Cyclooxygenase-2 In Colorectal Cancer Research Articles

Repurposing [11C]MC1 for PET Imaging of Cyclooxygenase-2 in Colorectal Cancer Xenograft Mouse Models.

Cyclooxygenase-2 (COX-2) is a target for inflammation and colorectal cancer (CRC). This study evaluated the COX-2 neuro-PET radiopharmaceutical, [11C]MC1, in CRC xenograft mice. [11C]MC1 was evaluated in ICRscid mice with HT-29 and HCT-116 CRC xenografts, with high and low COX-2 expression, respectively, by immunohistochemistry, cellular uptake, dynamic PET/MR imaging, ex vivo biodistribution, and radiometabolite analysis. HT-29 xenografts were well visualized with [11C]MC1 using PET/MR. Time-activity curves revealed steady tumor radioactivity accumulation in HT-29 xenografts that plateaued from 40 to 60 min (3.07 ± 0.65 %ID/g) and was significantly reduced by pre-treatment with MC1 or celecoxib (1.62 ± 0.29 and 1.18 ± 0.21 %ID/g, respectively, p = 0.045 and p = 0.005). Radiometabolite analysis showed that [11C]MC1 accounted for >90 % of tumor radioactivity, with <10 % in plasma, at 40 min post-injection of the radiotracer. [11C]MC1 is a promising PET imaging agent for COX-2 in CRC and translation for cancer research should be considered.

The Role of Cyclooxygenase-2 in Colorectal Cancer.

Colorectal cancer is the third common cancer in this world, accounting for more than 1 million cases each year. However, detailed etiology and mechanism of colorectal cancer have not been fully understood. For example, cyclooxygenase-2 (COX-2) and its product prostaglandin E2 (PGE2) have been closely linked to its occurrence, progression and prognosis. However, the mechanisms on how COX-2 and PGE2-mediate the pathogenesis of colorectal cancer are obscure. In this review, we have summarized recent advances in studies of pathogenesis and control in colorectal cancer to assist further advances in the research for the cure of the cancer. In addition, the knowledge gained may also guide the audiences for reduction of the risk and control of this deadly disease.

Immunohistochemical expression of Cyclooxygenase-2 in colorectal carcinoma and its association with clinicopathological parameters

Background and objective: Inflammatory process and genetic factors play a key role in neoplasia of colorectal cancer. Cyclooxygenase-2 is involved in a variety of important cellular functions, including cell growth and differentiation, cancer cell motility and invasion, angiogenesis, and immune functions. This study aimed to evaluate the frequency of cyclooxygenase-2 in colorectal cancer and its correlations with different clinicopathological parameters. Methods: A study carried out in the Department of Pathology in Rizgary Teaching Hospital and private laboratories in Erbil city from May 2015 to February 2016. Eighty formalin-fixed paraffin-embedded specimens of colorectal cancers were collected. The clinicopathological data was collected by the researcher from records of known cases of colorectal carcinoma in Erbil city and was done in a private laboratory in Dohuk city. Results: High cyclooxygenase-2 expression was represented by 63.8% of colorectal carcinoma patients, and low expression was represented by 36.2% of them. There was a significant association between the mucinous subtype of colorectal carcinoma and low cyclooxygenase-2 expression (P = 0.01). A significant association was observed between moderately differentiated carcinoma and high cyclooxygenase-2 expression (P = 0.04). A significant association was also noted between increased tumor size and high cyclooxygenase-2 expression (P = 0.03). Conclusion: Cyclooxygenase-2 expression is more likely to be prevalent among colorectal carcinoma patients and is correlated to tumor subtypes (low in mucinous subtypes), grade (high in moderately differentiated), and tumor size (high in the big sized tumor).

