Receptor tyrosine kinase-like orphan receptor 1:A novel antitumor target in gastrointestinal cancers

Receptor tyrosine kinase-like orphan receptor 1(ROR1)is a member of the type I receptor tyrosine kinase family.ROR1 is pivotal in embryonic development and cancer,and serves as a biomarker and therapeutic target.It has soluble and membrane-bound subtypes,with the latter highly expressed in tumors.ROR1 is conserved throughout evolution and may play a role in the development of gastrointestinal cancer through multiple signaling pathways and molecular mechanisms.Studies suggest that overexpression of ROR1 may increase tumor invasiveness and metastasis.Additionally,ROR1 may regulate the cell cycle,stem cell characteristics,and interact with other signaling pathways to affect cancer progression.This review explores the structure,expression and role of ROR1 in the development of gastrointestinal cancers.It discusses current antitumor strategies,outlining challenges and prospects for treatment.

KAT7/HMGN1 signaling epigenetically induces tyrosine phosphorylation-regulated kinase 1A expression to ameliorate insulin resistance in Alzheimer’s disease

BACKGROUND Epidemiological studies have revealed a correlation between Alzheimer’s disease(AD)and type 2 diabetes mellitus(T2D).Insulin resistance in the brain is a common feature in patients with T2D and AD.KAT7 is a histone acetyltransferase that participates in the modulation of various genes.AIM To determine the effects of KAT7 on insulin patients with AD.METHODS APPswe/PS1-dE9 double-transgenic and db/db mice were used to mimic AD and diabetes,respectively.An in vitro model of AD was established by Aβstimulation.Insulin resistance was induced by chronic stimulation with high insulin levels.The expression of microtubule-associated protein 2(MAP2)was assessed using immunofluorescence.The protein levels of MAP2,Aβ,dual-specificity tyrosine phosphorylation-regulated kinase-1A(DYRK1A),IRS-1,p-AKT,total AKT,p-GSK3β,total GSK3β,DYRK1A,and KAT7 were measured via western blotting.Accumulation of reactive oxygen species(ROS),malondialdehyde(MDA),and SOD activity was measured to determine cellular oxidative stress.Flow cytometry and CCK-8 assay were performed to evaluate neuronal cell death and proliferation,respectively.Relative RNA levels of KAT7 and DYRK1A were examined using quantitative PCR.A chromatin immunoprecipitation assay was conducted to detect H3K14ac in DYRK1A.RESULTS KAT7 expression was suppressed in the AD mice.Overexpression of KAT7 decreased Aβaccumulation and MAP2 expression in AD brains.KAT7 overexpression decreased ROS and MDA levels,elevated SOD activity in brain tissues and neurons,and simultaneously suppressed neuronal apoptosis.KAT7 upregulated levels of p-AKT and p-GSK3βto alleviate insulin resistance,along with elevated expression of DYRK1A.KAT7 depletion suppressed DYRK1A expression and impaired H3K14ac of DYRK1A.HMGN1 overexpression recovered DYRK1A levels and reversed insulin resistance caused by KAT7 depletion.CONCLUSION We determined that KAT7 overexpression recovered insulin sensitivity in AD by recruiting HMGN1 to enhance DYRK1A acetylation.Our findings suggest that KAT7 is a novel and promising therapeutic target for the resistance in AD.

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.

血管生成素-1激活tyrosine kinase／PI3K增加血管内皮细胞[Mg^2＋]i

目的:探讨血管生成素-1(Ang-1)对人脐静脉内皮细胞(HUVECs)内游离镁离子浓度([Mg2+]i)的调节机制。方法:我们采用荧光指示剂mag-fura-2,运用PTi阳离子测定系统动态测HUVECs的[Mg2+]i。结果:Ang-1诱导的[Mg2+]i增加与细胞外Mg2+浓度无关。Ang-1诱导的[Mg2+]i增加与细胞内Ca2+浓度无关。经酪氨酸激酶阻断剂(tyrphostin A23和genistein),磷脂酰3激酶阻断剂(wortmannin和LY294002)预处理,均显著阻断Ang-1诱导的[Mg2+]i增加。但经活化丝裂原激活激酶阻断剂(SB202190和PD98059)预处理,不能阻断Ang-1诱导的[Mg2+]i增加。结论:Ang-1通过酪氨酸激酶/磷脂酰3激酶信号传递途径使细胞内的Mg2+库释放Mg2+,从而增加HUVECs的[Mg2+]i。

Modulatory Effect of Rg_1 on the Activity of ProteinTyrosine Kinase of Lymphocytes in the Elderly

