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Lung cancer, the most concerning malignancy worldwide and one of the leading causes of cancer-related deaths. Growing evidence indicates that Angiomotin (Amot)-p130 plays an important role in types of cancer, including breast cancer and gastric cancer. Moreover, evidence suggested that the low Amot-p130 expression correlates with the poor prognosis of lung cancer patients, however, the role and mechanism of Amot-p130 in lung cancer is still unclear. In this study, we showed that Amot-p130 expression was reduced in lung cancer tissues, compared with the adjacent para-carcinoma tissues. In addition, we observed that the reduced expression of Amot-p130 was associated with vasculogenic mimicry (VM) channels formation in lung cancer tissues. Amot-p130 expression was differently expression in lung cancer cell line H446, H1688 and H2227 compared with the normal human lung cells HFL1. To clarify the role of Amot-p130 in lung cancer, we constructed the Amot-p130 expressing H446 cells and Amot-p130 silencing H1299 cells. We confirmed that Amot-p130 overexpression inhibited the migration and invasion of lung cancer cells, whereas its silence promoted cell migration and invasion. Interestingly, we also found that Amot-p130 overexpression suppressed VM tube formation in H446 cells, while its knockdown promoted VM tube formation in H2227 cells. Further studies suggested that Amot-p130 plays roles in M tube formation of lung cancer cell V are independent on smad2/3 signaling pathway. Finally, inoculation of Amot-p130 expressing H446 cells and Amot-p130 silencing H1299 cells into nude mice suppressed tumor growth, when compared with the control group. Based on these results, Amot-p130 serves as a possible diagnostic and therapeutic target in lung cancer patients, and may be an effective mediator of VM formation in lung cancer.

To explore the regulatory relationship between Chloride intracellular channel 1 (CLIC1) and Angiomotin (AMOT)-p130, and reveal the role of AMOT-p130 in gastric cancer (GC). Immunohistochemistry was performed to analyze the expression of CLIC1 and AMOT-p130 in GC tissues and adjacent tissues. The expression of AMOT-p130 upon CLIC1 silencing was analyzed using RT-PCR, western blot, and immunofluorescence in GC cells. Transwell and wound-healing assays were performed to detect migration and invasion in GC cells. The changes in EMT-related proteins were detected using western blot. Our study found that high CLIC1 expression was significantly associated with low AMOT-p130 expression in GC tissues. Silencing CLIC1 expression in MGC-803 cells (MGC-803 CLIC1 KO) and AGS cells (AGS CLIC1 KO) decreased the invasive and migratory abilities of tumor cells, which were induced by the upregulation of AMOT-p130. Subsequently, we demonstrated that AMOT-p130 inhibits the invasive and migratory abilities of GC cells by inhibiting epithelial–mesenchymal transition. Our study suggests that AMOT-p130 could inhibit epithelial–mesenchymal transition in GC cells. CLIC1 may participate in the metastatic progression of GC by downregulating the expression of AMOT-p130.

The Ebola virus (EBOV) VP40 matrix protein (eVP40) orchestrates assembly and budding of virions in part by hijacking select WW-domain–bearing host proteins via its PPxY late (L)-domain motif. Angiomotin (Amot) is a multifunctional PPxY-containing adaptor protein that regulates angiogenesis, actin dynamics, and cell migration/motility. Amot also regulates the Hippo signaling pathway via interactions with the WW-domain–containing Hippo effector protein Yes-associated protein (YAP). In this report, we demonstrate that endogenous Amot is crucial for positively regulating egress of eVP40 virus-like particles (VLPs) and for egress and spread of authentic EBOV. Mechanistically, we show that ectopic YAP expression inhibits eVP40 VLP egress and that Amot co-expression rescues budding of eVP40 VLPs in a dose-dependent and PPxY-dependent manner. Moreover, results obtained with confocal and total internal reflection fluorescence microscopy suggested that Amot's role in actin organization and dynamics also contributes to promoting eVP40-mediated egress. In summary, these findings reveal a functional and competitive interplay between virus and host proteins involving the multifunctional PPxY-containing adaptor Amot, which regulates both the Hippo pathway and actin dynamics. We propose that our results have wide-ranging implications for understanding the biology and pathology of EBOV infections.

