Angiogenesis In Gastric Cancer Research Articles

High expression of RELM-α correlates with poor prognosis and promotes angiogenesis in gastric cancer.

Accumulating evidence indicates that resistin-like molecule-α (RELM-α) is involved in angiogenesis, while the clinical significance and the exact role of RELM-α in gastric cancer remain obscure. The aim of the present study was to evaluate the clinical significance of RELM-α in gastric cancer, and to investigate its effective mechanisms in order to identify a potential therapeutic target. The expression levels of RELM-α in 92 gastric cancer and adjacent normal tissues were investigated and the relationship between RELM-α expression and the clinicopathological characteristics was explored. To investigate the potential role of RELM-α in gastric cancer cell biological behavior, the cell proliferation, migration and invasion assays were conducted using two gastric cancer cell lines (SGC7901 and MKN45). We also assessed whether RELM-α gene silencing modulates angiogenesis using small interference RNA in cancer cell lines, and investigated its effect on nuclear factor (NF)-κB activation and vascular endothelial growth factor (VEGF) and MMP-9 expression. Contrasting sharply with the strong RELM-α-positive tumors, adjacent normal tissues and cell lines exhibited negative or weakly positive expression (P<0.01). High expression level of RELM-α was associated with advanced stage and tumor size (P<0.01). The silencing of RELM-α expression by Ad5/F35-siRNA treatment significantly inhibited cell migratory and invasive ability in SGC7901 and MKN45 gastric cancer cells compared with the control and Ad5/F35 vector-transfected cell lines (P<0.01). However, the silencing of RELM-α expression also significantly blocked NF-κB activation and attenuated VEGF and MMP-9 expression. The data demonstrated that RELM-α is a promising novel biomarker of angiogenesis in patients with gastric cancer. The study identified that the silencing of RELM-α expression may regulate the proliferation, invasion and migration of gastric cancer cells by targeting VEGF/MMP-9, and the mechanism involved tissue angiogenesis via the NF-κB signaling pathway.

13 DARPP32: A Bridge Between Pro-Inflammatory Signaling and Angiogenesis in Gastric Cancer

13 DARPP32: A Bridge Between Pro-Inflammatory Signaling and Angiogenesis in Gastric Cancer

Sa1993a Reduced Expression of Prostaglandin Transporter Promotes Angiogenesis in Gastric Cancer

Background & Aims: Colorectal cancer (CRC) cells (unlike normal colonic epithelial cells) secrete VEGF, which drives these cells proliferation and promotes tumor-related angiogenesis. The mechanism(s) of increased, aberrant VEGF expression in CRC cells is not known, but is likely related to transcriptional activation of VEGF gene.We hypothesized that: 1) upregulated importin-α in CRC cells (which facilitates nuclear transport of transcription factors: HIF1α and CREB, and is essential for VEGF gene promoter activation) is the underlying mechanism for increased VEGF expression in these cells and CRC cell proliferation, and, 2) inhibition and/or silencing of importin-α in CRC cells will inhibit VEGF gene activation and CRC cell proliferation. Ivermectin is a specific inhibitor of importin α nuclear transport (Biochem J. 2012: 1;443(3):851-6). We examined whether treatment of CRC cell lines with ivermectin could inhibit CRC cell growth. Methods: We used: (a) human CRC cell lines HCT116 & HT29 and (b) normal colonic epithelial cells NCM356 & NCM460. We treated cultured CRC cells with ivermectin (50 μM, 6 hr; specific inhibitor of importin-α nuclear transport), with importin α specific siRNA or control RNA (100nM, 48 hr). Add-back studies included treatment with exogenous VEGF (20ng/ml). Studies: 1) mRNA and protein expression of importin-α and VEGF by Real-Time RT-PCR, and/or Western blotting and immunostaining, respectively; 2) VEGF secretion into culture medium by ELISA; 3) translocation of importin to the nucleus in CRC vs. normal cells; and 4) cell proliferation by BrdU assay. Results: 1) CRC cell lines express high levels of VEGF and secrete large amounts of VEGF (up to 1530 pg/ml) into culture medium at 24 hours vs. normal epithelial cells, which only secrete minimal VEGF ( 40% (p< 0.05); 3) Selective inhibition of importin-α in CRC cells using ivermectin significantly reduced VEGF expression by ~3-fold (p<0.01) and proliferation of these cells by 2.4-fold (p<0.01). Treatment with exogenous VEGF partly reversed inhibited by ivermectin cell proliferation; 4) Importin-α silencing in CRC cells significantly reduced VEGF expression and proliferation of these cells by 2.2-fold and 2fold (both p<0.01), respectively; treatment with exogenous VEGF following importin-α silencing reversed inhibition of cell proliferation by 2-fold (p < 0.01). Conclusions: 1) VEGF gene activation in CRC cells requires functional importin-α; 2) importin-α mediates increased proliferation of CRC cells; downregulation of importin-α with specific siRNA or its inhibition with specific inhibitor ivermectin inhibits CRC cell proliferation; 3) These studies suggest a potential therapeutic role of ivermectin in inhibiting CRC cell proliferation.