The effect of Rg1,a saponin extracted froin Panax ginseng, on the phenotype,receptor and the activity of protein tyrosine kinase (PTK) of lymphocytes isolated from 7 healthy oldpersons were studied. The CD25, CD45RA and CD45RO phenotypes of lymphocytes were 4eter-mined by indirect immunofluorescence technique. The percentage of CD25, CD45RA and CD45ROpositive lymphocytes was 38.3%±17.3%, 46.0% 15.1%, and 52.6%±14.1% respectively after incu-bation with PHA (5 μ±/ml) for 72 hours. However, there were 58.0%±12.5%, CD25, 64.1% ± 12.4%,CD45RA, and 74.0%±8.0%, CD45RO positive cells in the presence of Rg, ( 1μg/ml) along with PHA(5 μg/ml) over the sanie period of incubation. A significant increase was induced by Rgi (P<0.05).The activities of PTK in the cytoplasm and membrane of lymphocytes were measured by ELISAmcthod after incubation with PHA or PHA+Rg1. The absorbance value of PTK activity in cytoplasmafter 72 hr incubation was 0. 120±0.020 in PHA group, but 0. 1 38±0.015 in PHA+Rg1 group. In thelymphocyte membrane, it was 0.374± 0.060 in PHA group and 0.403 ± 0.008 in PHA+Rg1 group(P<0.001). These results showed that Rgi significantly arid simultaneously increased both the PT Kactivity and the expression of phenotype of lymphocytes.

MiRNA-145-5p inhibits gastric cancer progression via the serpin family E member 1-extracellular signal-regulated kinase-1/2 axis

BACKGROUND MicroRNAs(miRNAs)regulate gene expression and play a critical role in cancer physiology.However,there is still a limited understanding of the function and regulatory mechanism of miRNAs in gastric cancer(GC).AIM To investigate the role and molecular mechanism of miRNA-145-5p(miR145-5p)in the progression of GC.METHODS Real-time polymerase chain reaction(RT-PCR)was used to detect miRNA expression in human GC tissues and cells.The ability of cancer cells to migrate and invade was assessed using wound-healing and transwell assays,respectively.Cell proliferation was measured using cell counting kit-8 and colony formation assays,and apoptosis was evaluated using flow cytometry.Expression of the epithelial-mesenchymal transition(EMT)-associated protein was determined by Western blot.Targets of miR-145-5p were predicated using bioinformatics analysis and verified using a dual-luciferase reporter system.Serpin family E member 1(SERPINE1)expression in GC tissues and cells was evaluated using RT-PCR and immunohistochemical staining.The correlation between SERPINE1 expression and overall patient survival was determined using Kaplan-Meier plot analysis.The association between SERPINE1 and GC progression was also tested.A rescue experiment of SERPINE1 overexpression was conducted to verify the relationship between this protein and miR-145-5p.The mechanism by which miR-145-5p influences GC progression was further explored by assessing tumor formation in nude mice.RESULTS GC tissues and cells had reduced miR-145-5p expression and SERPINE1 was identified as a direct target of this miRNA.Overexpression of miR-145-5p was associated with decreased GC cell proliferation,invasion,migration,and EMT,and these effects were reversed by forcing SERPINE1 expression.Kaplan-Meier plot analysis revealed that patients with higher SERPINE1 expression had a shorter survival rate than those with lower SERPINE1 expression.Nude mouse tumorigenesis experiments confirmed that miR-145-5p targets SERPINE1 to regulate extracellular signal-regulated kinase-1/2(ERK1/2).CONCLUSION This study found that miR-145-5p inhibits tumor progression and is expressed in lower amounts in patients with GC.MiR-145-5p was found to affect GC cell proliferation,migration,and invasion by negatively regulating SERPINE1 levels and controlling the ERK1/2 pathway.

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.

Research Progress on Targets and Selective Inhibitors of Polo-like Kinase-1(PLK-1)

In this paper,the biological function of PLK-1,the correlation between PLK-1 and tumors,and the latest research progress on PLK-1 inhibitors under study are reviewed,in order to provide references for the research and development of PLK-1 inhibitors.

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 &#x003b1;-smooth muscle actin (&#x003b1;-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. &#x003b1;-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, &#x003b1;-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.

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.

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.

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.

