancers are presented with respect to the article by Li et al published in ninth issue of the World Journal of Gastrointestinal Oncology.PTPN2 is a member of the protein tyrosine phosphatase family of signaling proteins that play crucial roles in the regulation of inflammation and immunity.Accordingly,early findings highlighted the contribution of PTPN2 to the pathogenesis of inflammatory and autoimmune disorders related to its dysfunction.On the other hand,recent studies have indicated that PTPN2 has many different roles in different cancer types,which is associated with the complexity of its regulatory network.PTPN2 dephosphorylates and inactivates EGFR,SRC family kinases,JAK1 and JAK3,and STAT1,STAT3,and STAT5 in cell type-and context-dependent manners,which indicates that PTPN2 can perform either prooncogenic or anti-oncogenic functions depending on the tumor subtype.While PTPN2 has been suggested as a potential therapeutic target in cancer treatment,to the best of ourknowledge,no clear treatment protocol has referred to PTPN2.Although there are only few studies that investigated PTPN2 expression in the GI system cancers,which is a potential limitation,the association of this protein with tumor behavior and the influence of PTPN2 on many therapy-related signaling pathways emphasize that PTPN2 could serve as a new molecular biomarker to predict tumor behavior and as a target for therapeutic intervention against GI cancers.In conclusion,more studies should be performed to better understand the prognostic and therapeutic potential of PTPN2 in GI tumors,especially in tumors resistant to therapy.
基金the National Natural Science Foundation of China(82371699 and 82120108011)National Key Research and Development Project(2022YFC2704602 and 2022YFC2704502)+1 种基金Major Project of Shanghai Municipal Education Commission’s Scientific Research and Innovation Plan(2021-01-07-00-07-E00144)Strategic Collaborative Research Program of the Ferring Institute of Reproductive Medicine(FIRMA200502)。
文摘Protein tyrosine phosphatases(PTPs)remove phosphate groups from protein tyrosine residues to regulate various cell signaling processes,subsequently affecting the growth,metabolism,differentiation,immune response,and other cellular processes.Several studies have investigated the functions of PTPs in tumor and organism immunity.However,only a few studies have focused on their roles in reproductive disorders.Therefore,in this review,we summarize the roles and underlying molecular mechanisms of PTPs in infertility,spontaneous abortion,pregnancy-induced hypertension,gestational diabetes mellitus,early embryonic developmental abnormalities,and preterm birth.This review can contribute to future research on PTPs and their potential applications as targets in the treatment of reproductive diseases.
基金National Natural Science Foundation of China,Grant/Award Numbers:82273770,22177083Natural Science Foundation of Sichuan Province,Grant/Award Number:2022NSFSC1290+3 种基金135 Project for Disciplines of Excellence–Clinical Research Incubation ProjectWest China HospitalWest China Nursing Discipline Development Special Fund ProjectSichuan University,Grant/Award Numbers:ZYJC21016,HXHL21011。
文摘Background:Tyrosine phosphorylation of intracellular proteins is a posttranslational modification that plays a regulatory role in signal transduction during cellular events.Dephosphorylation of signal transduction proteins caused by protein tyrosine phosphatases(PTPs)contributed their role as a convergent node to mediate cross-talk between signaling pathways.In the context of cancer,PTP-mediated pathways have been identified as signaling hubs that enabled cancer cells to mitigate stress induced by clinical therapy.This is achieved by the promotion of constitutive activation of growth-stimulatory signaling pathways or modulation of the immune-suppressive tumor microenvironment.Preclinical evidences suggested that anticancer drugs will release their greatest therapeutic potency when combined with PTP inhibitors,reversing drug resistance that was responsible for clinical failures during cancer therapy.Areas covered:This review aimed to elaborate recent insights that supported the involvement of PTP-mediated pathways in the development of resistance to targeted therapy and immune-checkpoint therapy.Expert opinion:This review proposed the notion of PTP inhibition in anticancer combination therapy as a potential strategy in clinic to achieve long-term tumor regression.Ongoing clinical trials are currently underway to assess the safety and efficacy of combination therapy in advanced-stage tumors.
