Cyclooxygenase-2 Immunostaining Research Articles

CYCLOOXYGENASE 2 IS NOT OVEREXPRESSED IN POLYPS FROM JUVENILE POLYPOSIS SYNDROME PATIENTS WITH MUTANT BMPRIA

Purpose:BMPRIA is a serine-threonine kinase, TGF? superfamily type I receptor involved in protein signaling. Germline BMPRIA mutations, in addition to germline SMAD4 and PTEN mutations, have been described in kindreds with Juvenile Polyposis Syndrome (JPS), a syndrome with elevated risk for colorectal cancer. COX-2, an enzyme overexpressed in neoplastic colonic tissue, can activate Epidermal Growth Factor Receptor mitogenic activity. BMP ligands, which may be overexpressed in cells with mutant BMPRIA, negatively regulate EGF responsiveness. We characterized a JPS kindred for BMPRIA mutations, and examined the polyps for BMPRIA expression and COX2 expression. Methods: DNA analysis for BMPRIA was performed on a 21-year old male diagnosed with JPS who had a family history for JPS. Polypectomies were performed. Adenomatous change was present in several polyps. Genomic DNA was extracted from polyp material and microsatellite and LOH analyses were performed. Immunohistochemistry was performed using specific antibodies for BMPRIA and COX2. Hamartomatous polyps from patients without germline mutations in BMPRIA were used for controls. Results: The kindred possessed a germline BMPRIA missense mutation. In polyp domains containing adenomatous change, microsatellite analysis revealed novel frameshift mutations, but no LOH was observed using markers near the BMPRIA locus. Immunostaining revealed light staining for BMPRIA from the adenomatous epithelial components of the polyps, indicative of decreased expression of BMPRIA. COX2 immunostaining did not reveal overexpression in the cystic epithelium or lamiNaPropria. Conclusions: Polyps from a JPS patient with germline BMPRIA mutation showed decreased expression of BMPRIA in adenomatous epithelium, which overlapped with areas demonstrating microsatellite instability. This form of genomic instability may represent a mechanism for adenomatous change. COX2 was not overexpressed in polyps or adenomatous tissue from the BMPRIA heterozygote, suggesting an alternative mechanism for pathogenesis in these hamartomatous polyps compared with Peutz Jeghers polyps. This may imply that COX2 inhibitors would not be an effective means for chemoprevention in these polyps.

Minocycline inhibits neuronal death and glial activation induced by beta-amyloid peptide in rat hippocampus.

Minocycline, a second-generation tetracycline compound, has been examined as a neuroprotectant in beta-amyloid (A beta)-injected rat hippocampus. At 7 days post-injection, A beta(1-42) caused a significant loss of granule cell layer neurons (28% reduction) compared to control uninjected hippocampus. Hippocampal injection of A beta peptide also led to marked gliosis with numbers of microglia (increased by 26-fold) and immunoreactivity of astrocytes (increased by 11-fold) relative to control, as determined from immunohistochemical analysis. Intraperitoneal administration of minocycline significantly reduced neuronal loss induced by A beta(1-42) (by 80%) and also diminished numbers of microglia (by 69%) and astrocytes (by 36%) relative to peptide alone. Peptide injection increased expression of cyclooxygenase-2 (COX-2) in most (about 70%) of granule cells, a subset (about 20%) of microglia, but not in astrocytes; in the presence of minocycline, COX-2 immunostaining was abolished in microglia. The results from this study suggest that minocycline may have efficacy in the treatment of AD.

Cyclooxygenases and prostaglandin E synthases in the endometrium of the rhesus monkey during the menstrual cycle.

