Prognostic significance of expression of cyclooxygenase-2 and vascular endothelial growth factor in human gastric carcinoma

Prognostic significance of VEGF expression in correlation with COX-2, microvessel density, and clinicopathological characteristics in human gastric carcinoma

BACKGROUND

Many studies have shown that angiogenesis plays an important role in the process of cancer development and progression. Vascular endothelial growth factor (VEGF) has a potent angiogenic activity, and cyclooxygenase-2 (COX-2) supports angiogenesis by regulated production of angiogenic factors, including VEGF. The purpose of this study was to examine the expression of VEGF in combination with COX-2 and CD34, their correlation with various clinicopathological factors, and their prognostic significance in human gastric carcinoma.

METHODS

Specimens from 169 patients with different grade and stage gastric carcinoma were investigated by immunohistochemistry for COX-2 and VEGF expression. Tumor microvessel density was assessed with CD34 immunostaining. Correlations between the expression of VEGF, COX-2, CD34, and various clinicopathological factors were studied. The effect of these proteins on patient survival was determined.

RESULTS

COX-2 and VEGF were positively expressed in 36.7% and 50.3% of the patients, respectively. Positive correlation was found between VEGF and COX-2 and between VEGF and CD34. VEGF expression was correlated with depth of invasion; metastatic lymph nodes; lymphatic and venous invasion; and tumor, node, metastasis system stage. Patients with positive staining for VEGF showed far lower disease-free (64.9% vs. 81.3%) and overall (58.3% vs. 76.9%) survival rates than VEGF-negative patients. In multivariate analysis, only tumor location, depth of invasion, and lymph node metastasis were shown to be independent prognostic factors.

CONCLUSIONS

VEGF expression correlates with angiogenesis and tumor progression and is a valuable prognostic factor in patients with gastric carcinoma.

Modulation of mRNA stability as a novel therapeutic approach

During the last decade evidence has accumulated that modulation of mRNA stability plays a central role in cellular homeostasis, including cell differentiation, proliferation and adaptation to external stimuli. The functional relevance of posttranscriptional gene regulation is highlighted by many pathologies, wherein occurrence tightly correlates with a dysregulation in mRNA stability, including chronic inflammation, cardiovascular diseases and cancer. Most commonly, the cis-regulatory elements of mRNA decay are represented by the adenylate- and uridylate (AU)-rich elements (ARE) which are specifically bound by trans-acting RNA binding proteins, which finally determine whether mRNA decay is delayed or facilitated. Regulation of mRNA decay by RNA stabilizing and RNA destabilizing factors is furthermore controlled by different intrinsic and environmental stimuli. The modulation of mRNA binding proteins, therefore, illuminates a promising approach for the pharmacotherapy of those key pathologies mentioned above and characterized by a posttranscriptional dysregulation. Most promisingly, intracellular trafficking of many of the mRNA stability regulating factors is, in turn, regulated by some major signaling pathways, including the mitogen-activated protein kinase (MAPK) cascade, the AMP-activated kinase (AMPK) and the protein kinase (PK) C (PKC) family. In this review, we present timely examples of genes regulated by mRNA stability with a special focus on signaling pathways involved in the ARE-dependent mRNA decay. A better understanding of these processes may form the basis for the development of novel therapeutics to treat major human diseases.

MMP-2 but not MMP-9 associated with COX-2 and survival in gastric cancer

BACKGROUND AND AIM

Matrix metalloproteinases (MMPs) MMP-2 and MMP-9 can degrade type IV collagen of extracellular matrix and basal membranes. As cyclo-oxygenase-2 (COX-2) has been shown to activate MMPs, creating one of the COX-2-promoted pathways of tumour growth and metastasis, the prognostic role of MMP-2 and MMP-9 in gastric cancer was assessed and their association with COX-2 expression was evaluated.

MATERIALS AND METHODS

Samples were collected from 342 consecutive patients operated on for gastric cancer, of which 315 were acceptable for MMP-2, MMP-9 and COX-2 immunohistochemistry. Specimens were stained with specific antibodies, evaluated and categorised by two interpreters, and then correlated with clinical data and survival.

RESULTS

Epithelial MMP-2 immunoreactivity was associated with male sex, high stage, advanced penetration depth, non-curative surgery, high COX-2 expression and poor survival. Stromal MMP-2 expression correlated with high stage, intestinal type and non-curative surgery whereas MMP-9 correlated only with intestinal type. Stage, intent of surgery and COX-2 were independent prognostic factors.

CONCLUSIONS

Epithelial MMP-2 expression in gastric cancer is associated with aggressive forms, COX-2 and poor survival, although MMP-2 was not an independent prognostic factor. In gastric cancer tumour growth is apparently induced by COX-2, and invasion is mediated by MMP-2.

Effect of Ezhu on expression of cyclooxygenase, vascular endothelial growth factor and prostaglandin E2 in human gastric cancer cell line SGC7901

AIM: To investigate the effect of Ezhu on the expression of cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), vascular endothelial growth factor (VEGF) and prostaglandin E₂ (PGE₂) in human gastric cancer cell line SGC7901.

