CPI-17 drives oncogenic Ras signaling in human melanomas via Ezrin-Radixin-Moesin family proteins

Identification of high-performing antibodies for Moesin for use in Western Blot, immunoprecipitation, and immunofluorescence

Moesin is a cytoskeletal adaptor protein, involved in the modification of the actin cytoskeleton, with relevance to Alzheimer's Disease. Well characterized anti-Moesin antibodies would benefit the scientific community. In this study, we have characterized ten Moesin commercial antibodies in Western Blot, immunoprecipitation, and immunofluorescence using a standardized experimental protocol based on comparing read-outs in knockout cell lines and isogenic parental controls. These studies are part of a larger, collaborative initiative seeking to address antibody reproducibility by characterizing commercially available antibodies for human proteins and publishing the results openly as a resource for the scientific community. While use of antibodies and protocols vary between laboratories, we encourage readers to use this report as a guide to select the most appropriate antibodies for their specific needs.

Human fetal cerebellar cell atlas informs medulloblastoma origin and oncogenesis

Medulloblastoma (MB) is the most common malignant childhood brain tumour1,2, yet the origin of the most aggressive subgroup-3 form remains elusive, impeding development of effective targeted treatments. Previous analyses of mouse cerebella3-5 have not fully defined the compositional heterogeneity of MBs. Here we undertook single-cell profiling of freshly isolated human fetal cerebella to establish a reference map delineating hierarchical cellular states in MBs. We identified a unique transitional cerebellar progenitor connecting neural stem cells to neuronal lineages in developing fetal cerebella. Intersectional analysis revealed that the transitional progenitors were enriched in aggressive MB subgroups, including group 3 and metastatic tumours. Single-cell multi-omics revealed underlying regulatory networks in the transitional progenitor populations, including transcriptional determinants HNRNPH1 and SOX11, which are correlated with clinical prognosis in group 3 MBs. Genomic and Hi-C profiling identified de novo long-range chromatin loops juxtaposing HNRNPH1/SOX11-targeted super-enhancers to cis-regulatory elements of MYC, an oncogenic driver for group 3 MBs. Targeting the transitional progenitor regulators inhibited MYC expression and MYC-driven group 3 MB growth. Our integrated single-cell atlases of human fetal cerebella and MBs show potential cell populations predisposed to transformation and regulatory circuitries underlying tumour cell states and oncogenesis, highlighting hitherto unrecognized transitional progenitor intermediates predictive of disease prognosis and potential therapeutic vulnerabilities.

Ezrin gone rogue in cancer progression and metastasis: An enticing therapeutic target

Cancer metastasis is the primary cause of morbidity and mortality in cancer as it remains the most complicated, devastating, and enigmatic aspect of cancer. Several decades of extensive research have identified several key players closely associated with metastasis. Among these players, cytoskeletal linker Ezrin (the founding member of the ERM (Ezrin-Radixin-Moesin) family) was identified as a critical promoter of metastasis in pediatric cancers in the early 21st century. Ezrin was discovered 40 years ago as a aminor component of intestinal epithelial microvillus core protein, which is enriched in actin-containing cell surface structures. It controls gastric acid secretion and plays diverse physiological roles including maintaining cell polarity, regulating cell adhesion, cell motility and morphogenesis. Extensive research for more than two decades evinces that Ezrin is frequently dysregulated in several human cancers. Overexpression, altered subcellular localization and/or aberrant activation of Ezrin are closely associated with higher metastatic incidence and patient mortality, thereby justifying Ezrin as a valuable prognostic biomarker in cancer. Ezrin plays multifaceted role in multiple aspects of cancer, with its significant contribution in the complex metastatic cascade, through reorganizing the cytoskeleton and deregulating various cellular signaling pathways. Current preclinical studies using genetic and/or pharmacological approaches reveal that inactivation of Ezrin results in significant inhibition of Ezrin-mediated tumor growth and metastasis as well as increase in the sensitivity of cancer cells to various chemotherapeutic drugs. In this review, we discuss the recent advances illuminating the molecular mechanisms responsible for Ezrin dysregulation in cancer and its pleiotropic role in cancer progression and metastasis. We also highlight its potential as a prognostic biomarker and therapeutic target in various cancers. More importantly, we put forward some potential questions, which we strongly believe, will stimulate both basic and translational research to better understand Ezrin-mediated malignancy, ultimately leading to the development of Ezrin-targeted cancer therapy for the betterment of human life.

