Significance of the association between heparin-binding epidermal growth factor-like growth factor and CD9 in human gastric cancer

Exosomal hsa_circ_000200 as a potential biomarker and metastasis enhancer of gastric cancer via miR-4659a/b-3p/HBEGF axis

BACKGROUND

Exosome, a component of liquid biopsy, loaded protein, DNA, RNA and lipid gradually emerges as biomarker in tumors. However, exosomal circRNAs as biomarker and function mechanism in gastric cancer (GC) are not well understood.

METHODS

Differentially expressed circRNAs in GC and healthy people were screened by database. The identification of hsa_circ_000200 was verified by RNase R and sequencing, and the expression of hsa_circ_000200 was evaluated using qRT-PCR. The biological function of hsa_circ_000200 in GC was verified in vitro. Western blot, RIP, RNA fluorescence in situ hybridization, and double luciferase assay were utilized to explore the potential mechanism of hsa_circ_000200.

RESULTS

Hsa_circ_000200 up-regulated in GC tissue, serum and serum exosomes. Hsa_circ_000200 in serum exosomes showed better diagnostic ability than that of tissues and serum. Combined with clinicopathological parameters, its level was related to invasion depth, TNM staging, and distal metastasis. Functionally, knockdown of hsa_circ_000200 inhibited GC cells proliferation, migration and invasion in vitro, while its overexpression played the opposite role. Importantly, exosomes with up-regulated hsa_circ_000200 promoted the proliferation and migration of co-cultured GC cells. Mechanistically, hsa_circ_000200 acted as a "ceRNA" for miR-4659a/b-3p to increase HBEGF and TGF-β/Smad expression, then promoted the development of GC.

CONCLUSIONS

Our findings suggest that hsa_circ_000200 promotes the progression of GC through hsa_circ_000200/miR-4659a/b-3p/HBEGF axis and affecting the expression of TGF-β/Smad. Serum exosomal hsa_circ_000200 may serve as a potential biomarker for GC.

Helicobacter pylori and Its Role in Gastric Cancer

Gastric cancer is a challenging public health concern worldwide and remains a leading cause of cancer-related mortality. The primary risk factor implicated in gastric cancer development is infection with Helicobacter pylori. H. pylori induces chronic inflammation affecting the gastric epithelium, which can lead to DNA damage and the promotion of precancerous lesions. Disease manifestations associated with H. pylori are attributed to virulence factors with multiple activities, and its capacity to subvert host immunity. One of the most significant H. pylori virulence determinants is the cagPAI gene cluster, which encodes a type IV secretion system and the CagA toxin. This secretion system allows H. pylori to inject the CagA oncoprotein into host cells, causing multiple cellular perturbations. Despite the high prevalence of H. pylori infection, only a small percentage of affected individuals develop significant clinical outcomes, while most remain asymptomatic. Therefore, understanding how H. pylori triggers carcinogenesis and its immune evasion mechanisms is critical in preventing gastric cancer and mitigating the burden of this life-threatening disease. This review aims to provide an overview of our current understanding of H. pylori infection, its association with gastric cancer and other gastric diseases, and how it subverts the host immune system to establish persistent infection.

Integrating Single-cell RNA-seq to construct a Neutrophil prognostic model for predicting immune responses in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the most widely distributed tumor in the world, and its immunotherapy is not practical. Neutrophil is one of a tumor’s most abundant immune cell groups. This research aimed to investigate the complex communication network in the immune microenvironment (TIME) of NSCLC tumors to clarify the interaction between immune cells and tumors and establish a prognostic risk model that can predict immune response and prognosis of patients by analyzing the characteristics of Neutrophil differentiation. Integrated Single-cell RNA sequencing (scRNA-seq) data from NSCLC samples and Bulk RNA-seq were used for analysis. Twenty-eight main cell clusters were identified, and their interactions were clarified. Next, four subsets of Neutrophils with different differentiation states were found, closely related to immune regulation and metabolic pathways. Based on the ratio of four housekeeping genes (ACTB, GAPDH, TFRC, TUBB), six Neutrophil differentiation-related genes (NDRGs) prognostic risk models, including MS4A7, CXCR2, CSRNP1, RETN, CD177, and LUCAT1, were constructed by Elastic Net and Multivariate Cox regression, and patients’ total survival time and immunotherapy response were successfully predicted and validated in three large cohorts. Finally, the causes of the unfavorable prognosis of NSCLC caused by six prognostic genes were explored, and the small molecular compounds targeted at the anti-tumor effect of prognostic genes were screened. This study clarifies the TIME regulation network in NSCLC and emphasizes the critical role of NDRGs in predicting the prognosis of patients with NSCLC and their potential response to immunotherapy, thus providing a promising therapeutic target for NSCLC.

Mechanisms of the Epithelial-Mesenchymal Transition and Tumor Microenvironment in Helicobacter pylori-Induced Gastric Cancer

Helicobacter pylori (H. pylori) is one of the most common human pathogens, affecting half of the world’s population. Approximately 20% of the infected patients develop gastric ulcers or neoplastic changes in the gastric stroma. An infection also leads to the progression of epithelial–mesenchymal transition within gastric tissue, increasing the probability of gastric cancer development. This paper aims to review the role of H. pylori and its virulence factors in epithelial–mesenchymal transition associated with malignant transformation within the gastric stroma. The reviewed factors included: CagA (cytotoxin-associated gene A) along with induction of cancer stem-cell properties and interaction with YAP (Yes-associated protein pathway), tumor necrosis factor α-inducing protein, Lpp20 lipoprotein, Afadin protein, penicillin-binding protein 1A, microRNA-29a-3p, programmed cell death protein 4, lysosomal-associated protein transmembrane 4β, cancer-associated fibroblasts, heparin-binding epidermal growth factor (HB-EGF), matrix metalloproteinase-7 (MMP-7), and cancer stem cells (CSCs). The review summarizes the most recent findings, providing insight into potential molecular targets and new treatment strategies for gastric cancer.