Melatonin Inhibit the Angiogenesis of Gastric Cancer by Nuclear Receptor

This study aims to explore the relationship between melatonin (MLT) and gastric cancer angiogenesis by nuclear receptor with ELISA, real‐time quantitative RT‐PCR, IHC, Western blot, and siRNA methods.1. The anti‐angiogenic function of MLT on the human gastric cancer cells and the impact on MLT nuclear receptor in vitro. MLT was time‐dependent in inhibiting proliferation of human gastric cancer cell lines MGC‐803, SGC‐7901, and AGS; Chemical hypoxia simulated by 100uM CoCl2 increased proliferation of SGC‐7901 cells; MLT decreased the expression of VEGF mRNA and protein of SGC‐7901; MLT decreased the expression of nuclear receptor RZR/RORγ mRNA and protein of SGC‐7901.2. The anti‐angiogenic mechanism of MLT on human gastric cancer cells SGC‐7901 in vitro and the targets of MLT nuclear receptor RZR/RORγ. The RZR/RORγ silent by siRNA antagonized significantly MLT's inhibition on gastric cancer cell proliferation.After the 24h intervention by 3mM MLT, the mRNA and protein expression of RZR / RORγ,SENP1,HIF‐1α and VEGF was significantly decreased; but the expression of SENP1, HIF‐1α, VEGF mRNA and protein was increased.3. The anti‐angiogenic mechanism of MLT on the gastric cancer in vivo with nude mice.We established the tumor‐bearing nude mice model of gastric cancer SGC‐7901 with intervention by different concentrations of MLT. MLT reduced the tumor volume and weight of the gastric cancer; MLT inhibited tumor proliferation and angiogenesis by decreasing the expression of RZR / RORγ ,SENP1 ,HIF‐1α, VEGF and MVD.The present study confirmed that MLT is able to inhibit gastric cancer angiogenesis both in vivo and in vitro. It's major mechanism is reducing the expression of nuclear receptor RZR/RORγ and decreasing the expression of SENP1,HIF‐ 1α,VEGF.

Forkhead Transcription Factor FOXO1 Inhibits Angiogenesis in Gastric Cancer in Relation to SIRT1.

