Association of NET-1 gene expression with human hepatocellular carcinoma

Role of Tetraspanins in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is characterized by high prevalence, morbidity, and mortality. Liver cancer is the sixth most common cancer worldwide; and its subtype, HCC, accounts for nearly 80% of cases. HCC progresses rapidly, and to date, there is no efficacious treatment for advanced HCC. Tetraspanins belong to a protein family characterized by four transmembrane domains. Thirty-three known tetraspanins are widely expressed on the surface of most nucleated cells and play important roles in different biological processes. In our review, we summarize the functions of tetraspanins and their underlying mechanism in the life cycle of HCC, from its initiation, progression, and finally to treatment. CD9, TSPAN15, and TSPAN31 can promote HCC cell proliferation or suppress apoptosis. CD63, CD151, and TSPAN8 can also facilitate HCC metastasis, while CD82 serves as a suppressor of metastasis. TSPAN1, TSPAN8, and CD151 act as prognosis indicators and are inversely correlated to the overall survival rate of HCC patients. In addition, we discuss the potential of role of the tetraspanin family proteins as novel therapeutic targets and as an approach to overcome drug resistance, and also provide suggestions for further research.

Quantitative Proteomics Analysis of FFPE Tumor Samples Reveals the Influences of NET-1 siRNA Nanoparticles and Sonodynamic Therapy on Tetraspanin Protein Involved in HCC

Hepatocellular carcinoma (HCC) poses a severe threat to human health. The NET-1 protein has been proved to be strongly associated with HCC proliferation and metastasis in our previous study. Here, we established and validated the NET-1 siRNA nanoparticles system to conduct targeted gene therapy of HCC xenograft in vivo with the aid of sonodynamic therapy. Then, we conducted a label-free proteome mass spectrometry workflow to analyze formalin-fixed and paraffin-embedded HCC xenograft samples collected in this study. The result showed that 78 proteins were differentially expressed after NET-1 protein inhibited. Among them, the expression of 17 proteins upregulated and the expression of 61 proteins were significantly downregulated. Of the protein abundance, the vast majority of Gene Ontology enrichment terms belong to the biological process. The KEGG pathway enrichment analysis showed that the 78 differentially expressed proteins significantly enriched in 45 pathways. We concluded that the function of the NET-1 gene is not only to regulate HCC but also to participate in a variety of biochemical metabolic pathways in the human body. Furthermore, the protein–protein interaction analysis indicated that the interactions of differentially expressed proteins are incredibly sophisticated. All the protein–protein interactions happened after the NET-1 gene has been silenced. Finally, our study also provides a useful proposal for targeted therapy based on tetraspanin proteins to treat HCC, and further mechanism investigations are needed to reveal a more detailed mechanism of action for NET-1 protein regulation of HCC.

Evaluation of therapeutic effect of targeting nanobubbles conjugated with NET-1 siRNA by shear wave elastography: an in vivo study of hepatocellular carcinoma bearing mice model

This study aimed at investigating the tumor stiffness of hepatocellular carcinoma (HCC) bearing mice model in vivo to evaluate the therapeutic efficacy of targeting nanobubbles (TNBS) conjugated with NET-1 siRNA (NET-1 siRNA-TNBS). Also tested whether shear wave elastography (SWE) could demonstrate the pathological tumor changes and used to monitor therapeutic efficacy as a noninvasive method. The HCC bearing mice model was established by injecting human HCC cell line (HepG2). The mice were then divided into three groups randomly, and were treated with TNBS conjugated with NET-1 siRNA, TNBS conjugated with negative control gene, and saline as control. US-SWE was performed for three times. SWE values of all the tumors in three groups were increased with tumor growth. Emax was correlated with tumor size (p < .05). NET-1 gene (treatment group) significantly delayed the growth of tumor size compared to other two groups (p < .0001), showing a significantly increased Emax (p < .05). Immunohistochemical results showed that the NET-1 protein expression was significantly lower than the negative control and blank groups. In conclusion, TNBS conjugated with NET-1 siRNA inhibited tumor growth and prolonged the life of experimental animals. SWE provided a noninvasive and real time imaging method to detect the changes in tumor development.

Preparation of novel targeting nanobubbles conjugated with small interfering RNA for concurrent molecular imaging and gene therapy in vivo

The aim of this study was to establish a novel targeting nanobubble (TNB) conjugated with small interfering RNA (siRNA)-cyanine 5 (Cy5) and to validate its theranostic ability in vivo. The TNB conjugated with neuroepithelial transforming gene 1 (NET-1) siRNA-Cy5 was prepared by thin-film hydration and mechanical sonication method. A hepatocellular carcinoma (HCC) xenograft model was established by subcutaneously injecting SMMC-7721 cells in BALB/c nude mice. The NET-1 siRNA-conjugated TNB was utilized for accurate contrast-enhanced ultrasound in vivo imaging, which was enabled by the target ligand GPC-3 antibody and specific gene transfection with the aid of low-frequency ultrasound (LFUS) irradiation. BALB/c nude mice bearing tumors were randomized into 5 groups and irradiated with LFUS for 5 min after TNB administration; mice were treated twice a week for a total of 60 d. The mean particle size of TNB was <500 nm. Mice treated with NET-1 siRNA-conjugated TNB showed a significant decrease in tumor growth and the highest survival rate. Our findings offer an effective and safe gene vehicle and probe for molecular imaging in vivo. It may improve the early diagnosis and treatment effects of HCC.-Wu, B., Shang, H., Liang, X., Sun, Y., Jing, H., Han, X., Cheng, W. Preparation of novel targeting nanobubbles conjugated with small interfering RNA for concurrent molecular imaging and gene therapy in vivo.