基金The Scientific Research Foundation for the Returned Overseas Chinese Scholars(Grant No.20091590)State Education Ministry and Key Laboratory of Natural Resources of Changbai Mountain & Functional Molecules(Yanbian University),Ministry of Education,China(Grant No.201003)
文摘An organic layer prepared from the seed of Aceriphyllum rossii was studied to identify the active compounds for protein tyrosine phosphatase 1B（PTP1B） inhibition.Bioassay guided fractionation resulted in the isolation of PTP1B inhibitory activity of triterpenes（1-4）.These four compounds were identified as aceriphyllic acid C（1）,aceriphyllic acid D（2）,aceriphyllic acid E（3） and aceriphyllic acid F（4）.The isolated 1-4 compounds inhibited PTP1B with IC50 values ranged from（2.1±1.5） μmol/L to（11.2±2.5） μmol/L.Kinetic analysis of PTP1B inhibition by aceriphyllic acid C（1） and aceriphyllic acid D（2） suggested that oleanane-type triterpenes inhibited PTP1B activity in a mixed-type manner.
基金Science and Technology Development Program of Jilin Province(Grant No.20150101225JC)
文摘Seven oleanene triterpenes were isolated from the roots of Potentilla discolor Bge and their structures were identified as 3-oxoolean-12-en-27-oic acid（1）, gypsogenic acid（2）, 3α-hydroxyolean-12-en-27-oic acid（3）, 3β-hydroxyolean-12-en-27-oic acid（4）, aceriphyllic acid A（5）, aceriphyllic acid A methyl ester（6）, and oleanolic acid（7）. Compounds 1–7 inhibited protein tyrosine phosphatase 1B（PTP1B） activity, with IC50 values ranging from（7.5±0.5） to（22.7±0.5） μmol/L. Among the isolates, compounds 1, 2, 3 and 7 from the Potentilla discolor Bge were found to exhibit selective PTP1 B inhibitory activity.
基金Supported by Shandong Provincial Natural Science Foundation,China(No.ZR2012HQ004)the Research Fund for Fundamental Research Project of Qingdao(No.13-1-4-180-jch)+1 种基金the Scientific Research Fund of Huangdao District of Qingdao City(No.2014-1-74)the Young People Scientific Research Fund of Affiliated Hospital,Qingdao University(No.QDFY134)
文摘AIMTo evaluate whether protein tyrosine phosphatase 1B (PTP1B) contributed to initiate human retinal pigment epithelium cells (A)-19 migration and investigate the signaling pathways involved in this process.METHODSARPE-19 cells were cultured and treated with the siRNA-PTP1B. Expression of PTP1B was confirmed by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). AG1478 [a selective inhibitor of epidermal growth factor receptor (EGFR)] and PD98059 (a specific inhibitor of the activation of mitogen-activated protein kinase) were used to help to determine the PTP1B signaling mechanism. Western blot analysis verified expression of EGFR and extracellular signal-regulated kinase (ERK) in ARPE-19 cells. The effect of siRNA-PTP1B on cell differentiation was confirmed by immunostaining for α-smooth muscle actin (α-SMA) and qRT-PCR. Cell migration ability was analyzed by transwell chamber assay.RESULTSThe mRNA levels of PTP1B were reduced by siRNA-PTP1B as determined by qRT-PCR assay. SiRNA-PTP1B activated EGFR and ERK phosphorylation. α-SMA staining and qRT-PCR assay demonstrated that siRNA-PTP1B induced retinal pigment epithelium (RPE) cells to differentiate toward better contractility and motility. Transwell chamber assay proved that PTP1B inhibition improved migration activity of RPE cells. Treatment with AG1478 and PD98059 abolished siRNA-PTP1B-induced activation of EGFR and ERK, α-SMA expression and cell migration.CONCLUSIONPTP1B inhibition promoted myofibroblast differentiation and migration of ARPE-19 cells, and EGFR/ERK signaling pathway played important role in migration process.
基金the Fund of Science & Technology Bureau of Jilin Province, China(Nos.20060563, 200705394 and 20080434).
文摘This study is focused on the expression of an SH2 domain-truncated form of protein tyrosine phosphatase SHP-1（designated ΔSHP-1） and the preparation of its polyclonal antibodies. A cDNA fragment encoding ΔSHP-1 was amplified by PCR and then cloned into the pT7 expression vector. The recombinant pT7-ΔSHP-1 plasmid was used to transform Rosetta（DE3） E. coli cells. ΔSHP-1 was distributed in the exclusion body of E. coli cell extracts and was purified through a two-column chromatographic procedure. The purified enzyme exhibited an expected molecular weight on SDS-gels and HPLC gel filtration columns. It possesses robust tyrosine phosphatase activity and shows typical enzymatic characteristics of classic tyrosine phosphatases. To generate polyclonal anti-ΔSHP-1 antibodies, purified recombinant ΔSHP-1 was used to immunize a rabbit. The resultant anti-serum was subjected to purification on ΔSHP-1 antigen affinity chromatography. The purified polyclonal antibody displayed a high sensitivity and specificity toward ΔSHP-1. This study thus provides the essential materials for further investigating the biological function and pathological implication of SHP-1 and screening the inhibitors and activators of the enzyme for therapeutic drug development.
