Transcription factor glucocorticoid modulatory element-binding protein 1 promotes hepatocellular carcinoma progression by activating Yes-associate protein 1

BACKGROUND Glucocorticoid modulatory element-binding protein 1(GMEB1),which has been identified as a transcription factor,is a protein widely expressed in various tissues.Reportedly,the dysregulation of GMEB1 is linked to the genesis and development of multiple cancers.AIM To explore GMEB1’s biological functions in hepatocellular carcinoma(HCC)and figuring out the molecular mechanism.METHODS GMEB1 expression in HCC tissues was analyzed employing the StarBase database.Immunohistochemical staining,Western blotting and quantitative realtime PCR were conducted to examine GMEB1 and Yes-associate protein 1(YAP1)expression in HCC cells and tissues.Cell counting kit-8 assay,Transwell assay and flow cytometry were utilized to examine HCC cell proliferation,migration,invasion and apoptosis,respectively.The JASPAR database was employed for predicting the binding site of GMEB1 with YAP1 promoter.Dual-luciferase reporter gene assay and chromatin immunoprecipitation-qPCR were conducted to verify the binding relationship of GMEB1 with YAP1 promoter region.RESULTS GMEB1 was up-regulated in HCC cells and tissues,and GMEB1 expression was correlated to the tumor size and TNM stage of HCC patients.GMEB1 overexpression facilitated HCC cell multiplication,migration,and invasion,and suppressed the apoptosis,whereas GMEB1 knockdown had the opposite effects.GMEB1 bound to YAP1 promoter region and positively regulated YAP1 expression in HCC cells.CONCLUSION GMEB1 facilitates HCC malignant proliferation and metastasis by promoting the transcription of the YAP1 promoter region.

Reactive oxygen species-induced activation of Yes-associated protein-1 through the c-Myc pathway is a therapeutic target in hepatocellular carcinoma

BACKGROUND The Hippo signaling pathway regulates organ size by regulating cell proliferation and apoptosis with terminal effectors including Yes-associated protein-1(YAP-1).Dysregulation in Hippo pathway has been proposed as one of the therapeutic targets in hepatocarcinogenesis.The levels of reactive oxygen species(ROS)increase during the progression from early to advanced hepatocellular carcinoma(HCC).AIM To study the activation of YAP-1 by ROS-induced damage in HCC and the involved signaling pathway.METHODS The expression of YAP-1 in HCC cells(Huh-7,HepG2,and SNU-761)was quantified using real-time polymerase chain reaction and immunoblotting.Human HCC cells were treated with H2O2,which is a major component of ROS in living organisms,and with either YAP-1 small interfering RNA(siRNA)or control siRNA.To investigate the role of YAP-1 in HCC cells under oxidative stress,MTS assays were performed.Immunoblotting was performed to evaluate the signaling pathway responsible for the activation of YAP-1.Eighty-eight surgically resected frozen HCC tissue samples and 88 nontumor liver tissue samples were used for gene expression analyses.RESULTS H2O2 treatment increased the mRNA and protein expression of YAP-1 in HCC cells(Huh-7,HepG2,and SNU-761).Suppression of YAP-1 using siRNA transfection resulted in a significant decrease in tumor proliferation during H2O2 treatment both in vitro and in vivo(both P<0.05).The oncogenic action of YAP-1 occurred via the activation of the c-Myc pathway,leading to the upregulation of components of the unfolded protein response(UPR),including 78-kDa glucoseregulated protein and activating transcription factor-6(ATF-6).The YAP-1 mRNA levels in human HCC tissues were upregulated by 2.6-fold compared with those in nontumor tissues(P<0.05)and were positively correlated with the ATF-6 Levels(Pearson’s coefficient=0.299;P<0.05).CONCLUSION This study shows a novel connection between YAP-1 and the UPR through the c-Myc pathway during oxidative stress in HCC.The ROS-induced activation of YAP-1 via the c-Myc pathway,which leads to the activation of the UPR pathway,might be a therapeutic target in HCC.