METHODS: The MTT method was used to observe the suppression of the human gastric cancer (SGC7901) cells treated with Ezhu. By drawing the suppression rate curves, we selected the appropriate Ezhu concentration at the 25% proliferation suppression rate as experimental concentration. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were adopted, respectively, to examine the expression of COX gene and protein. Furthermore, ELISA method was used to detect the variation of the VEGF and PEG₂ expression in culture medium.

RESULTS: Ezhu definitely inhibited the proliferation of human gastric cancer cells in a concentration dependent manner. Electrophoresis of the RT-PCR products demonstrated the expression of COX-1 and COX-2 gene in the human gastric cancer cells. Gray scale analysis showed that both Ezhu and celecoxib inhibited the expression of COX-1 and COX-2 gene, and the inhibitory action of Ezhu was greater than celecoxib. However, Western blot clearly showed that a specific protein strip was observed in COX-1 group at the 70 kDa, while in COX-2 group at the 80 kDa. Gray scale analysis confirmed than both Ezhu and celecoxib had apparent suppression on COX-2 protein, but had no effect on COX-1. Moreover, the suppression function of Ezhu surpassed celecoxib. Ezhu and celecoxib obviously degraded the content of VEGF in gastric cancer cells. In comparison with those in the control group, the results are statistically significant (91.0 ± 18.2, 127.8 ± 12.1 ng/L vs 162.0 ± 15.1 ng/L, P < 0.01). The level of PGE₂ in the cells treated with celecoxib was lower than the control group with no statistical significance. Nevertheless, Ezhu decreased the level of PGE₂ significantly (67.5 ± 6.9 ng/L vs 78.7 ± 5.6 ng/L, P < 0.01).

CONCLUSION: Ezhu can inhibit COX-2 and its downstream expression of PGE₂, and down-regulates VEGF expression, so as to suppress the proliferation of gastric cancer cells.

Cyclooxygenase-2 is an independent prognostic factor in gastric cancer and its expression is regulated by the messenger RNA stability factor HuR

PURPOSE

Cyclooxygenase-2 (COX-2) promotes carcinogenesis and its expression associates with clinicopathologic characteristics in gastric cancer. HuR is an mRNA binding protein that controls the stability of certain transcripts including COX-2. We evaluated the prognostic significance of COX-2 and HuR expressions in gastric cancer and whether there exists a link between HuR and COX-2 expressions.

EXPERIMENTAL DESIGN

The study included 342 consecutive patients with histologically confirmed gastric adenocarcinoma, of whom 321 patients had tissue specimens available for COX-2 and 316 for HuR immunohistochemistry. Specimens were stained by COX-2- and HuR-specific monoclonal antibodies and scored by two independent observers. Correlation to clinical data and survival was assessed. TMK-1 gastric adenocarcinoma cells were treated with small interfering RNA against HuR and expressions of HuR and COX-2 were detected by immunofluorescence and Western blot analysis.

RESULTS

Patients with low COX-2 expression had a cumulative 5-year survival of 53% and those with high COX-2 expression had 16% (P < 0.0001). In multivariate analysis, COX-2 was an independent prognostic factor (P = 0.003). Cytoplasmic HuR expression was associated with high COX-2 expression (P < 0.0001) and with reduced survival (P = 0.004) whereas nuclear positivity for HuR was not. When TMK-1 cells were treated with HuR small interfering RNA, expressions of HuR and COX-2 were reduced.

CONCLUSIONS

High COX-2 is an independent prognostic factor in gastric cancer. Cytoplasmic expression of HuR associates with high COX-2 expression and with reduced survival, and tissue culture experiments show that HuR can regulate expression of COX-2 in gastric cancer cells.

Cyclooxygenase-2 expression correlates with poor prognosis in pancreatic cancer

BACKGROUND

Cyclooxygenase-2 (COX-2) overexpression is related to poor outcome in several cancers. COX-2 is upregulated in 42-90% of pancreatic ductal adenocarcinomas and is a potential target for chemotherapy. Earlier studies have not shown the expression of COX-2 to be a prognostic factor in pancreatic cancer.

OBJECTIVE

To evaluate the prognostic value of COX-2 in a series of patients with pancreatic adenocarcinoma.

METHODS

128 patients operated on for pancreatic adenocarcinoma at Helsinki University Central Hospital between 1974 and 1998 provided sections from primary tumours which were immunohistochemically stained with a COX-2-antihuman monoclonal antibody.

RESULTS

Cytoplasmic COX-2 reactivity (>5%) occurred in 46 specimens (36%), correlating neither with age, sex, stage, size, tumour stage, nodal metastases, nor grade. Lack of COX-2 expression correlated with distant metastases (p = 0.026). In univariate survival analysis, COX-2 expression (p = 0.0114), stage (p = 0.0002), grade (p = 0.0001), and age (p = 0.042) had prognostic significance. One, two, and five year survival rates were 51%, 32%, and 8% in the COX-2 negative groups compared with 34%, 5%, and 5% in the COX-2 positive groups (p = 0.011). Prognostic significance was especially high for patients operated on with curative intent (p = 0.004). In multivariate analysis, COX-2 was an independent prognostic factor (hazard ratio = 1.6 (95% confidence interval, 1.1 to 2.3)).

CONCLUSIONS

Expression of COX-2 was associated with poor outcome from pancreatic ductal adenocarcinoma and was independent of tumour stage, grade, or age in multivariate analysis.

