The physiological role of Motin family and its dysregulation in tumorigenesis

Induced expression of AMOT reverses adriamycin resistance in breast cancer cells

Adriamycin (ADR) is widely used against breast cancer, but subsequent resistance always occurs. YAP, a downstream protein of angiomotin (AMOT), importantly contributes to ADR resistance, whereas the mechanism is largely unknown. MCF-7 cells and MDA-MB-231 cells were used to establish ADR-resistant cell. Then, mRNA and protein expressions of AMOT and YAP expressions were determined. After AMOT transfection alone or in combination with YAP, the sensitivity of the cells to ADR were evaluated in vitro by examining cell proliferation, apoptosis, and cell cycle, as well as in vivo by examining tumor growth. Additionally, the expressions of proteins in YAP pathway were determined in AMOT-overexpressing cells. In the ADR-resistant cells, the expression of AMOT was decreased while YAP was increased, respectively, and the nucleus localization of YAP was increased at the same time. After AMOT overexpression, these were inhibited, whereas the cell sensitivity to ADR was enhanced. However, the AMOT-induced changes were significantly suppressed by YAP knockdown. The consistent results in vivo showed that AMOT enhanced the inhibition of ADR on tumor growth, and inhibited YAP signaling, evidenced by decreased levels of YAP, CycD1, and p-ERK. Our data revealed that decreased AMOT contributed to ADR resistance in breast cancer cells, which was importantly negatively mediated YAP. These observations provide a potential therapy against breast cancer with ADR resistance.

Upregulation of Angiomotin-Like 2 Ameliorates Experimental Pulmonary Arterial Hypertension by Inactivating YAP1 Signaling

ABSTRACT

Angiomotin-like 2 (AMOTL2) is related to numerous physiological and pathological conditions by affecting signal transduction. However, whether AMOTL2 is linked to pulmonary arterial hypertension (PAH) has not been addressed. This work aimed to investigate the potential role of AMOTL2 in PAH. A decrease in AMOTL2 abundance was observed in the lungs of PAH rats. The upregulation of AMOTL2 significantly decreased right ventricle systolic pressure and right ventricular hypertrophy in PAH rats. Overexpression of AMOTL2 also led to a noteworthy decrease in vascular wall thickness, pulmonary artery area, and collagen deposition in rats with PAH. AMOTL2 was downregulated in hypoxia-stimulated pulmonary arterial smooth muscle cells (PASMCs). Moreover, AMOTL2 overexpression impeded hypoxia-evoked proliferation, migration, and phenotypic transformation in rat PASMCs. Mechanistic investigation revealed that Yes-associated protein 1 (YAP1) activation in PAH rats or hypoxia-stimulated PASMCs was markedly inhibited by AMOTL2 overexpression, which was associated with increased large tumor suppressor 1/2 phosphorylation. The inhibition of large tumor suppressor 1/2 reversed the AMOTL2-mediated inactivation of YAP1. Restoring the activity of YAP1 reversed the inhibitory effect of AMOTL2 on hypoxia-evoked proliferation, migration, and phenotypic transformation of PASMCs. Collectively, these results suggest that AMOTL2 can ameliorate PAH in a rat model by interfering with pulmonary arterial remodeling via the inactivation of YAP1 signaling. Our work indicates that AMOTL2 may be a candidate target for novel drug development for the treatment of PAH.

WWC1/2 regulate spinogenesis and cognition in mice by stabilizing AMOT

WWC1 regulates episodic learning and memory, and genetic nucleotide polymorphism of WWC1 is associated with neurodegenerative diseases such as Alzheimer's disease. However, the molecular mechanism through which WWC1 regulates neuronal function has not been fully elucidated. Here, we show that WWC1 and its paralogs (WWC2/3) bind directly to angiomotin (AMOT) family proteins (Motins), and recruit USP9X to deubiquitinate and stabilize Motins. Deletion of WWC genes in different cell types leads to reduced protein levels of Motins. In mice, neuron-specific deletion of Wwc1 and Wwc2 results in reduced expression of Motins and lower density of dendritic spines in the cortex and hippocampus, in association with impaired cognitive functions such as memory and learning. Interestingly, ectopic expression of AMOT partially rescues the neuronal phenotypes associated with Wwc1/2 deletion. Thus, WWC proteins modulate spinogenesis and cognition, at least in part, by regulating the protein stability of Motins.