重组人HMGB1调控内皮细胞成血管作用的机制初探

目的探讨重组人高迁移率族蛋白1(rhHMGB1)在调控内皮细胞成血管过程中可能涉及的机制。方法将内皮细胞分为对照组、骨髓间充质干细胞(MSC)上清组以及rhHMGB1组。采用细胞计数试剂(CCK)-8法检测内皮细胞的增殖、存活情况;采用蛋白质印迹法检测血管内皮生长因子(VEGF)、Yes相关蛋白(YAP)、CD31、缺氧诱导因子(HIF)-1α的蛋白相对表达量;采用实时荧光定量聚合酶链反应(RT-qPCR)检测VEGF、YAP、CD31、HIF-1α的信使RNA(mRNA)相对表达量;采用Transwell实验检测内皮细胞迁移水平;免疫荧光实验检测YAP定位情况。结果与对照组比较,rhHMGB1组内皮细胞迁移率增加(P<0.05),且细胞迁移率随着时间的延长而增加。与对照组比较,MSC上清组VEGF蛋白相对表达量增加,p-YAP蛋白表达增多,差异均有统计学意义(均为P<0.05)。与对照组比较,rhHMGB1组的VEGF和HIF-1α蛋白相对表达量以及VEGF和CD31 mRNA相对表达量均增加,YAP和p-YAP蛋白表达均增多,YAP/p-YAP比值增加,差异均有统计学意义(均为P<0.05)。与MSC上清组比较,rhHMGB1组的CD31 mRNA相对表达量增加,YAP蛋白表达增多,YAP/p-YAP比值增加,差异均有统计学意义(均为P<0.05)。结论外源高浓度rhHMGB1可能通过介导YAP入核促进内皮细胞的迁移能力,并上调血管生成相关蛋白的表达。

Yes-associated protein promotes endothelial-tomesenchymal transition of endothelial cells in choroidal neovascularization fibrosis

AIM:To reveal whether and how Yes-associated protein(YAP)promotes the occurrence of subretinal fibrosis in agerelated macular degeneration(AMD).METHODS:Cobalt chloride(Co Cl2)was used in primary human umbilical vein endothelial cells(HUVECs)to induce hypoxia in vitro.Eight-week-old male C57 BL/6 J mice weighing 19-25 g were used for a choroidal neovascularization(CNV)model induced by laser photocoagulation in vivo.Expression levels of YAP,phosphorylated YAP,mesenchymal markers[αsmooth muscle actin(α-SMA),vimentin,and Snail],and endothelial cell markers(CD31 and zonula occludens 1)were measured by Western blotting,quantitative real-time PCR,and immunofluorescence microscopy.Small molecules YC-1(Lificiguat,a specific inhibitor of hypoxia-inducible factor 1α),CA3(CIL56,an inhibitor of YAP),and XMU-MP-1(an inhibitor of Hippo kinase MST1/2,which activates YAP)were used to explore the underlying mechanism.RESULTS:Co Cl2 increased expression of mesenchymal markers,decreased expression of endothelial cell markers,and enhanced the ability of primary HUVECs to proliferate and migrate.YC-1 suppressed hypoxia-induced endothelialto-mesenchymal transition(End MT).Moreover,hypoxia promoted total expression,inhibited phosphorylation,and enhanced the transcriptional activity of YAP.XMU-MP-1 enhanced hypoxia-induced End MT,whereas CA3 elicited the opposite effect.Expression of YAP,α-SMA,and vimentin were upregulated in the laser-induced CNV model.However,silencing of YAP by vitreous injection of small interfering RNA targeting YAP could reverse these changes.CONCLUSION:The findings reveal a critical role of the hypoxia-inducible factor-1α(HIF-1α)/YAP signaling axis in End MT and provide a new therapeutic target for treatment of subretinal fibrosis in AMD.

LncRNA KCNQ1OT1在肝癌组织和肝癌细胞系中表达及对肝癌干细胞自我更新能力的调节作用观察

目的观察长链非编码RNA KCNQ1OT1在肝癌组织和肝癌细胞系中表达及对肝癌干细胞自我更新能力的调节作用,并探讨其机制。方法采用RT-PCR法检测肝癌组织与癌旁组织、肝癌细胞系(Huh7、SMMC7721、Hep3B)与人永生化正常肝上皮细胞LO2中KCNQ1OT1。使用肝癌细胞系Huh7筛选获得CD13+CD133+的肝癌干细胞,分为A、B、C组,B组转染小干扰RNA技术抑制KCNQ1OT1表达的KCNQ1OT1敲降质粒KCNQ1OT1 shRNA,C组转染KCNQ1OT1 shRNA后转染YAP1过表达载体。采用细胞成球实验观察各组肝癌干细胞成球能力,采用克隆形成实验观察各组肝癌干细胞克隆形成能力,采用CCK8实验观察各组肝癌干细胞增殖能力。采用RT-PCR法检测各组肝癌干细胞中Hippo-YAP通路靶基因Yap1、Birc5、Foxm1 mRNA。结果肝癌组织中KCNQ1OT1的相对表达量高于癌旁组织(P<0.05),Huh7、SMMC7721、Hep3B细胞中KCNQ1OT1的相对表达量高于L02细胞(P均<0.05)。B组肝癌干细胞成球率、克隆形成数、24、48、72、96 h时的OD值均低于A、C组(P均<0.05)。B组肝癌干细胞中Yap1、Birc5、Foxm1 mRNA相对表达量均低于A、C组(P均<0.05)。结论KCNQ1OT1在肝癌组织和肝癌细胞系中高表达;抑制KCNQ1OT1表达可以降低肝癌干细胞的自我更新能力,高表达YAP1可拮抗此过程;KCNQ1OT1可能是通过激活Hippo-YAP信号通路影响肝癌干细胞的自我更新能力。