PurposeWe previously reported that forkhead transcription factors of the O class 1 (FOXO1) expression in gastric cancer (GC) was associated with angiogenesis-related molecules. However, there is little experimental evidence for the direct role of FOXO1 in GC. In the present study, we investigated the effect of FOXO1 on the tumorigenesis and angiogenesis in GC and its relationship with SIRT1.Materials and MethodsStable GC cell lines (SNU-638 and SNU-601) infected with a lentivirus containing FOXO1 shRNA were established for animal studies as well as cell culture experiments. We used xenograft tumors in nude mice to evaluate the effect of FOXO1 silencing on tumor growth and angiogenesis. In addition, we examined the association between FOXO1 and SIRT1 by immunohistochemical tissue array analysis of 471 human GC specimens and Western blot analysis of xenografted tumor tissues.ResultsIn cell culture, FOXO1 silencing enhanced hypoxia inducible factor-1α (HIF-1α) expression and GC cell growth under hypoxic conditions, but not under normoxic conditions. The xenograft study showed that FOXO1 downregulation enhanced tumor growth, microvessel areas, HIF-1α activation and vascular endothelial growth factor (VEGF) expression. In addition, inactivated FOXO1 expression was associated with SIRT1 expression in human GC tissues and xenograft tumor tissues.ConclusionOur results indicate that FOXO1 inhibits GC growth and angiogenesis under hypoxic conditions via inactivation of the HIF-1α–VEGF pathway, possibly in association with SIRT1. Thus, development of treatment modalities aiming at this pathway might be useful for treating GC.

CEACAM6 promotes tumor angiogenesis and vasculogenic mimicry in gastric cancer via FAK signaling

CEACAM6 is a member of glycosylphosphatidylinositol-linked immunoglobulin superfamily that is implicated in a variety of human cancers. In our previous study, we reported that CEACAM6 was overexpressed in gastric cancer tissues and promoted cancer metastasis. The purpose of this study is to determine the role of CEACAM6 in tumor angiogenesis and mimicry formation. We found that overexpressed CEACAM6 promoted tubule formation dependent on HUVEC cells and vasculogenic mimicry formation of gastric cancer cells; opposing results were achieved in CEACAM6-silenced groups. Moreover, we found that mosaic vessels formed by HUVEC cells and gastric cancer cells were observed in vitro by 3D-culture assay. Overexpressed CEACAM6 in gastric cancer cells promoted tumor growth, VEGF expression and vasculogenic mimicry structures formation in vivo. In accordance with these observations, we found that phosphorylation of FAK and phosphorylation of paxillin were up-regulated in CEACAM6-overexpressing gastric cancer cells, and FAK inhibitor Y15 could reduce tubule and vasculogenic mimicry formation. These findings suggest that CEACAM6 promotes tumor angiogenesis and vasculogenic mimicry formation via FAK signaling in gastric cancer and CEACAM6 may be a new target for cancer anti-vascular treatment.

Reduced miR-126 expression facilitates angiogenesis of gastric cancer through its regulation on VEGF-A

miR-126 is an endothelial-specific microRNA essential for governing vascular integrity and angiogenesis. Its role in tumor angiogenesis of gastric cancer (GC) is unclear. This study aimed at determining the role of miR-126 in GC angiogenesis. Down-regulation of miR-126 was found to inversely correlate with an increased microvessel density (MVD) and vascular endothelial growth factor A (VEGF-A) expression in gastric cancer tissues. Bioinformatics analysis and luciferase reporter assay revealed that miR-126 directly targeted the 3'-untranslated region (3'-UTR) of VEGF-A mRNA. In addition, the restoration of miR-126 expression by lentivirus-miR-126 (Lenti-miR-126) transfection obviously reduced the expression of VEGF-A and the activition of its downstream genes, Akt, mTOR and Erk1/2 in gastric cancer cell lines SGC-7901, MKN-28 and MKN-45. In contrast, the down-regulation of miR-126 expression by lentivirus-anti-miR-126 (Lenti-anti-miR-126) transfection obviously up-regulated the expression of VEGF-A and its downstream signaling pathways. In vivo xenograft mice model experiments clarified the down-regulation of VEGF-A and MVD as well as inhibition of tumor growth by up-regulation of miR-126. Overall, the results from our study suggested that miR-126 could suppress tumor growth and tumor angiogenesis of GC through VEGF-A signaling, and it is a novel potential therapeutic target for GC.

