Adhesion Of Gastric Cancer Cells Research Articles

Aldo-keto Reductase 1B10 Restrains Cell Migration, Invasion, and Adhesion of Gastric Cancer via Regulating Integrin Subunit Alpha 5.

Gastric cancer is a prevalent malignancy with unfavorable prognosis partially resulting from its high metastasis rate. Clarifying the molecular mechanism of gastric cancer occurrence and progression for improvement of therapeutic efficacy and prognosis is needed. The study tended to delineate the role and regulatory mechanism of aldo-keto reductase 1B10 (AKR1B10) in gastric cancer progression. The relationship of AKR1B10 expression with survival rate in gastric cancer was analyzed through Kaplan-Meier analysis. The mRNA levels of AKR1B10 and integrin subunit alpha 5 (ITGA5) in gastric cancer tissues and cell lines were measured by real-time quantitative polymerase chain reaction. Protein levels of AKR1B10 and integrin subunit alpha 5 were assayed via western blot. The molecular relationship between AKR1B10 and ITGA5 was analyzed by co-immunoprecipitation assay. Cell viability was assayed through Cell Counting Kit-8, invasion and migration of tumor cells was assessed through wound healing and transwell assays. Transwell assay was utilized to detect invasion. The adhesion of gastric cancer cells was detected using cell adhesion assays. The results unveiled that integrin subunit alpha 5 was upregulated, while AKR1B10 was downregulated in gastric cancer tissues and cells. Overexpressing AKR1B10 hindered gastric cancer cell proliferation, migration, invasion and adhesion. It was striking that we certified the inhibitory effect of AKR1B10 on integrin subunit alpha 5 expression and their (AKR1B10 and ITGA5)) negative relationship via bioinformatics method, real-time quantitative polymerase chain reaction, and co-immunoprecipitation assays. Via rescue experiments, it was concluded that AKR1B10 served as tumor suppressor potentially by ITGA5 expression in gastric cancer. Our results indicated that AKR1B10 inhibited migration, invasion, and adhesion of gastric cancer cells via modulation of ITGA5.

An Intrabody against B-Cell Receptor-Associated Protein 31 (BAP31) Suppresses the Glycosylation of the Epithelial Cell-Adhesion Molecule (EpCAM) via Affecting the Formation of the Sec61-Translocon-Associated Protein (TRAP) Complex.

The epithelial cell-adhesion molecule (EpCAM) is hyperglycosylated in carcinoma tissue and the oncogenic function of EpCAM primarily depends on the degree of glycosylation. Inhibiting EpCAM glycosylation is expected to have an inhibitory effect on cancer. We analyzed the relationship of BAP31 with 84 kinds of tumor-associated antigens and found that BAP31 is positively correlated with the protein level of EpCAM. Triple mutations of EpCAM N76/111/198A, which are no longer modified by glycosylation, were constructed to determine whether BAP31 has an effect on the glycosylation of EpCAM. Plasmids containing different C-termini of BAP31 were constructed to identify the regions of BAP31 that affects EpCAM glycosylation. Antibodies against BAP31 (165-205) were screened from a human phage single-domain antibody library and the effect of the antibody (VH-F12) on EpCAM glycosylation and anticancer was investigated. BAP31 increases protein levels of EpCAM by promoting its glycosylation. The amino acid region from 165 to 205 in BAP31 plays an important role in regulating the glycosylation of EpCAM. The antibody VH-F12 significantly inhibited glycosylation of EpCAM which, subsequently, reduced the adhesion of gastric cancer cells, inducing cytotoxic autophagy, inhibiting the AKT-PI3K-mTOR signaling pathway, and, finally, resulting in proliferation inhibition both in vitro and in vivo. Finally, we clarified that BAP31 plays a key role in promoting N-glycosylation of EpCAM by affecting the Sec61 translocation channels. Altogether, these data implied that BAP31 regulates the N-glycosylation of EpCAM and may represent a potential therapeutic target for cancer therapy.

Retracted] Inhibition airway remodeling and transforming growth factor‑β1/Smad signaling pathway by astragalus extract in asthmatic mice.