Transfection of mouse macrophage metalloelastase gene into murine CT-26 colon cancer cells suppresses orthotopic tumor growth, angiogenesis and vascular endothelial growth factor expression

A cDNA fragment coding for domains I and II of mouse macrophage metalloelastase (MME) was transfected into murine CT-26 colon cancer cells that are MME deficient. An orthotopic implantation model was established by using MME-transfected cells. In MME-transfected primary tumors, it demonstrated that tumor growth and microvessel formation were significantly inhibited compared with the controls. The expression of vascular endothelial growth factor (VEGF) mRNA and protein was significantly lower in MME-transfected group compared with those in the controls. Our data show that both MME and VEGF gene expression is highly associated with the vascularity of tumors, which may depend on a balance between MME and VEGF expression.

Expression of Cyclooxygenase-2 Is Regulated by Glycogen Synthase Kinase-3β in Gastric Cancer Cells

Cyclooxygenase-2 (COX-2) expression is a marker of poor prognosis in gastric cancer patients, and its inhibition suppresses gastric tumorigenesis in experimental animal models. The mechanism that leads to COX-2 overexpression in this tumor type is unknown. We have now shown that inhibition of phosphatidylinositol 3-kinase by LY294002 suppresses both basal and phorbol myristate acetate-induced COX-2 expression in TMK-1 and MKN-28 gastric cancer cells. Furthermore, inhibition of glycogen synthase kinase-3beta (GSK-3beta) by SB415286 induced expression of COX-2 mRNA and protein as well as the enzyme activity in the gastric cancer cells. The effect of SB415286 was confirmed by the use of two additional GSK-3beta inhibitors, lithium chloride and SB216763. SB415286 had a modest 1.6-fold stimulatory effect on a 2-kb COX-2 promoter reporter construct, but more importantly, it was shown to block the decay of COX-2 mRNA. In contrast to modulation of phosphatidylinositol 3-kinase/Akt/GSK-3beta pathway, inhibitors of mitogen-activated protein kinases (MEK 1/2, p38, JNK) or the mammalian target of rapamycin did not alter COX-2 expression in gastric cancer cells. Our data show that inhibition of GSK-3beta stimulates COX-2 expression in gastric cancer cells, which seems to be primarily facilitated via an increase in mRNA stability and to a lesser extent through enhanced transcription.

Anti-angiogenic treatment of gastrointestinal malignancies

The scientific rationale to block angiogenesis as a treatment strategy for human cancer has been developed over the last 30 years, but is only now entering the clinical arena. Preclinical studies have demonstrated the importance of the vascular endothelial growth factor (VEGF) pathways in both physiologic and pathologic angiogenesis, and have led to the development of approaches to block its role in tumor angiogenesis. Bevacizumab is an antibody to VEGF and has been shown to prolong survival when given with chemotherapy in the treatment of metastatic colorectal cancer (CRC). Although this is the first anti-angiogenic treatment to be approved for the treatment of human epithelial malignancy, a number of other approaches currently are in development. Soluble chimeric receptors to sequester serum VEGF and monoclonal antibodies against VEGF receptors have both shown considerable promise in the laboratory and are being brought into clinical investigation. A number of small-molecule tyrosine kinase inhibitors that have activity against VEGF receptors also are in clinical trials. Although these novel treatments are being pioneered in CRC, anti-angiogenic approaches also are being tested in the treatment of other gastrointestinal malignancies. Anti-VEGF therapy has shown promise in such traditionally resistant tumors as pancreatic cancer and hepatocellular carcinoma. This review will examine the preclinical foundation and then focus on the clinical studies of anti-VEGF therapy in gastrointestinal cancers.

Endogenous stimulators and inhibitors of angiogenesis in gastrointestinal cancers: basic science to clinical application

Progression of cancer is dependent on acquisition of vascular networks within the tumor. Tumor angiogenesis is dependent on up-regulation of angiogenesis stimulators to overcome the endogenous anti-angiogenic barrier. Such disruption of angiogenesis balance to favor neovascularization is a key step for progression of tumor growth and metastasis. In this regard, the vascular basement membrane and the extracellular matrix have been found to be rich sources of angiogenesis stimulators and inhibitors that become bioavailable on proteolysis of the matrix by tumor microenvironment-related enzymes. In this review the subgroup of endogenous angiogenesis stimulators and inhibitors is discussed, and their mechanism of action during tumor angiogenesis is evaluated. The role in regulating tumor growth and the possibility of using them as prognostic markers for human gastrointestinal cancers is discussed. Furthermore, we specifically address the role of vascular endothelial growth factor in human gastrointestinal cancers and discuss the development and use of bevacizumab (Avastin; anti-vascular endothelial growth factor antibody [Genentech, CA]) in the treatment of colorectal and other gastrointestinal cancers.

Is the hypoxia-inducible factor pathway important in gastric cancer?

