MicroRNA-298 determines the radio-resistance of colorectal cancer cells by directly targeting human dual-specificity tyrosine(Y)-regulated kinase 1A

BACKGROUND Radiotherapy stands as a promising therapeutic modality for colorectal cancer(CRC);yet,the formidable challenge posed by radio-resistance significantly undermines its efficacy in achieving CRC remission.AIM To elucidate the role played by microRNA-298(miR-298)in CRC radio-resistance.METHODS To establish a radio-resistant CRC cell line,HT-29 cells underwent exposure to 5 gray ionizing radiation that was followed by a 7-d recovery period.The quantification of miR-298 levels within CRC cells was conducted through quantitative RT-PCR,and protein expression determination was realized through Western blotting.Cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and proliferation by clonogenic assay.Radio-induced apoptosis was discerned through flow cytometry analysis.RESULTS We observed a marked upregulation of miR-298 in radio-resistant CRC cells.MiR-298 emerged as a key determinant of cell survival following radiation exposure,as its overexpression led to a notable reduction in radiation-induced apoptosis.Intriguingly,miR-298 expression exhibited a strong correlation with CRC cell viability.Further investigation unveiled human dual-specificity tyrosine(Y)-regulated kinase 1A(DYRK1A)as miR-298’s direct target.CONCLUSION Taken together,our findings underline the role played by miR-298 in bolstering radio-resistance in CRC cells by means of DYRK1A downregulation,thereby positioning miR-298 as a promising candidate for mitigating radioresistance in CRC.

Mitogen-activated protein kinase phosphatase 1 protects PC12 cells from amyloid beta-induced neurotoxicity

The mitogen-activated protein kinase（MAPK） signaling pathway plays an important role in the regulation of cell growth, proliferation, differentiation, transformation and death. Mitogen-activated protein kinase phosphatase 1（MKP1） has an inhibitory effect on the p38 MAPK and JNK pathways, but it is unknown whether it plays a role in Aβ-induced oxidative stress and neuronal inflammation. In this study, PC12 cells were infected with MKP1 sh RNA, MKP1 lentivirus or control lentivirus for 12 hours, and then treated with 0.1, 1, 10 or 100 μM amyloid beta 42（Aβ42）. The cell survival rate was measured using the cell counting kit-8 assay. MKP1, tumor necrosis factor-alpha（TNF-α） and interleukin-1β（IL-1β） m RNA expression levels were analyzed using quantitative real time-polymerase chain reaction. MKP1 and phospho-c-Jun N-terminal kinase（JNK） expression levels were assessed using western blot assay. Reactive oxygen species（ROS） levels were detected using 2′,7′-dichlorofluorescein diacetate. Mitochondrial membrane potential was measured using flow cytometry. Superoxide dismutase activity and malondialdehyde levels were evaluated using the colorimetric method. Lactate dehydrogenase activity was measured using a microplate reader. Caspase-3 expression levels were assessed by enzyme-linked immunosorbent assay. Apoptosis was evaluated using the terminal deoxynucleotidyl transferase d UTP nick end labeling method. MKP1 overexpression inhibited Aβ-induced JNK phosphorylation and the increase in ROS levels. It also suppressed the Aβ-induced increase in TNF-α and IL-1β levels as well as apoptosis in PC12 cells. In contrast, MKP1 knockdown by RNA interference aggravated Aβ-induced oxidative stress, inflammation and cell damage in PC12 cells. Furthermore, the JNK-specific inhibitor SP600125 abolished this effect of MKP1 knockdown on Aβ-induced neurotoxicity. Collectively, these results show that MKP1 mitigates Aβ-induced apoptosis, oxidative stress and neuroinflammation by inhibiting the JNK signaling pathway, thereby playing a neuroprotective role.

Purification and Characterization of the Catalytic Domain of Protein Tyrosine Phosphatase SHP-1 and the Preparation of Anti-ΔSHP-1 Antibodies

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.

