Timosaponin AⅢ induces drug-metabolizing enzymes by activating constitutive androstane receptor (CAR) via dephosphorylation of the EGFR signaling pathway

The current study aimed to assess the effect of timosaponin AⅢ(T-AⅢ)on drug-metabolizing enzymes during anticancer therapy.The in vivo experiments were conducted on nude and ICR mice.Following a 24-day administration of T-AⅢ,the nude mice exhibited an induction of CYP2B10,MDR1,and CYP3A11 expression in the liver tissues.In the ICR mice,the expression levels of CYP2B10 and MDR1 increased after a three-day T-AⅢ administration.The in vitro assessments with HepG2 cells revealed that T-AⅢ induced the expression of CYP2B6,MDR1,and CYP3A4,along with constitutive androstane receptor(CAR)activation.Treatment with CAR siRNA reversed the T-AⅢ-induced increases in CYP2B6 and CYP3A4 expression.Furthermore,other CAR target genes also showed a significant increase in the expression.The up-regulation of murine CAR was observed in the liver tissues of both nude and ICR mice.Subsequent findings demonstrated that T-AⅢ activated CAR by inhibiting ERK1/2 phosphorylation,with this effect being partially reversed by the ERK activator t-BHQ.Inhibition of the ERK1/2 signaling pathway was also observed in vivo.Additionally,T-AⅢ inhibited the phosphorylation of EGFR at Tyr1173 and Tyr845,and suppressed EGF-induced phosphorylation of EGFR,ERK,and CAR.In the nude mice,T-AⅢ also inhibited EGFR phosphorylation.These results collectively indicate that T-AⅢ is a novel CAR activator through inhibition of the EGFR pathway.

MEK/ERK signaling pathway in apoptosis of SW620 cell line and inhibition effect of resveratrol

Objective:To study the involvement of MAPK MEK/ERK signaling transduction pathway in the apoptosis process of SW620 tumor cell line and the inhibition effect of resveratrol.Methods:SW620 cell lines were divided into 5 groups,namely,control group.PD98059 group,low-dose resveratrol group,mid-dose resveratrol group and high-dose resveratrol group.The inhibition rate of cell proliferation was detected by MTT method.The expression of apoptotic molecules and MEK/ERK signaling pathway related proteins were assayed by realtime PCR and Western blotting.Results:Compared with control group,the proliferation of cells treated with resveratrol was significantly inhibited.In the case of apoptotic molecules,the expression of Bax,Caspase 3 and Caspase 9 was increased significantly while the expression of anti-apoptotic molecule Bcl2 was decreased significantly in resveratrol groups with a dosedependent manner.In the case of molecules in MEK/ERK signaling pathway,the expression of Ras,Raf,MEK and ERKl/2 was decreased significantly in resveratrol groups with a dose-dependent manner.Conclusions:PD98059 and resveratrol can effectively inhibit the proliferation of SW620 through inhibiting the MEK/ERK signaling pathway.

Endogenous hydrogen sulfide and ERK1/2-STAT3 signaling pathway may participate in the association between homocysteine and hypertension

Background Homocysteine(Hcy)is a risk factor for hypertension,although the mechanisms are poorly understood.Methods We first explored the relationship between Hcy levels and blood pressure(BP)by analyzing the clinical data of primary hypertensive patients admitted to our hospital.Secondly,we explored a rat model to study the effect of Hcy on blood pressure and the role of H2S.An hyperhomocysteinemia(HHcy)rat model was induced to explore the effect of Hcy on blood pressure and the possible mechanism.We carried out tissue histology,extraction and examination of RNA and protein.Finally,we conducted cell experiments to determine a likely mechanism through renin-angiotensin-aldosterone system(RAAS)and extracellular signal-regulated kinase 1/2(ERK1/2)signaling pathway.Results In primary hypertensive inpatients with HHcy,blood pressure was significantly higher as compared with inpatient counterparts lacking HHcy.In the rat model,blood pressure of the Wistar rats was significantly increased with increases in serum Hcy levels and decreased after folate treatment.Angiotensin converting enzyme 1(ACE1)expression in the Wistar Hcy group was enhanced comparing to controls,but was decreased in the Wistar folate group.Angiotensin II receptor type 1(AGTR1)levels in the kidney tissue increased in the Wistar folate group.Both serum H2S and kidney cystathionineγ-lyase decreased with elevated levels of serum Hcy.In vitro,increased concentrations and treatment times for Hcy were associated with increased expression of collagen type 1 and AGTR1.This dose and time dependent response was also observed for p-STAT3 and p-ERK1/2 expression.Conclusion Endogenous H2S might mediate the process of altered blood pressure in response to changes in serum Hcy levels,in a process that is partly dependent on activated RAAS and ERK1/2-STAT3 signaling pathway.