Inhibition of NET-1 suppresses proliferation and promotes apoptosis of hepatocellular carcinoma cells by activating the PI3K/AKT signaling pathway

The present study aimed to elucidate the underlying mechanism of neuroepithelial cell transforming 1 (NET-1), a member of the Ras homolog gene family, in hepatocellular carcinoma (HCC). To determine the association between the expression of NET-1 and the proliferation and migration of MHCC97-H cells, the cells were transfected with NET-1 small interfering (si)RNA and si negative control. Following transfection with NET-1 siRNA, the proliferation rate of MHCC97-H cells decreased significantly and the percentage of apoptotic cells increased. The HCC cell line MHCC97-H was used in the present study as it exhibited an increased expression level of NET-1 compared with the MHCC97-L cell line. Expression levels of apoptosis-associated proteins including apoptosis regulator Bax (Bax), cyclinD1, apoptosis regulator Bcl-2 (Bcl-2) and caspase-3 were determined. Expression levels of phosphoinositide 3-kinase (PI3K) and protein kinase B (AKT) and their phosphorylated forms were also measured by western blotting. Following NET-1 knockdown, the expression of Bax and cyclinD1 decreased, the expression of Bcl-2 and caspase-3 increased, and the PI3K/AKT signaling pathway was inhibited. The results of the present study suggest that inhibition of NET-1 can suppress the progression of HCC by targeting the PI3K/AKT signaling pathway. NET-1 expression level in HCC cells increased compared with normal liver cells.

VTIQ evaluates antitumor effects of NET-1 siRNA by UTMD in HCC xenograft models

The present study used a virtual touch tissue imaging and quantification (VTIQ) method to investigate the change in elasticity in xenograft tumor tissue models following silencing of the neuroepithelial-transforming protein 1 (NET-1) gene by ultrasound-targeted microbubble destruction (UTMD). A total of 24 xenograft models were established by subcutaneous injection of human hepatocellular carcinoma SMMC-7721 cells in BALB/c female nude mice. Then, NET-1 small interfering RNA (siRNA)-conjugated nanobubbles and a glypican-3 antibody were synthesized. The mean and maximum shear wave speed (SWS_mean and SWS_max) in the tumor tissue were measured prior to, during, and following therapy using VTIQ. The growth of the tumor size and survival time were recorded. The levels of NET-1 protein were evaluated by immunohistochemical staining. In addition, tumor, liver and kidney tissues of the nude mice were collected to confirm whether gene transfection treatment was toxic in vivo. In the UTMD delivery gene group, SWS_mean was correlated with the maximum diameter of the tumor (r=0.9806, P=0.0194). The immunohistochemical staining data indicated that the level of NET-1 protein in the treated groups was significantly decreased compared with those in the control groups. Additionally, no structural damage was observed in the nude mice liver and kidney tissues following treatment. Therefore, VTIQ measurement identified potential changes in the elastic properties of the tumors, which in turn may be associated with the stages of tumor development. The delivery method, UTMD, improves the antitumor effects of NET-1 siRNA and supports gene transfection as a promising therapeutic strategy.

Knockdown of TSPAN1 by RNA Silencing and Antisense Technique Inhibits Proliferation and Infiltration of Human Skin Squamous Carcinoma Cells

Aim

To explore the function of TSPAN1 in squamous cell skin carcinoma by means of TSPAN1-specific siRNA and antisense oligonucleotide techniques.

Methods

pU6H1-GFP-siRNA TSPAN1 and pcDNA3.1 antisense TSPAN1 were constructed and transfected into squamous cell skin carcinoma cell line A431 cells to knock down TSPAN1 gene expression. The levels of TSPAN1 mRNA and protein expression were detected by semiquantitive RT-PCR and Western blot, respectively. The proliferation rates of A431 cells were determined by MTT assay and flow cytometry. Lastly, the migration and infiltration of A431 cells were determined by the Transwell migration assay.

Results

Transfection with either pU6H1-GFP-siRNA TSPAN1 or pcDNA3.1 antisense TSPAN1 led to an obvious reduction of expression levels of TSPAN1 mRNA and protein in A431 cells, respectively. The proliferation, migration and infiltration of A431 cancer cells were significantly inhibited at 48 hours after transfection of plasmids harboring TSPAN1 siRNA and antisense RNA.

Conclusion

The TSPAN1 gene might play a role in the proliferation of squamous cell carcinoma of the skin and be associated with cancer cell motility, implying a function of the gene in the development of skin cancer.

Clinicopathological Significance of Overexpression of TSPAN1, KI67 and CD34 in Gastric Carcinoma

To investigate the expression of TSPAN1 (Gene ID: 10103), Ki67 and CD34 in gastric carcinomas and the clinicopathological significance, the expression of TSPAN1, Ki67 and CD34 was detected in 86 cases of gastric carcinoma, paraffin-embedded sections using an immunohistochemical method. The rates of overexpression of TSPAN1, Ki67 and CD34 in gastric carcinomas were 56.98%, 74.42%, and 62.79%, respectively. The overexpression of these markers was positively correlated with clinical stage and negatively correlated with survival rates (at 3 and 5 years). The overexpression of TSPAN1 and Ki67 was negatively correlated with carcinoma differentiation, and the overexpression of TSPAN1 and CD34 was positively correlated with infiltration and lymph node status of the tumor. Thus, overexpression of TSPAN1, Ki67 and CD34 in gastric cancer tissues is associated with development of the cancer. The detection of expression of TSPAN1, Ki67 and CD34 in gastric cancer may provide useful prognostic information for patients with the disease.

Suppression of TSPAN1 by RNA Interference Inhibits Proliferation and Invasion of Colon Cancer Cells in Vitro

Aims and background

To investigate effect of TSPAN1 downregulation by RNA interference (RNAi) on proliferation and invasion of human colon cancer cells in vitro.

Methods and study design

RNAi was performed using the vector (pU6H1-GFP)-based small-interfering RNA (siRNA) plasmid gene silencing system to specifically knock down TSPAN1 expression in a colon cancer cell line, HCT-8. The expression of TSPAN1 mRNA was detected by reverse-transcription polymerase chain reaction. TSPAN1 protein expression was observed using Western blots and immunofluorescent microscopy. Cell proliferation and cell cycle assay were measured using methyl thiazolyl tetrazolium (MTT) and flow cytometry, respectively. The invasive ability of HCT-8 cells was examined using a duel culture chamber separated by polycarbonate membranes coated with Matrigel (8.0-μm pore size).

