RNA profiling of cyclooxygenases 1 and 2 in colorectal cancer

Abstract

Cyclooxygenases (particularily Cox-2) are involved in carcinogenesis and metastatic cancer progression. The expression profiles of the cyclooxygenases and the roles they play in established tumours of similar stage remains unclear. We report that Cox-1 and Cox-2 expression is highly variable in Dukes' C tumours, and changes in Cox-1 expression may be of importance.

Distinct expression pattern of the full set of secreted phospholipases A2 in human colorectal adenocarcinomas: sPLA2-III as a biomarker candidate

“…The slight decrease in PLA2G4A expression that we observed may be related to the dual opposing effects of cPLA 2 -IVA in cancer, that is, proliferative effects via metabolism of AA into eicosanoids, such as PGE 2 , and antiproliferative effects via AA-dependent ceramide production leading to apoptosis . The absence of increase in ptgs2 (the COX-2 gene) levels in our set of patients is in accordance with two recent qPCR studies also performed on patients with colon cancer (Church et al, 2004;Gustafsson et al, 2007), and may be related to the inflammatory status of the normal mucosa discussed above. The fact that we did not observe an increase of COX-2 at the mRNA level, while we detected an overexpression at the protein level by immunohistochemistry as previously reported (Wendum et al, 2003), is in line with the posttranscriptional regulation of COX-2 expression (Dixon et al, 2003).…”

“…Therefore, our data would suggest a possible pre-existing inflammatory condition within the normal mucosa distant from the tumours, and likely explain the absence of increased expression in adenocarcinomas vs normal mucosa for several inflammation-related genes. The slight decrease in ptgs1 (the COX-1 gene) appeared in agreement with that observed in colon adenocarcinomas of stage III (Duke's C) patients (Church et al, 2004). The COX-1 protein is considered to exert dual opposing effects in cancer, acting as either a tumour suppressor or a tumour initiator (Chulada et al, 2000).…”

Physiological concentrations of butyrate favorably modulate genes of oxidative and metabolic stress in primary human colon cells

“…Cyclooxygenases are responsible for the metabolism of arachidonic acid into prostaglandins. There are two isoforms, the constitutively expressed COX-1 and the inducible COX-2, of which the latter is implicated in tumorigenesis and cancer progression [53]. Altogether, the reduction of inflammatory processes may represent a feasible approach of chemoprevention in healthy cells.…”

Cyclooxygenase-1 (COX-1) and COX-1 Inhibitors in Cancer: A Review of Oncology and Medicinal Chemistry Literature

“…Many evidences exist underlying the pathophysiological link between chronic inflammation and colorectal cancer [66], and the role of COX-2 in the carcinogenesis process has been extensively investigated [67,68]. COX-1 and COX-2 mRNA expression profiles were examined in tumor tissue in comparison to normal mucosa in stage III (Dukes’ C) colorectal cancer patients by Church et al [69]. In contrast to the general opinion that constitutive COX-1 was not subject to variable expression, an altered regulation of COX-1 expression between normal and malignant tissues was reported, consistent with a COX-1 role in tumorigenesis.…”