Acupuncture at Back-Shu point improves insomnia by reducing inflammation and inhibiting the ERK/NF-κB signaling pathway

BACKGROUND Insomnia is a disease where individuals cannot maintain a steady and stable sleep state or fail to fall asleep.Western medicine mainly uses sedatives and hypnotic drugs to treat insomnia,and long-term use is prone to drug resistance and other adverse reactions.Acupuncture has a good curative effect and unique advantages in the treatment of insomnia.AIM To explore the molecular mechanism of acupuncture at Back-Shu point for the treatment of insomnia.METHODS We first prepared a rat model of insomnia,and then carried out acupuncture for 7 consecutive days.After treatment,the sleep time and general behavior of the rats were determined.The Morris water maze test was used to assess the learning ability and spatial memory ability of the rats.The expression levels of inflammatory cytokines in serum and the hippocampus were detected by ELISA.qRTPCR was used to detect the mRNA expression changes in the ERK/NF-κB signaling pathway.Western blot and immunohistochemistry were carried out to evaluate the protein expression levels of RAF-1,MEK-2,ERK1/2 and NF-κB.RESULTS Acupuncture can prolong sleep duration,and improve mental state,activity,diet volume,learning ability and spatial memory.In addition,acupuncture increased the release of 1L-1β,1L-6 and TNF-αin serum and the hippocampus and inhibited the mRNA and protein expression of the ERK/NF-κB signaling pathway.CONCLUSION These findings suggest that acupuncture at Back-Shu point can inhibit the ERK/NF-κB signaling pathway and treat insomnia by increasing the release of inflammatory cytokines in the hippocampus.

The role of ERK1/2 signaling pathway in coronary microembolization-induced rat myocardial inflammation and injury

Objectives In this work,we explore the effect of atorvastatin on myocardial apoptosis and caspase-8 acti- vation after coronary microembolization(CME) in rats. Methods Fifty rats were randomly divided into five groups; the coronary microembolization(CME) group,the sham-operated (sham) control group,the gastric lavage control group, the atorvastatin lavage group,and the caspasse-8 inhibitor (N-acetyl-Ile-Glu-Thr-Asp-CHO,abbreviated as CHO) group,with 10 rats for each group.A microembolization ball was injected through the left ventricle for constructing the CME model.Animals in the sham control group were given an injection of physiological saline instead of the microembolization ball.Seven days before the operation,the atorvastatin group underwent gastric lavage with 20 mg/kg of atorvastatin once a day.Gastric lavage control animals underwent gastric lavage with an equivalent dose of physiological saline instead of the atorvastatin.Animals in the CHO group were given an intraperitoneal injection of 10 mg/kg of CHO 30 min before the operation.Six hours after the operation,cardiac ultrasonic detection was conducted on each group to measure the cardiac function indexes.TUNEL(Terminal-deoxynucleoitidyl transferase mediated dUTP nick end labeling) assays were used to measure myocardial apoptosis,and western blots were used to quantify the expression levels of activated caspase-3 and -8.Results(1) The echocardiographic parameters showed that,compared to the sham control animals,the left ventricular ejection fraction(LVEF) of the CME group was significantly decreased(P【0.05).In addition, cardiac sonography revealed a decrease in the left ventricular shortening fraction(FS) and cardiac output(CO), but an increase in the left ventricular end-diastolic dimension (LVEDd).Compared to the CME group,the atorvastatin and CHO groups exhibited significantly improved cardiac function (P【0.05).(2) When compared with the sham control,the myocardical apoptotic rate of the CME group,as well as the levels of activated caspase-3 and-8,increased significantly (P【0.05).The myocardial apoptotic rate,as well as the levels of activated caspase-3 and caspase-8 in the atorvastatin and CHO groups,decreased significandy(P【0.05) in comparison to the CME group.Conclusions The atorvastatin pretreatment clearly suppressed post-CME myocardial apoptosis and improved cardiac function.The most likely mechanism for these effects is the blockade of the myocardial death receptor -mediated apoptosis pathway.