Heparin-Binding Epidermal Growth Factor-Like Growth Factor as a Critical Mediator of Tissue Repair and Regeneration

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a member of the EGF family. It contains an EGF-like domain as well as a heparin-binding domain that allows for interactions with heparin and cell-surface heparan sulfate. Soluble mature HB-EGF, a ligand of human epidermal growth factor receptors 1 and 4, is cleaved from the membrane-associated pro-HB-EGF by matrix metalloproteinase or a disintegrin and metalloproteinase in a process called ectodomain shedding. Signaling through human epidermal growth factor receptors 1 and 4 results in a variety of effects, including cellular proliferation, migration, adhesion, and differentiation. HB-EGF levels increase in response to different forms of injuries as well as stimuli, such as lysophosphatidic acid, retinoic acid, and 17β-estradiol. Because it is widely expressed in many organs, HB-EGF plays a critical role in tissue repair and regeneration throughout the body. It promotes cutaneous wound healing, hepatocyte proliferation after partial hepatectomy, intestinal anastomosis strength, alveolar regeneration after pneumonectomy, neurogenesis after ischemic injury, bladder wall thickening in response to urinary tract obstruction, and protection against ischemia/reperfusion injury to many cell types. Additionally, innovative strategies to deliver HB-EGF to sites of organ injury or to increase the endogenous levels of shed HB-EGF have been attempted with promising results. Harnessing the reparatory properties of HB-EGF in the clinical setting, therefore, may produce therapies that augment the treatment of various organ injuries.

First-in-human study of the anti-HB-EGF antibody U3-1565 in subjects with advanced solid tumors

U3-1565 is a monoclonal antibody directed against heparin-binding epidermal growth factor-like growth factor (HB-EGF), which mediates angiogenesis via induction of vascular endothelial growth factor (VEGF-A). This first-in-human study characterized the safety, tolerability, efficacy, pharmacokinetics, and pharmacodynamics of U3-1565 in subjects with advanced solid tumors. In Part 1 (dose escalation following a modified 3 + 3 design), Cohorts 1-4, U3-1565 was administered at 2, 8, 16, and 24 mg/kg every 3 weeks for Cycle 1 and every 2 weeks thereafter. In Part 1, Cohort 5, and in Part 2 (dose expansion), U3-1565 was administered at 24 mg/kg every week. Thirty-six subjects were enrolled and treated (15 in Part 1; 21 in Part 2). No subject experienced dose limiting toxicity and maximum tolerated dose was not reached. All drug-related events were Grade 1 or 2 in severity, with fatigue and rash predominating. Following treatment with U3-1565, 1 subject with metastatic colorectal cancer experienced partial response and 6 subjects achieved stable disease. Four subjects completed the study main phase (first 12 cycles) and entered the extension phase. Of the 6/36 subjects with high (> 1500 pg/ml) baseline VEGF-A levels, all showed a decrease in VEGF-A (median - 60% [-22% to -97%]). Of the remaining subjects, only 19/30 showed a decrease (median - 18% [-2% to -82%]). Subjects with high VEGF-A baseline levels remained on treatment longer (3/6 entered study extension phase versus 1/30), and were more likely to show disease control (3/6 versus 4/30). In conclusion, U3-1565 demonstrates both proof of mechanism and clinical activity across different tumor types.

Prognostic significance of CD9 expression differs between tumour cells and stromal immune cells, and depends on the molecular subtype of the invasive breast carcinoma

AIMS

CD9, a tetraspanin transmembrane protein, modulates cell motility, migration, and proliferation. The aim of this study was to investigate the prognostic significance of CD9 expression in patients with invasive breast carcinoma (IBC).

METHODS AND RESULTS

CD9 expression was evaluated in tissue microarrays of 1349 IBC samples via immunohistochemistry. CD9 expression in tumour cells (T-CD9 expression) and CD9 expression in stromal immune cells (S-CD9 expression) were analysed separately. T-CD9 expression was observed in 732 (54.3%) cases, and was associated with lymph node metastasis, histological type, lymphovascular invasion, high histological grade, HER2 positivity, a high Ki67 labelling index, and distant metastasis. S-CD9 expression was observed in 833 (61.7%) cases, and was associated with large tumour size, histological type, high histological grade, negative hormone receptors, HER2 positivity, a high Ki67 labelling index, and tumour-infiltrating lymphocytes. Patients with T-CD9 expression had shorter disease-free survival (DFS) than those without T-CD9 expression in the univariate and multivariate analyses. However, S-CD9 expression correlated significantly with a favourable DFS in the univariate and multivariate analyses. In the subgroup analysis, T-CD9 expression and S-CD9 expression were independent markers for DFS in luminal A and luminal B (HER2-negative) subgroups, respectively.

CONCLUSIONS

T-CD9 expression could be a biomarker for poor prognosis in luminal A IBC, whereas S-CD9 expression could be a marker of good prognosis in luminal B (HER2-negative) IBC. Therefore, tumour compartment-specific analyses considering molecular subtypes are necessary to study the prognostic significance of CD9 expression in IBC.

