Motility-related protein-1 (MRP-1/CD9) expression can predict disease-free survival in patients with squamous cell carcinoma of the head and neck

TSPAN1, a novel tetraspanin member highly involved in carcinogenesis and chemoresistance

The tetraspanin (TSPAN) family constitutes a poorly explored family of membrane receptors involved in various physiological processes, with relevant roles in anchoring multiple proteins, acting as scaffolding proteins, and cell signaling. Recent studies have increasingly demonstrated the involvement of TSPANs in cancer. In particular, tetraspanin 1 (also known as TSPAN1, NET-1, TM4C, C4.8 or GEF) has been implicated in cell survival, proliferation and invasion. Recently, our laboratory revealed a key role of TSPAN1 in the acquired resistance of tumor cells to conventional chemotherapy (e.g., cisplatin). In this review, we summarize and discuss the latest research on the physiological mechanisms of TSPANs in cancer and, in particular, on TSPAN1 regulating resistance to chemotherapy. A model of TSPAN1 action is proposed, and the potential of targeting TSPAN1 in anticancer therapeutic strategies is discussed.

Prognostic Value of CD9 in Solid Tumor: A Systematic Review and Meta-Analysis

Numerous clinical studies investigated how low expression of CD9 predicts poor prognosis of solid tumor. However, the results were inconclusive. This present meta-analysis was therefore performed to determine the prognostic value of CD9 expression in solid tumors. In this meta-analysis, 25 studies involving 5,555 participants were included; the result showed strong significant associations between declined expression of CD9 and all endpoints: overall survival (OS) (hazard ratio (HR) = 1.88, 95% CI = 1.45-2.43, p < 0.000) and time to progression (TTP) (HR = 2.0, 95% CI = 1.38-2.88, p < 0.000). The subgroup analysis was also performed, which revealed that the associations between CD9 downregulated expression related to poor OS in lung cancer and head and neck cancer. Also, low expression of CD9 was significantly connected with poor TTP in patients with head and neck cancer. The adverse prognostic impact of decreased expression of CD9 was observed in patients of different ethnicities. In conclusion, these results showed that declined expression of CD9 was associated with poor survival in human solid tumors. CD9 may be a valuable prognostic predictive biomarker and a potential therapeutic target in human solid tumors.

Increased CD9 expression predicts favorable prognosis in human cancers: a systematic review and meta-analysis

Background

CD9 is implicated in cancer progression and metastasis by its role in suppressing cancer cell proliferation and survival. However, the prognostic and clinicopathological significance of CD9 expression is controversial. Therefore, the current meta-analysis was conducted to determine the prognostic and clinicopathological significance of CD9 expression in cancer patients.

Methods

Eligible studies were selected through database search of PubMed, Embase and Cochrane library up to April 5 2020. The necessary data were extracted from the included studies. Pooled hazard ratio (HR) and odds ratio (OR) with 95% confidence interval (CI) were calculated to evaluate the prognostic and clinicopathological significance of CD9 expression in cancer patients.

Results

A total of 17 studies consisting of 3456 cancer patients were included in this meta-analysis. An increased CD9 expression was significantly associated with a more favorable overall survival (OS) (HR 0.47, 95% CI 0.31–0.73, p = 0.001) and disease-free survival (DFS) (HR 0.48, 95% CI 0.30–0.79, p = 0.003). In subgroup analysis of cancer type, an increased CD9 expression was associated with increased OS in breast cancer and digestive system cancer, and with increased DFS in head and neck cancer and leukemia/lymphoma. Additionally, an increased CD9 expression significantly correlated with lower overall stage (OR 0.45, 95% CI 0.29–0.72, p = 0.001).

Conclusion

An increased CD9 expression was associated with favorable survival in cancer patients suggesting that CD9 expression could be a valuable survival factor in cancer patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02152-y.

CD9, a tetraspanin target for cancer therapy?

In the present minireview, we intend to provide a brief history of the field of CD9 involvement in oncogenesis and in the metastatic process of cancer, considering its potential value as a tumor-associated antigenic target. Over the years, CD9 has been identified as a favorable prognostic marker or predictor of metastatic potential depending on the cancer type. To understand its implications in cancer beside its use as an antigenic biomarker, it is essential to know its physiological functions, including its molecular partners in a given cell system. Moreover, the discovery that CD9 is one of the most specific and broadly expressed markers of extracellular membrane vesicles, nanometer-sized entities that are released into extracellular space and various physiological body fluids and play a role in intercellular communication under physiological and pathological conditions, notably the establishment of cancer metastases, has added a new dimension to our knowledge of CD9 function in cancer. Here, we will discuss these issues as well as the possible cancer therapeutic implications of CD9, their limitations, and pitfalls.

