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Cervical cancer is a leading cause of cancer-related death among women and its recurrence and metastasis poses challenges to treatment. Discoidin domain receptor 1 (DDR1) was associated with cellular migration and invasion in several types of cancers. However, its function in cervical cancer is still unclear. In this study, we found that DDR1 was significantly more expressed in cervical cancer samples than in normal tissues. SRY-Box transcription factor 2 (SOX2), a known oncogene in cervical cancer, showed a positive correlation with DDR1 and regulated DDR1 transcription, contributing to the elevated expression of DDR1 in cervical cancer. Regarding the function of DDR1 in cervical cancer, the overexpression of DDR1 caused an increase in the migration, invasion, and epithelial-mesenchymal transition (EMT) of cervical cancer cells. In contrast, cervical cancer cells with reduced DDR1 expression exhibited a lower migration rate, fewer invasive cells, and decreased levels of EMT markers. In vivo, mice injected with cervical cancer cells with overexpressed DDR1 showed more pulmonary metastasis and nodule number. Opposite results were found in mice injected with DDR1 silenced cervical cancer cells. Since DDR1 can cause phosphorylation of downstream targets, a phosphorylation omics was employed to reveal the downstream targets of DDR1, including eukaryotic translation initiation factor 4E binding protein 1 and EPH receptor A2. Furthermore, DDR1 bound directly with Src homology 2 domain of growth factor receptor bound protein 2 (GRB2) which mediated the function of DDR1 in the malignant behaviors of cervical cancer and the phosphorylation of downstream targets. In conclusion, DDR1 binds directly to GRB2 and then affects downstream phosphorylation signals, ultimately exacerbating the metastasis of cervical cancer cells. This work sheds light on the mechanism by which DDR1 functions in cervical cancer cells, providing therapeutic strategy for the treatment of cervical cancer., Competing Interests: Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Drug resistance remains a challenge for targeted therapy of cancers driven by EML4-ALK and related fusion oncogenes. EML4-ALK forms cytoplasmic protein condensates, which result from networks of interactions between oncogene and adapter protein multimers. While these assemblies are associated with oncogenic signaling, their role in drug response is unclear. Here, we use optogenetics and live-cell imaging to find that EML4-ALK assemblies suppress transmembrane receptor tyrosine kinase (RTK) signaling by sequestering RTK adapter proteins including GRB2 and SOS1. Furthermore, ALK inhibition, while suppressing oncogenic signaling, simultaneously releases the sequestered adapters and thereby resensitizes RTK signaling. Resensitized RTKs promote rapid and pulsatile ERK reactivation that originates from paracrine ligands shed by dying cells. Reactivated ERK signaling promotes cell survival, which can be counteracted by combination therapies that block paracrine signaling. Our results identify a regulatory role for RTK fusion assemblies and uncover a mechanism of tolerance to targeted therapies., (© 2024. The Author(s).)

A wide range of cells respond to fibroblast growth factor 2 (FGF2) by proliferation via activation of the Ras/ERK1/2 pathway. In this study, the potential involvement of salt inducible kinase SIK2) in this cascade within retinal Müller glia is explored. It is found that SIK2 phosphorylation status and activity are modulated in an FGF2-dependent manner, possibly via ERK1/2. With SIK2 downregulation, enhanced ERK1/2 activation with delayed attenuation and increased cell proliferation is observed, while SIK2 overexpression hampers FGF2-dependent ERK1/2 activation. In vitro kinase and site-directed mutagenesis studies indicate that SIK2 targets the pathway element GRB2-associated-binding protein 1 (Gab1) on Ser266. This phosphorylation event weakens Gab1 interactions with its partners growth factor receptor-bound protein 2 (Grb2) and Src homology region 2 domain containing phosphatase 2 (Shp2). Collectively, these results suggest that during FGF2-dependent proliferation process ERK1/2-mediated activation of SIK2 targets Gab1, resulting in downregulation of the Ras/ERK1/2 cascade in a feedback loop., (© 2024 Wiley‐VCH GmbH.)

The Growth factor receptor-bound protein 2 (Grb2) participates in early signaling complexes and regulates tyrosine kinase-mediated signal transduction through a monomer-dimer equilibrium. Grb2 dimeric state inhibits signal transduction whereas the monomer promotes signaling downstream. Since Grb2 dimer K D is ∼0.8 μM, studies focused on the monomer are still challenging and require mutations or interaction with phosphotyrosine peptides. However, these mutants were never characterized considering their effects on protein structure and dynamics in solution. Here, we present the biophysical characterization of Grb2 Y160F , the first Grb2 mutant to induce protein monomerization without disrupting its native behavior in solution due to net charge modifications or interaction with peptides. We also identified that Grb2 Y160F exists in a monomer-dimer equilibrium. Grb2 Y160F ability to dimerize implies that different dimerization interfaces might regulate signaling pathways in distinct ways and raises an important question about the role of the Y160 residue in other dimerization interfaces., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper as potential competing interests., (Copyright © 2024. Published by Elsevier B.V.)

RHOV and RHOU are considered atypical Rho-family small GTPases because of the existence of N- and C-terminal extension regions, abnormal GDP/GTP cycling, and post-translational modification. Particularly, RHOV and RHOU both have a proline-rich (PR) motif in the N-terminal region. It has been reported that the PR motif of RHOU interacts with GRB2, a SH3 domain-containing adaptor protein, and regulates its activity through EGF receptor signaling. However, it is unknown whether RHOV, like RHOU, interacts with SH3 domain-containing adaptor proteins. In this study, we investigated the interactions between RHOV and SH3 domain-containing adaptor proteins, including GRB2 and NCK2. The RHOV-induced serum response factor (SRF)-dependent gene transcriptional activity was attenuated in cells co-expressing either GRB2 or NCK2 compared to cells expressing RHOV alone. From the results of experiments using various gene mutants of RHOV and GRB2, it appears that the PR motif of the N-terminal region of RHOV is the crucial binding site for the SH3 domain-containing proteins. Furthermore, we found that Ser25 in the N-terminal region of RHOV is phosphorylated by PKA and that its phosphorylation is suppressed by interaction with NCK2 but not GRB2. We have found a novel regulatory mechanism for the phosphorylation of RHOV and its interaction with SH3 domain-containing adaptor proteins., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Regulating cardiolipin to maintain mitochondrial homeostasis is a promising strategy for addressing Parkinson's disease (PD). Through a comprehensive screening and validation process involving multiple models, ginsenoside Rg3 (Rg3) as a compound capable of enhancing cardiolipin levels is identified. This augmentation in cardiolipin levels fosters mitochondrial homeostasis by bolstering mitochondrial unfolded protein response, promoting mitophagy, and enhancing mitochondrial oxidative phosphorylation. Consequently, this cascade enhances the survival of tyrosine hydroxylase positive (TH + ) dopaminergic neurons, leading to an amelioration in motor performance within PD mouse models. Using limited proteolysis-small-molecule mapping combined with molecular docking analysis, it has confirmed Growth Factor Receptor-Bound Protein 2 (GRB2) as a molecular target for Rg3. Furthermore, these investigations reveal that Rg3 facilitates the interaction between GRB2 and TRKA (Neurotrophic Tyrosine Kinase, Receptor, Type 1), thus promotes EVI1 (Ecotropic Virus Integration Site 1 Protein Homolog) phosphorylation by ERK, subsequently increases CRLS1 (Cardiolipin Synthase 1) gene expression and boosts cardiolipin synthesis. The absence of GRB2 or CRLS1 significantly attenuates the beneficial effects of Rg3 on PD symptoms. Finally, Tenofovir Disoproxil Fumarate (TDF) that also promotes the binding between GRB2 and TRKA is further identified. The identified compounds, Rg3 and TDF, exhibit promising potential for the prevention of PD by bolstering cardiolipin expression and reinstating mitochondrial homeostasis., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