Results

After transfection with the TSPAN1 siRNA plasmid, TSPAN1 mRNA and protein expression was significantly decreased. The decrease in mRNA and protein was associated with a significant decrease in TSPAN1 fluorescent staining and a decrease in cell proliferation due to cell cycle arrest in the G1/G0 phase. A significant decrease in the number of invading HCT-8 cells was associated with these changes.

Conclusion

RNAi-mediated downregulation of TSPAN1 expression significantly inhibits the proliferation and invasion of colon cancer cells in vitro. This finding suggests that TSPAN1 plays an important role in colon cancer progression, and RNAi targeting of TSPAN1 may be a potential therapeutic strategy for the treatment of colon cancer. Free full text available at www.tumorionline.it

Effect of NET-1 siRNA conjugated sub-micron bubble complex combined with low-frequency ultrasound exposure in gene transfection

The present study evaluated the effect of NET-1 siRNA-conjugated sub-micron bubble (SMB) complexes combined with low-frequency ultrasound exposure in gene transfection. The NET-1 gene was highly expressed level in SMMC-7721 human hepatocellular carcinoma cell line. The cells were divided into seven groups and treated with different conditions. The groups with or without low-frequency ultrasound exposure, groups of adherent cells, and suspension cells were separated. The NET-1 siRNA-conjugated SMB complexes were made in the laboratory and tested by Zetasizer Nano ZS90 analyzer. Flow cytometry was used to estimate the transfection efficiency and cellular apoptosis. Western blot and quantitative real-time polymerase chain reaction (qPCR) were used for the estimation of the protein and mRNA expressions, respectively. Transwell analysis determined the migration and invasion capacities of the tumor cells. The results did not show any difference in the transfection efficiency between adherent and suspension cells. However, the NET-1 siRNA-SMB complexes combined with low-frequency ultrasound exposure could enhance the gene transfection effectively. In summary, the NET-1 siRNA-SMB complexes appeared to be promising gene vehicle.

Effects of Triple Effective RNA (teRNA) on the Inhibition of Hepatocellular Carcinoma Cells

The occurrence and development of hepatocellular carcinoma (HCC) is a complicate process involved in genetic mutation and epigenetic regulation. Successful HCC therapy needs multi-targets be involved. The aim of this study was to provide a triple effective RNA (teRNA) which composed of the specific siRNAs targeting NET-1 and VEGF and dsRNA activating TLR3, and explored its anti-HCC roles and mechanism. Real-time quantitative PCR (RT-qPCR), Western blot, immunofluorescence staining, MTT, Annexin V-FITC flow cytometry, Transwell and in-vitro Angiogenesis assay were used to measure the cell biological functions and protein expression analysis. Furthermore in in-vivo mouse model, teRNA inhibited tumor growth were detected by immunohistochemistry and TUNEL assay. Results showed that the proliferation, migration and angiogenesis of HCC cells were inhibited by teRNA effectively, the cell apoptosis also was induced, and further tumor growth was suppressed in-vivo. The gene silencing mechanism of teRNA was in an Ago2-dependent manner with no interferon response. The study suggests that NET-1, VEGF and TLR3 might be better targets for HCC treatment and combined these targets in form of a multi-target small RNA, teRNA could be a stagey for the development of anti-HCC drugs.

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.

The cancer-associated cell migration protein TSPAN1 is under control of androgens and its upregulation increases prostate cancer cell migration

Cell migration drives cell invasion and metastatic progression in prostate cancer and is a major cause of mortality and morbidity. However the mechanisms driving cell migration in prostate cancer patients are not fully understood. We previously identified the cancer-associated cell migration protein Tetraspanin 1 (TSPAN1) as a clinically relevant androgen regulated target in prostate cancer. Here we find that TSPAN1 is acutely induced by androgens, and is significantly upregulated in prostate cancer relative to both normal prostate tissue and benign prostate hyperplasia (BPH). We also show for the first time, that TSPAN1 expression in prostate cancer cells controls the expression of key proteins involved in cell migration. Stable upregulation of TSPAN1 in both DU145 and PC3 cells significantly increased cell migration and induced the expression of the mesenchymal markers SLUG and ARF6. Our data suggest TSPAN1 is an androgen-driven contributor to cell survival and motility in prostate cancer.

Advances in ultrasound-targeted microbubble-mediated gene therapy for liver fibrosis

Hepatic fibrosis develops as a wound-healing scar in response to acute and chronic liver inflammation and can lead to cirrhosis in patients with chronic hepatitis B and C. The condition arises due to increased synthesis and reduced degradation of extracellular matrix (ECM) and is a common pathological sequela of chronic liver disease. Excessive deposition of ECM in the liver causes liver dysfunction, ascites, and eventually upper gastrointestinal bleeding as well as a series of complications. However, fibrosis can be reversed before developing into cirrhosis and has thus been the subject of extensive researches particularly at the gene level. Currently, therapeutic genes are imported into the damaged liver to delay or prevent the development of liver fibrosis by regulating the expression of exogenous genes. One technique of gene delivery uses ultrasound targeting of microbubbles combined with therapeutic genes where the time and intensity of the ultrasound can control the release process. Ultrasound irradiation of microbubbles in the vicinity of cells changes the permeability of the cell membrane by its cavitation effect and enhances gene transfection. In this paper, recent progress in the field is reviewed with emphasis on the following aspects: the types of ultrasound microbubbles, the construction of an ultrasound-mediated gene delivery system, the mechanism of ultrasound microbubble–mediated gene transfer and the application of ultrasound microbubbles in the treatment of liver fibrosis.