Tetraspanins as regulators of the tumour microenvironment: implications for metastasis and therapeutic strategies

One of the hallmarks of cancer is the ability to activate invasion and metastasis. Cancer morbidity and mortality are largely related to the spread of the primary, localized tumour to adjacent and distant sites. Appropriate management and treatment decisions based on predicting metastatic disease at the time of diagnosis is thus crucial, which supports better understanding of the metastatic process. There are components of metastasis that are common to all primary tumours: dissociation from the primary tumour mass, reorganization/remodelling of extracellular matrix, cell migration, recognition and movement through endothelial cells and the vascular circulation and lodgement and proliferation within ectopic stroma. One of the key and initial events is the increased ability of cancer cells to move, escaping the regulation of normal physiological control. The cellular cytoskeleton plays an important role in cancer cell motility and active cytoskeletal rearrangement can result in metastatic disease. This active change in cytoskeletal dynamics results in manipulation of plasma membrane and cellular balance between cellular adhesion and motility which in turn determines cancer cell movement. Members of the tetraspanin family of proteins play important roles in regulation of cancer cell migration and cancer-endothelial cell interactions, which are critical for cancer invasion and metastasis. Their involvements in active cytoskeletal dynamics, cancer metastasis and potential clinical application will be discussed in this review. In particular, the tetraspanin member, CD151, is highlighted for its major role in cancer invasion and metastasis.

LINKED ARTICLES

This article is part of a themed section on Cytoskeleton, Extracellular Matrix, Cell Migration, Wound Healing and Related Topics. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-24.

Osteopontin promotes the invasive growth of melanoma cells by activating integrin αvβ3 and down-regulating tetraspanin CD9

Overexpression of osteopontin (OPN) is strongly associated with the invasiveness/metastasis of many cancers, including melanomas. However, the molecular mechanisms of OPN in these processes remain poorly understood. We found that forced expression of OPN in early vertical-growth-phase melanoma cells dramatically increased their migration/invasion and growth/survival in a three-dimensional collagen I gel. Neutralizing antibodies to OPN, integrin β1, and integrin αvβ3, but not to CD44, negated the effects of OPN. Conversely, knocking down OPN in metastatic melanoma cells abrogated the invasive growth. OPN overexpression activated and OPN knockdown inactivated αvβ3 and αvβ5 integrins, negligibly affecting their expression. We further found OPN expression to inversely correlate with tetraspanin CD9 expression. Early-stage melanoma cells displayed low OPN and high CD9 expression, and conversely, metastatic cells displayed high OPN and low CD9 expression. Overexpression of OPN in vertical-growth-phase melanoma cells induced down-regulation of CD9, and knockdown of OPN in metastatic melanoma cells up-regulated CD9. Reversion of these CD9 changes abolished the effects of OPN. Furthermore, knockdown of CD9 in early-stage melanoma cells stimulated their invasive capacity in three-dimensional collagen. Similarly, microarray analyses of benign nevi and primary melanomas from different stages revealed an inverse correlation between OPN and CD9. These data suggest that OPN promotes melanoma cell invasion by activating integrin αvβ3 and down-regulating CD9, a putative metastasis suppressor.

Tetraspanins CD9 and CD151, epidermal growth factor receptor and cyclooxygenase-2 expression predict malignant progression in oral epithelial dysplasia

Background:

Prognostic biomarkers aim to improve on the current inadequate method of histological assessment to identify patients with oral epithelial dysplasia at greatest risk of malignant transformation. We aimed to assess the prognostic ability of six protein biomarkers linked to the epidermal growth factor receptor (EGFR) pathway, including three tetraspanins, in a large multicentre oral dysplasia cohort.

Methods:

One hundred and forty-eight cases with varying degrees of epithelial dysplasia underwent immunohistochemical assessment for CD9, CD151, CD82, EGFR, Her-2, and COX-2. Scoring was performed independently by two observers. Univariate analyses using both logistic and Cox regression models and a multivariate regression were performed.

Results:

Malignant progression was significantly greater in those cases with decreased expression of CD9 (P=0.02), and increased expression of CD151 (P=0.02), EGFR (P=0.04), and COX-2 (P=0.003). Histological grade (P=0.0002) and morphology (P=0.03) were also prognostic, whereas smoking and alcohol were not. The optimal combination by backward-variable selection was of histological grade (hazard ratio (HR) 1.64; 95% CI 1.12, 2.40), COX-2 overexpression (HR 1.12; 1.02, 1.24) and CD9 underexpression (HR 0.88; 0.80, 0.97). CD82 and Her-2 demonstrated no prognostic ability.

Conclusion:

This is the first study of the expression and prognostic potential of the tetraspanins in oral dysplasia. A combination of certain biomarkers with clinical factors appeared to improve the accuracy of determining the risk of malignancy in individuals with oral dysplasia. These findings may also offer potential new therapeutic approaches for this condition.