Breast Cancer Therapeutics and Hippo Signaling Pathway: Novel MicroRNA-Gene-Protein Interaction Networks

The Hippo signaling pathway is a master regulator of development, cell proliferation, and apoptosis in particular, and it plays an important role in tissue regeneration, controlling organ size, and cancer suppression. Dysregulation of the Hippo signaling pathway has been implicated in breast cancer, a highly prevalent cancer affecting 1 out of every 15 women worldwide. While the Hippo signaling pathway inhibitors are available, they are suboptimal, for example, due to chemoresistance, mutation, and signal leakage. Inadequate knowledge about the Hippo pathway connections and their regulators limits our ability to uncover novel molecular targets for drug development. We report here novel microRNA (miRNA)-gene and protein-protein interaction networks in the Hippo signaling pathway. We employed the GSE miRNA dataset for the present study. The GSE57897 dataset was normalized and searched for differentially expressed miRNAs, and their targets were searched using the miRWalk2.0 tool. From the upregulated miRNAs, we observed that the hsa-miR-205-5p forms the biggest cluster and targets four genes involved in the Hippo signaling pathway. Interestingly, we found a novel connection between two Hippo signaling pathway proteins, angiomotin (AMOT) and mothers against decapentaplegic homolog 4 (SMAD4). From the downregulated miRNAs, hsa-miR-16-5p, hsa-miR-7g-5p, hsa-miR-141-3p, hsa-miR-103a-3p, hsa-miR-21-5p, and hsa-miR-200c-3p, target genes were present in the pathway. We found that PTEN, EP300, and BTRC were important cancer-inhibiting proteins, form hubs, and their genes interact with downregulating miRNAs. We suggest that targeting proteins from these newly unraveled networks in the Hippo signaling pathway and further research on the interaction of hub-forming cancer-inhibiting proteins can open up new avenues for next-generation breast cancer therapeutics.

A mutational hotspot in AMOTL1 defines a new syndrome of orofacial clefting, cardiac anomalies, and tall stature

AMOTL1 encodes angiomotin-like protein 1, an actin-binding protein that regulates cell polarity, adhesion, and migration. The role of AMOTL1 in human disease is equivocal. We report a large cohort of individuals harboring heterozygous AMOTL1 variants and define a core phenotype of orofacial clefting, congenital heart disease, tall stature, auricular anomalies, and gastrointestinal manifestations in individuals with variants in AMOTL1 affecting amino acids 157-161, a functionally undefined but highly conserved region. Three individuals with AMOTL1 variants outside this region are also described who had variable presentations with orofacial clefting and multi-organ disease. Our case cohort suggests that heterozygous missense variants in AMOTL1, most commonly affecting amino acid residues 157-161, define a new orofacial clefting syndrome, and indicates an important functional role for this undefined region.

The role of Motin family proteins in tumorigenesis-an update

The Motin protein family consists of three members: AMOT (p80 and p130 isoforms), AMOT-like protein 1 (AMOTL1), and AMOT-like protein 2 (AMOTL2). The family members play an important role in processes such as cell proliferation, migration, angiogenesis, tight junction formation, and cell polarity. These functions are mediated through the involvement of the Motins in the regulation of different signal transduction pathways, including those regulated by small G-proteins and the Hippo-YAP pathway. One of the more characterized aspects of Motin family function is their role in regulating signaling through the Hippo-YAP pathway, and while some studies suggest a YAP-inhibitory function other studies indicate the Motins are required for YAP activity. This duality is also reflected in previous reports, often contradictory, that suggest the Motin proteins can function as oncogenes or tumor suppressors in tumorigenesis. In this review we summarize recent findings and integrate that with the existing work describing the multifunctional role of the Motins in different cancers. The emerging picture suggests that the Motin protein function is cell-type and context dependent and that further investigation in relevant cell types and whole organism models is required for the elucidation of the function of this protein family.