Cyclooxygenase (COX), a rate-limiting enzyme that produces prostaglandins (PGs) from arachidonic acid, exists in two isoforms, COX-1 and COX-2. PGE2 synthase (PGES) is a terminal prostanoid synthase and can enzymatically convert the cyclooxygenase product PGH2 to PGE2, including two isoforms: microsomal PGES (mPGES) and cytosolic PGES (cPGES). cPGES is predominantly linked with COX-1 to promote the immediate response. mPGES is preferentially coupled with the inducible COX-2 to promote delayed PGE2 generation. COX-2-deficient female mice are infertile with abnormalities in ovulation, fertilization, implantation and decidualization. The aim of this study was to examine immunohistochemically the expression pattern of COX-1, COX-2, mPGES and cPGES proteins in the endometrium of the rhesus monkey during the menstrual cycle. COX-1 immunostaining was mainly localized in the luminal epithelium and glandular epithelium near the lumen, and detected in all the stages during the menstrual cycle. COX-2 immunostaining was mainly localized in the luminal and glandular epithelium, and strongly shown during the mid-luteal phase (days 16 and 20) of the menstrual cycle. There was a strong cPGES immunostaining in the luminal and glandular epithelium on days 12, 16, 20 and 25 of the menstrual cycle. mPGES immunostaining was strongly detected in the glandular epithelium on days 20 and 25 of the menstrual cycle. These data suggest that the coupling of cPGES and COX-1 in the luminal epithelium may be responsible for the synthesis of PGE2 in monkey endometrium, and the coupling of mPGES and COX-2 in the glandular epithelium may be of importance for preparing the receptive endometrium.

Reciprocal expression of peroxisome proliferator-activated receptor-γ and cyclooxygenase-2 in human term parturition

Objective The objective of this study was to test the hypothesis that peroxisome proliferator activated receptor-γ (PPAR-γ) is expressed in intrauterine tissues before active term human parturition, and that its repression is associated with up-regulation of cyclooxygenase-2 (COX-2). Study Design Specimens were collected from women with term singleton pregnancies after spontaneous labor or cesarean section before labor, prepared for immunoblot and immunohistochemical analysis, and probed for PPAR-γ or COX-2. Results PPAR-γ expression was prominent in fetal membranes and placenta before active labor. After labor, PPAR-γ expression was significantly reduced in fetal membranes, but not in placenta. The ratio of COX-2:PPAR-γ was significantly elevated in fetal membranes with labor. PPAR-γ immunostaining was prominent in syncytiotrophoblast, extravillous cytotrophoblasts, and cells of the amnion and chorion. COX-2 immunostaining was abundant in the amnion and rare in the placenta. Conclusion PPAR-γ is highly expressed in term intrauterine tissues. In fetal membranes, PPAR-γ levels are reduced once active labor commences, coincidental with a relative increase in COX-2 expression.

Cyclooxygenase-2 expression in right- and left-sided colon cancer: a rationale for optimization of cyclooxygenase-2 inhibitor therapy.

Cyclooxygenase-2 (COX-2) has been identified as a potential target for prevention and therapy of human colorectal cancers (CRC) and other cancers. Because right-sided colon cancers (RSCCs) exhibit clinicopathologic and genetic differences from left-sided colorectal cancers (LSCRCs), determination of COX-2 status in these subsets of CRCs may be clinically relevant in designing COX-2 inhibitor trials for CRC and in subsequent assessment of objective therapeutic response to such therapy. Thirty-six primary CRC resection specimens (18 left, 18 right) from 36 patients were evaluated. Representative tumor sections were subjected to immunohistochemical analysis of COX-2. A semiquantitative system was used to score cytoplasmic COX-2 immunostaining. The tumors were considered COX-2 positive if more than 10% tumor cells showed COX-2 staining. Clinicopathologic and COX-2 data were compared for LSCRCs versus RSCCs. All 18 LSCRCs and 13 of 18 (72%) RSCCs were well to moderately differentiated. Overall rates of COX-2 positivity for the LSCRCs versus RSCCs were 67% (12 of 18) and 33% (6 of 18), respectively (P = 0.04). Furthermore, 11 of 12 (92%) COX-2 positive LSCRCs and 3 of 6 (50%) COX-2 positive RSCCs were stage II-IV at resection. All 12 COX-2 positive LSCRCs were associated with advanced primary tumor and 4 of 12 (33%) LCRCs had distant metastases. These associations could not be evaluated for the RSCCs because of the limited number of COX-2 positive cases. The more frequent expression of COX-2 in LSCRCs as compared with RSCCs supports the hypothesis that COX-2 expression may be related to genetic alterations specific to right- or left-sided CRCs. Further studies are needed to elucidate such relationships. Our data also suggest that stratification of patients with CRC into right- and left-sided subsets may be important in optimal patient selection for COX-2 inhibitor therapy and for subsequent assessment of objective therapeutic response.