The transforming growth factor-β (TGF-β) signaling pathway is pivotal in inducing epithelial-mesenchymal transition (EMT) and promoting cancer metastasis. Long non-coding RNAs (lncRNAs) have emerged as significant players in these processes, yet their precise mechanisms remain elusive. Here, we demonstrate that TGF-β-upregulated lncRNA 1 (TBUR1) is significantly activated by TGF-β via Smad3/4 signaling in lung adenocarcinoma (LUAD) cells. Functionally, TBUR1 triggers EMT, enhances LUAD cell migration and invasion in vitro, and promotes metastasis in nude mice. Mechanistically, TBUR1 interacts with heterogeneous nuclear ribonucleoprotein C (hnRNPC) to stabilize GRB2 mRNA in an m 6 A-dependent manner. Clinically, TBUR1 is upregulated in LUAD tissues and correlates with poor prognosis, highlighting its potential as a prognostic biomarker and therapeutic target for LUAD. Taken together, our findings underscore the crucial role of TBUR1 in mediating TGF-β-induced EMT and metastasis in LUAD, providing insights for future therapeutic interventions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Growth factor receptor-bound protein 2 (GRB2) is a negative regulator of insulin signaling and a positive regulator of angiogenesis. Its expression is increased in a mouse model of retinal neovascularization and in patients with type 2 diabetes mellitus (T2DM). This case-control study aimed to investigate the association between the rs9896052 polymorphism (A>C) upstream of GRB2 and proliferative diabetic retinopathy (PDR) in patients with T2DM from Southern Brazil, taking into consideration self-reported skin color (white or non-white) and the known duration of diabetes (<10 years or ≥10 years). Genotypes were determined by real-time PCR in 838 patients with T2DM (284 cases with PDR and 554 controls without DR). In the total study group and in the analysis stratified by skin color, the genotype and allele frequencies were similar between cases and controls. However, among patients with less than 10 years of diabetes, the C allele was more frequent in cases than in controls (63.3% versus 51.8%, p = 0.032), and the CC genotype was independently associated with an increased risk of PDR (adjusted OR = 2.82, 95% CI 1.17-6.75). In conclusion, our findings support the hypothesis that the rs9896052 polymorphism near GRB2 is associated with PDR in Brazilian patients with T2DM.

Objective: Limited research has focused on the role of dihydrouridine synthases (DUS) family members in human tumors. Our previous findings indicated an impact of dihydrouridine synthase 4 like (DUS4L) on cell proliferation and apoptosis in lung adenocarcinoma (LUAD) A549 cell, yet its broader functions and regulatory mechanisms in LUAD remain elusive., Methods: Using a LUAD tissue microarray and immunohistochemical (IHC) staining, we validated variations in DUS4L protein expression levels among LUAD patients and assessed its clinical significance. Additional experiments using short hairpin RNA (shRNA) against DUS4L (sh-DUS4L-2), LUAD cell lines, cell function assays (including wound healing, transwell migration and invasion, colony formation, and apoptosis assays), and mouse tumor xenografts were performed to examine the biological roles of DUS4L in LUAD progression. RNA sequencing, proteomic analyses, mass spectrometry, and co-immunoprecipitation experiments were conducted to identify and validate DUS4L-regulated downstream target genes and signaling pathways., Results: We identified a consistent upregulation of DUS4L in LUAD tissues. In vitro and in vivo experiments underscored the inhibitory effect of DUS4L downregulation on LUAD progression, including migration, invasion, and proliferation. Mechanistically, DUS4L was found to interact with the signaling molecule GRB2, promoting LUAD progression and metastasis by inducing epithelial-mesenchymal transition (EMT) via the PI3K/AKT and ERK/MAPK pathways., Conclusion: Our results establish the functional role of DUS4L in driving the progression and metastasis of LUAD, implicating its potential as a candidate therapeutic target for LUAD., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Avian reovirus (ARV) is a significant pathogen that causes various clinical diseases in chickens, including viral arthritis, chronic respiratory diseases, retarded growth, and malabsorption syndrome. These conditions result in substantial economic losses for the global poultry industry. MicroRNAs (miRNAs), a type of small noncoding RNAs that regulate gene expression post transcriptionally by silencing or degrading their RNA targets, play crucial roles in response to pathogenic infections. In this study, transfection of DF-1 cells with gga-miR-200a-3p, an upregulated miRNA observed in ARV-infected cells, significantly suppressed ARV-induced apoptosis by directly targeting GRB2 and impeded ARV replication. Conversely, knockdown of endogenous gga-miR-200a-3p in DF-1 cells using a specific miRNA inhibitor enhanced ARV-induced apoptosis and promoted GRB2 expression, thereby facilitating viral growth within cells. Consistently, inhibition of GRB2 activity through siRNA-mediated knockdown reduced viral titers. Therefore, gga-miR-200a-3p plays a vital antiviral role in the host response to ARV infection by suppressing apoptosis via direct targeting of GRB2 protein. This information enhances our understanding of the mechanisms by which host cells combat against ARV infection through self-encoded small RNA molecules and expands our knowledge regarding the involvement of microRNAs in the host response to pathogenic infections., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Yongqiang Wang reports financial support was provided by National Natural Science Foundation of China and Earmarked Fund for Modern Agro-Industry Technology Research System of China. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Porcine deltacoronavirus (PDCoV), an enteropathogenic coronavirus, causes severe watery diarrhoea, dehydration and high mortality in piglets, which has the potential for cross-species transmission in recent years. Growth factor receptor-bound protein 2 (Grb2) is a bridging protein that can couple cell surface receptors with intracellular signal transduction events. Here, we investigated the reciprocal regulation between Grb2 and PDCoV. It is found that Grb2 regulates PDCoV infection and promotes IFN-β production through activating Raf/MEK/ERK/STAT3 pathway signalling in PDCoV-infected swine testis cells to suppress viral replication. PDCoV N is capable of interacting with Grb2. The proline-rich motifs in the N- or C-terminal region of PDCoV N were critical for the interaction between PDCoV-N and Grb2. Except for Deltacoronavirus PDCoV N, the Alphacoronavirus PEDV N protein could interact with Grb2 and affect the regulation of PEDV replication, while the N protein of Betacoronavirus PHEV and Gammacoronavirus AIBV could not interact with Grb2. PDCoV N promotes Grb2 degradation by K48- and K63-linked ubiquitin-proteasome pathways. Overexpression of PDCoV N impaired the Grb2-mediated activated effect on the Raf/MEK/ERK/STAT3 signal pathway. Thus, our study reveals a novel mechanism of how host protein Grb2 protein regulates viral replication and how PDCoV N escaped natural immunity by interacting with Grb2.

Background: Programmed cell death is an important mechanism for the development of hepatic ischemia and reperfusion (IR) injury, and multiple novel forms of programmed cell death are involved in the pathological process of hepatic IR. ERRFI1 is involved in the regulation of cell apoptosis in myocardial IR. However, the function of ERRFI1 in hepatic IR injury and its modulation of programmed cell death remain largely unknown., Methods: Here, we performed functional and molecular mechanism studies in hepatocyte-specific knockout mice and ERRFI1-silenced hepatocytes to investigate the significance of ERRFI1 in hepatic IR injury. The histological severity of livers, enzyme activities, hepatocyte apoptosis and ferroptosis were determined., Results: ERRFI1 expression increased in liver tissues from mice with IR injury and hepatocytes under oxygen-glucose deprivation/reoxygenation (OGD/R) conditions. Hepatocyte-specific ERRFI1 knockout alleviated IR-induced liver injury in mice by reducing cell apoptosis and ferroptosis. ERRFI1 knockdown reduced apoptotic and ferroptotic hepatocytes induced by OGD/R. Mechanistically, ERRFI1 interacted with GRB2 to maintain its stability by hindering its proteasomal degradation. Overexpression of GRB2 abrogated the effects of ERRFI1 silencing on hepatocyte apoptosis and ferroptosis., Conclusions: Our results revealed that the ERRFI1-GRB2 interaction and GRB2 stability are essential for ERRFI1-regulated hepatic IR injury, indicating that inhibition of ERRFI1 or blockade of the ERRFI1-GRB2 interaction may be potential therapeutic strategies in response to hepatic IR injury., (© 2024. The Author(s).)

Rearranged during transfection (RET) rearrangement oncoprotein-mediated Ras/MAPK signaling cascade is constitutively activated in cancers. Here, we demonstrate a unique signal niche. The niche is a ternary complex based on the chimeric RET liquid-liquid phase separation. The complex comprises the rearranged kinase (RET fusion); the adaptor (GRB2), and the effector (SHC1). Together, they orchestrate the Ras/MAPK signal cascade, which is dependent on tyrosine kinase. CCDC6-RET fusion undergoes LLPS requiring its kinase domain and its fusion partner. The CCDC6-RET fusion LLPS promotes the autophosphorylation of RET fusion, with enhanced kinase activity, which is necessary for the formation of the signaling niche. Within the signal niche, the interactions among the constituent components are reinforced, and the signal transduction efficiency is amplified. The specific RET fusion-related signal niche elucidates the mechanism of the constitutive activation of the Ras/MAPK signaling pathway. Beyond just focusing on RET fusion itself, exploration of the ternary complex potentially unveils a promising avenue for devising therapeutic strategies aimed at treating RET fusion-driven diseases., Competing Interests: Competing interests statement:The authors declare no competing interest.

