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.

LncRNA-ATB promotes autophagy by activating Yes-associated protein and inducing autophagy-related protein 5 expression in hepatocellular carcinoma

BACKGROUND Long non-coding RNAs (lncRNAs) play important roles in many diseases, including hepatocellular carcinoma (HCC). Autophagy is a metabolic pathway that facilitates cancer cell survival in response to stress. The relationship between autophagy and the lncRNA-activated by transforming growth factor beta (lncRNA-ATB) in HCC remains unknown. AIM To explore the influence of lncRNA-ATB in regulating autophagy in HCC cells and the underlying mechanism. METHODS In the present study, we evaluated lncRNA-ATB expression in tumor and adjacent non-tumor tissues from 72 HCC cases by real-time PCR. We evaluated the role of lncRNA-ATB in the proliferation and clonogenicity of HCC cells in vitro. The effect of lncRNA-ATB on autophagy was determined using a LC3-GFP reporter and transmission electron microscopy. Furthermore, the mechanism by which lncRNA-ATB regulates autophagy was explored by immunofluorescence staining, RNA immunoprecipitation (RIP), and Western blot. RESULTS The expression of lncRNA-ATB was higher in HCC tissues than in normal liver tissues, and lncRNA-ATB expression was positively correlated with tumor size, TNM stage, and poorer survival of patients with HCC. Moreover, ectopic overexpression of lncRNA-ATB promoted cell proliferation and clonogenicnity of HCC cells in vitro. LncRNA-ATB promoted autophagy by activating Yesassociated protein (YAP). Moreover, lncRNA-ATB interacted with autophagy-related protein 5 (ATG5) mRNA and increased ATG5 expression. CONCLUSION LncRNA-ATB regulates autophagy by activating YAP and increasing ATG5 expression. Our data demonstrate a novel function for lncRNA-ATB in autophagy and suggest that lncRNA-ATB plays an important role in HCC.

Central role of Yes-associated protein and WW-domain-containing transcriptional co-activator with PDZ-binding motif in pancreatic cancer development

Pancreatic ductal adenocarcinoma(PDAC) remains a deadly disease with no efficacious treatment options. PDAC incidence is projected to increase, which may be caused at least partially by the obesity epidemic. Significantly enhanced efforts to prevent or intercept this cancer are clearly warranted. Oncogenic KRAS mutations are recognized initiating events in PDAC development, however, they are not entirely sufficient for the development of fully invasive PDAC.Additional genetic alterations and/or environmental, nutritional, and metabolic signals, as present in obesity, type-2 diabetes mellitus, and inflammation, are required for full PDAC formation. We hypothesize that oncogenic KRAS increases the intensity and duration of the growth-promoting signaling network.Recent exciting studies from different laboratories indicate that the activity of the transcriptional co-activators Yes-associated protein(YAP) and WW-domaincontaining transcriptional co-activator with PDZ-binding motif(TAZ) play a critical role in the promotion and maintenance of PDAC operating as key downstream target of KRAS signaling. While initially thought to be primarily an effector of the tumor-suppressive Hippo pathway, more recent studies revealed that YAP/TAZ subcellular localization and co-transcriptional activity is regulated by multiple upstream signals. Overall, YAP has emerged as a central node of transcriptional convergence in growth-promoting signaling in PDAC cells. Indeed, YAP expression is an independent unfavorable prognostic marker for overall survival of PDAC. In what follows, we will review studies implicating YAP/TAZ in pancreatic cancer development and consider different approaches to target these transcriptional regulators.

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.

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.

Yes-associated protein at the intersection of liver cell fate determination

A recent publication highlights the importance of high yes-associated protein(YAP) expressing cells in liver regeneration following partial hepatectomy.Although the names of the cell populations described in these articles [hybrid periportal hepatocytes(HybHP) or epithelial-mesenchymal transition(EMT)-reprogrammed hepatocytes] are not identical, they all express high levels of YAP.We hypothesize that the HybHP and EMT-reprogrammed hepatocytes might be a similar cell population. Hippo signaling is the primary pathway that regulates YAP activity. According to the contribution of these two types of cells to liver regeneration and the high YAP expression, Hippo-YAP signaling activation may be a common regulatory pathway experienced by cells undergoing dedifferentiation and reactivating proliferative activity during liver regeneration.Although no evidence has shown that HybHP cells contribute to hepatocellular carcinoma in mouse models, we can not rule out the possibility that these highly regenerative cells can further develop into tumor cells when they acquire mutations caused by viral infection or other risk factors like alcohol. The detailed mechanistic insight of the regulation of YAP expression and activity in HybHP(or other types of cells contributing to liver regeneration) is unknown. We hypothesize that liver regeneration under various conditions will eventually lead to divergent consequences, likely due to the duration of YAP activation regulated by Hippo-large tumor suppressor 1 and 2 pathway in a context-and cell typedependent manner.