Amelioration of hippocampal neuronal damage after transient forebrain ischemia in cyclooxygenase-2-deficient mice.

Several studies have suggested that cyclooxygenase-2 (COX-2) plays a role in ischemic neuronal death. Genetic disruption of COX-2 has been shown to reduce susceptibility to focal ischemic injury and N-methyl-d-aspartate-mediated neurotoxicity. The purpose of this study was to examine the effects of COX-2 deficiency on neuronal vulnerability after transient forebrain ischemia. Marked upregulation of COX-2 immunostaining in neurons was observed at the early stage and prominent COX-2 staining persisted in the CA1 medial sector and CA2 sector over 3 days after ischemia. The immunohistologic pattern of COX-2 staining in these sectors gradually condensed to a perinuclear location. The degree of hippocampal neuronal injury produced by global ischemia in COX-2-deficient mice was less than that in wild-type mice, coincident with attenuation of DNA fragmentation in the hippocampus. Also, treatment with a selective COX-2 inhibitor, nimesulide, after ischemia decreased hippocampal neuronal damages. These results of genetic disruption and chemical inhibition of cyclooxygenase-2 show that inhibition of COX-2 ameliorates selective neuronal death after transient forebrain ischemia in mice.

Factors involved in the inflammatory events of cervical ripening in humans

BackgroundCervical ripening is an inflammatory reaction. The glucocorticoid receptor (GR) mediates glucocorticoid anti-inflammatory reactions, whereas nuclear factor (NF)kappaB is a key pro-inflammatory transcription factor. Prostaglandins as well as platelet activating factor (PAF) are inflammatory mediators. Inducible nitric oxide synthase (iNOS) regulates the level of nitric oxide (NO) in response to various inflammatory stimuli. We hypothesize that a changed biological response to glucocorticoids could be a mechanism regulating the inflammatory events resulting in cervical ripening.MethodsWe monitored GR and NFkappaB, prostaglandin synthases cyclooxygenase (COX)-1 and -2, iNOS, as well as the PAF-receptor (PAF-R) in the uterine cervix from term pregnant women (with unripe cervices) before the onset of labor (TP), immediately after parturition (PP), as compared to non-pregnant (NP), using immunohistochemistry and RT-PCR.ResultsThe GR protein was detected by immunohistochemistry in the nuclei of stroma and squamous epithelium (SQ). Stromal GR staining was increased in TP as compared to the NP group and decreased again after parturition. GR staining in SQ was decreased after parturition as compared to term. NFkappaB was present in SQ and glandular epithelium (GE), stroma and vascular endothelium. Increased nuclear NFkappaB staining was observed postpartum as compared to term pregnancy in stroma and GE. Stromal immunostaining for COX-1 as well as COX-2 was increased in the TP and PP groups as compared to the NP, and GE displayed an intensely increased COX-2 immunostaining at term and postpartum. Stromal PAF-R immunostaining was highest at term, while it was greatly increased in GE postpartum.No difference in the immunostaining for iNOS was found between the groups. RT-PCR showed a predominance of GRalpha to GRbeta mRNA in cervical tissue. The COX-2 mRNA level was increased in the PP group as compared to the TP group.ConclusionsThere is a decrease in GR levels in human cervix at parturition. Concomitantly there is an increase of factors such as NFkappaB, PAF-R, COX-1 and COX-2, suggesting that they may participate in the sequence of events leading to the final cervical ripening.