Hippo signaling functions to limit cellular growth, but the aberrant nuclear accumulation of its downstream YAP1 leads to carcinogenesis. YAP1/TEAD complex activates the oncogenic downstream transcription, such as CTGF and c-Myc. How YAP1 is protected in the cytoplasm from ubiquitin-mediated degradation remains elusive. In this study, a member of Angiomotin (Motin) family, AMOTL1 (Angiomotin Like 1), was screened out as the only one to promote YAP1 nuclear accumulation by several clinical cohorts, which was further confirmed by the cellular functional assays. The interaction between YAP1 and AMOTL1 was suggested by co-immunoprecipitation and immunofluorescent staining. The clinical significance of the AMOTL1–YAP1–CTGF axis in gastric cancer (GC) was analyzed by multiple clinical cohorts. Moreover, the therapeutic effect of targeting the oncogenic axis was appraised by drug-sensitivity tests and xenograft-formation assays. The upregulation of AMOTL1 is associated with unfavorable clinical outcomes of GC, and knocking down AMOTL1 impairs its oncogenic properties. The cytoplasmic interaction between AMOTL1 and YAP1 protects each other from ubiquitin-mediated degradation. AMOTL1 promotes YAP1 translocation into the nuclei to activate the downstream expression, such as CTGF. Knocking down AMOTL1, YAP1, and CTGF enhances the therapeutic efficacies of the first-line anticancer drugs. Taken together, AMOTL1 plays an oncogenic role in gastric carcinogenesis through interacting with YAP1 and promoting its nuclear accumulation. A combination of AMOTL1, YAP1, and CTGF expression might serve as a surrogate of Hippo activation status. The co-activation of the AMOTL1/YAP1–CTGF axis is associated with poor clinical outcomes of GC patients, and targeting this oncogenic axis may enhance the chemotherapeutic effects.

Mechanical cues regulate the function of a broad range of stem cells in culture and in tissue. For example, soft substrates promote the neuronal differentiation of neural stem cells (NSCs) by suppressing cytoskeletal contractility. However, the mechanisms that link cytoskeletal signaling to the transcriptional regulatory processes that ultimately govern stiffness-dependent NSC fate commitment are not fully understood. Here, we show that Angiomotin (AMOT), which can bind both F-actin and the neurosuppressive transcriptional coactivator Yes-associated protein (YAP), is critical for mechanotransduction in NSCs. On soft substrates, loss of AMOT substantially reduces neurogenesis, whereas on stiff substrates, loss of AMOT negates the rescue of neurogenesis normally induced by pharmacologic inhibition of myosin activity. Furthermore, overexpression of a phospho-mimetic S175E AMOT mutant, which has been established to enhance AMOT-YAP binding, increases β-catenin activity and rescues neurogenesis on stiff substrates. Together, our data identify AMOT as an important intermediate signal transducer that allows NSCs to sense and respond to extracellular stiffness cues.

Chemoresistance of triple negative breast cancer against paclitaxel (PAX) is one of the major issues for the patients under chemotherapy. However, the mechanism by which the breast cancer cells are resistant to PAX remains unclear. Here, we identified a circular RNA of angiomotin-like 1 (circAMOTL1) as an important player which may be responsible for the adverse resistance against PAX in breast cancer cells. The circAMOTL1 were overexpressed in MDA-MB-231 breast cancer cells via transfection of circAMOTL1 construct. Overexpression of circAMOTL1 caused significant increase of cell viability, reduction of apoptosis, and enhancement of invasion when MDA-MB-231 cells were exposed to PAX compared to those cells with vector control. Moreover, these resistant effects could be blocked by the application of circAMOTL1 siRNA. In these circAMOTL1 overexpressing cells, we found notable increase of both phosphorylated and total AKT protein, which suggested that AKT might be the downstream factor mediating the resistant effects. Consequently, the gene and protein expression of AKT related pro-apoptotic (BAX and BAK) and anti-apoptotic (BCL-2) factors were significantly changed by circAMOTL1 as well. These results suggest circAMOTL1 may play an important role in the PAX resistance of breast cancer cells via regulation of AKT pathway, facilitation of anti-apoptotic protein and inhibition of pro-apoptotic protein. While providing a new mechanism of PAX resistance in breast cancer cells, our findings may lay groundwork for a novel therapeutic target of the breast cancer treatment in the future.