Ramucirumab: successfully targeting angiogenesis in gastric cancer.

Gastric cancer is the fourth most common cancer globally and represents the second most common cause of cancer-related mortality. Early detection, aggressive surgical resection, and postoperative adjuvant therapy have led to survival improvement for early-stage gastric cancer, particularly in Asian countries. Unfortunately, advanced gastric cancer continues to pose a formidable challenge with few gains being reported recently. Trastuzumab was the first targeted agent to be approved for the treatment of advanced gastric cancer in 2010. The failure of the AVAGAST trial was a setback for antiangiogenic therapy for this disease. Ramucirumab is a monoclonal antibody that binds to VEGF-R2 and prevents its activation. The recent REGARD trial was a randomized phase III trial of ramucirumab vs. placebo for patients with advanced, pretreated gastric cancer that met its primary endpoint of increased overall survival. The toxicity of ramucirumab was modest in this setting, with an increased risk of grade 3 or higher hypertension (8% vs. 3%, with ramucirumab and placebo, respectively). The subsequent RAINBOW trial of paclitaxel plus ramucirumab vs. paclitaxel plus placebo for advanced pretreated gastric cancer confirmed the survival advantage of this antiangiogenic agent in gastric cancer. Ramucirumab is the first FDA-approved therapy for advanced gastric cancer after prior chemotherapy.

Reduced miR-126 expression facilitates angiogenesis of gastric cancer through its regulation on VEGF-A.

miR-126 is an endothelial-specific microRNA essential for governing vascular integrity and angiogenesis. Its role in tumor angiogenesis of gastric cancer (GC) is unclear. This study aimed at determining the role of miR-126 in GC angiogenesis. Down-regulation of miR-126 was found to inversely correlate with an increased microvessel density (MVD) and vascular endothelial growth factor A (VEGF-A) expression in gastric cancer tissues. Bioinformatics analysis and luciferase reporter assay revealed that miR-126 directly targeted the 3'-untranslated region (3'-UTR) of VEGF-A mRNA. In addition, the restoration of miR-126 expression by lentivirus-miR-126 (Lenti-miR-126) transfection obviously reduced the expression of VEGF-A and the activition of its downstream genes, Akt, mTOR and Erk1/2 in gastric cancer cell lines SGC-7901, MKN-28 and MKN-45. In contrast, the down-regulation of miR-126 expression by lentivirus-anti-miR-126 (Lenti-anti-miR-126) transfection obviously up-regulated the expression of VEGF-A and its downstream signaling pathways. In vivo xenograft mice model experiments clarified the down-regulation of VEGF-A and MVD as well as inhibition of tumor growth by up-regulation of miR-126. Overall, the results from our study suggested that miR-126 could suppress tumor growth and tumor angiogenesis of GC through VEGF-A signaling, and it is a novel potential therapeutic target for GC.

The effect of tumor susceptibility gene 101 on the angiogenesis of gastric cancer cells

