Differential expression of moesin in breast cancers and its implication in epithelial-mesenchymal transition

Alzheimer's disease and related tauopathies: disorders of disrupted neuronal identity

Postmitotic neurons require persistently active controls to maintain terminal differentiation. Unlike dividing cells, aberrant cell cycle activation in mature neurons causes apoptosis rather than transformation. In Alzheimer's disease (AD) and related tauopathies, evidence suggests that pathogenic forms of tau drive neurodegeneration via neuronal cell cycle re-entry. Multiple interconnected mechanisms linking tau to cell cycle activation have been identified, including, but not limited to, tau-induced overstabilization of the actin cytoskeleton, consequent changes to nuclear architecture, and disruption of heterochromatin-mediated gene silencing. Cancer- and development-associated pathways are upregulated in human and cellular models of tauopathy, and many tau-induced cellular phenotypes are also present in various cancers and progenitor/stem cells. In this review, I delve into mechanistic parallels between tauopathies, cancer, and development, and highlight the role of tau in cancer and in the developing brain. Based on these studies, I put forth a model by which pathogenic forms of tau disrupt the program that maintains terminal neuronal differentiation, driving cell cycle re-entry and consequent neuronal death. This framework presents tauopathies as conditions involving the profound toxic disruption of neuronal identity.

FBXW2 suppresses breast tumorigenesis by targeting AKT-Moesin-SKP2 axis

Oncogene Moesin plays critical role in initiation, progression, and metastasis of multiple cancers. It exerts oncogenic activity due to its high-level expression as well as posttranslational modification in cancer. However, factors responsible for its high-level expression remain elusive. In this study, we identified positive as well as negative regulators of Moesin. Our study reveals that Moesin is a cellular target of F-box protein FBXW2. We showed that FBXW2 suppresses breast cancer progression through directing proteasomal degradation of Moesin. In contrast, AKT kinase plays an important role in oncogenic function of Moesin by protecting it from FBXW2-mediated proteasomal degradation. Mechanistically, AKT phosphorylates Moesin at Thr-558 and thereby prevents its degradation by FBXW2 via weakening the association between FBXW2 and Moesin. Further, accumulated Moesin prevents FBXW2-mediated degradation of oncogene SKP2, showing that Moesin functions as an upstream regulator of oncogene SKP2. In turn, SKP2 stabilizes Moesin by directing its non-degradable form of polyubiquitination and therefore AKT-Moesin-SKP2 oncogenic axis plays crucial role in breast cancer progression. Collectively, our study reveals that FBXW2 functions as a tumor suppressor in breast cancer by restricting AKT-Moesin-SKP2 axis. Thus, AKT-Moesin-SKP2 axis may be explored for the development of therapeutics for cancer treatment.

Membrane tension-mediated stiff and soft tumor subtypes closely associated with prognosis for prostate cancer patients

BACKGROUND

Prostate cancer (PCa) is usually considered as cold tumor. Malignancy is associated with cell mechanic changes that contribute to extensive cell deformation required for metastatic dissemination. Thus, we established stiff and soft tumor subtypes for PCa patients from perspective of membrane tension.

METHODS

Nonnegative matrix factorization algorithm was used to identify molecular subtypes. We completed analyses using software R 3.6.3 and its suitable packages.

RESULTS

We constructed stiff and soft tumor subtypes using eight membrane tension-related genes through lasso regression and nonnegative matrix factorization analyses. We found that patients in stiff subtype were more prone to biochemical recurrence than those in soft subtype (HR 16.18; p < 0.001), which was externally validated in other three cohorts. The top ten mutation genes between stiff and soft subtypes were DNAH, NYNRIN, PTCHD4, WNK1, ARFGEF1, HRAS, ARHGEF2, MYOM1, ITGB6 and CPS1. E2F targets, base excision repair and notch signaling pathway were highly enriched in stiff subtype. Stiff subtype had significantly higher TMB and T cells follicular helper levels than soft subtype, as well as CTLA4, CD276, CD47 and TNFRSF25.

CONCLUSIONS

From the perspective of cell membrane tension, we found that stiff and soft tumor subtypes were closely associated with BCR-free survival for PCa patients, which might be important for the future research in the field of PCa.

Moesin is an effector of tau-induced actin overstabilization, cell cycle activation, and neurotoxicity in Alzheimer's disease

In Alzheimer's disease, neurons acquire phenotypes that are also present in various cancers, including aberrant activation of the cell cycle. Unlike cancer, cell cycle activation in post-mitotic neurons is sufficient to induce cell death. Multiple lines of evidence suggest that abortive cell cycle activation is a consequence of pathogenic forms of tau, a protein that drives neurodegeneration in Alzheimer's disease and related "tauopathies." Here we combine network analyses of human Alzheimer's disease and mouse models of Alzheimer's disease and primary tauopathy with studies in Drosophila to discover that pathogenic forms of tau drive cell cycle activation by disrupting a cellular program involved in cancer and the epithelial-mesenchymal transition (EMT). Moesin, an EMT driver, is elevated in cells harboring disease-associated phosphotau, over-stabilized actin, and ectopic cell cycle activation. We further find that genetic manipulation of Moesin mediates tau-induced neurodegeneration. Taken together, our study identifies novel parallels between tauopathy and cancer.

A biophysical perspective of the regulatory mechanisms of ezrin/radixin/moesin proteins

Many signal transductions resulting from ligand-receptor interactions occur at the cell surface. These signaling pathways play essential roles in cell polarization, membrane morphogenesis, and the modulation of membrane tension at the cell surface. However, due to the large number of membrane-binding proteins, including actin-membrane linkers, and transmembrane proteins present at the cell surface, the molecular mechanisms underlying the regulation at the cell surface are yet unclear. Here, we describe the molecular functions of one of the key players at the cell surface, ezrin/radixin/moesin (ERM) proteins from a biophysical point of view. We focus our discussion on biophysical properties of ERM proteins revealed by using biophysical tools in live cells and in vitro reconstitution systems. We first describe the structural properties of ERM proteins and then discuss the interactions of ERM proteins with PI(4,5)P₂ and the actin cytoskeleton. These properties of ERM proteins revealed by using biophysical approaches have led to a better understanding of their physiological functions in cells and tissues.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12551-021-00928-0.

