Tetraspanin 1 Research Articles

TSPAN1 overexpression as an indicator of poor prognosis in estrogen receptor-positive breast cancer.

Tetraspanin 1 (TSPAN1) is a newly discovered protein of the tetrameric protein family encoded by the TSPAN1 gene localized in the 1p34 chromosome region. TSPAN1 has been shown to be associated with various malignancies. In this study, we aimed to investigate the prognostic significance of TSPAN1 in breast cancer. Estrogen receptor-positive (ER+) breast cancer is the largest breast cancer subgroup, and ER-targeted therapies have significantly prolonged survival and improved symptoms in advanced breast cancer. TSPAN1 overexpression was found to be associated with a poor prognosis in ER+ breast cancer. We analyzed the expression of TSPAN1 in breast cancer tissues and cell lines using western blotting and quantitative reverse transcription polymerase chain reaction (RT-qPCR). TSPAN1 expression was higher in breast cancer cells as compared with normal breast tissue. There was a significant association between a high TSPAN1 level and a low survival rate. Inhibition of TSPAN1 significantly reduced the proliferation and invasion of BT474 cells both in vitro and in vivo. The downregulation of TSPAN1 in breast cancer cells significantly reduced the levels of p-mitogen-activated protein kinase 1 (MEK1) (S298) and p-extracellular signal-regulating kinase (ERK) 1/2. TSPAN1 modulates downstream extracellular matrix (ECM) receptor signaling cascades and promotes cellular proliferation and invasion in breast cancer. TSPAN1 inhibition may be a potential new treatment strategy for breast cancer.

Modeling of new markers for the diagnosis and prognosis of pancreatic cancer based on the transition from inflammation to cancer.

Pancreatic adenocarcinoma (PAAD) is a lethal disease with a poor prognosis. Genes involved in acute pancreatitis (AP) or chronic pancreatitis (CP) might be important for PAAD development. This study sought to identify potential PAAD diagnosis markers and to establish a PAAD prognosis prediction model based on AP- and CP-related genes. The significantly differentially expressed genes in both AP or CP and PAAD were obtained by a bioinformatics analysis. A risk-score model for predicting survival was constructed based on The Cancer Genome Atlas (TCGA) data and validated using an International Cancer Genome Consortium (ICGC) cohort. Protein expression and the effects of the genes in the risk models were validated by immunohistochemistry, or Cell Counting Kit-8 (CCK-8) and transwell assays. The study sample data included six AP tissue samples and five normal pancreatic tissue samples, six CP tissue samples and six normal pancreatic tissue samples from the Gene Expression Omnibus (GEO) expression profiling microarrays GSE109227 and GSE41418 data sets, respectively, and fragments per kilobase per million mapped fragments (FPKM) data from four normal controls and 150 PAAD cases from TCGA database, and 182 cancer patient samples with complete survival prognostic data from the ICGC database. In total, 508 significantly differentially expressed genes were found in both AP or CP and PAAD. Trefoil factor 2 (TFF2), tubulointerstitial nephritis antigen (TINAG), trefoil factor 1 (TFF1), aquaporin 5 (AQP5), SAM pointed domain containing ETS transcription factor (SPDEF), anterior gradient protein 2 (AGR2), apolipoprotein B messenger RNA editing enzyme catalytic subunit 1 (APOBEC1), kallikrein-related peptidase 6 (KLK6), dopa decarboxylase (DDC), mucin 13 (MUC13), claudin 18 (CLDN18), annexin A10 (ANXA10), and tetraspanin 1 (TSPAN1) were found to be present in PAAD and had the largest fold change. A risk-score model, comprising 19 genes, was constructed for prognostic prediction. A high-risk score indicated a poor prognosis. TINAG, DDC, SPDEF, and APOBEC1 proteins were increased in PAAD, while TINAG and DDC were correlated with the pathologic grade. Decreased TINAG, APOBEC1, transmembrane protein 94 (TMEM94), and kelch like family member 36 (KLHL36) expression inhibited PAAD cell proliferation, while decreased SPDEF, TMEM94, and KLHL36 expression significantly inhibited PAAD cell migration. The AP and CP co-related genes were significantly correlated with PAAD. TINAG, DDC, SPDEF, and APOBEC1 could serve as new PAAD predictors. The risk model developed in this study could be used to predict the prognosis of PAAD patients.