The adaptor protein Grb2, or growth factor receptor-bound protein 2, possesses a pivotal role in the transmission of fundamental molecular signals in the cell. Despite lacking enzymatic activity, Grb2 functions as a dynamic assembly platform, orchestrating intracellular signals through its modular structure. This study delves into the energetic communication of Grb2 domains, focusing on the folding and binding properties of the C-SH3 domain linked to its neighboring SH2 domain. Surprisingly, while the folding and stability of C-SH3 remain robust and unaffected by SH2 presence, significant differences emerge in the binding properties when considered within the tandem context compared with isolated C-SH3. Through a double mutant cycle analysis, we highlighted a subset of residues, located at the interface with the SH2 domain and far from the binding site, finely regulating the binding of a peptide mimicking a physiological ligand of the C-SH3 domain. Our results have mechanistic implications about the mechanisms of specificity of the C-SH3 domain, indicating that the presence of the SH2 domain optimizes binding to its physiological target, and emphasizing the general importance of considering supramodular multidomain protein structures to understand the functional intricacies of protein-protein interaction domains., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Growth factor receptor-bound protein 2 (GRB2) is a cytoplasmic adapter for tyrosine kinase signaling and a nuclear adapter for homology-directed-DNA repair. Here we find nuclear GRB2 protects DNA at stalled replication forks from MRE11-mediated degradation in the BRCA2 replication fork protection axis. Mechanistically, GRB2 binds and inhibits RAD51 ATPase activity to stabilize RAD51 on stalled replication forks. In GRB2-depleted cells, PARP inhibitor (PARPi) treatment releases DNA fragments from stalled forks into the cytoplasm that activate the cGAS-STING pathway to trigger pro-inflammatory cytokine production. Moreover in a syngeneic mouse metastatic ovarian cancer model, GRB2 depletion in the context of PARPi treatment reduced tumor burden and enabled high survival consistent with immune suppression of cancer growth. Collective findings unveil GRB2 function and mechanism for fork protection in the BRCA2-RAD51-MRE11 axis and suggest GRB2 as a potential therapeutic target and an enabling predictive biomarker for patient selection for PARPi and immunotherapy combination., (© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

FGF activation is known to engage canonical signals, including ERK/MAPK and PI3K/AKT, through various effectors including FRS2 and GRB2. Fgfr2FCPG/FCPG mutants that abrogate canonical intracellular signaling exhibit a range of mild phenotypes but are viable, in contrast to embryonic lethal Fgfr2-/- mutants. GRB2 has been reported to interact with FGFR2 through a non-traditional mechanism, by binding to the C-terminus of FGFR2 independently of FRS2 recruitment. To investigate whether this interaction provides functionality beyond canonical signaling, we generated mutant mice harboring a C-terminal truncation (T). We found that Fgfr2T/T mice are viable and have no distinguishable phenotype, indicating that GRB2 binding to the C-terminal end of FGFR2 is not required for development or adult homeostasis. We further introduced the T mutation on the sensitized FCPG background but found that Fgfr2FCPGT/FCPGT mutants did not exhibit significantly more severe phenotypes. We therefore conclude that, although GRB2 can bind to FGFR2 independently of FRS2, this binding does not have a critical role in development or homeostasis., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2023. Published by The Company of Biologists Ltd.)

Protein interactions with the microRNA (miRNA)-mediated gene silencing protein Argonaute 2 (AGO2) control miRNA expression. miRNA biogenesis starts with the production of precursor transcripts and culminates with the loading of mature miRNA onto AGO2 by DICER1. Here we reveal an additional component to the regulatory mechanism for miRNA biogenesis involving the adaptor protein, growth factor receptor-bound protein 2 (GRB2). The N-terminal SH3 domain of GRB2 is recruited to the PAZ domain of AGO2 forming a ternary complex containing GRB2, AGO2 and DICER1. Using small-RNA sequencing we identified two groups of miRNAs which are regulated by the binding of GRB2. First, mature and precursor transcripts of mir-17~92 and mir-221 miRNAs are enhanced. Second, mature, but not precursor, let-7 family miRNAs are diminished suggesting that GRB2 directly affects loading of these miRNAs. Notably, the resulting loss of let-7 augments expression of oncogenic targets such as RAS. Thus, a new role for GRB2 is established with implications for cancer pathogenesis through regulation of miRNA biogenesis and oncogene expression., (© 2023. The Author(s).)

GRB2 is an adaptor protein required for facilitating cytoplasmic signaling complexes from a wide array of binding partners. GRB2 has been reported to exist in either a monomeric or dimeric state in crystal and solution. GRB2 dimers are formed by the exchange of protein segments between domains, otherwise known as "domain-swapping". Swapping has been described between SH2 and C-terminal SH3 domains in the full-length structure of GRB2 (SH2/C-SH3 domain-swapped dimer), as well as between α-helixes in isolated GRB2 SH2 domains (SH2/SH2 domain-swapped dimer). Interestingly, SH2/SH2 domain-swapping has not been observed within the full-length protein, nor have the functional influences of this novel oligomeric conformation been explored. We herein generated a model of full-length GRB2 dimer with an SH2/SH2 domain-swapped conformation supported by in-line SEC-MALS-SAXS analyses. This conformation is consistent with the previously reported truncated GRB2 SH2/SH2 domain-swapped dimer but different from the previously reported, full-length SH2/C-terminal SH3 (C-SH3) domain-swapped dimer. Our model is also validated by several novel full-length GRB2 mutants that favor either a monomeric or a dimeric state through mutations within the SH2 domain that abrogate or promote SH2/SH2 domain-swapping. GRB2 knockdown and re-expression of selected monomeric and dimeric mutants in a T cell lymphoma cell line led to notable defects in clustering of the adaptor protein LAT and IL-2 release in response to TCR stimulation. These results mirrored similarly-impaired IL-2 release in GRB2-deficient cells. These studies show that a novel dimeric GRB2 conformation with domain-swapping between SH2 domains and monomer/dimer transitions are critical for GRB2 to facilitate early signaling complexes in human T cells., (© 2023. The Author(s).)

Malignant melanoma is the most aggressive form of skin cancer, and it is characterized by poor prognosis in patients with metastatic diseases. Accurate prediction of prognosis is crucial for therapeutic decisions. In this study, bioinformatics analysis was used to explore the prognostic value of growth factor receptor-bound protein 2-associated binding protein 3 (GAB3) mRNA. RNA transcriptome sequencing data and clinical data from The Cancer Genome Atlas and genotype-tissue expression (GTEx) were analyzed for differentially expressed genes in high and low GAB3 mRNA expression groups in melanoma. Performing gene enrichment analysis and constructing protein-protein interaction networks. High expression of GAB3 was significantly correlated with a lower T stage, melanoma Clark level, Breslow depth, and melanoma ulceration. And high GAB3 expression was also associated with better progression-free interval in T1 and T2 stages and N0 stage and longer overall survival in T1 and T2 stages, N0 stage, and N1 stage. GAB3 promoted high levels of infiltration of macrophages and activated natural killer cells in melanoma. High expression of GAB3 predicted a positive prognosis in early-stage melanoma that may be mediated by the anticancer immune response., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Non-small cell lung cancer (NSCLC) is associated with high morbidity and mortality. Dysregulation of lncRNAs leads to NSCLC progression., Objective: This study aims to explore the regulatory mechanism of lncRNA LINC01234 in NSCLC., Materials and Methods: LINC01234 expression in NSCLC cells was determined. Cell proliferation was detected using CCK-8, colony formation, and EDU assays after transfection of siRNA LINC01234 into H1299 cells and transfection of pcDNA3.1-LINC01234 into H1975 cells. Subcellular localization of LINC01234 was predicted and the binding relations between LINC01234 and miR-433-3p as well as miR-433-3p and GRB2 were verified. The expression levels of miR-433-3p and GRB2 in NSCLC cells were determined. Joint experiments of miR-433-3p inhibitor + si- LINC01234-1 or oe-GRB2 + si-LINC01234-1 were conducted to verify the role of miR-433-3p and GRB2 in NSCLC cell malignant proliferation., Results: LINC01234 was abundantly expressed in NSCLC cells. LINC01234 silencing reduced NSCLC cell proliferation while LINC01234 overexpression enhanced cell proliferation. LINC01234 competitively bound to miR-433-3p and miR-433-3p directly targeted GRB2. miR- 433-3p knockdown or GRB2 overexpression counteracted the repressive effect of LINC01234 silencing on NSCLC cell malignant proliferation., Conclusion: LINC01234 competitively bound to miR-433-3p and promoted GRB2 transcription to augment NSCLC cell malignant proliferation., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Background: Endometriosis is a common gynecological condition with a substantial economic burden on society. It is known that both genetic and environmental factors are contributing to the phenotypic development of the disease. MicroRNAs have a vital role in the pathogenesis of endometriosis. miR-1271 and its direct target gene, GRB2 (growth factor receptor-bound protein 2), expression have been studied in gynecologic cancers, while their role in endometriosis has not been studied., Objective: We measured miR-1271 and GRB2 gene expression in the eutopic and ectopic tissues of patients (endometrial tissues) in contrast to the control samples from healthy women., Materials and Methods: In this study, a total of 45 samples (15 control samples, 15 eutopic samples and 15 ectopic samples) were collected. We used qRT-PCR (quantitative polymerase chain reaction) to evaluate the expression levels of the miR-1271 and GRB2 gene., Results: We observed inverse expression of miR-1271 and GRB2 gene. MiR-1271 expression was significantly reduced in patients with endometriosis compared with healthy women. While there was a noticeable increase in the expression level of its target gene, GRB2, in tissues of endometriosis patients compared with normal control samples., Conclusion: We have shown an inverse relationship between the reduction of miR-1271 expression level and increase in the expression level of GRB2, therefore, increased GRB2 expression in endometriosis tissues can be due to decreased expression of this microRNA. Our findings suggested that miR-1271 maybe play a role as a biomarker in the diagnosis of patients with endometriosis., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier B.V.)