Prognostic significance of Tspan9 in gastric cancer

Tetraspanins are a large superfamily of glycoproteins, which are engaged in a wide range of specific molecular interactions by forming tetraspanin-enriched microdomains. Tetraspanin 9 (Tspan9) is a previously poorly studied tetraspanin gene, which was predominantly identified as an amplified gene in serous Fallopian tube carcinoma. However, the expression and role of Tspan9 in gastric cancer have yet to be fully elucidated. The aim of the present study was to evaluate the expression and clinical significance of Tspan9 in gastric cancer. In the present study, 105 gastric cancer tissue samples and corresponding adjacent normal samples were detected for Tspan9 expression using immunohistochemistry; furthermore, the association between clinical characteristics and Tspan9 expression was also analyzed. Tspan9 expression was determined to be significantly lower in cancer samples compared with those in corresponding adjacent normal samples (P<0.001). However, its increased levels of expression in cancer samples appeared to demonstrate a poorer prognostic tendency, which is associated with deeper tumor depth (P=0.025), more nodal involvement (P=0.01), more advanced tumor/lymph node/metastasis (TNM) stages (P=0.017) and a larger tumor size (P=0.026). Additionally, multivariate analysis demonstrated that high expression of Tspan9 was an independent prognostic factor for poor overall survival (P<0.01). These results suggested that Tspan9 may be used as a potential prognostic factor in gastric cancer.

Multi-target siRNA: Therapeutic Strategy for Hepatocellular Carcinoma

Multiple targets RNAi strategy is a preferred way to treat multigenic diseases, especially cancers. In the study, multi-target siRNAs were designed to inhibit NET-1, EMS1 and VEGF genes in hepatocellular carcinoma (HCC) cells. And multi-target siRNAs showed better silencing effects on NET-1, EMS1 and VEGF, compared with single target siRNA. Moreover, multi-target siRNA showed greater suppression effects on proliferation, migration, invasion, angiogenesis and induced apoptosis in HCC cells. The results suggested that multi-target siRNA might be a preferred strategy for cancer therapy and NET-1, EMS1 and VEGF could be effective targets for HCC treatments.

Targeted nanobubbles in low-frequency ultrasound-mediated gene transfection and growth inhibition of hepatocellular carcinoma cells

The use of SonoVue combined with ultrasound exposure increases the transfection efficiency of short interfering RNA (siRNA). The objective of this study was to prepare targeted nanobubbles (TNB) conjugated with NET-1 siRNA and an antibody GPC3 to direct nanobubbles to hepatocellular carcinoma cells. SMMC-7721 human hepatocellular carcinoma cells were treated with six different groups. The transfection efficiency and cellular apoptosis were measured by flow cytometry. The protein and messenger RNA (mRNA) expression were measured by Western blot and quantitative real-time PCR, respectively. The migration and invasion potential of the cells were determined by Transwell analysis. The results show that US-guided siRNA-TNB transfection effectively enhanced gene silencing. In summary, siRNA-TNB may be an effective delivery vector to mediate highly effective RNA interference in tumor treatment.

TM4SF1 Promotes Proliferation, Invasion, and Metastasis in Human Liver Cancer Cells

Transmembrane 4 superfamily member 1 (TM4SF1) is a member of tetraspanin family, which mediates signal transduction events regulating cell development, activation, growth and motility. Our previous studies showed that TM4SF1 is highly expressed in liver cancer. HepG2 cells were transfected with TM4SFl siRNA and TM4SF1-expressing plasmids and their biological functions were analyzed in vitro and in vivo. HepG2 cells overexpressing TM4SF1 showed reduced apoptosis and increased cell migration in vitro and enhanced tumor growth and metastasis in vivo, whereas siRNA-mediated silencing of TM4SF1 had the opposite effect. TM4SF1 exerts its effect by regulating a few apoptosis- and migration-related genes including caspase-3, caspase-9, MMP-2, MMP-9 and VEGF. These results indicate that TM4SF1 is associated with liver tumor growth and progression, suggesting that TM4SF1 may be a potential target for treatment of liver cancer in future.

Tetraspanin 1 is involved in survival, proliferation and carcinogenesis of pancreatic cancer

Pancreatic cancer (PCC) is one of the most difficult cancers to treat and the 10th leading cause of cancer-related death in worldwide. Studies have demonstrated that the tetraspanin 1 (Tspan1) is overexpressed in various cancers and may be a potential therapeutic strategy for the treatment of different cancers. However, the possible role of Tspan1 in PCC is still unknown. In the present study, our data revealed that the increased Tspan1 in PCC tissues was associated with the clinicopathological features and survival rate of PCC patient. We also investigated the effects of Tspan1 gene knockdown on the biological behavior of human PCC. The expression of Tspan1 (detected by immunohistochemistry, qRT-PCR and western blot analysis) derived from human PCC tissues and cell lines (AsPC-1 and PANC-1), were significantly elevated compared with those of the control (P<0.05). Transfection with siRNA-targeting Tspan1 significantly decreased proliferation, increased the apoptosis and reduced migration and invasion of AsPC-1 and PANC-1 cells. The present study demonstrated that Tspan1 plays an important role in PCC carcinogenic progression, including migration and invasion. The siRNA targeting of Tspan1 may be a potential therapeutic strategy for the treatment of PCC.