Protein tyrosine phosphatase 1B regulates migration of ARPE-19 cells through EGFR/ERK signaling pathway

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.

Overexpression of mitogen-activated protein kinase phosphatase-1 in endothelial cells reduces blood-brain barrier injury in a mouse model of ischemic stroke

Ischemic stroke can cause blood-brain barrier(BBB)injury,which worsens brain damage induced by stroke.Abnormal expression of tight junction proteins in endothelial cells(ECs)can increase intracellular space and BBB leakage.Selective inhibition of mitogen-activated protein kinase,the negative regulatory substrate of mitogen-activated protein kinase phosphatase(MKP)-1,improves tight junction protein function in ECs,and genetic deletion of MKP-1 aggravates ischemic brain injury.However,whether the latter affects BBB integrity,and the cell type-specific mechanism underlying this process,remain unclear.In this study,we established an adult male mouse model of ischemic stroke by occluding the middle cerebral artery for 60 minutes and overexpressed MKP-1 in ECs on the injured side via lentiviral transfection before stroke.We found that overexpression of MKP-1 in ECs reduced infarct volume,reduced the level of inflammatory factors interleukin-1β,interleukin-6,and chemokine C-C motif ligand-2,inhibited vascular injury,and promoted the recovery of sensorimotor and memory/cognitive function.Overexpression of MKP-1 in ECs also inhibited the activation of cerebral ischemia-induced extracellular signal-regulated kinase(ERK)1/2 and the downregulation of occludin expression.Finally,to investigate the mechanism by which MKP-1 exerted these functions in ECs,we established an ischemic stroke model in vitro by depriving the primary endothelial cell of oxygen and glucose,and pharmacologically inhibited the activity of MKP-1 and ERK1/2.Our findings suggest that MKP-1 inhibition aggravates oxygen and glucose deprivation-induced cell death,cell monolayer leakage,and downregulation of occludin expression,and that inhibiting ERK1/2 can reverse these effects.In addition,co-inhibition of MKP-1 and ERK1/2 exhibited similar effects to inhibition of ERK1/2.These findings suggest that overexpression of MKP-1 in ECs can prevent ischemia-induced occludin downregulation and cell death via deactivating ERK1/2,thereby protecting the integrity of BBB,alleviating brain injury,and improving post-stroke prognosis.

Structural Insight into the Design on Oleanolic Acid Derivatives as Potent Protein Tyrosine Phosphatase 1B Inhibitors

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.

Synthesis and protein tyrosine phosphatase 1B inhibition activities of two new synthetic bromophenols and their methoxy derivatives

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.

Purification and Characterization of Protein Tyrosine Phosphatase MEG1 and Preparation of Anti-PTPMEG1 Antibody

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.

Regulation of Ikaros function by casein kinase 2 and protein phosphatase 1

The Ikaros gene encodes a zinc finger,DNA-binding protein that regulates gene transcription and chromatin remodeling.Ikaros is a master regulator of hematopoiesis and an established tumor suppressor.Moderate alteration of Ikaros activity (e.g.haploinsufficiency) appears to be sufficient to promote malignant transformation in human hematopoietic cells.This raises questions about the mechanisms that normally regulate Ikaros function and the potential of these mechanisms to contribute to the development of leukemia.The focus of this review is the regulation of Ikaros function by phosphorylation/dephosphorylation.Site-specific phosphorylation of Ikaros by casein kinase 2 (CK2) controls Ikaros DNA-binding ability and subcellular localization.As a consequence,the ability of Ikaros to regulate cell cycle progression,chromatin remodeling,target gene expression,and thymocyte differentiation are controlled by CK2.In addition,hyperphosphorylation of Ikaros by CK2 leads to decreased Ikaros levels due to ubiquitinmediated degradation.Dephosphorylation of Ikaros by protein phosphatase 1 (PP1) acts in opposition to CK2 to increase Ikaros stability and restore Ikaros DNA binding ability and pericentromeric localization.Thus,the CK2 and PP1 pathways act in concert to regulate Ikaros activity in hematopoiesis and as a tumor suppressor.This highlights the importance of these signal transduction pathways as potential mediators of leukemogenesis via their role in regulating the activities of Ikaros.