Ebola (EBOV) and Marburg (MARV) viruses continue to emerge and cause severe hemorrhagic disease in humans. A comprehensive understanding of the filovirus-host interplay will be crucial for identifying and developing antiviral strategies. The filoviral VP40 matrix protein drives virion assembly and egress, in part by recruiting specific WW-domain-containing host interactors via its conserved PPxY Late (L) domain motif to positively regulate virus egress and spread. In contrast to these positive regulators of virus budding, a growing list of WW-domain-containing interactors that negatively regulate virus egress and spread have been identified, including BAG3, YAP/TAZ and WWOX. In addition to host WW-domain regulators of virus budding, host PPxY-containing proteins also contribute to regulating this late stage of filovirus replication. For example, angiomotin (AMOT) is a multi-PPxY-containing host protein that functionally interacts with many of the same WW-domain-containing proteins that regulate virus egress and spread. In this report, we demonstrate that host WWOX, which negatively regulates egress of VP40 VLPs and recombinant VSV-M40 virus, interacts with and suppresses the expression of AMOT. We found that WWOX disrupts AMOT’s scaffold-like tubular distribution and reduces AMOT localization at the plasma membrane via lysosomal degradation. In sum, our findings reveal an indirect and novel mechanism by which modular PPxY/WW-domain interactions between AMOT and WWOX regulate PPxY-mediated egress of filovirus VP40 VLPs. A better understanding of this modular network and competitive nature of protein-protein interactions will help to identify new antiviral targets and therapeutic strategies.IMPORTANCEFiloviruses (Ebola [EBOV] and Marburg [MARV]) are zoonotic, emerging pathogens that cause outbreaks of severe hemorrhagic fever in humans. A fundamental understanding of the virus-host interface is critical for understanding the biology of these viruses and for developing future strategies for therapeutic intervention. Here, we reveal a novel mechanism by which host proteins WWOX and AMOTp130 interact with each other and with the EBOV matrix protein VP40 to regulate VP40-mediated egress of virus like particles (VLPs). Our results highlight the biological impact of competitive interplay of modular virus-host interactions on both the virus lifecycle and the host cell.

The kinesin-3 motor KIF13B functions in endocytosis, vesicle transport, and regulation of ciliary length and signaling. Direct binding of the membrane-associated guanylate kinase (MAGUK) DLG1 to KIF13B’s MAGUK-binding stalk (MBS) domain relieves motor autoinhibition and promotes microtubule plus end-directed cargo transport. Here we characterize Angiomotin isoform 2 (Ap80) as a novel KIF13B interactor that promotes binding of another MAGUK, the polarity protein and Crumbs complex component PALS1, to KIF13B. Live cell imaging analysis indicated that Ap80 is concentrated at the base of primary cilia and recruits PALS1 to this site, but is not itself a cargo of KIF13B. Consistent with a ciliary function for Ap80, its depletion led to elongated primary cilia while its overexpression caused ciliary shortening. Our results suggest that Ap80 may specifically activate KIF13B cargo binding at the base of primary cilia to regulate ciliary length.

Yes-associated protein (YAP) regulates numerous cellular homeostasis processes and malignant transformation. We found that YAP influences ZO-1-mediated cell migration using E-cadherin-restored EC96 cells derived from gastric malignant AGS cells. Ectopic expression of E-cadherin enhanced straightforward migration of cells, in comparison to the meandering movement of parental AGS cells. In EC96 cells, YAP and ZO-1 expression increased but nuclear YAP levels and activity were reduced. Nuclear factor-κB (NF-κB) mediated the increase in ZO-1 expression, possibly stabilizing cytoplasmic YAP post-translationally. Downregulation of YAP expression using siYAP RNA or stable knock-down inhibited straightforward cell migration by fragmenting ZO-1 containing tight junctions (TJs) but not adherens junctions, implying involvement of YAP in ZO-1-mediated cell migration. The association of YAP with ZO-1 was mediated by angiomotin (AMOT) because downregulation of AMOT dissociated YAP from ZO-1 and reduced cell migration. E-cadherin restoration in malignant cancer cells induced NF-κB signaling to enhance ZO-1 expression and subsequently stabilize YAP. At high expression levels, YAP associates with ZO-1 via AMOT at TJs, influencing ZO-1-mediated cell migration and maintaining TJ integrity.