High Moesin Expression Is a Predictor of Poor Prognosis of Breast Cancer: Evidence From a Systematic Review With Meta-Analysis

Owing to metastases and drug resistance, the prognosis of breast cancer is still dismal. Therefore, it is necessary to find new prognostic markers to improve the efficacy of breast cancer treatment. Literature shows a controversy between moesin (MSN) expression and prognosis in breast cancer. Here, we aimed to conduct a systematic review and meta-analysis to evaluate the prognostic relationship between MSN and breast cancer. Literature retrieval was conducted in the following databases: PubMed, Web of Science, Embase, and Cochrane. Two reviewers independently performed the screening of studies and data extraction. The Gene Expression Omnibus (GEO) database including both breast cancer gene expression and follow-up datasets was selected to verify literature results. The R software was employed for the meta-analysis. A total of 9 articles with 3,039 patients and 16 datasets with 2,916 patients were ultimately included. Results indicated that there was a significant relationship between MSN and lymph node metastases (P < 0.05), and high MSN expression was associated with poor outcome of breast cancer patients (HR = 1.99; 95% CI 1.73-2.24). In summary, there is available evidence to support that high MSN expression has valuable importance for the poor prognosis in breast cancer patients.

SYSTEMATIC REVIEW REGISTRATION

https://inplasy.com/inplasy-2020-8-0039/.

ARHGEF10L Promotes Cervical Tumorigenesis via RhoA-Mediated Signaling

Background

Rho guanine nucleotide exchange factor 10-like protein (ARHGEF10L) is a member of the guanine nucleotide exchange factor family, which regulates Rho GTPase activities, thus contributing to tumorigenesis. Our previous study demonstrated a strong association between the ARHGEF10L gene and the risk of cervical carcinoma. This study investigated the pathogenic role and mechanism of ARHGEF10L in cervical tumors.

Methods

The HeLa cell line, which was derived from cervical carcinoma, was transfected with ARHGEF10L-overexpressing plasmids or anti-ARHGEF10L siRNA. Cell counting kit-8 assays, wound-healing assays, and cell apoptosis assays were performed to investigate the effects of ARHGEF10L on cell activities. A Rho pull-down assay and RNA-sequencing analysis were performed to investigate the pathogenic pathway of ARHGEF10L involvement in cervical tumors.

Results

ARHGEF10L overexpression promoted cell proliferation and migration, reduced cell apoptosis, and induced epithelial-to-mesenchymal transition (EMT) via downregulation of E-cadherin and upregulation of N-cadherin and Slug in transfected HeLa cells. The overexpression of ARHGEF10L also upregulated GTP-RhoA, ROCK1, and phospho-ezrin/radixin/moesin (ERM) expression in HeLa cells. RNA-sequencing analysis detected altered transcription of 31 genes in HeLa cells with ARHGEF10L overexpression. Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene ontology (GO) pathway analyses identified significant differences in cyclin-dependent protein serine/threonine kinase activity, cell responses to vitamin A, and Toll-like receptor signaling pathways. Both real-time PCR and Western blotting verified the increased expression of heat shock 70 kDa protein 6 (HSPA6) in ARHGEF10L-overexpressing HeLa cells. Since we reported that ARHGEF10L played a role through RhoA-ROCK1-ERM signaling, an important pathway in tumorigenesis, and stimulated EMT and HSPA6 expression in liver tumors and gastric tumor cells, we suggest that ARHGEF10L is a novel oncogene in many tumors.

Bioinformatics analysis of lncRNA‑associated ceRNA network in melanoma

Melanoma is an extremely malignant tumor with early metastasis and high mortality. Little is known about the process of by which melanoma occurs, as its mechanism is very complex and only limited data are available on its long non-coding RNA (lncRNA)-associated competing endogenous RNAs (ceRNAs). The purpose of this study was to screen out potential prognostic molecules and identify a ceRNA network related to the occurrence of melanoma. We screened 169 differentially expressed mRNAs (DEmRNAs) from E-MTAB-1862 and GSE3189; gene ontology (GO) enrichment analysis showed that these genes were closely related to the development of skin. In the protein-protein interaction network, we screened out a total of 19 hub genes. Furthermore, we predicted the microRNAs (miRNAs) that regulate hub genes using the miRWalk database and then intersected these with GSE35579, resulting in nine DEmiRNAs. We also predicted the lncRNAs that regulate the miRNAs using the LncBasev.2 database. According to the ceRNA hypothesis, and based on the intersection of the DElncRNAs with merged GTEx and TCGA data, we obtained 20 DElncRNAs. A total of four DEmRNAs, nine DEmiRNAs, and 20 DElncRNAs were included in the ceRNA network. Based on Cox stepwise regression and survival analysis, we identified five biomarkers, ZSCAN16-AS1, LINC00520, XIST, DTL, and let-7a-5p, and obtained risk scores. The results showed that most of the differentially expressed genes were related to epithelial-mesenchymal transition (EMT) in melanoma. Finally, we obtained a LINC00520/let-7a-5p/DTL molecular regulatory network. These results suggest that ceRNA networks have an important role in evaluating the prognosis of patients with melanoma and provide a new experimental basis for exploring the EMT process in the development of melanoma.