Expression of Yes-associated protein 1 gene and protein in oral squamous cell carcinoma

Background Oral squamous cell carcinoma （OSCC） is one of the most common malignancies in the oral and maxillofacial region. Yes-associated protein 1 （YAP1） has been implicated as a bona fide oncogene in solid tumors. We seek to elucidate the role of YAP1 in OSCC tissue. Methods We identified YAP1 gene and protein overexpression in 30 OSCC patients and 10 normal oral mucosa tissues by immunohistochemistry, Western blotting and reverse transcription polymerase chain reaction （RT-PCR）. Results In the normal oral mucosa by immunohistochemical staining, YAP1 mainly located in both the cytoplasm and nucleus mainly the nuclei of the basal cells. In OSCC, the expression of YAP1 translocated from the nucleus to cytoplasm YAP1 being mainly located in both the cytoplasm and nucleus of the adjacent mucosa. The expression of YAP1 gradual increased in normal oral mucosa, tumor adjacent mucosa and low grade, middle grade, high grade OSCC tissue by Western blotting. Significant difference was found between the expressions of the normal oral mucosa and OSCC tissue （P 〈0.05）. The coincidence was detected between the normal oral mucosa and OSCC tissue by RT-PCR （P 〈0.05）. Conclusions YAP1 is involved in the carcinogenesis and development of OSCC. There is a transformation between nucleus and cytoplasm.

Yes-associated protein-1 may serve as a diagnostic marker and therapeutic target for residual/recurrent hepatocellular carcinoma post-transarterial chemoembolization

Background and aim:The transcriptional co-activator Yes-associated protein-1(YAP1)has been impli-cated as an oncogene and is overexpressed in different kinds of human cancers,especially hepatocellular carcinoma(HCC).However,the role of YAP1 has not been reported in residual/recurrent HCC after transarterial chemoembolization(TACE).Our aim is to determine whether YAP1 is overexpressed in the residual/recurrent HCC after TACE.Methods:A total of 105 tumor tissues from 71 patients including 30 cases of primary HCC without prior treatment,35 cases of residual/recurrent HCC post TACE,and 6 cases of hepatoblastoma were included in the immunohistochemical study.YAP1 immunoreactivity was blindly scored as 0,1+,2+or 3+in density and percentages of positive cells.Results:About 33.3%(10/30)of primary HCC without prior treatment showed 2+of YAP1 immunore-activity.While 82.8%(29/35)of residual/recurrent HCCs after TACE treatment displayed 2-3+of YAP1 immunoreactivity,which was significantly higher compared to primary HCC without prior treatment(P=0.0002).YAP1 immunoreactivity was moderately to strongly positive(2-3+)in 100%of the hep-atoblastoma,particularly in the embryonal components(3+in 100%cases).Conclusions:YAP1 is significantly upregulated in the residual/recurrent HCCs post TACE treatment,suggesting that YAP1 may serve as a sensitive diagnostic marker and a treatment target for residual/recurrent HCC post TACE.

GRK2 mediated degradation of SAV1 initiates hyperplasia of fibroblast-like synoviocytes in rheumatoid arthritis

Hyperplasia and migration of fibroblast-like synoviocytes(FLSs)are the key drivers in the pathogenesis of rheumatoid arthritis(RA)and joint destruction.Abundant Yes-associated protein(YAP),which is a powerful transcription co-activator for proliferative genes,was observed in the nucleus of inflammatory FLSs with unknown upstream mechanisms.Using Gene Expression Omnibus database analysis,it was found that Salvador homolog-1(SAV1),the pivotal negative regulator of the Hippo-YAP pathway,was slightly downregulated in RA synovium.However,SAV1 protein expression is extremely reduced.Subsequently,it was revealed that SAV1 is phosphorylated,ubiquitinated,and degraded by interacting with an important serine-threonine kinase,G protein-coupled receptor(GPCR)kinase 2(GRK2),which was predominately upregulated by GPCR activation induced by ligands such as prostaglandin E2(PGE2)in RA.This process further contributes to the decreased phosphorylation,nuclear translocation,and transcriptional potency of YAP,and leads to aberrant FLSs proliferation.Genetic depletion of GRK2 or inhibition of GRK2 by paroxetine rescued SAV1 expression and restored YAP phosphorylation and finally inhibited RA FLSs proliferation and migration.Similarly,paroxetine treatment effectively reduced the abnormal proliferation of FLSs in a rat model of collagen-induced arthritis which was accompanied by a significant improvement in clinical manifestations.Collectively,these results elucidate the significance of GRK2 regulation of Hippo-YAP signaling in FLSs proliferation and migration and the potential application of GRK2 inhibition in the treatment of FLSs-driven joint destruction in RA.