Association of Elevated Yes-Associated Protein Expression with Gastric Cancer and Its Clinicopathological Features: A Meta-Analysis

Objectives: To evaluate the difference of YAP-positive expression between GC and adjacent tissues, as well as the association of elevated YAP expression with clinicopathological features of GC. Methods: PubMed, Embase, Web of Science databases and the Chinese National Knowledge Infrastructure (CNKI) were searched from inception up to December 2018. The pooled ORs and corresponding 95% CIs were used to assess the strength of association. The heterogeneity among eligible studies was evaluated by the Q-test and I2 values. The sensitivity analysis was performed by sequential omission of individual studies. Moreover, Begg’s test and Egger’s test were used to evaluate publication bias. Results: A total of 2229 patients from 16 studies were included in this meta-analysis. The results showed that positive YAP expression was closely correlated with GC but not adjacent non-tumor tissue (OR = 8.08, 95% CI = 4.41 - 14.80). Additionally, YAP overexpression was found to be associated with more advanced TNM stage (OR = 2.68, 95% CI = 1.61 - 4.48), deeper invasion depth (OR = 2.05, 95% CI = 1.32 - 3.19), and lymph node metastasis (OR = 1.95, 95% CI = 1.29 - 2.96). No significant correlation was observed between YAP overexpression and degree of differentiation (OR = 1.17, 95% CI = 0.63 - 2.16), as well as gender of patients (OR = 1.12, 95% CI = 0.91 - 1.37) or tumor size (OR = 1.11, 95% CI = 0.82 - 1.49) of gastric cancer. Conclusions: This meta-analysis demonstrated that YAP might be a promising diagnostic marker and even a therapeutic target for gastric cancer.

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.

Constitutive androstane receptor induced-hepatomegaly and liver regeneration is partially via yes-associated protein activation

The constitutive androstane receptor(CAR, NR3 I1) belongs to nuclear receptor superfamily.It was reported that CAR agonist TCPOBOP induces hepatomegaly but the underlying mechanism remains largely unknown. Yes-associated protein(YAP) is a potent regulator of organ size. The aim of this study is to explore the role of YAP in CAR activation-induced hepatomegaly and liver regeneration.TCPOBOP-induced CAR activation on hepatomegaly and liver regeneration was evaluated in wildtype(WT) mice, liver-specific YAP-deficient mice, and partial hepatectomy(PHx) mice. The results demonstrate that TCPOBOP can increase the liver-to-body weight ratio in wild-type mice and PHx mice.Hepatocytes enlargement around central vein(CV) area was observed, meanwhile hepatocytesproliferation was promoted as evidenced by the increased number of KI67+cells around portal vein(PV)area. The protein levels of YAP and its downstream targets were upregulated in TCPOBOP-treated mice and YAP translocation can be induced by CAR activation. Co-immunoprecipitation results suggested a potential proteineprotein interaction of CAR and YAP. However, CAR activation-induced hepatomegaly can still be observed in liver-specific YAP-deficient(Yape/e) mice. In summary, CAR activation promotes hepatomegaly and liver regeneration partially by inducing YAP translocation and interaction with YAP signaling pathway, which provides new insights to further understand the physiological functions of CAR.

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.

Nuclear Dbf2-related Kinase 1 functions as tumor suppressor in glioblastoma by phosphorylation of Yes-associated protein

Background:The Nuclear Dbf2-related(NDR1)kinase is a member of the NDR/LATS family,which was a supplementary of Hippo pathway.However,whether NDR1 could inhibit glioblastoma(GBM)growth by phosphorylating Yes-associated protein(YAP)remains unknown.Meanwhile,the role of NDR1 in GBM was not clear.This study aimed to investigate the role of NDR1-YAP pathway in GBM.Methods:Bioinformation analysis and immunohistochemistry(IHC)were performed to identify the expression of NDR1 in GBM.The effect of NDR1 on cell proliferation and cell cycle was analyzed utilizing CCK-8,clone formation,immunofluorescence and flow cytometry,respectively.In addition,the xenograft tumor model was established as well.Protein interaction was examined by Coimmunoprecipitation and immunofluorescence to observe co-localization.Results:Bioinformation analysis and IHC of our patients’tumor tissues showed that expression of NDR1 in tumor tissue was relatively lower than that in normal tissues and was positively related to a lower survival rate.NDR1 could markedly reduce the proliferation and colony formation of U87 and U251.Furthermore,the results of flow cytometry showed that NDR1 led to cell cycle arrest at the G1 phase.Tumor growth was also inhibited in xenograft nude mouse models in NDR1-overexpression group.Western blotting and immunofluorescence showed that NDR1 could integrate with and phosphorylate YAP at S127 site.Meanwhile,NDR1 could mediate apoptosis process.Conclusion:In summary,our findings point out that NDR1 functions as a tumor suppressor in GBM.NDR1 is identified as a novel regulator of YAP,which gives us an in-depth comprehension of the Hippo signaling pathway.