Functional Alterations of Multidrug Resistance-Associated Proteins 2 and 5, and Breast Cancer Resistance Protein upon Snail-Induced Epithelial-Mesenchymal Transition in HCC827 Cells

Our previous report indicated that Snail-induced epithelial-mesenchymal transition (EMT) enhanced P-glycoprotein (P-gp) function and drug resistance to P-gp substrate anticancer drug in a human non-small cell lung cancer (NSCLC) cell line, HCC827. Our objective is to evaluate the changes in the mRNA and protein expression levels and the functions of multidrug resistance-associated protein (MRP) 2, MRP5 and breast cancer resistance protein (BCRP). Snail-expressing HCC827 cells showed increased mRNA levels of Snail and a mesenchymal marker vimentin, and decreased mRNA levels of an epithelial marker E-cadherin after transduction, indicating that Snail had induced EMT consistent with our previous reports. The mRNA level of MRP2 was significantly decreased, while that of MRP5 remained unchanged, in Snail-expressing cells. The expression levels of MRP2 and MRP5 proteins in whole-cell homogenate were unchanged in Snail-expressing cells, but MRP5 protein showed significantly increased membrane localization. Snail-transduction increased the efflux transport of 5-(and-6)-carboxy-2',7'-dichlorofluorescein (CDCF), a substrate of MRP2, 3 and 5. This increase was blocked by MK571, which inhibits MRP1, 2, and 5. Toxicity of cisplatin, a substrate of MRP2 and 5, was significantly decreased in Snail-expressing cells. BCRP mRNA and protein levels were both decreased in Snail-expressing cells, which showed an increase in the intracellular accumulation of 7-ethyl-10-hydroxycamptothecin (SN-38), a BCRP substrate, resulting in reduced viability. These results suggested that MRP5 function appears to be increased via an increase in membrane localization, whereas the BCRP function is decreased via a decrease in the expression level in HCC827 cells with Snail-induced EMT.

Identification of Key Pathways and Genes in Obesity Using Bioinformatics Analysis and Molecular Docking Studies

Obesity is an excess accumulation of body fat. Its progression rate has remained high in recent years. Therefore, the aim of this study was to diagnose important differentially expressed genes (DEGs) associated in its development, which may be used as novel biomarkers or potential therapeutic targets for obesity. The gene expression profile of E-MTAB-6728 was downloaded from the database. After screening DEGs in each ArrayExpress dataset, we further used the robust rank aggregation method to diagnose 876 significant DEGs including 438 up regulated and 438 down regulated genes. Functional enrichment analysis was performed. These DEGs were shown to be significantly enriched in different obesity related pathways and GO functions. Then protein-protein interaction network, target genes - miRNA regulatory network and target genes - TF regulatory network were constructed and analyzed. The module analysis was performed based on the whole PPI network. We finally filtered out STAT3, CORO1C, SERPINH1, MVP, ITGB5, PCM1, SIRT1, EEF1G, PTEN and RPS2 hub genes. Hub genes were validated by ICH analysis, receiver operating curve (ROC) analysis and RT-PCR. Finally a molecular docking study was performed to find small drug molecules. The robust DEGs linked with the development of obesity were screened through the expression profile, and integrated bioinformatics analysis was conducted. Our study provides reliable molecular biomarkers for screening and diagnosis, prognosis as well as novel therapeutic targets for obesity.

Cytoskeletal Remodeling in Cancer

Simple Summary

Cell migration is an essential process from embryogenesis to cell death. This is tightly regulated by numerous proteins that help in proper functioning of the cell. In diseases like cancer, this process is deregulated and helps in the dissemination of tumor cells from the primary site to secondary sites initiating the process of metastasis. For metastasis to be efficient, cytoskeletal components like actin, myosin, and intermediate filaments and their associated proteins should co-ordinate in an orderly fashion leading to the formation of many cellular protrusions-like lamellipodia and filopodia and invadopodia. Knowledge of this process is the key to control metastasis of cancer cells that leads to death in 90% of the patients. The focus of this review is giving an overall understanding of these process, concentrating on the changes in protein association and regulation and how the tumor cells use it to their advantage. Since the expression of cytoskeletal proteins can be directly related to the degree of malignancy, knowledge about these proteins will provide powerful tools to improve both cancer prognosis and treatment.

Abstract

Successful metastasis depends on cell invasion, migration, host immune escape, extravasation, and angiogenesis. The process of cell invasion and migration relies on the dynamic changes taking place in the cytoskeletal components; actin, tubulin and intermediate filaments. This is possible due to the plasticity of the cytoskeleton and coordinated action of all the three, is crucial for the process of metastasis from the primary site. Changes in cellular architecture by internal clues will affect the cell functions leading to the formation of different protrusions like lamellipodia, filopodia, and invadopodia that help in cell migration eventually leading to metastasis, which is life threatening than the formation of neoplasms. Understanding the signaling mechanisms involved, will give a better insight of the changes during metastasis, which will eventually help targeting proteins for treatment resulting in reduced mortality and longer survival.

Regulation of breast cancer resistance protein and P-glycoprotein by ezrin, radixin and moesin in lung, intestinal and renal cancer cell lines

Objectives

Ezrin (Ezr), radixin (Rdx) and moesin (Msn) (ERM) proteins anchor other proteins to the cell membrane, serving to regulate their localization and function. Here, we examined whether ERM proteins functionally regulate breast cancer resistance protein (BCRP) and P-glycoprotein in cell lines derived from lung, intestinal and renal cancers.

Methods

ERM proteins were each silenced with appropriate siRNA. BCRP and P-gp functions were evaluated by means of efflux and uptake assays using 7-ethyl-10-hydroxycamptothecin (SN-38) and rhodamine123 (Rho123) as specific substrates, respectively, in non-small cell lung cancer HCC827 cells, intestinal cancer Caco-2 cells and renal cancer Caki-1 cells.

Key findings

In HCC827 cells, the efflux rates of SN-38 and Rho123 were significantly decreased by knockdown of Ezr or Msn, but not Rdx. However, BCRP function was unaffected by Ezr or Rdx knockdown in Caco-2 cells, which do not express Msn. In Caki-1 cells, Rdx knockdown increased the intracellular SN-38 concentration, while knockdown of Ezr or Msn had no effect.

Conclusions

Our findings indicate that regulation of BCRP and P-gp functions by ERM proteins is organ-specific. Thus, if the appropriate ERM protein(s) are functionally suppressed, accumulation of BCRP or P-gp substrates in lung, intestine or kidney cancer tissue might be specifically increased.