Expression and association of carbonic anhydrase IX and cyclooxygenase-2 in colorectal cancer

BackgroundThis work was designed to determine the relationship between hypoxia-inducible protein carbonic anhydrase IX (CA IX) and pro-inflammatory enzyme cyclooxygenase-2 (COX-2) in patients with colorectal cancer (CRC). MethodsWe examined CA IX and COX-2 expression in CRC tissues by immunohistochemical staining of 111 samples. We evaluated the correlation between the expression of these proteins and their correlation with the clinico-morphological parameters of CRC. ResultsCA IX was detected in 89 of 111 cases (80.2%). We predominantly observed membrane staining (70.3%) and a strong immunoreaction intensity (58.6%). The percentage of labeled cells in malignant lesions was less than 25% in 12.6% of cases, less than 50% in 15.3% of cases and more than 50% in 52.3% of CRC cases. The COX-2 protein was expressed in 94 of 111 cases (84.7%). We noticed only cytoplasmic localization, while immunoreaction intensity was predominantly strong (47.8%). The percentage of COX-2 positive cells was less than 25% only in 2.7% of the cases, less than 50% in 21.6% of the cases and more than 50% in 60.4% of the cases. No statistically significant correlations were observed between CA IX expression and clinico-morphological parameters. COX-2 expression was only significantly correlated with the tumor stage. Statistical analysis confirmed a significant correlation between the parameters of expression of the CA IX and COX-2 proteins. ConclusionCA IX/COX-2 interplay can promote hypoxia survival and the invasion of tumor cells. These proteins may represent independent prognostic factors of CRC.

Correlations of IGF-1R and COX-2 Expressions with Ras and BRAF Genetic Mutations, Clinicopathological Features and Prognosis of Colorectal Cancer Patients.

This case-control study aims to investigate the correlations of insulin-like growth factor receptor 1 (IGF-1R) and cyclooxygenase 2 (COX-2) expressions with Ras and BRAF genetic mutations, clinicopathological features and prognosis of colorectal cancer (CRC) patients. A total of 213 CRC patients (case group) and 200 healthy individuals (control group) were selected from our hospital. Ras (K-Ras/N-Ras) and BRAF genetic mutations were detected by direct sequencing. The positive expression rates of IGF-IR and COX-2 in CRC and normal tissues were detected using immunohistochemistry. RT-qPCR and Western blotting were applied to detect the mRNA and protein expressions of IGF-IR and COX-2 in CRC tissues and normal tissues. Total mutation rate of N-Ras, BRAF and K-Ras in case group were 5.2%, 12.2% and 47.4%, respectively. The expressions of IGF-IR and COX-2 were higher in CRC tissues with Ras and BRAF mutations than in those without. CRC tissues with Ras mutation showed higher COX-2 expression than those with BRAF mutation. IGF-IR and COX-2 expressions were correlated to infiltration degree, lymphatic metastasis (in CRC tissues with and without Ras and BRAF mutations), and Dukes stages (only in CRC tissues with Ras and BRAF mutations). CRC patients with negative expressions of IGF-IR and COX-2 had significantly higher accumulative survival rate and longer mean survival duration than those with positive expressions of IGF-IR and COX-2. These findings indicate that IGF-1R and COX-2 expressions may be associated with Ras and BRAF genetic mutations, clinicopathological feature and prognosis of CRC patients.

PET imaging of cyclooxygenase-2 (COX-2) in a pre-clinical colorectal cancer model.

