[Corrigendum] The tetraspanin CD151‑ARSA mutant inhibits angiogenesis via the YRSL sequence

Subsequently to the publication of the above paper, an interested reader drew to the authors' attention that, in Fig. 4A on p. 839, the 'CD151/24 h' and 'CD151‑ARSA/48 h' panels appeared to contain overlapping sections of data, such that they were potentially derived from the same original source, where these panels were intended to show the results from differently performed experiments. The authors have re‑examined their original data, and realize that the 'CD151‑ARSA/48 h' panel was inadvertently placed incorrectly in the figure. The revised version of Fig. 4, now containing the correct data for the 'CD151‑ARSA/48 h' experiment in Fig. 4A, is shown below. Note that this error did not adversely affect either the results or the overall conclusions reported in this study. All the authors agree with the publication of this corrigendum, and are grateful to the Editor of Molecular Medicine Reports for allowing them the opportunity to publish this. They also wish to apologize to the readership of the Journal for any inconvenience caused. [Molecular Medicine Reports 7: 836‑842, 2013; DOI: 10.3892/mmr.2012.1250].

LncSUMO1P3 exacerbates malignant behaviors of esophageal squamous cell carcinoma cells via miR-486-5p/PHF8/CD151

Background

Esophageal squamous cell carcinoma (ESCC) is a malignancy usually associated with smoking or alcohol consumption. The involvement of long noncoding RNAs (lncRNAs) in the regulation of tumor development and metastasis through molecular mechanisms has been unveiled by accumulating evidence. However, the function of lncRNA SUMO1 Pseudogene 3 (lncSUMO1P3) essential to ESCC development remains obscure.

Methods

Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) and Western blot (WB) analysis were done to measure RNA and protein levels. Functional assays were carried out to examine the changes in ESCC cell phenotype. Supported by bioinformatics analysis, mechanism assays were done for assessment of putative interactions among different genes.

Results

LlncSUMO1P3 was aberrantly up-regulated in ESCC cell lines, and lncSUMO1P3 deficiency could hamper cell proliferation, migration and invasion as well as epithelial-mesenchymaltransition (EMT) in ESCC while lncSUMO1P3 overexpression led to the opposite consequences. LncSUMO1P3 could competitively bind to microRNA-486-5p (miR-486-5p) or PHD finger protein 8 (PHF8) to modulate CD151 expression. CD151 was also verified to regulate ESCC cell biological behaviors.

Conclusion

Our study revealed that lncSUMO1P3, up-regulated in ESCC cells, could sponge miR-486-5p and recruit PHF8 to up-regulate CD151, thus influencing the malignant behaviors of ESCC cells.

Role of Hemidesmosomes in Oral Carcinogenesis: A Systematic Review

BACKGROUND

Oral cancers have limited diagnostic tools to aid clinical management. Current evidence indicates that alterations in hemidesmosomes, the adhesion complexes primarily involved in epithelial attachment to the basement membrane, are correlated to cancer phenotype for multiple cancers. This systematic review aimed to assess the experimental evidence for hemidesmosomal alterations, specifically in relation to oral potentially malignant disorders and oral squamous cell carcinomas.

METHODS

We conducted a systemic review to summarise the available literature on hemidesmosomal components and their role in oral pre-cancer and cancer. Relevant studies were retrieved from a comprehensive search of Scopus, Ovid MEDLINE, Ovid Embase and Web of Science.

RESULTS

26 articles met the inclusion criteria, of which 19 were in vitro studies, 4 in vivo studies, 1 in vitro and in vivo study, and 2 in vitro and cohort studies. Among them, 15 studies discussed individual alpha-6 and/or beta-4 subunits, 12 studies discussed the alpha-6 beta-4 heterodimers, 6 studies discussed the entire hemidesmosome complex, 5 studies discussed bullous pemphigoid-180, 3 studies discussed plectin, 3 studies discussed bullous pemphigoid antigen-1 and 1 study discussed tetraspanin.

CONCLUSION

Heterogeneity in cell type, experimental models, and methods were observed. Alterations in hemidesmosomal components were shown to contribute to oral pre-cancer and cancer. We conclude that there is sufficient evidence for hemidesmosomes and their components to be potential biomarkers for evaluating oral carcinogenesis.

Exploring the role of CD151 in the tumor immune microenvironment: Therapeutic and clinical perspectives

CD151 is a transmembrane protein implicated in tumor progression and has been shown to regulate various cellular and molecular mechanisms contributing to malignancy. More recently, the role of CD151 in the tumor immune microenvironment (TIME) has gained attention as a potential target for cancer therapy. This review aims to explore the role of CD151 in the TIME, focusing on the therapeutic and clinical perspectives. The role of CD151 in regulating the interactions between tumor cells and the immune system will be discussed, along with the current understanding of the molecular mechanisms underlying these interactions. The current state of the development of CD151-targeted therapies and the potential clinical applications of these therapies will also be reviewed. This review provides an overview of the current knowledge on the role of CD151 in the TIME and highlights the potential of CD151 as a therapeutic target for cancer treatment.

Proteomic profiling and ROC analysis identify CD151 and ELAVL1 as potential therapy response markers for the antiviral drug in resistant TNBC

Triple-negative breast cancer is high heterogeneous, aggressive, and metastatic with poor prognosis. Despite of advances in targeted therapies, TNBC has been reported to cause high morbidity and mortality. A rare subpopulation within the tumor microenvironment organized into a hierarchy of cancer stem cells is responsible for therapy resistance and tumor recurrence. Repurposing of antiviral drugs for cancer treatment is gaining momentum due to reduced cost, labour, and research time, but limited due to lack of prognostic, and predictive markers. The present study investigates proteomic profiling and ROC analysis to identify CD151 and ELAVL1 as potential therapy response markers for the antiviral drug 2-thio-6-azauridine (TAU) in resistant TNBC. The stemness of MDA-MB 231 and MDA-MD 468 adherent cells was enriched by culturing them under non-adherent and non-differentiation conditions. Then, CD151⁺ subpopulation was isolated and characterized for the enrichment of stemness. This study found that CD151 has overexpressed in stemness enriched subpopulations, and also showed CD44 high and CD24 low expression along with stem cell-related transcription factors octamer-binding transcription factor 4 (OCT4) and Sex determining Y-box 2 (SOX2). This study also found that TAU induced significant cytotoxicity and genotoxicity in the CD151⁺TNBC subpopulation and inhibited their proliferation by inducing DNA damage, cell cycle arrest at the G₂M phase, and apoptosis. Further, a proteomic profiling study showed that the expression of CD151 along with ELAVL1, an RNA-binding protein, was significantly reduced with TAU treatment. KM plotter showed correlation of CD151 and ELAVL1 gene expression with a poor prognosis of TNBC. ROC analysis predicted and validated CD151 and ELAVL1 as best therapy response marker for TAU in TNBC. These findings provide new insight into repurposing antiviral drug TAU for treatment of metastatic and drug resistant TNBC.

Comparative Analysis of Tumor-Associated microRNAs and Tetraspanines from Exosomes of Plasma and Ascitic Fluids of Ovarian Cancer Patients

Ovarian cancer (OC) is one of the most common and fatal types of gynecological cancer. In the early phase of OC detection, the current treatment and diagnostic methods are not efficient and sensitive enough. Therefore, it is crucial to explore the mechanisms of OC metastasis and discover valuable factors for early diagnosis of female cancers and novel therapeutic strategies for metastasis. Exosomes are known to be involved in the development, migration, and invasion of cancer cells, and their cargo could be useful for the non-invasive biopsy development. CD151- and Tspan8-positive exosomes are known to support the degradation of the extracellular matrix, and are involved in stroma remodeling, angiogenesis and cell motility, as well as the association of miR-24 and miR-101 with these processes. The objective of this study was to explore the relationship of these components of exosomal cargo, in patients with OC, to clarify the clinical significance of these markers in liquid biopsies. The levels of tetraspanins Tspan8+ and CD151+ exosomes were significantly higher in plasma exosomes of OC patients compared with healthy females (HFs). The relative levels of miR-24 and miR-101 in plasma exosomes of HFs were significantly higher than in plasma exosomes of OC patients, while the levels of these microRNAs in exosomes from plasma and ascites of ill females showed no difference. Our study revealed a strong direct correlation between the change in the ascites exosomes CD151+Tspan8+ subpopulation level and the expression levels of the ascites (R = 0.81, p < 0.05) and plasma exosomal miR-24 (R = 0.74, p < 0.05) in OC patients, which confirms the assumption that exosomal cargo act synergistically to increase cellular motility, affecting cellular processes and signaling. Bioinformatics analysis confirmed the involvement of CD151 and Tspan8 tetraspanins and genes controlled by miR-24-3p and miR-101 in signaling pathways, which are crucial for carcinogenesis, demonstrating that these tetraspanins and microRNAs are potential biomarkers for OC screening, and predictors of poor clinicopathological behavior in tumors.