Angiomotin-like 1 (AMOTL1) is reportedly a pivotal tumor-associated protein that is strongly associated with the tumorigenesis of multiple malignant tumors. However, the issue of whether AMOTL1 plays a role in the tumorigenesis of glioma remains unclear. The aim of this work was to explore the possible relationship between AMOTL1 and glioma progression. Results demonstrated that high levels of AMOTL1 in glioma tissues were associated with a reduced survival rate in patients with glioma. Cellular functional assays revealed that silencing of AMOTL1 in glioma cell lines substantially decreased cell proliferation and invasion and increased cell apoptosis. Further investigation revealed that silencing of AMOTL1 inhibited the activation of yes-associated protein 1 (YAP1) and decreased the expression of YAP1 target genes. Reactivation of YAP1 reversed AMOTL1-silencing-induced antitumor effects, whereas inhibition of YAP1 abolished AMOTL1-overexpression-induced tumor-promoting effects in glioma cells. Silencing of AMOTL1 also retarded the growth of glioma cell-derived xenograft tumors in vivo. In conclusion, these findings suggested that AMOTL1 may exert a tumor-promoting function in glioma by enhancing the activation of YAP1 signaling. This work suggested AMOTL1 as a potential target for the development of antiglioma therapy.

Angiomotins (Amot) are a family of adaptor proteins that regulate cellular differentiation and proliferation signaling. These cellular events are linked to the initiation of invasive ductal carcinoma, the most common form of breast cancer. Their characteristic coiled-coil homology (ACCH) domain selectively binds phosphatidylinositol lipids (PI), leading to membrane deformation and fusion events necessary for the trafficking polarity proteins to and from the apical membrane. We have previously shown that the ACCH domain has the ability to reorganize and homogenize the PI-enriched microdomains in membranes. However, the connection between the membrane fusion activity and the homogenization of PI has not been well described. In this study, we use small angle x-ray scattering (SAXS) to demonstrate the lipid reorganization function and fluorescence resonance energy transfer (FRET) to characterize the vesicle fusion activity. As a result, we found 6 mutations in the ACCH domain that caused a loss of fusion activity. Furthermore, these mutations also have lost lipid reorganization activity. The results presented provide insight into the role of the Amot ACCH domain residues in driving membrane fusion events involved in targeting and recycling cellular polarity proteins to maintain normal cellular phenotypes.

Objective Circular RNA (circRNA) plays a vital role in the development and progression of malignancies, however, the function of circRNAs in cholangiocarcinoma (CCA) remains unexplored. The aim of this study was to investigate circRNA expression in CCA versus para-cancer tissues, and elucidate any potential associated mechanisms. Methods Differential expression of circRNAs between CCA and para-cancer tissue was analysed by microarray hybridization, and validated by real-time quantitative reverse transcription–polymerase chain reaction (qRT–PCR). The downstream pathway was investigated using bioinformatics and qRT–PCR. Results Microarray hybridization revealed 10 circRNAs with > 3-fold increased expression versus para-cancer (circRNA_002172, circRNA_002144, circRNA_001588, circRNA_000166, circRNA_000585, circRNA_000167, circRNA_402608, circRNA_006853, circRNA_001589, circRNA_008882), and three circRNAs with > 3-fold decreased expression (circRNA_406083, circRNA_104940, circRNA_006349). CircRNA_000585 was shown by qRT-PCR to be upregulated in tumour versus paired para-cancer tissue from 15 patients with CCA. Bioinformatics analysis revealed a potential pathway comprising circRNA_000585/microRNA-615-5p/angiomotin (AMOT)/Yes associated protein 1 (YAP) in CCA. RT–PCR validation of crucial molecule expression showed downregulation of miR-615-5p, and upregulation of AMOT and YAP in CCA tumours. Conclusion Multiple circRNAs are dysregulated in CCA. CircRNA_000585 is upregulated in CCA, and may function by a circRNA_000585/miR-615-5p/AMOT/YAP pathway, which may be a novel CCA pathway.