Objective To investigate the effect of tumor susceptibility gene 101 (TSG101) on angiogenesis of gastric cancer SGC7901 cells.Methods Cells were divided into the non-transfection group,the empty plasmid transfection group and TSG101 eukaryotic expression plasmid transfection group (the TSG101 transfection group).Then we examined the relationship between TSG101 expression and tumor angiogenesis in vivo and in vitro experiment respectively.To detect the expression of vascular endothelial growth factor (VEGF),vascular endothelial growth factor receptor (VEGFR) and the angiogenesis.Resuits (1) It was showed that the angiogenesis number of HUVEC and the expression levels of VEGF in the TSG101 transfection group was significantly higher than that of the empty plasmid transfection group and the non-transfection group in vitro experiment (19.50 ± 3.02 vs.11.50 ± 2.51,11.34 ± 1.63 and 514.80 ± 18.16 vs.306.58 ± 20.86,305.69 ± 29.93,all P ＜ 0.05).(2) It was showed the microvascular density in tumor tissue of nude mice and the serum VEGF concentration of the TSG101 transfection group was significantly higher than that of the empty plasmid transfection group and the non-transfection group in vivo experiment [11.16±2.31 vs.5.33 ±1.63,4.66 ±1.36 and (340.64±19.15) ng/L vs.(219.34 ± 13.56),(206.10 ± 25.85) ng/L,all P ＜ 0.05].The expressions of VEGF and VEGFR of the TSG101 transfection grou p (0.548 ± 0.032,0.345 ± 0.042) of tumor tissue in nude mice were significantly higher than that of the non-transfection group (0.350 ± 0.034,0.203 ± 0.030) and the empty plasmid transfection group (0.327 ± 0.020,0.206 ± 0.036,P ＜ 0.05).Conclusion The high-expression of TSG101 in SGC7901 cells may promote angiogenesis of gastric cancer by up-regulated expression of VEGF. Key words: Tumor susceptibility gene 101 ; Angiogenesis; Vascular endothelial growth factor; Gastric cancer

Thymidine phosphorylase activates NFκB and stimulates the expression of angiogenic and metastatic factors in human cancer cells

Thymidine phosphorylase (TP) promotes angiogenesis and metastasis, and confers resistance to anticancer agents in some cancer cell types. We previously reported that TP stimulates the expression of interleukin (IL)-8 in human KB cancer cells by an unknown mechanism. A mutation in the nuclear factor (NF)κB binding site of the IL-8 promoter suppressed promoter activity in KB/TP cells that overexpress TP. Specifically inhibiting NFκB by using BY11-7082 also suppressed TP-induced IL-8 promoter activity and IL-8 expression. Moreover, TP overexpression led to the activation of NFκB and an upregulation in the expression of its target genes, and increased phosphorylated IKKα/β protein levels, while promoting IκBα degradation as well as p65 phosphorylation and nuclear localization. The activation of NFκB in KB/TP cells was suppressed by the antioxidants N-acetylcysteine and EUK-8. In addition, in gastric cancer tissue samples, the expression of the NFκB-regulated genes, including IL-8, IL-6, and fibronectin-1 was positively correlated with TP expression. These findings indicate that reactive oxygen species mediated NFκB activation by TP increases the expression of genes that promote angiogenesis and metastasis in gastric cancer.

PP242 suppresses cell proliferation, metastasis, and angiogenesis of gastric cancer through inhibition of the PI3K/AKT/mTOR pathway.

Although preclinical work with rapalogs suggests potential in the treatment of gastric cancer, they have been less successful clinically. In this study, we report the impact of the investigational drug PP242, a potent and selective small-molecule active-site TORC1/2 kinase inhibitor, on tumor growth and metastasis. The antiproliferative effect of PP242 was assessed using the Cell Counting Kit-8 assay. The migration and invasion potential were analyzed using wound-healing and transwell assays, respectively. The Matrigel capillary tube formation assay was performed to mimic in-vivo angiogenesis. Immunoblotting and immunofluorescence were used to observe protein levels and distribution of actin fibers. Finally, p-mammalian target of rapamycin (mTOR) expression was detected on gastric cancer tissues using immunohistochemistry. First, PP242 potently inhibited cell proliferation in gastric cancer cell lines and in human endothelial cells in vitro at the IC50 ranged from 50 to 500 nmol/l. Then, an inhibitory effect of PP242 on metastasis was observed in gastric cancer cell AGS, along with the cytoskeletal rearrangements and suppression of the phosphorylation of PI3K downstream factors including AKT, mTOR, and P70S6K. Furthermore, PP242 was found to decrease the tube formation and migration of human umbilical vein endothelial cells. Using immunohistochemistry, we found that p-mTOR staining was observed in 41.8% (82/196) of gastric cancer tissues and correlated with depth of mural invasion, lymph node metastasis, tumor node metastasis stage, and vascular invasion. These results show that PP242 suppresses cell proliferation and angiogenesis of gastric cancer through inhibition of the PI3K/AKT/mTOR pathway, which might be an effective novel therapeutic candidate against gastric cancer in the future.