Tumour hypoxia is well recognised in oncology to be a key factor resulting in treatment resistance and poor prognosis. Hypoxia leads to the expression of a number of gene products that are involved in tumour progression, invasion and metastasis formation. The most important of these proteins is thought to be hypoxia-inducible factor-1alpha (HIF-1alpha), which appears to be a master regulator of the cellular response to hypoxia. HIF-1alpha expression is associated with a poor prognosis and treatment response in a number of tumour sites. There is some evidence that the HIF-1alpha pathway might be involved in gastric carcinogenesis. Studies have shown reactive oxygen species from Helicobacter pylori, associated with the development of gastric cancer, stabilise HIF-1alpha. Non-steroidal anti-inflammatory drugs, shown to reduce the risk of gastric cancer, can decrease HIF-1alpha expression. Although a large study correlating HIF-1alpha expression with prognosis is lacking in gastric cancer, the immunohistochemical expression of HIF-1alpha target genes (Glut-1, VEGF, CA9, iNOS) is associated with a poor prognosis. In addition, the targeted inhibition of HIF-1alpha has been shown to inhibit the growth of gastric tumours in animals. Increased understanding of the importance of hypoxia and the HIF-1alpha pathways may therefore hold the key to prevention strategies, improved selection of patients for adjuvant therapy and new treatments for the disease.

Effects of COX-2 inhibitor on growth of human gastric cancer cells and its relation to hepatocyte growth factor

It is known that hepatocyte growth factor binding to its receptor regulates gastric cancer progression and metastasis. HGF was found to up-regulate the expression of cyclooxygenase-2 gene and increases prostaglandin (PG) synthesis in gastric mucosa cells. Overexpression of COX-2 and increased PG secretion have also been found to be involved in the regulation of growth and metastasis of gastric cancer. Results from this study showed that c-Met and COX-2 are expressed in 28 cases (93.3%) and 16 cases (53.3%) of 30 human gastric cancer tissues, respectively. Expressions of c-Met positively correlated with that of COX-2 (r=0.41; P=0.024). Using in vivo and in vitro models to further examine the interaction between c-MET and COX-2, we found that HGF stimulated the growth of SC-M1 cells in a dose-dependent manner. COX-2-specific inhibitor-NS398 inhibited the growth of human gastric cancer SC-M1 cells as well as HGF stimulated the growth of SC-M1 cells in a dose-dependent manner. HGF treatment of SC-M1 cells increased the secretion of PGE2 and this stimulation was blocked by NS398. In vivo SC-M1 tumor model showed that HGF stimulated the tumor growth and NS398 retarded the tumor growth. These results suggest that COX-2-specific inhibitors may play some role on the therapy of gastric cancer patients with high serum HGF level and overexpression of c-Met in tumor.

Cyclooxygenase-2 overexpression is associated with a poor outcome in resected ampullary cancer patients

PURPOSE

To identify potential prognostic molecular factors in ampullary adenocarcinoma that could be of significant importance. To this end, we examined the possible prognostic significance of cyclooxygenase-2 (Cox-2) and Survivin expression and the apoptotic index in a cohort of uniformly treated patients with ampullary cancer treated with radical surgical excision.

EXPERIMENTAL DESIGN

The entry criteria were that the patients have a pathologic diagnosis of ampullary cancer which had been resected. Expression analysis for Cox-2 and Survivin was done by immunohistochemical staining. Apoptotic cells were identified by the terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) method.

RESULTS

Thirty-nine tumor specimens from resected ampullary adenocarcinoma patients were included. By univariate analysis, overall survival was affected by Cox-2 expression and TUNEL staining (respectively, P = 0.0003 and 0.03). Survivin expression did not influence the overall survival in our patient population (P = 0.123). Patients' clinicopathologic features (gender, age, and T and N factors) did not influence outcome. In multivariate Cox regression analysis, Cox-2 expression (relative risk, 4.330; P = 0.005) was the only variable that significantly affected overall survival.

CONCLUSIONS

The results of the present article provide, for the first time, evidence that Cox-2 expression, but not Survivin expression, may represent a significant prognostic factor after surgical resection in patients affected by cancer of the ampulla of Vater. Further studies are required to determine whether Cox-2 inhibitors may be useful for the therapy or prevention of ampullary carcinoma.

Expression of activated signal transducer and activator of transcription 3 predicts expression of vascular endothelial growth factor in and angiogenic phenotype of human gastric cancer

PURPOSE

Angiogenic behavior is a critical aspect of cancer biology and subject to regulation by multiple molecular pathways. Because the signal transducer and activator of transcription 3 (Stat3) transcription factor regulates multiple genes important to angiogenesis, we sought to determine whether Stat3 expression is related to vascular endothelial growth factor (VEGF) expression and microvessel density (MVD) in gastric cancer and whether these factors predict survival in gastric cancer patients.

EXPERIMENTAL DESIGN

The expression of Stat3 and VEGF was determined by immunohistochemistry using archival tissues from 86 cases of resected human gastric cancer and confirmed by Western blot analysis. Angiogenic phenotype was determined by CD34 staining and microvessel counting.

RESULTS

Stat3 expression correlated with VEGF expression and MVD. In univariate survival analyses, Stat3 expression (P = 0.013) and MVD (P = 0.036) were associated with inferior survival. However, when Stat3 expression, VEGF expression, MVD, stage, completeness of resection, Lauren's histologic classification, and age were entered into a Cox proportional hazards model, only strong Stat3 expression (P = 0.049) and advanced stage (P < 0.01) were independently prognostic of poor survival. Furthermore, genetically enforced alterations of activated Stat3 expression led to altered VEGF expression and angiogenic potential in human gastric cancer cells.