Construction of a Six-Gene Prognostic Risk Model Related to Hypoxia and Angiogenesis for Cervical Cancer

Background: The prognosis of cervical cancer (CC) is poor and not accurately reflected by the primary tumor node metastasis staging system. Our study aimed to develop a novel survival-prediction model.

Methods: Hallmarks of CC were quantified using single-sample gene set enrichment analysis and univariate Cox proportional hazards analysis. We linked gene expression, hypoxia, and angiogenesis using weighted gene co-expression network analysis (WGCNA). Univariate and multivariate Cox regression was combined with the random forest algorithm to construct a prognostic model. We further evaluated the survival predictive power of the gene signature using Kaplan-Meier analysis and receiver operating characteristic (ROC) curves.

Results: Hypoxia and angiogenesis were the leading risk factors contributing to poor overall survival (OS) of patients with CC. We identified 109 candidate genes using WGCNA and univariate Cox regression. Our established prognostic model contained six genes (MOCSI, PPP1R14A, ESM1, DES, ITGA5, and SERPINF1). Kaplan-Meier analysis indicated that high-risk patients had worse OS (hazard ratio = 4.63, p < 0.001). Our model had high predictive power according to the ROC curve. The C-index indicated that the risk score was a better predictor of survival than other clinicopathological variables. Additionally, univariate and multivariate Cox regressions indicated that the risk score was the only independent risk factor for poor OS. The risk score was also an independent predictor in the validation set (GSE52903). Bivariate survival prediction suggested that patients exhibited poor prognosis if they had high z-scores for hypoxia or angiogenesis and high risk scores.

Conclusions: We established a six-gene survival prediction model associated with hypoxia and angiogenesis. This novel model accurately predicts survival and also provides potential therapeutic targets.

Prognostic and Immunological Role of PPP1R14A as a Pan-Cancer Analysis Candidate

Despite emerging evidence revealing the remarkable roles of protein phosphatase 1 regulatory inhibitor subunit 14A (PPP1R14A) in cancer tumorigenesis and progression, no pan-cancer analysis is available. A comprehensive investigation of the potential carcinogenic mechanism of PPP1R14A across 33 tumors using bioinformatic techniques is reported for the first time. PPP1R14A is downregulated in major malignancies, and there is a significant correlation between the PPP1R14A expression and the prognosis of patients. The high expression of PPP1R14A in most cases was associated with poor overall survival (OS), disease-specific survival (DSS), and progress-free interval (PFI) across patients with various malignant tumors, including adrenocortical carcinoma (ACC) and bladder urothelial carcinoma (BLCA), indicated through pan-cancer survival analysis. Receiver operating characteristic (ROC) analysis subsequently exhibited that the molecule has high reference significance in diagnosing a variety of cancers. The frequency of PPP1R14A genetic changes including genetic mutations and copy number alterations (CNAs) in uterine carcinosarcoma reached 16.07%, and these alterations brought misfortune to the survival and prognosis of cancer patients. In addition, methylation within the promoter region of PPP1R14A DNA was enhanced in a majority of cancers. Downregulated phosphorylation levels of phosphorylation sites including S26, T38, and others in most cases took place in several tumors, such as breast cancer and colon cancer. PPP1R14A remarkably correlated with the levels of infiltrating cells and immune checkpoint genes. Our research on the carcinogenic effect of PPP1R14A in different tumors is comprehensively summarized and analyzed and provides a theoretical basis for future therapeutic and immunotherapy strategies.