Cyclooxygenase-1 and 2 in normal and malignant human ovarian epithelium

Objectives. Cyclooxygenase-1 and 2 (COX-1 and COX-2) play important roles in normal physiology and are often dysregulated in neoplastic tissues. The present study determines whether COX-1 and COX-2 are expressed in ovarian cancers and whether the pattern of expression of these enzymes reveals clues to their roles in this cancer. Methods. The expression of COX-1 and COX-2 proteins in 9 normal human ovaries, in 137 cases of ovarian cancers of epithelial origin (83 primary and 54 metastatic), and in 7 ovarian cancer cell lines was examined by immunohistochemistry and western analysis. Results. COX-1 protein was present in 95/137 (69.3%) of the total cancers studied, with 55/83 (66.3%) of the primary cancers and 40/54 (74.1%) of the metastatic cancers positive for protein. COX-2 was present in 97/137 (70.8%) of all cancers studied, with 53/83 (63.9%) of the primary cancers and 44/54 (81.5%) of the metastatic cancers positive for protein. Notably, the quickscores for COX-2-positive staining were significantly higher in metastatic cancers. Moreover, COX-2 immunostaining was frequently found at the advancing margin of tumor invasion or in new metastatic loci. COX-1 protein expression was observed in the ovarian surface epithelial cells, especially that of the inclusion cysts. COX-1 was also detected by western blot in seven of nine ovarian cancer cell lines. However, no COX-2 was detected in either normal epithelium or cancer cell lines. Conclusion. COX-1 and COX-2 were expressed in every type of ovarian epithelial cancer, suggesting that each may contribute to the cancer development or progression.

Cyclooxygenase-2 expression in lymph node metastasis of cervical and vulvar cancer

Overexpression of cyclooxygenase-2 (COX-2), characterizes tumors with high potential for local invasion and lymph node involvement. We investigated the expression of COX-2 in primary tumors and metastatic regional lymph nodes (TDL) from untreated and chemotherapy treated cervical cancer, as well as vulvar cancer. Immunostaining of COX-2, expressed as values of COX-2 intensity density (COX-2 IDV) was performed on 57 metastatic TDL and 24 corresponding primary rumors from 14 cervical and 9 vulvar cancer patients admitted to the Department of Obstetrics and Gynecology, Catholic University of Rome. In 6 locally advanced cervical cancer tissue samples, from both primary tumor and TDL, were obtained after chemotherapy treatment. In untreated cervical cancer, COX-2 IDV in tumor cells from positive TDL were significantly lower (median 0.69, range 0.22-0.92) than those from primary tumors (median = 3.84, range 0.19-7.67) (p=0.011). In cervical cancer exposed to chemotherapy, COX-2 IDV in tumor cells from positive TDL were significantly lower (median = 2.06, range 1.48-6.52) than those from primary tumors (median = 6.4, range 4.5-13.7) (p=0.037). In vulvar cancer COX-2 IDV in tumor cells from positive TDL were lower (median = 0.39, range 0.02-6.09) than those from primary tumors (median = 2.49, range 0.71-8.10) (p=0.04). In conclusion, we showed that COX-2 expression is down-regulated in cervical and vulvar tumor cells invading the regional lymph nodes with respect to primary tumors, thus emphasizing the need for deeper insight into the tissue specific relation between tumor cells and node microenvironment.

Increased prostaglandin E 2 concentrations and cyclooxygenase-2 expression in asthmatic subjects with sputum eosinophilia

Background Prostaglandin E 2 (PGE 2) is known to be produced within human airways, but it is not clear whether in airway diseases it can play a deleterious or a beneficial role. Recently it has been reported that PGE 2 can enhance eosinophil survival in vitro. Objective To evaluate whether the concentrations of PGE 2 in asthmatic airways correlate with the number of eosinophils and can be responsible for eosinophil-enhanced survival and to identify the cyclooxygenase isoform contributing to the synthesis of PGE 2 by cells present in asthmatic airways. Methods Reversed-phase high-performance liquid chromatography and/or specific radioimmunoassay was used to measure PGE 2 concentrations in induced sputum supernatants from 14 control and 30 asthmatic subjects. Correlations between concentrations of PGE 2 and the number of eosinophils in induced sputum were evaluated. Expression of cyclooxygenase-2 (COX-2) in induced sputum cells was determined by immunocytochemistry, and the effect of COX-2 inhibition on PGE 2 production was evaluated with the use of radiolabeled arachidonic acid. The effects on eosinophil apoptosis by PGE 2 or induced sputum supernatants were studied by using peripheral blood eosinophils obtained by negative immunomagnetic selection. Results PGE 2 concentrations resulted in elevated samples from asthmatic subjects and directly correlated with the percentage of eosinophils and the concentrations of eosinophilic cationic protein. Immunostaining for COX-2 showed enhanced expression in macrophages of asthmatic subjects when compared with control subjects, and the use of a specific COX-2 inhibitor provided evidence that PGE 2 synthesis was the result of COX-2 enzymatic activity in asthma-induced sputum cells. Supernatant from induced sputum of asthmatic subjects with high eosinophil counts caused a decreased apoptosis of peripheral blood eosinophils when compared with control subjects, and immunoprecipitation of PGE 2 significantly reverted this phenomenon, suggesting that PGE 2 was present in biologically relevant concentrations in induced sputum. Conclusions The results obtained suggest that COX-2 expression in alveolar macrophages from asthmatic subjects may contribute to enhanced eosinophil survival through an increased PGE 2 production. (J Allergy Clin Immunol 2003;112:709-16.)