Following the publication of this paper, it was drawn to the Editor's attention by a concerned reader that the P‑smad2 western blotting data shown in Fig.7 were strikingly similar to data appearing in different form (namely, the bands appeared in the reverse orientation) in Fig.4A in another article [LvZ‑D, NaD, LiuF‑N, Du Z‑M, Sun Z, Li Z, MaX‑Y, WangZ‑N and XuH‑M: Induction of gastric cancer cell adhesion through transforming growth factor‑beta1‑mediated peritoneal fibrosis. J Exp Clin Cancer Res29: 139, 2010], which was written by mostly different authors at different research institutes (the author Zheng‑Hai Qu did appear as an author on both papers). Owing to the fact that the contentious data in the above article had already been published prior to its submission to International Journal of Molecular Medicine, and due to a lack of overall confidence in the presented data, the Editor has decided that this paper should be retracted from the Journal. After having been in contact with the authors, they accepted the decision to retract the paper. The Editor apologizes to the readership for any inconvenience caused. [International Journal of Molecular Medicine 29: 564‑568, 2012; DOI: 10.3892/ijmm.2011.868].

Retracted] TGF‑β1 induces peritoneal fibrosis by activating the Smad2 pathway in mesothelial cells and promotes peritoneal carcinomatosis.

Following the publication of this paper, it was drawn to the Editor's attention by a concerned reader that the fluorescence microscopy data shown in Fig.6A and B were strikingly similar to data appearing in different form in Fig.7 in a previously published paper [LvZ‑D, NaD, LiuF‑N, DuZ‑M, SunZ, Li Z, MaX‑Y, WangZ‑N and XuH‑M: Induction of gastric cancer cell adhesion through transforming growth factor‑beta1‑mediated peritoneal fibrosis. J Exp Clin Cancer Res29: 139, 2010], which featured some of the same authors, although the data were shown to portray results obtained under different experimental conditions. Furthermore, the data in Fig.7A for the 'TGF‑β1' and the 'TGF‑β1+siRNAcon' experiments contained an overlapping section, such that these data appeared to have been derived from the same original source, even though they were intended to show the results from differently performed experiments. Owing to the fact that the contentious data in the above article had already been published prior to its submission to International Journal of Molecular Medicine, and due to a lack of overall confidence in the presented data, the Editor has decided that this paper should be retracted from the Journal. After having been in contact with the authors, they accepted the decision to retract the paper. The Editor apologizes to the readership for any inconvenience caused. [International Journal of Molecular Medicine 29: 373‑379, 2012; DOI: 10.3892/ijmm.2011.852].

Adhesion of Gastric Cancer Cells to the Enteric Nervous System: Comparison between the Intestinal Type and Diffuse Type of Gastric Cancer.

Simple SummaryGastric cancer is one of the leading cause of cancer-related deaths worldwide. The role of the enteric nervous system, a component of the tumor micro-environment in digestive cancers is of growing interest, since enteric neurons may be a route for cancer dissemination. The aim of this study was to investigate the adhesion of the gastric cancer cells to the neurons of the enteric nervous system. We showed that enteric neurons were a privileged site of gastric cancer cell adhesion, particularly in diffuse-type gastric cancer cell lines. We showed that this phenomenon was partially mediated by N-Cadherin, an adhesion protein whose blockade resulted in a dramatic decrease in adhesion ability. These results support the role of enteric neurons as a potential route for cancer cells dissemination, particularly in diffuse-type gastric cancer.Background: Gastric cancer (GC) is the third leading cause of cancer-related deaths worldwide. The enteric nervous system (ENS) has been suggested to be involved in cancer development and spread. Objective: To analyze the GC cell adhesion to the ENS in a model of co-culture of gastric ENS with GC cells. Methods: Primary culture of gastric ENS (pcgENS), derived from a rat embryo stomach, was developed. The adhesion of GC cells to pcgENS was studied using a co-culture model. The role of N-Cadherin, a cell-adhesion protein, was evaluated. Results: Compared to intestinal-type GC cells, the diffuse-type GC cancer cells showed higher adhesion to pcgENS (55.9% ± 1.075 vs. 38.9% ± 0.6611, respectively, p < 0.001). The number of diffuse-type GC cells adherent to pcgENS was significantly lower in neuron-free pcgENS compared to neuron-containing pcgENS (p = 0.0261 and 0.0329 for AGS and MKN45, respectively). Confocal microscopy showed that GC cells adhere preferentially to the neurons of the pcgENS. N-Cadherin blockage resulted in significantly decreased adhesion of the GC cells to the pcgENS (p < 0.01). Conclusion: These results suggest a potential role of enteric neurons in the dissemination of GC cells, especially of the diffuse-type, partly through N-Cadherin.