Inhibition of skin squamous cell carcinoma proliferation and promote apoptosis by dual silencing of NET-1 and survivin

The simultaneous silencing of multiple upregulated genes is an attractive and viable strategy to treat many incurable diseases including cancer. In the present study, skin squamous cell carcinoma (SSCC) tissue microarray was constructed and the expression of NET-1 and survivin was identified. The high expression of NET-1 and survivin gene in SSCC was confirmed as an important event for the formation and development of the cancer. A total of 100 primary SSCC patients were included in the present study. Expression of NET-1 and survivin in cancer cells was evaluated immunohistochemically in tissue microarrays. The interaction between NET-1 and survivin in SSCC by co-immunoprecipitation was subsequently verified by producing the siRNA sequence targeting the single gene (siRNA-NET-1 and siRNA-survivin) as well as NET-1 and survivin gene (one-chain-double-target siRNA). The levels of NET-1 and survivin mRNA and protein expression in A431 cells were detected by RT-qPCR and western blotting, and the expression of related genes including vascular endothelial growth factor (VEGF), cortactin, Bcl-2, caspase-3 and -8 was identified using RT-qPCR. The protein localization and expression of NET-1 and survivin in A431 cells were documented by immunohistochemistry and immuno-fluorescence staining. The proliferation and apoptosis of A431 cells were detected by CCK-8 assay and flow cytometry (FCM). The tissue microarray showed that NET-1 and survivin were highly expressed in SSCC, while the correlation analysis showed NET-1 expression was positively associated with survivin. In addition, we reported that using the one-chain-double-target siRNA conjugate composed of NET-1 and survivin siRNA sequences in the same backbone inhibited proliferation and promoted apoptosis of SSCC. The one-chain-double-target siRNA showed further downregulation on NET-1 and survivin mRNA and protein levels compared with NET-1 siRNA or survivin siRNA. It also exhibited greater suppression on proliferation and triggering of apoptosis in A431 cells than NET-1 siRNA or survivin siRNA. This result may be explained by the significant downregulation of VEGF, cortactin and Bcl-2, and upregulation of caspase-3 and -8. NET-1 and survivin were overexpressed in SSCC and an interaction between NET-1 and survivin was identified. The one-chain-double-target siRNA appears to be superior in inhibiting cell proliferation and promoting apoptosis compared with the single target siRNA. NET-1 and survivin may have correlative signaling pathways with VEGF, cortactin, Bcl-2, caspase-3 and -8. Simultaneous silencing of NET-1 and survivin using one-chain-double-target siRNA thus provides an advantageous alternative in the development of therapeutics for SSCC.

MiR-200a enhances the migrations of A549 and SK-MES-1 cells by regulating the expression of TSPAN1

MicroRNA-200a (miR-200a) has been reported to regulate tumour progression in several tumours; however, little is known about its role in non-small cell lung cancer cells (NSCLCs). Here, we found that miR-200a was up-regulated in A549 and SK-MES-1 cells compared with normal lung cells HELF. By a series of gain-of-function and loss-offunction studies, over-expression of miR-200a was indicated to enhance cells migration, and its knock-down inhibited migration of cells in NSCLC cell lines. Furthermore, miR-200a was identified to induce TSPAN1 expression which was related to migration. TSPAN1 was proved to induce migration, and so up-regulation of TSPAN1 by miR-200a may explain why over-expressing miR-200a promotes NSCLC cells migration.

Prognostic significance of neuroepithelial transforming gene 1 in adenocarcinoma of the oesophagogastric junction

Background

Neuroepithelial transforming gene 1 (NET1) mediates tumour invasion and metastasis in a number of cancers, including gastric adenocarcinoma. It is an indicator of poor prognosis in breast cancer and glioma. This study examined NET1 expression and its prognostic significance in patients with adenocarcinoma of the oesophagogastric junction (AOG).

Methods

NET1 expression was measured by immunohistochemistry in a tissue microarray, constructed from biobanked tissue collected over a 10-year interval, and linked to a prospectively maintained clinical database.

Results

Using the Siewert classification for AOG, type I tumours expressed significantly higher levels of NET1, with lowest expression in type III and intermediate levels in type II (P = 0·001). In patients with AOG type III, NET1-positive patients were more likely to be female (P = 0·043), have advanced stage cancer (P = 0.035), had a higher number of transmural cancers (P = 0·006) and had a significantly higher median number of positive lymph nodes (P = 0·029). In this subgroup, NET1-positive patients had worse median overall (15 versus 23 months; P = 0·025) and disease-free (11 versus 36 per cent; P = 0·025) survival compared with NET1-negative patients.

Conclusion

Although existing data show differences in clinical and prognostic indices across AOG subtypes, there are no studies showing differences in tumour biology. These data suggest NET1, a known mediator of an aggressive tumour phenotype in a number of gastrointestinal cancers, is expressed differentially across AOG subtypes and may be of prognostic significance in the clinical management of this condition.

Expression and function of NET-1 in human skin squamous cell carcinoma

To evaluate the clinicopathological significance of NET-1 in human skin squamous cell carcinoma (SSCC). The expression of NET-1 and Ki67 protein was detected using immunostaining from 60 SSCC cases, 50 SIN samples and ten normal skin tissues. The vectors expressing NET-1, siRNA NET-1 and shRNA NET-1 were constructed, as well as negative controls (target-off). In transfected A431 cells, the expression of NET-1 was detected by qRT-PCR, Western blot and immunofluorescence staining; the proliferation and migration of cells was evaluated by MTT, flow cytometry, wound healing and transwell chamber assays. The stable cell lines transfected with shRNANET-1 was inoculated in nude mice for in vivo study. (1) The levels of NET-1 were significantly higher in SSCC (96.67 %) and SIN III (93.75 %) than that in SIN I and II (41.18 %), (P < 0.05). NET-1 expression was significantly enhanced in spindle-cell SSCC (75 %) versus other histological types (P < 0.05). (2) The expression of NET-1 in A431 cells transfected with siRNANET-1 or shRNANET-1 was significantly decreased; the proliferation and migration of these cells were obviously inhibited as compared to controls (P < 0.05). (3) The growth of subcutaneous tumors was significantly inhibited associated with reduction in the expression of NET-1 vs. the negative control or untreated group (P < 0.05). The overexpression of NET-1 in tumor cells may be closely related to the malignant phenotype of SSCC. NET-1 RNAi used in this study can specifically and effectively downregulate NET-1 gene expression; thus SSCC proliferation, invasion and tumor growth were attenuated. NET-1 might be one of the potential targets for SSCC therapy.