Moesin is an independent prognostic marker for ER-positive breast cancer

Moesin, a cytoskeletal protein belonging to the ezrin-radixin-moesin family serves important roles in cell motility, invasion and metastasis. Moesin has been demonstrated to be of prognostic significance in tumor progression, due to its role in the metastatic process; however, its role in breast cancer is not well characterized. In the present study, the moesin expression was determined using immunohistochemistry in 404 and 46 patients with breast cancer and fibroadenoma, respectively, and the associations between moesin expression and the clinical parameters and prognostic values were analyzed. The positive rate of moesin protein expression was 47.8% (193/404) in breast cancer tissues, which was significantly higher than in fibroadenoma tissues (15.2%, 14/46). Overexpression of moesin was significantly associated with advanced clinical stage (P=0.002), positive lymph node metastasis (P<0.0001), and estrogen receptor (ER; P=0.008) and progesterone receptor (P=0.026) status. Patients with high moesin expression had significantly lower recurrence-free survival time, compared with patient with low moesin expression. Notably, overexpression of moesin was significantly associated with poor prognosis in patients with ER-positive breast cancer, and in patients treated with tamoxifen. Using a Cox proportional hazard regression model, further analysis was conducted, which demonstrated that moesin overexpression was a predictive prognostic factor for reduced overall survival time in patients with ER-positive breast cancer, and in patients treated with tamoxifen. These results indicated that moesin may be a potential marker for poor prognosis in patients with ER-positive breast cancer treated with tamoxifen. In conclusion, moesin serves an important role in the progression of breast cancer, and may be a valuable marker of breast cancer prognosis.

Behavioral remodeling of normal and cancerous epithelial cell lines with differing invasion potential induced by substrate elastic modulus

The micro-environment of cancer cells in the body is mechanically stiffer than that of normal cells. We cultured three breast cell lines of MCF10A-normal, MCF7-noninvasive, and MDA-MB-231-invasive on PDMS substrates with different elastic moduli and different cellular features were examined.Effects of substrate stiffness on cell behavior were evident among all cell lines. Cancerous cells were more sensitive to substrate stiffness for cell behaviors related to cell motility and migration which are necessary for invasion. The invasive cancerous cells were the most motile on substrates with moderate stiffness followed by non-invasive cancerous cells. Gene markers alterations were generally according to the analyzed cell movement parameters. Results suggest that alterations in matrix stiffness may be related to cancer disease and progression.

Regulation of ErbB2 localization and function in breast cancer cells by ERM proteins

The ERM protein family is implicated in processes such as signal transduction, protein trafficking, cell proliferation and migration. Consequently, dysregulation of ERM proteins has been described to correlate with carcinogenesis of different cancer types. However, the underlying mechanisms are poorly understood. Here, we demonstrate a novel functional interaction between ERM proteins and the ErbB2 receptor tyrosine kinase in breast cancer cells. We show that the ERM proteins ezrin and radixin are associated with ErbB2 receptors at the plasma membrane, and depletion or functional inhibition of ERM proteins destabilizes the interaction of ErbB2 with ErbB3, Hsp90 and Ebp50. Accompanied by the dissociation of this protein complex, binding of ErbB2 to the ubiquitin-ligase c-Cbl is increased, and ErbB2 becomes dephosphorylated, ubiquitinated and internalized. Furthermore, signaling via Akt- and Erk-mediated pathways is impaired upon ERM inhibition. Finally, interference with ERM functionality leads to receptor degradation and reduced cellular levels of ErbB2 and ErbB3 receptors in breast cancer cells.

Immunoexpression of proteins involved in cytoskeleton remodeling in benign odontogenic lesions

OBJECTIVE

The present study was designed to analyze the immunolocalization of proteins involved in cytoskeleton remodeling, such as moesin and Rho-A, in benign odontogenic lesions that present with expansive growth and invasive clinical behavior.

MATERIALS AND METHODS

Expressions of moesin and Rho-A in odontogenic epithelium were evaluated by immunohistochemical analysis in 45 odontogenic lesions using monoclonal antibodies.

RESULTS

Our results demonstrated strong membranous and cytoplasmic expressions of moesin in the epithelial cells in 66.7% and 44.4% of the odontogenic lesions, respectively. Furthermore, Rho-A expression in odontogenic epithelium was strong in the membrane and cytoplasm of 51.1% and 62.2% of the odontogenic lesions, respectively. A statistically significant correlation was found between the membranous and cytoplasmic expressions of moesin (p = 0.000) and those of Rho-A (p = 0.048) in odontogenic epithelial cells, while no statistically significant correlation was found between moesin and Rho-A expressions (p > 0.05).

CONCLUSIONS

The present study confirmed the strong expressions of moesin and Rho-A by odontogenic epithelial cells, suggesting their involvement in the development of benign odontogenic lesions. However, this study has failed to detect the connection between the moesin and Rho-A interaction in expansive growth and local invasiveness of these lesions.

The role of p53-microRNA 200-Moesin axis in invasion and drug resistance of breast cancer cells

This study aimed to analyze the expression of microRNAs in relation to p53 status in breast cancer cells and to delineate the role of Moesin in this axis. We used three isogenic breast carcinoma cell lines MCF7 (with wild-type p53), 1001 (MCF7 with mutated p53), and MCF7-E6 (MCF7 in which p53 function was disrupted). MicroRNA expression was analyzed using microarray analysis and confirmed by real-time polymerase chain reaction. The 1001 clone with mutant p53 showed 22 upregulated and 25 downregulated microRNAs. The predicted targets of these 47 microRNAs were >700 human genes belonging to interesting functional groups such as stem cell development and maintenance. The most significantly downregulated microRNAs in the p53-mutant cell line were from the miR-200 family. We focused on miR-200c which targets many transcripts involved in epithelial-to-mesenchymal transition including Moesin. We found that Moesin was expressed in 1001 but not in its p53 wild-type parental MCF7 consistent with the observed mesenchymal features in the 1001, such as vimentin positivity, E-cadherin negativity, and ZEB1 positivity in addition to the morphological changes. After Moesin silencing, the p53-mutant cells 1001 reverted from mesenchymal-to-epithelial phenotype and showed subtle reduction in migration and invasion and loss of ZEB1 and SNAIL expression. Interestingly, Moesin silencing restored the 1001 sensitivity to Doxorubicin. These results indicate that loss of miR-200c, as a consequence of p53 mutation, can upregulate Moesin oncogene and thus promote carcinogenesis. Moesin may play a role in metastasis and drug resistance of breast cancer.