Influence of the HER receptor ligand system on sensitivity to cetuximab and trastuzumab in gastric cancer cell lines

Purpose

Gastric cancer remains a major health concern, and improvement of the therapeutic options is crucial. Treatment with targeted therapeutics such as the EGFR-targeting antibody cetuximab or the HER2-targeting antibody trastuzumab is either ineffective or moderately effective in this disease, respectively. In this study, we analysed the involvement of the HER receptor ligands amphiregulin (AREG), epidermal growth factor (EGF), heparin-binding epidermal growth factor (HB-EGF) and transforming growth factor alpha (TGFα) in the responsiveness of gastric cancer cell lines to cetuximab and trastuzumab.

Methods

A panel of 11 gastric cancer cell lines was characterized for cetuximab and trastuzumab sensitivity, ligand secretion and expression and activation of the HER receptors using WST-1 cell proliferation assays, ELISAs and Western blot analyses. We further investigated the effects of an exogenous ligand application on the cetuximab and trastuzumab sensitivity.

Results

We found no correlation between TGFα secretion and the sensitivity to cetuximab or trastuzumab. For AREG, we confirmed previous results indicating that this ligand is a positive predictor of cetuximab sensitivity. Exogenous HB-EGF was effective in rescuing sensitive cell lines from inhibition of cell proliferation by both, cetuximab and trastuzumab.

Conclusions

Our data indicate that HB-EGF may be a useful marker for the prediction of trastuzumab sensitivity in gastric cancer.

Electronic supplementary material

The online version of this article (doi:10.1007/s00432-016-2308-z) contains supplementary material, which is available to authorized users.

Novel CD9-targeted therapies in gastric cancer

There are 33 human tetraspanin proteins, emerging as key players in malignancy, the immune system, fertilization, cellular signaling, adhesion, morphology, motility, proliferation, and tumor invasion. CD9, a member of the tetraspanin family, associates with and influences a variety of cell-surface molecules. Through these interactions, CD9 modifies multiple cellular events, including adhesion, migration, proliferation, and survival. CD9 is therefore considered to play a role in several stages during cancer development. Reduced CD9 expression is generally related to venous vessel invasion and metastasis as well as poor prognosis. We found that treatment of mice bearing human gastric cancer cells with anti-CD9 antibody successfully inhibited tumor progression via antiproliferative, proapoptotic, and antiangiogenic effects, strongly indicating that CD9 is a possible therapeutic target in patients with gastric cancer. Here, we describe the possibility of CD9 manipulation as a novel therapeutic strategy in gastric cancer, which still shows poor prognosis.

CD9 modulates proliferation of human glioblastoma cells via epidermal growth factor receptor signaling

The tetraspanin CD9 has previously been shown to be involved in various cellular activities, including proliferation and migration. In addition, CD9 has been shown to be associated with epidermal growth factor receptor (EGFR). A common characteristic of glioblastoma multiforme histology is EGFR amplification, which affects signal transduction processes. The anti-proliferative effects of CD9 have been linked to EGFR signaling pathways, including phosphorylation of phosphoinositide-3-kinase (PI3K)/Akt and activation of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated protein kinase (Erk). The present study demonstrated that CD9 decreased the phosphorylation of EGFR at specific sites. In addition, CD9 attenuated EGFR signaling of PI3K/Akt and MAPK/Erk, which was associated with cell growth and proliferation. Conversely, small hairpin RNA-mediated knockdown of CD9 expression enhanced the activation of EGFR signal transduction pathways, including PI3K/Akt and MAPK/Erk. These results suggested that the mechanism underlying CD9-induced suppression of cell proliferation may involve the inhibition of phosphorylation of EGFR and the activity of PI3K/Akt and MAPK/Erk signaling pathways.

Clinical significance and usefulness of soluble heparin binding-epidermal growth factor in gastric cancer

AIM: To evaluate the clinical usefulness of soluble heparin-binding epidermal growth factor (sHB-EGF) as a serum biomarker for gastric cancer (GC).

METHODS: Serum sHB-EGF levels were measured by a commercially available human HB-EGF ELISA Kit and compared among 60 normal controls, 30 high-risk patients, 37 early gastric cancer (EGC), and 30 advanced gastric cancer (AGC) through ANOVA test. Correlations between serum sHB-EGF and clinicopathological features of GC were analyzed through Spearman’s correlation. The diagnostic performance of serum sHB-EGF for GC was evaluated through receiver operating characteristic (ROC) curve and logistic regression analysis.

RESULTS: Serum sHB-EGF levels were significantly higher in AGC group (314.4 ± 127.5 pg/mL) than EGC (165.3 ± 123.2 pg/mL), high-risk (98.7 ± 67.3 pg/mL), and control (94.7 ± 83.6 pg/mL) groups (post-hoc Bonferroni, all P < 0.001), respectively. Serum sHB-EGF levels were also significantly higher in EGC group than high-risk (P = 0.049) and control (P = 0.006) groups. Clinicopathologically, serum sHB-EGF levels closely correlated with depth of invasion (T-stage, γ_s = 0.669, P < 0.001), lymph node metastasis (N-stage, γ_s = 0.407, P = 0.001), and distant metastasis (M-stage, γ_s = 0.261, P = 0.030). ROC curve and logistic regression analysis demonstrated a remarkable diagnostic potential of serum sHB-EGF.

CONCLUSION: Serum sHB-EGF is closely correlated with advanced stage GC and can be a promising serological biomarker for GC.