Cells are constantly exposed to various mechanical forces, including hydrostatic pressure, cyclic stretch, fluid shear stress, and extracellular matrix stiffness. Mechanical cues can be translated into the cell-specific transcriptional process by a cellular mechanic-transducer. Evidence suggests that mechanical signals assist activated intracellular signal transduction pathways and the relative phenotypic adaptation to coordinate cell behavior and disease appropriately. The Hippo/yes-associated protein (YAP) signaling pathway is regulated in response to numerous mechanical stimuli. It plays an important role in the mechanotransduction mechanism, which converts mechanical forces to cascades of molecular signaling to modulate gene expression. This review summarizes the recent findings relevant to the Hippo/YAP pathway-based mechanotransduction in cell behavior and maintaining blood vessels, as well as cardiovascular disease.

Filoviridae family members Ebola (EBOV) and Marburg (MARV) viruses and Arenaviridae family member Lassa virus (LASV) are emerging pathogens that can cause hemorrhagic fever and high rates of mortality in humans. A better understanding of the interplay between these viruses and the host will inform about the biology of these pathogens, and may lead to the identification of new targets for therapeutic development. Notably, expression of the filovirus VP40 and LASV Z matrix proteins alone drives assembly and egress of virus-like particles (VLPs). The conserved PPxY Late (L) domain motifs in the filovirus VP40 and LASV Z proteins play a key role in the budding process by mediating interactions with select host WW-domain containing proteins that then regulate virus egress and spread. To identify the full complement of host WW-domain interactors, we utilized WT and PPxY mutant peptides from EBOV and MARV VP40 and LASV Z proteins to screen an array of GST-WW-domain fusion proteins. We identified WW domain-containing oxidoreductase (WWOX) as a novel PPxY-dependent interactor, and we went on to show that full-length WWOX physically interacts with eVP40, mVP40 and LASV Z to negatively regulate egress of VLPs and of a live VSV/Ebola recombinant virus (M40). Interestingly, WWOX is a versatile host protein that regulates multiple signaling pathways and cellular processes via modular interactions between its WW-domains and PPxY motifs of select interacting partners, including host angiomotin (AMOT). Notably, we demonstrated recently that expression of endogenous AMOT not only positively regulates egress of VLPs, but also promotes egress and spread of live EBOV and MARV. Toward the mechanism of action, we show that the competitive and modular interplay among WWOX-AMOT-VP40/Z regulates VLP and M40 virus egress. Thus, WWOX is the newest member of an emerging group of host WW-domain interactors (e.g. BAG3; YAP/TAZ) that negatively regulate viral egress. These findings further highlight the complex interplay of virus-host PPxY/WW-domain interactions and their potential impact on the biology of both the virus and the host during infection.Author SummaryFiloviruses (Ebola [EBOV] and Marburg [MARV]) and arenavirus (Lassa virus; LASV) are zoonotic, emerging pathogens that cause outbreaks of severe hemorrhagic fever in humans. A fundamental understanding of the virus-host interface is critical for understanding the biology of these viruses and for developing future strategies for therapeutic intervention. Here, we identified host WW-domain containing protein WWOX as a novel interactor with VP40 and Z, and showed that WWOX inhibited budding of VP40/Z virus-like particles (VLPs) and live virus in a PPxY/WW-domain dependent manner. Our findings are important to the field as they expand the repertoire of host interactors found to regulate PPxY-mediated budding of RNA viruses, and further highlight the competitive interplay and modular virus-host interactions that impact both the virus lifecycle and the host cell.