Anti-angiogenic therapies for advanced esophago-gastric cancer.

Neo-vascularization is a vital process for tumor growth and development which involves the interaction between tumor cells and stromal endothelial cells through several growth factors and membranous receptors which ultimately activate pro-angiogenic intracellular signaling pathways. Inhibition of angiogenesis has become a standard treatment option for several tumor types including colorectal cancer, glioblastoma and ovarian cancer. In gastric cancer, the therapeutic role of anti-angiogenic agents is more controversial. Bevacizumab and ramucirumab, two monoclonal antibodies, which target vascular endothelial growth factor-A and vascular endothelial growth factor receptor-2, respectively, have been demonstrated antitumor activity in patients with tumors of the stomach or esophagogastric junction. However, especially for bevacizumab, this antitumor activity has not consistently translated into a survival advantage over standard treatment in randomized trials. In this article, we provide an overview of the role of angiogenesis in gastric cancer and discuss the results of clinical trials that investigated safety and effectiveness of antiangiogenic therapies in this disease. A review of the literature has been done using PubMed, ClinicalTrials.gov website and the ASCO Annual Meeting Library.

Helicobacter pylori promotes VEGF expression via the p38 MAPK‑mediated COX‑2‑PGE2 pathway in MKN45 cells.

Helicobacter pylori has been suggested to be the major cause of gastric malignancy. However, the pathogenesis and molecular mechanisms of gastric tumorigenesis induced by H. pylori infection are yet to be elucidated. In the present study, the expression levels of vascular endothelial growth factor (VEGF), which has been suggested to promote angiogenesis in gastric cancer, were found to be elevated in H. pylori-infected MKN45 cells. Furthermore, it was demonstrated that the expression of VEGF was modulated by the p38 mitogen-activated protein kinases (MAPK) pathway via regulation of the cyclooxygenase (COX)-2 pathway. It was also found that prostaglandin E2 (PGE2) and its receptor EP2/EP4 may mediate the upregulation of VEGF in gastric cells exposed to H. pylori. In combination, these results suggest that VEGF expression is regulated by the p38 MAPK COX‑2-PGE2-EP2/EP4 pathway in gastric cancer cells induced by H. pylori. This provides a theoretical basis for the investigation of the pathogenesis of H. pylori‑induced gastric cancer.

Expression of carcinoembryonic antigen-related cell adhesion molecule 1(CEACAM1) and its correlation with angiogenesis in gastric cancer

ObjectiveTo examine the expression of carcinoembryonic antigen-related cell adhesion molecule 1(CEACAM1) and CD34 in gastric adenocarcinoma, and to investigate their relations with clinical pathology-related factors. MethodsImmunohistochemistry (IHC) was used to analyze the expression of CEACAM1 and CD34, and micro-vessel density (MVD) marked by CD34 was calculated in 208 cases of human gastric adenocarcinoma and in 56 cases of normal human gastric tissues. ResultsThere was no expression of CEACAM1 in normal gastric mucosa. However, all of the gastric adenocarcinoma tissues expressed CEACAM1 with cytoplasmic and/or membranous staining. CEACAM1 expression was classified as high and low (137/208 vs. 71/208, 65.9% vs. 34.1%), the CD34-MVD value was significantly different between the two groups (P<0.05). In addition, expressions of CEACAM1 and CD34 were significantly different from gastric adenocarcinoma to normal gastric tissues, respectively (P<0.05). High CEACAM1 expression and high MVD value were positively associated with lymph nodes metastasis and TNM stage, but negatively related to pathological grade (P<0.05). But they were irrelevant with tumor size, patients’ age and gender (P>0.05). ConclusionsThe up-regulation of CEACAM1 expression may participate in tumorous angiogenesis, especially high expression of CEACAM1 promoted its capability of invasion and metastasis.