CONCLUSION

Dysregulated Stat3 activation may play an important role in VEGF overexpression and elevated angiogenic phenotype in gastric cancer and contribute to gastric cancer development and progression.

Coexpression of cyclooxygenase-2 and thymidine phosphorylase as a prognostic indicator in patients with FIGO stage IIB squamous cell carcinoma of uterine cervix treated with radiotherapy and concurrent chemotherapy

PURPOSE

To evaluate the prognostic significance of thymidine phosphorylase (TP) and coexpression of cyclooxygenase-2 (COX-2)/TP, and to investigate the relationship between COX-2 and TP expression in squamous cell carcinoma of the uterine cervix.

METHODS AND MATERIALS

Cancer specimens from 75 patients with International Federation of Gynecology and Obstetrics Stage IIB squamous cell carcinoma of the uterine cervix who had undergone radiotherapy and concurrent chemotherapy were immunohistochemically stained with COX-2 and TP antibodies and scored. The prognostic significance of their expression status, and the relationship between COX-2 and TP was investigated.

RESULTS

TP predominantly stained cytoplasm and the cell membrane of the tumor cells mainly in a diffuse and intense manner. TP was negative (<10% distribution) in 17%, 1+ (10-50%) in 25%, and 2+ (>50%) in 57% of patients. TP overexpression was related to a marginal prognostic significance of a poor 5-year overall survival (p = 0.082, log-rank test) and a high locoregional recurrence rate (p < 0.1, chi-square test). COX-2 and TP coexpression was observed in 24% of patients and was significantly related to poor 5-year disease-free and overall survival rates (p = 0.0083 and p = 0.025, respectively), a high pelvic lymph node involvement rate, a poor response to treatment, and a greater incidence of locoregional recurrence (p < 0.05). By multivariate analyses, only COX-2, TP, and coexpression of COX-2/TP were significant independent prognostic indicators of patient survival. All tumors showed 1+ or 2+ TP expression when COX-2 was positive, and no tumor expressed COX-2 when TP was negative (p = 0.03). In contrast, 77% of tumors expressed 1+ or 2+ TP without the synchronous expression of COX-2.

CONCLUSIONS

Thymidine phosphorylase expression or COX-2/TP coexpression may be used as a molecular prognostic marker for squamous cell carcinoma of the uterine cervix. TP appears to be an important downstream molecule of COX-2 during angiogenesis and may be a new target for the treatment of uterine cervical cancer.

Apoptotic and anti-angiogenic strategies in liver and gastrointestinal malignancies

Inappropriate suppression of apoptosis is strongly implicated in tumorigenesis. Tumor development is heralded by the mutation of tumor suppressor genes and overexpression of anti-apoptotic genes permitting cell survival. Thus, inducing the apoptotic process in various ways can be applied to cancer management. Besides, angiogenesis is a crucial process for tumor growth and metastasis. New strategies targeting fundamental play-markers of the angiogenic process are currently under investigation.

Cyclooxygenase-2 protein levels are independent of epidermal growth factor receptor expression or activation in operable non-small cell lung cancer

Both cyclooxygenase (COX)-2 and epidermal growth factor receptor (EGFR) are thought to play important roles in the pathogenesis of non-small cell lung cancer (NSCLC). A number of in vitro studies have postulated a link between EGFR activation and subsequent COX-2 upregulation. The relationship between these factors has not been established in patients with NSCLC. COX-2 and EGFR expression were studied in 172 NSCLC specimens using standard immunohistochemical techniques. Western blotting was used to determine COX-2 and EGFR levels in five NSCLC cell lines. The effect of treatment with EGF on COX-2 expression in A549 cells was assessed.

RESULTS

Both EGFR and COX-2 are overexpressed in NSCLC. The predominant pattern of COX-2 and EGFR staining was cytoplasmic. Membranous EGFR staining was seen in 23.3% of cases. There was no relationship between COX-2 and EGFR expression and survival or any clinicopathological features. No correlation was seen between EGFR expression and COX-2 expression in the immunohistochemical series or in the cell lines. Treatment with EGF did not upregulate COX-2 levels in A549 cells, either in serum free or serum-supplemented conditions.

CONCLUSIONS

Although COX-2 and EGFR are over-expressed in NSCLC neither was of prognostic significance in this series of cases. There is no correlation between these two factors in either tumour samples or cell lines. Although these factors show no correlation in NSCLC, they remain potential, though independent targets for treatment.

Expression and clinical significance of vascular endothelial growth factor, cyclooxygenase-2, and Bcl-2 in borderline ovarian tumors

OBJECTIVE

The objectives were to study the expression of vascular endothelial growth factor (VEGF), cyclooxygenase-2 (Cox-2), and Bcl-2 in borderline ovarian tumors (BOTs) and the relationship within them, and to investigate the correlation between expression of VEGF, Cox-2, and Bcl-2, and the clinicopathologic features of BOTs.

METHODS

An immunohistochemical technique was used to investigate the expression of VEGF ,Cox-2, and Bcl-2 in 69 borderline, 18 benign, and 27 malignant human ovarian tumor tissues.