Study of RNA Interference Targeting NET-1 Combination with Sorafenib for Hepatocellular Carcinoma Therapy In Vitro and In Vivo

The aim of this study is to explore the inhibitory effects of RNA interference (RNAi) targeting NET-1 or combined with sorafenib on HCC in vitro and in vivo and the possible underlying mechanisms. The expressions of NET-1 mRNA and protein were detected by RT-QPCR and western blot. The ability of proliferation was determined by CCK-8 assay. Apoptosis was examined by flow cytometry (FCM). Abilities of migration and invasion were measured by scratch-wound assay and transwell assay. MHCC97H cells with stable transfection of NET-1shRNA were injected subcutaneously to prepare nude mice model of HCC and Caspase-3, Caspase-8, and Caspase-9 mRNAs of tumor tissues in different groups were examined. NET-1 mRNA and protein were reduced sharply in MHCC97H cells transfected with NET-1shRNA. The abilities of proliferation and migration were inhibited and apoptosis was promoted in either NET-1shRNA or sorafenib as compared with untreated cells in vitro and in vivo (P < 0.05). The mRNA levels of caspase-3, caspase-8, and caspase-9 of tumor tissues were reduced in different treatment groups compared with untreated group, particularly in combination group. (P < 0.05). The combination NET-1shRNA with sorafenib dramatically enhanced the effects of sorafenib antitumor ,which may involve in blocking ras signaling pathway and stimulating apoptotic pathways simultaneously.

Expression of neuroepithelial transforming gene 1 is enhanced in oesophageal cancer and mediates an invasive tumour cell phenotype

INTRODUCTION

Neuroepithelial Transforming Gene 1 (NET1) is a well characterised oncoprotein and a proven marker of an aggressive phenotype in a number of cancers, including gastric adenocarcinoma. We aimed to investigate whether NET1 plays a functional role in oesophageal cancer (OAC) and its pre-malignant phenotype Barrett's oesophagus.

METHODS

Baseline NET1 mRNA levels were determined by qPCR across a panel of six cell lines, including normal oesophageal, Barrett's and OAC derived cells. Quantification of NET1 protein in OAC cells was performed using Western blot and immunofluorescence. NET1 expression was modulated by treating with lysophosphatidic acid (LPA) and NET1-specific siRNA. The functional effects of NET1 knockdown were assessed in vitro using proliferation, migration and invasion assays.

RESULTS

NET1 expression was increased in Barrett's and in OAC-derived cells in comparison to normal oesophageal cells. The highest expression was observed in OE33 a Barrett's-related OAC cell line. NET1 protein and mRNA expression was enhanced by LPA treatment in OAC and furthermore LPA treatment caused increased proliferation, migration and invasion in a NET1-dependent manner. NET1 knockdown resulted in reduced OAC cell proliferation and invasion.

CONCLUSIONS

As found in other malignancies, NET1 expression is elevated in OAC and its pre-malignant phenotype, Barrett's oesophagus. NET1 promotes OAC cell invasion and proliferation and it mediates LPA-induced OAC cell migration.

Inhibition of hepatocellular carcinoma growth and angiogenesis by dual silencing of NET-1 and VEGF

Simultaneous silencing of multiple up-regulated genes is an attractive and viable strategy to treat many incurable diseases including cancer. Herein we used dual gene targeted siRNA (DGT siRNA) conjugate composed of NET-1 and VEGF siRNA sequences in the same backbone could inhibit growth and angiogenesis HCC. DGT siRNA showed a further down regulation on VEGF mRNA and protein levels compared with NET-1 siRNA or VEGF siRNA, but not on NET-1 expression. It also exhibited greater suppression on proliferation and trigger of apoptosis in HepG2 cells than NET-1 siRNA or VEGF siRNA; this could be explained by the significant down regulation of cyclin D1 and Bcl-2. A lower level of ANG2 mRNA and protein was detected in HUVEC cultured with supernatant of HepG2 cells treated with DGT siRNA than that of VEGF siRNA or NET-1 siRNA, resulting in much more inhibited angiogenesis of HUVEC. Tumor growth was inhibited and microvessel density dropped in the xenograft tumor models compared to the untreated controls. NET-1 and VEGF silencing play a key role in inhibiting hepatocellular cell proliferation, promoting apoptosis, and reducing angiogenesis. Simultaneous silencing of NET-1 and VEGF using DGT siRNA construct may provide an advantageous alternative in development of therapeutics for Hepatocellular carcinoma.

Neuroepithelial transforming protein 1 short interfering RNA-mediated gene silencing with microbubble and ultrasound exposure inhibits the proliferation of hepatic carcinoma cells in vitro

OBJECTIVES

Short interfering RNA (siRNA) has been used to knock down the expression of targeted genes in a process known as RNA interference. However, the key to RNA interference is the efficient intracellular delivery of the siRNA. In this study, we sought to enhance the efficiency of transduction and find a novel therapy for hepatic carcinoma.

METHODS

Three types of neuroepithelial transforming protein 1 (NET-1) siRNAs (labeled fluorescent) were designed and transduced into HepG2 cells. Then the most effective one in silencing NET-1 was determined. The HepG2 cells were divided into 5 groups: untreated control; delivery of siRNA; delivery of siRNA using Lipofectamine 2000 (Invitrogen, Carlsbad, CA; group L); delivery of siRNA using ultrasound exposure and microbubbles (group US); and delivery of siRNA using Lipofectamine, ultrasound exposure, and microbubbles (group LUS). The efficiency of siRNA transfer was determined by detection of luciferase activity on microscopy; NET-1 expression was assayed by reverse transcription-polymerase chain reaction and western blotting; and proliferation investigations of the HepG2 cells were performed. RESULTS- The transfection efficiency of microbubbles combined with ultrasound exposure was nearly equal to Lipofectamine-mediated transfection (P = .609). More importantly, the combination of Lipofectamine, microbubbles, and ultrasound exposure effectively reduced NET-1 expression compared with the other groups (P < .01). Furthermore, the proliferation of cells in groups L, US, and LUS was visibly inhibited between 24 and 72 hours.