Cyclooxygenase-2 promotes angiogenesis in pTa/T1 urothelial bladder carcinoma but does not predict recurrence.

To investigate the effect of cyclooxygenase-2 (COX-2) on microvessel density (MVD) and on the clinical prognosis in patients with non-muscle invasive urothelial carcinoma of the bladder, as COX-2 expression is significantly greater in epithelial tumours and there is increasing evidence that COX-2 might contribute to tumour neovascularization. We assessed tumour samples from 110 patients undergoing transurethral resection for primary pTa/pT1 bladder carcinoma (pTa, 84; pT1, 26; grade 1, 22; grade 2, 81; grade 3, seven). Paraffin sections were assessed immunohistochemically using antibodies against COX-2, CD34 (endothelial cells) and CD105 (proliferating vessels). COX-2 expression was quantified by the number of stained cells (negative, +, ++) and the MVD calculated as vessels per field. Of the 110 tumours, 45 (41%) had no immunostaining for COX-2, 40 had faint staining with at least isolated positive cells (+) and 25 stained ++. COX-2 positive tumours had significantly greater vascularization for proliferating vessels. In COX-2 negative tumours the MVD was 22.1, identified by CD34 immunostaining, and 3.4 for proliferating vessels (CD105), whereas COX-2 positive tumours had a MVD of 18.3 (CD34), and of 5.8, respectively (CD105). Complete follow-up data were available in 91 patients; after a mean follow-up of 25 months, 18 (20%) had tumour recurrences. There was no significant difference in the recurrence rates or disease-free survival between COX-2-positive (19%, 25.6 months) or -negative patients (21%, 25.2 months). These results confirm the involvement of COX-2 in angiogenesis in bladder cancer, as COX-2 promoted blood vessel proliferation in the tumour zone, and indicate the usefulness of COX-2-inhibiting drugs in preventing and treating superficial bladder cancer.

Cyclooxygenase-2 expression in uveal melanoma: novel classification of mixed-cell-type tumours

Background: The expression of cyclooxygenase-2 (COX-2), an inducible prostaglandin (PG) synthase, has been investigated in various human malignant diseases, such as cutaneous melanoma. We investigated the expression of COX-2 in uveal melanoma and related the findings to prognostic factors.Methods: In 40 cases of uveal melanoma, immunostaining for COX-2 was done. COX-2 expression was related to histopathological prognostic markers, such as cell type, the presence of lymphocytic infiltration and vascular closed loops in the tumour, and cytomorphometry results.Results: COX-2 expression was found in 58% of the cases, and it correlated with markers of poor prognosis, such as epithelioid cell type and the presence of lymphocytic infiltration and vascular closed loops. The uveal melanomas expressing COX-2 had larger nuclei, as determined by cytomorphometry.Interpretation: Whereas epithelioid tumours carry a worse prognosis than spindle cell tumours, until now it has not been possible to give a strong indication of prognosis in mixed-cell tumours. This study showed that mixed-cell tumours, representing the majority of uveal melanomas, may be further subclassified according to COX-2 expression, which serves as a marker of poor prognosis. The role of COX-2 in uveal melanoma should be further elucidated, and the use of COX-2 inhibitors warrants investigation as adjuvant treatment for this life-threatening malignant disease.

Cyclooxygenase-1 and -2 expression in urothelial carcinomas of the urinary bladder in cows.