Knockout of the tetraspanin Cd9 in the TRAMP model of de novo prostate cancer increases spontaneous metastases in an organ-specific manner

Prostate cancer is an extremely heterogeneous disease; patients that do progress to late-stage metastatic prostate cancer have limited treatment options, mostly palliative. Molecules involved in the metastatic cascade may prove beneficial in stratifying patients to assign appropriate treatment modalities and may also prove to be therapeutic antimetastatic targets. The tetraspanin group of molecules are integral membrane proteins that associate with motility-related proteins such as integrins. Clinical studies have mostly shown that reduced expression levels of the tetraspanin CD9 are correlated with tumour progression in a range of cancers. Furthermore, functional studies have shown CD9 to be involved in cell motility and adhesion and that it may influence metastasis. The effects of endogenous CD9 on prostate cancer initiation and progression were analysed by crossing a Cd9-/- (KO) murine model with a model of de novo developing and spontaneously metastasising prostate cancer, namely the transgenic adenocarcinoma of mouse prostate model. Our study demonstrates for the first time that ablation of Cd9 had no detectable effect on de novo primary tumour onset, but did significantly increase metastasis to the liver but not the lungs.

[Relationship among the expression of lymphatic vessel density, microvessel density, carcinoembryonic antigenic mRNA, KAI1, and Kiss-1, and prognosis in patients with non-small cell lung cancer]

背景与目的

目前对非小细胞肺癌（non-small cell lung cancer, NSCLC）患者预后的研究很多，有些临床病理因素已被公认与预后有关，本研究旨在对淋巴管密度（lymphatic vessel density, LVD）、微血管密度（microvessel density, MVD）及癌胚抗原信使核糖核酸（carcinoembryonic antigen messenger ribonucleic acid, CEAmRNA）和肿瘤转移抑制基因KAI1、Kiss-1的表达与NSCLC患者预后的关系进行探讨。

方法

选取57例NSCLC患者，采用逆转录巢式聚合酶链反应（nested-RT-PCR）和微流控芯片（micro-fluid chip）技术对外周血CEAmRNA的表达进行检测；采用免疫组织化学技术对肺癌组织LVD、MVD和KAI1、Kiss-1的表达进行检测，并对所有患者进行随访分析。

结果

全组的5年生存率为18%，中位生存期为34个月；单因素分析显示TNM分期、淋巴结有无转移、CEAmRNA的阳性表达、MVD、LVD和Kiss-1的表达对生存有影响；多因素分析显示TNM分期、淋巴结有无转移和CEAmRNA的表达是影响预后的独立危险因素。

结论

在NSCLC患者中MVD、LVD和Kiss-1及CEAmRNA的表达可以在一定程度上反映患者的预后。

Prognostic significance of CD9 expression in locally advanced gastric cancer treated with surgery and adjuvant chemoradiotherapy

The tetraspanin transmembrane protein CD9 plays an important role in inhibiting cell motility in numerous neoplastic cell lines, including lung, gastric, pancreatic, and bladder carcinomas. The prognostic importance of CD9 in the survival of gastric carcinoma patients has not been examined to date, and in the present study, we attempted to define its prognostic value. The study included 49 (35 men and 14 women) patients with locally advanced (stages II-IV) gastric cancer. The median age was 55 years (range, 22-73 years). Surgery was the initial treatment for all patients, followed by adjuvant chemoradiotherapy. Tissue sections were evaluated immunohistochemically with a monoclonal anti-CD9 antibody. Of the 49 patients with gastric adenocarcinoma, 11 (22.4%) were CD9-positive, and 38 (77.6%) were CD9-negative. A significant prognostic value in disease-free survival and overall survival was observed in T classification and CD9 positivity. In conclusion, CD9 expression in gastric cancer appears to be associated with poor prognosis.

Differential expression of tetraspanin CD9 in basal cell and squamous cell carcinomas of the skin and actinic keratosis

Tetraspanins are potentially useful molecular markers that differentiate between tumour classes and subtypes, since members of this protein family were often found to be altered during malignant conversion and tumour progression. In this study, we analysed expression of the tetraspanin CD9 in the frequent cutaneous neoplasms basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and actinic keratosis (AK), which is considered a precursor lesion (carcinoma in situ) from which an invasive SCC can develop. A moderate to strong CD9-specific staining of the tumour cells' plasma membranes was uniquely observed in all BCCs, SCCs and AKs. All SCCs showed additional intracellular CD9 which was rarely (20%) seen in AKs. Semi-quantitative assessment of CD9 present in the plasma membranes of tumour cells of BCCs (mean staining intensity 1.91) and SCCs (3.64) reflected the different CD9 expression of normal precursor cells from which these tumours most likely originate. Although considered an intermediate stage in the development of SCCs, AKs did not show intense staining of the plasma membranes typical of normal keratinocytes or invasive SCCs (p=0.011) but only moderate intensity (mean 1.63). In BCCs, significantly (p=0.0005, n=56) stronger CD9-specific immunoreactivity was seen in the inner regions of the tumours than at their sites of expansion. In summary, our results point to an important role of CD9 at the front of tumour expansion in BCCs and SCCs, and in the pathogenesis of invasive SCCs.