TSPAN1 inhibits metastasis of nasopharyngeal carcinoma via suppressing NF-kB signaling.

Nasopharyngeal carcinoma (NPC) originates in the epithelial cells of the nasopharynx and is a common malignant tumor in southern China and Southeast Asia. Metastasis of NPC remains the main cause of death for NPC patients even though the tumor is sensitive to radiotherapy and chemotherapy. Here, we found that the transmembrane protein tetraspanin1 (TSPAN1) potently inhibited the in vitro migration and invasion, as well as, the in vivo metastasis of NPC cells via interacting with the IKBB protein. In addition, TSPAN1 was essential in preventing the overactivation of the NF-kB pathway in TSPAN1 overexpressing NPC cells. Furthermore, reduced TSPAN1 expression was associated with NPC metastasis and the poor prognosis of NPC patients. These results uncovered the suppressive role of TSPAN1 against NF-kB signaling in NPC cells for preventing NPC metastasis. Its therapeutic value warrants further investigation.

Tetraspanin 1 regulates papillary thyroid tumor growth and metastasis through c-Myc-mediated glycolysis.

Papillary thyroid cancer (PTC) is the most common form of thyroid cancer and is characterized by its tendency for lymphatic metastasis, leading to a poor prognosis. Tetraspanin 1 (TSPAN1) is a member of the tetra-transmembrane protein superfamily and has been implicated in tumorigenesis and cancer metastasis in various studies. However, the role of TSPAN1 in PTC tumor development remains unclear. In this study, we aimed to investigate the impact of TSPAN1 on PTC cell behavior. Our results demonstrate that knockdown of TSPAN1 inhibits PTC cell proliferation, migration, and invasion, while overexpression of TSPAN1 has the opposite effect. These findings suggest that TSPAN1 might play a role in the tumorigenesis and invasiveness of PTC. Mechanistically, we found that TSPAN1 activates the ERK pathway by increasing its phosphorylation, subsequently leading to upregulated expression of c-Myc. Additionally, we observed that TSPAN1-ERK-c-Myc axis activation promotes glycolytic activity in PTC cells, as evidenced by the upregulation of glycolytic genes such as LDHA. Taken together, our findings indicate that TSPAN1 acts as an oncogene in PTC by regulating glycolytic metabolism. This discovery highlights the potential of TSPAN1 as a promising therapeutic target for PTC treatment. Further research in this area could provide valuable insights into the development of targeted therapies for PTC patients.

The immunological characteristics of TSPAN1 expressing B cells in autoimmune hepatitis.

Tetraspanin proteins are closely related to the functional changes of B cells, including antigen presentation, production of cytokines, and transduction. We aim to explore the potential role of Tetraspanin 1 (TSPAN1) in the biological activities of B cells in AIH. Herein, this study found that numbers of cells expressing TSPAN1 were significantly increased in AIH patients compared to PBC, chronic hepatitis B, and healthy control (P < 0.0001). Moreover, there was a positive correlation between numbers of TSPAN1+ cells and AIH disease severity (P < 0.0001). Immunofluorescence staining further confirmed that TSPAN1 was primarily expressed on CD19+ B cells. Flow-cytometric analysis showed that TSPAN1+ B cells secreted more inflammatory cytokines and expressed higher level of CD86 than TSPAN1- B cells. Furthermore, compared with TSAPN1- cells, the expression of CXCR3 on TSPAN1+ cells was also higher. Meanwhile, CXCL10, the ligand of CXCR3, was significantly elevated in the liver of AIH (P < 0.01) and had positive correlation with the quantities of TSPAN1 (P < 0.05). Interestingly, the numbers of TSPAN1+ B cells were decreased in AIH patients after immunosuppressive therapy. TSPAN1+ B cells in the liver may promote the progression of AIH via secreting cytokines and presenting antigens. The chemotactic movement of TSPAN1+ B cells toward the liver of AIH was possibly due to CXCR3 - CXCL10 interaction.