Bovine urinary bladder tumors occur frequently in animals suffering from chronic enzootic hematuria because of prolonged ingestion of bracken fern (Pteridium spp.). Cyclooxygenase (COX) genes (COX-1 and COX-2) are known to be involved in the carcinogenesis of human and some animal urothelial tumors. The aim of the present study was to investigate COX-1 and COX-2 expression by immunohistochemical methods in 20 bovine urothelial carcinomas collected at public slaughterhouses from cows that had been suffering from chronic enzootic hematuria. COX-1 immunostaining was identified intracytoplasmically in normal urothelium and in 15 of 20 neoplastic specimens. COX-1 immunosignal in the tumor cells was either absent or weak. COX-2 was also expressed intracytoplasmically in 17 of 20 urothelial carcinomas. Moderate to intense COX-2 labeling was detected in both noninvasive and invasive urothelial carcinomas. Coexpression of both enzyme isoforms was also revealed by confocal laser scanning microscopic investigations. This study indicates that COX-2 is overexpressed in naturally occurring urothelial carcinomas of cows.

Cyclooxygenase-2 is Highly Expressed in Carcinoma in Situ and T1 Transitional Cell Carcinoma of the Bladder

We describe cyclooxygenase-2 (COX-2) expression patterns in patients with carcinoma in situ and/or stage T1 transitional cell carcinoma. We determined whether expression is associated with clinical outcome in these patients. Immunostaining for COX-2 was performed on paraffin embedded bladder biopsy specimens from 2 independent groups of patients without muscle invasive carcinoma, including 39 with carcinoma in situ and 34 with stage T1 tumors. Immunoreactivity was scored as the percent of carcinoma in situ cells with cytoplasmic staining for COX-2 in the carcinoma in situ group and as the percent of stage T1 cells expressing COX-2 in the stage T1 transitional cell carcinoma group. We evaluated other molecular alterations, including E-cadherin, p21 and p53, because evidence suggests a biological association of COX-2 with alterations in these molecular markers. In the carcinoma in situ group 5 patients (13%) had no immunoreactivity, while 2 (5%), 5 (13%) and 27 (69%) had 10%, 20% and 30% or greater carcinoma in situ cells positive for COX-2, respectively. In the transitional cell carcinoma group 1 (3%), 4 (12%) and 29 (85%) patients had 10%, 20% and 30% or greater positive cells, respectively. COX-2 expression was not associated with any clinical or pathological parameters, or with molecular markers regardless of the cutoff used. It was also not associated with clinical outcomes in the stage T1 transitional cell carcinoma group. In the carcinoma in situ group COX-2 expression was significantly associated with disease recurrence using cutoffs of 0% and greater than 10% positive cells, and with disease progression using a greater than 20% cutoff. However, it was not associated with bladder cancer related survival. COX-2 is expressed in a high percent of patients with carcinoma in situ and stage T1 transitional cell carcinoma, supporting the rationale for chemoprevention studies with selective COX-2. We could not substantiate a role for COX-2 immunohistochemistry for the staging and prognosis of carcinoma in situ and/or stage T1 transitional cell carcinoma.

The effect of selective inhibition of cyclooxygenase (COX)-2 on acute cardiac allograft rejection.

Using a rat (Lewis-Wistar Furth) abdominal heterotopic transplantation model, we reported previously that the expression of cyclooxygenase (COX)-2 is increased in parallel with that of nitric oxide synthase (NOS)-2 during cardiac allograft rejection. To investigate effects of COX-2 inhibition in this model, allograft recipients were treated orally (PO) with 5 mg/kg per day of the tetra substituted furanone selective COX-2 inhibitor 5,5-dimethyl-3-(3 fluorophenyl)-4-(4 methylsulfonal) phenyl-2 (5H)-furanone (DFU) in 1% methyl cellulose solution. In the treated animals, allograft survival was increased from 6.3+/-0.5 to 12.6+/-2.6 days (P = .001). At days 3 and 5 posttransplantation, there were reductions in the extent of the inflammatory infiltrate, endovasculitis, myocardial edema, and cardiomyocyte damage in rejecting allografts. The mean numbers of apoptotic cardiomyocytes determined with the terminal deoxynucleotide transferase-mediated dUTP nick-end labeling (TUNEL) technique were significantly reduced in DFU-treated grafts compared with untreated controls (P < 0.05). At day 3 posttransplantation, prostaglandin E2 synthesis by myocardial slices incubated with 100 microM bradykinin was reduced from 1,097+/-156 to 153+/-63 pg/mg of protein in the treated allografts (P < .005). At day 5, COX-2 protein and mRNA together with COX-2, NOS-2, and nitrotyrosine immunostaining in damaged cardiomyocytes were diminished in treated versus control grafts. The data indicate that the inhibition of COX-2 prolongs allograft survival and reduces myocardial damage and inflammation during acute cardiac allograft rejection.