A novel protein tyrosine phosphatase 1B inhibitor with therapeutic potential for insulin resistance

Insulin sensitizing medicines are currently limited, and identification of new drug candidate is a chal- lenge. Protein tyrosine phosphatase 1B （PTP1 B） negatively regulates insulin signaling pathway, and its inhibition is anticipated to improve insulin resistance. This study investigated the pharmacological profiles of compound CX08005, a new PTP1B inhibitor, with therapeutic potential for insulin resistance in vivo and in vitro, respective- ly. Recombinant human PTP1B protein was used to measure the enzyme activity. The docking simulation was per- formed to explore the interactions between the compound and the protein. The insulin sensitivity was evaluated in Diet-induced obesity mice and/or T2DM KKAy mice by glucose tolerance test （GTT）, the blood glucose level, glucose stimulated insulin secretion （GSIS）, homeostasis model assessment of insulin resistance index （HOMA-IR） and the whole-body insulin sensitivity （ISwb） index, respectively. The hyperinsulinemic-euglycemic clamp was performed to evaluate the insulin stimulated glucose disposal both in whole body and in insulin-sensitive tissues （muscle and fat）. Furthermore, its direct effect in muscle, fat and liver cells was observed. We found that CX08005 was a competitive inhibitor of PTP1B with dose-dependent activity （IC50=5.95 × 10^-7 M）. Docking simulation demonstrated that CX08005 binds to PTP1B at the catalytic P-loop through hydrogen bonds. In DIO mice, treatment with CX08005 effectively ameliorated glucose intolerance in a dose-dependent manner （50- 200 mg. kg^-1 · d^-l）, and decreased HOMA-IR values. We also demonstrated that oral administration of 50 mg ~ kg^-1· d^-1 CX08005 improved hyperglycemia, hyperinsulinemia, HOMA-IR and ISwb in KKAy mice. In hyperin- sulinemic-euglycemic clamp test, CX08005 increased glucose infusion rate and glucose uptake in muscle and fat of DIO mice. In 3T3-L1 adipocytes and C2C12 myotubes, CX08005 enhanced insulin-induced glucose uptake. In HepG2 hepatocyte, CX08005 enhanced insulin-stimulated tyrosine phosphorylation of IRβ/IRS1 in a dose-depend- ent manner, respectively; furthermore, the phosphorylation of several downstream molecules, including Akt, Foxol and GSK3β was also increased, indicating this compound could augment insulin＇s ability to suppress hepatic glu- cose output （HGO）. Our results strongly suggest that compound CX08005 directly enhances insulin action in vitro and in vivo with therapeutic potential for insulin resistance.

POM analysis and computational interactions of 8-hydroxydiospyrin inside active site of protein tyrosine phosphatase 1B

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.

A role for mitogen-activated protein kinase phosphatase 1(MKP1) in neural cell development and survival

The mitogen-activated protein kinase（MAPK）pathways are a group of conserved intracellular signalling pathways present in most cells including neurons and glia.These pathways respond to a variety of stimuli including growth factors,cytokines and oxidative stress to generate appropriate cellular responses such as modulation of gene expression,cell proliferation,differentiation and survival as well as the stress response（Korhonen and Moilanen,2014）.