Activation of RAS is crucial in driving cellular outcomes including proliferation, differentiation, migration and apoptosis via the MAPK pathway. This is initiated on recruitment of Grb2, as part of a Grb2-Sos complex, to an up-regulated receptor tyrosine kinase (RTK), enabling subsequent interaction of Sos with the plasma membrane-localised RAS. Aberrant regulation at this convergence point for RTKs in MAPK signalling is a key driver of multiple cancers. Splicing of the GRB2 gene produces a deletion variant, Grb3-3, that is incapable of binding to RTKs. We show that, despite maintaining the ability to bind to Sos, the Grb3-3-Sos complex remains in the cytoplasm, unable to engage with RAS. Competition between Grb2 and Grb3-3 for binding to C-terminal proline-rich sequences on Sos modulates MAPK signalling. Additionally, we demonstrate that splicing is regulated by heterogenous nuclear riboproteins C1/C2, and that normal and malignant colon tissue show differential Grb3-3 expression., (© 2022. The Author(s).)

Loss of muscle mass can lead to diseases such as sarcopenia, diabetes, and obesity, which can worsen the quality of life and increase the incidence of disease. Therefore, understanding the mechanism underlying skeletal muscle differentiation is vital to prevent muscle diseases. We previously found that microRNA-320 (miR-320) is highly expressed in the lean muscle-type pigs, but its regulatory role in myogenesis remains unclear. The bioinformatics prediction indicated that miR-320 could bind to the 3 'untranslated region of growth factor receptor-bound protein-2 (Grb2). We hypothesized that miR-320 targets Grb2 to regulate myoblasts differentiation. To verify this, we transfected miR-320 mimic and inhibitor into C2C12 myoblasts to assess the role of miR-320 during myoblasts differentiation. We used real-time qPCR, luciferase reporter assays, and western blotting to confirm that miR-320 directly targets Grb2 to promote myoblasts differentiation. Moreover, by using a dexamethasone-induced atrophic model of myotubes, we discovered that miR-320 promotes the repair of damaged myotubes. Our findings expand understanding of miRNAs and genes related to regulating skeletal muscle differentiation, and provide insight into underlying therapeutic strategies for muscle diseases., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Translocation of Fibroblast Growth Factor Receptors (FGFRs) often leads to aberrant cell proliferation and cancer. The BCR-FGFR1 fusion protein, created by chromosomal translocation t(8;22)(p11;q11), contains Breakpoint Cluster Region (BCR) joined to Fibroblast Growth Factor Receptor 1 (FGFR1). BCR-FGFR1 represents a significant driver of 8p11 myeloproliferative syndrome, or stem cell leukemia/lymphoma, which progresses to acute myeloid leukemia or T-cell lymphoblastic leukemia/lymphoma. Mutations were introduced at Y177F, the binding site for adapter protein Grb2 within BCR; and at Y766F, the binding site for the membrane associated enzyme PLCγ1 within FGFR1. We examined anchorage-independent cell growth, overall cell proliferation using hematopoietic cells, and activation of downstream signaling pathways. BCR-FGFR1-induced changes in protein phosphorylation, binding partners, and signaling pathways were dissected using quantitative proteomics to interrogate the protein interactome, the phosphoproteome, and the interactome of BCR-FGFR1. The effects on BCR-FGFR1-stimulated cell proliferation were examined using the PLCγ1 inhibitor U73122, and the irreversible FGFR inhibitor futibatinib (TAS-120), both of which demonstrated efficacy. An absolute requirement is demonstrated for the dual binding partners Grb2 and PLCγ1 in BCR-FGFR1-driven cell proliferation, and new proteins such as ECSIT, USP15, GPR89, GAB1, and PTPN11 are identified as key effectors for hematopoietic transformation by BCR-FGFR1., Competing Interests: CONFLICTS OF INTEREST Authors have no conflicts of interest to declare., (Copyright: © 2022 Peiris et al.)

Background: The metacestode larval stage of the fox-tapeworm Echinococcus multilocularis causes alveolar echinococcosis by tumour-like growth within the liver of the intermediate host. Metacestode growth and development is stimulated by host-derived cytokines such as insulin, fibroblast growth factor, and epidermal growth factor via activation of cognate receptor tyrosine kinases expressed by the parasite. Little is known, however, concerning signal transmission to the parasite nucleus and cross-reaction with other parasite signalling systems., Methodology/principal Findings: Using bioinformatic approaches, cloning, and yeast two-hybrid analyses we identified a novel mitogen-activated kinase (MAPK) cascade module that consists of E. multilocularis orthologs of the tyrosine kinase receptor interactor Growth factor receptor-bound 2, EmGrb2, the MAPK kinase kinase EmMEKK1, a novel MAPK kinase, EmMKK3, and a close homolog to c-Jun N-terminal kinase (JNK), EmMPK3. Whole mount in situ hybridization analyses indicated that EmMEKK1 and EmMPK3 are both expressed in E. multilocularis germinative (stem) cells but also in differentiated or differentiating cells. Treatment with the known JNK inhibitor SP600125 led to a significantly reduced formation of metacestode vesicles from stem cells and to a specific reduction of proliferating stem cells in mature metacestode vesicles., Conclusions/significance: We provide evidence for the expression of a MEKK1-JNK MAPK cascade module which, in mammals, is crucially involved in stress responses, cytoskeletal rearrangements, and apoptosis, in E. multilocularis stem cells. Inhibitor studies indicate an important role of JNK signalling in E. multilocularis stem cell survival and/or maintenance. Our data are relevant for molecular and cellular studies into crosstalk signalling mechanisms that govern Echinococcus stem cell function and introduce the JNK signalling cascade as a possible target of chemotherapeutics against echinococcosis., Competing Interests: The authors have declared that no competing interests exist.

p52SHC (SHC) and GRB2 are adaptor proteins involved in the RAS/MAPK (ERK) pathway mediating signals from cell-surface receptors to various cytoplasmic proteins. To further examine their roles in signal transduction, we studied the translocation of fluorescently labeled SHC and GRB2 to the cell surface, caused by the activation of ERBB receptors by heregulin (HRG). We simultaneously evaluated activated ERK translocation to the nucleus. Unexpectedly, the translocation dynamics of SHC were sustained when those of GRB2 were transient. The sustained localization of SHC positively correlated with the sustained nuclear localization of ERK, which became more transient after SHC knockdown. SHC-mediated PI3K activation was required to maintain the sustainability of the ERK translocation regulating MEK but not RAF. In cells overexpressing ERBB1, SHC translocation became transient, and the HRG-induced cell fate shifted from a differentiation to a proliferation bias. Our results indicate that SHC and GRB2 functions are not redundant but that SHC plays the critical role in the temporal regulation of ERK activation.