Novel roles of LSECtin in gastric cancer cell adhesion, migration, invasion, and lymphatic metastasis

Liver and lymph node sinusoidal endothelial cell C-type lectin (LSECtin) plays an important regulatory role in a variety of diseases, including tumors. However, the underlying mechanism of LSECtin in gastric cancer (GC) remains largely unknown. In our research, LSECtin promoted the adhesion and invasion of GC cells, and was involved in lymphatic metastasis of GC cells. Mechanistically, LSECtin promoted the adhesion, proliferation and migration of GC cells by downregulating STAT1 expression. The circular RNA circFBXL4, which is regulated by LSECtin, sponges the microRNA miR-146a-5p to regulate STAT1 expression. The promotion of GC cell proliferation, migration and invasion mediated by LSECtin was largely inhibited by circFBXL4 overexpression or miR-146a-5p silencing. Moreover, in its role as a transcription factor, STAT1 modulated the expression of FN1 and CHD4. In conclusion, LSECtin might be involved in the lymphatic metastasis of GC by upregulating the expression of FN1 and CHD4 via the circFBXL4/miR-146a-5p/STAT1 axis, possibly indicating a newly discovered pathogenic mechanism.

Poria Acid, Triterpenoids Extracted from Poria cocos, Inhibits the Invasion and Metastasis of Gastric Cancer Cells.

Background: Poria cocos (P. cocos) is an important medicinal fungus in traditional Chinese medicine. Poria acid (PA), a triterpenoid compound, is an effective component of traditional Chinese medicine P. cocos. This experiment investigated the anti-gastric cancer biological activity of PA in vitro. Methods: The effect of PA on the viability of gastric cancer cells was detected by the thiazolyl blue (MTT) assay. Cell adhesion assays were used to detect changes in the adhesion of cells treated after PA (0, 20, 40, and 80 µmol/L). The ability of cell invasion and migration were detected by Transwell assays and wound healing assays. A high-content imaging system was used to dynamically record the motility of the gastric cancer cells after PA (0, 20, 40, and 80 µmol/L) treatment. Western blotting was used to detect the expression of epithelial–mesenchymal transformation (EMT), invasion and migration related proteins. Results: The MTT assay showed that the proliferation of gastric cancer cells was significantly inhibited after PA treatment. Cell adhesion experiments showed that the adhesion of gastric cancer cells was significantly decreased after PA treatment. Compared with the control group, the wound healing area of the gastric cancer cells treated with different concentrations of PA decreased. The Transwell assay showed that the number of gastric cancer cells passing through the cell membrane were significantly reduced after PA treatment. In addition, after PA treatment, the cells’ movement distance and average movement speed were significantly lower than those of the control group. Finally, PA can significantly alter the expression of EMT-related proteins E-cadherin, N-cadherin, and Vimentin and decreased the expressions of metastasis-related proteins matrix metalloproteinase (MMP) 2, MMP-9 and tissue inhibition of matrix metalloproteinase (TIMP)1 in the gastric cancer cells. Conclusions: Triterpenoids from P. cocos have significant biological activity against gastric cancer, and the mechanism may be involved in the process of epithelial–mesenchymal transformation.

Laminin 511-E8 Fragment Offers Superior Adhesion Properties for Gastric Cancer Cells Compared with Full-Length Laminin 511.