Tetraspanin-enriched Microdomain Containing CD151, CD9, and TSPAN 8 - Potential Mediators of Entry and Exit Mechanisms in Respiratory Viruses Including SARS-CoV-2

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which originated in Wuhan, the Hubei region of China, has become a pandemic worldwide. It can transmit through droplets and enter via oral, nasal, and eye mucous membranes. It consists of single-stranded RNA (positive-sense), nonstructural proteins including enzymes and transcriptional proteins, and structural proteins such as Spike, Membrane, Envelope, and Nucleocapsid -proteins. SARS-CoV-2 mediates S-proteins entry and exit via binding to host cell surface proteins like tetraspanins. The transmembrane tetraspanins, CD151, CD9, and tetraspanin 8 (TSPAN8), facilitate the entry of novel coronaviruses by scaffolding host cell receptors and proteases. Also, CD151 was reported to increase airway hyperresponsiveness to calcium and nuclear viral export signaling. They may facilitate entry and exit by activating the serine proteases required to prime S-proteins in tetraspanin-enriched microdomains (TEMs). This article updates recent advances in structural proteins, their epitopes and putative receptors, and their regulation by proteases associated with TEMs. This review furnishes recent updates on the role of CD151 in the pathophysiology of SARS-CoV-2. We describe the role of CD151 in a possible mechanism of entry and exit in the airway, a major site for infection of SARS-CoV-2. We also updated current knowledge on the role of CD9 and TSPAN 8 in the entry and exit mechanism of coronaviruses. Finally, we discussed the importance of some small molecules which target CD151 as possible targeted therapeutics for COVID-19. In conclusion, this study could identify new targets and specific therapeutics to control emerging virus infections.

Basement membrane defects in CD151-associated glomerular disease

BACKGROUND

CD151 is a cell-surface molecule of the tetraspanin family. Its lateral interaction with laminin-binding integrin ɑ3β1 is important for podocyte adhesion to the glomerular basement membrane (GBM). Deletion of Cd151 in mice induces glomerular dysfunction, with proteinuria and associated focal glomerulosclerosis, disorganisation of GBM and tubular cystic dilation. Despite this, CD151 is not routinely screened for in patients with nephrotic-range proteinuria. We aimed to better understand the relevance of CD151 in human kidney disease.

METHODS

Next-generation sequencing (NGS) was used to detect the variant in CD151. Electron and light microscopy were used to visualise the filtration barrier in the patient kidney biopsy, and immunoreactivity of patient red blood cells to anti-CD151/MER2 antibodies was performed. Further validation of the CD151 variant as disease-causing was performed in zebrafish using CRISPR-Cas9.

RESULTS

We report a young child with nail dystrophy and persistent urinary tract infections who was incidentally found to have nephrotic-range proteinuria. Through targeted NGS, a novel, homozygous truncating variant was identified in CD151, a gene rarely reported in patients with nephrotic syndrome. Electron microscopy imaging of patient kidney tissue showed thickening of GBM and podocyte effacement. Immunofluorescence of patient kidney tissue demonstrated that CD151 was significantly reduced, and we did not detect immunoreactivity to CD151/MER2 on patient red blood cells. CRISPR-Cas9 depletion of cd151 in zebrafish caused proteinuria, which was rescued by injection of wild-type CD151 mRNA, but not CD151 mRNA containing the variant sequence.

CONCLUSIONS

Our results indicate that a novel variant in CD151 is associated with nephrotic-range proteinuria and microscopic haematuria and provides further evidence for a role of CD151 in glomerular disease. Our work highlights a functional testing pipeline for future analysis of patient genetic variants. A higher resolution version of the Graphical abstract is available as Supplementary information.

Rapid immunomagnetic co-capture assay for quantification of lung Cancer associated exosomes

Exosomes derived from biological fluids have the potential to serve as a biomarker for the early detection of various cancers. However, the lack of reliable enrichment and detection methods posed a challenge for its clinical utility. In this work, we designed a rapid co-capture-based approach for targeted enrichment and detection of lung cancer-derived exosomes from human plasma. This method relies on the formation of a sandwich complex around the exosomes that involves magnetic nanoparticles coupled to CD151 to assist in the immunomagnetic selection of lung-derived exosomes and a secondary detection antibody (CD81) coupled to horseradish peroxidase for signal amplification. The performance of the co-capture method to detect exosomes has been optimized with known exosome concentrations in human plasma and exhibited good linearity (10⁸-10⁵ exosomes mL^-1) with a detection limit of 60.4 exosomes μL^-1. This study further investigated the potential of the developed assay to differentiate healthy and lung cancer patients using 18 clinical samples by quantifying the CD151+/ CD81+ lung-derived exosomes. In conclusion, this study demonstrated a rapid co-capture-based approach that offers simultaneous isolation and detection of exosomes compatible with low sample volume for detecting lung cancer patients.

New Report of a Different Clinical Presentation of CD151 Splicing Mutation (c.351+2T>C): Could TSPAN11 be Considered as a Potential Modifier Gene for CD151?

CD151, a member of the tetraspanin family, is essential for normal development of skin and kidney. To date, only 2 pathogenic variants of the CD151 gene have been identified in a related disorder with recessive inheritance. Here, in the third study of CD151 mutations, we report 3 affected siblings presenting variable degrees of renal and dermal symptoms. Whole exome sequencing (WES) was performed on the proband, followed by data analysis and in silico assessments. Confirmation of the mutation in the other patients were carried out using Sanger sequencing. The consequence of the CD151 mutation was investigated by RNA extraction and Sanger sequencing of PCR products from cDNA. Multiple computational tools were applied for protein alignment, homology modeling, and molecular interaction analysis. WES revealed the variant c.351+2T>C, NM_139029 (GRCh37) in CD151, and this was confirmed by Sanger sequencing in all patients. This variant is the result of a substitution of nucleotide T with C that changes the position +2 of the donor splice site in intron 5, leading to total loss of exon 5 from the transcript. The mentioned variant was not found in population allele frequency databases, and prediction tools concurred in its damaging effect on the protein. Based on the criteria from ACMG guidelines, this variant is pathogenic. Interestingly, in terms of clinical findings, symptoms and severity of the disease in the patients in this study were different compared to the previous report of the mutation and the disease. In addition, in silico analysis in this study appears to suggest a candidate protein, Tetraspanin-11 (TSPAN11), that could partially modify CD151 functions. This study supports the pathogenic effect of the CD151 variant c.351+2T>C, highlights the extensive variable expressivity amongst patients, reinforces the contribution of genomic content to clinical characteristics of CD151 mutations, and accentuates the importance of modifier genes.

Tetraspanins: Host Factors in Viral Infections

Tetraspanins are transmembrane glycoproteins that have been shown increasing interest as host factors in infectious diseases. In particular, they were implicated in the pathogenesis of both non-enveloped (human papillomavirus (HPV)) and enveloped (human immunodeficiency virus (HIV), Zika, influenza A virus, (IAV), and coronavirus) viruses through multiple stages of infection, from the initial cell membrane attachment to the syncytium formation and viral particle release. However, the mechanisms by which different tetraspanins mediate their effects vary. This review aimed to compare and contrast the role of tetraspanins in the life cycles of HPV, HIV, Zika, IAV, and coronavirus viruses, which cause the most significant health and economic burdens to society. In doing so, a better understanding of the relative contribution of tetraspanins in virus infection will allow for a more targeted approach in the treatment of these diseases.

Nanoparticle-Aided Detection of Colorectal Cancer-Associated Glycoconjugates of Extracellular Vesicles in Human Serum

Extracellular vesicles (EVs) are found in all biological fluids, providing potential for the identification of disease biomarkers such as colorectal cancer (CRC). EVs are heavily glycosylated with specific glycoconjugates such as tetraspanins, integrins, and mucins, reflecting the characteristics of the original cell offering valuable targets for detection of CRC. We report here on europium-nanoparticle (EuNP)-based assay to detect and characterize different surface glycoconjugates of EVs without extensive purification steps from five different CRC and the HEK 293 cell lines. The promising EVs candidates from cell culture were clinically evaluated on small panel of serum samples including early-stage (n = 11) and late-stage (n = 11) CRC patients, benign condition (n = 11), and healthy control (n = 10). The majority of CRC cell lines expressed tetraspanin sub-population and glycovariants of integrins and conventional tumor markers. The subpopulation of CD151 having CD63 expression (CD151^CD63) was significantly (p = 0.001) elevated in early-stage CRC (8 out of 11) without detecting any benign and late-stage samples, while conventional CEA detected mostly late-stage CRC (p = 0.045) and with only four early-stage cases. The other glycovariant assays such as CEA^Con-A, CA125^WGA, CA 19.9^Ma696, and CA 19.9^Con-A further provided some complementation to the CD151^CD63 assay. These results indicate the potential application of CD151^CD63 assay for early detection of CRC patients in human serum.