Crucial involvement of the CCL3-CCR5 axis-mediated fibroblast accumulation in colitis-associated carcinogenesis in mice

Patients with inflammatory bowel diseases often develop colon carcinoma. Combined treatment of azoxymethane (AOM) and dextran sulfate sodium (DSS) recapitulates colitis-associated cancer in mice. AOM/DSS-induced tumor formation was reduced in CCL3- or its specific receptor, CCR5-deficient mice despite the presence of a massive infiltration of inflammatory cells. However, AOM/DSS-induced type I collagen-positive fibroblast accumulation in the colon was reduced in CCL3- or CCR5-deficient mice. This was associated with depressed expression of heparin-binding epidermal growth factor-like growth factor (HB-EGF), which is expressed mainly by fibroblasts. Moreover in vitro, CCL3 induced fibroblasts to proliferate and to enhance HB-EGF expression. Furthermore, CCR5 blockade reduced tumor formation together with reduced fibroblast accumulation and HB-EGF expression, even when administered after the development of multiple colon tumors. Thus, CCL3-CCR5-mediated fibroblast accumulation may be required, in addition to leukocyte infiltration, to induce full-blown colitis-associated carcinogenesis. Our studies shed light on a therapeutic potential of CCR5 antagonist for patients with colitis-associated cancer.

Role of motility-related protein-1 in promoting the development of several types of cancer (Review)

Motility-related protein-1 (CD9), a type of cell surface glycoprotein comprising a four-pass transmembrane domain that forms multimeric complexes with other cell surface proteins, belongs to the tetraspanins family. From previous studies, we know that CD9 is considered to function primarily as a progression and metastasis suppressor in a variety of cancers, including breast, non-small cell lung colon and myeloma. However, an expanding body of literature has shown the contradictory outcome that tetraspanin CD9 is also vital in promoting cancer progression in several types of cancer. This review summarizes the recent studies on CD9 and concludes that it does not always act as a progression and metastasis suppressor. Conversely, in specific cases, CD9 may promote tumor progression through the following three aspects: Facilitating tumor cell transmigration, increasing tumor cell motility and hastening the growth of some cancers. In addition, CD9 appears to be an important marker of cancer stem cells in certain types of tumor.

Prognostic value of NF-κB, CD9, and VEGF in gastrointestinal stromal tumors

AIM OF THE STUDY

Gastrointestinal stromal tumors (GISTs) are the most frequent mesenchymal tumors of the gastrointestinal system. We aimed to determine whether nuclear transcription factor κB (NF-κB), CD9 and vascular endothelial growth factor (VEGF) have prognostic value in patients with GIST.

MATERIAL AND METHODS

Thirty-five patients with GIST, who were diagnosed in the Pathology Department of Erciyes University, were included in the study. Cases were classified based on the 2002 NIH consensus. CD9, VEGF, and NF-κB immunohistochemistry were applied to GIST cases positive for CD117 and CD34, which are used to evaluate GISTs immunohistochemically.

RESULTS

Although there are no statistically significant differences between NF-κB (p = 0.329), CD9 (p = 0.269), and VEGF (p = 0.372) and risk groups, 79.22% of cases that stained positive for NF-κB, 81% of cases that stained positive for CD9, and 80% of cases that stained positive of VEGF were in the high risk group.

CONCLUSIONS

It was found that NF-κB, CD9, and VEGF, which are important in predicting behaviors of other malign tumors, were expressed at high rates in high risk group GISTs. This can be used to determine prognosis with tumor diameter, mitosis rate under 50 BBS, Ki-67 proliferation index and other parameters.

Helicobacter pyloriγ-glutamyl transpeptidase: A formidable virulence factor

Helicobacter pylori (H. pylori) produce an enzyme known as γ-glutamyl transpeptidase (HpGGT) that is highly conserved and common to all strains. HpGGT has been gaining increasing attention as an important virulence factor of the bacterium, having been demonstrated to be an important colonization factor in several animal models and has also recently been strongly associated with the development of peptic ulcer disease. From the results of various independent researcher groups, it is clear that HpGGT acts through several pathways to damage gastric epithelial cells including the induction of apoptosis and cell cycle arrest, production of reactive oxygen species leading to DNA damage, promotion of inflammation by increasing cyclooxygenase-2 and interleukin-8 expression, and upregulation of heparin-binding epidermal growth factor-like growth factor resulting in cell survival and proliferation. In addition, the potential role of HpGGT in promoting gastric carcinogenesis will also be discussed in this review. Apart from affecting the gastric epithelium, HpGGT also has immunomodulatory actions on host immune cells where it displays an antiproliferative effect on T cells by inducing cell cycle arrest and also works with other H. pylori virulence factors to skew dendritic cells towards a tolerogenic phenotype, possibly contributing to the persistence of the pathogen in the gastric mucosa.

Nuclear translocation of the cytoplasmic domain of HB-EGF induces gastric cancer invasion

Background

Membrane-anchored heparin-binding epidermal growth factor-like growth factor (proHB-EGF) yields soluble HB-EGF, which is an epidermal growth factor receptor (EGFR) ligand, and a carboxy-terminal fragment of HB-EGF (HB-EGF-CTF) after ectodomain shedding. We previously reported that HB-EGF-CTF and unshed proHB-EGF which has the cytoplasmic domain of proHB-EGF (HB-EGF-C), translocate from the plasma membrane to the nucleus and regulate cell cycle after shedding stimuli. However, the significance of nuclear exported HB-EGF-C in human gastric cancer is unclear.

Methods

We investigated the relationship between intracellular localization of HB-EGF-C and clinical outcome in 96 gastric cancer patients treated with gastrectomy. Moreover, we established stable gastric cancer cell lines overexpressing wild-type HB-EGF (wt-HB-EGF) and mutated HB-EGF (HB-EGF-mC), which prevented HB-EGF-C nuclear translocation after shedding. Cell motility between these 2 gastric cancer cell lines was investigated using a transwell invasion assay and a wound healing assay.