Tetraspanin 1 (TSPAN1) promotes growth and transferation of breast cancer cells via mediating PI3K/Akt pathway

ABSTRACT The incidence and mortality of breast cancer rank first among all types of female tumors. To improve patients’ prognosis with advanced breast cancer, new and more effective targets still need to be explored and identified. Tetraspanin 1 (TSPAN1) is highly expressed in several cancers and affects the progression of these tumors. However, there are few studies focused on its role in breast cancer. Previous study showed that TSPAN1 promoted epithelial-mesenchymal transition (EMT) and metastasis, and whether TSPAN1 could promote breast cancer via regulating EMT needs further study. In this study, we found high TSPAN1 expression in breast cancer tumor samples and cell lines which was confirmed by bioinformation analysis. The ablation of TSPAN1 suppressed the growth, and motility of breast cancer cells. We further found that TSPAN1 affected the EMT and mediated the PI3K/Akt pathway in breast cancer cells. In addition, TSPAN1 depletion suppressed tumor growth of breast cancer in mice. In summary, we thought TSPAN1 suppressed growth and motility of breast cancer via mediating EMT and PI3K/AKT pathway, and could serve as a potential target for treatment of breast cancer.

Knockdown of LINC01123 inhibits cell viability, migration and invasion via miR-361-3p/TSPAN1 targeting in cervical cancer.

Cervical cancer (CC) is a type of gynecological malignancy that poses a significant threat to females. The aim of the present study was to examine the role of long intergenic non-protein coding RNA 1123 (LINC01123) and its underlying molecular mechanism in the development of CC. mRNA expression levels of LINC01123 and microRNA (miR)-361-3p in CC tissue samples and cell lines were evaluated using reverse transcription-quantitative PCR. Cell viability, migration and invasion were detected using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, wound healing and Transwell assays. Moreover, a xenograft tumor model was established for elucidating the influence of LINC01123 knockdown on tumor growth in vivo. A dual-luciferase reporter assay was used to confirm the association between LINC01123 and miR-361-3p, and miR-361-3p and tetraspanin 1 (TSPAN1). Western blot analysis was used to determine TSPAN1 protein expression. LINC01123 expression was upregulated and miR-361-3p expression was reduced in CC tissue samples and cell lines. Knockdown of LINC01123 inhibited cell viability, migration and invasion in vitro, and suppressed tumor growth in vivo. Furthermore, LINC01123 targeted miR-361-3p and negatively regulated miR-361-3p expression. Overexpression of miR-361-3p inhibited cell viability, migration and invasion in HeLa and CaSki cells. Additionally, miR-361-3p targeted TSPAN1 and negatively regulated TSPAN1 expression. Inhibition of miR-361-3p and overexpression of TSPAN1 reversed the effect of LINC01123 knockdown on cell proliferation, migration and invasion in HeLa cells. Knockdown of LINC01123 inhibited cell proliferation, migration and invasion via miR-361-3p/TSPAN1 regulation in CC, which may present an effective target for treatment of CC.

TSPAN1 silencing protects against cerulein‐induced pancreatic acinar cell injury via targeting AGR2

Acute pancreatitis (AP) is an inflammatory gastrointestinal disorder affecting the pancreas. Previous study reported that tetraspanin 1 (TSPAN1) expression was significantly upregulated in the pancreas of AP patients. However, the underlying molecular mechanism of TSPAN1 in the pathogenesis of AP remains unclear. Thus, the aim of the present study was to investigate the potential role of TSPAN1 in development of AP. RT-qPCR was carried out to quantify the relative mRNA levels of TSPAN1 and anterior gradient-2 (AGR2). The CCK-8 assay was used to detect the cell viability. The TUNEL assay was performed to visualize the apoptotic cells. Western blot was performed to determine the expressions of proteins related to endoplasmic reticulum (ER) stress and apoptosis. ELISA kits were adopted to detect the concentration of inflammatory cytokines including TNF-α and IL-6. Finally, immunoprecipitation (IP) was used to verify the interaction between TSPAN1 and AGR2. TSPAN1 was upregulated in serum of AP patients and AP cell models. TSPAN1 silencing promoted the cell proliferation and inhibited inflammatory response in cerulein-induced AR42J cells. Moreover, TSPAN1 induced endoplasmic reticulum stress by binding AGR2. Interestingly, the overexpression of AGR2 abolished the effects of TSPAN1 silencing on cell proliferation and inflammatory response in cerulein-induced AR42J cells. In summary, TSPAN1 silencing protects against cerulein-induced pancreatic acinar cell injury through inhibiting ER stress-mediated by AGR2. Hence, TSPAN1 may serve as a promising therapeutic target for AP treatment.

CD9-positive cells in the intermediate lobe migrate into the anterior lobe to supply endocrine cells.