Summary Small-molecule tankyrase 1 and tankyrase 2 (TNKS1/2) inhibitors are effective antitumor agents in selected tumor cell lines and mouse models. Here, we characterized the response signatures and the in-depth mechanisms for the antiproliferative effect of tankyrase inhibition (TNKSi). The TNKS1/2-specific inhibitor G007-LK was used to screen 537 human tumor cell lines and a panel of particularly TNKSi-sensitive tumor cell lines was identified. Transcriptome, proteome, and bioinformatic analyses revealed the overall TNKSi-induced response signatures in the selected panel. TNKSi-mediated inhibition of wingless-type mammary tumor virus integration site/β-catenin, yes-associated protein 1 (YAP), and phosphatidylinositol-4,5-bisphosphate 3-kinase/AKT signaling was validated and correlated with lost expression of the key oncogene MYC and impaired cell growth. Moreover, we show that TNKSi induces accumulation of TNKS1/2-containing β-catenin degradasomes functioning as core complexes interacting with YAP and angiomotin proteins during attenuation of YAP signaling. These findings provide a contextual and mechanistic framework for using TNKSi in anticancer treatment that warrants further comprehensive preclinical and clinical evaluations., Graphical abstract, Highlights • TNKSi-responding tumor cell lines were identified • TNKSi targets WNT/β-catenin, YAP, and PI3K/AKT signaling • Reduced MYC expression leads to impaired tumor cell growth, Proteomics; Cancer; Transcriptomics

Vascular development is a complex multistep process involving the coordination of cellular functions such as migration, proliferation and differentiation. Understanding the underlying mechanisms of these processes is of importance due to involvement of vessel expansion in various pathologies. How mechanical forces generated by cells and transmission of these physical forces control vascular development is poorly understood. Using an endothelial-specific genetic model in mice, we show that deletion of the scaffold protein, Angiomotin (Amot), inhibits migration and expansion of physical and pathological vascular network. We further show that Amot is required for tip cell migration and the extension of cellular filopodia. Exploiting in vivo and in vitro molecular approaches, we show that Amot binds talin and is essential for relaying forces between fibronectin and the cytoskeleton. Finally, we provide evidence that Amot is a novel component of the endothelial integrin adhesome and propose that Amot integrates spatial cues from the extra-cellular matrix in order to form a functional vascular network.

Angiomotins are a family of molecular scaffolding proteins that function to organize contact points (called tight junctions in vertebrates) between adjacent cells. Some angiomotin isoforms bind to the actin cytoskeleton and are part of signaling pathways that influence cell morphology and migration. Others cooperate with components of the Hippo signaling pathway and the associated networks to control organ growth. The 130-kDa isoform, AMOT-p130, has critical roles in neural stem cell differentiation, dendritic patterning, and synaptic maturation-attributes that are essential for normal brain development and are consistent with its association with autism. Here, we review and discuss the evidence that supports a role for AMOT-p130 in neuronal development in the central nervous system.

Enrichment of Angiomotin (AMOT) in the ectoplacental cone of E7.5 murine placenta prompted our investigation on the role of AMOT in trophoblast differentiation. We show here that AMOT levels increased in mouse placenta during gestation and also upon induction of differentiation in trophoblast stem cell ex vivo. Proteomic data unravelling AMOT-interactome in trophoblast cells indicated a majority of AMOT interactors to be involved in protein translation. In depth analysis of AMOT-interactome led to identification of eukaryotic translation initiation factor 4A (eIF4A) as the most plausible AMOT interactor. Loss of function of AMOT enhanced, whereas, gain in function resulted in decline of global protein synthesis in trophoblast cells. Bioinformatics analysis evaluating the potential energy of AMOT-eIF4A binding suggested a strong AMOT-eIF4A interaction using a distinct groove encompassing amino acid residue positions 238-255 of AMOT. Co-immunoprecipitation of AMOT with eIF4A re-affirmed AMOT-eIF4A association in trophoblast cells. Deletion of 238-255 amino acids of AMOT resulted in abrogation of AMOT-eIF4A interaction. In addition, 238-255 amino acid deletion of AMOT was ineffective in eliciting AMOT's function in reducing global protein synthesis. Interestingly, AMOT dependent sequestration of eIF4A dampened its loading to the m7 -GTP cap and hindered its interaction with eIF4G. Furthermore, enhanced AMOT expression in placenta was associated with intra-uterine growth restriction in both rats and humans. These results not only highlight a hitherto unknown novel function of AMOT in trophoblast cells but also have broad biological implications as AMOT might be an inbuilt switch to check protein synthesis in developmentally indispensable trophoblast cells. © AlphaMed Press 2020 SIGNIFICANCE STATEMENT: Trophoblast cells, the parenchymal cells of placenta, execute most placental functions, indispensible for successful pregnancy. They arise from the trophoblast stem cell (TSC) niche during development. TSCs are recognized as the developmental counterpart of ES cells in the context of placental development. Inadequate, trophoblast differentiation leads to adverse pregnancy outcome, which is a global health concern. Expanding the knowledge on the regulatory circuits of trophoblast development is therefore essential to improve the success of pregnancy.