Novel role of prostate cancer risk variant rs7247241 on PPP1R14A isoform transition through allelic TF binding and CpG methylation

Although previous studies identified numerous single nucleotide polymorphisms (SNPs) and their target genes predisposed to prostate cancer (PrCa) risks, SNP-related splicing associations are rarely reported. In this study, we applied distance-based sQTL analysis (sQTLseekeR) using RNA-seq and SNP genotype data from benign prostate tissue (n = 467), and identified significant associations in 3344 SNP-transcript pairs (P ≤ 0.05) at PrCa risk loci. We characterized a common SNP (rs7247241) and its target gene (PPP1R14A) located in chr19q13, a sQTL with risk allele T associated with upregulation of long isoform (P = 9.99E-7). We confirmed the associations in both TCGA (P = 2.42E-24) and GTEX prostate cohorts (P = 9.08E-78). To functionally characterize this SNP, we performed chromatin Immunoprecipitation qPCR and confirmed stronger CTCF and PLAGL2 binding in rs7247241 C than T allele. We found that CTCF binding enrichment was negatively associated with methylation level at the SNP site in human cell lines (r = -0.58). Bisulfite sequencing showed consistent association of rs7247241-T allele with nearby sequence CpG hypermethylation in prostate cell lines and tissues. Importantly, the methylation level at CpG sites nearest to the CTCF binding and first exon splice-in (ψ) of PPP1R14A were significantly associated with aggressive phenotype in the TCGA PrCa cohort. Meanwhile, the long isoform of the gene also promoted cell proliferation. Taken together, with the most updated gene annotations, we reported a set of sQTL associated with multiple traits related to human prostate diseases, and revealed a unique role of PrCa risk SNP rs7247241 on PPP1R14A isoform transition.

The Epithelial and Stromal Immune Microenvironment in Gastric Cancer: A Comprehensive Analysis Reveals Prognostic Factors with Digital Cytometry

Gastric cancer (GC) is the third leading cause of cancer-related deaths worldwide. Tumor heterogeneity continues to confound researchers' understanding of tumor growth and the development of an effective therapy. Digital cytometry allows interpretation of heterogeneous bulk tissue transcriptomes at the cellular level. We built a novel signature matrix to dissect epithelium and stroma signals using a scRNA-seq data set (GSE134520) for GC and then applied cell mixture deconvolution to estimate diverse epithelial, stromal, and immune cell proportions from bulk transcriptome data in four independent GC cohorts (GSE62254, GSE15459, GSE84437, and TCGA-STAD) from the GEO and TCGA databases. Robust computational methods were applied to identify strong prognostic factors for GC. We identified an EMEC population whose proportions were significantly higher in patients with stage I cancer than other stages, and it was predominantly present in tumor samples but not typically found in normal samples. We found that the ratio of EMECs to stromal cells and the ratio of adaptive T cells to monocytes were the most significant prognostic factors within the non-immune and immune factors, respectively. The STEM score, which unifies these two prognostic factors, was an independent prognostic factor of overall survival (HR = 0.92, 95% CI = 0.89-0.94, p=2.05×10-9). The entire GC cohort was stratified into three risk groups (high-, moderate-, and low-risk), which yielded incremental survival times (p<0.0001). For stage III disease, patients in the moderate- and low-risk groups experienced better survival benefits from radiation therapy ((HR = 0.16, 95% CI = 0.06-0.4, p<0.0001), whereas those in the high-risk group did not (HR = 0.49, 95% CI = 0.14-1.72, p=0.25). We concluded that the STEM score is a promising prognostic factor for gastric cancer.

Integrated single-cell and bulk RNA sequencing analysis identifies a cancer associated fibroblast-related signature for predicting prognosis and therapeutic responses in colorectal cancer

Background

Cancer-associated fibroblasts (CAFs) contribute notably to colorectal cancer (CRC) tumorigenesis, stiffness, angiogenesis, immunosuppression and metastasis, and could serve as a promising therapeutic target. Our purpose was to construct CAF-related prognostic signature for CRC.

Methods

We performed bioinformatics analysis on single-cell transcriptome data derived from Gene Expression Omnibus (GEO) and identified 208 differentially expressed cell markers from fibroblasts cluster. Bulk gene expression data of CRC was obtained from The Cancer Genome Atlas (TCGA) and GEO databases. Univariate Cox regression and least absolute shrinkage operator (LASSO) analyses were performed on TCGA training cohort (n = 308) for model construction, and was validated in TCGA validation (n = 133), TCGA total (n = 441), GSE39582 (n = 470) and GSE17536 (n = 177) datasets. Microenvironment Cell Populations-counter (MCP-counter) and Estimate the Proportion of Immune and Cancer cells (EPIC) methods were applied to evaluated CAFs infiltrations from bulk gene expression data. Real-time polymerase chain reaction (qPCR) was performed in tissue microarrays containing 80 colon cancer samples to further validate the prognostic value of the CAF model. pRRophetic and Tumor Immune Dysfunction and Exclusion (TIDE) algorithms were utilized to predict chemosensitivity and immunotherapy response. Human Protein Atlas (HPA) databases and immunohistochemistry were used to evaluate the protein expressions.