Results

Of the 96 gastric cancer cases, HB-EGF-C immunoreactivity was detected in both the nucleus and cytoplasm in 19 cases (19.8 %) and in the cytoplasm only in 25 cases (26.0 %). The nuclear immunoreactivity of HB-EGF-C was significantly increased in stage pT3/4 tumors compared with pT1/2 tumors (T1/2 vs. T3/4: 11.1 % vs. 36.4 %, P < 0.01). The growth of wt-HB-EGF- and HB-EGF-mC-expressing cells significantly increased compared with control cells, but the growth of HB-EGF-mC-expressing cells was significantly decreased compared with wt-HB-EGF-expressing cells. Gastric cancer cell invasion obviously increased in wt-HB-EGF-expressing cells, but invasion in HB-EGF-mC-expressing cells showed a slight increase compared with control cells. Moreover, wt-HB-EGF overexpression increased the effectiveness of wound healing, but had no significant effect in HB-EGF-mC-expressing cells.

Conclusions

Both the function of HB-EGF as an EGFR ligand and a novel signal for HB-EGF-C nuclear translocation induce gastric cancer growth, whereas HB-EGF-C nuclear translocation independently plays a critical role in gastric cancer invasion. The present study demonstrated that HB-EGF-C nuclear translocation might be crucial in gastric cancer invasion. HB-EGF-C nuclear translocation may offer a prognostic marker and a new molecular target for gastric cancer therapy.

Genes associated with prognosis after surgery for malignant pleural mesothelioma promote tumor cell survival in vitro

Background

Mesothelioma is an aggressive neoplasm with few effective treatments, one being cytoreductive surgery. We previously described a test, based on differential expression levels of four genes, to predict clinical outcome in prospectively consented mesothelioma patients after surgery. In this study, we determined whether any of these four genes could be linked to a cancer relevant phenotype.

Methods

We conducted a high-throughput RNA inhibition screen to knockdown gene expression levels of the four genes comprising the test (ARHGDIA, COBLL1, PKM2, TM4SF1) in both a human lung-derived normal and a tumor cell line using three different small inhibitory RNA molecules per gene. Successful knockdown was confirmed using quantitative RT-PCR. Detection of statistically significant changes in apoptosis and mitosis was performed using immunological assays and quantified using video-assisted microscopy at a single time-point. Changes in nuclear shape, size, and numbers were used to provide additional support of initial findings. Each experiment was conducted in triplicate. Specificity was assured by requiring that at least 2 different siRNAs produced the observed change in each cell line/time-point/gene/assay combination.

Results

Knockdown of ARHGDIA, COBLL1, and TM4SF1 resulted in 2- to 4-fold increased levels of apoptosis in normal cells (ARHGDIA only) and tumor cells (all three genes). No statistically significant changes were observed in apoptosis after knockdown of PKM2 or for mitosis after knockdown of any gene.

Conclusions

We provide evidence that ARHGDIA, COBLL1, and TM4SF1 are negative regulators of apoptosis in cultured tumor cells. These genes, and their related intracellular signaling pathways, may represent potential therapeutic targets in mesothelioma.

CD9P-1 expression correlates with the metastatic status of lung cancer, and a truncated form of CD9P-1, GS-168AT2, inhibits in vivo tumour growth

BACKGROUND

Loss of CD9 expression has been correlated with a higher motility and metastatic potential of tumour cells originating from different organs. However, the mechanism underlying this loss is not yet understood.

METHODS

We produced a truncated form of partner 1 of CD9 (CD9P-1), GS-168AT2, and developed a new monoclonal antibody directed towards the latter. We measured the expression of CD9 and CD9P-1 in human lung tumours (hLTs), and monitored the level of CD9 in NCI-H460, in vitro and in vivo, in the presence and absence of GS-168AT2.

RESULTS

Loss of CD9 is inversely related to the expression of CD9P-1, which correlates with the metastatic status of hLT (n=55). In vitro, GS-168AT2 is rapidly internalised and degraded at both the membrane and cytoplasm of NCI-H460, and this correlates with the association of GS-168AT2 with both CD9 and CD81. Intraperitoneal injections of GS-168AT2 in NCI-H460-xenografted Nude mice led to drastic inhibition of tumour growth, as well as to the downregulation of CD9, but not of CD81, in the tumour core.

CONCLUSION

These findings show for the first time that CD9P-1 expression positively correlates with the metastatic status of hLT, and that the upregulation of CD9P-1 expression could be one of the mechanisms underlying the loss of CD9 in solid tumours. Our study also reveals that, under certain conditions, loss of CD9 could be a tumour growth-limiting phenomenon rather than a tumour growth-promoting one.

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.

A novel therapeutic strategy with anti-CD9 antibody in gastric cancers

BACKGROUND

CD9 is a member of the tetraspanins, and has been shown to be involved in a variety of cellular activities such as motility, cell signaling, proliferation, adhesion, and metastasis. However, very little is known about the involvement of CD9 in the process of development of primary tumors. In the present study, we investigated whether anti-CD9 monoclonal antibody (ALB6) has antitumor effects in human gastric cancer cell xenografts.

METHODS

Human gastric cancer cell lines (MKN-28) (5 x 10(6) cells/animal) were inoculated subcutaneously into the dorsal region of SCID mice (five mice in each group). After a tumor was visualized, animals were assigned to either the ALB6 treatment group or the control IgG treatment group (100 microg/body/time, intravenous, three times per week. Day 1, 4, and 7 of first week). Then tumor volumes were monitored every day. Proliferation of tumor was analyzed by 5-bromo-2'-deoxyuridine (BrdU) immunostaining, apoptosis was determined by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) methods, and angiogenesis was assessed by counting the number of CD34-positive endothelial cells.