RESULTS

Expression rate of VEGF protein (59.4%) in BOTs was higher than in benign tumors (27.8%) and was lower than in ovarian carcinomas (92.6%), and there was a significant difference between BOTs and benign ovarian tumors (p < 0.05), and carcinoma (p < 0.01). Significant correlation was observed between the positive expression rate for VEGF and clinical stage of BOTs (p < 0.05). The statistical analysis did not show a close correlation between the expression of VEGF and tissue type, and peritoneal implants in BOTs (p > 0.05). The expression rate of Cox-2 was significantly higher in ovarian carcinomas (81.5%) than in BOTs (57.9%) and in benign ovarian tumors (38.9%) (p < 0.05). Significant correlation was observed between the positive expression rate for Cox-2 and the clinical stage of BOTs (p < 0.05). The statistical analysis showed no close correlation between the expression of Cox-2 and tissue type, and peritoneal implants in BOTs (p > 0.05). There was a significant difference between the expression of Bcl-2 in ovarian carcinomas and BOTs than that in benign ovarian tumors (p < 0.05). The positive expression rate of Bcl-2 was not related to clinical stages and peritoneal implants (p > 0.05). Statistical analysis showed a positive correlation between the expression of Cox-2 and VEGF, and Bcl-2 in BOTs.

CONCLUSIONS

Overexpression of VEGF, Cox-2, and Bcl-2 in BOTs may play an important role in the oncogenesis and progression of BOTs. It is feasible to detect VEGF, Cox-2, and Bcl-2 in the diagnosis and to predict the prognosis of BOTs.

Cyclooxygenase-2 Expression

PURPOSE

Recent studies have shown that cyclooxygenase (Cox)-2 may be involved in colorectal carcinogenesis. We aimed to determine whether Cox-2 expression in itself can predict outcome of colorectal cancer patient after surgery. In addition, the expression of Cox-1 was also evaluated.

EXPERIMENTAL DESIGN

Tissue samples of primary and secondary tumors from 288 patients undergoing surgical resections for colorectal adenocarcinoma were immunohistochemically examined for Cox-2 and Cox-1 expressions. The specimens were graded based on the intensity and extent of staining; then, the correlations between Cox-2 and Cox-1 expressions with clinicopathologic parameters and survival time were analyzed.

RESULTS

Expression of Cox-2 was positive in 70.8% of primary tumor, 92.0% of lymph node metastases, 100.0% of hepatic metastases, and was significantly associated with tumor size, depth of invasion, lymph node metastasis, vessels invasion, stage and recurrence. In contrast, Cox-1 was positive in 42.7% of primary tumor, 84.0% of lymph node metastases, 37.5% hepatic metastases, and was associated with only tumor size. Patients with Cox-2-positive tumors had a significant shorter survival time than those with negative tumors did (P = 0.0006 by log-rank test); and, in a multivariate analysis, Cox-2 was an independent prognostic factor (P = 0.0103; relative risk 4.114; 95% confidence interval, 1.397-12.120). Cox-1 status had no statistically effect on patient survival time.

CONCLUSIONS

Elevated Cox-2 expression, but not that of Cox-1, was significantly associated with reduced survival and recognized as an independent prognostic factor in our cohort of colorectal cancer patients.

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Prognostic significance of vascular endothelial growth factor and cyclooxygenase 2 expression in patients receiving preoperative chemoradiation for esophageal cancer

OBJECTIVE

Both vascular endothelial growth factor and cyclooxygenase 2 overexpression have been associated with poor prognosis in a variety of human malignancies. In this study we assessed the effect of preoperative chemotherapy and radiation on expression levels of vascular endothelial growth factor and cyclooxygenase 2 in patients with esophageal cancer and determined whether these markers were associated with treatment response and overall survival.

METHODS

Expression levels of vascular endothelial growth factor and cyclooxygenase 2 were measured in a cohort of 46 patients with esophageal cancer receiving preoperative chemoradiation followed by surgical resection. Immunohistochemical stains were performed on both pretreatment biopsy specimens and posttreatment resection specimens for each patient. Differences in vascular endothelial growth factor and cyclooxygenase 2 expression before and after treatment were measured, and pretreatment expression levels were correlated with treatment response and overall survival.

RESULTS

We found that preoperative chemotherapy and radiation induced expression of cyclooxygenase 2 in stromal cells and induced vascular endothelial growth factor expression in both tumor and stromal cells. Pretreatment vascular endothelial growth factor expression did not correlate with treatment response, and cyclooxygenase 2 expression correlated with treatment response only in the subset of patients with squamous cell carcinoma. Although patients whose tumors expressed high levels of vascular endothelial growth factor and cyclooxygenase 2 tended to have shorter overall survival times, this trend did not reach statistical significance.

CONCLUSIONS

Neither vascular endothelial growth factor nor cyclooxygenase 2 are strong predictors of treatment response and survival in patients undergoing preoperative chemoradiation for esophageal cancer. This lack of prognostic significance might be explained by changes in the expression levels of these markers during treatment.

Effects of COX-2 inhibitor with cisplatin on proliferation and apoptosis of pancreatic cancer cells

AIM: To investigate the effects of proliferation and apoptosis induced by cyclooxygenase-2 (COX-2) inhibitor celecoxib in combination with cisplatin.

