AIM: To evaluate the effects of sulindac in inducing growth inhibition and apoptosis of human gastric cancer cells in comparison with human hepatocellular carcinoma (HCC) cells. METHODS: The human gastric cancer cell ...AIM: To evaluate the effects of sulindac in inducing growth inhibition and apoptosis of human gastric cancer cells in comparison with human hepatocellular carcinoma (HCC) cells. METHODS: The human gastric cancer cell lines MKN45 and MKN28 and human hepatocellular carcinoma cell lines HepG(2) and SMMC7721 were used for the study. Anti-proliferative effect was measured by MTT assay, and apoptosis was determined by Hoechst-33258 staining, electronography and DNA fragmentation. The protein of cyclooxygenase-2 (COX-2) and Bcl-2 were detected by Western dot blotting. RESULTS: Sulindac could initiate growth inhibition and apoptosis of MKN45, MKN28, HepG(2) and SMMC7721 cells in a dose-and time-dependent manner. Growth inhibitory activity and apoptosis were more sensitive in HepG(2) cells than in SMMC7721 cells, MKN45 and MKN28 cells. After 24 hours incubation with sulindac at 2mmol x L(-1) and 4mmol x L(-1), the level of COX-2 and Bcl-2 protein were lowered in MKN45, SMMC7721 and HepG(2) cells but not in MKN28 cells. CONCLUSION: Sulindac could inhibit the growth of gastric cancer cells and HCC cells effectively in vitro by apoptosis induction, which was associated with regression of COX-2 and Bcl-2 expression. The growth inhibition and apoptosis of HCC cells were greater than that of human gastric cancer cells. The different effects of apoptosis in gastric cancer cells may be related to the differentiation of the cells.展开更多
AIM: To explore the expression and clinicopathological significance of cyclooxygenase-2 (COX-2) and microvessel density (MVD) in gastric carcinogenesis, and to investigate their roles in the invasion and the relations...AIM: To explore the expression and clinicopathological significance of cyclooxygenase-2 (COX-2) and microvessel density (MVD) in gastric carcinogenesis, and to investigate their roles in the invasion and the relationship between biological behaviors and prognosis of gastric cancer. METHODS: Using Envision immunohistochemistry, COX-2 and CD34 expressions in gastric cancer tissue array were examined. MVD was counted and the relationship between the biological behaviors and prognosis was analyzed. RESULTS: The expression of COX-2 in gastric cancer tissue was significantly higher than that in normal mucosa (χ2 = 12.191, P < 0.05). The over-expression of COX-2 in gastric cancer was obviously related to metastasis and depth of invasion (χ2 = 6.315, P < 0.05), but not related to the histological type and Borrmann type (χ2 = 5.391 and χ2 = 2.228, respectively). Moreover, MVD in gastric cancer tissues was significantly higher than that in the normal mucosa (65.49 ± 20.64 vs 36.21 ± 18.47, t/F = 7.53, P < 0. 05). MVD was related to the histologic type and metastasis (t/F = 3.68 and t/F = 4.214, respectively, P < 0. 05), but not related to the depth of invasion and Borrmann type (t/F = 0.583 and t/F = 0.459, respectively). MVD in COX-2-positive tissues was markedly higher compared to COX-2-negative tissues, indicating a positive correlation between COX-2 expression and MVD (t = 13.12, P < 0. 05). CONCLUSION: Tissue microarray (TMA) is a powerful tool for rapid identifi cation of the molecular alterations in gastric cancer. COX-2 expression, via inducingangiogenesis, may play an important role in gastric carcinogenesis. It could be served as a determinant factor for clinical prognosis and curative effect.展开更多
AIM: To examine the effects of Helicobacter pylori(Hpylori) infection on the invasiveness of gastric cancer cells,and to elucidate its mechanism. METHODS: Gastric carcinoma cells, MKN-45, were incubated with CagA-posi...AIM: To examine the effects of Helicobacter pylori(Hpylori) infection on the invasiveness of gastric cancer cells,and to elucidate its mechanism. METHODS: Gastric carcinoma cells, MKN-45, were incubated with CagA-positive H pylori, and cell invasion was determined by Matrigel analysis.The expression of matrix metallopr-oteinase-9 (MMP-9),vascular endothelial growth factor (VEGF), and cyclooxygenase-2 (COX-2) were assessed by Western-blot analysis, and transcriptional activation of the COX-2 promoter was examined by measuring luciferase and β-galactosidase activities. Lastly,the proteinDNA