Critical role of histone demethylase RBP2 in human gastric cancer angiogenesis

BackgroundThe molecular mechanisms responsible for angiogenesis and abnormal expression of angiogenic factors in gastric cancer, including vascular endothelial growth factor (VEGF), remain unclear. The histone demethylase retinoblastoma binding protein 2 (RBP2) is involved in gastric tumorgenesis by inhibiting the expression of cyclin-dependent kinase inhibitors (CDKIs).MethodsThe expression of RBP2, VEGF, CD31, CD34 and Ki67 was assessed in 30 human gastric cancer samples and normal control samples. We used quantitative RT-PCR, western blot analysis, ELISA, tube-formation assay and colony-formation assay to characterize the change in VEGF expression and associated biological activities induced by RBP2 silencing or overexpression. Luciferase assay and ChIP were used to explore the direct regulation of RBP2 on the promoter activity of VEGF. Nude mice and RBP2-targeted mutant mice were used to detect the role of RBP2 in VEGF expression and angiogenesis in vivo.ResultsRBP2 and VEGF were both overexpressed in human gastric cancer tissue, with greater microvessel density (MVD) and cell proliferation as compared with normal tissue. In gastric epithelial cell lines, RBP2 overexpression significantly promoted the expression of VEGF and the growth and angiogenesis of the cells, while RBP2 knockdown had the reverse effect. RBP2 directly bound to the promoter of VEGF to regulate its expression by histone H3K4 demethylation. The subcutis of nude mice transfected with BGC-823 cells with RBP2 knockdown showed reduced VEGF expression and MVD, with reduced carcinogenesis and cell proliferation. In addition, the gastric epithelia of RBP2 mutant mice with increased H3K4 trimethylation showed reduced VEGF expression and MVD.ConclusionsThe promotion of gastric tumorigenesis by RBP2 was significantly associated with transactivation of VEGF expression and elevated angiogenesis. Overexpression of RBP2 and activation of VEGF might play important roles in human gastric cancer development and progression.

Relationship between carcinoembryonic antigen-related cell adhesion molecule 1 expression and angiogenesis in gastric cancer

Objective To investigate the relationship between carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) expression and angiogenesis in gastric cancer.Methods CEACAM1 and CD34 expression was detected by immunohistochemistry (IHC) in 174 cases of gastric cancer and 40 cases of nonneoplastic gastric tissues.Results No CEACAM1 expression was found in nonneoplastic gastric mucosa tissues.CEACAM1 expression was classfied as high and low (69.0％ vs.31.0％),the CD34-microvessel density (MVD) expression between them was significantly different (57.32 ± 6.56 vs.44.26 ± 7.25,P ＜ 0.05).Coexpression of CEACAM1 and CD34-MVD was elevated and significantly different from nonneoplastic to neoplastic lesions(P ＜0.05).Moreover,high CEACAM1 expression and CD34-MVD were closely associated with degree of tumor differentiation,nodal metastasis and TNM staging.Conclusion Up-regulating CEACAM1 may participate in tumor angiogenesis,and promote its capability of invasion and metastasis. Key words: Gastric cancer; Carcinoembryonic antigen-related cell adhesion molecule 1; CD34 ; Immunohistochemistry

Expression of astrocyte elevated gene-1 closely correlates with the angiogenesis of gastric cancer.