Results

A nine-gene prognostic CAF-related signature was established in training cohort. Kaplan–Meier survival analyses revealed patients with higher CAF risk scores were correlated with adverse prognosis in each cohort. MCP-counter and EPIC results consistently revealed CAFs infiltrations were significantly higher in high CAF risk group. Patients with higher CAF risk scores were more prone to not respond to immunotherapy, but were more sensitive to several conventional chemotherapeutics, suggesting a potential strategy of combining chemotherapy with anti-CAF therapy to improve the efficacy of current T-cell based immunotherapies. Univariate and multivariate Cox regression analyses verified the CAF model was as an independent prognostic indicator in predicting overall survival, and a CAF-based nomogram was then built for clinical utility in predicting prognosis of CRC.

Conclusion

To conclude, the CAF-related signature could serve as a robust prognostic indicator in CRC, which provides novel genomics evidence for anti-CAF immunotherapeutic strategies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02252-9.

Potential Molecular Biomarkers of Vestibular Schwannoma Growth: Progress and Prospects

Vestibular schwannomas (VSs, also known as acoustic neuromas) are relatively rare benign brain tumors stem from the Schwann cells of the eighth cranial nerve. Tumor growth is the paramount factor for neurosurgeons to decide whether to choose aggressive treatment approach or careful follow-up with regular magnetic resonance imaging (MRI), as surgery and radiation can introduce significant trauma and affect neurological function, while tumor enlargement during long-term follow-up will compress the adjacent nerves and tissues, causing progressive hearing loss, tinnitus and vertigo. Recently, with the deepening research of VS biology, some proteins that regulate merlin conformation changes, inflammatory cytokines, miRNAs, tissue proteins and cerebrospinal fluid (CSF) components have been proposed to be closely related to tumor volume increase. In this review, we discuss advances in the study of biomarkers that associated with VS growth, providing a reference for exploring the growth course of VS and determining the optimal treatment strategy for each patient.

The development of multi-kinase inhibitors as pancreatic cancer therapeutics

Pancreatic cancer is an almost incurable malignancy whose incidence has increased over the past 30 years. Instead of pursuing the development of modalities utilizing 'traditional' cytotoxic chemotherapeutic agents, we have explored the possibilities of developing novel multi-kinase inhibitor drug combinations to kill this tumor type. Several approaches using the multi-kinase inhibitors sorafenib, regorafenib, and neratinib have been safely translated from the bench to the bedside, with objective anti-tumor responses. This review will discuss our prior preclinical and clinical studies and discuss future clinical opportunities in this disease.

Osimertinib-resistant NSCLC cells activate ERBB2 and YAP/TAZ and are killed by neratinib

We performed additional mechanistic analyses to redefine neratinib biology and determined the mechanisms by which the multi-kinase inhibitor neratinib interacted with the thymidylate synthase inhibitor pemetrexed to kill NSCLC cells expressing either mutant KRAS (G12S; Q61H; G12A; G12C) or mutant NRAS (Q61K) or mutant ERBB1 (L858R; L858R T790M; exon 19 deletion). Neratinib rapidly reduced KRASG12V and RAC1G12V nanoclustering which was followed by KRASG12V, but not RAC1G12V, being extensively mislocalized away from the plasma membrane. This correlated with reduced levels of, and reorganized membrane localization of phosphatidylserine and cholesterol. Reduced nanoclustering was not associated with inactivation of ERBB1, Merlin or Ezrin. The drug combination killed cells expressing mutant KRAS, NRAS or mutant ERBB1 proteins. Afatinib or osimertinib resistant cells were killed with a similar efficacy to non-resistant cells. Compared to osimertinib-resistant cells, sensitive cells had less ERBB2 Y1248 phosphorylation. In osimertinib resistant H1975 cells, the drug combination was less capable of inactivating AKT, mTOR, STAT3, STAT5, ERK1/2 whereas it gained the ability to inactivate ERBB3. In resistant H1650 cells, the drug combination was less capable of inactivating JAK2 and STAT5. Sensitive cells exhibited elevated basal phosphorylation of YAP and TAZ. In resistant cells, portions of YAP and TAZ were localized in the nucleus. [Neratinib + pemetrexed] increased phosphorylation of YAP and TAZ, caused their nuclear exit, and enhanced ERBB2 degradation. Thus, neratinib targets an unidentified protein whose functional inhibition directly results in RAS inactivation and tumor cell killing. Our data prove that, albeit indirectly, oncogenic RAS proteins are druggable by neratinib.