Simple SummaryNumerous studies over the past few decades have revealed that the interactions of gastric cancer cells with laminins through integrins play important roles in tumor cell proliferation, infiltration, and metastasis. However, the association between gastric cancer cells and the laminin E8 fragment, which is the smallest integrin-binding component, has not been investigated. In this study, we revealed that the laminin 511-E8 fragment had a greater impact on the adhesion, morphology, and proliferation of gastric cancer cells than full-length laminin 511. Thus, the laminin 511-E8 fragment is considered to be suitable for investigating the interaction between gastric cancer cells and extracellular matrices in tumor invasion and metastasis. Further, the involvement of Cdc42 in the laminin 511-E8 fragment-induced enhanced adhesion of gastric cancer cells was suggested.Background: The interaction between cancer cells and laminin (Ln) is a key event in tumor invasion and metastasis. Previously, we determined the effect of full-length Ln511 on gastric cancer cells. However, the interactions between the Ln511-E8 fragment, a truncated protein of Ln511, and gastric cancer cells have not been investigated. Methods: We investigated the adhesion properties of gastric cancer cells to full-length Ln511 and Ln511-E8 fragments. Results: The proliferation of four gastric cancer cell lines (SH-10-TC, MKN74, SC-6-JCK, and MKN45) was highest on the Ln511-E8 fragment. Further, a larger cytoplasm was observed in SH-10-TC and MKN74 cells cultured on full-length Ln511 or Ln511-E8 fragments. The percentage of adhesive cells was highest on the Ln511-E8 fragment in all four cell lines. Moreover, adhesion of the gastric cancer cells to Ln511-E8 fragment-coated plates was reduced by the Cdc42 GTPase inhibitor in a dose-dependent manner, suggesting the involvement of Cdc42 in the Ln511-E8 fragment-induced enhanced adhesion of gastric cancer cells. Conclusions: The Ln511-E8 fragment had a greater impact on the adhesion, morphology, and proliferation of gastric cancer cells than full-length laminin. Thus, the Ln511-E8 fragment is suitable for investigating the interaction between gastric cancer cells and extracellular matrices in tumor invasion and metastasis.

Removal of small extracellular vesicles inhibits the progression of peritoneal dissemination in gastric cancer.

The prognosis of gastric cancer patients with peritoneal dissemination is extremely poor and effective treatment for peritoneal dissemination has not been established. Gastric cancer-derived small extracellular vesicles play an important role in the development of a favorable microenvironment for peritoneal metastasis and progression of peritoneal dissemination. Here, we aimed to investigate the transformation of gastric cancer cells by removing gastric cancer-derived small extracellular vesicles and to develop a novel therapy for inhibiting peritoneal dissemination. Gastric cancer cells were cultured in medium containing gastric cancer- and peritoneal mesothelium-derived small extracellular vesicles and in medium from which small extracellular vesicles were removed by ultracentrifugation. Cell function assays were performed in vitro, and the alternations in gene expression in gastric cancer cells were analyzed. The inhibitory effect of intraperitoneal lavage on peritoneal dissemination was investigated in vivo as a method to remove gastric cancer-derived small extracellular vesicles. Removal of gastric cancer-derived small extracellular vesicles suppressed the proliferative and migrative abilities of gastric cancer cells and the adhesion of gastric cancer cells to peritoneal mesothelial cells. It altered the expression of several genes related to the cell cycle and epithelial-mesenchymal transition pathways of gastric cancer cells, leading to the inhibition of gastric cancer cell growth and peritoneal dissemination in vivo. Our study provides novel insights into a novel therapy for inhibiting the peritoneal dissemination of gastric cancer by targeting gastric cancer-derived small extracellular vesicles to improve the prognosis of gastric cancer patients with peritoneal metastasis.

Inhibition of LPS-mediated TLR4 activation abrogates gastric adenocarcinoma-associated peritoneal metastasis.

Surgical resection, the cornerstone of curative intent treatment for gastric adenocarcinoma, is associated with a high rate of infection-related post-operative complications, leading to an increased incidence of metastasis to the peritoneum. However, the mechanisms underlying this process are poorly understood. Lipopolysaccharide (LPS), an antigen from Gram-negative bacteria, represents a potential mechanismvia induction of local and systemic inflammation through activation of Toll-like receptor (TLR).Here, we use both a novel ex vivo model of peritoneal metastasis and in vivo animal models to assess gastric cancer celladhesion to peritoneum both before and after inhibition of the TLR4 pathway.We demonstrate that activation of TLR4 by either LPS or Gram-negative bacteria (E. coli) significantly increases the adherence of gastric cancer cells to human peritoneal mesothelial cells, and that this increased adherence is abrogated by inhibition of the TLR4 signal cascade and downstream TAK1 and MEK1/2 pathways. We alsodemonstrate that the influence of LPS on adherence extends to peritoneal tissue and metastatic spread. Furthermore, we show that loss of TLR4 at the site of metastasis reduces tumor cell adhesion, implicating the TLR4 signaling cascade in potentiating metastatic adhesion and peritoneal spread.These results identify potential therapeutic targets for the clinical management of patients undergoing resection for gastric cancer.