5-Methylcytosine (m 5 C) is a posttranscriptional RNA modification participating in many critical bioprocesses, but its functions in human cancer remain unclear. Here, by detecting the transcriptome-wide m 5 C profiling in esophageal squamous cell carcinoma (ESCC), we showed increased m 5 C methylation in ESCC tumors due to the overexpressed m 5 C methyltransferase NSUN2. Aberrant expression of NSUN2 was positively regulated by E2F Transcription Factor 1 (E2F1). High NSUN2 levels predicted poor survival of ESCC patients. Moreover, silencing NSUN2 suppressed ESCC tumorigenesis and progression in Nsun2 knockout mouse models. Mechanistically, NSUN2 induced m 5 C modification of growth factor receptor-bound protein 2 (GRB2) and stabilized its mRNA, which was mediated by a novel m 5 C mediator, protein lin-28 homolog B (LIN28B). Elevated GRB2 levels increased the activation of PI3K/AKT and ERK/MAPK signalling. These results demonstrate that NSUN2 enhances the initiation and progression of ESCC via m 5 C-LIN28B dependent stabilization of GRB2 transcript, providing a promising epitranscriptomic-targeted therapeutic strategy for ESCC., (© 2021. The Author(s).)

Growth factor receptor-bound protein 2 (GRB2) is a trivalent adaptor protein and a key element in signal transduction. It interacts via its flanking nSH3 and cSH3 domains with the proline-rich domain (PRD) of the RAS activator SOS1 and via its central SH2 domain with phosphorylated tyrosine residues of receptor tyrosine kinases (RTKs; e.g. HER2). The elucidation of structural organization and mechanistic insights into GRB2 interactions, however, remain challenging due to their inherent flexibility. This study represents an important advance in our mechanistic understanding of how GRB2 links RTKs to SOS1. Accordingly, it can be proposed that (1) HER2 pYP-bound SH2 potentiates GRB2 SH3 domain interactions with SOS1 (an allosteric mechanism); (2) the SH2 domain blocks cSH3, enabling nSH3 to bind SOS1 first before cSH3 follows (an avidity-based mechanism); and (3) the allosteric behavior of cSH3 to other domains appears to be unidirectional, although there is an allosteric effect between the SH2 and SH3 domains., (© 2021 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.)

Ligand binding triggers clathrin-mediated and, at high ligand concentrations, clathrin-independent endocytosis of EGFR. Clathrin-mediated endocytosis (CME) of EGFR is also induced by stimuli activating p38 MAPK. Mechanisms of both ligand- and p38-induced endocytosis are not fully understood, and how these pathways intermingle when concurrently activated remains unknown. Here we dissect the mechanisms of p38-induced endocytosis using a pH-sensitive model of endogenous EGFR, which is extracellularly tagged with a fluorogen-activating protein, and propose a unifying model of the crosstalk between multiple EGFR endocytosis pathways. We found that a new locus of p38-dependent phosphorylation in EGFR is essential for the receptor dileucine motif interaction with the σ2 subunit of clathrin adaptor AP2 and concomitant receptor internalization. p38-dependent endocytosis of EGFR induced by cytokines was additive to CME induced by picomolar EGF concentrations but constrained to internalizing ligand-free EGFRs due to Grb2 recruitment by ligand-activated EGFRs. Nanomolar EGF concentrations rerouted EGFR from CME to clathrin-independent endocytosis, primarily by diminishing p38-dependent endocytosis., (© 2021 Perez Verdaguer et al.)

Ethnicity is considered to be one of the major risk factors in certain subtypes of breast cancer. However, the mechanism of this racial disparity remains poorly understood. Here, we demonstrate that SOS1, a key regulator of Ras pathway, is highly expressed in African-American (AA) patients with breast cancer compared with Caucasian-American patients. Because of the higher obesity rate in AA women, increased levels of SOS1 facilitated signal transduction of the c-Met pathway, which was highly activated in AA patients with breast cancer via hepatocyte growth factor secreted from adipocytes. Elevated expression of SOS1 also enhanced cancer stemness through upregulation of PTTG1 and promoted M2 polarization of macrophages by CCL2 in metastatic sites. SOS1 was epigenetically regulated by a super-enhancer identified by H3K27ac in AA patients. Knockout of the super-enhancer by CRISPR in AA cell lines significantly reduced SOS1 expression. Furthermore, SOS1 was posttranscriptionally regulated by miR-483 whose expression is reduced in AA patients through histone trimethylation (H3K27me3) on its promoter. The natural compound, taxifolin, suppressed signaling transduction of SOS1 by blocking the interaction between SOS1 and Grb2, suggesting a potential utility of this compound as a therapeutic agent for AA patients with breast cancer. SIGNIFICANCE: These findings elucidate the signaling network of SOS1-mediated metastasis in African-American patients, from the epigenetic upregulation of SOS1 to the identification of taxifolin as a potential therapeutic strategy against SOS1-driven tumor progression., (©2021 American Association for Cancer Research.)

Receptor tyrosine kinase (RTK)-mediated activation of downstream effector pathways such as the RAS GTPase/MAP kinase (MAPK) signaling cascade is thought to occur exclusively from lipid membrane compartments in mammalian cells. Here, we uncover a membraneless, protein granule-based subcellular structure that can organize RTK/RAS/MAPK signaling in cancer. Chimeric (fusion) oncoproteins involving certain RTKs including ALK and RET undergo de novo higher-order assembly into membraneless cytoplasmic protein granules that actively signal. These pathogenic biomolecular condensates locally concentrate the RAS activating complex GRB2/SOS1 and activate RAS in a lipid membrane-independent manner. RTK protein granule formation is critical for oncogenic RAS/MAPK signaling output in these cells. We identify a set of protein granule components and establish structural rules that define the formation of membraneless protein granules by RTK oncoproteins. Our findings reveal membraneless, higher-order cytoplasmic protein assembly as a distinct subcellular platform for organizing oncogenic RTK and RAS signaling., Competing Interests: Declarations of interest T.G.B. is an advisor to Array Biopharma/Pfizer, Revolution Medicines, Relay Therapeutics, Rain Therapeutics, Novartis, AstraZeneca, Takeda, Springworks, and Jazz Pharmaceuticals and receives research funding from Novartis, Revolution Medicines, and Strategia., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)

Vegfc/Vegfr3 signaling is critical for lymphangiogenesis, the sprouting of lymphatic vessels. In zebrafish, cells sprouting from the posterior cardinal vein can either form lymphatic precursor cells or contribute to intersegmental vein formation. Both, the Vegfc-dependent differential induction of Prox1a in sprouting cells as well as a Notch-mediated pre-pattern within intersegmental vessels have been associated with the regulation of secondary sprout behavior. However, how exactly a differential lymphatic versus venous sprout cell behavior is achieved is not fully understood. Here, we characterize a zebrafish mutant in the adaptor protein Grb2b, and demonstrate through genetic interaction studies that Grb2b acts within the Vegfr3 pathway. Mutant embryos exhibit phenotypes that are consistent with reduced Vegfr3 signaling outputs prior to the sprouting of endothelial cells from the vein. During secondary sprouting stages, loss of grb2b leads to defective cell behaviors resulting in a loss of parachordal lymphangioblasts, while only partially affecting the number of intersegmental veins. A second GRB2 zebrafish ortholog, grb2a, contributes to the development of lymphatic structures in the meninges and in the head, but not in the trunk. Our results illustrate an essential role of Grb2b in vivo for cell migration to the horizontal myoseptum and for the correct formation of the lymphatic vasculature, while being less critically required in intersegmental vein formation. Thus, there appear to be higher requirements for Grb2b and therefore Vegfr3 downstream signaling levels in lymphatic versus vein precursor-generating sprouts.

The regulation of phosphatase activity is fundamental to the control of intracellular signalling and in particular the tyrosine kinase-mediated mitogen-activated protein kinase (MAPK) pathway. Shp2 is a ubiquitously expressed protein tyrosine phosphatase and its kinase-induced hyperactivity is associated with many cancer types. In non-stimulated cells we find that binding of the adaptor protein Grb2, in its monomeric state, initiates Shp2 activity independent of phosphatase phosphorylation. Grb2 forms a bidentate interaction with both the N-terminal SH2 and the catalytic domains of Shp2, releasing the phosphatase from its auto-inhibited conformation. Grb2 typically exists as a dimer in the cytoplasm. However, its monomeric state prevails under basal conditions when it is expressed at low concentration, or when it is constitutively phosphorylated on a specific tyrosine residue (Y160). Thus, Grb2 can activate Shp2 and downstream signal transduction, in the absence of extracellular growth factor stimulation or kinase-activating mutations, in response to defined cellular conditions. Therefore, direct binding of Grb2 activates Shp2 phosphatase in the absence of receptor tyrosine kinase up-regulation.