CircAMOTL1 RNA and AMOTL1 Protein: Complex Functions of AMOTL1 Gene Products

The complexity of the cellular proteome facilitates the control of a wide range of cellular processes. Non-coding RNAs, including microRNAs and long non-coding RNAs, greatly contribute to the repertoire of tools used by cells to orchestrate various functions. Circular RNAs (circRNAs) constitute a specific class of non-coding RNAs that have recently emerged as a widely generated class of molecules produced from many eukaryotic genes that play essential roles in regulating cellular processes in health and disease. This review summarizes current knowledge about circRNAs and focuses on the functions of AMOTL1 circRNAs and AMOTL1 protein. Both products from the AMOTL1 gene have well-known functions in physiology, cancer, and other disorders. Using AMOTL1 as an example, we illustrate how focusing on both circRNAs and proteins produced from the same gene contributes to a better understanding of gene functions.

Soluble CD146, a biomarker and a target for preventing resistance to anti-angiogenic therapy in glioblastoma

Rationale

Glioblastoma multiforme (GBM) is a primary brain tumor with poor prognosis. The U.S. food and drug administration approved the use of the anti-VEGF antibody bevacizumab in recurrent GBM. However, resistance to this treatment is frequent and fails to enhance the overall survival of patients. In this study, we aimed to identify novel mechanism(s) responsible for bevacizumab-resistance in CD146-positive glioblastoma.

Methods

The study was performed using sera from GBM patients and human GBM cell lines in culture or xenografted in nude mice.

Results

We found that an increase in sCD146 concentration in sera of GBM patients after the first cycle of bevacizumab treatment was significantly associated with poor progression free survival and shorter overall survival. Accordingly, in vitro treatment of CD146-positive glioblastoma cells with bevacizumab led to a high sCD146 secretion, inducing cell invasion. These effects were mediated through integrin αvβ3 and were blocked by mucizumab, a novel humanized anti-sCD146 antibody. In vivo, the combination of bevacizumab with mucizumab impeded CD146 + glioblastoma growth and reduced tumor cell dissemination to an extent significantly higher than that observed with bevacizumab alone.

Conclusion

We propose sCD146 to be 1/ an early biomarker to predict and 2/ a potential target to prevent bevacizumab resistance in patients with glioblastoma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40478-022-01451-3.

Game-theoretic link relevance indexing on genome-wide expression dataset identifies putative salient genes with potential etiological and diapeutics role in colorectal cancer

Diapeutics gene markers in colorectal cancer (CRC) can help manage mortality caused by the disease. We applied a game-theoretic link relevance Index (LRI) scoring on the high-throughput whole-genome transcriptome dataset to identify salient genes in CRC and obtained 126 salient genes with LRI score greater than zero. The biomarkers database lacks preliminary information on the salient genes as biomarkers for all the available cancer cell types. The salient genes revealed eleven, one and six overrepresentations for major Biological Processes, Molecular Function, and Cellular components. However, no enrichment with respect to chromosome location was found for the salient genes. Significantly high enrichments were observed for several KEGG, Reactome and PPI terms. The survival analysis of top protein-coding salient genes exhibited superior prognostic characteristics for CRC. MIR143HG, AMOTL1, ACTG2 and other salient genes lack sufficient information regarding their etiological role in CRC. Further investigation in LRI methodology and salient genes to augment the existing knowledge base may create new milestones in CRC diapeutics.