Increased Cthrcl Activates Normal Fibroblasts and Suppresses Keloid Fibroblasts by Inhibiting TGF-β/Smad Signal Pathway and Modulating YAP Subcellular Location

Keloid may induce severe impairment of life quality for the patients,although keloid is a cutaneous benign tumor.Collagen triple helix repeat containing protein 1 (Cthrc1) was identified as a novel gene that was originally found in adventitial fibroblasts after arterial injury.To address the role of Cthrcl in keloid,the expression level of Cthrcl was assessed in normal skin and keloid tissue,as well as in normal fibroblasts (NFs)and keloid fibroblasts (KFs)by using quantitative PCR,Western blotting and immunohistochemical analysis.The results showed that Cthrcl was increased in keloid tissue and KFs as compared with normal skin and NFs.Meanwhile,CCK8 and Transwell assays found the cellular proliferation and migration of KFs were increased as compared with NFs.Further,to verify the function of Cthrcl in NFs and K.Fs,we increased Cthrcl expression by transfecting lentivirns (LV) vectors LV-Cthrcl.The cellular proliferation and migration,collagen synthesis and the influence on TGF-β and YAP signaling were tested.The cellular proliferation and migration were increased in NFs-Cthrcl as compared with NFs-control.Meanwhile,YAP expression and nuclear-location was increased in NFs-Cthrcl.On the contrary,when Cthrcl was overexpressed in KFs,the cellular migration was suppressed and YAP expression was reduced and transferred to cytoplasm in KFs-Cthrcl as compared with KFs-control.But the expression level of collagen I was decreased and pSmad2/3 nucleus transfer was suppressed in both NFs-Cthrc1 and KFs-Cthrc1 by using Western blotting and immunofluorescence.Increased Cthrcl activated NFs by promoting YAP nucleus translocation,whereas suppressed KFs by inhibiting YAP nucleus translocation.Enhanced Cthrcl decreased collagen I in both NFs and KFs by inhibiting TGF-β/Smad pathway.In conclusion,Cthrcl may play a role in the pathogenesis of keloid by inhibiting collagen synthesis and fibroblasts migration via suppressing TGF-β/Smad pathway and YAP nucleus translocation.

Hippo-YAP/TAZ signaling in breast cancer:Reciprocal regulation of microRNAs and implications in precision medicine

Breast cancer is a molecularly heterogeneous disease and the most common female malignancy.In recent years,therapy approaches have evolved to accommodate molecular diversity,with a focus on more biologically based therapies to minimize negative consequences.To regulate cell fate in human breast cells,the Hippo signaling pathway has been associated with the alpha subtype of estrogen receptors.This pathway regulates tissue size,regeneration,and healing,as well as the survival of tissue-specific stem cells,proliferation,and apoptosis in a variety of organs,allowing for cell differentiation.Hippo signaling is mediated by the kinases MST1,MST2,LATS1,and LATS2,as well as the adaptor proteins SAV1 and MOB.These kinases phosphorylate the downstream effectors of the Hippo pathway,yes-associated protein(YAP),and transcriptional coactivator with PDZ-binding motif(TAZ),suppressing the expression of their downstream target genes.The Hippo signaling pathway kinase cascade plays a significant role in all cancers.Understanding the principles of this kinase cascade would prevent the occurrence of breast cancer.In recent years,small noncoding RNAs,or microRNAs,have been implicated in the development of several malignancies,including breast cancer.The interconnections between miRNAs and Hippo signaling pathway core proteins in the breast,on the other hand,remain poorly understood.In this review,we focused on highlighting the Hippo signaling system,its key parts,its importance in breast cancer,and its regulation by miRNAs and other related pathways.