Irisin Attenuates Osteoarthritis by Inhibiting Apoptosis of Osteocytes Through Activating Erk Signaling Pathway

Osteoarthritis(OA)is an inflammatory disease involving the joints that is prevalent in the global aging population.The purpose of this study is to determine whether irisin can attenuate osteoarthritis(OA)progression in anterior cruciate ligament transection(ACLT)mice models and the mechanism of irisin therapy effect on OA by increase the resistance of apoptosis in MLO-Y4 cells induced by mechanical stretch in vitro.Methods For in vivo study,3-month-old male C57BL/6 J mice were randomized to three groups,sham-operated,anterior cruciate ligament transection(ACLT)-operated treated with vehicle,and ACLT-operated treated with irisin by intraperitoneal injection once a week.Cartilage erosion was observed by HE staining.Osteoarthritis Research Society International(OARSI)scores were evaluated according to the safranin O stai-ning.The microstructure of tibia cortical bone,trabecular bone,and subchondral bone was analyzed by micro-CT and the bone histomorphometry has been administrated including mineral apposition rate(MAR).Edu staining and cck-8 were used for the detection of the proliferation of MLO-Y4 cells.For mechanical stress,cells were seeded on the collagen-I coated chamber subjected with a peak biaxial stretch of 20%at 1 Hz for 16 hours to induce apoptosis.Flow cytometry was used for the detection of apoptosis and cell cycle.TUNNEL was used for staining the apoptotic cells and rt-PCR was applied for quantifying the expression of mRNA such as Bax,Bcl-2,SOST,c-myc,Opg.Western blot was utilized to confirm the mechanism of how irisin decrease the osteocyte apoptosis.Results In vivo,irisin can attenuate articular cartilage degeneration.Irisin maintains the proportion of hyaline cartilage and calcified cartilage and keep fewer cartilage erosions in ACLT-operated mice.For immunohistochemical(IHC)staining,irisin reduced the expression of caspase3,Bax and matrix metalloproteinase-13 in both cartilage and subchondral bone.Irisin-treated ACLT group shows higher Trabecular number(Tb.N)and bone volume fraction(BV/TV)compared to the vehicle-treated ACLT group.In vitro, irisin significantly increased the proliferation of MLO-Y4 cells detected by Edu and Ki67 staining,and irisin can protect the cells from both mechanical stretchinduced apoptosis detected by FITC-PI flow cytometry and maintain the cell activity by regulating the expression of Bax,Bcl-2,and c-myc.Transcriptome sequencing shows that irisin significantly activates the MAPK signaling pathway and we confirm the result by western blot:irisin effectively activates the Erk signaling pathway through phosphorylation and has a certain activation effect on p38 signaling pathway,no activation was observed for FAK signaling pathway.Conclusions Irisin can attenuate the progression of OA by decrease the apoptosis of osteocyte,which can improve the microarchitecture of subchondral bone.Erk pathway activation plays an important role in reducing the apoptosis of osteocyte.

Maleylated-BSA induces TNF-α production through the ERK and NF-κB signaling pathways in murine RAW264.7 macrophages

Ligands for macrophage scavenger receptors are reported to induce a wide range of host cell responses, including the production of inflammatory cytokines;however, the underlying mechanisms have not yet been fully understood and which remain obscure. In this study, we have examined the effect of maleylated bovine serum albumin (maleylated-BSA), a well-known ligand of the scavenger receptor, on the murine macrophage cell line RAW264.7. Maleylated-BSA strongly induced the production of tumor necrosis factor-α (TNF-α) and induced phosphorylation of extracellular signal-regulated kinase (ERK) and NF-kB p65. We also observed that maleylated-BSA-induced TNF-α production was blocked by the ERK inhibitor U0126. Together, these data demonstrates that maleylated-BSA- induced production of TNF-α requires the ERK/NF-κB signaling cascade in murine RAW- 264.7 macrophages.