A subset of prostate cancer displays a poor clinical outcome. Therefore, identifying this poor prognostic subset within clinically aggressive groups (defined as a Gleason score (GS) ≧8) and developing effective treatments are essential if we are to improve prostate cancer survival. Here, we performed a bioinformatics analysis of a TCGA dataset (GS ≧8) to identify pathways upregulated in a prostate cancer cohort with short survival. When conducting bioinformatics analyses, the definition of factors such as "overexpression" and "shorter survival" is vital, as poor definition may lead to mis-estimations. To eliminate this possibility, we defined an expression cutoff value using an algorithm calculated by a Cox regression model, and the hazard ratio for each gene was set so as to identify genes whose expression levels were associated with shorter survival. Next, genes associated with shorter survival were entered into pathway analysis to identify pathways that were altered in a shorter survival cohort. We identified pathways involving upregulation of GRB2. Overexpression of GRB2 was linked to shorter survival in the TCGA dataset, a finding validated by histological examination of biopsy samples taken from the patients for diagnostic purposes. Thus, GRB2 is a novel biomarker that predicts shorter survival of patients with aggressive prostate cancer (GS ≧8).

Pulmonary arterial hypertension (PAH) is a progressive and lethal cardiopulmonary. Pulmonary vascular remodeling (PVR) caused by excessive proliferation and apoptosis resistance of pulmonary artery smooth muscle cells (PASMCs) is the chief pathological feature of PAH. Dioscin is a natural product that possesses multiple pharmacological activities, but its effect on PAH remains unclear. In this study, effect of dioscin on vascular remodeling in PAH was assessed in hypoxia-induced PASMCs, hypoxia-induced and monocrotaline (MCT)-induced rats. Western blot, Real-time PCR and siRNA transfection tests were applied to evaluate the possible mechanisms of dioscin. In vitro experiments, results showed dioscin markedly inhibited the proliferation and migration, and promoted apoptosis of hypoxic PASMCs. In vivo, dioscin significantly decreased the right ventricular systolic pressure (RVSP) and right ventricular hypertrophy index (RVHI), and improved pulmonary vascular stenosis in rats induced by hypoxia or MCT. Molecular mechanism studies showed that dioscin significantly reduced the expression of growth factor receptor-bound protein 2 (GRB2). Subsequently, dioscin reduced the expressions of Ras, Cyclin D1, CDK4, c-Fos, PCNA and p-ERK to inhibit proliferation and migration of PASMCs, inhibited p-PI3K and p-AKT levels and increased Bax/Bcl2 ratio to promote cell apoptosis. GRB2 siRNA transfection in PASMCs further confirmed that the inhibitory action of dioscin in PAH was evoked by adjusting GRB2/ERK/PI3K-AKT signal. Taken together, our study indicated that dioscin attenuates PAH through adjusting GRB2/ERK/PI3K-AKT signal to inhibit PASMCs proliferation and migration, and promote apoptosis, and dioscin may be developed as a therapeutic strategy for treating PAH in the future., (Copyright © 2020 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Neonatal herpes simplex virus (HSV) infection is a devastating disease with high mortality, particularly when disseminated. Studies in adults and children suggest that susceptibility to herpes simplex encephalitis (HSE) may represent phenotypes for inborn errors in toll-like receptor 3 (TLR3) signaling. However, the genetic basis of susceptibility to neonatal HSV including disseminated disease remains unknown. To test the hypothesis that variants in known HSE-susceptible genes as well as genes mediating HSV immunity will be identified in neonatal HSV, we performed an unbiased exome sequencing study in 10 newborns with disseminated, HSE, and skin, eyes, and mouth disease. Determination of potential impact on function was determined by following American College of Medical Genetics and Genomics guidelines. We identified deleterious and potentially deleterious, rare variants in known HSE-related genes including a stop IRF3 variant (disseminated), nonsynonymous variants in TLR3 and TRAF3 (HSE), STAT1 (skin, eyes, and mouth), and DBR1 (disseminated) in our cohort. Novel and rare variants in other immunodeficiency genes or HSV-related immune genes GRB2 , RAG2 , PRF1 , C6 , C7 , and MSR1 were found in 4 infants. The variant in GRB2 , essential for T-lymphocyte cell responses to HSV, is a novel stop variant not found in public databases. In this pilot study, we identified deleterious or potentially deleterious variants in TLR3 pathway and genes that regulate anti-HSV immunity in neonates with HSV including disseminated disease. Larger, definitive studies incorporating functional analysis of genetic variants are required to validate these data and determine the role of immune genetic variants in neonatal HSV susceptibility., Competing Interests: POTENTIAL CONFLICT OF INTEREST: The authors have indicated they have no potential conflicts of interest to disclose., (Copyright © 2021 by the American Academy of Pediatrics.)

Genistein is a type of isoflavone, which has been widely described as an antitumor agent in many cancers. The present study aimed to provide information on the mechanisms of genistein's activity and thus enable a wider range of targeted therapies in hepatitis B virus (HBV)-related liver cancer. We searched the DrugBank database for direct targets of genistein, which were then analyzed through the STRING (Search Tool for the Retrieval of Interacting Genes/Proteins) database to predict their secondary protein targets. Thirteen primary protein targets of genistein and 209 secondary protein targets-associated genes were identified. The data were integrated into the network of protein targets-associated genes and visualized with the Cytoscape software. We further carried out GO (Gene Ontology) analysis and KEGG (Kyoto Encyclopedia of Gene and Genome) pathway analysis using DAVID (database for annotation, visualization, and integrated discovery) tool. The top 14 KEGG pathways were further assessed, and 19 overlapping genes derived from pathways of hepatitis B and cancer were discovered. The overlapping targets were further mapped in the online tool UALCAN to evaluate the survival rate of hepatocellular carcinoma (HCC) patients. We found that the overexpression of Grb2 (growth factor receptor-binding protein 2) ( p < 0.0001) was linked to poor overall survival for liver HCC patients, followed by AKT1 ( p  = 0.0015) and PIK3CA ( p  = 0.0088). The present study analyzes the drug-target-disease network and may prove to be a useful tool in gene-phenotype connectivity for genistein in HBV-related liver cancer. Our data also pave the way for further research on Grb2 during the development of chronic HBV infection in liver cancer.

Autophagy has been shown to maintain neural system homeostasis during stroke. However, the molecular mechanisms underlying neuronal autophagy in ischemic stroke remain poorly understood. This study aims to investigate the regulatory mechanisms of the pathway consisting of MEG3 (maternally expressed gene 3), microRNA-378 (miR-378), and GRB2 (growth factor receptor-bound protein 2) in neuronal autophagy and neurological functional impairment in ischemic stroke. A mouse model of the middle cerebral artery occluded-induced ischemic stroke and an in vitro model of oxygen-glucose deprivation-induced neuronal injury were developed. To understand the role of the MEG3/miR-378/GRB2 axis in the neuronal regulation, the expression of proteins associated with autophagy in neurons was measured by Western blotting analysis, and neuron death was evaluated using a lactate dehydrogenase leakage rate test. First, it was found that the GRB2 gene, up-regulated in middle cerebral artery occluded-operated mice and oxygen-glucose deprivation-exposed neurons, was a target gene of miR-378. Next, miR-378 inhibited neuronal loss and neurological functional impairment in mice, as well as neuronal autophagy and neuronal death by silencing of GRB2. Confirmatory in vitro experiments showed that MEG3 could specifically bind to miR-378 and subsequently up-regulate the expression of GRB2, which in turn suppressed the activation of Akt/mTOR pathway. Taken together, these findings suggested that miR-378 might protect against neuronal autophagy and neurological functional impairment and proposed that a MEG3/miR-378/GRB2 regulatory axis contributed to better understanding of the pathophysiology of ischemic stroke., Competing Interests: Conflict of interest—The authors declare that they have no conflicts of interest with the contents of this article., (© 2020 Luo et al.)