MicroRNA-665 regulates the proliferation, apoptosis and adhesion of gastric cancer cells by binding to cadherin 3.

Numerous studies have reported that abnormal cadherin 3 (CDH3) and microRNA (miRNA/miR)-665 expression can induce the progression of gastric cancer (GC). However, the mechanism of interaction between miR-665 and CDH3 in GC requires further investigation. The present study aimed to investigate the influence of miR-665 and CDH3 in GC development. The effect of miR-665 and CDH3 on GC tissues and cell lines was examined using reverse transcription-quantitative PCR. Subsequently, CDH3 protein expression in GC cell lines was detected using western blotting. To confirm the association between miR-665 and CDH3, a dual-luciferase reporter assay system was employed. Cell proliferation and adhesion were analyzed using BrdU ELISA, MTT and cell adhesion assays. Finally, caspase-3 activity assay kit and FITC apoptosis detection kit were used for the determination of apoptosis of GC cells. The current findings confirmed the upregulation of CDH3 expression in GC cell lines and tissues. Experimental results indicated that CDH3 overexpression increased cell proliferation and adhesion, but decreased the apoptosis level of the cells. Similarly, the miR-665 inhibitor enhanced cell proliferation and adhesion, but inhibited apoptosis of GC cells. Additionally, it was observed that CDH3 was a direct target of miR-665 in GC cells and that miR-665 inhibited CDH3 expression, thereby repressing the progression of GC. In conclusion, the present study suggested that by targeting CDH3, miR-665 suppressed the progression of GC. These findings may provide a significant theoretical basis for future GC clinical therapy.

By modulating α2β1 integrin signalling, gastrin increases adhesion oF AGS-GR gastric cancer cells

Peritoneal metastasis is a major cause of recurrence of gastric cancer and integrins are key molecules involved in gastric cancer cells attachment to the peritoneum. The peptide hormone, gastrin, initially identified for its role in gastric acid secretion is also a growth factor for gastric mucosa. Gastrin has also been shown to contribute to gastric cancers progression. Here, we provide the first evidence that gastrin increases the adhesion of gastric cancer cells. Gastrin treatment induces the expression of α2 integrin subunit through a mechanism that involves the ERK pathway. We also observed in response to gastrin an increase in the amount of α2 integrin associated with β1subunit. In addition, gastrin-stimulated cell adhesion was blocked with an anti-α2β1 integrin neutralizing antibody. We also show that gastrin activates the integrin pathway via the phosphorylation of β1 integrin by a Src family kinase. This mechanism may contribute to the enhancement of cell adhesion observed in response to gastrin since we found an inhibition of gastrin-mediated cell adhesion when cells were treated with a Src inhibitor. By regulating one of the key step of the metastatic process gastrin might contribute to increase the aggressive behaviour of human gastric tumours.

REG3A promotes the proliferation, migration, and invasion of gastric cancer cells.

The mechanism underlying the metastasis of gastric cancer (GC) cells remains elusive. REG3A is considered an oncogene in various cancers, but in GC its role is unclear. Here, we report that the expression of REG3A was significantly increased in the tumor tissues of patients with GC compared with the matched normal tissues. Knockdown of REG3A induced by specific small interfering RNA (siRNA) significantly repressed the proliferation of GC cells for 24 h or 48 h. Moreover, knockdown of REG3A significantly suppressed the migration, invasion, and adhesion of GC cells in vitro. Furthermore, knockdown of REG3A reduced the phosphorylation of JAK2 and STAT3, and altered the messenger RNA (mRNA) and protein expression levels of E-cadherin, Snail, RhoC, MTA1, MMP-2, and MMP-9. Taken together, REG3A is overexpressed in GC and promotes the proliferation, migration, invasion, and adhesion of GC cells by regulating the JAK2/STAT3 signal pathway. REG3A may be a potential therapeutic target for GC.