基金supported by the Research Foundation of Public Health Bureau of Hubei Province(No.JX3A14),China
文摘The protein tyrosine phosphatase 1B（PTP1B）is an important regulator of metabolism.The relationship between PTP1B and tumors is quite complex.The purpose of this study is to explore the expression pattern and role of PTP1B in breast cancer.The expression of PTP1B was detected in 67 samples of breast cancer tissue by Western blot.Cell growth assay,Transwell migration assay,and Scratch motility assay were used to examine the proliferation and migration of MCF-7 with and without PTP1B.The total levels and phosphorylated levels of signal transduction and activator of transcription 3（STAT3）and the expression of C-C motif chemokine ligand 5（CCL5）were also examined by Western blot.PTP1B was overexpressed in over 70%of breast cancer tissues,correlating with patients with estrogen receptor（ER）-negative,progesterone receptor（PR）-negative,and human epidermal growth factor receptor 2（HER2）-positive tumors.The data also showed that both tumor size and lymph node metastasis were significantly higher in patients with a higher level of PTP1B.The proliferation and migration of MCF-7 cells were found to be inhibited after knocking down the gene of PTP1B.Our data also showed that PTP1B could up-regulate the dephosphorylated level of STAT3,which could increase the expression of CCL5.These phenomena indicated that PTP1B may play a crucial role in the development of breast cancer.
文摘BACKGROUND The incidence of primary liver cancer is increasing year by year.In 2022 alone,more than 900000 people were diagnosed with liver cancer worldwide,with hepatocellular carcinoma(HCC)accounting for 75%-85%of cases.HCC is the most common primary liver cancer.China has the highest incidence and mortality rate of HCC in the world,and it is one of the malignant tumors that seriously threaten the health of Chinese people.The onset of liver cancer is occult,the early cases lack typical clinical symptoms,and most of the patients are already in the middle and late stage when diagnosed.Therefore,it is very important to find new markers for the early detection and diagnosis of liver cancer,improve the therapeutic effect,and improve the prognosis of patients.Protein tyrosine phosphatase non-receptor 2(PTPN2)has been shown to be associated with colorectal cancer,triple-negative breast cancer,non-small cell lung cancer,and prostate cancer,but its biological role and function in tumors remain to be further studied.AIM To combine the results of relevant data obtained from The Cancer Genome Atlas(TCGA)to provide the first in-depth analysis of the biological role of PTPN2 in HCC.METHODS The expression of PTPN2 in HCC was first analyzed based on the TCGA database,and the findings were then verified by immunohistochemical staining,quantitative real-time polymerase chain reaction(qRT-PCR),and immunoblotting.The value of PTPN2 in predicting the survival of patients with HCC was assessed by analyzing the relationship between PTPN2 expression in HCC tissues and clinicopathological features.Finally,the potential of PTPN2 affecting immune escape of liver cancer was evaluated by tumor immune dysfunction and exclusion and immunohistochemical staining.RESULTS The results of immunohistochemical staining,qRT-PCR,and immunoblotting in combination with TCGA database analysis showed that PTPN2 was highly expressed and associated with a poor prognosis in HCC patients.Kyoto Encyclopedia of Genes and Genomes enrichment analysis showed that PTPN2 was associated with various pathways,including cancer-related pathways,the Notch signaling pathway,and the MAPK signaling pathway.Gene Set Enrichment Analysis showed that PTPN2 was highly expressed in various immune-related pathways,such as the epithelial mesenchymal transition process.A risk model score based on PTPN2 showed that immune escape was significantly enhanced in the high-risk group compared with the low-risk group.CONCLUSION This study investigated PTPN2 from multiple biological perspectives,revealing that PTPN2 can function as a biomarker of poor prognosis and mediate immune evasion in HCC.