Angiomotin (AMOT) is a membrane protein that is aberrantly expressed in a variety of solid tumors. Accumulating evidence support that AMOT is involved in the pathological processes of tumor proliferation, apoptosis, and invasion. However, the potential role of AMOT in the pathogenesis of diffuse large B-cell lymphoma (DLBCL) remains elusive. In the present study, we investigated the expression level and biological function of AMOT in DLBCL. AMOT expression was significantly reduced in DLBCL biopsy section, and low AMOT expression was associated with poor clinical prognosis. Overexpression of AMOT by lentivirus in human DLBCL cells induced cell viability inhibition concomitant with an increased percentage of cells in G1 phase and decreased percentage in S phase. Moreover, AMOT upregulation increased the sensitivity of DLBCL cells to doxorubicin. Furthermore, overexpression of AMOT led to reduced activation of key kinases for the DNA damage response (DDR). The above results indicated that AMOT acts as a tumor suppressor via inhibition of the DDR, thus reducing the viability while increasing the chemosensitivity in DLBCL. In summary, AMOT may be a novel potential target for DLBCL therapeutic intervention.

Summary: The Hippo/Yes-associated protein (YAP) pathway has pivotal roles in innate immune responses against pathogens in macrophages. However, the role of YAP in macrophages during atherosclerosis and its mechanism of YAP activation remain unknown. Here, we find that YAP overexpression in myeloid cells aggravates atherosclerotic lesion size and infiltration of macrophages, whereas YAP deficiency reduces atherosclerotic plaque. Tumor necrosis factor receptor-associated factor 6 (TRAF6), a downstream effector of interleukin-1β (IL-1β), triggers YAP ubiquitination at K252, which interrupts the interaction between YAP and angiomotin and results in enhanced YAP nuclear translocation. The recombinant IL-1 receptor antagonist anakinra reduces atherosclerotic lesion formation, which is abrogated by YAP overexpression. YAP level is increased in human and mouse atherosclerotic vessels, and plasma IL-1β level in patients with STEMI is correlated with YAP protein level in peripheral blood mononuclear cells. These findings elucidate a mechanism of YAP activation, which might be a therapeutic target for atherosclerosis.

Diabetic retinopathy (DR) is the most severe microvascular complication of diabetes and a major cause of visual impairment and blindness. However, the treatment for DR is still limited. Our study aimed to explore the role of circular RNA_0002570 in DR. First, we predicted the potential microRNA and mRNA that could bind to circ_0002570 and identified the miR-1243 and angiomotin gene; then, we used RT-PCR and Western blot to measure their expression. Next, we evaluated the abilities of proliferation, migration, and angiogenesis in vitro in human retinal microvascular endothelial cells (hRMECs) by CCK-8, transwell assay, and tube formation assay, respectively. To analyze the relationship among miR-1243, circ_0002570, and angiomotin, RNA pull-down and luciferase assay were performed. Our results showed that, in DR patients and high-glucose–induced hRMECs, miR-1243, circ_0002570, and angiomotin were all abnormally expressed. MiR-1243 could directly and competitively bind to both circ_0002570 and angiomotin mRNA to inhibit their expression. Moreover, circ_0002570 suppressed the abilities of proliferation, migration, and angiogenesis in hRMECs induced by high glucose, which was dependent on miR-1243-angiomotin axis. Furthermore, circ_0002570 could upregulate angiomotin by targeting miR-1243 to mediate the dysfunction of hRMECs induced by high glucose. In conclusion, circ_0002570 might serve as a potential target for diagnosis and treatment for DR.