Role of CD9 in proliferation and proangiogenic action of human adipose-derived mesenchymal stem cells

CD9 belongs to the tetraspanin family and is involved in cell motility, osteoclastogenesis, metastasis, neurite outgrowth, myotube formation, and sperm-egg fusion. CD9 also promotes juxtacrine signaling involved in proliferation and attachment. Varying degrees of CD9 expression have been found in human mesenchymal stem cells. In this study, we determined the functional roles of CD9 in human adipose-derived mesenchymal stem cells (hASCs). The CD9 expression in hASCs was down-regulated during culture expansion. A colony-forming unit assay revealed that the clonal expandability of hASCs was directly correlated with the CD9 expression level of the colony. The CD9(high) cells exhibited an increased ability to proliferate, increased cell adhesiveness, and better in vitro tube formation than the CD9(low) cells. The cellular proliferation and attachment of the CD9(high) cells were inhibited upon treatment with a blocking antibody against CD9 and the transduction of a CD9 miRNA lentivirus. The CD9(high) cells showed higher NF-kappaB promoter activity and higher levels of intercellular adhesion molecule 1 than the CD9(low) cells. Reverse transcription-polymerase chain reaction analysis revealed higher endothelial nitric oxide synthase expression in the CD9(high) cells than in the CD9(low) cells. The engraftment and the proangiogenic action of hASCs in a murine model of hindlimb ischemia were significantly higher in the CD9(high) cells than in the CD9(low) cells. This study indicates that CD9 plays roles in cell proliferation and attachment in vitro as well as in in vivo engraftment and that it can be considered as a useful marker to predict the in vivo efficacy of hASCs.

Contrasting effects of EWI proteins, integrins, and protein palmitoylation on cell surface CD9 organization

CD9, a tetraspanin protein, makes crucial contributions to sperm egg fusion, other cellular fusions, epidermal growth factor receptor signaling, cell motility, and tumor suppression. Here we characterize a low affinity anti-CD9 antibody, C9BB, which binds preferentially to homoclustered CD9. Using mAb C9BB as a tool, we show that cell surface CD9 homoclustering is promoted by expression of alpha3beta1 and alpha6beta4 integrins and by palmitoylation of the CD9 and beta4 proteins. Conversely, CD9 is shifted toward heteroclusters upon expression of CD9 partner proteins (EWI-2 and EWI-F) or other tetraspanins, or upon ablation of CD9 palmitoylation. Furthermore, unpalmitoylated CD9 showed enhanced EWI-2 association, thereby demonstrating a previously unappreciated role for tetraspanin palmitoylation, and underscoring how depalmitoylation and EWI-2 association may collaborate to shift CD9 from homo- to heteroclusters. In conclusion, we have used a novel molecular probe (mAb C9BB) to demonstrate the existence of multiple types of CD9 complex on the cell surface. A shift from homo- to heteroclustered CD9 may be functionally significant because the latter was especially obvious on malignant epithelial tumor cells. Hence, because of its specialized properties, C9BB may be more useful than other anti-CD9 antibodies for monitoring CD9 during tumor progression.

Identification of molecular markers for metastasis-related genes in primary breast cancer cells

Comparing differential gene expression profiles established by cDNA microarray between normal cells (N), primary carcinoma cells (T), and metastatic carcinoma cells (M) may determine those critical genes directly associated with progression and metastasis of breast cancer. Total RNA was extracted by laser microdissection (LMD) from 20 slices of T, N and M from 6 cases. After amplification by a T7-based system, differentially expressed genes between T, N and M were identified by cDNA microarray. In addition, to clarify the mechanism for altered gene expression, we determined the methylation status by sequencing after bisulfite treatment for intriguing genes. As a result, the expression of motility related protein-1 (MRP-1/CD9), peripheral myelin protein-22 (PMP-22), and caspase 3 (CASP-3) were down-regulated in M compared to T. We focused especially on MRP-1 and found that the expression status of MRP-1 was significantly inversely associated with stage of disease in 56 cases of breast cancer (P<0.05), and the relapse free survival in 5 years was significantly higher in MRP-1 positive cases than those negative cases (P<0.05). Conversely, overexpression, by 11-fold, of signal transduction and translation factors were observed in T compared to N. The cancer specific methylation was observed only in CASP-3 in a case. In conclusion, the establishment of the present assay allows us to detect genes directly associated with each cell population within tumor tissue and gives us clues to identify metastasis-related genes comprehensively in clinical breast cancer cases.