The adenohypophysis is composed of the anterior and intermediate lobes (AL and IL), and secretes important hormones for growth, sexual development, metabolism, and reproduction. In the marginal cell layer (MCL) facing Rathke's cleft between the IL and AL, cluster of differentiation (CD) 9-, CD81-, S100β-, and SOX2-quadruple positive (CD9/CD81/S100β/SOX2-positive) cells in the adult IL are settled as tissue-resident stem/progenitor cells supplying hormone-producing cells to the AL. However, it is unclear how CD9/CD81/S100β/SOX2-positive cells in the IL-side MCL migrate into the AL across Rathke's cleft. In the present study, we performed chimeric pituitary tissue culture using S100β/GFP-transgenic rats and Wistar rats, and traced the footprint of S100β/GFP-expressing cells. We detected IL-side S100β/GFP-expressing cells in the AL tissue, demonstrating that these cells migrate from the IL to the AL. However, the cells failed to migrate in the opposite direction. Consistently, scanning electron microscopic analysis revealed well-developed cytoplasmic protrusions in the IL-side MCL, but not in the AL-side MCL, suggesting that IL-side CD9/CD81/S100β/SOX2-positive cells had higher migratory activity. We also searched for a specific marker for IL-side CD9/CD81/S100β/SOX2-positive cells and identified tetraspanin 1 (TSPAN1) from microarray analysis. Downregulation of Tspan1 by specific siRNA impaired cell migration and significantly reduced expression of snail family transcriptional repressor 2 (Slug), a marker of epithelial-mesenchymal transition (EMT). Therefore, CD9/CD81/S100β/SOX2-positive cells in the IL-side MCL can be stem/progenitor cells that provide stem/progenitor cells to the AL-side MCL via SLUG-mediated EMT and cell migration.

Tetraspanin 1 promotes endometriosis leading to ovarian clear cell carcinoma.

Ovarian clear cell carcinoma (OCCC) reportedly develops from endometriosis. However, the molecular mechanism underlying its malignant progression to OCCC remains elusive. This study aimed to identify an essential gene in the malignant transformation of endometriosis to OCCC. We performed RNA sequencing in formalin‐fixed, paraffin‐embedded (FFPE) tissues of endometriosis (n = 9), atypical endometriosis (AtyEm) (n = 18), adjacent endometriosis to OCCC (AdjEm) (n = 7), and OCCC (n = 17). We found that tetraspanin 1 (TSPAN1) mRNA level was significantly increased by 2.4‐ (DESeq2) and 3.4‐fold (edgeR) in AtyEm and by 80.7‐ (DESeq2) and 101‐fold (edgeR) in OCCC relative to endometriosis. We confirmed that TSPAN1 protein level was similarly overexpressed in OCCC tissues and cell lines. In immortalized endometriosis cell lines, TSPAN1 overexpression enhanced cell growth and invasion. Mechanistically, TSPAN1 triggered AMP‐activated protein kinase (AMPK) activity, promoting endometriosis and cell growth. Upregulated levels of TSPAN1 are considered an early event in the development of high‐risk endometriosis that could progress to ovarian cancer. Our study suggests the potential of TSPAN1 as a screening candidate for high‐risk endometriosis.

Cancer-associated protein Tetraspanin1 increases cell growth through AMPK in atypical endometriosis

Objective: Tetraspanin1 (TSPAN1), a member of transmembrane 4 superfamilies, has been demonstrated to be important in cell invasion and metastasis in various types of cancers. However, the role of TSPAN1 in clear cell ovarian cancer has not been fully elucidated. The aim of the present study was to determine the functions of TSPAN1 in progression of endometriosis to clear cell ovarian cancer.

Delivery of TSPAN1 siRNA by Novel Th17 Targeted Cationic Liposomes for Gastric Cancer Intervention

Several studies focus on the relationship between immune cells in the tumor microenvironment and tumor cells. Th17 cells, a naïve CD4+ T cell subtype, secrete IL-17 cytokines that further the progression and metastasis of tumors, such as gastric cancer, which is a leading cause of cancer-related death worldwide. Moreover, previous studies have demonstrated that the polarization ratio of CD4+ T cells to Th17 cells is closely related to the Tetraspanin 1 (TSPAN1) protein. Therefore, in this study, we designed a novel Th17 antibody-modified liposome polycation-DNA complex (LPD) encapsulated with TSPAN1 small interfering RNA (siRNA) (Th17-LPDT), to decrease the polarization of CD4+ T cells, and thereby inhibit the development of gastric cancer. Our in vitro results demonstrated the decrease in CD4+ T cells polarization to Th17 cells follwing Th17-LPDT treatment. Furthermore, in vivo data proved that Th17-LPDT treatment significantly inhibits the formation of gastric tumors. We believe that Th17-LPDT is a promising targeted nanoparticle drug for the clinical treatment of gastric cancer and this study provides a new strategy for tumor intervention.