Moesin as a prognostic indicator of lung adenocarcinoma improves prognosis by enhancing immune lymphocyte infiltration

BACKGROUND

Ezrin-radixin-moesin (ERM) have been explored in many cancer processes. Moesin, as its component, has also been found to play an important role in the prognosis of cancer patients, tumor metastasis, drug resistance, and others. Especially in regulating the immunity, but most results came from direct studies on immune cells, there is no clear conclusion on whether moesin has similar effects in tumor cells. And moesin has certain research results in many cancers in other aspects, but there are few about moesin in lung adenocarcinoma (LUAD).

METHODS

We detect the expression of moesin in 82 LUAD and matched normal tissue samples by immunohistochemistry. Besides, for the pathological feature, we did a detailed statistical analysis. And with the help of various databases, we have done in-depth exploration of moesin's ability to enhance the extent of immune lymphocyte infiltration.

RESULTS

Moesin is a poor expression in lung cancer tissues than the corresponding normal samples. And this phenomenon had a strongly associated with the prognosis and TNM stage of these LUAD patients. Moesin can enhance the infiltration of multiple immune lymphocytes in lung cancer. And this may be related to the interaction between moesin and various inflammatory molecules.

CONCLUSIONS

Moesin is a newly index for the prognosis of LUAD and improves the prognosis of LUAD patients by regulating a variety of inflammation-related molecules to enhance immune lymphocytes infiltration.

Ezrin Mediates Invasion and Metastasis in Tumorigenesis: A Review

Ezrin, as encoded by the EZR gene, is a member of the Ezrin/Radixin/Moesin (ERM) family. The ERM family includes three highly related actin filament binding proteins, Ezrin, Radixin, and Moesin. These three members share similar structural properties containing an N-terminal domain named FERM, a central helical linker region, and a C-terminal domain that mediates the interaction with F-actin. Ezrin protein is highly regulated through the conformational change between a closed, inactivate form and an open, active form. As a membrane-cytoskeleton linker protein, Ezrin facilitates numerous signal transductions in tumorigenesis and mediates diverse essential functions through interactions with a variety of growth factor receptors and adhesion molecules. Emerging evidence has demonstrated that Ezrin is an oncogene protein, as high levels of Ezrin are associated with metastatic behavior in various types of cancer. The diverse functions attributed to Ezrin and the understanding of how Ezrin drives the deadly process of metastasis are complex and often controversial. Here by reviewing recent findings across a wide spectrum of cancer types we will highlight the structures, protein interactions and oncogenic roles of Ezrin as well as the emerging therapeutic agents targeting Ezrin. This review provides a comprehensive framework to guide future studies of Ezrin and other ERM proteins in basic and clinical studies.

CPI-17 Overexpression and Its Correlation With the NF2 Mutation Spectrum in Sporadic Vestibular Schwannomas

HYPOTHESIS

We hypothesized that CPI-17 expression and NF2 mutations are correlated with merlin phosphorylation in the etiology of sporadic vestibular schwannoma (VS).

BACKGROUND

NF2 gene mutations have been identified in the majority of sporadic and NF2-associated schwannomas and NF2 gene mutations have been shown to result in merlin protein phosphorylation. CPI-17 can drive Ras activity and promote tumorigenic transformation by inhibiting the tumor suppressor merlin. The aim of this study was to determine the correlation between CPI-17 overexpression and the NF2 mutation spectrum in sporadic VS.