Endothelial cell VCAM-1 regulates recruitment of lymphocytes, eosinophils, mast cells, or dendritic cells during allergic inflammation. In this report, we demonstrated that, during allergic lung responses, there was reduced zonula occludens (ZO)-1 localization in lung endothelial cell junctions, whereas there was increased lung endothelial cell expression of VCAM-1, N-cadherin, and angiomotin. In vitro, leukocyte binding to VCAM-1 reduced ZO-1 in endothelial cell junctions. Using primary human endothelial cells and mouse endothelial cell lines, Ab crosslinking of VCAM-1 increased serine phosphorylation of ZO-1 and induced dissociation of ZO-1 from endothelial cell junctions, demonstrating that VCAM-1 regulates ZO-1. Moreover, VCAM-1 induction of ZO-1 phosphorylation and loss of ZO-1 localization at cell junctions was blocked by inhibition of VCAM-1 intracellular signals that regulate leukocyte transendothelial migration, including NOX2, PKCα, and PTP1B. Furthermore, exogenous addition of the VCAM-1 signaling intermediate H2O2 (1 μM) stimulated PKCα-dependent and PTP1B-dependent serine phosphorylation of ZO-1 and loss of ZO-1 from junctions. Overexpression of ZO-1 blocked leukocyte transendothelial migration. In summary, leukocyte binding to VCAM-1 induces signals that stimulated ZO-1 serine phosphorylation and reduced ZO-1 localization at endothelial cell junctions during leukocyte transendothelial migration. VCAM-1 signaling through ROS, PKCalpha, and PTP1B induce serine phosphorylation of ZO-1 and loss of ZO-1 from endothelial cell junctions during VCAM-1-dependent leukocyte transendothelial migration.

Angiogenesis is a complex, multistep process involving dynamic changes in endothelial cell (EC) shapes and behaviors, especially in specialized cell types such as tip cells (with active filopodial extensions), stalk cells (with less motility) and phalanx cells (with stable junction connections). The Hippo-Yes-associated protein (YAP)/ transcription activator with PDZ binding motif (TAZ) signaling plays a critical role in development, regeneration and organ size by regulating cell-cell contact and actin cytoskeleton dynamics. Recently, with the finding that YAP is expressed in the front edge of the developing retinal vessels, Hippo-YAP/TAZ signaling has emerged as a new pathway for blood vessel development. Intriguingly, the LATS1/2-mediated angiomotin (AMOT) family and YAP/TAZ activities contribute to EC shapes and behaviors by spatiotemporally modulating actin cytoskeleton dynamics and EC junction stability. Herein, we summarize the recent understanding of the role of Hippo-YAP/TAZ signaling in the processes of EC sprouting and junction maturation in angiogenesis. [BMB Reports 2018; 51(3): 157-162].

Angiomotin (Amot) is a newly discovered, multifunctional protein that is involved in cell migration and angiogenesis. However, the role of its isoform, AmotP130, in the regulation of cytoskeleton and metastasis of breast cancer, is unclear. The aim of this study was to investigate the role of AmotP130 in the reorganization of the actin cytoskeleton and the changes of morphology in breast cancer cells through the Rho pathway that influences the invasion and migration of cells. The results suggested that AmotP130 suppressed the invasion ability through remodelling the cytoskeleton of breast cancer cells, including the actin fibre organization and focal adhesion protein turnover. Global transcriptome changes in breast cancer cells following knockdown of AmotP130 identified pathways related with the cytoskeleton and cell motility that involved the Rho GTPase family. From database analyses, changes in the Rho GTPase family of proteins were identified as possible prognostic factors in patients with breast cancer. We have been suggested that AmotP130 suppressed the invasion ability through remodelling of the cytoskeleton of breast cancer cells, involving regulation of the Rho pathway. The cytoskeleton‐related pathway components may provide novel, clinically therapeutic targets for breast cancer treatment.