Up-regulation of cyclooxygenase 2 gene expression correlates with tumor angiogenesis in human colorectal cancer.

BACKGROUND & AIMS: Recent studies have shown that cyclooxygenase (COX)-2 and its products, prostaglandins (PGs), may be involved in colorectal carcinogenesis. The aim of this study was to determine whether COX-2 expression and PGE(2) production correlate with microvessel density, vascular endothelial growth factor (VEGF) expression, and tumor metastasis in human colorectal cancer. METHODS: Tumor samples and adjacent normal mucosa were obtained from 31 surgical specimens. Immunohistochemical expression of COX-2, VEGF, and CD31 was analyzed on paraffin-embedded tissue sections. COX-2 and COX-1 proteins were determined by Western blot analysis. COX-2 and VEGF messenger RNA expressions were evaluated using Northern blot analysis. PGE(2) production was determined by specific radioimmunoassay. RESULTS: The immunohistochemical expressions of both COX-2 and VEGF were significantly correlated with microvessel density (P = 0.02 and P = 0.002, respectively). A significant correlation was found between COX-2 and VEGF expression (P = 0.004). Western analysis confirmed the up-regulation of COX-2 protein expression. COX-2 and VEGF genes were overexpressed in tumor specimens as compared with normal mucosa. PGE(2) levels were significantly higher in metastatic tumors than in nonmetastatic ones (P = 0.03). CONCLUSIONS: COX-2 is related to tumor angiogenesis in colorectal cancer. It is likely that VEGF is one of the most important mediators of the COX-2 angiogenic pathway.     

Cyclooxygenase-2 expression as a predictor of outcome in colorectal carcinoma

AIM: To correlate cyclooxygenase-2 (COX-2) expression profile with clinical and pathological variables to assess their prognostic/predictive value in colorectal carcinoma (CRC).METHODS: Archival tumor samples were analyzed using immunohistochemistry for COX-2 expression in 94 patients with CRC. Patients were diagnosed and treated at the Departments of Surgery and Oncology, King Abdulaziz University Hospital, Saudi Arabia.RESULTS: Fifty-six percent of the tumors showed positive cytoplasmic COX-2 expression, whereas 44% of cases were completely COX-2-negative. There were no significant correlations between COX-2 expression and sex, age, grade or tumor location. However, COX-2 expression revealed a significant correlation with tumor stage (P = 0.01) and distant metastasis (P = 0.02), and a borderline association with lymph node involvement (P = 0.07). Tumors with high COX-2 expression showed a higher recurrence rate than tumors with no expression (P < 0.009). In univariate Kaplan-Meier survival analysis, there was a significant (P = 0.026) difference in disease-free survival between COX-2-positive and negative tumors in favor of the latter. COX-2 expression did not significantly predict disease-specific survival, which was much shorter for COX-2-positive tumors. In multivariate (COX) models, COX-2 did not appear among the independent predictors of disease-free survival or disease-specific survival.CONCLUSION: COX-2 expression seems to provide useful prognostic information in CRC, while predicting the patients at high risk for recurrent disease.     

COX-2 inhibition as a tool to treat and prevent colorectal cancer

The cyclooxygenase-2 (COX-2) enzyme has a fundamental role in the carcinogenesis of colorectal cancer. The anticarcinogenic mechanisms of NSAIDs are not completely understood and appear to be only partially dependent on inhibition tumoral COX-2. Moreover, the mechanisms of NSAIDs depend on the concentration. In experimental setting, at low levels NSAIDs downregulate the COX-2 gene in colorectal cancer cells, whereas at clinical relevant concentrations the production of prostaglandin E2 by enzymatic activity of COX-2 is diminished resulting in inhibition of the tumor angiogenesis. At higher levels NSAIDs and especially some selective COX-2 inhibitors are capable of COX-2 independent effects, such as apoptosis induction of tumor cells. In animal models, NSAIDs administration results in inhibition of angiogenesis and proliferation, induction apoptosis and prevention of metastasis. In clinical setting, NSAIDs and selective COX-2 inhibitors have the capacity to prevent the development of colorectal adenomas. We have summarized data regarding the role of COX-2 in CRC and discuss the multiple targets of NSAIDs in their anticarcinogenic action. However, the translation of these anticarcinogenic effects of NSAIDs to its clinical application as adjuvant therapy in CRC is hampered by a lack of randomized clinical trials with long-term follow-up.     