CXCL1 from tumor-associated lymphatic endothelial cells drives gastric cancer cell into lymphatic system via activating integrin β1/FAK/AKT signaling

Crosstalk between lymphatic endothelial cells (LECs) and tumor cells in the tumor microenvironment plays a crucial role in tumor metastasis. Our previous study indicated chemokine (C-X-C motif) ligand 1 (CXCL1) from LECs stimulates the metastasis of gastric cancer. However, the mechanism is still unclear. Here, we successfully isolated tumor-associated LECs (T-LECs) and normal LECs (N-LECs) from clinical samples by magnetic-activated cell sorting system (MACS) and proved that CXCL1 expression was elevated in T-LECs compared with N-LECs in situ and vitro. Besides, we demonstrated that CXCL1 secreted by T-LECs promoted the migration, invasion, and adhesion of gastric cancer cells by upregulating integrin β1, MMP2, and MMP9. Furthermore, CXCL1 induced MMP2/9 expression by activating integrin β1-FAK-AKT signaling. In the animal model, CXCL1 overexpressed in LECs increased the lymph node metastasis of gastric cancer. In conclusion, CXCL1 expression in T-LECs was upregulated, and CXCL1 secreted by T-LECs promoted the lymph node metastasis of gastric cancer through integrin β1/FAK/AKT signaling, leading to MMP2 and MMP9 expression. Therefore, CXCL1 produced in T-LECs represents a potentially promising target for treating gastric cancer.

High extracellular pressure promotes gastric cancer cell adhesion, invasion, migration and suppresses gastric cancer cell differentiation.

Slightly increased pressure stimulates tumor cell adhesion and proliferation. In the present study, we aimed to evaluate the effects of high pressure on gene expression and the biological behavior of gastric cancer cells. After incubation for 30min at 37˚C under ambient and increased pressure, one portion of SGC7901 cells was used for cell proliferation and apoptosis assays, cell cycle analysis, adhesion invasion or migration assays. The other portion of cells was harvested for detection of matrix metalloproteinase-2 (MMP-2), inhibitor of DNA binding-1 (ID1), sonic Hedgehog (SHH) and E-cadherin expression by western blotting or RT-PCR. In addition, we investigated the effects of high pressure on SGC7901 cell ultrastructure by transmission electron microscopy. We found that the adhesion fold under increased pressure of 760 and 1,520mmHg was 2.39±1.05 (P<0.05) and 2.47±0.85 (P<0.01) as compared with the control, respectively. The invasion fold was 3.42±2.06 (P<0.05) and 5.13±2.49 (P<0.01) as compared with the control, respectively. The migration was 1.65±0.20 (P<0.001) and 2.53±0.50 (P<0.001) as compared with the control, respectively. At increased pressure, MMP-2 and ID1 expression increased significantly, while the expression of SHH decreased significantly. However, we did not find significant change in proliferation, apoptosis, cell cycle or ultrastructure of the SGC7901 cells under high pressure. In conclusion, high pressure promoted the adhesion, invasion and migration of SGC7901 cells. Moreover, the present study suggests that the pressure-augmented invasion and migration may be related to the increase in MMP-2 expression. Moreover, high pressure may suppress SGC7901 cell differentiation, which may result from the change in SHH and ID1 expression.

Abstract A29: Gram-negative bacterial infection enhances the potential of gastric adenocarcinoma peritoneal metastasis via TNFR1 dependent manner