Hippo signaling pathway: A comprehensive gene expression profile analysis in breast cancer

Breast cancer (BC) is the most frequently diagnosed malignancy in women and a major public health concern. The Hippo pathway is an evolutionarily conserved signaling pathway that serves as a key regulator for a wide variety of biological processes. Hippo signaling has been shown to have both oncogenic and tumor-suppressive functions in various cancers. Core components of the Hippo pathway consist of various kinases and downstream effectors such as YAP/TAZ. In the current report, differential expression of Hippo pathway elements as well as the correlation of Hippo pathway mRNAs with various clinicopathologic characteristics, including molecular subtypes, receptor status, and methylation status, has been investigated in BC using METABRIC and TCGA datasets. In this review, we note deregulation of several Hippo signaling elements in BC patients. Moreover, we see examples of negative correlations between methylation of Hippo genes and mRNA expression. The expression of Hippo genes significantly varies between different receptor subgroups. Because of the clear associations between mRNA expression and methylation status, DNA methylation may be one of the mechanisms that regulate the Hippo pathway in BC cells. Differential expression of Hippo genes among various BC molecular subtypes suggests that Hippo signaling may function differently in different subtypes of BC. Our data also highlights an interesting link between Hippo components' transcription and ER negativity in BC. In conclusion, substantial deregulation of Hippo signaling components suggests an important role of these genes in breast cancer.

FKBP51, AmotL2 and IQGAP1 Involvement in Cilastatin Prevention of Cisplatin-Induced Tubular Nephrotoxicity in Rats

The immunophilin FKBP51, the angiomotin AmotL2, and the scaffoldin IQGAP1 are overexpressed in many types of cancer, with the highest increase in leucocytes from patients undergoing oxaliplatin chemotherapy. Inflammation is involved in the pathogenesis of nephrotoxicity induced by platinum analogs. Cilastatin prevents renal damage caused by cisplatin. This functional and confocal microscopy study shows the renal focal-segmental expression of TNFα after cisplatin administration in rats, predominantly of tubular localization and mostly prevented by co-administration of cilastatin. FKBP51, AmotL2 and IQGAP1 protein expression increases slightly with cilastatin administration and to a much higher extent with cisplatin, in a cellular- and subcellular-specific manner. Kidney tubule cells expressing FKBP51 show either very low or no expression of TNFα, while cells expressing TNFα have low levels of FKBP51. AmotL2 and TNFα seem to colocalize and their expression is increased in tubular cells. IQGAP1 fluorescence increases with cilastatin, cisplatin and joint cilastatin-cisplatin treatment, and does not correlate with TNFα expression or localization. These data suggest a role for FKBP51, AmotL2 and IQGAP1 in cisplatin toxicity in kidney tubules and in the protective effect of cilastatin through inhibition of dehydropeptidase-I.

Multivalent Angiomotin-like 1 and Yes-associated protein form a dynamic complex

Multivalent complexes formed between the cancer-promoting transcriptional co-activator, Yes-associated protein (YAP), and proteins containing short linear motifs of type PPxY modulate cell proliferation and are attractive therapeutic targets. However, challenges producing PPxY polypeptides containing the full binding domain has limited understanding of the assembly process. Here, we successfully produced a polypeptide containing the complete set of three PPxY binding sites of Angiomotin-like 1 (AMOTL1), a scaffolding protein that regulates the nucleo-cytoplasmic shuttling of YAP via WW-PPxY interactions. Using an array of biophysical techniques including isothermal titration calorimetry, size-exclusion chromatography coupled to multi-angle light scattering, and solution nuclear magnetic resonance spectroscopy, we show that the AMOTL1 polypeptide is partially disordered, and binds the YAP WW domains to form an ensemble of complexes of varying stabilities. The binding process is initiated by the binding of one YAP WW domain to one AMOTL1 PPxY motif and is completed by transient interactions of the second YAP WW domain with a second AMOTL1 PPxY motif to form an equilibrating mixture composed of various species having two YAP sites bound to two conjugate AMOTL1 sites. We rationalize that the transient interactions fine-tune the stability of the complex for rapid assembly and disassembly in response to changes in the local cellular environment.