METHODS

In this study, we measured CPI-17 expression and identified NF2 gene alterations in a series of sporadic VS samples. Freshly frozen tumor and matched peripheral blood leukocytes from 44 individuals with sporadic VS were analyzed using next-generation sequencing and Sanger sequencing. Western blotting was used to determine the level of merlin phosphorylation, and immunohistochemistry and Western blotting were used to measure CPI-17 expression in the sporadic VS samples. CCK-8 and wound-healing assays were used to determine the influence of CPI-17 overexpression on cell proliferation.

RESULTS

NF2 mutations were identified in 79.5% of sporadic vestibular schwannomas, with all mutations being exclusively somatic. IHC and WB showed the expression of CPI-17 is upregulated in the sporadic VS. NF2 mutation and CPI-17 are positively correlated with merlin phosphorylation. CPI-17 overexpression induces the proliferation of HEI193 cells.

CONCLUSION

NF2 mutations and CPI-17 expression together induce merlin phosphorylation, which is correlated with the tumorigenesis of sporadic VSs.

Development and validation of a hypoxia-immune-based microenvironment gene signature for risk stratification in gastric cancer

Background

Increasing evidences have found that the clinical importance of the interaction between hypoxia and immune status in gastric cancer microenvironment. However, reliable prognostic signatures based on combination of hypoxia and immune status have not been well-established. This study aimed to develop a hypoxia-immune-based gene signature for risk stratification in gastric cancer.

Methods

Hypoxia and immune status was estimated with transcriptomic profiles for a discovery cohort from GEO database using the t-SNE and ESTIMATE algorithms, respectively. The Cox regression model with the LASSO method was applied to identify prognostic genes and to develop a hypoxia-immune-based gene signature. The TCGA cohort and two independent cohorts from GEO database were used for external validation.

Results

Low hypoxia status (p < 0.001) and high immune status (p = 0.005) were identified as favorable factors for patients’ overall survival. By using the LASSO model, four genes, including CXCR6, PPP1R14A and TAGLN, were identified to construct a gene signature for risk stratification. In the discovery cohort (n = 357), patients with low risk yielded better outcomes than those with high risk regarding overall survival across and within TNM stage subgroups. Multivariate analysis identified the hypoxia-immune-based gene signature as an independent prognostic factor (p < 0.001). A nomogram integrating the gene signature and known risk factors yielded better performance and net benefits in calibration and decision curve analyses. Similar results were validated in the TCGA (n = 321) and two independent GEO (n = 300 and n = 136, respectively) cohorts.

Conclusions

The hypoxia-immune-based gene signature represents a promising tool for risk stratification tool in gastric cancer. It might serve as a prognostic classifier for clinical decision-making regarding individualized prognostication and treatment, and follow-up scheduling.

Mechanism of Dyslipidemia in Obesity-Unique Regulation of Ileal Villus Cell Brush Border Membrane Sodium-Bile Acid Cotransport

In obesity, increased absorption of dietary fat contributes to altered lipid homeostasis. In turn, dyslipidemia of obesity leads to many of the complications of obesity. Bile acids are necessary for the absorption of dietary fat. In the mammalian intestine, apical sodium-dependent bile acid cotransporter (ASBT; SLC10A2) is exclusively responsible for the reabsorption of bile acids in the terminal ileum. In rat and mice models of obesity and importantly in obese humans, ASBT was increased in ileal villus cells. The mechanism of stimulation of ASBT was secondary to an increase in ASBT expression in villus cell brush border membrane. The stimulation of ASBT was not secondary to the altered Na-extruding capacity of villus cells during obesity. Further, increased Farnesoid X receptor (FXR) expression in villus cells during obesity likely mediated the increase in ASBT. Moreover, enhanced FXR expression increased the expression of bile-acid-associated proteins (IBABP and OSTα) that are responsible for handling bile acids absorbed via ASBT in villus cells during obesity. Thus, this study demonstrated that in an epidemic condition, obesity, the dyslipidemia that leads to many of the complications of the condition, may, at least in part, be due to deregulation of intestinal bile acid absorption.