T3SS通过ERK/ROS信号通路促进铜绿假单胞菌侵袭肺上皮细胞的作用

目的探究Ⅲ型分泌型系统(type three secretion system,T3SS)在调控铜绿假单胞菌(Pseudomonas aeruginosa,PA)侵袭肺上皮细胞中的作用及具体机制。方法采用PA菌株感染人非小细胞肺癌A549细胞,分为未处理组、PAO1(PA实验室标准菌株)组、△exsA(缺失与T3SS转录激活相关的基因exsA)组、△pscJ(缺失与T3SS蛋白分泌相关基因pscJ)组和PAO1-E(经EGTA诱导后高表达T3SS基因)感染组。采用U0126抑制A549细胞ERK活性或通过apocynin(APO)/N-acetyl-L-cysteine(NAC)抑制A549细胞活性氧(reactive oxygen species,ROS)产生并随后感染PAO1或PAO1-E菌株,分为未处理组、PAO1或PAO1-E感染组、抑制剂处理组,以及抑制剂联合PAO1或PAO1-E感染组。选用庆大霉素杀伤胞外细菌并将细胞裂解液倍比稀释后涂布PA筛选平板,通过计数菌落形成单位(CFUs),明确PA感染后细胞内的细菌量;通过荧光探针标记以及流式细胞术检测感染后细胞内ROS水平;通过Western blot检测感染后ERK通路的活化情况。结果与PAO1感染组相比,△exsA和△pscJ感染组的细胞内细菌量减少(P<0.05,P<0.01),且伴随ROS产生减少(P<0.01),而PAO1-E感染组则呈现相反趋势(P<0.01)。PAO1或PAO1-E感染联合APO/NAC处理组的细胞内细菌量明显低于PAO1或PAO1-E感染组(P<0.01)。相较PAO1感染组,△exsA和△pscJ感染组的ERK磷酸化水平增加(P<0.01),而PAO1-E感染组的ERK磷酸化降低(P<0.01)。与PAO1感染组相比,PAO1联合U0126处理组的细胞ERK磷酸化水平降低,伴随ROS产生以及细胞内细菌量增加(P<0.01)。结论T3SS介导ERK通路抑制可通过促进肺上皮细胞ROS产生,增加PA对肺上皮细胞侵袭。

山茱萸提取物对慢性肾功能衰竭大鼠的肾保护作用及对oxidase/ROS/ERK信号通路的影响

目的:探讨山茱萸提取物对慢性肾功能衰竭(CRF)大鼠的肾保护作用及对氧化酶(oxidase)/活性氧(ROS)/细胞外信号调节激酶(ERK)信号通路的影响。方法:将40只雄性SD大鼠分为正常组、模型组、阳性药组和山茱萸组,每组10只。除正常组外,其余各组按0.25 g/(kg·d)的剂量灌胃腺嘌呤溶液,连续给予21 d制备CRF模型。模型制备成功后,阳性药组按0.75 g/(kg·d)的剂量给予黄葵胶囊,山茱萸组按0.60 g/(kg·d)的剂量给予山茱萸提取物,正常组和模型组给予等量生理盐水,持续28 d。对肾组织进行病理学检查及评分,同时检测肾功能指标、血清中肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)含量及肾脏中相关蛋白的含量。结果:正常组大鼠肾脏病理未观察到损伤迹象;模型组出现弥漫肾小球和肾小管萎缩、炎性细胞浸润和间质纤维化等病变;阳性药组肾小球和肾小管萎缩、炎性细胞浸润和间质纤维化等病变较模型组减轻;山茱萸组肾小球和肾小管萎缩、炎性细胞浸润和间质纤维化等病变程度介于模型组和阳性药组之间。与正常组比较,模型组炎症评分、纤维化评分及尿素氮(BUN)、肌酐(SCr)、尿蛋白(UP)、TNF-α、IL-6、α-平滑肌肌动蛋白(α-SMA)、NADPH氧化酶1(NOX1)、ROS、磷酸化ERK(p-ERK)含量均增加(P<0.05);与模型组比较,阳性药组和山茱萸组炎症评分、纤维化评分及BUN、SCr、UP、TNF-α、IL-6、α-SMA、NOX1、ROS、p-ERK含量均降低(P<0.05);与阳性药组比较,山茱萸组炎症评分、纤维化评分及BUN、SCr、UP、TNF-α、IL-6、α-SMA、NOX1、ROS、p-ERK含量均增加(P<0.05)。结论:山茱萸提取物可以通过抑制肾组织炎症反应和纤维化对CRF大鼠起到一定的保护作用,其机制可能与oxidase/ROS/ERK信号通路有关。