基金Supported by the Natural Science Foundation of Guangxi Province(Nos.2013GXNSFAA019019 and 2013GXNSFAA019041)
文摘Oleanolic acid derivatives act as newer protein tyrosine phosphatase 1B （PTP-1B） inhibitors for type 2 diabetes mellitus （T2DM）. In order to understand the structural requirement of PTP-1B inhibitors, 52 oleanolic acid derivatives were divided into a training set （34 compounds） and a test set （18 compounds）. The highly reliable and predictive 3D-QSAR models were constructed by CoMFA, CoMSIA and topomer CoMFA methods, respectively. The results showed that the cross validated coefficient （q2） and non-cross-validated coefficient （R2） were 0.554 and 0.999 in the CoMFA model, 0.675 and 0.971 in the CoMSIA model, and 0.628 and 0.939 in the topomer CoMFA model, which suggests that three models are robust and have good exterior predictive capabilities. Furthermore, ten novel inhibitors with much higher inhibitory potency were designed. Our design strategy was that （i） the electronegative substituents （Cl, -CH2OH, OH and -CH2Cl） were introduced into the double bond of ring C, （ii） the hydrogen bond acceptor groups （C≡N and N atom）, electronegative groups （C≡N, N atom, -COOH and -COOCH3） and bulky substituents （C6H5N） were connected to the C-3 position, which would result in generating potent and selective PTP-1B inhibitors. We expect that the results in this paper have the potential to facilitate the process of design and to develop new potent PTP-1B inhibitors.
基金Supported by the National Major Research Program of China"The Creation for Significant Innovative Drugs"(No.2009ZX09103-148)the Natural Science Foundation of Shandong(No.BS2009YY011)+1 种基金the Natural Science Foundation of Qingdao(No.10-3-4-8-2-JCH)the Program of Qingdao Shinan District(No.2009-HY-2-14)
文摘3-bromo-4,5-bis（2,3-dibromo-4,5-dihydroxybenzyl）-l,2-benzenediol （1） is a natural bromophenol isolated from the red algae Rhodomela confervoides that exhibits significant inhibition against protein tyrosine phosphatase 1B （PTP1B）. Based on its activity, we synthesized two new synthetic bromophenols and their methoxy derivatives from vanillin using the structure of natural bromophenol 1 as a scaffold. The structures of these bromophenols were elucidated from H NMR, 13C NMR, and high resolution electron ionization mass spectrometry as 2,3-dibromo-1-（2＇-bromo-6＇-（3＂,4＂-dimethoxybenzyl）- 3 ＇,4 ＇-dimethoxybenzyl）-4,5 -dimethoxybenzene （2）, 2,3-dibromo- 1 -（2 ＇-bromo-6＇-（2 ＂-bromo-4＂,5 ＂-dimethoxy- benzyl）-3＇,4＇-dimethoxybenzyl）-4,5-dimethoxybenzene （3）, 3,4-dibromo-5-（2＇-bromo-6＇-（2＂-bromo-4＂,5＂- dihydroxybenzyl）-3＇,4＇-dihydroxybenzyl）pyrocatechol （4） and 3,4-dibromo-5-（2＇-bromo-6＇-（3＂,4＂- dihydroxybenzyl）-3＇,4＇-dihydroxybenzyl）pyrocatechol （5）. PTP1B inhibition activities of these compounds were evaluated using a colorimetric assay, and compounds 3 and 4 demonstrated interesting activity against PTP1B.
基金Supported by the National Natural Science Foundation of China(81072450)
文摘Objective To study the expression level of peptidylarginine deiminase 4(PADI4) and protein tyrosine phosphatase nonreceptor type 22(PTPN22) in the synovium of rat model of collagen-induced arthritis, and to explore their possible therapeutic role in rheumatoid arthritis. Methods Thirty-two female Wistar rats weighing 100±20 g were randomly assigned into 3-week collagen-induced arthritis(CIA) model group(n=8), 4-week CIA model group(n=8), 6-week CIA model group(n=8), and the control group(n=8). The body weight changes of each group were recorded. The expression levels of PADI4 and PTPN22 were detected and compared by the methods of immunohistochemical staining and Western blot. Results Arthritis of rat began to form 14 days after sensitization and the joint swelling reached peak at 28 days. The weights of the rats slowly grew both in CIA model groups and the control group. Immunohistochemical staining results showed that the positive expression of PADI4 and PTPN22 was mainly located in cartilage peripheral mononuclear cells, the cytoplasm of infiltrated cells, and bone marrow cavity. There were significant differences in the optical density of PADI4 and PTPN22 among CIA model groups and the control group(PADI4, 0.2898±0.012, 0.2982±0.022, 0.2974±0.031, 0.2530±0.013 in 3-week CIA model, 4-week CIA model, 6-week CIA model and control groups; PTPN22, 0.2723±0.004, 0.2781±0.010, 0.2767±0.008, 0.2422±0.019; all P <0.05). The expression bands of PADI4 were observed in Western blot 3 weeks after initial immunization, the thickest in the 4th week, and decreased in the 6th week. The expression bands of PTPN2 were observed at all the time points, with no obvious time-dependent trend. Conclusions PADI4 and PTPN22 are obviously correlated with CIA in rat model. PADI4 is expressed at early stage of the disease, while the expression of PTPN22 sustains throughout the course.
