Angiogenesis, formation of new microvessels providing oxygen and nutrient supply, is essential for tumor growth. It is dependent on the production of angiogenic growth factors by tumor cells. Angiopoietin 1 (Ang-1) and 2 (Ang-2) and their common receptor, Tie2, are thought to be critical regulators of tumor angiogenesis. We examined expression of Ang-1, Ang-2, and their common receptor Tie2 mRNAs and proteins in gastric cancers using in situ hybridization and immunohistochemistry. We also investigated the relationship between their expression and differentiation of cancer cells, lymph node metastasis, tumor size, depth of cancer cell invasion, TNM staging and microvessel density (MVD). The expression of Ang-1, Ang-2, and Tie2 mRNA in cancer cells significantly correlated with the MVD (p<0.001, <0.001 and =0.019, respectively). Ang-1 and Tie2 positivity correlated with advanced gastric cancers (p<0.05) and larger cancers had higher positive rates of Ang-1, Ang-2, and Tie2 mRNA expression (p<0.001, =0.010 and =0.039, respectively). Significant positive correlations were also found between mRNA expression of Tie2 and those of Ang-1 and Ang-2 (p<0.01 and <0.001, respectively). These findings indicate that the expression of Ang-1 and Ang-2 is important for tumor angiogenesis, and suggest a possible role of autocrine/paracrine function of angiopoietin/Tie2 system in gastric cancer progression.
Stomach Neoplasms/blood supply/*genetics/*metabolism/pathology ; Receptor, TIE-2/*genetics/*metabolism ; RNA, Neoplasm/genetics/metabolism ; RNA, Messenger/genetics/metabolism ; Neovascularization, Pathologic ; Middle Aged ; Male ; In Situ Hybridization ; Immunohistochemistry ; Humans ; Gene Expression ; Female ; Carcinoma, Signet Ring Cell/blood supply/genetics/metabolism/pathology ; Angiopoietin-2/*genetics/*metabolism ; Angiopoietin-1/*genetics/*metabolism ; Aged ; Adult ; Adenocarcinoma/blood supply/genetics/metabolism/pathology

OBJECTIVETo investigate whether correlation exists between mRNA expression of IGF-II and hepatocyte growth factor (HGF) and tumor progression and prognosis in gastric cancer.

METHODSIn situ hybridization technique was used to examine mRNA expression of IGF-II and HGF, and immunohistochemical technique was used to examine protein expression of CD34 in 105 specimens of gastric carcinoma.

RESULTSIn situ hybridization revealed that the positive rates of IGF-II mRNA and HGFmRNA were 49.5% and 57.1%, respectively. In stage T3-T4 cases, positive mRNA expression rates of IGF-II and HGF, the frequencies of vessel invasion, lymph node metastasis and distant metastasis were significantly higher than those in stage T1-T2 cases. The mean microvascular density (MVD) in stage T3-T4 tumors, vessel invasion, lymph node metastasis and distant metastasis were significantly more frequent than those in stage T1-T2 tumors. The mean MVD in tumors with positive IGF-II and HGF expressions was significantly higher than that in tumors without IGF-II and HGF expression. There were positive correlations between MVD and expression of IGF-II and HGF. The mean survival time and 5-year survival rate in cases with positive IGF-II and HGF expression and MVD value > or = 39.5 were significantly shorter those that in cases with negative IGF-II and HGF expression and MVD value < 39.5.

CONCLUSIONIGF-II and HGF promote angiogenesis in gastric cancer, and take part in tumor invasion and metastasis. They can be used as prognostic markers of gastric cancer in clinical practice.