CD151 enrichment in exosomes of luminal androgen receptor breast cancer cell line contributes to cell invasion

Breast cancer is the most common and highly heterogeneous disease in women worldwide. Given the challenges in the treatment of advanced metastatic breast cancer, it is necessary to understand the molecular mechanisms related to disease progression. Exosomes play various roles in the progression of tumors, including promoting the invasion and advancing the distant metastasis. To study the molecular mechanisms related to the progression of luminal androgen receptor (LAR) breast cancer, we first isolated exosomes of MDA-MB-453 cells, a representative cell line of LAR. Through quantitative proteomic analysis, we identified 180 proteins specifically enriched in exosomes after comparing with those in cells, microvesicles, and the 150K supernatant. Among these, CD151, a protein involved in the regulation of cell motility was the most enriched one. CD151-knockdown exosomes reduced the invasion ability of the recipient breast cancer cell and lowered the phosphorylation level of tyrosine-protein kinase Lck, indicating that the invasion of LAR breast cancer may be due to CD151-enriched exosomes. Our work reports for the first time that CD151 was highly abundant in the exosomes of MDA-MB-453 cells and expands the understanding of the development process of LAR subtype, suggesting CD151 may be a potential candidate for the treatment of LAR breast cancer.

CD151 drives cancer progression depending on integrin α3β1 through EGFR signaling in non-small cell lung cancer

Background

Tetraspanins CD151, a transmembrane 4 superfamily protein, has been identified participating in the initiation of a variety of cancers. However, the precise function of CD151 in non-small cell lung cancer (NSCLC) remains unclear. Here, we addressed the pro-tumoral role of CD151 in NSCLC by targeting EGFR/ErbB2 which favors tumor proliferation, migration and invasion.

Methods

First, the mRNA expression levels of CD151 in NSCLC tissues and cell lines were measured by RT-PCR. Meanwhile, CD151 and its associated proteins were analyzed by western blotting. The expression levels of CD151 in NSCLC samples and its paired adjacent lung tissues were then verified by Immunohistochemistry. The protein interactions are evaluated by co-immunoprecipitation. Flow cytometry was applied to cell cycle analysis. CCK-8, EdU Incorporation, and clonogenic assays were used to analyze cell viability. Wound healing, transwell migration, and matrigel invasion assays were utilized to assess the motility of tumor cells. To investigate the role of CD151 in vivo, lung carcinoma xenograft mouse model was applied.

Results

High CD151 expression was identified in NSCLC tissues and cell lines, and its high expression was significantly associated with poor prognosis of NSCLC patients. Further, knockdown of CD151 in vitro inhibited tumor proliferation, migration, and invasion. Besides, inoculation of nude mice with CD151-overexpressing tumor cells exhibited substantial tumor proliferation compared to that in control mice which inoculated with vector-transfected tumor cells. Noteworthy, we found that overexpression of CD151 conferred cell migration and invasion by interacting with integrins. We next sought to demonstrate that CD151 regulated downstream signaling pathways via activation of EGFR/ErbB2 in NSCLC cells. Therefore, we infer that CD151 probably affects the sensitivity of NSCLC in response to anti-cancer drugs.

Conclusions

Based on these results, we demonstrated a new mechanism of CD151-mediated tumor progression by targeting EGFR/ErbB2 signaling pathway, by which CD151 promotes NSCLC proliferation, migration, and invasion, which may considered as a potential target of NSCLC treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-01998-4.

Downregulation of CD151 restricts VCAM-1 mediated leukocyte infiltration to reduce neurobiological injuries after experimental stroke

Background

Translational failures in anti-adhesion molecule therapies after stroke reveal the necessity of developing new strategies that not only interrupt leukocyte recruitment but also consider the inhibition of endothelial cell inflammation, verification of therapeutic time window, and normal function maintenance of circulating leukocytes. Our study focused on the potential therapeutic value of CD151 downregulation in improving current anti-adhesion molecule therapies.

Methods

Lentivirus intracerebroventricular administration was conducted to inhibit the CD151 expression and observe its functional influence on neurological injuries and outcomes. Then, immunohistochemistry and myeloperoxidase activity assessment were performed to explore the effects of CD151 expression on neutrophil and monocyte recruitment after rat cerebral ischemia. Primary rat brain microvascular endothelial cells were subjected to oxygen glucose deprivation and reoxygenation to elucidate the underlying working mechanisms between CD151 and VCAM-1.

Results

The CD151 downregulation remarkably reduced neurological injuries and improved neurological outcomes, which were accompanied with reduced neutrophil and monocyte infiltration after the CD151 downregulation. The VCAM-1 expression was remarkably decreased among the adhesion molecules on the endothelial cell responsible for neutrophil and monocyte infiltration. The activation of p38 MAPK and NF-κB pathways was restricted after the CD151 downregulation. p38 MAPK and NF-κB inhibitors decreased the VCAM-1 expression, and p38 acted as an upstream regulator of NF-κB. However, CD151 downregulation did not directly influence the neutrophil and monocyte activation.

Conclusions

Overall, CD151 regulated the expression of adhesion molecules. It also played a critical role in suppressing VCAM-1-mediated neutrophil and monocyte infiltration via the p38/NF-κB pathway. This study possibly provided a new basis for improving current anti-adhesion molecule therapies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-021-02171-6.

The Context-Dependent Impact of Integrin-Associated CD151 and Other Tetraspanins on Cancer Development and Progression: A Class of Versatile Mediators of Cellular Function and Signaling, Tumorigenesis and Metastasis

Simple Summary

Tetraspanins are a family of molecules abundantly expressed on the surface of normal or tumor cells. They have been implicated in recruiting or sequestering key molecular regulators of malignancy of a variety of human cancers, including breast and lung cancers, glioblastoma and leukemia. Yet, how their actions take place remains mysterious due to a lack of traditional platform for molecular interactions. The current review digs into this mystery by examining findings from recent studies of multiple tetraspanins, particularly CD151. The molecular basis for differential impact of tetraspanins on tumor development, progression, and spreading to secondary sites is highlighted, and the complexity and plasticity of their control over tumor cell activities and interaction with their surroundings is discussed. Finally, an outlook is provided regarding tetraspanins as candidate biomarkers and targets for the diagnosis and treatment of human cancer.

Abstract

As a family of integral membrane proteins, tetraspanins have been functionally linked to a wide spectrum of human cancers, ranging from breast, colon, lung, ovarian, prostate, and skin carcinomas to glioblastoma. CD151 is one such prominent member of the tetraspanin family recently suggested to mediate tumor development, growth, and progression in oncogenic context- and cell lineage-dependent manners. In the current review, we summarize recent advances in mechanistic understanding of the function and signaling of integrin-associated CD151 and other tetraspanins in multiple cancer types. We also highlight emerging genetic and epigenetic evidence on the intrinsic links between tetraspanins, the epithelial-mesenchymal transition (EMT), cancer stem cells (CSCs), and the Wnt/β-catenin pathway, as well as the dynamics of exosome and cellular metabolism. Finally, we discuss the implications of the highly plastic nature and epigenetic susceptibility of CD151 expression, function, and signaling for clinical diagnosis and therapeutic intervention for human cancer.

Activation of GPER by E2 promotes proliferation, invasion and migration of breast cancer cells by regulating the miR-124/CD151 pathway

Breast cancer is one of the most common malignancies worldwide and is responsible for a high mortality rate. However, the underlying pathological mechanism of breast cancer remains unclear. MicroRNAs (miRNAs/miRs) play critical roles in the progression of breast cancer. Recent studies have reported that miR-124/CD151 participates in the development of breast cancer. However, the exact molecular mechanism of miR-124/CD151 action in 17β-estradiol (E2)-treated breast cancer cells remains unknown. Thus, the present study aimed to investigate miR-124 and CD151 expression levels in MCF-7 cells treated with E2 via reverse transcription-quantitative PCR and western blot analyses. Bioinformatic analysis was performed to predict and identify whether CD151 is a potential target of miR-124. The Cell Counting Kit-8 and colony formation assays were performed to detect proliferation of MCF-7 cells. In addition, the invasive and migratory abilities of MCF-7 cells were assessed via the Transwell and wound healing assays, respectively. The results demonstrated that E2 downregulated miR-124 expression, while upregulating G protein -coupled estrogen receptor (GPER) expression in MCF-7 cells. Following treatment with the GPER antagonist, G15, miR-124 expression was significantly enhanced and E2-induced proliferation, invasion and migration of MCF-7 cells were notably inhibited. In addition, CD151 was confirmed as a direct target of miR-124. CD151 silencing remarkably suppressed the proliferation, invasion and migration of E2-induced MCF-7 cells. Taken together, these results suggest that upregulation of GPER expression induced by E2 promotes proliferation, invasion and migration of breast cancer cells by regulating the miR-124/CD151 pathway. Thus, the results of the present study provide a potential novel method for the treatment and prognosis of breast cancer.

Exosomal Protease Cargo as Prognostic Biomarker in Colorectal Cancer

Objective:

The aim of the study was to develop a model for predicting cancer risk in colorectal polyps’ patients (CPPs), as well as to reveal additional prognosis factors for Stage III colorectal cancer based on differences in subpopulations of tetraspanins, tetraspanin-associated and tetraspanin-non-associated proteases in blood plasma exosomes of CPPs and colorectal cancer patients (CRCPs).