基金Supported by the Fund of Science and Technology Department of Jilin Province(No20060563)in part by the Fund of Scienceand Technology Department of Jilin Province(No200505120) the Bureau of Science and Technology of Changchun City(No06GG110)
文摘This study objective was to express and characterize the catalytic domain of the human T cell protein tyrosine phosphatase（△TC-PTP） and to study immunohistochemically the expression of △TC-PTP in human non-small cell lung cancers. △TC-PTP gene was PCR amplified with the cDNA of human TC-PTP as template, and cloned into the pT7 expression vector. The recombinant pT7-△TC-PTP was expressed in E. coli Rosetta （ DE3 ） host cells and puri- fied. The enzymatic characteristics of △TC-PTP including enzyme activity and kinetics assay were measured. The antiserum was prepared by immunizing rabbit with the purified recombinant △TC-PTP. Rabbit polyclonal antibody against △TC-PTP was purified by PVDF immobilized antigen affinity chromatography. Immunohistochemical staining of lung cancer tissues was performed with antibody against △TC-PTP protein. △TC-PTP gene was correctly cloned, expressed, and purified. The recombinant △TC-PTP had a highly catalytic activity of PTPase. Squamous cell lung carcinoma showed a significantly higher expression rate of △TC-PTP （76. 92%, 10/13 ） than adenocarcinoma （57.14%, 4/7） and normal lung tissue（20%, 1/5 ）. This study represents the first demonstration that △TC-PTP is highly expressed in human squamous cell lung carcinomas. In addition, this study provides an important basis for further studying the biological function of TC-PTP and its relationship with lung carcinomas and other diseases.
基金Supported by the Plan of Development for Science & Technology of Jilin Province,China(No.20090920)
文摘PTPMEGI is an intracellular protein tyrosine phosphatase（PTP）, which contains FERM and PDZ domains This study focuses our attention on the expression, purification and characterization of catalytic domain of PTPMEG1 （AMEG1） and preparation of its polyclonal antibody. A cDNA fragment encoding AMEG1 protein（amino acid residues 643-926） was amplified by PCR and then cloned into the pT7-7 vector. Both soluble and insoluble recombinant AMEG1 proteins were observed after induction by IPTG. Soluble AMEG1 was purified via two chromatographic steps, and the purified enzyme was characterized. With para-nitrophenylphosphate（pNPP） as a substrate, AMEG1 exhibited typical enzymatic characteristics of classic PTPs and classical Michaelis-Menten kinetics. Insoluble AMEG1, which was mainly distributed in the inclusion body of E. coli cells extracts, was purified by preparative electrophoresis gel for the preparation of the polyclonal antibody. A rabbit was immunized with AMEG1 purified by preparative electrophoresis to generate anti-AMEG1 antibody. Anti-serum was collected on 28th day after initial injection and purified via affinity chromatography. The purified polyconal antibody displayed a satisfactory titer and sensitivity.
基金funded by Higher Education commission,Pakistan(HEC),Grant No.NRPU649.
文摘Proteintyrosine phosphatase 1B(PTP1B)inhibitionis consideredas a potentialtherapeuticfor the treatmentof cancer,type2 diabetes,andobesity.Inour presentwork,weinvestigatedtheanti-diabeticpotentialof8-hydroxydiospyrin(8-HDN)from D.lotus against the PTP1B enzyme.It showed significant inhibitory activity of PTP1B with an IC 50 value of 18.37±0.02μM.A detailed molecular docking study was carried out to analyze the binding orientation,binding energy,and mechanism of inhibition.A comparative investigation of 8-HDN in the catalytic,as well as the allosteric site of PTP1B,was performed.Binding energy data showed that compound 8-HDN is more selective for the allosteric site and hence avoids the problems associated with catalytic site inhibition.The inhibition mechanism of 8-HDN can be further investigated as an active lead compound against PTP1B by using in vitro and in vivo models.