CONCLUSIONS

The use of a microbubble contrast agent combined with ultrasound exposure could be a potent physical method for increasing gene delivery efficiency. This technique is a promising nonviral approach that can be used in liver cancer.

Neuroepithelial transforming gene 1 (Net1) binds to caspase activation and recruitment domain (CARD)- and membrane-associated guanylate kinase-like domain-containing (CARMA) proteins and regulates nuclear factor κB activation

The molecular complexes containing CARMA proteins have been recently identified as a key components in the signal transduction pathways that regulate activation of nuclear factor κB (NF-κB) transcription factor. Here, we used immunoprecipitation coupled with mass spectrometry to identify cellular binding partners of CARMA proteins. Our data indicate that the Rho guanine nucleotide exchange factor Net1 binds to CARMA1 and CARMA3 in resting and activated cells. Net1 expression induces NF-κB activation and cooperates with BCL10 and CARMA proteins in inducing NF-κB activity. Conversely, shRNA-mediated abrogation of Net1 results in impaired NF-κB activation following stimuli that require correct CARMA-BCL10-MALT1 complex formation and functioning. Microarray expression data are consistent with a positive role for Net1 on NF-κB activation. Thus, this study identifies Net1 as a CARMA-interacting molecule and brings important information on the molecular mechanisms that control NF-κB transcriptional activity.

Prognostic significance of neuroepithelial transforming protein 1 in hepatocellular carcinoma

OBJECTIVE

Recent works have demonstrated that neuroepithelial transforming protein 1 (NET-1) gene expression is associated with proliferation, metastasis, and clinical stages of human hepatocellular carcinoma (HCC). To investigate its prognostic significance in HCC, which currently is unknown, the authors examined the correlation between NET-1 expression and prognosis in patients with HCC.

METHODS

Immunohistochemical staining was used to determine NET-1 expression level in 368 paired HCC and normal liver tissue (NLT) specimens. Kaplan-Meier survival and Cox regression analyses were performed to evaluate the prognosis of HCC.

RESULTS

Among 368 specimens of HCC, the positive rate of NET-1 protein expression in HCC tissues was 86.7% (319/368), and the increased NET-1 expression was correlated significantly with high Edmondson-Steiner grade (p = .02) and TNM stage (p = .01). The expression level of NET-1 in HCC tissues was associated with intrahepatic metastasis (p = .008) and portal vein infiltration (p = .007). HCC patients with the moderate-strong NET-1 positive expression had either poorer disease-free survival or poorer overall survival than patients with negative-low positive NET-1 expression (p = .001 and .002, respectively). A multivariate Cox regression analysis revealed that NET-1 protein expression (relative risk 5.8; p = .01) was an independent prognostic factor for patients with HCC.

CONCLUSION

Taken together, our study suggests for the first time that NET-1 status may be a new predictor of survival for HCC patients and provides the rationale for developing a novel therapy of targeting NET-1 against this fatal malignancy.

Clinicopathological significance of expression of Tspan-1, Jab1 and p27 in human hepatocellular carcinoma

The aim of this study was to investigate the expression of Tspan-1, Jab1 and p27 in human hepatocellular carcinoma (HCC) and their clinicopathological significance. The expression of Tspan-1, Jab1 and p27 was detected in HCC tissues, the tissues around cancer (76 cases), and the normal tissues around the liver hemangiomas (10 cases). The overexpression of Tspan-1 and Jab1 was found in HCC tissues, positively correlated with clinical stage and negatively correlated with survival rate. The expression of p27 was found inversely linked to which of Tspan-1 and Jab1. In conclusion, the expression of Tspan-1, Jab1 and p27 is significantly associated with development of HCC. Overexpression of Tspan-1 and Jab1 suggests poor prognosis but overexpression of p27 may expect good prognosis for patients with HCC.

Identification of metastasis-associated breast cancer genes using a high-resolution whole genome profiling approach

PURPOSE

We employed a whole genome tumor profiling approach in an attempt to identify DNA copy number alterations (CNAs) and new candidate genes that are correlated with the metastatic potential of a primary breast carcinoma and with progression at the metastatic site.

METHODS

Fifty-four small (≤ 2 cm), high grade, ER-positive, formalin-fixed invasive ductal carcinomas were suitable for whole genome profiling analysis. Twenty-four of them did not form metastases within 5-10 years (unmatched primaries, UP). Thirty tumors had at least one synchronous axillary lymph node metastasis (matched primaries, MP; matched lymph node metastases, ML). Genomic DNA was hybridized to high density (19k) BAC arrays. Statistical analysis revealed differential distributions of CNAs between UP and MP and between MP and ML, respectively. We selected 27 candidate genes for validation experiments using quantitative (Q-)PCR of genomic DNA. For tetraspanin TSPAN1, we studied mRNA expression levels in a separate cohort of primary breast carcinomas and in breast cell lines.

RESULTS

Matched primary (MP) tumors had a threefold higher rate of DNA copy number losses compared to UP tumors. In the UP-MP comparison, 186 BACs were differentially amplified or deleted. Most of them were localized to chromosomes 7p, 16q and 18q. In the MP-ML comparison, 131 BACs showed differential CNAs. Most of them were localized to chromosomes 1q and 20. By Q-PCR, seven candidate genes could be confirmed to show differential distributions of CNAs. TSPAN1 was amplified in UP and deleted in MP tumors. The gene was markedly downregulated in ER-negative and high-grade breast cancers.

CONCLUSIONS

Metastasizing tumors had a higher rate of deletions, suggesting possible inactivation of metastasis suppressor genes. We provide preliminary evidence that TSPAN1 may be another important breast cancer suppressor gene belonging to the tetraspanin superfamily.