interaction was confirmed by an electrophoretic mobility shift assay. RESULTS: The current studies showed that: (1) incubation of CagA-positive H pylori with MKN-45 cells significantly promotes gastric cancer cells invasion, and this effect is attenuated by pre-treatment with NS-398, a COX-2 inhibitor, or PDTC,a nuclear factor κB (NF-κB) inhibitor;(2) the induction of MKN-45 cells invasion by Hpylori is associated with increases in COX-2, MMP-9, and VEGF protein expression, and co-incubation of NS-398 or PDTC significantly reduces these effects;(3) H pylori infection transactivates COX-2 promoter activity and increases the binding of NF-κB to this promoter. CONCLUSION: Our data demonstrate that H pylori infection promotes gastric epithelial cells invasion by activating MMP-9 and VEGF expression. These effects appear to be mediated through a NF-κB and COX-2 mediated pathway, as COX-2 or NF-κB inhibitor significantly attenuate the invasiveness of gastric cancer cells and the expressions of MMP-9 and VEGF protein.展开更多
AIM: To evaluate the effects of NS-398, a cyclooxygenase-2 (COX-2) inhibitor, on the proliferation and apoptosis of HepG2 cells. METHODS: The effects of NS-398 on the proliferation of HepG2 cells were evaluated by MTT...AIM: To evaluate the effects of NS-398, a cyclooxygenase-2 (COX-2) inhibitor, on the proliferation and apoptosis of HepG2 cells. METHODS: The effects of NS-398 on the proliferation of HepG2 cells were evaluated by MTT. DNA fragmentation gel analysis was used to analyze the apoptotic cells. DNA ploidy and apoptotic cell percentage were calculated by flow cytornetry. The expression of COX-2 and Bcl-2 mRNA was identified by competitive RT-PCR. Furthermore, expression level of Bcl-2 was detected using Western blot in HepG2 after treated with NS-398. RESULTS: NS-398 inhibited cell proliferation and induced apoptosis of HepG2 cells in a concentration-dependent manner. DNA ploidy analysis showed that S phase cells were significantly decreased with increase of NS-398 concentration. The quiescent GO/G1 phase was accumulated with decrease of Bcl-2 mRNA. Whereas NS-398 had no effect on the expression of COX-2 mRNA, and no correlations were found between COX-2 mRNA and HepG2 cell proliferation and apoptosis induced by NS-398 (r=0.056 and r=0.119, respectively). Bcl-2 protein level was inhibited after treated with NS-398. CONCLUSION: NS-398 significantly inhibits the proliferation and induces apoptosis of HepG2 cells. Mechanisms involved may be accumulation of quiescent GO/G1 phase and decrease of Bcl-2 expression.展开更多
AIM: To explore expression and distribution features of COX-2 and bcl-2 in human gastric adenocarcinoma tissues and to study its biological significance.METHODS: Totally 36 human gastric carcinoma samples were enrolle...AIM: To explore expression and distribution features of COX-2 and bcl-2 in human gastric adenocarcinoma tissues and to study its biological significance.METHODS: Totally 36 human gastric carcinoma samples were enrolled in this study (cardiac adenocarcinoma 16 cases, distal gastric adenocarcinoma 20 cases). The expressions of COX-2 and bcl-2 in cancerous tissues and corresponding para-cancerous tissues were investigated by immunohistochemistry using COX-2 polyclonal antibody and bcl-2 monoclonal antibody. The normal gastric mucosa tissues were used as control.RESULTS: The expressions of COX-2 and bcl-2 in gastric carcinoma were significantly higher than that in the paracancerous tissues (77.8% vs 47.2%, P＜0.01, 80.56% vs 58.33%, P＜0.05). The expression of COX-2 in cardiac adenocarcinoma was remarkably higher than that in the distal gastric carcinoma (93.8% vs 65.0%, P＜0.01). The expression of COX-2 was mainly localized in the cytoplasm of tumor cells and partly in the nucleus. There is a transition of the COX-2 cytoplasmic positivity to nucleic in tumor cells with the increase of gastric carcinoma pathological grade. Interstitial macrophages, fibroblasts and vascular endothelial cells also expressed COX-2. The tissues with higher expression of COX-2 also expressed high level of bcl-2 protein.CONCLUSION: Abnormal expression pattern of COX-2within the tissues of human gastric cancer is correlated with tumor location and lymph node metastasis. COX-2may regulate expression of apoptosis suppressor gene (bcl-2) through interaction of tumor cells and stromal cells and play an important role in the generation and development of tumors, which will be of great help in developing new methods for antitumor therapy.展开更多