Yes-associated protein contributes to magnesium alloy-derivedinflammation in endothelial cells

Magnesium alloy(Mg alloy)has attracted massive attention in the potential applications of cardiovascular stents because of its good biocompatibility and degradability.However,whether and how the Mg alloy induces inflammation in endothelial cells remains unclear.In the present work,we investigated the activation of Yes-associated protein(YAP)upon Mg alloy stimuli and unveiled the transcriptional function in Mg alloy-induced inflammation.Quantitative RT–PCR,western blotting and immunofluorescence staining showed that Mg alloy inhibited the Hippo pathway to facilitate nuclear shuttling and activation of YAP in human coronary artery endothelial cells(HCAECs).Chromatin immunoprecipitation followed sequencing was carried out to explore the transcriptional function of YAP in Mg alloy-derived inflammation.This led to the observation that nuclear YAP further bonded to the promoter region of inflammation transcription factors and co-transcription factors.This binding event activated their transcription and modified mRNA methylation of inflammation-related genes through regulating the expression of N6-methyladenosine modulators(METTL3,METTL14,FTO and WTAP).This then promoted inflammation-related gene expression and aggravated inflammation in HCAECs.In YAP deficiency cells,Mg alloy-induced inflammation was reduced.Collectively,our data suggest that YAP contributes to the Mg alloy-derived inflammation in HCAECs and may provide a potential therapeutic target that alleviates inflammation after Mg alloy stent implantation.

Nuclear Translocation and Activation of YAP by Hypoxia Contributes to Chemoresistance of SN38 in Hepatocellular Carcinoma Cells

Hypoxia was a prominent feature of hepatocellular carcinoma cells （HCC）, contributing to therapeutic resistance towards a variety chemotherapeutic agents including Topoisomerase I inhibitor SN38, with mechanism not yet fully understood, thus remaining a major clinical challenge. Herein, we present evidences that the hypoxia-in- duced nuclear translocation and accumulation of Yes-associated protein （YAP） acts as a survival input to promote hypoxic-resistance to SN38 in HCC. YAP induction by hypoxia was not mediated by HIF-lα, since the manipula- tion of HIF-1α either by COC12, exogenous expression nor siRNA of HIF-1α imposed any effect on the phosphoryla- tion or total level of YAP. Instead, mevalonate-HMG-CoA reductase （HMGCR） pathway may modulate the YAP pathway under hypoxia. Combined YAP inhibition by either siRNA or HMGCR inhibitor statins with SN38 achieved improved anti-cancer activities in HCC cells. Moreover, the increased anti-cancer efficacy of statins combined with irinotecan （the prodrug of SN-38 ） was further validated in a human HCC HepG2 xenografl model in nude mice. Taken together, our findings identify YAP as a novel mechanism of hypoxic-resistance to SN38. These results un- veil the combined suppression of YAP （ for instance , statins） and SN38 as a potential promising strategy to enhance treatment response of HCC patients, particularly those with advanced stage suffering from hypoxic resistance.

Inhibitory effects of dobutamine on human gastric adenocarcinoma

AIM:To explore the inhibitory effects of dobutamine on gastric adenocarcinoma cells.METHODS:Dobutamine was used to treat gastric adenocarcinoma cells(SGC-7901)and cell viability was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT)assay.The effects of dobutamine combined with cisplatin on cell viability were also analyzed.Cell migration was studied using the wound healing assay,and cell proliferation was analyzed using the colony formation assay.A cell invasion assay was carried out using Transwell cell culture chambers.The cell cycle and cell apoptosis were analyzed by flow cytometry.Western blot and immunocytochemistry were performed to determine the expression of Yes-associated protein(YAP)in treated cells.RESULTS:Dobutamine significantly inhibited cell growth,migration,cell colony formation,and cell invasion into Matrigel.Dobutamine also arrested the cell cycle at G1/S phase,and increased the rate of apoptosis of gastric adenocarcinoma cells.The expression ofYAP was detected mainly in the nucleus in the absence of dobutamine.However,reduced expression of phosphorylated YAP was mainly found in the cytosol following treatment with dobutamine.CONCLUSION:Dobutamine has significant inhibitory effects on gastric adenocarcinoma cells and may be used in neoadjuvant therapy not only for gastric cancer,but also for other tumors.