Expression of ezrin and moesin in primary breast carcinoma and matched lymph node metastases

Ezrin, radixin, moesin (ERM) are important membrane-cytoskeletal crosslinkers and are suggested to play important role in cancer progression and metastasis. Even though ERM proteins were generally considered to be functionally redundant and the most studied was ezrin, recent studies highlight their distinct roles in metastatic process. Little information is available regarding the role of individual ERM proteins and their phosphorylated forms in human breast cancer. Our study is the first to examine expression of ezrin, moesin and their phosphorylated forms in primary breast tumors and matched lymph node metastases (LNMs) and their correlation with clinicopathological variables. A total of 88 primary breast cancer, 91 LNMs, 54 intraductal carcinoma and 26 normal adjacent breast tissue samples from tissue microarrays were studied. Expression was determined by immunohistochemistry, the intensity and number of positive cells was scored. Statistical analysis of protein expression and patients' age, tumor grade and hormonal status was performed. No statistical significant difference was found in ezrin, moesin, p-ezrinTyr353 and pan-p-ezrinThr567/radixinThr564/moesinThr558 expression between primary tumors and LNMs. Even though it was not significant, moesin expression varied between primary tumors, intraductal carcinoma, normal breast adjacent tissue and LNMs. A significant positive correlation between moesin and tumor grade has been proven. Even though primary tumors and matched LNMs did not show different expression patterns, moesin correlated significantly with higher tumor grade. Its positivity in intraductal carcinoma and normal breast tissue adjacent to cancer might indicate its role in tumor intiation/progression.

An HNF4α-microRNA-194/192 signaling axis maintains hepatic cell function

Hepatocyte nuclear factor 4α (HNF4α) controls the expression of liver-specific protein-coding genes. However, some microRNAs are also modulated by HNF4α, and it is not known whether they are direct targets of HNF4α and whether they influence hepatic function. In this study, we found that HNF4α regulates microRNAs, indicated by marked down-regulation of miR-194 and miR-192 (miR-194/192) in liver-specific Hnf4a-null (Hnf4a^ΔH) mice. Transactivation of the shared miR-194/192 promoter was dependent on HNF4α expression, indicating that miR-194/192 is a target gene of HNF4α. Screening of potential mRNAs targeted by miR-194/192 revealed that expression of genes involved in glucose metabolism (glycogenin 1 (Gyg1)), cell adhesion and migration (activated leukocyte cell adhesion molecule (Alcam)), tumorigenesis and tumor progression (Rap2b and epiregulin (Ereg)), protein SUMOylation (Sumo2), epigenetic regulation (Setd5 and Cullin 4B (Cln4b)), and the epithelial-mesenchymal transition (moesin (Msn)) was up-regulated in Hnf4a^ΔH mice. Moreover, we also found that miR-194/192 binds the 3'-UTR of these mRNAs. siRNA knockdown of HNF4α suppressed miR-194/192 expression in human hepatocellular carcinoma (HCC) cells and resulted in up-regulation of their mRNA targets. Inhibition and overexpression experiments with miR-194/192 revealed that Gyg1, Setd5, Sumo2, Cln4b, and Rap2b are miR-194 targets, whereas Ereg, Alcam, and Msn are miR-192 targets. These findings reveal a novel HNF4α network controlled by miR-194/192 that may play a critical role in maintaining the hepatocyte-differentiated state by inhibiting expression of genes involved in dedifferentiation and tumorigenesis. These insights may contribute to the development of diagnostic markers for early HCC detection, and targeting of the miR-194/192 pathway could be useful for managing HCC.

Hypoxia regulates ANXA1 expression to support prostate cancer cell invasion and aggressiveness

Annexin A1 (ANXA1) is a Ca²⁺-binding protein overexpressed in the invasive stages of prostate cancer (PCa) development; however, its role in this tumor metastatization is largely unknown. Moreover, hypoxic conditions in solid tumors have been related to poor prognosis in PCa patients. We have previously demonstrated that ANXA1 is implicated in the acquisition of chemo-resistant features in DU145 PCa cells conferring them a mesenchymal/metastatic phenotype. In this study, we have investigated the mechanisms by which ANXA1 regulates metastatic behavior in LNCaP, DU145 and PC3 cells exposed to hypoxia. ANXA1 was differentially expressed by PCa cell lines in normoxia whereas hypoxic stimuli resulted in a significant increase of protein expression. Additionally, in low oxygen conditions ANXA1 was extensively secreted out-side the cells where its binding to formyl peptide receptors (FPRs) induced cell invasion. Loss and gain of function experiments performed by using the RNA interfering siANXA1 and an ANXA1 over-expressing plasmid (MF-ANXA1), also confirmed the leading role of the protein in modulating LNCaP, DU145 and PC3 cell invasiveness. Finally, ANXA1 played a crucial role in the regulation of cytoskeletal dynamics underlying metastatization process, such as the loss of adhesion molecules and the occurrence of the epithelial to mesenchymal transition (EMT). ANXA1 expression increased inversely to epithelial markers such as E-cadherin and cytokeratins 8 and 18 (CKs) and proportionally to mesenchymal ones such as vimentin, ezrin and moesin. Our results indicated that ANXA1 may be a key mediator of hypoxia-related metastasis-associated processes in PCa.