Kallikrein-related peptidases 4, 5, 6 and 7 regulate tumour-associated factors in serous ovarian cancer

BACKGROUND

Tissue kallikrein-related peptidases 4, 5, 6 and 7 (KLK4-7) strongly increase the malignancy of ovarian cancer cells. Deciphering their downstream effectors, we aimed at finding new potential prognostic biomarkers and treatment targets for ovarian cancer patients. KLK4-7-transfected (OV-KLK4-7) and vector-control OV-MZ-6 (OV-VC) ovarian cancer cells were established to select differentially regulated factors.

METHODS

With three independent approaches, PCR arrays, genome-wide microarray and proteome analyses, we identified 10 candidates (MSN, KRT19, COL5A2, COL1A2, BMP5, F10, KRT7, JUNB, BMP4, MMP1). To determine differential protein expression, we performed western blot analyses, immunofluorescence and immunohistochemistry for four candidates (MSN, KRT19, KRT7, JUNB) in cells, tumour xenograft and patient-derived tissues.

RESULTS

We demonstrated that KLK4-7 clearly regulates expression of MSN, KRT19, KRT7 and JUNB at the mRNA and protein levels in ovarian cancer cells and tissues. Protein expression of the top-upregulated effectors, MSN and KRT19, was investigated by immunohistochemistry in patients afflicted with serous ovarian cancer and related to KLK4-7 immunoexpression. Significant positive associations were found for KRT19/KLK4, KRT19/KLK5 and MSN/KLK7.

CONCLUSION

These findings imply that KLK4-7 exert key modulatory effects on other cancer-related genes and proteins in ovarian cancer. These downstream effectors of KLK4-7, MSN and KRT19 may represent important therapeutic targets in serous ovarian cancer.

Myosin phosphatase: Unexpected functions of a long-known enzyme

Myosin phosphatase (MP) holoenzyme is a Ser/Thr specific enzyme, which is the member of protein phosphatase type 1 (PP1) family and composed of a PP1 catalytic subunit (PP1c/PPP1CB) and a myosin phosphatase targeting subunit (MYPT1/PPP1R12A). PP1c is required for the catalytic activity of the holoenzyme, while MYPT1 regulates MP through targeting the holoenzyme to its substrates. Above the well-characterized function of MP, as the major regulator of smooth muscle contractility mediating the dephosphorylation of 20 kDa myosin light chain, accumulating data support its role in other, non-contractile functions. In this review, we summarize the scaffold function of MP holoenzyme and its roles in processes such as cell cycle, development, gene expression regulation and neurotransmitter release. In particular, we highlight novel interacting proteins of MYPT1 and pathophysiological functions of MP relevant to tumorigenesis, insulin resistance and neurodegenerative disorders. This article is part of a Special Issue entitled: Protein Phosphatases as Critical Regulators for Cellular Homeostasis edited by Prof. Peter Ruvolo and Dr. Veerle Janssens.

Diversity and plasticity in signaling pathways that regulate smooth muscle responsiveness: Paradigms and paradoxes for the myosin phosphatase, the master regulator of smooth muscle contraction

A hallmark of smooth muscle cells is their ability to adapt their functions to meet temporal and chronic fluctuations in their demands. These functions include force development and growth. Understanding the mechanisms underlying the functional plasticity of smooth muscles, the major constituent of organ walls, is fundamental to elucidating pathophysiological rationales of failures of organ functions. Also, the knowledge is expected to facilitate devising innovative strategies that more precisely monitor and normalize organ functions by targeting individual smooth muscles. Evidence has established a current paradigm that the myosin light chain phosphatase (MLCP) is a master regulator of smooth muscle responsiveness to stimuli. Cellular MLCP activity is negatively and positively regulated in response to G-protein activation and cAMP/cGMP production, respectively, through the MYPT1 regulatory subunit and an endogenous inhibitor protein named CPI-17. In this article we review the outcomes from two decade of research on the CPI-17 signaling and discuss emerging paradoxes in the view of signaling pathways regulating smooth muscle functions through MLCP.