Understanding the functions of genes related to disease resistance and identifying polymorphisms in these genes are essential in molecular breeding for disease resistance. Viral nervous necrosis (VNN) is one of the major diseases in the Asian seabass, Lates calcarifer. Our previous works on QTL mapping, GWAS and cell-line transcriptome analysis of the Asian seabass after NNV challenge revealed that the gene GAB3 might be a candidate gene for VNN resistance. In this study, we cloned and characterized GAB3, and identified SNPs in the gene of the Asian seabass. The cDNA of the gene was 2165 bp, containing an ORF of 1674 bp encoding 557 amino acids. The gene consisted of 10 exons and nine introns. It was ubiquitously expressed in normal fish. An analysis of the association between two SNPs in the second intron and NNV resistance in 1035 fish descended from 43 families revealed that the two SNPs were significantly associated with VNN resistance. After NNV infection, the expression of GAB3 was significantly increased in the brain, spleen, muscle and gut, and was suppressed in the liver. The GAB3 protein was localized in the nucleus. Overexpression of GAB3 with specific GAB3-pcDNA was positively correlated to increased viral RNA and titer in NNV-infected Asian seabass cells. Our study provides new evidence to support that GAB3 may be an important gene related to NNV resistance. In addition, the SNPs provide DNA markers for the selection of candidate genes resistance to NNV at the juvenile stage of Asian seabass., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) were first-line treatments for NSCLC patients with EGFR-mutations. However, about 30 % of responders relapsed within six months because of acquired resistance. In this study, we used Connectivity Map (CMap) to discover a drug capable of reversing acquired EGFR-TKIs resistance. To investigate Lymecycline's ability to reverse acquired EGFR-TKIs resistance, two Icotinib resistant cell lines were constructed. Lymecycline's ability to suppress the proliferation of Icotinib resistant cells in vitro and in vivo was then evaluated. Molecular targets were predicted using network pharmacology and used to identify the molecular mechanism. Growth factor receptor-bound protein 2 (GRB2) is an EGFR-binding adaptor protein essential for EGFR phosphorylation and regulation of AKT/ERK/STAT3 signaling pathways. Lymecycline targeted GRB2 and inhibited the resistance of the cell cycle to EGFR-TKI, arresting disease progression and inducing apoptosis in cancer cells. Combined Lymecycline and Icotinib treatment produced a synergistic effect and induced apoptosis in HCC827R5 and PC9R10 cells. Cell proliferation in resistant cancer cells was significantly inhibited by the combined Lymecycline and Icotinib treatment in mouse models. Lymecycline inhibited the resistance of the cell cycle to EGFR-TKI and induced apoptosis in NSCLC by inhibiting EGFR phosphorylation and GRB2-mediated AKT/ERK/STAT3 signaling pathways. This provided strong support that Lymecycline when combined with EGFR targeting drugs, enhanced the efficacy of treatments for drug-resistant NSCLC., (Copyright © 2020 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

The dysfunction of bone marrow mesenchymal stem cells (BMSCs) in osteogenic differentiation is one of the main causes of age-related bone loss. Our previous studies have shown that low-magnitude vibration (LMV) induces the osteogenic differentiation of BMSCs derived from ovariectomized osteoporotic rats. To investigate whether LMV promotes osteogenic differentiation of BMSCs and its underlying mechanisms in aged rats, 20-month-old female Sprague-Dawley rats (n = 20) were randomly divided into LMV group (rats were vibrated at 0.3 g and 90 Hz for 30 minutes, once daily, 5 days a week until 12 weeks for subsequent analysis, n = 10), static group (rats were placed in the box on the vibration platform without vibration, n = 10); 6-month-old female Sprague-Dawley rats were used as control (young group, n = 10). The bone mineral density and bone strength of aged rats were significantly decreased compared with the young rats. Furthermore, the primary BMSCs isolated and cultured from the aged rats with the whole-bone marrow differential pasting method showed a decreased ability in osteogenic differentiation compared with that from the young rats. Then the differentially expressed miRNAs between the aged and young rat-derived BMSCs were screened by high-throughput sequencing and verified by qRT-PCR, and we found that miR-378a-3p was significantly downregulated in the aged rat-derived BMSCs compared with the young rat-derived BMSCs. By transfecting miRNA mimics and inhibitors, miR-378a-3p was confirmed to promote the expression levels of osteogenic genes (Runx2, ALP, Col I, and OCN) and ALP activity of the aged rat-derived BMSCs. Meanwhile, the expression levels of osteogenic genes and miR-378a-3p of aged rat-derived BMSCs were significantly upregulated by LMV (cells were vibrated at 0.3 g and 90 Hz for 30 minutes a day, until 5 days for subsequent analysis), while the LMV-induced osteogenic gene expression levels of aged rat-derived BMSCs were suppressed by miR-378a-3p inhibitors. Furthermore, the inhibition of growth factor receptor-bound protein 2 (Grb2) by miR-378a-3p and Grb2-siRNA promoted the LMV-induced osteogenic differentiation of aged rat-derived BMSCs. Additionally, LMV was found to promote bone mineral density and bone strength of aged rats in vivo, as well as upregulating the expression level of miR-378a-3p and downregulating the expression level of Grb2 of BMSCs from aged rats. These results suggest that LMV induces osteogenic differentiation of BMSCs through miR-378a-3p/Grb2 pathway to improve bone mineral density and mechanical properties in a rat model of age-related bone loss., (© 2020 Federation of American Societies for Experimental Biology.)

In this study, we investigated the mechanistic role of the long non-coding RNA (lncRNA) AC092171.4 in hepatocellular carcinoma (HCC). AC092171.4 was significantly upregulated in HCC tumor tissues compared to normal liver tissues. HCC patients with high AC092171.4 expression showed poorer overall survival (OS) and disease-free survival (DFS) than those with low AC092171.4 expression. In vitro cell proliferation, migration and invasiveness were all higher in AC092171.4-overexpressing HCC cells, but lower in AC092171.4-silenced HCC cells, than in controls. Balb/c nude mice injected with AC092171.4-silenced HCC cells had smaller xenograft tumors, which showed less growth and pulmonary metastasis than control tumors. Bioinformatics analyses and dual luciferase reporter assays confirmed that AC092171.4 binds directly to miR-1271, which targets the 3'UTR of GRB2 mRNA. AC092171.4 expression correlates negatively with miR1271 expression and correlates positively with GRB2 mRNA expression in HCC tissues from patients. HCC cells co-transfected with miR-1271 mimics and sh-AC092171.4 show less proliferation, migration, invasiveness, GRB2 protein, and epithelial to mesencyhmal transition (EMT) than sh-AC092171.4-transfected HCC cells. These findings demonstrate that AC092171.4 promotes growth and progression of HCC by sponging miR-1271 and upregulating GRB2. This makes AC092171.4 a potential prognostic indicator and therapeutic target for HCC patients.

Long noncoding RNA SBF2 antisense RNA 1 (lncRNA SBF2-AS1) has been reported to be involved in non-small-cell lung cancer (NSCLC) tumorigenesis. However, the biological role and regulatory mechanism of lncRNA SBF2-AS1 on NSCLC metastasis remain largely unknown. In this study, the expression level and functional role of SBF2-AS1 were investigated in both NSCLC tissues and cell lines. We found that SBF2-AS1 was upregulated in both NSCLC tissues and cell lines. Patients with high levels of SBF2-AS1 have larger tumors, higher malignancy, and poor prognosis. Knockdown of SBF2-AS1 significantly inhibited tumor growth in vivo and cell proliferation, migration, and invasion in vitro . Moreover, bioinformatics analysis, chromatin immunoprecipitation assay, and luciferase reporter assay proved that the upregulation of SBF2-AS1 was mediated by transcription factor E2F1. Further experiments demonstrated that miR-362-3p had complementary binding site with 3'-UTR of SBF2-AS1. Besides, luciferase reporter assay validated that GRB2 was the target protein of miR-362-3p. Rescue experiments showed that SBF2-AS1 silencing inhibited cell invasion and migration, while cotransfection si-SBF2-AS1 and miR-362-3p inhibitor rescued the effect of si-SBF2-AS1. These results demonstrate that E2F1-induced overexpression of SBF2-AS1 promotes the expression of GRB2 by targeting miR-362-3p to facilitate the metastasis of NSCLC.