Understanding cytoskeleton regulators in glioblastoma multiforme for therapy design

The cellular cytoskeleton forms the primary basis through which a cell governs the changes in size, shape, migration, proliferation, and forms the primary means through which the cells respond to their environment. Indeed, cell and tissue morphologies are used routinely not only to grade tumors but also in various high-content screening methods with an aim to identify new small molecules with therapeutic potential. This study examines the expression of various cytoskeleton regulators in glioblastoma multiforme (GBM). GBM is a very aggressive disease with a low life expectancy even after chemo- and radiotherapy. Cancer cells of GBM are notorious for their invasiveness, ability to develop resistance to chemo- and radiotherapy, and to form secondary site tumors. This study aims to gain insight into cytoskeleton regulators in GBM cells and to understand the effect of various oncology drugs, including temozolomide, on cytoskeleton regulators. We compare the expression of various cytoskeleton regulators in GBM-derived tumor and normal tissue, CD133-postive and -negative cells from GBM and neural cells, and GBM stem-like and differentiated cells. In addition, the correlation between the expression of cytoskeleton regulators with the clinical outcome was examined to identify genes associated with longer patient survival. This was followed by a small molecule screening with US Food and Drug Administration (FDA)-approved oncology drugs, and its effect on cellular cytoskeleton was compared to treatment with temozolomide. This study identifies various groups of cytoskeletal regulators that have an important effect on patient survival and tumor development. Importantly, this work highlights the advantage of using cytoskeleton regulators as biomarkers for assessing prognosis and treatment design for GBM.

MicroRNA-200b Impacts Breast Cancer Cell Migration and Invasion by Regulating Ezrin-Radixin-Moesin

BACKGROUND Ezrin-radixin-moesin (ERM) plays an important role in multiple links of tumors. It also involved in breast cancer invasion and metastasis, and might be a potential biomarker of breast cancer. Another study suggested that ERM expression was regulated directly by miR-200c, and had a critical role in miR-200c suppressing cell migration. This study aimed to investigate the effect of miR-200b on ERM expression in a breast cancer cell line and its influence on invasion and metastasis ability in vitro. MATERIAL AND METHODS Breast cancer cell lines MCF-7 and MDA-MB-231 with different metastatic potentials were selected as a model. MiR-200b overexpression or inhibition was achieved by Lipofectamine™ 2000-mediated miRNA transfection. RT-PCR was used to test miR-200b level, while Western blot was selected to detect ERM protein expression. Wound healing assay and Transwell assay were performed to determine cell migration and invasion ability. RESULTS RT-PCR revealed that miR-200b level in MDA-MB-231 was obviously lower than that in MCF-7, while Western blot analysis showed that ERM expression was significantly higher. MiR-200b inhibition by transfection in MCF-7 markedly decreased miR-200b level, elevated ERM expression, and enhanced cell migration and invasion. MiR-200b overexpression in MDA-MB-231 obviously increased miR-200b level, reduced ERM expression, and weakened cell migration and invasion. CONCLUSIONS MiR-200b participates in breast cancer cell migration and invasion through regulating ERM in MCF-7 and MDA-MB-231.

A glimpse of the ERM proteins

In all eukaryotes, the plasma membrane is critically important as it maintains the architectural integrity of the cell. Proper anchorage and interaction between the plasma membrane and the cytoskeleton is critical for normal cellular processes. The ERM (ezrin-radixin-moesin) proteins are a class of highly homologous proteins involved in linking the plasma membrane to the cortical actin cytoskeleton. This review takes a succinct look at the biology of the ERM proteins including their structure and function. Current reports on their regulation that leads to activation and deactivation was examined before taking a look at the different interacting partners. Finally, emerging roles of each of the ERM family members in cancer was highlighted.

Moesin is a major regulator of centrosome behavior in epithelial cells with extra centrosomes

Centrosome amplification has severe consequences during development and is thought to contribute to a variety of diseases such as cancer and microcephaly. However, the adverse effects of centrosome amplification in epithelia are still not known. Here, we investigate the consequences of centrosome amplification in the Drosophila wing disc epithelium. We found that epithelial cells exhibit mechanisms of clustering but also inactivation of extra centrosomes. Importantly, these mechanisms are not fully efficient, and both aneuploidy and cell death can be detected. Epithelial cells with extra centrosomes generate tumors when transplanted into WT hosts and inhibition of cell death results in tissue over-growth and disorganization. Using SILAC-fly, we found that Moesin, a FERM domain protein, is specifically upregulated in wing discs with extra centrosomes. Moesin localizes to the centrosomes and mitotic spindle during mitosis, and we show that Moesin upregulation influences extra-centrosome behavior and robust bipolar spindle formation. This study provides a mechanistic explanation for the increased aneuploidy and transformation potential primed by centrosome amplification in epithelial tissues.

•

Consequences of centrosome amplification in epithelia are discussed

•

Centrosome clustering or inactivation is not fully efficient

•

High levels of Moesin contribute to defects in bipolar spindle assembly

•

Centrosome amplification generates aneuploidy and epithelial transformation

Moesin overexpression is a unique biomarker of adenomyosis

Adenomyosis is characterized by extension of endometrial glands and stromal cells into the myometrium. Here we proved that 'moesin' is a unique biomarker of adenomyosis. We selected two cases of adenomyosis that had been surgically resected and fixed with formalin. Proteins were extracted from the infiltrating adenomyosis lesions and normal endometrium by tissue microdissection. The extracted proteins were examined using a LC-MS/MS system and the expression profiles of each region were compared. Two hundred and sixty proteins were detected, among which 73 were expressed more in adenomyosis than in normal endometrium. Among these proteins, we focused on overexpression of moesin in adenomyosis. Expression of moesin estimated semiquantitatively using an immunohistochemistry score was higher in adenomyosis than in normal endometrium. In particular, moesin was significanly overexpressed in stromal cells of adenomyosis than in those of normal endometrium. Relative to normal endometrium, moesin was also overexpressed at the RNA level in 9 of 14 cases of adenomyosis and at the protein level in all 14 cases. We also detected activated (phosphorylated) moesin in adenomyosis lesions. The present findings suggest that moesin is characteristically overexpressed and activated in adenomyosis, and that moesin activation may be related to extension of adenomyosis in the myometrium.

MicroRNA-196a/-196b promote cell metastasis via negative regulation of radixin in human gastric cancer

MicroRNAs (miRNAs) play an important role to contribute carcinogenesis. The aim of the current study was to identify useful biomarkers from miRNAs. Differential miRNA profiles were analyzed using the miRNA qRT-PCR-based assay. Two of the most upregulated miRNAs were selected and validated. The miR-196a/-196b levels were significantly increased in gastric cancer (GC) tissues (n=109). Overexpression of miR-196a/-196b was significantly associated with tumor progression and poorer 5-year survival outcomes. Overexpression of miR-196a/-196b enhances GC cell migration and invasion. Further, radixin was identified as a target gene of miR-196a/-196b. Elevated miR-196a/-196b expression in GC cells led to reduced radixin protein levels and vice versa. Notably, an inverse correlation between miR-196a/-196b and radixin mRNA and protein expression was observed in GC tissues with in situ hybridization and immunohistochemistry analyses. Together, miR-196a/-196b inhibitory oligonucleotides or overexpression of the radixin may thus have therapeutic potential in suppressing GC metastasis.