BackgroundCyclooxygenase-2 (COX-2) is the inducible isoform of the cyclooxygenase enzyme family. COX-2 is involved in tumor development and progression, and frequent overexpression of COX-2 in a variety of human cancers has made COX-2 an important drug target for cancer treatment. Non-invasive imaging of COX-2 expression in cancer would be useful for assessing COX-2-mediated effects on chemoprevention and radiosensitization using COX-2 inhibitors as an emerging class of anti-cancer drugs, especially for colorectal cancer. Herein, we describe the radiopharmacological analysis of [18F]Pyricoxib, a novel radiolabeled COX-2 inhibitor, for specific PET imaging of COX-2 in colorectal cancer.MethodsUptake of [18F]Pyricoxib was assessed in human colorectal cancer cell lines HCA-7 (COX-2 positive) and HCT-116 (COX-2 negative). Standard COX-2 inhibitors were used to test for specificity of [18F]Pyricoxib for COX-2 binding in vitro and in vivo. PET imaging, biodistribution, and radiometabolite analyses were included into radiopharmacological evaluation of [18F]Pyricoxib.ResultsRadiotracer uptake in COX-2 positive HCA-7 cells was significantly higher than in COX-2 negative HCT-116 cells (P < 0.05). COX-2 inhibitors, celecoxib, rofecoxib, and SC58125, blocked uptake of [18F]Pyricoxib in HCA-7 cells in a concentration-dependent manner. The radiotracer was slowly metabolized in mice, with approximately 60 % of intact compound after 2 h post-injection. Selective COX-2-mediated tumor uptake of [18F]Pyricoxib in HCA-7 xenografts was confirmed in vivo. Celecoxib (100 mg/kg) selectively blocked tumor uptake by 16 % (PET image analysis; P < 0.05) and by 51 % (biodistribution studies; P < 0.01).ConclusionsThe novel PET radiotracer [18F]Pyricoxib displays a promising radiopharmacological profile to study COX-2 expression in cancer in vivo.Electronic supplementary materialThe online version of this article (doi:10.1186/s13550-016-0192-9) contains supplementary material, which is available to authorized users.

The role of COX-2 in intestinal inflammation and colorectal cancer

Colorectal cancer (CRC) is a heterogeneous disease, including at least three major forms: hereditary, sporadic and colitis-associated CRC. A large body of evidence indicates that genetic mutations, epigenetic changes, chronic inflammation, diet and lifestyle are the risk factors for CRC. As elevated cyclooxygenase-2 (COX-2) expression was found in most CRC tissue and is associated with worse survival among CRC patients, investigators have sought to evaluate the effects of nonsteroidal anti-inflammatory drugs (NSAIDs) and selective COX-2 inhibitors (COXIBs) on CRC. The epidemiological studies, clinical trials and animal experiments indicate that NSAIDs are among the most promising chemopreventive agents for this disease. NSAIDs exert their anti-inflammatory and antitumor effects primarily by reducing prostaglandin production by inhibition of COX-2 activity. In this review, we highlight breakthroughs in our understanding of the roles of COX-2 in CRC and inflammatory bowel disease. These recent data provide a rationale for re-evaluating COX-2 as both the prognostic and the predictive marker in a wide variety of malignancies and for renewing the interest in evaluating relative benefits and risk of COXIBs in appropriately selected patients for cancer prevention and treatment.

Regulation of the apoptosis-inducing kinase DRAK2 by cyclooxygenase-2 in colorectal cancer

Background:Cyclooxygenase-2 (COX-2) is over-expressed in colorectal cancer (CRC), rendering tumour cells resistant to apoptosis. Selective COX-2 inhibition is effective in CRC prevention, although having adverse cardiovascular effects, thus focus has shifted to downstream pathways.Methods:Microarray experiments identified genes regulated by COX-2 in HCA7 CRC cells. In vitro and in vivo regulation of DRAK2 (DAP kinase-related apoptosis-inducing kinase 2 or STK17β, an apoptosis-inducing kinase) by COX-2 was validated by qRT-PCR.Results:Inhibition of COX-2 induced apoptosis and enhanced DRAK2 expression in HCA7 cells (4.4-fold increase at 4 h by qRT-PCR, P=0.001), an effect prevented by co-administration of PGE2. DRAK2 levels were suppressed in a panel of human colorectal tumours (n=10) compared to normal mucosa, and showed inverse correlation with COX-2 expression (R=−0.68, R2=0.46, P=0.03). Administration of the selective COX-2 inhibitor rofecoxib to patients with CRC (n=5) induced DRAK2 expression in tumours (2.5-fold increase, P=0.01). In vitro silencing of DRAK2 by RNAi enhanced CRC cell survival following COX-2 inhibitor treatment.Conclusion:DRAK2 is a serine–threonine kinase implicated in the regulation of apoptosis and is negatively regulated by COX-2 in vitro and in vivo, suggesting a novel mechanism for the effect of COX-2 on cancer cell survival.