Estrogen up-regulates MMP2/9 expression in endometrial epithelial cell via VEGF-ERK1/2 pathway

Objective:To study the effect of estrogen on anovulatory dysfunctional uterine bleeding(ADUB).Methods:Primary endometrial epithelial cells of Hainan Lizu female was cultured and hydrolylic activity of gelalinase was determined by gelatin zymography analysis.Cellular mRNA and protein synthesis was blocked respectively to determine whether the increased expression of MMP-2/9 was induced by estrogen.The expression of VEGF was blocked by siRNA.After treatment with various factors.MMP-9,VEGF,total Erk and phosphorylated Erk expression in primary uterine epithelial cells was detected by Western blotting analysis.Cell MMP-2/9mRNA levels was measured by real-time RT-PCR.Results:The activity and expression of MMP2/9 was inereased in the endometrium of patients with ADUB.Estrogen could up-regulate the expression of VEGF and activate Erk 1/2-Elk1 signal path.After interference by siRNA,ERK1/2 pathway was blocked in cells,and the expression of MMP-2/9 was down-regulated.ERK1/2 specific blocker U0126 blocked ERK phosphorylation,and it could down-regulate the expression of MMP-2/9.Conclusions:The results showed that the estrogen can increase the expression of VEGF,and thus activate ERK1/2 pathway to induce MMP-2/9 expression.

Inhibitory effects of oxyresveratrol on ERK and Smad1/2 phosphorylation and HSC activation in preventing carbon tetrachloride-induced rat liver fibrosis

Oxyresveratrol(ORes,trans-2,4,3′,5′-tetrahydroxy stilbene)naturally exists in mulberry,grapes,peanuts and other plants.It belongs to stilbene polyphenolic family and has an extra hydroxyl group at 2-position comparing with resveratrol(Res).Hence,ORes has stronger antioxidant activity than resveratrol.In present study,we employed a rat hepatic fibrosis model induced by carbon tetrachloride(CCl_(4))and administrated ORes via gavage feeding to study the protective effects and potential mechanisms of ORes against hepatic fibrosis.We demonstrated that rat liver oxidative damage induced by CCl_(4)was significantly alleviated after ORes feeding.Furthermore,the mRNA transcription levels ofα-smooth muscle actinn(˛-SMA),desmin,and two MMPs(MMP2 and MMP9)were reduced and the expression levels of transforming growth factorβ1(TGF-β1),p-small mother against decapen-taplegic protein(Smad)1/2 and p-extracellular signal-regulated kinases(ERK)1/2 in the liver tissue down-regulated dramatically.In a parallel study with Res,ORes showed more efficacious protective effect than Res against rat liver fibrosis,which is attributed to extended conjugation system due to the extra hydroxyl group at 2-position on ORes making it more electron-rich and susceptible to oxidation than Res.Therefore,dietary consumption of mulberry and other fruits containing ORes may be beneficial in the prevention of liver fibrosis.

Tobacco-specific Carcinogen 4-(Methylnitrosoamino)-1-(3-pyridyl)-1-butanone(NNK) Activating ERK1/2 MAP Kinases and Stimulating Proliferation of Human Mammary Epithelial Cells

Cigarette smoking is correlated with the development of various cancers. 4- （Methylnitresoamino） -1- （3-pyridyl） - 1-butanone（NNK） is one of the major tobacco-specific carcinogens in the cigarette smoke, which increases the risk of breast cancer. In the present study, it was demonstrated that NNK rapidly activated ERK1 and ERK2 MAP kinases in human normal mammary epithelial cells. It was found that there are two different routes for the activation of ERK1/2 with NNK. One is from nicotinic receptor nAchR to MEK1/2, and the other is from tyrosine kinase containing receptor to MEK1/2. The tobacco-specific carcinogen NNK shows a strong proliferative effect on normal human mammary epithelial cells and cancer mammary epithelial cells.