Methods:

The subpopulations of CD151- and Tspan8-positive exosomes, the subpopulations of metalloproteinase at the surface of СD9-positive exosomes and the level of 20S proteasomes in plasma exosomes in 15 CPPs (tubulovillous adenomas) and 60 CRCPs were evaluated using flow cytometry and Western blotting. Logistic regression analysis was performed to predict cancer risk of CPPs.

Results:

The levels of 20S proteasomes in exosomes, MMP9+, MMP9+/MMP2+/EMMPRIN+ in CD9-positive blood plasma exosomes are associated with the risk of malignant transformation of colorectal tubulovillous adenomas. In patients with Stage III CRC, the levels of 20S proteasomes (less than 2 units) and MMP9+ subpopulations (more than 61%) in plasma exosomes are unfavorable prognostic factors for overall survival. The levels of 20S proteasomes and ADAM10+/ADAM17- subpopulations in CD9-positive blood plasma exosomes are the most significant values for predicting relapse-free survival.

Conclusion:

Protease cargo in CD9-positive blood plasma exosomes is prognostic biomarker for colorectal polyps and colorectal cancer.

Downregulation of CD151 induces oxidative stress and apoptosis in trophoblast cells via inhibiting ERK/Nrf2 signaling pathway in preeclampsia

Preeclampsia (PE) is a pregnancy-related syndrome characterized by new-onset hypertension and proteinuria after gestational 20 weeks. Oxidative stress, resulting from the imbalance between the production of oxidants and antioxidants in placentas, is recognized as a key pathology of PE. To date, the molecules that regulate antioxidants production remain unclear. CD151, a member of tetraspanins, is an important regulator of many physiological functions. However, the function of CD151 in oxidative stress and its association with pregnancy-related complications are currently unknown. In the present study, we have demonstrated that CD151 was a key regulator of antioxidants in placentas. Compared with the placentas of the controls, the placentas of PE patients exhibited decreased CD151 expression accompanying with decreased antioxidant gene expression (HO-1, NQO-1, GCLC and SOD-1). In vitro, overexpression of CD151 in trophoblast cells could enhance HO-1, NQO-1, GCLC and SOD-1 expression but downregulation of CD151 decreased those antioxidant genes expression, which indicates CD151 is the upstream of antioxidants. Importantly, the phenotype of PE (hypertension and proteinuria) was mimicked in the downregulating CD151 induced mouse model. Moreover, the beneficial effect of CD151 in trophoblast cells was hindered when ERK and Nrf2 signaling were blocked. Overall, our results revealed CD151 might be a new target for PE treatment.

CD151 promotes Colorectal Cancer progression by a crosstalk involving CEACAM6, LGR5 and Wnt signaling via TGFβ1

CD151 impacts various signaling pathways in different cancers, and promotes colorectal cancer (CRC) cell malignancy by yet undefined mechanisms. This study aimed to comprehensively assess CD151's function in CRC. CD151 levels were significantly higher in CRC tissues and cells compared with controls in the tissue microarray. Cell viability, migration and invasion were suppressed by CD151 downregulation in CRC cells. Consistently, mouse xenografts were inhibited by CD151 silencing. RNA-seq revealed that multiple genes were significantly altered by CD151 knockdown in cultured CRC cells and xenografts. Particularly, transforming growth factor β1 (TGFβ1), carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) and leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5) alongside CD151 were downregulated both in vitro and in vivo. Co-immunoprecipitation and mass spectrometry results were validated by qRT-PCR and immunoblot. Moreover, pull-down assay and immunofluorescence confirmed the associations of TGFβ1, CEACAM6 and LGR5 with CD151. This study demonstrated CEACAM6, LGR5 and Wnt pathway suppression by CD151 silencing might occur through TGFβ1 regulation, offering a comprehensive view of CD151's roles in colorectal carcinogenesis. Our findings provide an insight into the CD151-involved signaling network in CRC oncogenesis, which could be utilized to design novel targeted therapies against CD151-based signaling in treatment for CRC.

Negative correlation of urinary miR-199a-3p level with ameliorating effects of sarpogrelate and cilostazol in hypertensive diabetic nephropathy

The prevalence of chronic kidney disease is increasing globally; however, effective therapeutic options are limited. In this study, we aimed to identify urinary miRNAs reflecting the effect of therapeutic intervention in rats with comorbid hypertension and diabetes. Additionally, the potential beneficial effects of anti-platelet sarpogrelate and cilostazol were investigated. Nephropathy progression in streptozotocin (STZ)-treated spontaneously hypertensive rats (SHRs), including albuminuria, collagen deposition, and histopathological changes, was alleviated by sarpogrelate and antihypertensive agent telmisartan. Global analysis of urinary miRNAs identified that miR-199a-3p was commonly reduced by sarpogrelate and telmisartan treatment. In vitro analysis suggested CD151 as a target gene of miR-199a-3p: miR-199a-3p overexpression repressed CD151 levels and miR-199a-3p interacted with the 3'-untranslated region of the CD151 gene. In addition, we demonstrated that the miR-199a-3p/CD151 axis is associated with the transforming growth factor-β1 (TGF-β1)-induced fibrogenic pathway. TGF-β1 treatment led to miR-199a-3p elevation and CD151 suppression, and miR-199a-3p overexpression or CD151-silencing enhanced TGF-β1-inducible collagen IV and α-smooth muscle actin (α-SMA) levels. In vivo analysis showed that the decrease in CD151 and the increase in collagen IV and α-SMA in the kidney from STZ-treated SHR were restored by sarpogrelate and telmisartan administration. In an additional animal experiment using cilostazol and telmisartan, there was a correlation between urinary miR-199a-3p reduction and the ameliorating effects of cilostazol or combination with telmisartan. Collectively, these results indicate that urinary miR-199a-3p might be utilized as a marker for nephropathy treatment. We also provide evidence of the benefits of antiplatelet sarpogrelate and cilostazol in nephropathy progression.

Key Role of CD151-integrin Complex in Lung Cancer Metastasis and Mechanisms Involved

Tetraspanin CD151 was found to be upregulated in malignant cell types and has been identified as a tumor metastasis promoter. In this study, we aimed to examine the role of the CD151-integrin complex in lung cancer metastasis and the underlying mechanisms. CD151 QRD^194-196 →AAA^194-196 mutant was generated and used to transfect A549 human lung adenocarcinoma cells. We found that there was no significant difference in CD151 protein expression between CD151 and CD151-AAA mutant groups. In vitro, CD151-AAA mutant delivery abrogated the migration and invasion of A549 cells, which was promoted by CD151 gene transfer. Furthermore, CD151-AAA delivery failed to activate FAK and p130Cas signaling pathways. Western blot and immunohistochemical staining showed strong CD151 expression in lung cancerous tissues but not in adjacent normal tissues. Increased level of CD151 protein was observed in 20 of the patients and the positive rate of CD151 protein in specimens was 62.5% (20/32). In addition, CD151 was co-localized with α3 integrin at the cell-cell contact site in carcinoma tissues. These results suggested that the disruption of the CD151-α3 integrin complex may impair the metastasis-promoting effects and signaling events induced by CD151 in lung cancer. Our findings identified a key role for CD151-α3 integrin complex as a promoter in the lung cancer.

CD151 Alleviates Early Blood-Brain Barrier Dysfunction After Experimental Focal Brain Ischemia in Rats

Preservation of the blood-brain barrier (BBB) function is a potential protective strategy against cerebral ischemic injuries. CD151 has a beneficial effect in maintaining vascular stability and plays a role in pro-angiogenesis. Both vascular stability and angiogenesis can affect BBB function. Therefore, we aimed to examine the action of CD151 in regulating BBB permeability after cerebral ischemic injury in the present study. Using a transient focal cerebral ischemia (tFCI) rat model, we established that CD151 overexpression in the brain mitigated the leakage of endogenous IgG at 6-24 h after tFCI in vivo. Moreover, we found that CD151 can decrease the diffusion of macromolecules through monolayer brain microvessel endothelial cells (BMVECs) after glucose and oxygen deprivation (OGD)-reoxygenation in vitro. Furthermore, overexpression of CD151 in BMVECs suppressed OGD-reoxygenation-induced F-actin formation and RhoA activity. However, while preserving BBB integrity after tFCI, CD151 overexpression did not affect the post-stroke outcomes. Taken together, the present study demonstrated that CD151 overexpression in the brain protects BBB permeability at early phase after tFCI. CD151 may be a potential target for early BBB protection in ischemic stroke.

Composition of hemidesmosomes in basal keratinocytes of normal buccal mucosa and oral lichen planus

Oral lichen planus (OLP) is a chronic inflammatory disease displaying ultrastructural disturbances in epithelial hemidesmosomes. The expression of several key hemidesmosomal components in OLP as well as in normal buccal mucosa is, however, unknown. The aim of the study was therefore to examine intracellular and extracellular components involved in hemidesmosomal attachment, in OLP (n = 20) and in normal buccal mucosa (n = 10), by immunofluorescence. In normal buccal mucosa, laminin-α3γ2, integrin-α6β4, CD151, collagen α-1(XVII) chain, and dystonin showed linear expression along the basal membrane, indicating the presence of type I hemidesmosomes. Plectin stained most epithelial cell membranes and remained unphosphorylated at S4642. In OLP, most hemidesmosomal molecules examined showed disturbed expression consisting of discontinuous increases, apicolateral location, and/or intracellular accumulation. Plectin showed S4642-phosphorylation at the basement membrane, and deposits of laminin-α3 and laminin-γ2 were found within the connective tissue. The disturbed expression of hemidesmosomal proteins in OLP indicates deficient attachment of the basal cell layer, which can contribute to detachment and cell death of basal keratinocytes seen in the disease.