RESULTS

Tumor volume was significantly suppressed (1,682 +/- 683 mm(3) versus 4,507 +/- 1,012 mm(3); P = 0.049), the BrdU labeling indexes were significantly decreased (10.9 +/- 1.1% versus 17.2 +/- 1.4%; P = 0.009), the apoptotic indexes were significantly increased (1.98 +/- 0.48% versus 0.72 +/- 0.09%; P = 0.034), and tumor microvessel densities were significantly suppressed (671,922 +/- 34,505 pixels/mm(2) versus 1,135,043 +/- 36,086 pixels/mm(2); P = 0.037) in the ALB6 treatment group compared with the control IgG treatment group.

CONCLUSIONS

These results suggest that administration of anti-CD9 antibody to mice bearing human gastric cancer cells successfully inhibits tumor progression via antiproliferative, proapoptotic, and antiangiogenetic effects.

The anti-tumour agent, cisplatin, and its clinically ineffective isomer, transplatin, produce unique gene expression profiles in human cells

Cisplatin is a DNA-damaging anti-cancer agent that is widely used to treat a range of tumour types. Despite its clinical success, cisplatin treatment is still associated with a number of dose-limiting toxic side effects. The purpose of this study was to clarify the molecular events that are important in the anti-tumour activity of cisplatin, using gene expression profiling techniques. Currently, our incomplete understanding of this drug's mechanism of action hinders the development of more efficient and less harmful cisplatin-based chemotherapeutics. In this study the effect of cisplatin on gene expression in human foreskin fibroblasts has been investigated using human 19K oligonucleotide microarrays. In addition its clinically inactive isomer, transplatin, was also tested. Dualfluor microarray experiments comparing treated and untreated cells were performed in quadruplicate. Cisplatin treatment was shown to significantly up- or down-regulate a consistent subset of genes. Many of these genes responded similarly to treatment with transplatin, the therapeutically inactive isomer of cisplatin. However, a smaller proportion of these transcripts underwent differential expression changes in response to the two isomers. Some of these genes may constitute part of the DNA damage response induced by cisplatin that is critical for its anti-tumour activity. Ultimately, the identification of gene expression responses unique to clinically active compounds, like cisplatin, could thus greatly benefit the design and development of improved chemotherapeutics.

The tetraspanin CD9 modulates epidermal growth factor receptor signaling in cancer cells

CD9 is a member of the tetraspanins, and has been shown to be involved in a variety of cellular activities such as migration, proliferation, and adhesion. In addition, it has been known that CD9 can associate with other proteins. Here we demonstrated the physical and functional association of CD9 with epidermal growth factor receptor (EGFR) on MKN-28 cells. Double-immunofluorescent staining and immunoprecipitation demonstrated the complex formation of CD9-EGFR and CD9-beta(1) integrin, and that both complexes are colocalized on the cell surface especially at the cell-cell contact site. Anti-CD9 monoclonal antibody ALB6 induced a dotted or patch-like aggregation pattern of both CD9-EGFR and CD9-beta(1) integrin. The internalization of EGFR after EGF-stimulation was significantly enhanced by the treatment with ALB6. CD9 can associate with EGFR in hepatocellular carcinoma cells (HepG2/CD9) and Chinese hamster ovary cancer cells (CHO-HER/CD9), which were transfected with pTJ/human EGFR/CD9. Furthermore expression of CD9 specifically attenuated EGFR signaling in CHO-HER/CD9 cells through the down regulation of surface expression of EGFR. These results suggest that CD9 might have an important role that attenuates EGFR signaling. Therefore, CD9 not only associates EGFR but also a new regulator, which may affect EGF-induced signaling in cancer cells.

ADAM28 is overexpressed in human non-small cell lung carcinomas and correlates with cell proliferation and lymph node metastasis

ADAM (a disintegrin and metalloproteinases) are a recently discovered gene family of proteins with sequence similarity to the reprolysin family of snake venom metalloproteinases, and about one-third of the family members have the catalytic site consensus sequence in their metalloproteinase domains. We screened the mRNA expression of 11 different ADAM species with putative metalloproteinase activity in human non-small cell lung carcinomas by RT-PCR, and found that prototype membrane-anchored ADAM28 (ADAM28m) and secreted ADAM28 (ADAM28s) are predominantly expressed in the carcinoma tissues. Real-time quantitative PCR demonstrated that the expression levels of ADAM28m and ADAM28s are significantly 16.8-fold and 9.0-fold higher in the carcinomas than in the non-carcinoma tissues, respectively. In addition, the expression levels of ADAM28m and ADAM28s were significantly higher in the carcinomas with >30 mm in diameter than in those < or =30 mm. The expression levels were also significantly higher in the carcinomas with lymph node metastasis than in those without metastasis. MIB1-positive cell index of the carcinomas had a direct correlation with the expression levels of ADAM28m and ADAM28s (r = 0.667, p < 0.001 and r = 0.535, p < 0.01, respectively). In situ hybridization and immunohistochemistry demonstrated that ADAM28 is expressed predominantly in the carcinoma cells. Immunoblot analysis showed the activated form of ADAM28 in the carcinoma tissues. These data demonstrate for the first time that ADAM28 is overexpressed and activated in human non-small cell lung carcinomas, and suggest the possibility that ADAM28 plays a role in cell proliferation and progression of the human lung carcinomas.