Abstract Adenocarcinoma of the proximal stomach is the fastest rising malignancy in North America, and is associated with a high rate of recurrence to the peritoneum. As part of cancer treatment, the majority of patients undergo at least one invasive surgical procedure. Recent clinical data has linked postoperative infection complications with adverse oncologic outcomes; however, the underlying mechanisms are unclear. Emerging evidence suggests that the release of TNFa, a key inflammatory cytokine during infection facilitates cancer progression. The role and mechanisms the gram-negative bacterial infections play in facilitating the metastatic potential of gastric cancer to the peritoneum is entirely unknown. We hypothesized that incubation of gastric cancer cells and MC with heat-inactivated E. Coli or LPS can augment gastric cancer cell adhesion and invasion via TNFR1 signaling and increase the potential of peritoneal metastasis. Incubation of human gastric cancer cells or/and MC with heat inactivated E. coli, LPS or TNFa significantly increased in vitro adhesion 3-4 folds to MC and enhanced in vitro invasion. These enhanced cell adhesion and invasion phenotypes following incubation with LPS or E. coli were attenuated at three levels: inhibition of TLR4 (Eritoran), inhibition of TNFR1 (anti-TNFR1/isotype control antibodies) or p38 MAPK inhibitor (BIRB0796). TNFa treatment also increases CD54, CD44 and CD29 expression on cancer cells and MC. To further validate in vitro results, a novel ex-vivo murine peritoneal metastasis model is developed. We report that ex vivo gastric cancer cells adhesion to murine peritoneum is augmented by overnight LPS, E. Coli and TNFa treatments and this effect was abrogated when TNFR1-/- mouse peritoneum is used or in the presence of TNFR1 monoclonal or isotype control antibodies. These findings implicate TNFa in the process of gastric cancer metastasis to peritoneum in the context of systemic infection and identify TNFa as potential therapeutic targets. Citation Format: Malak Alzahrani, Betty Giannias, France Bourdeau, Rafael Kayano, Lorenzo Ferri. Gram-negative bacterial infection enhances the potential of gastric adenocarcinoma peritoneal metastasis via TNFR1 dependent manner. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Metastasis; 2015 Nov 30-Dec 3; Austin, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(7 Suppl):Abstract nr A29.

Endoglin overexpression mediates gastric cancer peritoneal dissemination by inducing mesothelial cell senescence

Peritoneal dissemination (PD), which is highly frequent in gastric cancer (GC) patients, is the main cause of death in advanced GC. Senescence of human peritoneal mesothelial cells (HPMC) may contribute to GC peritoneal dissemination (GCPD). In this study of 126 patients, we investigated the association between Endoglin expression in GC peritoneum and the clinicopathological features. The prognosis of patients was evaluated according to Endoglin and ID1 expression. In vitro, GC cell (GCC)-HPMC coculture was established. Endoglin and ID1 expression was evaluated by Western blot. Cell cycle and HPMC senescence were analyzed after harvesting HPMC from the coculture. GCC adhesion and invasion to HPMC were also assayed. Our results showed that positive staining of Endoglin (38%) was associated with a higher TNM stage and higher incidence of GCPD (both P < .05). Kaplan-Meier analysis showed that the patients who were Endoglin positive had a shorter survival time compared with Endoglin-negative patients (P = .02). Using the HPMC and GCC adherence and invasion assay, we demonstrated that transforming growth factor beta 1 (TGF-β)1-induced HPMC senescence was attenuated by silencing the Endoglin expression, which also prevented GCC attachment and invasion. Our study indicated a positive correlation between Endoglin overexpression and GCPD. Up-regulated Endoglin expression induced HPMC senescence via TGF-β1 pathway. The findings suggest that Endoglin-induced HPMC senescence may contribute to peritoneal dissemination of GCCs.

Knockdown of Radixin Suppresses Gastric Cancer Metastasis In Vitro by Up-Regulation of E-Cadherin via NF-κB/Snail Pathway

Background/Aims: Radixin has recently been shown to correlate with the metastasis of gastric cancer, but the pathogenesis is elusive. Adhesion proteins contribute to the regulation of metastasis, and thus this study sought to investigate the role of radixin in the migration, invasion and adhesion of gastric cancer cells, as well as its interaction with adhesion proteins in vitro. Methods: Radixin stable knockdown human gastric carcinoma SGC-7901 cells were constructed. Alterations in the migration, invasion and adhesion ability were examined by matrigel-coated plate and transwell assays. The expression pattern of adhesion proteins, including E-cadherin, β-catenin and claudin-1, was determined by quantitative real-time PCR and western blot. Possible involvement of NF-κB/snail pathway was also evaluated. Results: Stable knockdown of radixin significantly suppressed migration and invasion, but enhanced adhesion in SGC-7901 cells. The expression of E-cadherin was manifestly increased in radixin knockdown cells, whereas the expression of β-catenin and claudin-1 was unchanged. The nuclear exclusion of NF-κB followed by conspicuous reduction of snail expression was involved in the regulation of E-cadherin expression. Conclusions: Radixin knockdown suppresses the metastasis of SGC-7901 cells in vitro by up-regulation of E-cadherin. The NF-κB/snail pathway contributes to the regulation of E-cadherin in response to depletion of radixin.