Fragment-based exploration of the 14-3-3/Amot-p130 interface

The modulation of protein-protein interactions (PPIs) has developed into a well-established field of drug discovery. Despite the advances achieved in the field, many PPIs are still deemed as ‘undruggable’ targets and the design of PPIs stabilizers remains a significant challenge. The application of fragment-based methods for the identification of drug leads and to evaluate the ‘tractability’ of the desired protein target has seen a remarkable development in recent years. In this study, we explore the molecular characteristics of the 14-3-3/Amot-p130 PPI and the conceptual possibility of targeting this interface using X-ray crystallography fragment-based screening. We report the first structural elucidation of the 14-3-3 binding motif of Amot-p130 and the characterization of the binding mode and affinities involved. We made use of fragments to probe the ‘ligandability’ of the 14-3-3/Amot-p130 composite binding pocket. Here we disclose initial hits with promising stabilizing activity and an early-stage selectivity toward the Amot-p130 motifs over other representatives 14-3-3 partners. Our findings highlight the potential of using fragments to characterize and explore proteins' surfaces and might provide a starting point toward the development of small molecules capable of acting as molecular glues.

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Phosphorylation of Ser 175 mediates binding of Amot-p130 to 14-3-3.

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The crystal structure of the 14-3-3σΔC/Amot-p130 peptide complex describes the interface.

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A fragment-based exploration of the interface assesses ‘ligandability’.

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Fragments binding at the 14-3-3/Amot-p130 interface display an initial stabilizing activity.

Angiomotin-like 1 plays a tumor-promoting role in glioma by enhancing the activation of YAP1 signaling

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.

Effects of YAP1 and SFRP2 overexpression on the biological behavior of colorectal cancer cells and their molecular mechanisms

Background

Colorectal cancer (CRC) is one of the most common malignancies worldwide and has a high mortality rate. With the development of tumor molecular biology, more and more attention is being paid to the mechanisms of cell pathways in colorectal carcinogenesis, such as the Hippo/Yes-associated protein 1 (YAP1) and Wnt/β-catenin signaling pathways. The abnormal expression of YAP1 and β-catenin have been reported in CRC, and can lead to excessive cell proliferation, and eventually, tumor formation. Secreted frizzled-related protein 2 (SFRP2) levels have been found to be decreased in a variety of cancers, and SFRP2 is an antagonist that binds directly to Wnt signal. At present, the molecular basis of colorectal tumors is still not fully understood. In the present study, we sought to identify the molecular mechanisms underlying YAP1 and SFRP2 in the development of CRC.

Methods

We constructed CRC cell lines that stably overexpressed YAP1 and SFRP2 using lentivirus packaging and cell infection. The levels of expression of the proteins were evaluated by western blot and immunofluorescence assays. Protein complex immunoprecipitation (Co-IP) was used to detect the interaction between YAP1, SFRP2, and β-catenin. The functional roles of YAP1 and SFRP2 in CRC was determined by a Cell Counting Kit-8 (CCK8) proliferation assay and flow cytometric apoptosis assay.

Results

The data of the present study showed that the overexpression of SFRP2 promoted the expression of YAP1 and β-catenin protein, and the overexpression of YAP1 promoted the expression of β-catenin protein. YAP1 overexpression promoted cell proliferation, while SFRP2 overexpression inhibited cell proliferation and promoted cell apoptosis.

Conclusions

Our findings showed that the expression of YAP1, SFRP2, and β-catenin is correlated in CRC cells. The Hippo pathway and Wnt pathway interact with each other in the pathogenesis of CRC, and YAP1 and SFRP2 are involved in the formation and development of CRC.

Potential mechanism of circRNA_000585 in cholangiocarcinoma

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.