Renal ischemia-reperfusion (RI/R) injury with high morbidity and mortality is one common clinical disease. Development of drug targets to treat the disorder is critical important. MiR-27a-3p plays important roles in regulating oxidative stress. However, its effects on RI/R injury have not been reported. In this paper, hypoxia/reoxygenation (H/R) models on NRK-52E and HK-2 cells, and RI/R model in C57BL/6 mice were established. The results showed that H/R in vitro decreased cell viability and increased ROS levels in cells, and RI/R caused renal injury and oxidative damage in mice. The expression levels of miR-27a-3p were up-regulated based on real-time PCR and FISH assays in model groups compared with control groups, which directly targeted Grb2 based on dual luciferase reporter assay and co-transfaction test. In addition, miR-27a- 3p markedly reduced Grb2 expression to down-regulate the expression levels of p-PI3K, p-AKT, Nrf2, HO-1, and up-regulate Keap1 expression in model groups. MiR-27a-3p mimics in vitro enhanced H/R-caused oxidative stress via increasing ROS levels and decreasing Grb2 expression to down-regulate PI3K-AKT signal. In contrary, miR-27a-3p inhibitor in vitro significantly reduced H/R-caused oxidative damage via decreasing ROS levels and increasing Grb2 expression to up-regulate PI3K-AKT signal. In vivo, miR-27a- 3p agomir exacerbated RI/R-caused renal damage by decreasing SOD level and increasing Cr, BUN, MDA levels via suppressing Grb2 expression to down-regulate PI3K- AKT signal. However, miR-27a -3p antagomir alleviated RI/R-caused oxidative damage via increasing Grb2 expression to up-regulate PI3k-AKT signal. Grb2siRNA in mice further enhanced RI/R-caused renal injury by increasing Cr, BUN, MDA levels and decreasing SOD level via inhibiting the expression levels of Grb2, Nrf2, HO-1, and increasing Keap1 expression. Our data showed that miR-27a-3p aggravated RI/R injury by promoting oxidative stress via targeting Grb2, which should be considered as one new drug target to treat RI/R injury., Competing Interests: Declaration of Competing Interest In this paper, the authors asserted that they had no conflict of interest., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Although cytomegalovirus (HCMV) infection is asymptomatic in healthy individuals, the virus can remain latent for many years due to its ability to evade host immune surveillance. However, reactivation of HCMV can lead to life-threatening disease. Recent studies have shown that HCMV infection mediates immune escape by regulating macrophage activity, although the role of the HCMV-encoded IE2 protein is unclear. A ul122 transgenic mouse model was created to stably expresses the IE2 protein, and the proportion of M1 and M2 macrophage populations in their spleen and bone marrow was compared to that in wild-type controls. In addition, the phagocytic function of the macrophages was evaluated in terms of neutral red dye uptake. Spleen and bone marrow macrophages in IE2-expressing mice were mainly of the M2 phenotype and displayed enhanced phagocytic function compared to that in control mice. The relative levels of expression of macrophage-related GRB2 and of IL-4, IFN-γ, IL-13, and TNF-α were also analyzed in the spleen and bone marrow of the two groups. The IE2-expressing mice had increased expression of GRB2 and increased expression of the M2-related cytokines IL-4 and IL-13. Taken together, the current results suggest that HCMV IE2 polarizes the host macrophages to the M2 type via a GRB2/IL-4-related pathway, which enables long-term survival of the virus in the host.

In this study, we identified a novel circRNA, circ&#95;0002483, and further investigated its functions in the progression and Taxol resistance of NSCLC. We found that circ&#95;0002483 was expressed at low levels in NSCLC tissues and cell lines. Functional assays indicated that circ&#95;0002483 overexpression significantly inhibited NSCLC cell proliferation and invasion in vitro and in vivo and enhanced the sensitivity of NSCLC cells to Taxol. Mechanistically, circ&#95;0002483 was identified to sponge multiple miRNAs including miR-182-5p (also named miR-182), miR-520q-3p, miR-582-3p, miR-587, and miR-655. In addition, circ&#95;0002483 was also demonstrated to regulate the expression of GRB2, FOXO1, and FOXO3, three target genes of miR-182-5p, by sponging miR-182-5p. Circ&#95;0002483 was demonstrated to inhibit NSCLC progression in vitro and in vivo and enhanced the sensitivity of NSCLC cells to Taxol by sponging miR-182-5p to release the inhibition on GRB2, FOXO1, and FOXO3 mRNAs.

Grb2-associated regulator of Erk/MAPK (GAREM), is an adaptor protein related to the several cell growth factor receptor-signaling. The GAREM family has two subtypes, GAREM1 and GAREM2, both encoded in the human and mouse genome. Recent genome-wide research identified GAREM2 as a candidate of neurodegenerative diseases. Here, we use knockout (KO) mice to show the role of GAREM2, that is highly expressed in the brain. According to the comprehensive behavioral battery, they exhibited less anxiety both in elevated plus maze and open field tests, mildly increased social approaching behavior in the reciprocal social interaction test, and longer latency to immobility in the tail suspension test as compared to wild-type (WT). Additionally, the extension of neurites in the primary cultured neurons was suppressed in ones derived from GAREM2 KO mice. Furthermore, we also identified Intersectin, as a binding partner of GAREM2 in this study. Intersectin is also a multi-domain adaptor protein that regulates endocytosis and cell signaling, which can potentially alter the subcellular localization of GAREM2. The important molecules, such as the neurotrophin receptor and Erk family, that are involved in the signaling pathway of the neural cell growth in the mouse brain, have been reported to participate in emotional behavior. As GAREM plays a role in the cellular growth factor receptor signaling pathway, GAREM2 may have a common role related to the transduction of Erk signaling in the higher brain functions.

Long noncoding RNAs (lncRNAs) are a class of novel molecular regulators in cardiac development and diseases. However, the role of specific lncRNAs in cardiac fibrosis remains to be fully explored. The aim of the present study was to investigate the effects and underlying mechanisms of lncRNA PCFL (pro-cardiac fibrotic lncRNA) on cardiac fibrosis after myocardial infarction (MI). Cardiac fibroblasts (CFs) with gain and loss of function of PCFL and mice with global knockout or overexpression of PCFL were used to explore the effects of PCFL on cardiac fibrosis. The data showed that PCFL was significantly increased in hearts of mice subjected to MI and CFs treated with transforming growth factor-β1 (TGF-β1). Overexpression of PCFL promoted collagen production and CF proliferation, while silencing PCFL exhibited the opposite effects. Compared with wild type MI mice, heterozygous knockout of PCFL (PCFL +/- ) in mice significantly improved heart function and reduced cardiac fibrosis after MI. While overexpression of PCFL impaired cardiac function and aggravated MI-induced cardiac fibrosis. The mechanistic data demonstrated that PCFL functioned as a sponge of miR-378. Luciferase reporter assay confirmed the interaction of PCFL with miR-378. MiR-378 inhibited collagen production by suppressing its target gene, GRB2 (growth factor receptor bound protein 2). Knockdown of PCFL led to an increase of miR-378. Silencing of miR-378 reserved the inhibitory effects of PCFL knockdown on collagen production, cell proliferation and GRB2 expression. In conclusion, the study identifies a novel pro-fibrotic lncRNA, PCFL, and the mechanism involves the direct interaction of PCFL with miR-378, which in turn relieves the inhibition effect of miR-378 on GRB2 and promotes cardiac fibrosis., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Growth factor receptor bound protein 2 (Grb2) is an adaptor protein critical for signal transduction and endocytosis, but its role in DNA damage response (DDR) remains unknown. Here, we report that either knockdown of Grb2 or overexpression of the mutated Grb2 promotes micronuclei formation in response to oxidative stress. Furthermore, Grb2 was demonstrated to interact with phosphatase and tensin homologue (PTEN; a tumor suppressor essential for nuclear stability), and the loss of Grb2 reduced the nuclear-localized PTEN, which was further decreased upon stimulation with hydrogen peroxide (H 2 O 2 ). Overexpression of the T398A-mutated, nuclear-localized PTEN reduced micronuclei frequency in the cells deficient of functional Grb2 via rescuing the H 2 O 2 -dependent expression of Rad51, a protein essential for the homologous recombination (HR) repair process. Moreover, depletion of Grb2 markedly decreased the expression of Rad51 and its interaction with PTEN. Notably, Rad51 showed a preference to immunoprecipation with the T398A-PTEN mutant, and silencing of Rad51 alone accumulated micronuclei concurring with decreased expression of both Grb2 and PTEN. Our findings indicate that Grb2 interacts with PTEN and Rad51 to regulate genomic stability in DDR by mediating the nuclear translocation of PTEN to affect the expression of Rad51.