Dehydroeffusol effectively inhibits human gastric cancer cell-mediated vasculogenic mimicry with low toxicity

Accumulated data has shown that various vasculogenic tumor cells, including gastric cancer cells, are able to directly form tumor blood vessels via vasculogenic mimicry, supplying oxygen and nutrients to tumors, and facilitating progression and metastasis of malignant tumors. Therefore, tumor vasculogenic mimicry is a rational target for developing novel anticancer therapeutics. However, effective antitumor vasculogenic mimicry-targeting drugs are not clinically available. In this study, we purified 2,7-dihydroxyl-1-methyl-5-vinyl-phenanthrene, termed dehydroeffusol, from the traditional Chinese medicinal herb Juncus effusus L., and found that dehydroeffusol effectively inhibited gastric cancer cell-mediated vasculogenic mimicry in vitro and in vivo with very low toxicity. Dehydroeffusol significantly suppressed gastric cancer cell adhesion, migration, and invasion. Molecular mechanistic studies revealed that dehydroeffusol markedly inhibited the expression of a vasculogenic mimicry master gene VE-cadherin and reduced adherent protein exposure on the cell surface by inhibiting gene promoter activity. In addition, dehydroeffusol significantly decreased the expression of a key vasculogenic gene matrix metalloproteinase 2 (MMP2) in gastric cancer cells, and diminished MMP2 protease activity. Together, our results showed that dehydroeffusol effectively inhibited gastric cancer cell-mediated vasculogenic mimicry with very low toxicity, suggesting that dehydroeffusol is a potential drug candidate for anti-gastric cancer neovascularization and anti-gastric cancer therapy.

Role of transforming growth factor-β1 in epithelial-mesenchymal transition of mesothelial cells and its effect on peritoneal metastasis of gastric cancer

To elucidate the role of transforming growth factor-beta1(TGF-β1) in epithelial-mesenchymal transition of mesothelial cells and peritoneal metastasis of gastric cancer. HMrSV5 cells, a human peritoneal mesothelial cell line, were incubated with TGF-β1, and their morphological changes were observed by phase contrast microscopy. Expressions of α-smooth muscle actin (α-SMA), vimentin, cytokeratin, E-cadherin, phosphorylated-Smad2 and Smad2 were examined by Western blotting. After fibroblastic-like mesothelial cells were co-incubate with HSC-39 cells(gastric cancer cell line), the adhesion and invasion potential of HSC-39 were evaluated by adhesion and invasion assay in vitro. Few mesothelial cells converted to spindle fibroblast-like morphology for 24 h, and remarkable phenotypic changes were observed at 72 h of TGF-β1 activation. TGF-β1 could induce α-SMA and vimentin expression, and down-regulate cytokeratin and E-cadherin expression in mesothelial cells (P<0.05). TGF-β1 induced phosphorylation of Smad2 within 15 min of stimulation, reached a maximum at 30 min after treatment and remained high level during the experiment without affecting total Smad2 expression(P>0.05). The percentage of HSC-39 gastric cancer cells adhered were significantly increased as compared to the control. When the mesothelial cells were treated by TGF-β1 for 72 h, the increased adhesion percentage was(146±17)%(P<0.05). After fibroblastic-like mesothelial cells co-incubated with HSC-39 cells for 48 h, more cancer cells [(61.1±11.4) cells/view field] invaded the coated membrane as compared to the control group [(31.9±8.1) cells/view field] (P<0.05). TGF-β1 can induce the transition of mesothelial cells into myofibroblasts and Smad2 signal pathway may play a role in this transition, which is associated with increased adhesion and invasiveness of gastric cancer cells, and provides favorable environment for the dissemination of gastric cancer.