Differential expression of cyclooxygenase 2 in human colorectal cancer

BACKGROUND: Experimental, clinical, and epidemiological studies have implicated mitogenic metabolites of arachidonic acid such as prostaglandin E(2) (PGE(2)) in colorectal carcinogenesis. Recently, cyclooxygenase 2 (COX-2) which catalyses the conversion of arachidonic acid to PGE(2), has displayed increased levels in human colorectal cancer. AIMS: To evaluate whether there is differential COX-2 expression from different locations (caecum, ascending, transverse, descending, or sigmoid colon, and rectum) in human colorectal cancer. METHODS: Protein levels of COX-2 were determined by western blot analysis in tumours and adjacent normal mucosa of 39 patients with colorectal cancer. RESULTS: There was a notable overexpression of COX-2 protein in tumours located in the rectum (p<0.001) compared with other locations in the colon. Rectal tumours revealed elevated COX-2 protein levels in 18/20 cases compared with 4/19 colonic cases. No association between enhanced COX-2 protein expression in tumour tissue and Dukes's stages was found. CONCLUSIONS: Results suggest that the differential COX-2 expression may be due to differences in gene regulatory factors affecting COX-2 expression and/or reflect secondary changes in tumour progression which may have clinical implications.     

The endogenous cannabinoid, anandamide, induces cell death in colorectal carcinoma cells: a possible role for cyclooxygenase 2

BACKGROUND AND AIMS: Cyclooxygenase 2 (COX-2) is upregulated in most colorectal cancers and is responsible for metabolism of the endogenous cannabinoid, anandamide, into prostaglandin-ethanolamides (PG-EAs). The aims of this study were to determine whether anandamide and PG-EAs induce cell death in colorectal carcinoma (CRC) cells, and whether high levels of COX-2 in CRC cells could be utilised for their specific targeting for cell death by anandamide. METHODS: We determined the effect of anandamide on human CRC cell growth by measuring cell growth and cell death, whether this was dependent on COX-2 protein expression or enzyme activity, and the potential involvement of PG-EAs in induction of cell death. RESULTS: Anandamide inhibited the growth of CRC cell lines HT29 and HCA7/C29 (moderate and high COX-2 expressors, respectively) but had little effect on the very low COX-2 expressing CRC cell line, SW480. Induction of cell death in HT29 and HCA7/C29 cell lines was partially rescued by the COX-2 selective inhibitor NS398. Cell death induced by anandamide was neither apoptosis nor necrosis. Furthermore, inhibition of fatty acid amide hydrolase potentiated the non-apoptotic cell death, indicating that anandamide induced cell death was mediated via metabolism of anandamide by COX-2, rather than its degradation into arachidonic acid and ethanolamine. Interestingly, both PGE2-EA and PGD2-EA induced classical apoptosis. CONCLUSIONS: These findings suggest anandamide may be a useful chemopreventive/therapeutic agent for colorectal cancer as it targets cells that are high expressors of COX-2, and may also be used in the eradication of tumour cells that have become resistant to apoptosis.     