Adenocarcinoma, Papillary ; blood supply ; metabolism ; secondary ; Adult ; Aged ; Carcinoma, Ductal ; blood supply ; metabolism ; secondary ; Carcinoma, Signet Ring Cell ; blood supply ; metabolism ; secondary ; Disease Progression ; Female ; Hepatocyte Growth Factor ; biosynthesis ; genetics ; Humans ; Insulin-Like Growth Factor II ; biosynthesis ; genetics ; Liver Neoplasms ; blood supply ; metabolism ; secondary ; Lymphatic Metastasis ; Male ; Microcirculation ; Middle Aged ; Neoplasm Invasiveness ; Neovascularization, Pathologic ; Peritoneal Neoplasms ; blood supply ; metabolism ; secondary ; Prognosis ; RNA, Messenger ; biosynthesis ; genetics ; Stomach Neoplasms ; blood supply ; metabolism ; pathology ; Survival Rate

OBJECTIVETo investigate mRNA expression of integrin beta3 in gastric carcinoma, its correlation with microvascular density (MVD), growth-pattern, invasion, metastasis and prognosis.

METHODSIn situ hybridization and immunohistochemistry techniques were used to study the expression of integrin beta3 mRNA and CD34 protein in 105 gastric carcinoma specimens.

RESULTSIn situ hybridization revealed a 30% (6/20) positive rate of integrin beta3 mRNA in non-tumor gastric mucosa, which was significantly lower than that of the gastric cancer group (61.0%, 64/105, chi(2) = 8.85, P = 0.037); In infiltrating type cases (70.2%, 40/57), stage III - IV (72.1%, 44/61), lymphatic metastasis (68.6%, 48/70) and distant metastasis (85.7%, 36/42), the positive expression rates were significantly higher than those of the expanding type (chi(2) = 14.97, P = 0.002), stage I - II (chi(2) = 15.21, P = 0.015), non-lymphatic metastasis (chi(2) = 17.89, P = 0.025) and non-distant metastasis (chi(2) = 20.22, P = 0.005; chi(2) = 21.35, P = 0.035); its mean MVD was also significantly higher than that of the expanding type (t = 10.105, P = 0.001), stage I approximately II (t = 5.961, P = 0.001), non-lymphatic metastasis (t = 3.819, P = 0.01)and non-distant metastasis (t = 10.578, P = 0.001; t = 7.882, P = 0.001), respectively; The mean MVD (41.02 +/- 8.55)/0.72 mm(2) of the integrin beta3 mRNA positive expression group was significantly higher than (25.26 +/- 11.25)/0.72 mm(2) of the negative expression group. There was a positive relation between MVD and integrin beta3 mRNA expression in the tumor (r(s) = 0.316, P = 0.001). The mean survival time in cases with positive integrin beta3 mRNA expression or MVD value >or= 39.5 was significantly shorter than that in cases with negative expression or MVD value < 39.5.

CONCLUSIONSIntegrin beta3 expression correlates with enhanced tumor angiogenesis and may play a role in the invasion and nodal metastasis of gastric carcinoma, therefore it may serve as a prognostic marker of gastric cancer.

Adult ; Aged ; Disease Progression ; Female ; Humans ; Integrin beta3 ; genetics ; Male ; Middle Aged ; Neovascularization, Pathologic ; etiology ; Prognosis ; RNA, Messenger ; analysis ; Stomach Neoplasms ; blood supply ; metabolism ; pathology ; Survival Rate

OBJECTIVETo study the expressions and activities of Rho GTPases in hypoxia and its relationship with tumor angiogenesis.

METHODSThree tumor cell lines were used in this study: gastric cancer cell lines AGS, SGC7901 and hepatocellular carcinoma cell line HepG2. Expression level of Rac1 mRNA was detected by semi-quantitative RT-PCR. Activity of Rac1 was determined by pull-down assay and expression of HIF-1alpha, VEGF, p53 and PTEN protein was detected by Westernblot.

RESULTSThe expression level of Rac1 mRNA was significantly increased in hypoxia compared to normoxia. Pull-down assay showed that hypoxia-induced activity of Rac1 was elevated in a time-dependent manner and climaxed at 3 hours. The expressions of HIF-1alpha and VEGF protein were up-regulated, while those of PTEN and p53 protein were down-regulated.

CONCLUSIONThese results indicate that hypoxia enhances Rac1 expression which might be involved in tumor angiogenesis by reacting with hypoxia-responsive genes.