AMOTL2‑knockdown promotes the proliferation, migration and invasion of glioma by regulating β‑catenin nuclear localization

Glioblastoma multiforme (GBM) is the most prevalent type of malignant cancer in the adult central nervous system; however, its mechanism remains unclear. Angiomotin-like 2 (AMOTL2) is a member of the motin family of angiostatin-binding proteins. It has been reported as an oncogene in cervical and breast cancer, but its association with glioma remains unknown. The aim of the present study was to investigate AMOTL2-regulated processes in glioma cell lines using extensive in vitro assays and certain bioinformatics tools. These results revealed that AMOTL2 was downregulated in high-grade glioma cells and tissues, with patients with glioma exhibiting a high AMOTL2 expression having a higher survival rate. The results of the glioma cell phenotype experiment showed that AMOTL2 suppressed GBM proliferation, migration and invasion. In addition, immunoblotting, co-immunoprecipitation and immunofluorescence assays demonstrated that AMOTL2 could directly bind to β-catenin protein, the key molecule of the Wnt signaling pathway, and regulate its downstream genes by regulating β-catenin nuclear translocation. In conclusion, the present study demonstrated that AMOTL2 inhibited glioma proliferation, migration and invasion by regulating β-catenin nuclear localization. Thus, AMOTL2 may serve as a therapeutic target to further improve the prognosis and prolong survival time of patients with glioma.

AMOT suppresses tumor progression via regulating DNA damage response signaling in diffuse large B-cell lymphoma

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.

Emerging roles for angiomotin in the nervous system

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.

De novo variant in AMOTL1 in infant with cleft lip and palate, imperforate anus and dysmorphic features

AMOTL1 belongs to the Motin family of proteins that are involved in organogenesis and tumorigenesis through regulation of cellular migration, tube formation, and angiogenesis. While involvement of all AMOTs in development or suppression of cancers is relatively well described, little is known about the congenital phenotype of pathogenic variants in these genes in humans. Recently, a heterozygous variant in AMOTL1 was published in association with orofacial clefts and cardiac abnormalities in an affected father and his daughter. However, studies in mice did not recapitulate the human phenotype and the case was summarized as inconclusive. We present a female infant with cleft lip and palate, imperforate anus and dysmorphic features, in whom trio exome sequencing revealed a de novo variant in AMOTL1 affecting a highly conserved amino acid (c.479C>T; p.[Pro160Leu]). Bioinformatic predictions and in silico modeling supported pathogenicity. This case reinforces the conjecture regarding the disruptive effect of pathogenic variants in AMOTL1 on organ formation in humans. Studies of additional families will reveal the full phenotypic spectrum associated with this multiple malformation syndrome.

Mutant Proteomics of Lung Adenocarcinomas Harboring Different EGFR Mutations

Epidermal growth factor receptor EGFR major driver mutations may affect downstream molecular networks and pathways, which would influence treatment outcomes of non-small cell lung cancer (NSCLC). This study aimed to unveil profiles of mutant proteins expressed in lung adenocarcinomas of 36 patients harboring representative driver EGFR mutations (Ex19del, nine; L858R, nine; no Ex19del/L858R, 18). Surprisingly, the orthogonal partial least squares discriminant analysis performed for identified mutant proteins demonstrated the profound differences in distance among the different EGFR mutation groups, suggesting that cancer cells harboring L858R or Ex19del emerge from cellular origins different from L858R/Ex19del-negative cells. Weighted gene coexpression network analysis, together with over-representative analysis, identified 18 coexpressed modules and their eigen proteins. Pathways enriched differentially for both the L858R and Ex19del mutations included carboxylic acid metabolic process, cell cycle, developmental biology, cellular responses to stress, mitotic prophase, cell proliferation, growth, epithelial to mesenchymal transition (EMT), and immune system. The IPA causal network analysis identified the highly activated networks of PARPBP, HOXA1, and APH1 under the L858R mutation, whereas those of ASGR1, APEX1, BUB1, and MAPK10 were highly activated under the Ex19del mutation. Interestingly, the downregulated causal network of osimertinib intervention showed the highest significance in overlap p-value among most causal networks predicted under the L858R mutation. We also identified the causal network of MAPK interacting serine/threonine kinase 1/2 (MNK1/2) highly activated differentially under the L858R mutation. Tumor-suppressor AMOT, a component of the Hippo pathways, was highly inhibited commonly under both L858R and Ex19del mutations. Our results could identify disease-related protein molecular networks from the landscape of single amino acid variants. Our findings may help identify potential therapeutic targets and develop therapeutic strategies to improve patient outcomes.