Progastrin and cyclooxygenase-2 in colorectal cancer

Colorectal cancers (CRCs) are one of the most common forms of cancer in Poland and one of the leading causes of death. The tumors have been attributed to genetic, dietary, and other environmental factors, but recently growth factors such as gastrin have also been implicated in the carcinogenesis. The relationship between plasma amidated and nonamidated gastrin in CRCs is controversial. This study was designed (1) to determine the plasma levels of progastrin and amidated gastrin in 50 CRC patients before and 3–6 months after removal of the tumor, (2) to determine the tumor concentrations of these gastrin peptides and the level of expression for gastrin mRNA and gastrin/CCK_B receptor mRNA, (3) to examine the expression of cyclooxygenase COX-1 and COX-2 mRNA in CRC tissue, and (4) to compare the prevalence of Hp and its cytotoxic protein, CagA, and cytokines (TNF, IL-1, and IL-8) in CRCs, before and after removal of tumor. It was found that the CRC, its resection margin, and the plasma contained severalfold higher levels of progastrin than of amidated gastrins and that the removal of the CRC tumor resulted in a marked reduction in plasma progastrin level without a significant alteration in plasma levels of amidated gastrins. Both gastrin and CCK_B-R mRNA were detected in the cancer tissue and resection margin by RT-PCR, and similarly, COX-1 and COX-2 mRNA were expressed in these tissues of most CRCs. The seroprevalence of Hp, especially that expressing CagA, and levels of IL-1, but not other cytokines, were significantly higher in CRC patients than in 100 age-, gender-, and profession-matched controls and did not change significantly about 3–6 months after tumor resection. We conclude that (1) the CRC and its margin contain large amounts of progastrin and show gene expression of gastrin, CCK_B-R, and COX-2; (2) removal of the CRC markedly reduces the plasma concentrations of progastrin; (3) the Hp infection rate is higher in CRC, and this may contribute to colorectal cancerogenesis via enhancement of progastrin and gastrin release; and (4) plasma progastrin concentrations might serve as a biomarker of CRC.     

Effects of Cyclooxygenase-2 Inhibition on Serum and Tumor Gastrins and Expression of Apoptosis-Related Proteins in Colorectal Cancer

The objective of the present study was to determine the influence of cyclooxygenase-2 (COX-2) inhibition by Celecoxib (CLX) in humans with distal colorectal adenocarcinoma (CRC) on serum and tumor levels of progastrin and gastrin and serum levels of proinflammatory cytokines (IL-8, TNF-α). In addition, the effects of this CLX treatment on tumor and adjacent mucosa expression of gastrin, its receptors (CCK₂), and COX-1 and COX-2, as well as protein expression of the active form of nuclear factor κ B (NFκ B) and the apoptotic-related proteins Bcl-2 and survivin, have been examined. Ten distal CRC patients were examined twice, once before and then after 14-day treatment with CLX (200 mg bid). Large biopsy samples were taken from the tumor and intact mucosa 10 cm above the tumor. For comparison, 20 age- and sex-matched healthy controls were enrolled and treated with CLX as CRC patients. Serum levels of IL-8 and TNF-α were measured by enzyme-linked immunosorbent assay, and serum levels of amidated gastrins and progastrin, by specific radioimmunoassay. The gene or protein expressions of progastrin, gastrin, CCK₂, COX-1, COX-2, Bcl-2, and survivin as well as NFκ B were determined by RT-PCR or Western blot in biopsy samples of tumor and intact mucosa of CRC patients. Serum IL-8 and TNF-α values were severalfold higher in CRC patients than in controls. The increase in serum proinflammatory cytokines was accompanied by increased expression of the active form of NFκ B. Serum progastrin levels were also found to be significantly higher in CRC than in controls. Treatment of CRC with CLX resulted in a significant decrease in serum levels of progastrin and this was accompanied by an increment in tumor expression of COX-2 with a concomitant reduction in gastrin, Bcl-2, survivin, and NFκ B expression. We conclude that (1) distal CRC patients show significantly higher serum progastrin levels than matched healthy controls, confirming that this hormone may be implicated in rectal carcinogenesis; (2) CRC patients exhibit significantly higher serum levels of IL-8 and TNF-α than healthy controls, probably reflecting more widespread inflammatory reaction in the colonic mucosa in CRC; (3) gastrin, COX-2, Bcl-2, survivin, and NFκ B were overexpressed in CRC tumor compared to intact mucosa, but treatment with CLX significantly reduced serum levels of progastrin and IL-8 and TNF-α, which could mediate the up-regulation of COX-2 in CRC; and (4) CLX also enhanced expression of COX-2, while inhibiting the expression of gastrin, Bcl-2, survivin, and NFκ B, suggesting that COX-2 inhibition might be useful in chemoprevention against CRC, possibly due to suppression of the antiapoptotic proteins and reduction in progastrin-induced and NFκ B-promoted tumor growth.     