Clinical significance of heparin-binding epidermal growth factor-like growth factor and a disintegrin and metalloprotease 17 expression in human ovarian cancer

PURPOSE

Lysophosphatidic acid, which is enriched in the peritoneal fluid of ovarian cancer patients, plays a key role in the progression of ovarian cancer. Lysophosphatidic acid can generate epidermal growth factor receptor (EGFR) signal transactivation involving processing of EGFR ligands by ADAM (a disintegrin and metalloprotease) family metalloproteases. We aimed to investigate the clinical significance of EGFR ligands and ADAM family in the lysophosphatidic acid-induced pathogenesis of ovarian cancer.

EXPERIMENTAL DESIGN

We examined the expression of EGFR ligands and ADAM family members in 108 patients with normal ovaries or ovarian cancer, using real-time PCR, immunohistochemistry, and in situ hybridization, and analyzed the clinical roles of these molecules. Statistical analyses of these data were done using the Mann-Whitney test, Kaplan-Meier method, or Spearman's correlation analysis.

RESULTS

Large differences in expression were found for heparin-binding EGF-like growth factor (HB-EGF) and other EGFR ligands and for ADAM 17 and other ADAM family members. HB-EGF expression was significantly increased in advanced ovarian cancer compared with that in normal ovaries (P < 0.01). HB-EGF expression was significantly associated with the clinical outcome (P < 0.01). ADAM 17 expression was significantly enhanced in both early and advanced ovarian cancer compared with that in normal ovaries (both P < 0.01), although it had no clinical significance in the progression-free survival. HB-EGF expression was significantly correlated with ADAM 17 expression (gamma = 0.437, P < 0.01).

CONCLUSIONS

Our findings suggest that HB-EGF and ADAM 17 contribute to the progression of ovarian cancer and that HB-EGF plays a pivotal role in the aggressive behavior of a tumor in ovarian cancer.

Androgens induce CD-9 in human prostate tissue

Based on microarray analyses of LNCaP and LNCaP-r prostatic cell-lines we tentatively identified CD-9 as an androgen sensitive protein. This prompted us to characterize the androgen sensitivity and the correlation to malignancy of CD-9 at the protein level. Using Western blot, RT-PCR and immunohistochemistry the expression of CD-9 was analysed in LNCaP cells stimulated during increasing time by the synthetic androgen R1881 and also in 88 specimens of human prostate cancer tissues. Expression of CD-9 was induced by R1881 in LNCaP. CD-9 was immunolocalized in human prostate tissue sections representing non-malignant tissue as well as tumour areas. In non-malignant glands CD-9 immunoreactivity was observed at the apical and lateral cell borders of luminal epithelial cells. Basal epithelial cells were largely unstained. In tumour areas CD-9 staining intensity was variable and apparently not related to primary Gleason grade. In prostate tissue from a patient under androgen ablation therapy no staining was observed in luminal epithelial cells or in the tumour areas, but some staining was observed in basal epithelial cells. CD-9 is regulated by androgens in LNCaP and present in human prostate specimens. The expression is variable and changes in expression levels. These and earlier studies using other tissues indicate that CD-9 and its cellular localization could have an important role in prostate cancer cell development.

Validation of genomics-based prognostic tests in malignant pleural mesothelioma

PURPOSE

Malignant pleural mesothelioma (MPM) is a highly lethal neoplasm with limited pretreatment prognostication strategies. In this report, we examine the accuracy of a previously proposed prognostic test in an independent cohort of MPM patients. This test uses simple ratios of gene expression levels to provide a novel prognostication scheme.

EXPERIMENTAL DESIGN

Gene expression data using high-density oligonucleotide microarrays (approximately 22,000 genes) were obtained for a new cohort of human MPM tumors from patients undergoing similar treatments (n = 39). The relative expression levels for specific genes were also determined using real-time quantitative reverse transcription-PCR. We also used a subset of these tumors associated with widely divergent patient survival (n = 23) as a training set to identify new treatment-specific candidate prognostic molecular markers and gene ratio-based prognostic tests. The predictive nature of these newly discovered markers and gene ratio-based prognostic tests were then examined in an independent group of tumors (n = 52) using microarray data and quantitative reverse transcription-PCR.

RESULTS

Previously described MPM prognostic genes and gene ratio-based prognostic tests predicted clinical outcome in 39 independent MPM tumor specimens in a statistically significant manner. Newly discovered treatment-specific prognostic genes and gene ratio-based prognostic tests were highly accurate and statistically significant when examined in an independent group of 52 tumors from patients undergoing similar treatment.

CONCLUSIONS

The data support the use of gene ratios in translating gene expression data into easily reproducible, statistically validated clinical tests for the prediction of outcome in MPM.

Regenerative and therapeutic effects of heparin-binding epidermal growth factor-like growth factor on diabetes by gene transduction through retrograde pancreatic duct injection of adenovirus vector

OBJECTIVES

In the adult pancreas, pre-existing beta cells, stem cells, and endocrine progenitor cells residing in the duct lining are considered important sources for beta-cell regeneration. A member of the epidermal growth factor (EGF) family, heparin binding (HB)-EGF, may promote this process. We examined whether HB-EGF gene transduction into duct cells could promote beta-cell regeneration.

METHODS

We administered an HB-EGF adenovirus vector construct to male Institute of Cancer Research mice by retrograde injection through the pancreatic duct. We also performed HB-EGF gene transduction into cultured duct cells.

RESULTS

On immunohistochemical and histomorphometric analysis of the experimental group, insulin-positive cells differentiated from duct cells, and the 5-bromo-2-deoxyuridine labeling index of beta cells was significantly increased. beta-cell mass was also increased, and the glucose tolerance of diabetic mice was improved at 12 weeks after injection. Using cultured pancreatic duct cells, we confirmed that HB-EGF gene transduction induced both insulin gene expression and insulin production by these cells.