Phosphoprotein phosphatase 1-interacting proteins as therapeutic targets in prostate cancer

Prostate cancer is a major public health concern world-wide, being one of the most prevalent cancers in men. Great improvements have been made both in terms of early diagnosis and therapeutics. However, there is still an urgent need for reliable biomarkers that could overcome the lack of cancer-specifcity of prostate-specifc antigen, as well as alternative therapeutic targets for advanced metastatic cases. Reversible phosphorylation of proteins is a post-translational modifcation critical to the regulation of numerous cellular processes. Phosphoprotein phosphatase 1 （PPP1） is a major serine/threonine phos-phatase, whose specifcity is determined by its interacting proteins. These interactors can be PPP1 substrates, regulators, or even both. Deregulation of this protein-protein interaction network alters cell dynamics and underlies the development of several cancer hallmarks. Therefore, the identification of PPP1 interactome in specific cellular context is of crucial importance. The knowledge on PPP1 complexes in prostate cancer remains scarce, with only 4 holoenzymes characterized in human prostate cancer models. However, an increasing number of PPP1 interactors have been identifed as expressed in human prostate tissue, including the tumor suppressors TP53 and RB1. Efforts should be made in order to identify the role of such proteins in prostate carcinogenesis, since only 26 have yet well-recognized roles. Here, we revise literature and human protein databases to provide an in-depth knowledge on the biological significance of PPP1 complexes in human prostate carcinogenesis and their potential use as therapeutic targets for the development of new therapies for prostate cancer.

Inactivation of Protein Tyrosine Phosphatase 1B （PTP1B） Activity by the Aqueous Partition of Guava Leaf Extract

Guava leaf tea has been used as a folk medicine for treating hyperglycemic conditions in Asia and Africa. The hypoglycemic efficacy of guava leaf has been documented by many scientists in these regions, but the hypoglycemic mechanism is poorly understood. Guava leaves were extracted with methanol and the crude extract was partitioned against hexane, ethyl acetate, and butanol in sequence. The leftover in water is defined as the aqueous partition. A second smaller batch was extracted with hot water directly. Oral glucose tolerance test was carried out on healthy mice instead of diabetic mice that lack endogenous insulin. Glucose uptake was examined with 3T3-L1 adipocytes. Oxidative effect on PTP1B （protein tyrosine phosphatase 1b） was carried out with real-time PTP1B enzymatic assay. The aqueous partition of guava leaf extract possesses a potent inhibitory effect on PTP1B enzymatic activity and this PTP1B inhibition is through a slow oxidative but reversible inactivation on the enzyme. The reversible inactivation would suggest guava leaf extract may augment PTP1B inhibition alongside the endogenous H2O2 which itself is induced by insulin. In addition, our study confirmed the hypoglycemic efficacy being associated with guava leaf and found the most effective molecules reside in the aqueous partition which is also less cytotoxic to Chinese hamster ovary cells when compared to other less polar partitions. The guava leaf extract can modulate insulin activity through a redox regulation on PP1B enzymatic activity. It is speculated that a compound similar to gallocatechin in the aqueous partition can reduce an oxygen molecule to hydrogen peroxide which in turn oxidizes the catalytic residue Cys in PTP1B. Therefore, the guava leaf tea can serve as a functional hypoglycemic drink that is suitable for either healthy or diabetic subjects.

Phosphoprotein Phosphatase 1 Isoforms Alpha and Gamma Respond Differently to Prodigiosin Treatment and Present Alternative Kinase Targets in Melanoma Cells

Reversible protein phosphorylation is a central regulatory mechanism of cell function. Deregulation of the balanced actions of protein kinases and phosphatases has been frequently associated with several pathological conditions, including cancer. Many studies have already addressed the role of protein kinases misregulation in cancer. However, much less is known about protein phosphatases influence. Phosphoprotein Phosphatase 1 (PPP1) is one of the major serine/threonine protein phosphatases who has three catalytic isoforms: PPP1CA, PPP1CB, and PPP1CC. Its function is achieved by binding to regulatory subunits, known as PPP1-interacting proteins (PIPs), which may prefer a catalytic isoform. Also, some inhibitors/enhancers may exhibit isoform specificity. Here we show that, prodigiosin (PG), a molecule with anticancer properties, promotes the formation of PPP1CA-AKT complex and not of PPP1CC-MAPK complex. Both, AKT and MAPK, are well-known PIPs from two pathways that crosstalk and regulate melanoma cells survival. In addition, the analysis performed using surface plasmon resonance (SPR) technology indicates that PPP1 interacts with obatoclax (OBX), a drug that belongs to the same family of PG. Overall, these results suggest that PG might, at least in part, act through PPP1C/PIPs. Also, this study is pioneer in demonstrating PPP1 isoform-specific modulation by small molecules.