Protective effects of Yishen Sanjie Huayu compound on the renal artery disease in rats with IgA nephropathy through ERK/NF-κB pathway

Objective:To observe the effect of Yishen Sanjie Huayu compound prescription on ERK/NF-κB signaling pathway in IgA nephropathy(IgAN)rats,and explore its effect on preventing and treating IgA nephropathy intrarenal arteriole disease.Methods:Fifty-five male SD rats were randomly divided into blank group,model group,ShenfukangⅡcapsule group and Losartan potassium tablet group.Bovine serum albumin(BSA)was used for intragastric administration and carbon tetrachloride(CCl4).IgAN rat model was established by subcutaneous injection and lipopolysaccharide(LPS)tail vein injection.ShenfukangⅡcapsule group and Losartan potassium tablet group were given each drug suspension 2ml/head/d one week after modeling Gavage was started.The blank group and the model group were given an equal volume of normal saline.The 24h urine protein(UTP)of the rats was measured at 4,8,and 12 weeks after the administration,and the blood creatinine(SCr)was measured after 12 weeks.,urea nitrogen(BUN),aldosterone(ADS),angiotensinⅡ(AngⅡ),immunohistochemical Envi-sion System two-step method to detect vascular endothelial growth factor(VEGF)and human matrix in the whole rat kidney and small artery area The expression of metalloproteinase-9(MMP-9),proliferating cell nuclear antigen(PCNA),extracellular regulatory protein kinase(ERK)1/2,nuclear transcription factor-κB(NF-κB),and the small arteries of rat kidney tissue The intima,media,vessel wall/vascular outer diameter value.Results:Compared with the model group,the expressions of VEGF,MMP-9,PCNA,ERK1/2 and NF-κB in kidney tissues of the ShenfukangⅡcapsule group and the Losartan potassium tablet group decreased(P<0.05),24hUTP and SCr,BUN level decreased(P<0.05),kidney tissue damage was alleviated;intima and vessel wall/vascular outer diameter values were significantly reduced(P<0.01),there was no significant difference in ADS between the groups.The AngⅡof the Tanpotassium tablets group was lower than that of the model group(P<0.05).Conclusion:Yishen Sanjie Huayu compound can inhibit the ERK/NF-κB signaling pathway in rats with IgA nephropathy,reduce the levels of VEGF,MMP-9,PCNA,ERK1/2,NF-κB,and inhibit intrarenal arteriole vascular endothelial cells Proliferate and reduce kidney damage.

Anti-diabetic potential of apigenin,luteolin,and baicalein via partially activating PI3K/Akt/GLUT-4 signaling pathways in insulin-resistant HepG2 cells

Dietary flavonoids are abundant in natural plants and possess multiple pharmacological and nutritional activities.In this study,apigenin,luteolin,and baicalein were chosen to evaluate their anti-diabetic effect in high-glucose and dexamethasone induced insulin-resistant(IR)HepG2 cells.All flavonoids improves the glucose consumption and glycogen synthesis abilities in IR-HepG2 cells via activating glucose transporter protein 4(GLUT4)and phosphor-glycogen synthase kinase(GSK-3β).These fl avonoids signifi cantly inhibited the production of reactive oxygen species(ROS)and advanced glycation end-products(AGEs),which were closely related to the suppression of the phosphorylation form of NF-κB and P65.The expression levels of insulin receptor substrate-1(IRS-1),insulin receptor substrate-2(IRS-2)and phosphatidylinositol 3-kinase(PI3K)/protein kinase B(Akt)pathway in IR-HepG2 cells were all partially activated by the fl avonoids,with variable effects.Furthermore,the intracellular metabolic conditions of the fl avonoids were also evaluated.

Effect of Guizhi Fuling Pill combined with GnRH analog on cell proliferation and invasion as well as MEK/ERK pathway in endometriosis lesions

Objective: To study the effect of Guizhi Fuling Pill combined with gonadotropin-releasing hormone analog (GnRH-a) on cell proliferation and invasion as well as MEK/ERK pathway in endometriosis lesions. Methods: Patients who were diagnosed with endometriosis in Bazhong Hospital of Traditional Chinese Medicine between November 2014 and March 2017 were selected as the research subjects and randomly divided into two groups, observation group received preoperative Guizhi Fuling Pill combined with GnRH analog therapy, and control group received preoperative GnRH analog monotherapy. After surgical resection, the endometriosis lesion was collected to determine the mRNA expression of proliferation and invasion-related genes as well as the protein expression of MEK/ERK pathway molecules. Results: Id-1, Sema3A, c-IAP1, OPN and uPA mRNA expression as well as p-MEK, p-EKR1/2, caspase-3 and MMP2 protein expression in endometriosis lesion of observation group were significantly lower than those of control group while Bak, Smac, PAI-1, TIMP1 and TIMP2 mRNA expression as well as caspase-3 protein expression were significantly higher than those of control group. Conclusion: Guizhi Fuling Pill combined with GnRH analog can inhibit the cell proliferation and invasion as well as the MEK/ERK pathway activation in endometriosis lesions.