Cell Hypoxia ; Cell Line, Tumor ; Hepatoblastoma ; blood supply ; metabolism ; pathology ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; biosynthesis ; genetics ; Liver Neoplasms ; blood supply ; metabolism ; pathology ; Neovascularization, Pathologic ; PTEN Phosphohydrolase ; biosynthesis ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; Stomach Neoplasms ; blood supply ; metabolism ; pathology ; Tumor Suppressor Protein p53 ; biosynthesis ; genetics ; Vascular Endothelial Growth Factor A ; biosynthesis ; genetics ; rac1 GTP-Binding Protein ; biosynthesis ; genetics ; rho GTP-Binding Proteins ; biosynthesis ; genetics

OBJECTIVETo explore the effects of angiopoietins (Ang-1 and Ang-2) and Tie-2 expression on microvessel density (MVD) in gastric cancers.

METHODSBy using semiquantitative RT-PCR, immunohistochemistry and image analysis system, the expression of Ang-1, Ang-2, Tie-2 mRNA and their proteins were detected in 68 primary gastric cancers and their adjacent normal tissues. Microvessel density (MVD) was figured out based on CD34 immunohistochemical staining.

RESULTSThe expression of all Ang-1, Ang -2, Tie-2 mRNA and their proteins was detected in gastric cancers and their paired adjacent gastric mucosa tissues. A negative correlation between Ang-1 protein, Tie-2 mRNA and MVD in gastric cancers was observed (r = -0.440, r = -0.267; P < 0.05), while the relation between Ang-2 mRNA and its protein, Ang-2/Ang-1 protein ratio with MVD were positive (r = 0.319, r = 0.729, r = 0.739; P < 0.05). It was found that MVD in groups with Ang-2 mRNA T/N ratio over 1.2 (the ratio of Ang-2 mRNA in gastric cancers and its adjacent normal mucosa) was higher than that in those with a ratio under 1.2, revealed by analysing the effects of Ang-1 and Ang-2 mRNA T/N ratio on MVD in gastric cancers.

CONCLUSIONAng-1 activates Tie-2 receptor, whereas Ang-2 antagonizes Ang-1 in the angiogenesis, and the Ang-2/Ang-1 ratio determines angiogenesis and tumor growth in gastric cancers. When the expression of Ang-2 is high and Ang-1 is low, the angiogenesis in gastric cancers is promoted, otherwise oppositely. The role of Ang-2 is dominant in the effect of Angs and their receptor on angiogenesis in gastric cancers.

Angiopoietin-1 ; biosynthesis ; genetics ; Angiopoietin-2 ; biosynthesis ; genetics ; Female ; Humans ; Male ; Microcirculation ; pathology ; Middle Aged ; Neoplasm Staging ; Neovascularization, Pathologic ; etiology ; RNA, Messenger ; biosynthesis ; genetics ; Receptor, TIE-2 ; biosynthesis ; genetics ; Stomach Neoplasms ; blood supply ; metabolism ; pathology

OBJECTIVETo establish experimental models for tumor neovascularization and to apply quantitative digital imaging analysis in the study.

METHODSAn endothelial tube formation model was established by human umbilical vein endothelial cells (HUVECs). A vasculogenic mimicry model was established by SGC-7901 gastric cancer cell line. Fertilized eggs were used to establish a chorioallantoic membrane angiogenesis model. Using gene transfection experiment, IRX1 tumor suppressor gene was chosen as a therapeutic target. Image Pro Plus (IPP) analysis software was used for digital vascular images analysis with parameters including points, lines, angles and integral absorbance (IA) for the tubular formation or vasculogenic mimicry.

RESULTSDigital image analysis by IPP showed that HUVEC tubular formation was significantly inhibited in IRX1 transfectant, compared with controls. The tubular numbers in three groups were 12.80 +/- 3.83, 29.00 +/- 5.34 and 28.20 +/- 4.32 (P<0.01). The connection points of tubules in three groups were 13.20 +/- 2.59, 25.00 +/- 2.24 and 24.60 +/- 3.21 (P<0.01). The tubular lengths of three groups were (821.5 +/- 12.5), (930.9 +/- 13.5) and (948.4 +/- 18.1) microm (P=0.022). The IA values of PAS stain in three groups were 3606 +/- 363, 14 200 +/- 1251 and 15 043 +/- 1220 (P<0.01). In chick chorioallantoic membrane model, the angular numbers of tubules in three groups were 6.41 +/- 2.60, 10.27 +/- 2.65 and 9.18 +/- 1.99 (P<0.01).