Detection of circulating tumor cells in blood of pancreatic ductal adenocarcinoma patients.

Aim: Previous studies suggest that circulating tumor cells (CTC) are present at very low frequencies in blood of pancreatic cancer (PC) patients. However, no technique has proven efficient for their detection, in part due to the lack of accurate tumor markers. Here, we evaluated the potential utility of two marker candidates - Mucin 16 (MUC16) and Tetraspanin 1 (TSPAN1) - identified through a detailed review of the literature.Methods: To evaluate the pattern of expression of both markers in pancreatic tumor cells vs. normal blood, we used cell lines derived from pancreatic cancer patients and blood from healthy adults.Results: Antibodies against both MUC16 and TSPAN1 showed expression in three pancreatic cancer (PC) cell lines while they were absent in blood cells. To evaluate the efficiency of isolating tumor cells from blood, PC cell lines were spiked at different frequencies in blood, sequentially stained with biotin-conjugated TSPAN1 and MUC16 antibodies and a streptavidin ferrofluids, followed by immunomagnetic enrichment. The recovery of spiked TSPAN1+ tumor cells was high with limited contamination by leukocytes. In contrast, no PC cells were isolated when the biotin MUC16 reagent was used because the biotin-conjugated clone did not recognize PC cells.Conclusion: The combination of MUC16, TSPAN1, and epithelial cell adhesion molecule (EpCAM) antibodies will likely increase the efficiency of capturing circulating tumor cell in blood of pancreatic ductal adenocarcinoma. To further develop a protocol for isolation of circulating tumor cell in blood of PC patients, high amounts of antibodies (5-10 mg) against EpCAM, MUC16, and TSPAN1 will be needed.

Tetraspanin 1 as a mediator of fibrosis inhibits EMT process and Smad2/3 and beta-catenin pathway in human pulmonary fibrosis.

Tetraspanin 1(TSPAN1) as a clinically relevant gene target in cancer has been studied, but there is no direct in vivo or vitro evidence for pulmonary fibrosis (PF). Using reanalysing Gene Expression Omnibus data, here, we show for the first time that TSPAN1 was markedly down‐regulated in lung tissue of patient with idiopathic PF (IPF) and verified the reduced protein expression of TSPAN1 in lung tissue samples of patient with IPF and bleomycin‐induced PF mice. The expression of TSPAN1 was decreased and associated with transforming growth factor‐β1 (TGF‐β1)‐induced molecular characteristics of epithelial‐to‐mesenchymal transition (EMT) in alveolar epithelial cells (AECs). Silencing TSPAN1 promoted cell migration, and the expression of alpha‐smooth muscle actin, vimentin and E‐cadherin in AECs with TGF‐β1 treatment, while exogenous TSPAN1 has the converse effects. Moreover, silencing TSPAN1 promotes the phosphorylation of Smad2/3 and stabilizes beta‐catenin protein, however, overexpressed TSPAN1 impeded TGF‐β1‐induced activation of Smad2/3 and beta‐catenin pathway in AECs. Together, our study implicates TSPAN1 as a key regulator in the process of EMT in AECs of IPF.

TSPAN1 upregulates MMP2 to promote pancreatic cancer cell migration and invasion via PLCγ.