Hepatitis B virus X protein promotes liver cell proliferation via a positive cascade loop involving arachidonic acid metabolism and p-ERK1/2

Hepatitis B virus X protein （HBx） plays a crucial role in the development of hepatocellular carcinoma. Here, we sought to identify the mechanisms by which HBx mediates liver cell proliferation. We found that HBx upregulated the levels of cyclooxygenase-2 （COX-2）, 5-1ipoxygenase （5-LOX） and phosphorylated extracellular signal-regulated protein kinases 1/2 （p-ERK1/2） in liver cells. HBx-induced p-ERK1/2 was abolished by inhibition of Gi/o proteins, COX or LOX. In addition, HBx increased the amounts of prostaglandin E2 （PGE2） and leukotriene B4 （LTB4） released from cell lines derived from hepatocytes. Moreover, these released arachidonic acid metabolites were able to activate ERK1/2. Interestingly, activated ERK1/2 could upregulate the expression of COX-2 and 5-LOX in a positive feedback manner. In conclusion, HBx enhances and maintains liver cell proliferation via a positive feedback loop involving COX-2, 5-LOX, released arachidonic acid metabolites, Gi/o proteins and p-ERK1/2.

Hypoxia-inducible factor-1α–mediated upregulation of CD99 promotes the proliferation of placental mesenchymal stem cells by regulating ERK1/2

BACKGROUND As human placenta-derived mesenchymal stem cells(hP-MSCs)exist in a physiologically hypoxic microenvironment,various studies have focused on the influence of hypoxia.However,the underlying mechanisms remain to be further explored.AIM The aim was to reveal the possible mechanisms by which hypoxia enhances the proliferation of hP-MSCs.METHODS A hypoxic cell incubator(2.5%O2)was used to mimic a hypoxic microenvironment.Cell counting kit-8 and 5-ethynyl-20-deoxyuridine incorporation assays were used to assay the proliferation of hP-MSCs.The cell cycle was profiled by flow cytometry.Transcriptome profiling of hP-MSCs under hypoxia was performed by RNA sequencing.CD99 mRNA expression was assayed by reverse transcription-polymerase chain reaction.Small interfering RNA-mediated hypoxia-inducible factor 1α(HIF-1α)or CD99 knockdown of hP-MSCs,luciferase reporter assays,and the ERK1/2 signaling inhibitor PD98059 were used in the mechanistic analysis.Protein expression was assayed by western blotting;immunofluorescence assays were conducted to evaluate changes in expression levels.RESULTS Hypoxia enhanced hP-MSC proliferation,increased the expression of cyclin E1,cyclin-dependent kinase 2,and cyclin A2,and decreased the expression of p21.Under hypoxia,CD99 expression was increased by HIF-1α.CD99-specific small interfering RNA or the ERK1/2 signaling inhibitor PD98059 abrogated the hypoxia-induced increase in cell proliferation.CONCLUSION Hypoxia promoted hP-MSCs proliferation in a manner dependent on CD99 regulation of the MAPK/ERK signaling pathway in vitro.

Cytokine receptor-like factor 1(CRLF1)promotes cardiac fibrosis via ERK1/2 signaling pathway