CONCLUSIONSThe endothelial tube formation model, vasculogenic mimicry model and chorioallantoic membrane angiogenesis model are useful for gene therapy and drug screening with targeting neoplastic vascularization. Professional image analysis software may greatly facilitate the quantitative analysis of tumor neovascularization.

Animals ; Cell Line, Tumor ; Cells, Cultured ; Chorioallantoic Membrane ; blood supply ; Diagnostic Imaging ; methods ; Homeodomain Proteins ; genetics ; metabolism ; physiology ; Human Umbilical Vein Endothelial Cells ; Humans ; Neovascularization, Pathologic ; Neovascularization, Physiologic ; Software ; Stomach Neoplasms ; genetics ; metabolism ; pathology ; Transcription Factors ; genetics ; metabolism ; physiology ; Transfection

OBJECTIVETo investigate the role of human angiopoietin-1 (Ang1) in tumorigenesis and angiogenesis of human gastric cancer cell line SGC7901 in nude mice.

METHODSRecombinant human Ang1 sense or antisense eukaryotic expression vectors were constructed, and transfected by lipofectin into human gastric cancer line SGC7901. Stable transfectants were obtained respectively, namely 7Ang1+ for sense, 7Ang1- for antisense, and 7901P for empty vector transfected cells. Semiquantitative PCR and Western blot were employed to testify the transfection efficiency. Cell growth curve and cell cycle were observed by MTT assays or flow cytometry. In in vivo study, growth of SGC7901 xeno-transplant was observed in BALB/c nude mice. Microvessel density (MVD) was analyzed by immunohistochemistry for Factor VIII staining.

RESULTSStably transfected cell lines were established and decreased expression of Ang1 protein and mRNA in the antisense transfected SGC7901 cells was achieved. Tumorigenesis of 7Ang1- cells on day 30 days was significantly inhibited with decreased MVD as compared to that in 7901P and 7Ang1+ cells (P < 0.01).

CONCLUSIONAngiopoietin-1 plays an important role in tumorigenesis and angiogenesis of gastric cancer which can be partially abrogated by antisense technique.

Angiopoietin-1 ; biosynthesis ; genetics ; Animals ; Cell Line, Tumor ; DNA, Antisense ; genetics ; Genetic Vectors ; Humans ; Mice ; Mice, Nude ; Microcirculation ; pathology ; Neoplasm Transplantation ; Neovascularization, Pathologic ; RNA, Messenger ; biosynthesis ; genetics ; Stomach Neoplasms ; blood supply ; metabolism ; pathology ; Transfection

OBJECTIVETo investigate the effects of silencing heparanase (HPA) on growth, angiogenesis and metastasis of human gastric carcinoma transplanted in nude mice.

METHODSHuman gastric carcinoma SGC-7901 cells and those cells with silenced HPA (gastric carcinoma SGC-7901-HPA(-)) were separately transplanted subcutaneously in 6 nude mice. The time, size and speed of tumor growth were recorded. RT-PCR and Western-blot were used to detect the expression of HPA mRNA and protein in the subcutaneous tumors of the two groups. Immunohistochemical staining was used to detect microvessel density (MVD) in the subcutaneous tumors of the two groups. Cells of the subcutaneous transplanted tumors of the two groups were separately injected into the peritoneal cavity of nude mice, 6 mice each. The growth of metastatic tumors in nude mice was observed.