Molecular modeling and in vitro study on pyrocatechol as potential pharmacophore of CD151 inhibitor

CD151 has been recognized as a prognostic marker, the therapeutic target of breast cancers, but less explored for small molecule inhibitors due to lack of a validated model. The 3-D structure of CD151 large extracellular loop (LEL) was modeled using the LOMETS server and validated by the Ramachandran plot. The validated structure was employed for molecular docking and structure-based pharmacophore analysis. Druglikeness was evaluated by the ADMET description protocol. Antiproliferative activity was evaluated by MTT, BrdU incorporation, flow cytometry, and cell death ELISA^PLUS assay. This study predicted the best model for CD151-LEL with 94.1% residues in favored regions and Z score -2.79 kcal/mol using the threading method. The web-based receptor cavity method identified one functional target site, which was suitable for the binding of aromatic and heterocyclic compounds. Molecular docking study identified pyrocatechol (PCL) and 5-fluorouracil (FU) as potential leads of CD151-LEL. The pharmacophore model identified interaction points of modeled CD151-LEL with PCL and FU. Also, the analysis of ADMET properties revealed the drug-likeness of PCL and FU. The viability of MDA-MB 231 cells was significantly reduced with PCL and FU but less affected MCF-12A, normal healthy breast epithelial cell line. With 50% toxic concentration, both PCL and FU significantly inhibited 82.46 and 87.12% proliferation, respectively, of MDA-MB 231 cells by altering morphology and inducing G1 cell cycle arrest and apoptosis. In addition, PCL and FU inhibited the CD151 expression by 4.5-and 4.8-folds, respectively. This study suggests the further assessment of pyrocatechol as a potential lead of CD151 in breast cancer at the molecular level.

HPV caught in the tetraspanin web?

Tetraspanins are master organizers of the cell membrane. Recent evidence suggests that tetraspanins themselves may become crowded by virus particles and that these crowds/aggregates co-internalize with the viral particles. Using microscopy, we studied human papillomavirus (HPV) type 16-dependent aggregates on the cell surface of tetraspanin overexpressing keratinocytes. We find that aggregates are (1) rich in at least two different tetraspanins, (2) three-dimensional architectures extending up to several micrometers into the cell, and (3) decorated intracellularly by filamentous actin. Moreover, in cells not overexpressing tetraspanins, we note that obscurin-like protein 1 (OBSL1), which is thought to be a cytoskeletal adaptor, associates with filamentous actin. We speculate that HPV contact with the cell membrane could trigger the formation of a large tetraspanin web. This web may couple the virus contact site to the intracellular endocytic actin machinery, possibly involving the cytoskeletal adaptor protein OBSL1. Functionally, such a tetraspanin web could serve as a virus entry platform, which is co-internalized with the virus particle.

Tetraspanins in mammalian reproduction: spermatozoa, oocytes and embryos

It is known that tetraspanin proteins are involved in many physiological somatic cell mechanisms. Additionally, research has indicated they also have a role in various infectious diseases and cancers. This review focuses on the molecular interactions underlying the tetraspanin web formation in gametes. Primarily, tetraspanins act in the reproductive tract as organizers of membrane complexes, which include the proteins involved in the contact and association of sperm and oocyte membranes. In addition, recent data shows that tetraspanins are likely to be involved in these processes in a complex way. In mammalian fertilization, an important role is attributed to CD molecules belonging to the tetraspanin superfamily, particularly CD9, CD81, CD151, and also CD63; mostly as part of extracellular vesicles, the significance of which and their potential in reproduction is being intensively investigated. In this article, we reviewed the existing knowledge regarding the expression of tetraspanins CD9, CD81, CD151, and CD63 in mammalian spermatozoa, oocytes, and embryos and their involvement in reproductive processes, including pathological events.

Integrin-associated CD151 is a suppressor of prostate cancer progression

Owing to the complexity of interacting molecular networks on the cell surface, integrin-associated tetraspanin CD151 remains controversial regarding its clinical importance and functional impact in prostate cancer. The current study evaluated dynamics and clinical importance of CD151 expression and its function in prostate cancer by IHC analysis of two independent patient cohorts (n=80, 181), bioinformatic interrogation of the TCGA database, and evaluation of gene knockdown effect at the cellular level. Our data showed that aside from high mRNA expression, CD151 was primarily localized to intercellular junctions at the plasma membrane in normal prostate glands or benign tissues, regardless of nature of antibodies used. By contrast, in primary tumors from patients with metastatic disease, CD151 was largely localized in the cytosol. Furthermore, the level of the cell-cell junction-linked CD151 was inversely associated with Gleason grade and tumor stage (P<0.001 for both). The portion of primary tumors expressing junctional CD151 was also three-fold less in the metastatic patient population than its counterpart (P<0.001). In line with these observations, CD151 and its associated α3β1 or α6β4 integrin inversely correlated with androgen receptor (AR) at the mRNA level (Spearman coefficient: -0.44, -0.48 and -0.42) in the TCGA cohort. Expression of these adhesion molecules also correlated with DNA methylation in their promoters (Spearman coefficient: -0.37, -0.71 and -0.82). Combined, these data suggest that CD151 and associated integrins are linked to tumor metastasis through AR and the epigenetic program. Meanwhile, CD151 knockdown in E-cadherin-positive tumor cells led to increased cell proliferation and induction of the epithelial-mesenchymal transition (EMT)-like phenotype. Given the strong RGD-binding integrin dependence of EMT-featured tumor cells, we examined focal adhesion kinase (FAK), their key signaling effector, in the above patient cohorts. In contrast to CD151, FAK exhibited positive correlation with tumor grade and stage as well as AR and p53 inactivation at either mRNA, protein or genomic level. Taken together, our results suggest that CD151 represses prostate cancer by antagonizing cell proliferation, EMT and the signaling of RGD-binding integrins. Since this anti-tumorigenic role is prone to the AR-mediated transcriptional and epigenetic regulation, CD151 and possibly α3β1 and α6β4 integrins are of potential biomarkers for metastatic prostate cancer.

EM2D9, A monoclonal antibody against integrin α5β1, has potent antitumor activity on endometrial cancer in vitro and in vivo

Endometrial cancer, a type of primary epithelial malignant tumor in the endometrium, is one of the three most common malignant tumors of the female reproductive system. While the incidence of endometrial cancer has been recently rising, its etiology remains unclear. In this study we found that EM2D9, an independently developed monoclonal antibody, specifically recognized endometrial cancer cells; we further determined that EM2D9 target protein was α5β1. In vitro and in vivo experiments showed that EM2D9 inhibited the migration of endometrial cancer cells. Real-time quantitative PCR results showed that the expression of CD151 mRNA in endometrial carcinoma cells significantly decreased after EM2D9 treatment. We also found that EM2D9 affected the FAK signaling pathway. Collectively, these results shed light on a new mechanism for the development of endometrial carcinoma.

CD151 in Respiratory Diseases

The tetraspanin, Cluster of Differentiation 151 (CD151), is ubiquitously expressed in adult tissue, especially in the lungs where it has been implicated in lung cancer, asthma, influenza, and idiopathic pulmonary fibrosis (IPF). CD151 interacts with laminin-binding integrins and growth factor receptors, and is reported in cancer-promoting processes such as tumor initiation, metastasis, and angiogenesis. In asthma, CD151 was shown to promote airways hyperresponsiveness through calcium signaling whereas in influenza, CD151 was shown to be a novel host factor for nuclear viral export signaling. Furthermore, CD151 was shown to be associated with increased disease severity and poorer survival outcome in asthma and lung cancer, respectively. In this review, we provide an update on the current understanding of CD151 with regards to its contribution to lung pathophysiology. We also summarize factors that have been shown to regulate CD151 expression and identify key areas that need to be taken into consideration for its utility as a screening or prognostic tool in disease management and/or as a therapeutic target for the treatment of lung diseases.