Phosphatase and tensin homology deleted in chromosome 10,hypoxia-inducible factor-1 alpha gene expression in colorectal adenoma and adenocarcinoma and their relation to vascular endothelial growth factor protein expression

To examine phosphatase and tensin homology deleted in chromosome 10 (PTEN),hypoxia-inducible factor-1 alpha (HIF-1 alpha) gene expressions and their relation to vascular endothelial growth factor(VEGF) protein expression in the patients with human colorectal adenomas and adenocarcinomas.Methods The expression of PTEN,HIF-1 alpha gene was detected by using in situ hybridization,and the VEGF expression levels by immunohistochemistry in colorectal adenomas and primary colorectal adenocarcinoma.Results Strong expression of HIF-1 alpha was detectable in the majority of colorectal dadenocarcinoma,particularly surrounding areas of necrosis in adenocarcinoma.PTEN,HIF-1 alpha mRNA and VEGF protein were positive in 51.6%,67.7% and 59.7% respectively in 62 cases of adenocarcinomas,and 77.8%,44.4% and 33.3% respectively in 18 cases of adenomas.The positive rate of VEGF was higher in the patients with colorectal adenocarcinomas than that in those with adenomas,whereas that of PTEN mRNA was contrary.HIF-1 mRNA expression was correlated significantly with lymph node metastasis,liver metastasis,Duke’s stage and recurrence.During colorectal tumor progression,the expression of HIF-1 alpha mRNA was positively correlated with the VEGF protein expression (χ2= 4.751 ,P<0.05),but negatively with the PTEN mRNA expression(χ2=21.84,P<0.01).Conclusion The absence or low expression of PTEN and the increased levels of HIF-1α and VEGF may paly an important role in carcinogenesis and progression of colorectal carcinoma.These results suggest that VEGF upregulated by HIF-1 alpha gene may be involved in angiogenesis of colorectal adenocarcinoma.4 refs,1 tab.

Counter-regulatory phosphatases TNAP and NPP1 temporally regulate tooth root cementogenesis

Cementum is critical for anchoring the insertion of periodontal ligament fibers to the tooth root. Several aspects of cementogenesis remain unclear, including differences between acellular cementum and cellular cementum, and between cementum and bone. Biomineralization is regulated by the ratio of inorganic phosphate （Pi） to mineral inhibitor pyrophosphate （PPi）, where local Pi and PPi concentrations are controlled by phosphatases including tissue-nonspecific alkaline phosphatase （TNAP） and ectonucleotide pyrophosphatase/phosphodiesterase 1 （NPP1）. The focus of this study was to define the roles of these phosphatases in cementogenesis. TNAP was associated with earliest cementoblasts near forming acellular and cellular cementum. With loss of TNAP in the Alpl null mouse, acellular cementum was inhibited, while cellular cementum production increased, albeit as hypomineralized cementoid. In contrast, NPP1 was detected in cementoblasts after acellular cementum formation, and at low levels around cellular cementum. Loss of NPP1 in the Enppl null mouse increased acellular cementum, with little effect on cellular cementum. Developmental patterns were recapitulated in a mouse model for acellular cementum regeneration, with early TNAP expression and later NPP1 expression. In vitro, cementoblasts expressed Alpl gene/protein early, whereas Enppl gene/protein expression was significantly induced only under mineralization conditions. These patterns were confirmed in human teeth, including widespread TNAP, and NPP1 restricted to cementoblasts lining acellular cementum. These studies suggest that early TNAP expression creates a low PPi environment promoting acellular cementum initiation, while later NPP1 expression increases PPi, restricting acellular cementum apposition. Alterations in PPi have little effect on cellular cementum formation, though matrix mineralization is affected.