The role of NSAIDs in colon cancer prevention

Experiments in animals and population-based studies have shown the efficacy of nonsteroidal antiinflammatory drugs in colorectal cancer prevention. COX-2 is overexpressed in dysplastic and neoplastic epithelium. COX-2 is a key-enzyme in several tumorigenic pathways, such as promotion of tumor angiogenesis. Non-selective inhibition of COX enzyme demonstrates a protective effect as well, suggesting that more than one mechanism takes place in neoplastic transformation. Blockade of COX enzyme by NSAIDs down-regulates its metabolic product prostaglandin E2. Inhibition of PGE2 seems to have a negative effect in cancer occurrence. Induction of apoptosis is another mechanism that explains the protective effect of NSAIDs. The recently discovered PPARdelta factor, is also overexpressed in neoplastic tissue, and may be a mediator through which COX-2 exerts its oncogenic effect.     

Special AT-rich sequence-binding protein 1 promotes cell growth and metastasis in colorectal cancer

AIM: To evaluate the expression of special AT-rich sequence-binding protein 1 (SATB1 ) gene in colorectal cancer and its role in colorectal cancer cell proliferation and invasion.METHODS: Immunohistochemistry was used to detect the protein expression of SATB1 in 30 colorectal cancer (CRC) tissue samples and pair-matched adjacent nontumor samples. Cell growth was investigated after enhancing expression of SATB1. Wound-healing assay and Transwell assay were used to investigate the impact of SATB1 on migratory and invasive abilities of SW480 cells in vitro . Nude mice that received subcutaneous implantation or lateral tail vein were used to study the effects of SATB1 on tumor growth or metastasis in vivo . RESULTS: SATB1 was over-expressed in CRC tissues and CRC cell lines. SATB1 promotes cell proliferation and cell cycle progression in CRC SW480 cells. SATB1 over-expression could promote cell growth in vivo . In addition, SATB1 could significantly raise the ability of cell migration and invasion in vitro and promote the ability of tumor metastasis in vivo . SATB1 could up-regulate matrix metalloproteases 2, 9, cyclin D1 and vimentin, meanwhile SATB1 could down-regulate E-cadherin in CRC. CONCLUSION: SATB1 acts as a potential growth and metastasis promoter in CRC. SATB1 may be useful as a therapeutic target for CRC.     

Overexpression of cyclooxygenase-2 correlates with advanced stages of colorectal cancer

OBJECTIVE: We aimed to investigate the associations of cyclooxygenase-2 (COX-2) with pathological features and survival in patients with colorectal cancer. METHODS: The expression of COX-2 was examined by immunohistochemistry in 112 primary colorectal cancers, with 64 samples from the corresponding normal mucosa and 16 metastases in the regional lymph nodes of patients with colorectal cancer. The associations of COX-2 expression with clinicopathological features, including survival, were analyzed. RESULTS: The frequency and intensity of COX-2 staining were remarkably increased from the normal samples (17%) to the primary tumors (72%) and to the metastases (100%). Expressions of COX-2 were 25%, 74%, 78%, and 67% in Dukes' A, B, C, and D tumors, respectively (p = 0.005), and positively related to proliferative activity (p = 0.003). COX-2 expressions were 80% in colonic tumors and 60% in rectal tumors (p = 0.03). The expression of COX-2 was positively related to the better differentiated tumors in the colon (p = 0.04). We were unable to find any relationship of COX-2 with patient age, sex, tumor growth pattern, apoptosis, and patient survival (p > 0.05). CONCLUSION: We found that the expression of COX-2 was upregulated from normal cells to primary tumors and to metastases, and related to proliferative activity, tumor location, Dukes' stage, and differentiation. These results further support the evidence that COX-2 may be involved in tumorigenesis and development of colorectal cancer.     