METHODS: The human pancreatic cancer cell line BxPC-3 cells were treated with COX-2 inhibitors celecoxib and cisplatin. The cell relative viability was examined using 3 (4, 5-dimethylethiazoly 1-2-) 2, 5-diphonyl tetrazolium bromide (MTT) assays. the expression of COX-2 mRNA was detected by RT-PCR, flow cytometry and Hoechst-33258 were used to demonstrate apoptotic changes in celecoxib and cisplatin treated cells.

RESULTS: After treatment of BxPC-3 cells with celecoxib, as measured by MTT, cell viability was inhibited in a dose-dependent and time-dependent manner with an IC50 of 100 nM at the time of 24h. The expression of COX-2 mRNA could be significantly decreased by celecoxib. Furthermore, we demonstrated that the combination of celecoxib with cisplatin inhibited cell growth and induced cell apoptosis to a greater degree than either compound alone. The apoptotic morphologies were demonstrated by Hoechst-33 258.

CONCLUSION: Combination of celecoxib with cisplatin inhibits cell proliferation and induces cell apoptosis, and the potent effectiveness of celecoxib in combination with gemcitabine may hold a promise in the clinical treatment of pancreatic cancer.

Cyclooxygenase-2 expression in gastric mucosal cells with H. pylori infection and its relationship with apoptosis

AIM: To investigate the expression of Cox-2 in MKN28 and AGS gastric cells and gastric mucosal lesions with H. pylori infection, to determine whether Cox-2 gene expression by H. pylori infection could influence gastric cell apoptosis and to identify the relationship between Cox-2 and gastric carcinoma.

METHODS: The total H. pylori proteins of various concentrations were incubated with MKN28 and AGS gastric cells in vitro. RT-PCR and S-P immunohistochemical staining were used to detect the expression of Cox-2 before and after the incubation. 40 patients who underwent endoscopy were detected with S-P method. Apoptosis induced by H. pylori or selective Cox-2 inhibitor NS-398 or both was characterized by cell cycle kinetics with flow cytometry.

RESULTS: Expression of Cox-2 in MKN28 gastric mucosal cells incubated with H. pylori was significantly higher than that in non-incubated cells. Expression of Cox-2 protein in MKN28 gastric cells before and after incubated with H. pylori was 0.26 and 0.40 respectively (P<0.05), but in AGS gastric cells, the expression of Cox-2 protein was 0.29 and 0.31 before and after the incubation (P>0.05). Expression of Cox-2 protein in gastric carcinoma (GC) was higher than that in chronic superficial gastritis (CSG) and chronic atrophic gastritis (CAG) (P<0.05). The apoptosis rate when cells were incubated with H. pylori for 24h and 48h was 1.0% and 5.7% (P<0.05). Apoptofic cells were also observed after treated with 10, 100, 200 mol/L NS-398 for 24 h and 48 h, and apoptosis rate was 1.2%, 14.0% and 27.5%, and 1.5%, 31.4% and 51.8% respectively. However, the apopotosis induced by H. pylori and NS-398 was lower than that induced by NS-398 alone (P<0.01).

CONCLUSION: H. pylori upregulates Cox-2 expression in MKN28 gastric mucosal cells in vitro. Cox-2 can inhibit the apoptosis, which may promote gastric carcingenesis.

Effect of Chinese medicine Weikangning on expression of VEGF and its receptors Flt and KDR in gastric carcinoma cells

AIM: To study effect of traditional Chinese medicine Weikangning (WKN) on the expression of VEGF and its receptors Flt and KDR in gastric carcinoma cells.

METHODS: We used different dosage of WKN on rats to prepare serum containing WKN.The gastric carcinoma cells were cultured in the RPMI1640 media with serum containing WKN for 48 h. The expression of VEGF, Flt-1 and KDR was determined by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry in gastric cancer cell lines respectively.

RESULTS: All gastric cancer cell lines analyzed expressed VEGF Flt-1 and KDR. But the expression of fVEGF (186.82±0.22, 195.35±0.45, 172.62±0.52), Flt-1 (198.44±0.44, 188.66±0.46, 197.01±0.91) in cells cultured in serum containing WKN decreased in a dose-dependent manner as compared with control (VEGF162. 78±0.58, Flt: 172.65±0.65)(P < 0.05).

CONCLUSION: VEGF and its receptors KDR and Flt-1 are expressed widely in gastric carcinoma cells and WKN can inhibit their expression.

Potassium antimonyl tartrate induces apoptosis in human gastric carcinoma cells

AIM: Potassium antimonyl tartrate (PAT), an antiparasitic agent, has rencently been shown to induce apoptosis of leukaemia cells. Its effects on human gastric cancer SGC-7901 cells and possible mechanism were investigated in this study.

METHODS: The growth inhibition of cells induced by various concentrations of PAT in different time course was analyzed by using MTT assay. The nuclei were stained by Hoechst 33 258 and the morphologic changes were observed by fluorescence microscope. TUNEL staining, double-staining, and flow cytomery were used to detect apoptosis of cells.

RESULTS: Growth inhibitory rates of SGC-7901 cells by PAT were significantly different in dose-and time-dependent manners (analysis of variance, P < 0.01). Chromatin condensation and nuclear fragmentation were seen under fluorescence microscope in the cells treated with Hoechst 33 258, and apoptotic cells were also detected by flow cytometry and TUNEL staining.