Pancreatic cancer (PC), a malignancy of the digestive system, has one of the highest rates of metastasis and mortality. It is characterized by the detachment, migration, implantation and infiltration of tumor cells to form metastases or recurrent foci. Tetraspanin 1 (TSPAN1), a novel member of the TSPAN superfamily, is highly expressed in many types of cancer, including gastric, colon, liver and esophageal cancer. It has also been associated with lymph node metastasis, tumor recurrence and metastasis. However, the role of TSPAN1 in PC has not been fully elucidated. The aim of the present study was to determine the expression of TSPAN1 in human PC tissue samples and cell lines. Additionally, the functions of TSPAN1 in PC cell migration and invasion were assessed. The protein and gene expression of TSPAN1 was analyzed in clinical PC tissue samples and human PC cell lines (SW1990, BxPC3, Capan1 and PANC-1) via immunohistochemistry, reverse transcription-quantitative polymerase chain reaction and western blotting. The effect of TSPAN1 downregulation and overexpression in PC cells, via transfection with siRNA and pLNCX-TSPAN1-cDNA recombinant plasmid, respectively, on cell invasion and migration were assessed. Additionally, the mRNA expression of matrix metalloproteinase (MMP2) and MMP9 were determined. In clinical PC tissue samples, the expression of TSPAN1 was markedly increased when compared with normal pancreatic tissue samples. TSPAN1 was also highly expressed in PC cell lines compared with HPDE, a normal pancreatic cell line. Transfection with siRNA targeting TSPAN1 in PC cell lines significantly suppressed PC cell migration and invasion, and downregulated the expression of MMP2. However, there was no effect on MMP9. Consistently, PC cell migration and invasion together with MMP2 mRNA expression were markedly increased following TSPAN1 ectopic overexpression. The present study utilized small interfering RNAs (siRNA) targeted to phospholipase Cγ (PLCγ) to demonstrate that TSPAN1 siRNA suppressed PC cell migration and invasion, and MMP2 mRNA expression by blocking the translocation and phosphorylation of PLCγ. The results of the present study revealed that TSPAN1 has an important function in human PC cell migration and invasion by modulating MMP2 expression via PLCγ. Thus, the results indicate that the silencing of TSPAN1 may be a potential therapeutic target for the treatment of PC.

Tetraspanin 1 promotes epithelial-to-mesenchymal transition and metastasis of cholangiocarcinoma via PI3K/AKT signaling

BackgroundNumerous studies have demonstrated that tetraspanin 1 (TSPAN1), a transmembrane protein, functions as an oncoprotein in many cancer types. However, its role and underlying molecular mechanism in cholangiocarcinoma (CCA) progression remain unclear.MethodsIn the present study, the expression of TSPAN1 in human CCA and adjacent nontumor tissues was examined using real-time PCR, western blot and immunohistochemistry. The effect of TSPAN1 on proliferation and metastasis was evaluated by functional assays both in vitro and in vivo. A luciferase reporter assay was performed to investigate the interaction between microRNA-194-5p (miR-194-5p) and TSPAN1 3′-untranslated region. Co-immunoprecipitation (co-IP) was used to confirm the interaction between TSPAN1 protein and integrin α6β1 and western blot was used to explore TSPAN1 mechanism.ResultsWe found that TSPAN1 was frequently upregulated in CCA and high levels of TSPAN1 correlated with TNM stage, especially metastasis in CCA. TSPAN1 overexpression promoted CCA growth, metastasis, and induced epithelial-to-mesenchymal transition (EMT), while its silencing had the opposite effect both in vitro and in vivo. To explore the differential expression of TSPAN1, we screened miR-194-5p as the upstream regulator of TSPAN1. A combination of high-level TSPAN1 and low-level miR-194-5p predicted poor prognosis in patients with CCA. Furthermore, in accordance with the functional characteristics of the TSPAN superfamily, we proved that TSPAN1 interacted with integrin α6β1 to amplify the phosphoinositide-3-kinase (PI3K)/AKT/glycogen synthase kinase (GSK)-3β/Snail family transcriptional repressor (Snail)/phosphatase and tensin homolog (PTEN) feedback loop.ConclusionThe results indicate that TSPAN1 could be a potential therapeutic target for CCA.

Discovery of a diagnostic biomarker for colon cancer through proteomic profiling of small extracellular vesicles

BackgroundSmall extracellular vesicles (small-EVs) are membranous vesicles that contain unique information regarding the condition of cells and contribute to the recruitment and reprogramming of components associated with the tumor environment. Therefore, many researchers have suggested that small-EV proteins are potential biomarkers for diseases such as cancer. Colon cancer (CC) is one of the most common causes of cancer-related deaths worldwide. Biomarkers such as carcinoembryonic antigen (CEA) show low sensitivity (~ 40%), and thus the demand for novel biomarkers for CC diagnosis is increasing.MethodsIn this study, we identified biomarkers for diagnosing CC through proteomic analysis of small-EVs from CC cell lines. These small-EVs were characterized by western blot analysis, nanoparticle tracking analysis, and transmission electron microscopy and analyzed using mass spectrometry.ResultsFive selected proteins were found to be upregulated in CC by western blot analysis. Among the candidate proteins, tetraspanin 1 (TSPAN1) was found to be upregulated in plasma EVs from CC patients compared to those from healthy controls (HCs) with 75.7% sensitivity.ConclusionsThese results suggest that TSPAN1 is a potent non-invasive biomarker for CC detection. Our experimental strategy provides useful insights into the identification of cancer-specific non-invasive biomarkers.