CONCLUSIONS

These results indicate that HB-EGF gene transduction into adult pancreatic duct cells not only promotes the proliferation of pre-existing beta cells but also leads to beta-cell differentiation from duct cells, and the resulting increase in beta-cell mass improves glucose tolerance.

CD9-mediated activation of the p46 Shc isoform leads to apoptosis in cancer cells

CD9, a member of the tetraspanin family, has been shown to be involved in a range of cellular activities, including migration, proliferation and adhesion, but the molecular mechanisms by which it mediates such events is unclear. Here, we found that anti-CD9 monoclonal antibody ALB6 inhibited cell proliferation, reduced cell viability and induced not only morphological changes specific to apoptosis but also molecular changes, as evidenced by TUNEL and annexin-V staining. For the possible mechanism of ALB6-induced apoptosis, ALB6 activated the c-Jun NH2-terminal kinase/stress-activated protein kinase (JNK/SAPK) and p38 mitogen-activated-protein kinase (MAPK) within 5-15 minutes, as well as caspase-3 within 24-48 hours. It is noteworthy that ALB6 induced tyrosine phosphorylation of the p46 Shc isoform specifically and that the overexpression of its dominant-negative form completely suppressed the ALB6-induced activation of JNK/SAPK, p38 MAPK and caspase-3, resulting in the inhibition of apoptotic cell death. These results suggest that CD9 might regulate apoptosis through the specialized signals in human cancer cell lines.

HB-EGF is a potent inducer of tumor growth and angiogenesis

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) has been shown to stimulate the growth of a variety of cells in an autocrine or paracrine manner. Although HB-EGF is widely expressed in tumors compared with normal tissue, its contribution to tumorigenicity is unknown. HB-EGF can be produced as a membrane-anchored form (pro-HB-EGF) and later processed to a soluble form (s-HB-EGF), although a significant amount of pro-HB-EGF remains uncleaved on the cell surface. To understand the roles of two forms of HB-EGF in promoting tumor growth, we have studied the effects of HB-EGF expression in the process of tumorigenesis using in vitro and in vivo systems. We demonstrate here that in EJ human bladder cancer cells containing a tetracycline-regulatable s-HB-EGF or pro-HB-EGF expression system, s-HB-EGF expression increased their transformed phenotypes, including growth rate, colony-forming ability, and activation of cyclin D1 promoter, as well as induction of vascular endothelial growth factor in vitro. Moreover, s-HB-EGF or wild-type HB-EGF induced the expression and activities of the metalloproteases, MMP-9 and MMP-3, leading to enhanced cell migration. In vivo studies also demonstrated that tumor cells expressing s-HB-EGF or wild-type HB-EGF significantly enhanced tumorigenic potential in athymic nude mice and exerted an angiogenic effect, increasing the density and size of tumor blood vessels. However, cells expressing solely pro-HB-EGF did not exhibit any significant tumorigenic potential. These findings establish s-HB-EGF as a potent inducer of tumor growth and angiogenesis and suggest that therapeutic intervention aimed at the inhibition of s-HB-EGF functions may be useful in cancer treatment.

CD9 expression in gastric cancer and its significance

BACKGROUND

The tetraspanin transmembrane protein CD9 is known to be involved in cell adhesion, proliferation, and cell motility. Previous studies have reported that reduced expression of CD9 is related to aggressive behavior of cancer cells. However, the cause-and-effect relationship between the CD9 expression level and the state of malignancy remains unclear. Here, we investigated the connection between the CD9 expression level and the state of malignancy in gastric cancers.

MATERIALS AND METHODS

The expression of CD9 was examined in primary and metastatic gastric carcinoma tissues. In total, specimens from 78 patients were used for immunohistological staining and specimens from 57 patients were subjected to Northern blotting. Paired samples of tumor/normal tissues obtained from five cases of gastric cancer were used for Western blotting.

RESULTS

CD9 expression was observed at both the message level and the protein level in primary gastric carcinoma tissues, lymph node metastatic tissues, and peritoneal dissemination tissues. Contrary to previous reports for other cancers, CD9 expression was intensified in cancerous areas of gastric cancers in comparison with noncancerous areas in the same patient. When analyzed by the malignancy status based on the clinicopathological diagnosis, there was a tendency that CD9 expression was observed in severe vessel invasion, active lymph node metastasis, and advanced stage.

CONCLUSIONS

CD9 expression was rather intensified in gastric cancer tissue in comparison with normal tissues. CD9 expression was more prominent in advanced gastric cancer.

Prevention of gastric cancer by Helicobacter pylori eradication

The evidence supporting the important role of Helicobacter pylori causing gastric cancer is getting stronger. The mechanisms by which H. pylori can influence the progression to severe changes in the gastric mucosa are under investigation. An increased gastric epithelial cell proliferation has been observed in individuals infected with H. pylori. This lifelong increased cell turnover is deemed to be a major risk factor for increased mutational changes and may lead to the development of gastric cancer. Successful eradication of H. pylori infection induces the healing of the gastritis and a significant decrease in gastric epithelial cell proliferation. Nevertheless, it is right now unknown at which time the point of no return, meaning at which time an eradication therapy leads to a benefit for the individual to prevent gastric cancer, has been reached. Therefore the major question that arises is to whom an eradication therapy should be offered to prevent gastric cancer. A general elimination of the infection might be worthwhile, but seems to be unrealistic now because of the high prevalence of the infection and the missing of a vaccine. This review reflects possible mechanisms of gastric cancer development induced by chronic H. pylori infection and recent investigational trials for prevention of gastric cancer by H. pylori eradication therapy will be discussed.