CONCLUSION: PAT can induce the apoptosis of SGC-7901 cells, and PAT may be a promising apoptosis-inducer in gastric cancer therapy.

Relationship between expression of VEGF, Flt1, bFGF and P53and outcome in patients with gastric carcinoma

AIM: To investigate the relationship between the expression of VEGF, Flt1, bFGF and P⁵³, the clinicopathological characteristics and outcome in patients with gastric carcinoma.

METHODS: The relationship between VEGF, Flt1, bFGF, P⁵³ expression and clinicopathological characteristics and outcome in the patient was assessed by streptoavidin-biotin method of immunohistochemistry with polyclonal antibodies against VEGF, Flt1, bFGF, and P⁵³ protein. The survival curves were formulated using Kaplan-Meier method and analyzed by the log-rank test, and the influence of each variable on suvival was assessed by the Cox' s proportional hazard model.

RESULTS: VEGF expression was closely correlated with serosal invasion (Se, Sei invasion vs Pm, SS and M, SM invasion, P < 0.01). Expression of P⁵³ was obviously higher in the patients with lymph node metastasis than those without (lymph node metastasis vs non-lymph node metastasis, P < 0.05). There was a positive correlation between VEGF and Flt1 expression (VEGF expression in Flt1 positive group vs Flt1 negative group, P < 0.01). The factors that affected the prognosis in patients with gastric carcinoma were PTNM stage, VEGF expression, serosal invasion, and surgical curability. Flt1, bFGF, and P⁵³ expression had no influence on the prognosis of patients with gastric carcinoma (P > 0.05).

CONCLUSION: P⁵³ expression has significant relationship with lymph node metastasis in gastric carcinoma. VEGF expression is correlated with serosal invasion and the prognosis and may be a good prognostic indicator in gastric carcinoma.

Significance of COX-2 expression in human renal cell carcinoma cell lines

Accumulating evidences indicate that cyclooxygenase (COX)-2 plays an important role in tumorigenesis in many human cancers. Yet the relationship between COX-2 and human renal cell carcinoma (RCC) remains unclear. The aim of our study was to evaluate COX-2 expression in human RCC cell lines and its role in tumorigenesis of human RCC. Among the human RCC cell lines (SMKT-R4, OS-RC-2, ACHN) and normal renal cell line RPTEC, COX-2 overexpression was found in OS-RC-2 cells both at mRNA and protein levels. COX-2 sense- and antisense-orientated vectors were constructed and transferred into RCC cells. Significant suppression of cellular proliferation was demonstrated in OS-RC-2 antisense transfectants, whereas promotion was found in SMKT-R4 sense transfectants by colony-forming assay despite the observation that COX-2 specific inhibitor NS398 exhibited similar IC50 among RCC cell lines by MTT assay. In comparison with parent cells and sense transfectants, significant suppression of COX-2 expression and PGE2 production and increase in butyrate-induced apoptosis were observed in OS-RC-2 antisense transfectants by Western blot, ELISA assay and FACS analysis, respectively. Furthermore, tumor growth and angiogenesis of OS-RC-2 antisense transfectants in nude mice was significantly suppressed and the survival time of these mice was significantly prolonged. Our study demonstrates that COX-2 is overexpressed in OS-RC-2 RCC cell line and plays an important role in tumorigenesis of the cells in vivo, which implies that COX-2 may be a therapeutic target for COX-2-expressing RCC, and that suppression of COX-2 expression by antisense-based strategy may have potential utility in treatment of COX-2-expressing RCC.

Feasibility of VEGF ASODN mixed with lipiodol transfecting liver cancer via hepatic artery infusion in rats

AIM: To study the distribution and stability of VEGF ASODN in Walker-256 cells and to explore the distribution of VEGF ASODN in rat's liver, lung and kidney after mixed with lipiodol for hepatic artery infusion.

METHODS: The 5-FITC labeled VEGF ASODN was given into Walker-256 cell culture media. The cellular distribution was observed by fluorescent microscope. Walker-256 carcinosarcoma was transplanted into Wistar rat liver to establish the liver cancer model. 5'-FITC labeled VEGF ASODN mixed with (mixed group, n = 6) or without (TAI group, n = 6) ultra-fluide lipiodol was administrated via hepatic artery. The frozen samples of rats' liver, lung and kidney tissues were collected at 1, 3, and 6d after ASODN administration. The distribution of ASODN was determined under fluorescent microscope.

RESULTS: ASODN could enter the cytoplasm within 2 h and enter the nuclei within 4 h. Accumulation of the ASODN reached the high point in the nuclei at 6h. After that, they began to disappear. No fluorescence could be seen in cells at 48 h. At 1d and 3d, the fluorescence stained stronger in the liver in the mixed group than that in TAI group. More fluorescence could be detected in lung and kidney in TAI group than that in the mixed group. At 6 d, no fluorescence could be detected in TAI group tissues, but a little florescence could be seen in the mixed group tissues. ASODN could be seen in cancer cells and normal hepatic cells.

CONCLUSION: VEGF ASODN can transfect Walker-256 cells. VEGF ASODN stays longer in the liver, is transfected more into hepatic and cancerous cells and distributes less in other tissue when mixed with lipiodol. VEGF ASODN mixed with lipiodol via hepatic artery is an ideal way treating liver carcinoma.