基金the Scientific Innovation Foundation of Jilin University for Undergraduates(No.2007CX02)
文摘A DNA fragment encoding the intracellular part of tyrosine phosphatase RPTPα designated as RPTPα-2D gene was amplified by PCR from a human prostate cDNA library and cloned into the pT7 E. coli expression vector. The resulting plasmid pT7-RPTPα-2D was used to transform Rosetta DE3 E. coli cells. RPTPα-2D was predominately expressed in the insoluble inclusion body and was effectively purified using preparative electrophoresis gels. Polyclonal antibodies were obtained after immunization of a rabbit with purified RPTPα-2D. The antibodies displayed a high titer and sensitivity. This study thus provided a valuable tool for further researches on RPTPα.
基金the Science and Technology Department of Jilin Province(No 20060563)
文摘This study focuses on the expression of human protein tyrosine phosphatase 1B （PTP1 B） catalytic domain （△PTP1B） and preparation of polyclonal antibody against △PTP1B. △PTP1B gene was PCR amplified with the cDNA of human PTP1B as the template, and cloned into the pT7 expression vector. The recombinant pT7-△PTP1B was expressed in E. eoli Rosetta（ DE3 ） host cells and purified. The antiserum was prepared by immunizing rabhit with purified recombinant △PTP1B. The polyclonal antibody against △PTP1B was purified by PVDF immobilized antigen affinity chromatography. △PTP1B was correctly cloned, expressed, and purified as confirmed by PCR, DNA sequence analysis, SDS-PAGE western blotting, and ILPLC. The titer and sensitivity of the antibody were 1：2500（ volume ratio） and 0. 1 ng, respectively. This study provides an important basis for further studying the biological function of PTP1B and its relationship with human diseases.
基金supported by the Key Project of Natural Science Foundation of Guangdong Province of China(No.2017B030311010)Science and Technology Program of Guangzhou,China(No.202002030088)
文摘Background Long QT syndrome(LQTS)is a potentially fatal cardiac ion channel disease.Mutations in the gene encoding cardiac hERG potassium channel are the second most common causes of LQTS.Cardiac hERG potassium channel conducts the rapidly activating delayed rectifier potassium current(Ikr),which is one of the crucial currents in rapid repolarization phase of action potential in human cardiomyocytes.Function of hERG potassium channel is regulated by a variety of signaling pathways,in which phosphorylation and dephosphorylation of tyrosine proteins plays a major role.Previous research has found that non-receptor protein tyrosine phosphatase(PTPN)can interact with hERG potassium channel in cardiac cells.The aims of the present study were to investigate the regulatory effect of protein tyrosine phosphatase non-receptor type 12,11 and 6(PTPN12,PTPN11 and PTPN6)on cardiac hERG potassium channels.Methods HEK-293 cells were transfected with pcDNA3.0-hERG by Lipofectamine 2000 and selected by G418.HEK-293/hERG cells stably expressing hERG protein were then transfected with pcDNA3.1-PTPN12-RFP,pcDNA3.1-PTPN11-EGFP and pcDNA3.1-PTPN6-EGFP,respectively.Forty-eight hours after transfection,immunofluorescence assay and western blot were performed to detect the expression of hERG channel proteins and PTPN proteins.hERG channel currents in hERG alone-expressing group,PTPN12-,PTPN11-and PTPN6-overexpressing groups,as well as inhibitor groups were recorded by patch clamp technique.Results The maximum pulse current densities of PTPN12-,PTPN11-and PTPN6-overexpressing groups were all decreased when compared with hERG alone-expressing group(P<0.05).However,the maximum pulse current densities of inhibitor groups were all increased when compared with PTPN12-,PTPN11-and PTPN6-overexpressing groups,respectively(P<0.05).Conclusions Overexpression of PTPN12,PTPN11 and PTPN6 reduced the current density of hERG potassium channel,while this effect could be reversed by tyrosine phosphatase inhibitors.These results suggested that PTPN12,PTPN11 and PTPN6 negatively regulated hERG potassium channel currents by catalyzing the dephosphorylation process of hERG potassium channels.[S Chin J Cardiol 2021;22(1):38-49]