YAP regulates the liver size during the fasting-refeeding transition in mice

Liver is the central hub regulating energy metabolism during feeding-fasting transition.Evidence suggests that fasting and refeeding induce dynamic changes in liver size,but the underlying mechanisms remain unclear.Yes-associated protein(YAP)is a key regulator of organ size.This study aims to explore the role of YAP in fasting-and refeeding-induced changes in liver size.Here,fasting significantly reduced liver size,which was recovered to the normal level after refeeding.Moreover,hepatocyte size was decreased and hepatocyte proliferation was inhibited after fasting.Conversely,refeeding promoted hepatocyte enlargement and proliferation compared to fasted state.Mechanistically,fasting or refeeding regulated the expression of YAP and its downstream targets,as well as the proliferation-related protein cyclin D1(CCND1).Furthermore,fasting significantly reduced the liver size in AAV-control mice,which was mitigated in AAV Yap(5SA)mice.Yap overexpression also prevented the effect of fasting on hepatocyte size and proliferation.Besides,the recovery of liver size after refeeding was delayed in AAV Yap shRNA mice.Yap knockdown attenuated refeeding-induced hepatocyte enlargement and proliferation.In summary,this study demonstrated that YAP plays an important role in dynamic changes of liver size during fasting-refeeding transition,which provides new evidence for YAP in regulating liver size under energy stress.

RAMP1 Protects Hepatocytes against Ischemia-reperfusion Injury by Inhibiting the ERK/YAP Pathway

Background and Aims:Hepatic ischemia-reperfusion injury(HIRI)is a prevalent complication of liver transplantation,partial hepatectomy,and severe infection,necessitating the development of more effective clinical strategies.Receptor activity–modifying protein 1(RAMP1),a member of the G protein–coupled receptor adapter family,has been implicated in numerous physiological and pathological processes.The study aimed to investigate the pathogenesis of RAMP1 in HIRI.Methods:We established a 70%liver ischemia-reperfusion model in RAMP1 knockout(KO)and wild-type mice.Liver and blood samples were collected after 0,6,and 24 h of hypoxia/reperfusion.Liver histological and serological analyses were performed to evaluate liver damage.We also conducted in-vitro and in-vivo experiments to explore the molecular mechanism underlying RAMP1 function.Results:Liver injury was exacerbated in RAMP1-KO mice compared with the sham group,as evidenced by increased cell death and elevated serum transaminase and inflammation levels.HIRI was promoted in RAMP1-KO mice via the induction of hepatocyte apoptosis and inhibition of proliferation.The absence of RAMP1 led to increased activation of the extracellular signal–regulated kinase(ERK)/mitogen-activated protein kinase(MAPK)pathway and yes-associated protein(YAP)phosphorylation,ultimately promoting apoptosis.SCH772984,an ERK/MAPK phosphorylation inhibitor,and PY-60,a YAP phosphorylation inhibitor,reduced apoptosis in in-vitro and in-vivo experiments.Conclusions:Our findings suggest that RAMP1 protects against HIRI by inhibiting ERK and YAP phosphorylation signal transduction,highlighting its potential as a therapeutic target for HIRI and providing a new avenue for intervention.

Regulation of ferroptosis in cancer cells by YAP/TAZ and Hippo pathways:The therapeutic implications

Ferroptosis is a novel form of iron-dependent cell death characterized by lipid per-oxidation.While the importance and disease relevance of ferroptosis is gaining recognition,much remains unknown about various genetic and non-genetic determinants of ferroptosis.Hippo signaling pathway is an evolutionarily conserved pathway that responds to various envi-ronmental cues and controls organ size,cell proliferation,death,and self-renewal capacity.In cancer biology,Hippo pathway is a potent tumor suppressing mechanism and its dysregulation contributes to apoptosis evasion,cancer development,metastasis,and treatment resistance.Hippo dysregulation leads to aberrant activation of YAP and TAZ,the two major transcription co-activators of TEADs,that induce the expression of genes triggering tumor-promoting pheno-types,including enhanced cell proliferation,self-renewal and apoptosis inhibition.The Hippo pathway is regulated by the cell-cell contact and cellular density/confluence.Recently,fer-roptosis has also been found being regulated by the cellular contact and density.The YAP/TAZ activation under low density,while confers apoptosis resistance,renders cancer cells sensitivity to ferroptosis.These findings establish YAP/TAZ and Hippo pathways as novel deter-minants of ferroptosis.Therefore,inducing ferroptosis may have therapeutic potential for YAP/TAZ-activated chemo-resistant and metastatic tumor cells.Reciprocally,various YAP/TAZ-targeting treatments under clinical development may confer ferroptosis resistance,limiting the therapeutic efficacy.