Adiponectin receptor expression is elevated in colorectal carcinomas but not in gastrointestinal stromal tumors

Circulating adiponectin is inversely associated with colorectal carcinoma. However, adiponectin receptor expression has not been examined in normal gastrointestinal tissue, colorectal malignancies, or gastrointestinal stromal tumors (GISTs). We collected 40 colorectal carcinomas and 12 non-tumor colorectal tissue specimens from patients with colorectal cancer, as well as 45 tumor and 13 non-tumor specimens from patients with GIST. Expression and localization of adiponectin receptors (AdipoR1 and AdipoR2) were assessed using immunohistochemistry. We also confirmed expression of adiponectin receptors using rtPCR in matched normal and colorectal cancer specimens obtained from five patients. Finally, we detected adiponectin receptors and assessed adiponectin signaling in three colon cancer cell lines. Adiponectin receptor expression, assessed by either rtPCR or immunohistochemistry, was present in normal tissue and was significantly lower than in colorectal carcinomas. Among carcinomas, 95% displayed positive or strongly positive expression of AdipoR1 and 88% of AdipoR2, versus 8% and 0%, respectively, for non-tumor specimens (P<0.0001). AdipoR1 expression assessed by rtPCR was 1.6-fold higher in tumor than in non-tumor tissue (P<0.05). In addition, we found that adiponectin at physiological concentrations can activate in vitro intracellular signaling pathways in three colon cancer cell lines, expressing both adiponectin receptors 1 and 2. No significant differences in expression of adiponectin receptors in tumor versus non-tumor GI specimens were detected among patients with GIST. Colon cancer cell lines express adiponectin receptors, through which adiponectin activates in vitro intracellular signaling pathways. Adiponectin receptors are also detected in normal GI tissue and their expression is elevated in colorectal carcinomas, but not in GIST.     

Identification and functional characterization of paxillin as a target of protein tyrosine phosphatase receptor T

Protein tyrosine phosphatase receptor-type T (PTPRT) is the most frequently mutated tyrosine phosphatase in human cancers. However, the cell signaling pathways regulated by PTPRT largely remain to be elucidated. Here, we show that paxillin is a direct substrate of PTPRT and that PTPRT specifically regulates paxillin phosphorylation at tyrosine residue 88 (Y88) in colorectal cancer (CRC) cells. We engineered CRC cells homozygous for a paxillin Y88F knock-in mutant and found that these cells exhibit significantly reduced cell migration and impaired anchorage-independent growth, fail to form xenograft tumors in nude mice, and have decreased phosphorylation of p130CAS, SHP2, and AKT. PTPRT knockout mice that we generated exhibit increased levels of colonic paxillin phosphorylation at residue Y88 and are highly susceptible to carcinogen azoxymethane-induced colon tumor, providing critical in vivo evidence that PTPRT normally functions as a tumor suppressor. Moreover, similarly increased paxillin pY88 is also found as a common feature of human colon cancers. These studies reveal an important signaling pathway that plays a critical role in colorectal tumorigenesis.     

Osteonecrosis of the jaw in a Crohn’s disease patient following a course of Bisphosphonate and Adalimumab therapy: a case report

Background

Cyclooxygenase-2 (COX-2, PTGS2) is an enzyme involved in the synthesis of prostaglandins and thromboxanes, which are regulators of biologic processes such as inflammation, cell proliferation and angiogenesis. COX-2 over-expression was reported in many (pre) malignant tissues, but data strongly vary and seem to depend on the methodology used.

Methods

Normal colorectal mucosa and paired cancerous tissue from 60 patients with colorectal cancer was investigated for the levels of COX-2 mRNA by real-time quantitative Polymerase Chain Reaction (qPCR). COX-2 levels were expressed relative to either: tissue weight or levels of the housekeeping genes beta-2 microglobulin (B2M) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH).

Results

COX-2 mRNA levels, normalized with respect to tissue weight or mRNA levels of the housekeeping genes B2M or GAPDH, were over-expressed in 80%, 70% and 40% of the colorectal tumor tissues, as compared to the paired adjacent normal colorectal mucosa samples, respectively. Highest mRNA COX-2 ratios tumor/normal were measured when expressed per mg tissue (mean ratio 21.6). When normalized with respect to the housekeeping genes B2M or GAPDH, mean tumor/normal ratios were 16.1 and 7.5, respectively.

Conclusion

Expression of COX-2 mRNA levels per mg tissue is most simple in comparison to normalization with respect to the housekeeping genes B2M or GAPDH. Levels of COX-2 mRNA are found over-expressed in almost 80% of the colorectal tumors, compared to paired adjacent normal colorectal mucosa, suggesting a role of COX-2 as a potential biomarker for cancer risk, whereas inhibitors of COX-2 could be of value in chemoprevention of colon cancer.     