Detecting the location and significance of Ezrin protein expression in hepatocellular carcinoma

To explore the characteristics of localization and prognostic implication of Ezrin expression in HCC, 92 cases of HCC meeting strict follow-up criteria were selected for immunohistochemical staining of Ezrin protein. Correlations between Ezrin expression and clinicopathological features of HCC were evaluated using Chi-square tests, survival rates were calculated using the Kaplan-Meier method, and the relationship between prognostic factors and patient overallsurvival was analyzed using Cox proportional hazard analysis. In results, Ezrin protein was mainly expressed in the inner side of the cell membrane of the adjacent non tumor tissues, and diffusely expressed in cytoplasm of HCC tissues. There was an obviously difference between the benign and malignant tissues about the location of Ezrin expression. Ezrin strong-expression rates were significantly higher in HCC samples compared with the adjacent non tumor tissues (P<0.05). The Ezrin strong-expression rate was closely related with the differentiation (P<0.01), AJCC stage and metastasis of HCC (P<0.05, respectively). Therefore, the sub-cellular localization of Ezrin protein in the liver cells will be changed in the process of the transformation from the benign to malignant, and Ezrin plays an important role in the progression of HCC.

Dishevelled2 promotes apoptosis and inhibits inflammatory cytokine secretion in rheumatoid arthritis fibroblast-like synoviocytes through crosstalk with the NF-κB pathway

Dishevelled (Dvl) not only links the canonical Wnt and non-canonical Wnt pathways but can also crosstalk with other pathways. As there is no systematic study to date on Dvl in rheumatoid arthritis (RA), we explored the impact of Dvl2 on proliferation and inflammatory cytokine secretion in RA fibroblast-like synoviocytes (FLSs). Expression of Dvl2 in RA synovial tissue and RA-FLSs was measured. Dvl2 was overexpressed in collagen-induced arthritis rats and human RA-FLSs,. the apoptosis and secretion of inflammatory cytokines were observed. Genetic changes and corresponding mechanisms caused by overexpressing Dvl2 in RA-FLSs were assessed. Dvl2 was found to be overexpressed in RA synovial tissue and RA-FLSs. Overexpression of Dvl2 increased apoptosis and inhibited inflammatory cytokine secretion by RA-FLSs in vivo and in vitro, and Dvl2 inhibited expression of anti-apoptotic and inflammatory genes. One possible mechanism is that Dvl2 decreases the nuclear translocation of P65 and inhibits its ability to bind to the promoters of NF-κB target genes. Our findings reveal an underappreciated role of Dvl2 in regulating inflammation and RA-FLS apoptosis and provide insight into crosstalk between the Wnt and nuclear factor-κB (NF-κB) pathways.

miR-19b promotes breast cancer metastasis through targeting MYLIP and its related cell adhesion molecules

miR-19b is a key molecule for cancer development, however its crucial roles in breast cancer metastasis are rarely studied right now. In this study, using several bioinformatics databases to predict the downstream targets for miR-19b, we verified that a novel target gene, myosin regulatory light chain interacting protein (MYLIP), could be directly down-regulated by miR-19b through its 3′-UTR region. MYLIP belongs to the cytoskeletal protein clusters and is involved in the regulation of cell movement and migration. We further explored that miR-19b was highly expressed and negatively correlated with MYLIP expression in breast cancer patient samples from the TCGA database. And the over-expression of miR-19b or inhibition of MYLIP facilitated the migration and metastasis of breast cancer cells, through conducting the wound healing assay and transwell invasion assay. Additionally, miR-19b could obviously promote breast tumor growth in mouse models and affect the expressions of cell adhesion molecules (including E-Cadherin, ICAM-1 and Integrin β1) by down-regulating E-Cadherin expression and up-regulating ICAM-1 and Integrin β1 expressions in vitro and in vivo. Meanwhile, miR-19b effectively activated the Integrin β downstream signaling pathways (such as the Ras-MAPK pathway and the PI3K-AKT pathway) and elevated the expression levels of essential genes in these two pathways. Taken together, these findings comprehensively illustrate the regulatory mechanisms ofmiR-19b in breast cancer metastasis, and provide us new insights for exploring MYLIP and its related cell adhesion molecules as promising therapeutic targets to interfere breast cancer development.