Comparative proteome profiling of breast tumor cell lines by gel electrophoresis and mass spectrometry reveals an epithelial mesenchymal transition associated protein signature

The epithelial to mesenchymal transition (EMT) is a cellular program associated with the organ morphogenesis but also with the disease progression. EMT in the cancer field fuels neoplastic progression promoting the resistance to cell death, the resistance to chemotherapy and the acquisition of stem cell properties. Considering the crucial role of EMT in breast cancer metastasis, a better understanding of this process may provide new therapeutic options. Here, by using a proteomic approach we identified a set of proteins differentially expressed between an epithelial and a mesenchymal breast cancer cell line. The protein-protein network of these identified proteins was determined by an in silico analysis highlighting, in the EMT program, the role of proteins involved in cell adhesion, migration, and invasion, together with protein kinases involved in proliferation and survival, with many of these emerging as possible targets of novel biological agents. Finally, the pharmacological inhibition of some of these kinases was able to reverse the mesenchymal phenotype to an epithelial phenotype.

Quantitative proteomics of fractionated membrane and lumen exosome proteins from isogenic metastatic and nonmetastatic bladder cancer cells reveal differential expression of EMT factors

Cancer cells secrete soluble factors and various extracellular vesicles, including exosomes, into their tissue microenvironment. The secretion of exosomes is speculated to facilitate local invasion and metastatic spread. Here, we used an in vivo metastasis model of human bladder carcinoma cell line T24 without metastatic capacity and its two isogenic derivate cell lines SLT4 and FL3, which form metastases in the lungs and liver of mice, respectively. Cultivation in CLAD1000 bioreactors rather than conventional culture flasks resulted in a 13- to 16-fold increased exosome yield and facilitated quantitative proteomics of fractionated exosomes. Exosomes from T24, SLT4, and FL3 cells were partitioned into membrane and luminal fractions and changes in protein abundance related to the gain of metastatic capacity were identified by quantitative iTRAQ proteomics. We identified several proteins linked to epithelial-mesenchymal transition, including increased abundance of vimentin and hepatoma-derived growth factor in the membrane, and casein kinase II α and annexin A2 in the lumen of exosomes, respectively, from metastatic cells. The change in exosome protein abundance correlated little, although significant for FL3 versus T24, with changes in cellular mRNA expression. Our proteomic approach may help identification of proteins in the membrane and lumen of exosomes potentially involved in the metastatic process.

An in vivo RNAi screen identifies SALL1 as a tumor suppressor in human breast cancer with a role in CDH1 regulation

The gold standard for determining the tumorigenic potential of human cancer cells is a xenotransplantation into immunodeficient mice. Higher tumorigenicity of cells is associated with earlier tumor onset. Here, we used xenotransplantation to assess the tumorigenic potential of human breast cancer cells following RNA interference-mediated inhibition of over 5000 genes. We identify 16 candidate tumor suppressors, one of which is the zinc-finger transcription factor SALL1. Analyzing this particular molecule in more detail, we show that inhibition of SALL1 correlates with reduced levels of CDH1, an important contributor to epithelial-to-mesenchymal transition. Furthermore, SALL1 expression led to an increased migration and more than twice as many cells expressing a cancer stem cell signature. Also, SALL1 expression correlates with the survival of breast cancer patients. These findings cast new light on a gene that has previously been described to be relevant during embryogenesis, but not carcinogenesis.

A survey of immunohistochemical biomarkers for basal-like breast cancer against a gene expression profile gold standard

Gene expression profiling of breast cancer delineates a particularly aggressive subtype referred to as 'basal-like', which comprises ∼15% of all breast cancers, afflicts younger women and is refractory to endocrine and anti-HER2 therapies. Immunohistochemical surrogate definitions for basal-like breast cancer, such as the clinical ER/PR/HER2 triple-negative phenotype and models incorporating positive expression for CK5 (CK5/6) and/or EGFR are heavily cited. However, many additional biomarkers for basal-like breast cancer have been described in the literature. A parallel comparison of 46 proposed immunohistochemical biomarkers of basal-like breast cancer was performed against a gene expression profile gold standard on a tissue microarray containing 42 basal-like and 80 non-basal-like breast cancer cases. Ki67 and PPH3 were the most sensitive biomarkers (both 92%) positively expressed in the basal-like subtype, whereas CK14, IMP3 and NGFR were the most specific (100%). Among biomarkers surveyed, loss of INPP4B (a negative regulator of phosphatidylinositol signaling) was 61% sensitive and 99% specific with the highest odds ratio (OR) at 108, indicating the strongest association with basal-like breast cancer. Expression of nestin, a common marker of neural progenitor cells that is also associated with the triple-negative/basal-like phenotype and poor breast cancer prognosis, possessed the second highest OR at 29 among the 46 biomarkers surveyed, as well as 54% sensitivity and 96% specificity. As a positively expressed biomarker, nestin possesses technical advantages over INPP4B that make it a more ideal biomarker for identification of basal-like breast cancer. The comprehensive immunohistochemical biomarker survey presented in this study is a necessary step for determining an optimized surrogate immunopanel that best defines basal-like breast cancer in a practical and clinically accessible way.