Selective cyclooxygenase （COX）-2 inhibitors （coxibs） were developed as one of the anti-inflammatory drugs to avoid the various side effects of non-steroidal anti-inflammatory drugs （NSAIDs）. However, coxibs also...Selective cyclooxygenase （COX）-2 inhibitors （coxibs） were developed as one of the anti-inflammatory drugs to avoid the various side effects of non-steroidal anti-inflammatory drugs （NSAIDs）. However, coxibs also have an ability to inhibit tumor development of various kinds the same way that NSAIDs do. Many experimental studies using cell lines and animal models demonstrated an ability to prevent tumor proliferation of COX-2 inhibitors. After performing a randomized study for polyp chemoprevention study in patients with familial adenomatous polyposis （FAP）, which showed that the treatment with celecoxib, one of the coxibs, significantly reduced the number of colorectal polyps in 2000, the U.S. Food and Drug Administration （FDA） immediately approved the clinical use of celecoxib for FAP patients. However, some coxibs were recently reported to increase the risk of serious cardiovascular events including heart attack and stroke. In this article we review a role of COX-2 in carcinogenesis of gastrointestinal tract, such as the esophagus, stomach and colorectum, and also analyze the prospect of coxibs for chemoprevention of gastrointestinal tract tumors.展开更多
AIM: To clarify the significance of cyclooxygenase-2 (COX-2) expression in human primary hepatocellular carcinoma(HCC) and adjacent nontumorous tissues.METHODS: The COX-2 protein and mRNA were investigatedin 27 HCC ti...AIM: To clarify the significance of cyclooxygenase-2 (COX-2) expression in human primary hepatocellular carcinoma(HCC) and adjacent nontumorous tissues.METHODS: The COX-2 protein and mRNA were investigatedin 27 HCC tissues with adjacent nontumorous tissues, and 5histologically normal liver tissues, using immunohistochemistryand in situ hybridization.RESULTS: The well-differentiated HCC expressed COX-2protein (5.68±1.19) more strongly than moderated HCC(3.43± 1.98) and poor differentiated HCC (3.33± 1.50)(P＜0.05 respectively), adjacent nontumorous tissues (4.93±1.05) and normal liver tissues (3.20±1.g2) (P＜0.01respectively); More intensive staining of COX-2 in adjacentnontumorous tissues was observed than that in normal livertissues (P＜0.05). There was no significant difference amongadjacent nontumorous tissues, moderately differentiated HCCand poorly differentiated HCC (P＞0.05). The expression ofCOX-2 mRNA was observed in the cytoplasm of the cells ofHCC and of the hepatocytes in adjacent nontumorous tissuesin which COX-2 protein was positive.CONCLUSION: The overexpression of COX-2 in well-differentiated HCC suggests that COX-2 may play a role inthe early stages of hepatocarcinogensis.展开更多
基金Supported by Asahi Medical Foundation,No.00-2000-03
文摘AIM: To evaluate the effects of sulindac in inducing growth inhibition and apoptosis of human gastric cancer cells in comparison with human hepatocellular carcinoma (HCC) cells. METHODS: The human gastric cancer cell lines MKN45 and MKN28 and human hepatocellular carcinoma cell lines HepG(2) and SMMC7721 were used for the study. Anti-proliferative effect was measured by MTT assay, and apoptosis was determined by Hoechst-33258 staining, electronography and DNA fragmentation. The protein of cyclooxygenase-2 (COX-2) and Bcl-2 were detected by Western dot blotting. RESULTS: Sulindac could initiate growth inhibition and apoptosis of MKN45, MKN28, HepG(2) and SMMC7721 cells in a dose-and time-dependent manner. Growth inhibitory activity and apoptosis were more sensitive in HepG(2) cells than in SMMC7721 cells, MKN45 and MKN28 cells. After 24 hours incubation with sulindac at 2mmol x L(-1) and 4mmol x L(-1), the level of COX-2 and Bcl-2 protein were lowered in MKN45, SMMC7721 and HepG(2) cells but not in MKN28 cells. CONCLUSION: Sulindac could inhibit the growth of gastric cancer cells and HCC cells effectively in vitro by apoptosis induction, which was associated with regression of COX-2 and Bcl-2 expression. The growth inhibition and apoptosis of HCC cells were greater than that of human gastric cancer cells. The different effects of apoptosis in gastric cancer cells may be related to the differentiation of the cells.