Cardiac fibrosis is a cause of morbidity and mortality in people with heart disease.Anti-fibrosis treatment is a significant therapy for heart disease,but there is still no thorough understanding of fibrotic mechanisms.This study was carried out to ascertain the functions of cytokine receptor-like factor 1(CRLF1)in cardiac fibrosis and clarify its regulatory mechanisms.We found that CRLF1 was expressed predominantly in cardiac fibroblasts.Its expression was up-regulated not only in a mouse heart fibrotic model induced by myocardial infarction,but also in mouse and human cardiac fibroblasts provoked by transforming growth factor-β1(TGF-β1).Gain-and loss-of-function experiments of CRLF1 were carried out in neonatal mice cardiac fibroblasts(NMCFs)with or without TGF-β1 stimulation.CRLF1 overexpression increased cell viability,collagen production,cell proliferation capacity,and myofibroblast transformation of NMCFs with or without TGF-β1 stimulation,while silencing of CRLF1 had the opposite effects.An inhibitor of the extracellular signal-regulated kinase 1/2(ERK1/2)signaling pathway and different inhibitors of TGF-β1 signaling cascades,comprising mothers against decapentaplegic homolog(SMAD)-dependent and SMAD-independent pathways,were applied to investigate the mechanisms involved.CRLF1 exerted its functions by activating the ERK1/2 signaling pathway.Furthermore,the SMAD-dependent pathway,not the SMAD-independent pathway,was responsible for CRLF1 up-regulation in NMCFs treated with TGF-β1.In summary,activation of the TGF-β1/SMAD signaling pathway in cardiac fibrosis increased CRLF1 expression.CRLF1 then aggravated cardiac fibrosis by activating the ERK1/2 signaling pathway.CRLF1 could become a novel potential target for intervention and remedy of cardiac fibrosis.

Circ_0053943 complexed with IGF2BP3 drives uveal melanoma progression via regulating N6-methyladenosine modification of Epidermal growth factor receptor

Numerous studies have characterized the critical role of circular RNAs(circRNAs)as regulatory factors in the progression of multiple cancers.However,the biological functions of circRNAs and their underlying molecular mechanisms in the progression of uveal melanoma(UM)remain enigmatic.In this study,we identified a novel circRNA,circ_0053943,through re-analysis of UM microarray data and quantitative RT-PCR.Circ_0053943 was found to be upregulated in UM and to promote the proliferation and metastatic ability of UM cells in both in vitro and in vivo settings.Mechanistically,circ_0053943 was observed to bind to the KH1 and KH2 domains of insulin-like growth factor 2 mRNA-binding protein 3(IGF2BP3),thereby enhancing the function of IGF2BP3 by stabilizing its target mRNA.RNA sequencing assays identified epidermal growth factor receptor(EGFR)as a target gene of circ_0053943 and IGF2BP3 at the transcriptional level.Rescue assays demonstrated that circ_0053943 exerts its biological function by stabilizing EGFR mRNA and regulating the downstream mitogen-activated protein kinase/extracellular signal-regulated kinase(MAPK/ERK)signaling pathway.Collectively,circ_0053943 may promote UM progression by stabilizing EGFR mRNA and activating the MAPK/ERK signaling pathway through the formation of a circ_0053943/IGF2BP3/EGFR RNA-protein ternary complex,thus providing a potential biomarker and therapeutic target for UM.

脱氧核苷酸转移酶末端相互作用蛋白1通过ERK信号通路促进鼻咽癌细胞侵袭及转移机制研究

目的探讨脱氧核苷酸转移酶末端相互作用蛋白1(deoxynucleotidyltransferase,terminal,interacting protein 1,DNTTIP1)通过细胞外调节蛋白激酶(extracellular regulated protein kinases,ERK)信号通路促进鼻咽癌侵袭及转移机制。方法选用人鼻咽癌细胞系(HK1)作为研究对象,分为观察组与对照组,观察组中细胞转入含有DNTTIP1基因的载体,对照组转入空白载体。采用Trizol法提取细胞中的总RNA,细胞划痕及Transwell小室实验检测细胞的迁移及侵袭能力,Western blot法检测ERK信号通路相关蛋白的表达情况。结果DNTTIP1在观察组HK1细胞中的表达水平明显高于对照组(2.75±0.43 vs.1.00±0.01),差异有统计学意义(t=9.966,P<0.05)。观察组中HK1细胞迁移及侵袭明显增强,差异有统计学意义(P<0.05)。与对照组比较,观察组HK1细胞中的p-ERKl/2蛋白表达水平明显上升(0.64±0.13 vs.1.26±0.15),差异有统计学意义(t=7.651,P<0.05)。ERK+3'-UTR+DNTTIP1组中ERK相对表达量明显高于ERK+3'-UTR组(1.71±0.21 vs.1.00±0.01),差异有统计学意义(t=8.272,P<0.05)。结论DNTTIP1通过ERK信号通路促进鼻咽癌侵袭及转移,该通路对鼻咽癌相关疾病的治疗具有潜在的医学价值。