The activation of GPER inhibits cells proliferation, invasion and EMT of triple-negative breast cancer via CD151/miR-199a-3p bio-axis

Background: Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype. G protein coupled receptor (GPER), the key player in the intercellular signaling communication, has been verified to participate in tumorigenesis. The present study aims to explore the effects of GPER on cell proliferation, invasion and EMT through CD151/miR-199a-3p bio-axis in TNBC cells. Methods: Total proteins were isolated from TNBC cell lines and GPER expression was determined using western blot assay. CCK-8 assay was used to detect cell viability after being treated with GPER activation. Western blotting and immunofluorescence were applied to measure the level of proteins associated with cell proliferation, angiogenesis and EMT, as well as the Hippo signal pathway. The level of miR-199a-3p and transfection efficiency were evaluated by reverse transcriptase quantitative PCR (RT-qPCR) after being transfected with miR-199a-3p mimics. Cell migration and invasion of TNBC cells were assessed by wound healing and transwell assays. Moreover, luciferase reporter assay was conducted to verify the relationship between CD151 and miR-199a-3p. Results: GPER activation treatment suppressed MDA-MB-231 cell viability, proliferation, migration, invasion, angiogenesis and EMT process. The expression of E-cadherin was increased, but N-cadherin, Vimentin, VEGFA, AngII and CD151 were decreased after GPER activation treatment. Conversely, inhibition of GPER indeed up-regulated CD151 expression. In addition, overexpression of miR-199a-3p supressed cell proliferation, migration, invasion and angiogenesis, as well as EMT process and the Hippo signal pathway. Conclusion: Collectively, the activation of GPER inhibits cells proliferation, invasion and EMT of triple-negative breast cancer via CD151/miR-199a-3p bio-axis. This study provides a novel intervention target for the treatment of breast cancer cells and a fresh idea for the clinical therapy of breast cancer.

Mortalin stabilizes CD151-depedent tetraspanin-enriched microdomains and implicates in the progression of hepatocellular carcinoma

Background: Our previous studies showed that tetraspanin CD151 was implicated in the progression of hepatocellular carcinoma (HCC), mainly depending on the formation of functional complexes with molecular partners, including Mortalin. In this study, we investigate the role of mortalin in CD151-depedent progression of HCCs.

Methods: Immunofluorescent staining, western blot and quantitative real-time polymerase chain reaction (qRT-PCR) were used to investigate the expression and location of CD151 and Mortalin in four HCC cell lines with different metastatic ability. The relationship between Mortalin and CD151 was investigated in HCCLM3 cells using co-immunoprecipitation. CD151 or Mortalin expression in HCC cells were modified by transfection technology. Wound-healing assay and Transwell assay were used to assay the role of CD151 and Mortalin in cell migration and invasion. The expression and prognostic implication of CD151 and Mortalin in 187 cases of HCCs were analyzed.

Results: Expression of Mortalin in HCC cells was positive related to their metastatic ability and its tendency was in line with the expression of CD151. Immunofluorescent staining showed that Mortalin was located in cytoplasm, while positive staining for CD151 was observed in cytoplasm and membrane of HCC cells. co-IP revealed that Mortalin formed a complex with CD151. Down-regulation of Mortalin induced a moderate decreased CD151 protein, but not CD151 mRNA, while inhibition of CD151 did not influence the expression of Mortalin at the level of both protein and mRNA. Interference of Mortalin significantly inhibited the invasion and migration of HCC cells with high CD151 expression and partially restored the invasion and migration of HCC cells induced by CD151 over-expression. Clinically, high Mortalin expression correlated with malignant phenotype of HCC, such as microvascular invasion (p=0.017) and tumor diameter (p=0.001). HCC patients expressing high Mortalin were tend to have higher expression of CD151. HCC patients expressing high level of CD151 showed the poorer prognosis in a Mortalin-dependent manner.

Conclusions: Mortalin maybe stabilize of the structure of CD151-dependent tetraspanin-enriched microdomains and implicate in the progression of HCC.

Tetraspanin CD151 and integrin α3β1 contribute to the stabilization of integrin α6β4-containing cell-matrix adhesions

Tetraspanin CD151 has been suggested to regulate cell adhesion through its association with laminin-binding integrins α3β1 and α6β4; however, its precise function in keratinocyte adhesion remains elusive. In this study, we investigated the role of CD151 in the formation and maintenance of laminin-associated adhesions. We show that CD151, through binding to integrin α3β1, plays a critical role in the stabilization of an adhesion structure with a distinct molecular composition of hemidesmosomes with tetraspanin features. These hybrid cell-matrix adhesions, which are formed early during cell adhesion and spreading and at later stages of cell spreading, are present in the central region of the cells. They contain the CD151-α3β1/α6β4 integrin complexes and the cytoskeletal linker protein plectin, but are not anchored to the keratin filaments. In contrast, hemidesmosomes, keratin filament-associated adhesions that contain integrin α6β4, plectin, BP180 (encoded by COL17A1) and BP230 (encoded by DST), do not require CD151 for their formation or maintenance. These findings provide new insights into the dynamic and complex regulation of adhesion structures in keratinocytes and the pathogenic mechanisms underlying skin blistering diseases caused by mutations in the gene for CD151.

coli and a Structural Insight into Cholesterol Binding Domain

CD151 is an abundantly expressed eukaryotic transmembrane protein on the cell surface. It is involved in cell adhesion, angiogenesis and signal transduction as well in disease conditions such as cancer and viral infections. However, the molecular mechanism of CD151 activation is poorly understood due to the lack of structural information. By considering the difficulties in expressing the membrane protein in E. coli, herein we introduce the strategic design for the effective expression of recombinant CD151 protein in E. coli with high yield, that would aid for the structural studies. CD151 having four transmembrane domain (TMD's) along with small and a large extracellular loop (LEL) is constructed in parts to enhance the soluble expression of the protein attached with fusion tag. This has led to the high yield of the recombinant CD151 protein in the designed constructs. The recombinant CD151 protein is characterized and confirmed by western blot, CD and Mass peptide fingerprint. The molecular dynamics simulations (MDS) for the full-length CD151 shows conformational changes in the LEL of the protein in the presence and absence of cholesterol and indicate the certainty of closed and open conformation of CD151 based on cholesterol binding. The MDS results have led to the understanding of the possible underlying mechanism for the activation of the CD151 protein.

Expression of tetraspanins NET-6 and CD151 in breast cancer as a potential tumor biomarker

Tetraspanins have been implicated in multiple biological functions including protein networking and cell signaling. NET-6 (TSPAN 13) has been demonstrated to be a tumor suppressor gene in breast cancer, while CD151 is more likely to act as an oncogene. However, the biological function of both proteins is still inconclusive. Immunohistochemistry was used to analyze the expression of NET-6 and CD151 proteins in breast tumors and benign epithelial cells. The cellular expression of both markers was correlated with HER2, ER, and PR status as well as tumor grade, Ki-67 scores, invasion, and metastasis. Expression of NET-6 and CD151 was variable both in tumors and in benign epithelial cells. Expression of NET-6 and CD151 was stronger in tumors than in benign epithelial cells. The expression of NET-6 was also stronger in HER2-negative, low-grade, lymphovascular invasion-negative, and non-metastatic breast tumors. There was no correlation between NET-6 expression and ER, or PR, or triple-negative status. There was no correlation between CD151 expression and HER2, ER, PR, or triple-negative status, tumor grade, or Ki-67 scores, invasion, and metastasis. The expression of tetraspanins NET-6 and CD151 may indicate an alteration of their biological function during neoplastic transformation. NET-6 expression in tumors might be a potential marker indicating the outcome of breast cancer.

Integrin-independent support of cancer drug resistance by tetraspanin CD151

Tetraspanin protein CD151 has typically been studied as binding partner and functional regulator of laminin-binding integrins. However, we show here that CD151 supports anti-cancer drug resistance independent of integrins. CD151 ablation sensitized multiple tumor cell types to several anti-cancer drugs (e.g., gefitinib and camptothecin), thus increasing apoptosis, as seen using cleaved caspase-3, cleaved PARP (poly (ADP-ribose) polymerase), annexin V, and propidium iodide staining assays. Drug sensitization due to CD151 ablation is integrin-independent, because, (1) effects occurred in cells when integrins were unengaged with ligand, (2) integrin ablation (α3 and α6 subunits) did not mimic effects of CD151 ablation, (3) the CD151^QRD mutant, with diminished integrin association, and CD151^WT (unmutated CD151) similarly reconstituted drug protection, and (4) treatment with anti-cancer drugs selectively upregulated intracellular nonintegrin-associated CD151 (NIA-CD151), consistent with its role in drug resistance. Together, these results suggest that upregulated CD151 expression may support not only typical integrin-dependent functions, but also integrin-independent survival of circulating (and possibly metastatic) cancer cells during anti-cancer drug therapy.

CD151 promotes proliferation and migration of SK-NEP-1 cells via the GSK-3β/P21/cyclinD signaling pathway

Wilms'tumor is the most common malignant tumor with a poor clinical prognosis because of metastasis or recurrence among children worldwide. CD151, a member of transmembrane 4 superfamily, has now been confirmed to be involved in tumor progression including the proliferation, migration, invasion and metastasis of tumor cells. GSK-3β/P21/cyclinD signaling pathway plays a critical role in the cell cycle progression, regulating cellular proliferation. In this study, CD151 protein and mRNA levels were examined by western blot and RT-PCR. The proliferation of SK-NEP-1 cells was examined by CCK8 assay and the migration of SK-NEP-1 cells was detected with wound healing assay. Furthermore, p-GSK3β protein, GSK3β protein, p21protein and CyclinD protein were examined by western blot to verify whether CD151 could regulate the Wilms'tumor progression via the GSK-3β/P21/cyclinD signaling pathway. The RT-PCR and western blot results showed that CD151 protein was upregulated in Wilms'tumor cells compared with the control. The results by CCK8 assay and wound healing assay demonstrated that CD151 overexpression promoted the proliferation and migration in SK-NEP-1 cells and CD151 interference showed the opposite effects. Western blot assay revealed that CD151 activated the GSK-3β/P21/cyclinD signaling pathway and upregulated the expression of p-GSK3β protein, p21protein and CyclinD protein. It was also verified that CD151 promotes proliferation and migration of SK-NEP-1 cells through the GSK-3β/P21/cyclinD signaling pathway in this study. The specific aim of the study is to investigate and verify the role of CD151 in Wilm's tumor. Therefore, in-depth study on the molecular mechanisms will provide new strategies and methods for the treatment of Wilm's tumor.