Over-expression of neuroepithelial-transforming protein 1 confers poor prognosis of patients with gliomas

OBJECTIVE

Neuroepithelial-transforming protein 1 is a member of the guanine nucleotide exchange factor family, a group of proteins which are known to activate and thereby regulate Rho family members. Deregulation of neuroepithelial-transforming protein 1 expression has been found in certain types of human tumors. To investigate its prognostic value in human gliomas, which is currently unknown, we examined the correlation between neuroepithelial-transforming protein 1 expression and prognosis in patients with gliomas.

METHODS

Immunohistochemical staining was performed to detect neuroepithelial-transforming protein 1 expression patterns in the biopsies from 96 patients with primary gliomas. Kaplan-Meier survival and Cox's regression analyses were performed to evaluate the prognosis of patients.

RESULTS

Immunohistochemical analysis with anti-neuroepithelial-transforming protein 1 antibody revealed that neuroepithelial-transforming protein 1 was significantly associated with the Karnofsky performance scale score and World Health Organization grades of patients with gliomas. Especially, the positive expression rates of neuroepithelial-transforming protein 1 were significantly higher in patients with higher grade (P = 0.001) and lower Karnofsky's performance scale score (P = 0.005). The median survival of patients with high neuroepithelial-transforming protein 1 expression was significantly shorter than that with low expression and without expression (316, 892 and 1180 days, respectively). Cox's multifactor analysis showed that the Karnofsky performance scale (P = 0.01), World Health Organization grade (P = 0.008) and neuroepithelial-transforming protein 1 (P = 0.006) were independent prognosis factors for human glioma.

CONCLUSIONS

Taken together, our study indicates for the first time that neuroepithelial-transforming protein 1 status may be a highly sensitive marker for glioma prognosis and suggest that the expression patterns of neuroepithelial-transforming protein 1 might be a potent tool for predicting the clinical prognosis of glioma patients.

TSPAN1 protein expression: A significant prognostic indicator for patients with colorectal adenocarcinoma

AIM: To determine if TSPAN1 overexpression is associated with clinicopathological and prognostic factors in human colorectal adenocarcinoma.

METHODS: Total RNA was extracted in 20 human adenocarcinoma tissues for TSPAN1 mRNA assay by RT-PCR. Eighty-eight specimens of human colorectal adenocarcinoma were surgically removed. TSPAN1 protein levels in cancer tissues were determined by immunohistochemistry using a polyclonal antibody against self-prepared TSPAN1. The correlation between TSPAN1 expression and the clinicopathological factors and the overall survival rate was analyzed by univariate and multivariate assay.

RESULTS: TSPAN1 mRNA was detected in 90.0% (18/20) of cancerous tissues. The light density of TSPAN1 mRNA expression levels was 0.89 ± 0.30 in adenocarcinoma by gel-image system. TSPAN1 protein expression was detected in 78.41% (69/88) and weakly expressed in 40% normal colorectal tissues. There were significant differences between colorectal adenocarcinoma and normal control epithelium (P < 0.05). TSPAN1 protein expression in colorectal cancerous tissue was significantly correlated with the histological grade, cell expression PCNA, lymph nodal metastasis and TNM staging of the disease. Patients with TSPAN1 protein overexpression had a significantly shorter survival period than that in patients with TSPAN1 protein negative or weak expression, respectively (P < 0.05). Furthermore, by multivariate analysis, TSPAN1 protein expression demonstrated an independent prognostic factor for human colorectal cancers (P < 0.05, relative risk 0.755; 95% confidence interval 0.302-1.208).

CONCLUSION: The expression of TSPAN1 gene is increased in colorectal carcinoma, suggesting that TSPAN1 might serve as an independent prognostic factor for the colorectal adenocarcinoma patients.

Tspan-1 is a tetraspanin preferentially expressed by mucinous and endometrioid subtypes of human ovarian carcinomas

In many human cancers, tumor progression was found to be associated with an altered expression of tetraspanins, a group of transmembrane adaptor proteins that are implicated in fundamental cellular processes. Although recognized as a characteristic of malignant cells of various origins, Tspan-1 has not yet been characterized in detail due to lack of specific antibodies. We describe the generation of Tspan-1-specific antibodies and immunohistochemical staining of different subtypes of ovarian carcinomas (n=72) that revealed significant differences in Tspan-1 expression that was pronounced in mucinous and endometrioid tumors. The observation that immunoreactivity was focused in intracellular vesicles often concentrated at the luminal sides of glandular structures further supported the assumption that Tspan-1 is involved in secretory pathways. In the group of serous ovarian carcinomas, pronounced expression of Tspan-1 was observed in FIGO stage III C-classified tumors of advanced stages. In summary, our results show that Tspan-1 is an important characteristic of malignant ovarian cancer cells and a potential therapeutic target.

Subcellular forms and biochemical events triggered in human cells by HCV polyprotein expression from a viral vector

To identify the subcellular forms and biochemical events induced in human cells after HCV polyprotein expression, we have used a robust cell culture system based on vaccinia virus (VACV) that efficiently expresses in infected cells the structural and nonstructural proteins of HCV from genotype 1b (VT7-HCV7.9). As determined by confocal microscopy, HCV proteins expressed from VT7-HCV7.9 localize largely in a globular-like distribution pattern in the cytoplasm, with some proteins co-localizing with the endoplasmic reticulum (ER) and mitochondria. As examined by electron microscopy, HCV proteins induced formation of large electron-dense cytoplasmic structures derived from the ER and containing HCV proteins. In the course of HCV protein production, there is disruption of the Golgi apparatus, loss of spatial organization of the ER, appearance of some "virus-like" structures and swelling of mitochondria. Biochemical analysis demonstrate that HCV proteins bring about the activation of initiator and effector caspases followed by severe apoptosis and mitochondria dysfunction, hallmarks of HCV cell injury. Microarray analysis revealed that HCV polyprotein expression modulated transcription of genes associated with lipid metabolism, oxidative stress, apoptosis, and cellular proliferation. Our findings demonstrate the uniqueness of the VT7-HCV7.9 system to characterize morphological and biochemical events related to HCV pathogenesis.