Functional repertoire of protein kinases and phosphatases in synaptic plasticity and associated neurological disorders

Protein phosphorylation and dephosphorylation are two essential and vital cellular mechanisms that regulate many receptors and enzymes through kinases and phosphatases.Ca^2+- dependent kinases and phosphatases are responsible for controlling neuronal processing;balance is achieved through opposition.During molecular mechanisms of learning and memory,kinases generally modulate positively while phosphatases modulate negatively.This review outlines some of the critical physiological and structural aspects of kinases and phosphatases involved in maintaining postsynaptic structural plasticity.It also explores the link between neuronal disorders and the deregulation of phosphatases and kinases.

Dual-specificity Phosphatase 1 Deficiency Induces Endometrioid Adenocarcinoma Progression via Activation of Mitogen-activated Protein Kinase/Extracellular Signal-regulated Kinase Pathway

Background： Previously, we reported that dual-specificity adenocarcinoma （EEA）. However, the role of DUSP1 medroxyprogesterone （MPA） are still unclear. phosphatase I （DUSPI） was differentially expressed in endometrioid in EEA progression and the relationship between DUSPI and Methods： The expression of DUSPI in EEA specimens was detected by immunohistochemical analysis. The effect of DUSPI on cell proliferation was analyzed by Cell Counting Kit 8 and colony formation assay, and cell migration was analyzed by transwell assay. MPA-induced DUSPI expression in EEA cells was measured by Western blot. Results： DUSPI expression was deficient in advanced International Federation of Gynecology and Obstetrics stage, high-grade and myometrial invasive EEA. In EEA cell lines （HeclA, Hecl B, RL952, and Ishikawa）, the DUSP1 expression was substantially higher in lshikawa cells than in other cell lines （P 〈 0.05）. Knockdown ofDUSP I promoted lshikawa cells proliferation, migration, and activation of mitogen-activated protein kinases/extracellular signal-regulated kinase （MAPK/Erk） pathway. MPA-induced DUSP1 expression and inhibited MAPK/Erk pathway in Ishikawa cells. Conclusions： Our data suggest that DUSP1 deficiency promotes EEA progression via MAPK/Erk pathway, which may be reversed by MPA, suggesting that DUSP I may serve as a potential therapeutic target for the treatment of EEA.

醋酸去氨加压素对丝裂原活化蛋白激酶磷酸酶-1在大鼠耳蜗的表达及功能研究

目的检测醋酸去氨加压素(deamino arginine vasopressin,DDAVP)作用后丝裂原活化蛋白激酶磷酸酶-1(mitogen-activated protein kinase phosphatase,MKP-1)在大鼠耳蜗组织的表达情况,探讨MKP-1是否参与梅尼埃病的发生。方法选取SPF级雄性SD大鼠20只,随机分为实验组和对照组,每组10只。实验组腹腔注射DDAVP,对照组腹腔注射等量0.9%氯化钠溶液。造模结束后行听性脑干反应(auditory brainstem response,ABR)检测听力,苏木精-伊红染色观察耳蜗形态变化,免疫组织化学及蛋白质免疫印迹检测MKP-1在耳蜗的表达位置及定量分析。结果实验组ABR阈值较造模前上升约10 dB,差异有统计学意义(P<0.01);实验组耳蜗切片苏木精-伊红染色出现膜迷路积水表现,实验组积水率达80%;免疫组织化学显示,MKP-1广泛表达于血管纹、螺旋韧带、螺旋缘、柯蒂器、以及螺旋神经节。两组血管纹、螺旋韧带及螺旋神经节表达比较,差异均有统计学意义(P<0.05);两组SLM和OC表达比较,差异无统计学意义(P>0.05)。蛋白质免疫印迹显示,实验组MKP-1表达低于对照组,差异有统计学意义(P<0.01)。结论DDAVP可能通过下调MKP-1促进膜迷路积水形成,进而参与梅尼埃病的发病过程。