文摘AIM: To explore the expression and clinicopathological significance of cyclooxygenase-2 (COX-2) and microvessel density (MVD) in gastric carcinogenesis, and to investigate their roles in the invasion and the relationship between biological behaviors and prognosis of gastric cancer. METHODS: Using Envision immunohistochemistry, COX-2 and CD34 expressions in gastric cancer tissue array were examined. MVD was counted and the relationship between the biological behaviors and prognosis was analyzed. RESULTS: The expression of COX-2 in gastric cancer tissue was significantly higher than that in normal mucosa (χ2 = 12.191, P < 0.05). The over-expression of COX-2 in gastric cancer was obviously related to metastasis and depth of invasion (χ2 = 6.315, P < 0.05), but not related to the histological type and Borrmann type (χ2 = 5.391 and χ2 = 2.228, respectively). Moreover, MVD in gastric cancer tissues was significantly higher than that in the normal mucosa (65.49 ± 20.64 vs 36.21 ± 18.47, t/F = 7.53, P < 0. 05). MVD was related to the histologic type and metastasis (t/F = 3.68 and t/F = 4.214, respectively, P < 0. 05), but not related to the depth of invasion and Borrmann type (t/F = 0.583 and t/F = 0.459, respectively). MVD in COX-2-positive tissues was markedly higher compared to COX-2-negative tissues, indicating a positive correlation between COX-2 expression and MVD (t = 13.12, P < 0. 05). CONCLUSION: Tissue microarray (TMA) is a powerful tool for rapid identifi cation of the molecular alterations in gastric cancer. COX-2 expression, via inducingangiogenesis, may play an important role in gastric carcinogenesis. It could be served as a determinant factor for clinical prognosis and curative effect.
基金Supported by the Taichung Veterans General Hospital Research Grant: TCVGH-933308C
文摘AIM: To examine the effects of Helicobacter pylori(Hpylori) infection on the invasiveness of gastric cancer cells,and to elucidate its mechanism. METHODS: Gastric carcinoma cells, MKN-45, were incubated with CagA-positive H pylori, and cell invasion was determined by Matrigel analysis.The expression of matrix metallopr-oteinase-9 (MMP-9),vascular endothelial growth factor (VEGF), and cyclooxygenase-2 (COX-2) were assessed by Western-blot analysis, and transcriptional activation of the COX-2 promoter was examined by measuring luciferase and β-galactosidase activities. Lastly,the proteinDNA interaction was confirmed by an electrophoretic mobility shift assay. RESULTS: The current studies showed that: (1) incubation of CagA-positive H pylori with MKN-45 cells significantly promotes gastric cancer cells invasion, and this effect is attenuated by pre-treatment with NS-398, a COX-2 inhibitor, or PDTC,a nuclear factor κB (NF-κB) inhibitor;(2) the induction of MKN-45 cells invasion by Hpylori is associated with increases in COX-2, MMP-9, and VEGF protein expression, and co-incubation of NS-398 or PDTC significantly reduces these effects;(3) H pylori infection transactivates COX-2 promoter activity and increases the binding of NF-κB to this promoter. CONCLUSION: Our data demonstrate that H pylori infection promotes gastric epithelial cells invasion by activating MMP-9 and VEGF expression. These effects appear to be mediated through a NF-κB and COX-2 mediated pathway, as COX-2 or NF-κB inhibitor significantly attenuate the invasiveness of gastric cancer cells and the expressions of MMP-9 and VEGF protein.
文摘AIM: To evaluate the effects of NS-398, a cyclooxygenase-2 (COX-2) inhibitor, on the proliferation and apoptosis of HepG2 cells. METHODS: The effects of NS-398 on the proliferation of HepG2 cells were evaluated by MTT. DNA fragmentation gel analysis was used to analyze the apoptotic cells. DNA ploidy and apoptotic cell percentage were calculated by flow cytornetry. The expression of COX-2 and Bcl-2 mRNA was identified by competitive RT-PCR. Furthermore, expression level of Bcl-2 was detected using Western blot in HepG2 after treated with NS-398. RESULTS: NS-398 inhibited cell proliferation and induced apoptosis of HepG2 cells in a concentration-dependent manner. DNA ploidy analysis showed that S phase cells were significantly decreased with increase of NS-398 concentration. The quiescent GO/G1 phase was accumulated with decrease of Bcl-2 mRNA. Whereas NS-398 had no effect on the expression of COX-2 mRNA, and no correlations were found between COX-2 mRNA and HepG2 cell proliferation and apoptosis induced by NS-398 (r=0.056 and r=0.119, respectively). Bcl-2 protein level was inhibited after treated with NS-398. CONCLUSION: NS-398 significantly inhibits the proliferation and induces apoptosis of HepG2 cells. Mechanisms involved may be accumulation of quiescent GO/G1 phase and decrease of Bcl-2 expression.