Pien Tze Huang Inhibits Migration and Invasion of Hepatocellular Carcinoma Cells by Repressing PDGFRB/YAP/CCN2 Axis Activity

Objective:To investigate the effects of Pien Tze Huang(PZH) on the migration and invasion of HCC cells and underlying molecular mechanism.Methods:Cell counting kit-8(CCK-8) was applied to evaluate the cell viabilities of SMMC-7721,SK-Hep-1,C3A and HL-7702(6 × 10^(3)cells/well) co-incubated with different concentrations of PZH(0,0.2,0.4,0.6,0.8 mg/mL) for 24 h.Transwell,wound healing assay,CCK-8and Annexin V-FITC/PI staining were conducted to investigate the effects of PZH on the migration,invasion,proliferation and apoptosis of SK-Hep-1 and SMMC-7721 cells(650 μg/mL for SK-Hep-1 cells and 330 μg/mL for SMMC-7721 cells),respectively.In vivo,lung metastasis mouse model constructed by tail vein injection of HCC cells was used for evaluating the anti-metastasis function of PZH.SK-Hep-1 cells(10^(6)cells/200 μL per mice) were injected into B-NDG mice via tail vein.Totally 8 mice were randomly divided into PZH and control groups,4 mice in each group.After 2-d inoculation,mice in the PZH group were administered with PZH(250 mg/kg,daily) and mice in the control group received only vehicle(PBS) from the 2nd day after xenograft to day 17.Transcriptome analysis based on RNA-seq was subsequently used for deciphering anti-tumor mechanism of PZH.Quantitative real-time polymerase chain reaction(qRT-PCR) and Western blot were applied to verify RNA-seq results.Luciferase reporter assay was performed to examine the transcriptional activity of yes-associated protein(YAP).Results:PZH treatment significantly inhibited the migration,invasion,proliferation and promoted the apoptosis of HCC cells in vitro and in vivo(P<0.01).Transcriptome analysis indicated that Hippo signaling pathway was associated with anti-metastasis function of PZH.Mechanical study showed PZH significantly inhibited the expressions of platelet derived growth factor receptor beta(PDGFRB),YAP,connective tissue growth factor(CCN2),N-cadherin,vimentin and matrix metallopeptidase 2(MMP2,P<0.01).Meanwhile,the phosphorylation of YAP was also enhanced by PZH treatment in vitro and in vivo.Furthermore,PZH played roles in inhibiting the transcriptional activity of YAP.Conclusion:PZH restrained migration,invasion and epithelialmesenchymal transition of HCC cells through repressing PDGFRB/YAP/CCN2 axis.

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.

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.

Adaptable hydrogel with reversible linkages for regenerative medicine:Dynamic mechanical microenvironment for cells

Hydrogels are three-dimensional platforms that serve as substitutes for native extracellular matrix.These materials are starting to play important roles in regenerative medicine because of their similarities to native matrix in water content and flexibility.It would be very advantagoues for researchers to be able to regulate cell behavior and fate with specific hydrogels that have tunable mechanical properties as biophysical cues.Recent developments in dynamic chemistry have yielded designs of adaptable hydrogels that mimic dynamic nature of extracellular matrix.The current review provides a comprehensive overview for adaptable hydrogel in regenerative medicine as follows.First,we outline strategies to design adaptable hydrogel network with reversible linkages according to previous findings in supramolecular chemistry and dynamic covalent chemistry.Next,we describe the mechanism of dynamic mechanical microenvironment influence cell behaviors and fate,including how stress relaxation influences on cell behavior and how mechanosignals regulate matrix remodeling.Finally,we highlight techniques such as bioprinting which utilize adaptable hydrogel in regenerative medicine.We conclude by discussing the limitations and challenges for adaptable hydrogel,and we present perspectives for future studies.

Structural and functional insights into the TEAD-YAP complex in the Hippo signaling pathway

The control of organ size growth is one of the most fundamental aspects of life.In the past two decades,a highly conserved Hippo signaling pathway has been identified as a key molecular mechanism for governing organ size regulation.In the middle of this pathway is a kinase cascade that negatively regulates the downstream component Yes-associated protein(YAP)/transcriptional coactivator with PDZ-binding motif(TAZ)/Yorkie through phosphorylation.Phosphorylation of YAP/TAZ/Yorkie promotes its cytoplasmic localization,leads to cell apoptosis and restricts organ size overgrowth.When the Hippo pathway is inactivated,YAP/TAZ/Yorkie translocates into the nucleus to bind to the transcription enhancer factor(TEAD/TEF)family of transcriptional factors to promote cell growth and proliferation.In this review,we will focus on the structural and functional studies on the downstream transcription factor TEAD and its coactivator YAP.