CD151 regulates expression of FGFR2 in breast cancer cells via PKC-dependent pathways

Expression of the tetraspanin CD151 is frequently upregulated in epithelial malignancies and correlates with poor prognosis. Here, we report that CD151 is involved in regulation of the expression of fibroblast growth factor receptor 2 (FGFR2). Depletion of CD151 in breast cancer cells resulted in an increased level of FGFR2. Accordingly, an inverse correlation between CD151 and FGFR2 was observed in breast cancer tissues. CD151-dependent regulation of the FGFR2 expression relies on post-transcriptional mechanisms involving HuR (also known as ELAVL1), a multifunctional RNA-binding protein, and the assembly of processing bodies (P-bodies). Depletion of CD151 correlated with inhibition of PKC, a well-established downstream target of CD151. Accordingly, the levels of dialcylglycerol species were decreased in CD151-negative cells, and inhibition of PKC resulted in the increased expression of FGFR2. Whereas expression of FGFR2 itself did not correlate with any of the clinicopathological data, we found that FGFR2-/CD151+ patients were more likely to have developed lymph node metastasis. Conversely, FGFR2-/CD151- patients demonstrated better overall survival. These results illustrate functional interdependency between CD151 complexes and FGFR2, and suggest a previously unsuspected role of CD151 in breast tumorigenesis.

Prognostic Value of RNASEH2A-, CDK1-, and CD151-Related Pathway Gene Profiling for Kidney Cancers

The nucleotide degrading enzyme gene RNASEH2A (ribonuclease H2 subunit A) has been found to be overexpressed in cancers. Our aim was to understand the role of RNASEH2A in cancer prognostication and to establish a scoring system based on the expressions of genes interacting with RNASEH2A. We screened the nucleotide degrading enzyme gene expression in RNAseq data of 14 cancer types derived from The Cancer Genome Atlas (TCGA) and found that RNASEH2A overexpression was associated with poor patient survival only in renal cell carcinomas (RCCs). Further cluster analyses of samples with poor outcomes revealed that cluster of differentiation 151 (CD151) upregulation correlated with low cyclin dependent kinase 1 (CDK1) and high RNASEH2A expression. The combination of low CD151 expression and high RNASEH2A expression resulted in impaired proliferation in four kidney cancer cell lines, suggesting potential synthetic dosage lethality (SDL) interactions between the two genes. A prognostication scoring system was established based on the expression levels of RNASEH2A-, CDK1-, and CD151-related genes, which could effectively predict the overall survival in a TCGA clear cell RCC cohort (n = 533, 995.3 versus 2242.2 days, p < 0.0001), in another clear cell renal cell carcinoma (ccRCC) cohort E-GEOD-22541 (n = 44, 390.0 versus 1889.2 days, p = 0.0007), and in a TCGA papillary RCC (pRCC) cohort (n = 287, 741.6 versus 1623.7 days, p < 0.0001). Our results provide a clinically applicable prognostication scoring system for renal cancers.

Exosomal tetraspanins as regulators of cancer progression and metastasis and novel diagnostic markers

Exosomes are cell-cell communicators emerging as a new paradigm for noninvasive diagnosis and prognosis of treatment response. Exosomal tetraspanin proteins like CD63, CD9 and CD81 play a critical role in sorting, selective recruitment of biomolecules, target selection, cell-specific entry, capturing, angiogenesis and vasculogenesis. These tetraspanins are being used as markers for oral, colorectal and colon cancers and glioblastoma. However, exosomal markers with robust specificity for early detection of carcinomas are the furthest along. EXO CARTA database shows the presence of CD151 in exosomes of colorectal, melanoma, ovarian and prostate cancers. CD151 preferentially targets exosomes to lung, lymph node and stroma cells. The present review discussed the possible role of tetraspanins in the formation, cargo selection, target selection and uptake of exosomes and suggests exciting new directions for future research.

CD151 up-regulation contributes to the invasion of pituitary adenomas

CD151 is up-regulated in several types of tumors and is involved in tumor invasion and metastasis. However, the potential role of CD151 in pituitary adenomas remains unclear. Here, we performed quantitative real-time PCR and immunochemistry to measure the expression levels of CD151 in samples of pituitary adenomas and investigated the effects of CD151 knock-down on tumor phenotypes in the HP75 pituitary adenoma cell line. We found that, compared to normal pituitary tissues, CD151 expression is increased in non-invasive pituitary adenomas and further increased in invasive pituitary adenomas. CD151 knock-down inhibited cell proliferation, invasion, clone formation, in vivo tumor development, and promoted apoptosis in the pituitary adenoma cell line. Our results fully support that CD151 plays an important role in promoting invasion and aggression of pituitary adenomas and thus might be a therapeutic target.

Tetraspanin CD151 as an emerging potential poor prognostic factor across solid tumors: a systematic review and meta-analysis

Tetraspanin CD151, also known as PETA-3 or SFA-1, has been reported to predict prognosis in various solid tumors. Yet, the results of these studies remained inconclusive. Here, we performed this meta-analysis of relevant studies published on the topic to quantitatively evaluate the clinicopathological significance of CD151 in solid tumors. The relevant articles were identified via searching the PubMed, Web of Science and Embase database. The pooled hazard ratios (HRs) and corresponding 95% confidence intervals (CI) of overall survival (OS) and disease-free survival (DFS) were calculated to evaluate the prognostic value of CD151 expression in patients with solid tumors. A total of 19 studies involving 4, 270 participants were included in the study, we drew the conclusion that CD151 overexpression was associated with statistically significant poor OS (pooled HR = 1.498, 95% CI = 1.346-1.667, P<0.001) and poor DFS (pooled HR = 1.488, 95% CI = 1.314-1.685, P<0.001). Furthermore, the subgroup analysis revealed that the associations between CD151 overexpression and the outcome endpoints (OS or TTP) were significant within the Asian region and European, as well in patients with breast cancer or gastric cancer. Taken together, the incorporative HR showed CD151 overexpression was associated with poor survival in human solid tumors. CD151 could be a valuable prognosis biomarker or a potential therapeutic target of solid tumors.

CD151-mediated adhesion is crucial to osteosarcoma pulmonary metastasis

CD151, a tetraspanin family protein involved in cell-cell and cell-extracellular matrix interaction, is differentially expressed in osteosarcoma cell membranes. Thus, this study aimed to investigate the role of CD151 in osteosarcoma metastasis. We analyzed CD151 expression in patient tissue samples using immunohistochemistry. CD151 expression was also silenced with shRNA in osteosarcoma cells of high metastatic potential, and cell adhesion, migration and invasion were evaluated in vitro and pulmonary metastasis was investigated in vivo. Mediators of cell signaling pathways were also examined following suppression of CD151 expression. Overall survival for patients with low versus high CD151 expression level was 94 vs. 41 months (p=0.0451). CD151 expression in osteosarcoma cells with high metastatic potential was significantly higher than in those with low metastatic potential (p<0.001). shRNA-mediated silencing of CD151 did not influence cell viability or proliferation; however, cell adhesion, migration and invasion were all inhibited (all p<0.001). In mice inoculated with shRNA-transduced osteosarcoma cells, the number and size of lung metastatic lesions were reduced compared to the mice inoculated with control-shRNA transduced cells (p<0.001). In addition, CD151 knockdown significantly reduced Akt, p38, and p65 phosphorylation as well as focal adhesion kinase, integrin β1, p70s6, and p-mTOR levels. Taken together, CD151 induced osteosarcoma metastasis likely by regulating cell function through adhesion signaling. Further studies are necessary to fully explore the diagnostic and prognostic value of determining CD151 expression in osteosarcoma patients.

MiR-124 aggravates failing hearts by suppressing CD151-facilitated angiogenesis in heart

Heart failure (HF) is the final common pathway of various cardiovascular diseases. Although it is well documented that reduction of cardiac angiogenesis contributes to the progression from adaptive cardiac hypertrophy to HF, the molecular mechanisms remain unknown. In the present study, we found that cardiac expression of miR-124 was increased in patients and mice with HF. Recombinant adeno-associated virus (rAAV)-mediated miR-124 over-expression aggravated angiotensin II (Ang II) infusion-induced cardiac dysfunction and abnormal cardiac angiogenesis in mice. In vitro, transfection of miR-124 mimics significantly promoted apoptosis and reduced viability, migration, tube formation, and nitric oxide release in endothelial cells. In addition, CD151 was identified as a direct target of miR-124. Endothelial cell injury caused by CD151 silencing was mimicked by miR-124 over-expression. Re-expression of CD151 attenuated miR-124-mediated suppression of cardiac angiogenesis and cardiac dysfunction in Ang II-treated mice. Our observations suggest that miR-124 is an important negative regulator of cardiac angiogenesis and cardiac function, likely by suppressing the expression of CD151 in heart cells. Modulation of miR-124 levels may provide new strategies and targets for HF therapy.