Previous studies have demonstrated that astrocyte elevated gene-1 (AEG-1) is overexpressed in several cancer types and that its upregulation may promote cell proliferation, cell transformation and tumor progression. The present study investigated the expression and prognostic value of AEG-1 in primary gastric cancer (GC) as well as its role in angiogenesis. The results obtained from real-time reverse transcription polymerase chain reaction and western blotting revealed the upregulation of AEG-1 mRNA (P=0.007) and protein expression (P<0.001) in the majority of cancerous tissues compared with matched adjacent non-cancerous gastric tissues. To further investigate the clinicopathological and prognostic roles of AEG-1, immunohistochemical analysis of 216 GC tissue blocks was performed. The results showed that high AEG-1 expression closely correlated with differentiation degree (P<0.001 ), T stage (P<0.001), N stage (P=0.003) and M stage (P=0.013). Consistent with the abovementioned results, AEG-1 upregulation was also found to significantly correlate with poor survival in GC patients (P<0.001). Furthermore, carcinomas with elevated AEG-1 expression demonstrated high vascular endothelial growth factor (VEGF) expression and microvessel density, which was labeled by cluster of differentiation 34. In addition, an AEG-1 siRNA assay in MGC-803 cells showed that the AEG-1 gene may promote VEGF and hypoxia-inducible factor-1α protein and mRNA expression. The results of the current study indicated that AEG-1 may serve as a valuable prognostic marker for GC and may be involved in regulating tumor angiogenesis.

Correlation of tumor-associated macrophages with clinicopathologic factors and angiogenesis in gastric cancer.

54 Background: Tumor associated macrophages (TAMs) are major components of tumor environment, and polarized into M1 and M2 type. M1 has been known as antitumorigenic, whereas M2 as protumorigenic. M2 have a significant role in tumor progression by promoting tumor cell invasion, migration and angiogenesis. We evaluated the M2 macrophages to investigate its importance in predicting clinical outcome or prognosis, and the relationship between M2 and angiogenesis in patients with gastric cancer. Methods: Formalin-fixed, paraffin-embedded blocks were obtained from the 88 patients with gastric cancer. CD163+ TAMs and CD105+ vessels were evaluated by immunohistochemical staining and the extent of CD163+ TAMs in tumor were divided into three groups: (A) infiltrated TAMs in cancer cell nest (nest TAMs); (B) infiltrated TAMs in tumor stroma (stroma TAMs); and (C) infiltrated TAMs along the invasive margin of a tumor (margin TAMs). Results: The increased stroma and margin TAMs (&gt;72 and &gt;102, respectively) were closely correlated with lymph node metastasis, TNM stage and lymphatic invasion (p&lt;0.05 in 3 factors) and positive correlation existed between the stroma and margin TAMs (p&lt;0.001). Disease-free survival rate analyzed using the Kaplan– Meier method was significantly lower in patient with high stroma and margin TMAs than patient with low stroma and margin TAMs (p=0.0039 and 0.0499, respectively). CD105+ vessels showed significant correlation with lymph node metastasis and lymphatic invasion.(p=0.006 and p&lt;0.0001, respectively) Stromal, marginal and nest TAMs were positively correlated with CD105+ vessels (p=0.001). Conclusions: M2 infiltration in tumor stroma and tumor margin in gastric cancer showed relationship with aggressive phenotypes such as lymph node metastasis, TNM stage and lymphatic invasion and was correlated with angiogenesis. This study supports the view that the adverse prognostic impact of M2 involves tumor angiogenesis in gastric cancer.

The role of tumour microenvironment in gastric cancer angiogenesis.

Gastric cancer is one of the most common cancers in the world. More than 95% of gastric cancers are adenocarcinomas originating from the glandular epithelium of the stomach lining. Unfortunately, a large number of patients are diagnosed when the tumour is at unresectable stage. Therefore, it is very important to understand the mechanisms involved in gastric cancer pathogenesis. One of them is angiogenesis, which means the formation of new blood vessels from pre-existing vasculature. This process is dependent on interactions between the tumour and surrounding stromal cells which create the tumour microenvironment. Moreover, both tumour and stromal cells release a wide array of angiogenic factors that have an influence on endothelial cell recruitment and thus affect the process of angiogenesis. In this paper we discuss the role of tumour microenvironment in gastric cancer angiogenesis.