Regulation of cell cycle progression by cyclooxygenase-2 in colorectal cancer; the role of the EP4 receptor, a novel therapeutic target

Aims: Cyclooxygenase-2 (COX-2) expression is elevated in colorectal cancer (CRC) and is associated with poor survival for reasons which are not well characterised. We assessed the mechanisms by which COX-2 might regulate cell cycle progression in a colon cancer cell line.

Expression of cyclooxygenase-2 in colorectal cancer and its clinical significance

To clarify the clinicopathologic significance of COX-2 expression in human colorectal cancer. A total of 128 surgically resected colorectal cancer specimens were immunohistochemically analyzed with the use of anti-COX-2, anti-VEGF and anti-MMP-2 antibodies. The relationship between the cyclooxygenase-2 expression in primary lesions of colorectal cancer and clinicopathologic parameters was evaluated by chi-square test. Among 128 cases of colorectal cancer, 87 (67.9%) were positive for cyclooxygenase-2. The expression of cyclooxygenase-2 was significantly correlated with the depth of invasion, stage of disease, and metastasis (lymph node and liver). Patients in T3-T4, stages III-IV and with metastasis had much higher expression of cyclooxygenase-2 than ones in T1-T2, stages I-II and without metastasis (P<0.05). Among 45 cases of colorectal cancer with lymph node metastasis, the COX-2- positive rate was 86.7% (39/45) for primary lesions and diffuse cytoplasmic staining for COX-2 protein was detected in cancer cells in 100% of metastatic lesions of the lymph nodes. VEGF expression was detected in 49 tumors (38.3%), and VEGF expression was closely correlated with COX-2 expression. The positive expression rate of VEGF (81.6%) in the cyclooxygenase-2-positive group was higher than that in the cyclooxygenase-2- negative group (18.4%, P<0.05). MMP-2 expression was detected in 88 tumors (68.8%), and MMP-2 expression was closely correlated with COX-2 expression. The positive expression rate of MMP-2 (79.6%) in the positive COX-2 group was higher than that in the negative COX-2 group (20.4%, P<0.05). Cyclooxygenase-2 may be associated with tumor progression by modulating the angiogenesis and cancer cell motility and invasive potential in colorectal cancer and it can be used as a possible biomarker.

The relationship between cyclooxygenase-2 expression and characteristics of malignant transformation in human colorectal adenomas

Cyclooxygenase 2 (COX-2) is a target of aspirin and other non-steroidal anti-inflammatory drugs and is implicated in the pathogenesis of colorectal cancer. The objective of this study was to evaluate the extent of COX-2 in pre-malignant colorectal polyps and to assess the relationship between COX-2 and the level of dysplasia in these lesions. Whole polypectomy specimens were retrieved from 123 patients by endoscopic or surgical resection. Following formalin fixation and paraffin embedding, the polyps were evaluated histologically for size, type and grade of dysplasia. The extent of COX-2 expression was measured by the avidin-biotin immunohistochemical technique using a monoclonal COX-2 antibody. The extent of COX-2 expression was graded according to percentage epithelial COX-2 expression. The polyps were of the following histological types: 10 hyperplastic, 35 tubular adenomas, 61 tubulovillous adenomas and 17 villous adenomas. Twenty showed mild dysplasia, 65 moderate dysplasia, and 28 focal or severe dysplasia (including eight with focal invasion). The average polyp size was 1.7 cm. Nine hyperplastic polyps were COX-2-negative and one was COX-2-positive. COX-2 expression was more extensive in larger polyps and in polyps with a higher villous component. There was a significant increase in the extent of COX-2 protein with increasing severity of dysplasia. Within a polyp, there was a focal corresponding increase in COX-2 expression within epithelium showing a higher grade of dysplasia. COX-2 expression is related directly to colorectal adenomatous polyp size, type and grade of dysplasia. This suggests that the role of COX-2 in colorectal cancer may be at an early stage in the adenoma-to-carcinoma sequence and supports the suggestion that inhibition of COX-2 may be useful chemoprevention for this disease.