文摘AIM: To explore expression and distribution features of COX-2 and bcl-2 in human gastric adenocarcinoma tissues and to study its biological significance.METHODS: Totally 36 human gastric carcinoma samples were enrolled in this study (cardiac adenocarcinoma 16 cases, distal gastric adenocarcinoma 20 cases). The expressions of COX-2 and bcl-2 in cancerous tissues and corresponding para-cancerous tissues were investigated by immunohistochemistry using COX-2 polyclonal antibody and bcl-2 monoclonal antibody. The normal gastric mucosa tissues were used as control.RESULTS: The expressions of COX-2 and bcl-2 in gastric carcinoma were significantly higher than that in the paracancerous tissues (77.8% vs 47.2%, P＜0.01, 80.56% vs 58.33%, P＜0.05). The expression of COX-2 in cardiac adenocarcinoma was remarkably higher than that in the distal gastric carcinoma (93.8% vs 65.0%, P＜0.01). The expression of COX-2 was mainly localized in the cytoplasm of tumor cells and partly in the nucleus. There is a transition of the COX-2 cytoplasmic positivity to nucleic in tumor cells with the increase of gastric carcinoma pathological grade. Interstitial macrophages, fibroblasts and vascular endothelial cells also expressed COX-2. The tissues with higher expression of COX-2 also expressed high level of bcl-2 protein.CONCLUSION: Abnormal expression pattern of COX-2within the tissues of human gastric cancer is correlated with tumor location and lymph node metastasis. COX-2may regulate expression of apoptosis suppressor gene (bcl-2) through interaction of tumor cells and stromal cells and play an important role in the generation and development of tumors, which will be of great help in developing new methods for antitumor therapy.
文摘Selective cyclooxygenase （COX）-2 inhibitors （coxibs） were developed as one of the anti-inflammatory drugs to avoid the various side effects of non-steroidal anti-inflammatory drugs （NSAIDs）. However, coxibs also have an ability to inhibit tumor development of various kinds the same way that NSAIDs do. Many experimental studies using cell lines and animal models demonstrated an ability to prevent tumor proliferation of COX-2 inhibitors. After performing a randomized study for polyp chemoprevention study in patients with familial adenomatous polyposis （FAP）, which showed that the treatment with celecoxib, one of the coxibs, significantly reduced the number of colorectal polyps in 2000, the U.S. Food and Drug Administration （FDA） immediately approved the clinical use of celecoxib for FAP patients. However, some coxibs were recently reported to increase the risk of serious cardiovascular events including heart attack and stroke. In this article we review a role of COX-2 in carcinogenesis of gastrointestinal tract, such as the esophagus, stomach and colorectum, and also analyze the prospect of coxibs for chemoprevention of gastrointestinal tract tumors.
文摘AIM: To clarify the significance of cyclooxygenase-2 (COX-2) expression in human primary hepatocellular carcinoma(HCC) and adjacent nontumorous tissues.METHODS: The COX-2 protein and mRNA were investigatedin 27 HCC tissues with adjacent nontumorous tissues, and 5histologically normal liver tissues, using immunohistochemistryand in situ hybridization.RESULTS: The well-differentiated HCC expressed COX-2protein (5.68±1.19) more strongly than moderated HCC(3.43± 1.98) and poor differentiated HCC (3.33± 1.50)(P＜0.05 respectively), adjacent nontumorous tissues (4.93±1.05) and normal liver tissues (3.20±1.g2) (P＜0.01respectively); More intensive staining of COX-2 in adjacentnontumorous tissues was observed than that in normal livertissues (P＜0.05). There was no significant difference amongadjacent nontumorous tissues, moderately differentiated HCCand poorly differentiated HCC (P＞0.05). The expression ofCOX-2 mRNA was observed in the cytoplasm of the cells ofHCC and of the hepatocytes in adjacent nontumorous tissuesin which COX-2 protein was positive.CONCLUSION: The overexpression of COX-2 in well-differentiated HCC suggests that COX-2 may play a role inthe early stages of hepatocarcinogensis.