AMOTL1 enhances YAP1 stability and promotes YAP1-driven gastric oncogenesis

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.

AMOT130 drives BMP-SMAD signaling at the apical membrane in polarized cells

The large isoform of the transmembrane protein angiomotin (AMOT130) controls cell proliferation and migration of many cell types. AMOT130 associates to the actin cytoskeleton and regulates tight-junction maintenance and signaling often via endosomal uptake of polarity proteins at tight junctions. AMOT130 is highly polarized and present only at the apical side of polarized cells. Here we show that bone morphogenetic protein (BMP) growth factor signaling and AMOT function are interlinked in apical-basal polarized cells. BMP6 controls AMOT internalization and endosomal trafficking in epithelial cells. AMOT130 interacts with the BMP receptor BMPR2 and facilitates SMAD activation and target gene expression. We further demonstrate that this effect of AMOT on BMP-SMAD signaling is dependent on endocytosis and specific to the apical side of polarized epithelial and endothelial cells. Knockdown of AMOT reduces SMAD signaling only from the apical side of polarized cells, while basolateral BMP-SMAD signaling is unaffected. This allows for the first time interference with BMP signaling in a polarized manner and identifies AMOT130 as a novel BMP signaling regulator.

circAMOTL1 Motivates AMOTL1 Expression to Facilitate Cervical Cancer Growth

Cervical cancer is acknowledged as the most prevalent gynecological tumor and a severe public issue that threatens female health, resulting from its high incidence and fatality rate. Surging evidence have shown that circular RNAs (circRNAs) play significant roles in the initiation and progression of various malignancies. Although circAMOTL1 has been testified to execute oncogenic properties in breast cancer and prostate cancer, literature on its function and regulatory mechanism in cervical cancer development is still scanty. Using a bioinformatics analysis, we found circ_0004214 was a circular form of AMOTL1. Through qRT-PCR analysis, circAMOTL1 and its host gene AMOTL1 were both upregulated in cervical cancer tissues and closely correlated with poor prognosis of cervical cancer. Gain- or loss-of-function assays and in vivo experiments demonstrated that AMOTL1 promoted cervical cancer cell growth both in vitro and in vivo. Mechanically, circAMOTL1 served as a competing endogenous RNA (ceRNA) to prompt the expression of AMOTL1 through sponging miR-485-5p. Rescue assays revealed that miR-485-5p/AMOTL1 axis was involved in circ_AMOTL1-mediated cervical cancer progression. Our findings provide a better understanding of the molecular mechanism underlying circAMOTL1 in cervical cancer and indicated circAMOTL1/miR-485-5p/AMOTL1 as a promising novel therapeutic strategy for the treatment of this disease.

Role of Tricellular Tight Junction Protein Lipolysis-Stimulated Lipoprotein Receptor (LSR) in Cancer Cells

Maintaining a robust epithelial barrier requires the accumulation of tight junction proteins, LSR/angulin-1 and tricellulin, at the tricellular contacts. Alterations in the localization of these proteins temporarily cause epithelial barrier dysfunction, which is closely associated with not only physiological differentiation but also cancer progression and metastasis. In normal human endometrial tissues, the endometrial cells undergo repeated proliferation and differentiation under physiological conditions. Recent observations have revealed that the localization and expression of LSR/angulin-1 and tricellulin are altered in a menstrual cycle-dependent manner. Moreover, it has been shown that endometrial cancer progression affects these alterations. This review highlights the differences in the localization and expression of tight junction proteins in normal endometrial cells and endometrial cancers and how they cause functional changes in cells.