ERBB-2 overexpression and cyclooxygenase-2 up-regulation in human cholangiocarcinoma and risk conditions

Quantitative immunohistochemistry of ERBB-2 and MET receptor proteins and of cyclooxygenase 2 (COX-2) was undertaken to determine if there is a positive correlation between overexpression of either ERBB-2 or MET and up-regulation of COX-2 in human cholangiocarcinogenesis. ERBB-2, MET, and COX-2 immunoreactivities were measured in cancerous parenchyma of 71 archival cases of human cholangiocarcinoma (ChC) compared with hyperplastic small biliary ducts in surrounding nonneoplastic liver and with bile ducts of normal adult human liver. ERBB-2, MET, and COX-2 immunoreactivities were also assessed in both large and small hyperplastic biliary ducts (HBDs) in 27 archival cases of hepatolithiasis and 20 archival cases of primary sclerosing cholangitis (PSC), both of which are risk conditions for human cholangiocarcinogenesis. There was a strong positive correlation between increased ERBB-2, but not MET, and COX-2 immunoreactivity measured in the tumors and risk conditions. Enhanced immunoreactivity for ERBB-2 and COX-2 also correlated directly with tumor differentiation and was highest in well-differentiated tumors. Interestingly, some but not all cases of hepatolithiasis and most cases of PSC showed increased ERBB-2 and COX-2 immunostaining in the large but not small HBDs, whereas strong MET immunostaining was detected in both the large and small ducts. In conclusion, overexpression of ERBB-2 and COX-2 may herald an early carcinogenic event in the human hepatic biliary tract and one that is consistent with a frequent anatomic site of origin of the tumors. The results also suggest ERBB-2 and COX-2 as potentially important targets relevant to chemoprevention or adjunct therapy of ChC. (H EPATOLOGY 2002;36:439-450.)

Cyclooxygenase-2 (COX-2) expression by immunohistochemistry in glioblastoma multiforme.

Cyclooxygenase-2 (COX-2) (an enzyme responsible for the conversion of arachidonic acid to prostaglandin) upregulation has been described in association with a variety of tumors including gliomas. This study reviews the immunohistochemical profile of 47 glioblastoma multiforme using COX-2 antibody and correlates the results with MIB-1 (marker of cell proliferation) immunostaining. Positive staining with COX-2 was observed in 35 tumors (74.5%); more than 10% tumor cell positivity was seen in 10 tumors (21.3%). Immunostaining results were as follows: no staining, N = 12 (25.5%); 0% to 5% of tumor cells, N = 20 (42.6%); 5% to 10%, N = 5 (10.6%); 10% to 20%, N = 4 (8.5%); 20% to 50%, N = 4 (8.5%); and greater than 50%, N = 2 (4.3%). The mean MIB-1 labeling index for all tumors ranged from 3.0 to 76.4 (mean, 19.6). Mean MIB-1 labeling indices were higher in tumors with greater than 5% COX-2 immunostaining (mean MIB-1 labeling index, 23.5) versus tumors with 0% to 5% COX-2 immunostaining (mean MIB-1 labeling index, 17.7). There is evidence of COX-2 expression by immunohistochemistry in the majority of glioblastoma multiforme. As a group, tumors with a higher rate of cell proliferation tended to have increased expression of COX-2. These findings are significant in that therapeutic agents, which inhibit COX-2, are currently available and may play a role in the management of glioblastoma multiforme.

Cyclooxygenase-2 Expression and Relationship to Malignant Potential in Human Bladder Cancer.