MiR-200 can repress breast cancer metastasis through ZEB1-independent but moesin-dependent pathways

The microRNA-200 (miR-200) family has a critical role in regulating epithelial-mesenchymal transition and cancer cell invasion through inhibition of the E-cadherin transcriptional repressors ZEB1 and ZEB2. Recent studies have indicated that the miR-200 family may exert their effects at distinct stages in the metastatic process, with an overall effect of enhancing metastasis in a syngeneic mouse breast cancer model. We find in a xenograft orthotopic model of breast cancer metastasis that ectopic expression of members of the miR-200b/200c/429, but not the miR-141/200a, functional groups limits tumour cell invasion and metastasis. Despite modulation of the ZEB1-E-cadherin axis, restoration of ZEB1 in miR-200b-expressing cells was not able to alter metastatic potential suggesting that other targets contribute to this process. Instead, we found that miR-200b repressed several actin-associated genes, with the knockdown of the ezrin-radixin-moesin family member moesin alone phenocopying the repression of cell invasion by miR-200b. Moesin was verified to be directly targeted by miR-200b, and restoration of moesin in miR-200b-expressing cells was sufficient to alleviate metastatic repression. In breast cancer cell lines and patient samples, the expression of moesin significantly inversely correlated with miR-200 expression, and high levels of moesin were associated with poor relapse-free survival. These findings highlight the context-dependent effects of miR-200 in breast cancer metastasis and demonstrate the existence of a moesin-dependent pathway, distinct from the ZEB1-E-cadherin axis, through which miR-200 can regulate tumour cell plasticity and metastasis.

Presence in the pre-surgical fine-needle aspiration of potential thyroid biomarkers previously identified in the post-surgical one

Fine-needle aspiration biopsy (FNA) is usually applied to distinguish benign from malignant thyroid nodules. However, cytological analysis cannot always allow a proper diagnosis. We believe that the improvement of the diagnostic capability of pre-surgical FNA could avoid unnecessary thyroidectomy. In a previous study, we performed a proteome analysis to examine FNA collected after thyroidectomy. With the present study, we examined the applicability of these results on pre-surgical FNA. We collected pre-surgical FNA from 411 consecutive patients, and to obtain a correct comparison with our previous results, we processed only benign (n = 114), papillary classical variant (cPTC) (n = 34) and papillary tall cell variant (TcPTC) (n = 14) FNA. We evaluated levels of five proteins previously found up-regulated in thyroid cancer with respect to benign nodules. ELISA and western blot (WB) analysis were used to assay levels of L-lactate dehydrogenase B chain (LDHB), Ferritin heavy chain, Ferritin light chain, Annexin A1 (ANXA1), and Moesin in FNA. ELISA assays and WB analysis confirmed the increase of LDHB, Moesin, and ANXA1 in pre-surgical FNA of thyroid papillary cancer. Sensitivity and specificity of ANXA1 were respectively 87 and 94% for cPTC, 85 and 100% for TcPTC. In conclusion, a proteomic analysis of FNA from patients with thyroid nodules may help to distinguish benign versus malignant thyroid nodules. Moreover, ANXA1 appears to be an ideal candidate given the high sensitivity and specificity obtained from ROC curve analysis.

Expression of moesin and CD44 is associated with poor prognosis in gastric adenocarcinoma

AIMS

CD44 has been reported as a negative prognostic marker in gastric cancer. It interacts with moesin in epithelial-mesenchymal transition. To date, to our knowledge, there has been no clinical study dealing with the relationship between moesin and gastric adenocarcinoma. We analysed the expression of moesin and CD44 in gastric adenocarcinoma tissue, and correlations with clinicopathological factors.

METHODS AND RESULTS

A retrospective analysis was made of 430 patients who had undergone gastrectomy at the Korea University Guro Hospital between 2002 and 2005 for gastric adenocarcinoma. Using tissue microarray and immunohistochemical staining, moesin expression was observed in 192 (44.7%) cases; it was associated significantly with poorly differentiated histology, invasion depth, lymph node metastasis, lymphatic invasion and advanced pathological TNM stage. CD44 expression was not correlated with clinicopathological features or moesin expression. Moesin expression was a strong predictor of lymph node metastasis in logistic regression analysis. Both moesin expression and CD44 expression were associated significantly with poor overall survival in univariate analysis. Furthermore, in multivariate analysis, moesin and CD44 were independent markers of poor prognosis, along with pathological TNM stage and older patient age.

CONCLUSION

Moesin expression and CD44 expression might be useful markers of poor prognosis in gastric adenocarcinoma.

Molecular alterations in metaplastic breast carcinoma

Metaplastic carcinoma of the breast is a rare and heterogeneous subtype of breast carcinoma with a generally poor outcome, and few therapeutic options once disease recurs or progresses. Metaplastic carcinomas of the breast are usually of a larger size at diagnosis, with less frequent nodal metastasis compared with invasive ductal carcinoma no special type, and lack hormone and HER2 receptor expression. Recent research has revealed some potentially actionable genetic changes in a subset of these rare tumours. However, ongoing efforts to further characterise the genetic basis and the molecular alterations underlying the distinctive morphological and clinical characteristics of these tumours are needed in order to identify new targets for treatment. This review will describe the theories of pathogenesis of metaplastic breast carcinoma, and highlight genetic changes and potential therapeutic targets in this generally poor prognosis malignancy.

Establishment of a TGFβ-induced post-transcriptional EMT gene signature

A major challenge in the clinical management of human cancers is to accurately stratify patients according to risk and likelihood of a favorable response. Stratification is confounded by significant phenotypic heterogeneity in some tumor types, often without obvious criteria for subdivision. Despite intensive transcriptional array analyses, the identity and validation of cancer specific ‘signature genes’ remains elusive, partially because the transcriptome does not mirror the proteome. The simplification associated with transcriptomic profiling does not take into consideration changes in the relative expression among transcripts that arise due to post-transcriptional regulatory events. We have previously shown that TGFβ post-transcriptionally regulates epithelial-mesenchymal transition (EMT) by causing increased expression of two transcripts, Dab2 and ILEI, by modulating hnRNP E1 phosphorylation. Using a genome-wide combinatorial approach involving expression profiling and RIP-Chip analysis, we have identified a cohort of translationally regulated mRNAs that are induced during TGFβ-mediated EMT. Coordinated translational regulation by hnRNP E1 constitutes a post-transcriptional regulon inhibiting the expression of related EMT-facilitating genes, thus enabling the cell to rapidly and coordinately regulate multiple EMT-facilitating genes.