Clinical significance of human kallikrein 10 gene expression in colorectal cancer and gastric cancer

BACKGROUND AND AIM: Recent evidence suggests that the human kallikrein 10 (KLK10) gene is differentially regulated in endocrine-related tumors and has potential as diagnostic and/or prognostic marker; however, KLK10 expression has never been investigated in gastrointestinal cancers. The aims of this study were to demonstrate expression and single nucleotide polymorphisms of KLK10 in colorectal cancer (CRC) and gastric cancer (GC), and to correlate the relative KLK10 expression level with clinicopathological factors of CRC and GC. METHODS: Between March 2004 and January 2005, 63 patients with histologically confirmed CRC and 36 with GC were recruited into the study. Using quantitative real-time (qRT) RT-PCR and Western blot, KLK10 expression in tumor and non-tumor colorectal and gastric tissues was determined at the mRNA and protein levels. KLK10 protein was localized by immunohistochemistry. The KLK10 genomic DNA from 16 cases of paired normal/cancerous colorectal tissues was PCR-amplified and examined for single nucleotide polymorphisms by direct sequencing. RESULTS: KLK10 mRNA expression was detected by qRT in 61 of 63 (96.8%) CRC specimens and in all GC specimens. KLK10 expression was much higher in tumor tissue than in the corresponding normal mucosal tissue at the mRNA and protein levels (P<0.01). The KLK10 mRNA expression level significantly correlated with lymphatic invasion (P=0.034) and clinical stage of CRC (P=0.025). The KLK10 mRNA expression level significantly correlated with the depth of GC invasion (P=0.018), clinical stage (P=0.045), patient sex (P=0.027) and Lauren type of gastric cancer (P=0.028). No mutations or polymorphisms were detected in exon 1, 2 and 5 of KLK10 gene in CRC. Single nucleotide polymorphisms were identified in codon 50 of exon 3, GCC (alanine) to TCC (serine). The genetic changes of exon 4 were located at codon 106 [GGC (glysine) to GGA (glysine)], codon 112 [ACG (threonine) to ACC (threonine)], codon 141 [CTA (leucine) to CTG (leucine)], and codon 149 [CCG (proline) to CTG (leucine)]. All were identical in tumor and corresponding normal tissue DNA from the same individuals. CONCLUSION: KLK10 expression is up-regulated in CRC and GC and higher expression of KLK10 closely correlates with advanced disease stage, which predicts a poorer prognosis; however, further follow-up study is needed.     

Adiponectin deficiency enhances colorectal carcinogenesis and liver tumor formation induced by azoxymethane in mice

AIM： To investigate the causal relationship between hypoadiponectinemia and colorectal carcinogenesis in in vivo experimental model, and to determine the contribution of adiponectin deficiency to colorectal cancer development and proliferation. METHODS： We examined the influence of adiponectin deficiency on colorectal carcinogenesis induced by the administration of azoxymethane （AOM） （7.5 mg/kg, intraperitoneal injection once a week for 8 wk）, by using adiponectin-knockout （KO） mice. RESULTS： At 53 wk after the first AOM treatment, KOmice developed larger and histologically more progressive colorectal tumors with greater frequency compared with wild-type （WT） mice, although the tumor incidence was not different between WT and KO mice. KO mice showed increased cell proliferation of colorectal tumor cells, which correlated with the expression levels of cyclooxygenase-2 （COX-2） in the colorectal tumors. In addition, KO mice showed higher incidence and frequency of liver tumors after AOM treatment. Thirteen percent of WT mice developed liver tumors, and these WT mice had only a single tumor. In contrast, 50% of KO mice developed liver tumors, and 58% of these KO mice had multiple tumors. CONCLUSION： Adiponectin deficiency enhances colorectal carcinogenesis and liver tumor formation induced by AOM in mice. This study strongly suggests that hypoadiponectinemia could be involved in the pathogenesis for colorectal cancer and liver tumor in human subjects.