CD151 promotes cell metastasis via activating TGF-β1/Smad signaling in renal cell carcinoma

Tetraspanin CD151 has been identified as a tumor promoter, which is upregulated in various malignant cell types. However, the function of CD151 and its underlying mechanism in renal cell carcinoma is still unknown. In this study, we detected the expression of CD151 in RCC cells and tissues and explored its regulatory mechanism. We found that CD151 was upregulated in renal cell carcinoma tissues and cells and its expression was significantly associated with tumor stage (p=0.019) and survival (p=0.001) by analyzing tissue microarrays. After silencing of CD151 via lentivirus vector in Caki-1 and Caki-2 cells, reduced ability of migration and invasion were detected with downregulation of CD151. The opposite results were observed in cells with CD151 overexpression. Furthermore, western blotting was performed to investigate the influence of CD151 on epithelial-to-mesenchymal transition, matrix metalloproteinase 9 and TGF-β1/Smad signaling pathway in RCC. Subsequently, upregulating the protein level of transforming growth factor-β1 in cells with silencing of CD151 could rescue the malignant behaviors inhibited, which indicated that CD151 may play its promoting role in RCC partially by stimulating the expression of TGF-β1. Conclusively, CD151 might exhibit a prominent role in migration and invasion of RCC cells via activating TGF-β1/Smad signaling pathway.

PIK3C2A mRNA functions as a miR-124 sponge to facilitate CD151 expression and enhance malignancy of hepatocellular carcinoma cells

Competing endogenous RNAs (ceRNAs) are RNA transcripts that can crosstalk with each other by competing for shared microRNAs (miRNAs) through miRNA response elements (MREs). Involved in ceRNA networks, the RNA transcripts may be in a balance, disruption of which could lead to tumorigenesis. Here we reveal a ceRNA interaction between PIK3C2A and CD151 mRNAs in hepatocellular carcinoma (HCC) cells. PIK3C2A is a candidate ceRNA of CD151 because mRNA 3' untranslated regions (3'UTRs) of these two genes contain miR-124 binding sites. miR-124 is downregulated, while PIK3C2A and CD151 are upregulated in HCC cells compared with normal hepatocytes. Direct and negative regulation of PIK3C2A and CD151 by miR-124 was confirmed in HCC cells. miR-124 and the two potential ceRNAs are all recruited to the RNA-induced silencing complex (RISC). In HCC cell lines QGY- 7703 and SMMC-7721, and normal hepatic cell line HL-7702, miR-124 plays a tumor suppressor role by targeting PIK3C2A and CD151. The MREs within PIK3C2A 3'UTR can independently stimulate CD151 expression level by acting as miR-124 decoys. PIK3C2A MREs enhance HCC cell malignancy by absorbing endogenous miR-124 and activating CD151 in HCC cells. We conclude that PIK3C2A 3'UTR functions as a trans activator to stimulate CD151 by competing for miR-124 binding in HCC cells. The collaboration of PIK3C2A and CD151 through ceRNA mechanism may be implicated in HCC initiation and development.

CD151, a novel host factor of nuclear export signaling in influenza virus infection

BACKGROUND

Despite advances in our understanding of the mechanisms of influenza A virus (IAV) infection, the crucial virus-host interactions during the viral replication cycle still remain incomplete. Tetraspanin CD151 is highly expressed in the human respiratory tract, but its pathological role in IAV infection is unknown.

OBJECTIVES

We sought to characterize the functional role and mechanisms of action of CD151 in IAV infection of the upper and lower respiratory tracts with H1N1 and H3N2 strains.

METHODS

We used CD151-null mice in an in vivo model of IAV infection and clinical donor samples of in vitro-differentiated human nasal epithelial cells cultured at air-liquid interface.

RESULTS

As compared with wild-type infected mice, CD151-null infected mice exhibited a significant reduction in virus titer and improvement in survival that is associated with pronounced host antiviral response and inflammasome activation together with accelerated lung repair. Interestingly, we show that CD151 complexes newly synthesized viral proteins with host nuclear export proteins and stabilizes microtubule complexes, which are key processes necessary for the polarized trafficking of viral progeny to the host plasma membrane for assembly.

CONCLUSIONS

Our results provide new mechanistic insights into our understanding of IAV infection. We show that CD151 is a critical novel host factor of nuclear export signaling whereby the IAV nuclear export uses it to complement its own nuclear export proteins (a site not targeted by current therapy), making this regulation unique, and holds promise for the development of novel alternative/complementary strategies to reduce IAV severity.

Recessive mutation in tetraspanin CD151 causes Kindler syndrome-like epidermolysis bullosa with multi-systemic manifestations including nephropathy

Epidermolysis bullosa (EB) is caused by mutations in as many as 19 distinct genes. We have developed a next-generation sequencing (NGS) panel targeting genes known to be mutated in skin fragility disorders, including tetraspanin CD151 expressed in keratinocytes at the dermal-epidermal junction. The NGS panel was applied to a cohort of 92 consanguineous families of unknown subtype of EB. In one family, a homozygous donor splice site mutation in CD151 (NM_139029; c.351+2T>C) at the exon 5/intron 5 border was identified, and RT-PCR and whole transcriptome analysis by RNA-seq confirmed deletion of the entire exon 5 encoding 25 amino acids. Immunofluorescence of proband's skin and Western blot of skin proteins with a monoclonal antibody revealed complete absence of CD151. Transmission electron microscopy showed intracellular disruption and cell-cell dysadhesion of keratinocytes in the lower epidermis. Clinical examination of the 33-year old proband, initially diagnosed as Kindler syndrome, revealed widespread blistering, particularly on pretibial areas, poikiloderma, nail dystrophy, loss of teeth, early onset alopecia, and esophageal webbing and strictures. The patient also had history of nephropathy with proteinuria. Collectively, the results suggest that biallelic loss-of-function mutations in CD151 underlie an autosomal recessive mechano-bullous disease with systemic features. Thus, CD151 should be considered as the 20th causative, EB-associated gene.

Long Noncoding RNA PVT1 Acts as a "Sponge" to Inhibit microRNA-152 in Gastric Cancer Cells

BACKGROUND

PVT1 was up-regulated in patients with gastric cancer (GC) and might be as a novel biomarker for predicting GC. However, the exact mechanism of PVT1 exerting functions in GC was still poorly understood. Emerging evidence suggests that long noncoding RNAs may act as endogenous microRNA (miRNA) sponges to bind to miRNAs and regulate their function.

AIM

This study aimed to determine the function of PVT1 on miR-152 expression in GC cells.

METHODS

The levels of PVT1 and miR-152 were determined in GC tissues by quantitative real-time PCR. The expression of miR-152 was detected in GC cells transfected with PVT1 plasmid or siPVT1. Luciferase assay was performed to verify the regulation of miR-152 to CD151 or FGF2 expression and PVT1 to miR-152 expression. The effects of PVT1 on the expression of CD151 and FGF2 were evaluated by Western blot.

RESULTS

PVT1 was up-regulated in GC tissues than that in the matched normal tissues, and mRNA level of miR-152 was decreased. MiR-152 was negatively associated with PVT1 expression in GC tissues. Based on the in silico analysis, we found that PVT1 have three binding sequences for miR-152. Moreover, PVT1 might inhibit the expression of miR-152 and increased the expression of CD151 and FGF2 through regulating miR-152. PVT1 was positively associated with CD151 and FGF2 expression in GC tissues.

CONCLUSIONS

PVT1 might act as a "sponge" to inhibit miR-152 in gastric cancer cells. PVT1 is a promising molecular target to improve the diagnosis and therapy of GC.

LAMC1 mRNA promotes malignancy of hepatocellular carcinoma cells by competing for MicroRNA-124 binding with CD151

Specific RNAs can function as sinks for endogenous miRNAs, known as competing endogenous RNAs (ceRNAs). Here, we confirm a miR-124 mediated ceRNA crosstalk between LAMC1 and CD151 in hepatocellular carcinoma (HCC). miR-124 negatively regulates LAMC1 expression through two miRNA binding sites within its 3' untranslated region (3'UTR) and suppresses migration and invasion of HCC cells through regulating LAMC1. The wild type LAMC1 miRNA response elements (MREs) facilitate expression of CD151, and this regulation is miR-124 dependent. In clinical hepatic tissues, LAMC1 and CD151 mRNAs exhibit positive correlation. Importantly, LAMC1 MREs promote HCC malignancy by absorbing miR-124 and by assisting CD151 expression. We conclude that LAMC1 mRNA acts as a trans regulator to stimulate CD151 expression by competing for miR-124 binding in HCC cells. © 2017 IUBMB Life, 69(8):595-605, 2017.