Tetraspanin 1 inhibits TNFα-induced apoptosis via NF-κB signaling pathway in alveolar epithelial cells.

Tetraspanin family plays an important role in the pathogenesis of cancer, but its role in lung fibrosis is unknown. To determine whether tetraspanin 1 (TSPAN1), a member of the family, may be involved in the pathogenesis of pulmonary fibrosis. TNFα -stimulated human alveolar epithelial (A549) and alveolar epithelial type II cell (AT2) were treated in vitro. Murine pulmonary fibrosis model was generated by injection of bleomycin (BLM). The expression of TSPAN1 was examined in vivo using the bleomycin-induced lung fibrosis model and tissue sample of IPF patients. Then we transfected the cells with TSPAN1 siRNA or plasmid and detected the expression changes of related proteins and cell apoptosis. In our study, we found that TSPAN1 was markedly down-regulated in lung tissue of patients with idiopathic pulmonary fibrosis (IPF) and in bleomycin-induced pulmonary fibrosis in mice. We also found that TSPAN1 was significantly down-regulated in A549 and primary (AT2) cells following exposure to TNFα. Meanwhile, TSPAN1 inhibited p-IκBα, which attenuated nuclear NF-κB translocation and activation and inhibited apoptosis. We demonstrated that TSPAN1 reduced Bax translocation and caspase-3 activation, inhibited the apoptosis by regulating the NF-κB pathway in response to TNFα. We conclude that TSPAN1 mediated apoptosis resistance of alveolar epithelial cells by regulating the NF-κB pathway. TSPAN1 may be a potential therapeutic target for pulmonary fibrosis or acute lung injury.

Expression and function of tetraspanin 1 in esophageal carcinoma.

The present study explored the expression of tetraspanin 1 (TSPAN1) in esophageal carcinoma (EC) and its association with clinicopathological factors. TSPAN1 small interfering RNA (siRNA) was designed to target the TSPAN1 gene in Eca-109 cells in order to explore the biological function of TSPAN1 in the proliferation and apoptosis of EC. The results demonstrated that the level of TSPAN1 expression in EC tissue was significantly increased compared with that in adjacent normal tissue (P<0.001). TSPAN1 expression was also associated with histological differentiation, depth of invasion, lymph node metastasis (all P<0.05) and Ki-67 (P<0.01). However, no association was observed between TSPAN expression and gender, age or location (P>0.05). In addition, silencing TSPAN1 markedly inhibited proliferation while increasing the apoptosis rate of Eca-109 cells, which was demonstrated by detecting the expression of the cell proliferation-associated gene Ki-67 and the apoptotic gene caspase-3 (P<0.05). Taken together, these results indicated that TSPAN1 functions as a tumor-associated gene in EC through promoting cell proliferation and suppressing apoptosis, and siRNA technology may provide an advanced alternative in the development of therapeutics for EC.

MiR-491-3p suppresses the growth and invasion of osteosarcoma cells by targeting TSPAN1

Osteosarcoma (OS) is the most common primary bone cancer, and frequently leads to mortality as a result of rapid proliferation and metastasis. Recent data highlight the important role of microRNAs (miRs) in human cancers, including OS, providing a novel method for its diagnosis and treatment. In the present study, it was identified that miR‑491‑3p expression was frequently decreased in OS tissues and OS cell lines. Restored miR‑491‑3p expression suppressed the growth and invasion of OS cells. Bioinformatics and experimental analysis indicated that tetraspanin 1 (TSPAN1) is a direct target of miR‑491‑3p in OS. The TSPAN1 mRNA level was inversely associated with the miR‑491‑3p level in OS tissues and cell lines. Consistent with this, TSPAN1 knockdown inhibited the growth and invasion of OS cells. In conclusion, these data provide compelling evidence that miR‑491‑3p functions as a tumor suppressor in OS to attenuate the potential of growth and invasion by targeting TSPAN1.