Treatment time influences the effects of a low-frequency pulsed electric field on synthesis of tyrosine hydroxylase and dopamine in PC12 cells

BACKGROUND： Electromagnetic radiation can influence dopamine （DA） synthesis in brain tissues or ceils, but electromagnetic frequencies, intensities, and radiation time can produce different effects. In addition, the signal pathway by which electromagnetic radiation influences DA synthesis remains controversial. OBJECTIVE： To determine tyrosine hydroxylase （TH） expression in PC12 cells and DA levels in cell culture media after different periods of low-frequency pulsed electric field （LF-PEF） stimulation, and to determine how LF-PEF signaling stimulates TH synthesis using inhibitors. DESIGN, TIME AND SETTING： A parallel, controlled, cell experiment was performed at the Laboratory of Cell Biology, School of Life Science, East China Normal University, between January and October 2006. MATERIALS： PC12 cells were purchased from the Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, China. Nerve growth factor was purchased from PeproTech, USA. The protein kinase A inhibitor, H-89, and mitogen-activated protein kinase kinase inhibitor, U0126, were purchased from Sigma, USA. METHODS： （1） Following routine culture in Dulbecco＇s modified eagle medium, primary PC12 cells were stimulated under LF-PEF （pulse frequency 50.Hz, pulse width 20 μs, peak field strength 1 V/m） for 5, 10, 15, 20, and 30 minutes. （2） Inhibitors （H-89 or U0126, 1 μmol/L） were added 30 minutes before LF-PEF stimulation for 10 minutes. MAIN OUTCOME MEASURES： （1） TH expression was determined by Western blot in PC12 cells at 0.5, 1,2, 3, and 4 days after LF-PEF stimulation. Similarly, DA was measured by high-performance liquid chromatography in media at 2, 3, 4, or 5 days after LF-PEE （2） TH expression was detected 1 day after H-89 or U0126 treatment and LF-PEE RESULTS： （1） Short-term LF-PEF stimulation （5 and 10 minutes） increased TH expression and media DA levels after short-term culture （2 days） （P 〈 0.01）, but both parameters decreased with longer culture （3 4 days） （P 〈 0.01）. Long-term LF-PEF stimulation （15, 20, or 30 minutes） decreased TH and DA synthesis, followed by a rapid increase （P 〈 0.01）. （2） H89 could completely inhibit TH expression in PC12 cells stimulated by LF-PEF for 10 minutes, while the inhibition rate of U0126 was 53.2%. CONCLUSION： Short-term LF-PEF first promotes then inhibits, while long-term LF-PEF first inhibits then promotes, TH and DA synthesis. LF-PEF stimulation regulates TH expression primarily by activating protein kinase A to regulate DA synthesis.

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.

Placenta Growth Factor and Soluble Fms-Like Tyrosine Kinase 1 in Preeclampsia and Normotensive Pregnant Nigerian Women

Background: Preeclampsia (PE) is still one of the leading causes of maternal/perinatal morbidity/mortality in Nigeria. Imbalance between placenta growth factor (PLGF) and soluble fms-like tyrosine kinase 1 (sFlt1) has been reportedly present both before and after the manifestation of PE;however, Nigerian data regarding these angiogenesis-related substances are lacking. We here attempted to determine the maternal serum level of PLGF and sFlt1 and sFlt1/PLGF ratio in PE vs. non-PE women in Lagos State University Teaching Hospital, Nigeria. Methods: An observational cross-sectional study was made on 75 women with PE and 75 age-gestational-age matched women without PE, as case and control, respectively. Levels of sFlt-1, PIGF and the sFlt-1: PIGF ratio was compared between the two. Results: Serum levels of Flt-1 and sFlt1/PIGF ratio were significantly higher in PE patients (6581.86 ± 865.75, and 146.42 ± 92.43) than in the normotensive control (4584.52 ± 1479.6 and 11.60 ± 6.42). PIGF was significantly lower in PE patients (70.14 ± 51.03) than the normotensives (494.06 ± 475.8). There were positive and negative correlations between the sFlt-1 and PLGF respectively and mean arterial blood pressure. Conclusion: Serum sFlt-1, sFlt1/PIGF ratio was significantly higher and PIGF levels were significantly lower in PE than normotensive control in Nigerian population.

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.

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.

RNAi沉默Polo-like kinase-1基因表达对大肠癌细胞端粒酶活性的影响

目的探讨polo-like kinase-1(PLK1)基因对大肠癌细胞增殖和端粒酶活性的影响。方法根据PLK1基因序列特点,设计并用化学方法合成小干扰核糖核酸分子(small interfering RNA,si RNA),转染人大肠癌SW480细胞后,分别采用实时定量PCR和Western blot检测PLK1基因mRNA和蛋白表达水平。分别采用MTT法和TRAP-ELISA方法检测PLK1基因转染对大肠癌细胞增殖和端粒酶活性的影响。结果所设计的5个si RNA均能明显抑制大肠癌SW480细胞PLK1 mRNA水平,以P4效果最好。以P4转染处理大肠癌细胞后,PLK1 mRNA水平和蛋白水平明显下调,且呈浓度和时间依赖性。MTT和TRAP-ELISA方法检测发现,P4si RNA转染组细胞增殖和端粒酶活性明显受到抑制,且呈浓度和时间依赖性(P<0.05,P<0.05)。结论PLK1基因对大肠癌细胞增殖具有重要的调控作用;以PLK1 si RNA转染处理大肠癌细胞,可明显抑制大肠癌细胞的恶性增殖,其机制可能与抑制端粒酶活性有关。