Role of cyclooxygenase-2 in colorectal cancer.

Cyclooxygenase-2 (COX-2) is an inducible enzyme that regulates prostaglandin synthesis and is overexpressed at sites of inflammation and in several epithelial cancers. Recently, a causal link for COX-2 in epithelial tumorigenesis was shown in genetically-manipulated animal models of colon and breast carcinoma. Data indicate that COX-2 is involved in the regulation of apoptosis, angiogenesis, and tumor cell invasiveness, which appear to contribute to its effects on tumorigenesis. Multiple studies have shown that nonselective COX and selective COX-2 inhibitors effectively prevent experimental colon cancer. Furthermore, sulindac and the selective COX-2 inhibitor celecoxib were shown to regress colorectal polyps in patients with familial adenomatous polyposis. Although the exact anti-tumor mechanisms of these agents await further study, data indicate that both COX-dependent and COX-independent mechanisms may be important. In this review, the association between COX-2 and colorectal tumorigenesis and potential mechanisms of this effect are discussed. Additionally, evidence supporting the role of NSAIDs and selective COX-2 inhibitors for the prevention and treatment of human colorectal cancer is reviewed.

Expression of cyclooxygenase-2 parallels expression of interleukin-1beta, interleukin-6 and NF-kappaB in human colorectal cancer.

Elevated expression of cyclooxygenase-2 (COX-2), the inducible isoform of prostaglandin H synthase, has been found in several human cancers, including colorectal cancer (CRC). This appears as a rationale for the chemopreventive effects of non-steroidal anti-inflammatory drugs in CRC. However, the reason for COX-2 overexpression is not fully understood. In cell culture experiments, COX-2 can be induced by proinflammatory cytokines, such as interleukin (IL)-1beta and IL-6. A crucial step in this signalling pathway is thought to be activation of transcription factor NF-kappaB. Based on these findings, we hypothesized an association between COX-2 overexpression and expression of IL-1beta, IL-6 and the NF-kappaB subunit p65 in human CRC. To test the hypothesis, we performed immunohistochemistry for the respective antigens on colorectal cancer specimens, obtained by surgical resections from 21 patients with CRC. Immunohistochemical results were confirmed by examination of protein levels in tissue lysates and nuclear extracts using western blotting. Non-neoplastic tissue specimens resected well outside the tumour border served as controls. COX-2 expression was found to be markedly enhanced in the neoplastic epithelium compared with controls. This was paralleled by a significantly higher expression of IL-1beta, IL-6 and p65. Serial sections revealed consistent cellular colocalizations of respective antigens in the neoplastic epithelium. Statistically, a significant correlation between expression of COX-2 and IL-1beta, IL-6 and p65 was found. Comparable results were obtained for stromal cells like macrophages and myofibroblasts. Further examination of nuclear extracts from CRC-specimens by western blotting confirmed a higher content of p65 protein compared with non-neoplastic control tissues. Therefore, our study provides evidence for an association between expression of COX-2 and IL-1beta, IL-6 and p65 in human CRC. The results are consistent with the thesis that proinflammatory cytokines such as IL-1beta and IL-6 may be accountable for the overexpression of COX-2 in CRC. Finally, the study corroborates a role for NF-kappaB in the control of COX-2 gene transcription in CRC. Given an antiapoptotic role for COX-2 in tumour cells, inhibition of NF-kappaB may offer an important strategy to interfere with the development and progression of CRC.

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 (TNFalpha, IL-1beta, 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-1beta, 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.