Cyclooxygenase (COX), which catalyzes the synthesis of prostaglandins from arachidonic acid, has two isoforms; COX-1 and COX-2. A large body of evidence exists to suggest that COX-2 is important in gastrointestinal cancer. In order to determine whether COX-2 is expressed in transitional cell carcinoma (TCC) of the human bladder as well as in gastrointestinal cancer, we investigated COX-2 expression in human TCC by Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and immunohistochemical analysis, and we found that normal bladder epithelium did not express COX-2 and that COX-2 was markedly up-regulated in human bladder TCC. In nontumor tissues, COX-2 immunostaining signals were observed only in lymphoid follicles. Furthermore, the intensity and extent of COX-2 immunostaining in the bladder cancer tissues were scored and the relationship to tumor grade and stage was investigated. The levels of COX-2 expression were correlated with the tumor grade; from grades 1 to 3, there was a stepwise increase in the COX-2 immunostaining score. These findings suggested that an increase in COX-2 expression may be associated with bladder carcinogenesis as well as gastrointestinal carcinogenesis, and that it may be useful as a biomarker in bladder cancer.

The expression of cyclooxygenase-1 and -2 in proliferative endometrium and endometrial adenocarcinoma

BACKGROUND. The activity of cyclooxygenase-2 (COX-2) is increased in inflammation and in several cancer types. We investigated the expression of COX-2, cyclooxygenase-1 (COX-1), nitric oxide synthase-2 (NOS-2) and nitric oxide synthase-3 (NOS-3) in normal proliferative and secretory human endometrium, and in endometrial adenocarcinoma. METHODS. Human endometrium was collected at hysterectomy. Seven samples were in proliferative and 11 samples in secretory stage. Twelve specimens from endometrial carcinoma were collected, as well. Immunohistochemistry was used to investigate the expression of COX-1, COX-2, NOS-2 and NOS-3. RESULTS. COX-2 immunostaining was detected in most specimens of normal proliferative glandular epithelium (86%) and of endometrial carcinomas (92%). COX-2 staining was often detected in cancer cells on the border areas of the tumour and on the areas of invasive growth. Staining for COX-2 was seen in proliferative glands usually only in the basal layer of the endometrium. NOS-2 was usually absent or negligible in proliferative endometrial glands and also in the cancer cells of endometrial adenocarcinomas. No staining for either COX-2 or NOS-2 was seen in specimens of secretory glandular epithelium. The expression of the constitutive COX-1 and NOS-3 was negligible or weak in the glandular epithelium of proliferative and secretory endometrium and in endometrial cancer cells. CONCLUSIONS. The expression of the inducible COX-2 but not of COX-1 is stimulated in the glandular epithelium of proliferative endometrium and in the cancer cells of human endometrial adenocarcinoma, in particular in those in the borders of carcinoma and spreading into lymphatic vessels.

Expression of cyclooxygenase-2 protein in colorectal carcinomas.

Overexpression of cyclooxygenase-2 (COX-2) has been demonstrated in various human cancers, including colorectal cancer. Thus, overexpression of COX-2 may be involved in the growth and progression of cancer, and this may have prognostic significance. The aim of our study is to evaluate the expression of COX-2 in colorectal cancer tissue, and to examine the relationship of its expression to various clinicopathological parameters and patient survival. Formalin-fixed, paraffin-embedded tissue blocks were obtained from 60 patients who underwent surgery for colorectal carcinoma in 1995 at the Chonnam National University Hospital in Gwangju, Korea. We have used an immunohistochemical technique to localize COX-2 in colorectal carcinoma tissues. Immunohistochemical staining of the colorectal cancer specimens demonstrated that COX-2 expression was localized to the carcinoma cells and was not detectable in the stromal compartment of the cancers. The COX-2 immunostaining pattern was predominantly homogenous, and perinuclear cytoplasmic within the tumors. Normal colonic epithelium adjacent to the tumor showed no staining for COX-2. The COX-2 protein was detected in 70% (42/60) of colorectal carcinoma tissues. However, no significant correlation was found between COX-2 expression and various clinicopathological parameters, including histologic grade, tumor size, depth of invasion, lymph node metastasis, distant metastasis, or stage. Furthermore, COX-2 expression did not correlate with patient survival (p = 0.401). These results suggest that COX-2 expression may play an important role in the evolution of colon carcinogenesis. However, further studies are needed to determine the prognostic relevance of COX-2.