慢性肾小球肾炎患者MCP-1和sFlt-1表达与肾功能及预后的相关性研究

目的:分析慢性肾小球肾炎患者血清单核细胞趋化蛋白-1(MCP-1)和可溶性血管内皮细胞生长因子受体1(sFlt-1)水平变化及其与肾功能和预后的关系。方法:纳入2018-01—2020-03本院收治的慢性肾小球肾炎患者122例(研究组),选取同时期本院体检健康者128例(对照组)。研究组依据肾功能损害情况分为A组(肾功能正常16例)、B组(轻中度肾功能损害88例)、C组(重度肾功能损害18例);根据随访结局,将患者分为肾功能衰竭组(22例)和病情缓解组(100例)。采用酶联免疫吸附法(ELISA)检测受试者MCP-1、sFlt-1水平。采用全自动生化分析仪检测所有受试者血尿素氮(BUN)、血肌酐(Scr)水平,采用慢性肾脏疾病流行病学合作研究公式(CKD-EPI)估算肾小球滤过率(eGFR)。Pearson法分析MCP-1、sFlt-1与BUN、Scr、eGFR的相关性。采用受试者工作特征(ROC)曲线评价血清MCP-1、sFlt-1水平预测慢性肾小球肾炎患者预后的价值。结果:与对照组相比,研究组MCP-1、sFlt-1、BUN、Scr水平较高(P<0.05),eGFR较低(P<0.05)。C组BUN、Scr、MCP-1、sFlt-1水平明显高于A组、B组(P<0.05),B组BUN、Scr、MCP-1、sFlt-1水平明显高于A组(P<0.05)。Pearson相关性分析显示,MCP-1与BUN、Scr均呈正相关(P<0.05),与eGFR呈负相关(P<0.05),sFlt-1与BUN、Scr均呈正相关(P<0.05),与eGFR呈负相关(P<0.05)。与病情缓解组相比,肾功能衰竭组患者清中MCP-1、sFlt-1水平较高(P<0.05)。ROC分析显示,血清MCP-1、sFlt-1水平预测慢性肾小球肾炎患者预后的AUC分别为0.967、0.965,MCP-1联合sFlt-1预测慢性肾小球肾炎患者预后的AUC为0.984,灵敏度100.00%,特异度94.00%。结论:慢性肾小球肾炎患者血清MCP-1、sFlt-1水平明显上升,可作为患者预后评估的潜在生物学指标。

胎盘生长因子、可溶性fms样酪氨酸激酶-1及糖基化纤连蛋白在子痫前期预测中的应用价值

目的:探讨胎盘生长因子(placental growth factor,PLGF)、可溶性fms样酪氨酸激酶-1(soluble fms-like tyrosine kinase-1,SFLT-1)和糖基化纤连蛋白(glycosylated fibronectin,GLYFN)检测对子痫前期的预测价值。方法:选择在无锡市妇幼保健院就诊的188例孕妇,分154例正常孕妇(对照组)和34例子痫前期患者(子痫组),应用免疫荧光法分别检测其在孕16~18周血清中PLGF、SFLT-1和GLYFN的浓度,比较子痫前期组和对照组各标志物的水平,并使用受试者操作特征曲线(receiver operating characteristic,ROC)对3种标志物的预测价值进行效能评估。结果:在妊娠中期,子痫前期组血清PLGF浓度低于对照组,SFLT-1及GLYFN浓度均高于对照组,3种标志物的差异均有统计学意义(3指标P=0.000)。95%置信区间的ROC曲线下面积(areas under the ROC curve,AUC)为,PLGF为0.941(0.907~0.974),SFLT-1为0.881(0.800~0.962),GLYFN为0.951(0.918~0.985),联合指标SFLT-1和GLYFN、3项指标联合检测在ROC曲线下面积(areas under the ROC curve,AUC)分别为0.968、0.986。结论:PLGF、SFLT-1、GLYFN 3种标志物水平在对照组和子痫前期组均存在明显差异,对子痫前期的发病具有一定的预测价值,SFLT-1联合PLGF、SFLT-1联合GLYFN、3项指标联合检测对子痫前期的预测价值高于任一单项指标。