RESULTSHuman gastric carcinoma SGC-7901 cells and SGC-7901-HPA(-) cells were subcutaneously inoculated in nude mice, and tumors appeared at 4 days and 7 days after inoculation, respectively. The MVD was (20.69 ± 1.20)/HP and (11.35 ± 1.94)/HP, respectively (P < 0.05). The expressions of HPA mRNA and protein of the subcutaneously transplanted SGC-7901-HPA(-) tumor were decreased. Four voluminous metastatic tumors caused by SGC-7901 cells occurred in 3 mice in the liver, right kidney, omentum and intestine. Two smaller abdominal metastatic tumors of SGC-7901-HPA(-) cells were found in the liver and right kidney.

CONCLUSIONSilencing HPA can inhibit the tumor growth, angiogenesis and metastasis of human gastric cancer in nude mice. It suggests that HPA might become a new target for prevention and treatment of gastric cancer.

Adenocarcinoma ; blood supply ; enzymology ; genetics ; pathology ; secondary ; Animals ; Cell Line, Tumor ; Gene Silencing ; Glucuronidase ; biosynthesis ; genetics ; physiology ; Humans ; Kidney Neoplasms ; secondary ; Liver Neoplasms ; secondary ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Microvessels ; pathology ; Neoplasm Transplantation ; Neovascularization, Pathologic ; RNA, Messenger ; metabolism ; Stomach Neoplasms ; blood supply ; enzymology ; genetics ; pathology

Adenocarcinoma ; blood supply ; metabolism ; mortality ; secondary ; Adult ; Aged ; Female ; Humans ; Lymphatic Metastasis ; Male ; Microcirculation ; Middle Aged ; Neovascularization, Pathologic ; metabolism ; pathology ; Prognosis ; RNA, Messenger ; biosynthesis ; genetics ; Receptors, Cell Surface ; biosynthesis ; genetics ; Receptors, Urokinase Plasminogen Activator ; Stomach Neoplasms ; blood supply ; metabolism ; mortality ; pathology ; Survival Rate ; Vascular Endothelial Growth Factor A ; metabolism

OBJECTIVETo investigate relationship between expressions of hypoxia inducible factor-1alpha (HIF-1alpha) and insulin-like growth factor-II (IGF-II) as well as their correlation with angiogenesis and prognosis in gastric carcinoma.

METHODSHIF-1alpha and IGF-II mRNA expression were analyzed using in situ hybridization, microvessel density (MVD) was determined by anti-CD34 immunostaining in 118 cases gastric carcinoma.

RESULTSThe positive rates of HIF-1alpha mRNA and IGF-II mRNA were 49.2% and 47.4%, respectively. In stage T3-T4 cases, positive rates of HIF-1alpha and IGF-II mRNA expression, the frequencies of vessel invasion, lymph node and distant metastasis were significantly higher than those in stage T1-T2 cases. The mean MVD in stage T3-T4 tumors, vessel invasion, lymph node metastasis and distant metastasis were significantly more frequent than those in stage T1-T2 tumors. The mean MVD in tumors with positive HIF-1alpha and IGF-II mRNA expression was significantly higher than those in tumors without HIF-1alpha and IGF-II mRNA expression. The expression of HIF-1alpha was positively correlated with IGF-II mRNA. There were positive correlations between MVD and expression of HIF-1alpha and IGF-II mRNA, respectively. The mean survival time and 5-year survival rate in cases with positive HIF-1alpha and VEGF expression and MVD value >/= 41.5 were significantly shorter than those in cases with negative HIF-1alpha and VEGF expression and MVD value < 41.5.

CONCLUSIONSHIF-1alpha and IGF-II play an important role in tumor invasion and metastasis, especially in tumor angiogenesis. So test of the expression of HIF-1alpha and IGF-II may act as a useful index of treatment and prognosis.

Adult ; Aged ; Antigens, CD34 ; analysis ; Female ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; genetics ; metabolism ; Immunohistochemistry ; In Situ Hybridization ; Insulin-Like Growth Factor II ; metabolism ; Male ; Middle Aged ; Neovascularization, Pathologic ; genetics ; metabolism ; pathology ; Prognosis ; RNA, Messenger ; genetics ; metabolism ; Stomach Neoplasms ; blood supply ; genetics ; metabolism ; Survival Analysis