Overexpression of cyclooxygenase-2 in human prostate carcinoma and prostatic intraepithelial neoplasia-association with increased expression of Polo-like kinase-1

COX-2 mediates pro-tumorigenic effects of PKCε in prostate cancer

The pro-oncogenic kinase PKCε is overexpressed in human prostate cancer and cooperates with loss of the tumor suppressor Pten for the development of prostatic adenocarcinoma. However, the effectors driving PKCε-mediated phenotypes remain poorly defined. Here, using cellular and mouse models, we showed that PKCε overexpression acts synergistically with Pten loss to promote NF-κB activation and induce cyclooxygenase-2 (COX-2) expression, phenotypic traits which are also observed in human prostate tumors. Targeted disruption of PKCε from prostate cancer cells impaired COX-2 induction and PGE2 production. Notably, COX-2 inhibitors selectively killed prostate epithelial cells overexpressing PKCε, and this ability was greatly enhanced by Pten loss. Long-term COX-2 inhibition markedly reduced adenocarcinoma formation, as well as angiogenesis in a mouse model of prostate-specific PKCε expression and Pten loss. Overall, our results provide strong evidence for the involvement of the canonical NF-κB pathway and its target gene COX2 as PKCε effectors, and highlight the potential of PKCε as a useful biomarker for the use of COX inhibition for chemopreventive and/or chemotherapeutic purposes in prostate cancer.

Effects of tumour necrosis factor α upon the metabolism of the endocannabinoid anandamide in prostate cancer cells

Tumour necrosis factor α (TNFα) is involved in the pathogenesis of prostate cancer, a disease where disturbances in the endocannabinoid system are seen. In the present study we have investigated whether treatment of DU145 human prostate cancer cells affects anandamide (AEA) catabolic pathways. Additionally, we have investigated whether cyclooxygenase-2 (COX-2) can regulate the uptake of AEA into cells. Levels of AEA synthetic and catabolic enzymes were determined by qPCR. AEA uptake and hydrolysis in DU145 and RAW264.7 macrophage cells were assayed using AEA labeled in the arachidonic and ethanolamine portions of the molecule, respectively. Levels of AEA, related N-acylethanolamines (NAEs), prostaglandins (PG) and PG-ethanolamines (PG-EA) in DU145 cells and medium were quantitated by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis. TNFα treatment of DU145 cells increased mRNA levels of PTSG2 (gene of COX-2) and decreased the mRNA of the AEA synthetic enzyme N-acyl-phosphatidylethanolamine selective phospholipase D. mRNA levels of the AEA hydrolytic enzymes fatty acid amide hydrolase (FAAH) and N-acylethanolamine-hydrolyzing acid amidase were not changed. AEA uptake in both DU145 and RAW264.7 cells was inhibited by FAAH inhibition, but not by COX-2 inhibition, even in RAW264.7 cells where the expression of this enzyme had greatly been induced by lipopolysaccharide + interferon γ treatment. AEA and related NAEs were detected in DU145 cells, but PGs and PGE2-EA were only detected when the cells had been preincubated with 100 nM AEA. The data demonstrate that in DU145 cells, TNFα treatment changes the relative expression of the enzymes involved in the hydrolytic and oxygenation catabolic pathways for AEA. In RAW264.7 cells, COX-2, in contrast to FAAH, does not regulate the cellular accumulation of AEA. Further studies are necessary to determine the extent to which inflammatory mediators are involved in the abnormal endocannabinoid signalling system in prostate cancer.

Expression of CD24, a Stem Cell Marker, in Pancreatic and Small Intestinal Neuroendocrine Tumors

OBJECTIVES

CD24 has been considered a normal and cancer stem cell marker. Potential intestinal stem cells weakly express CD24. In the pancreas, CD24 is a possible cancer stem cell marker for ductal adenocarcinoma.

METHODS

Expression of CD24 in intestinal and pancreatic neuroendocrine tumors (NETs) was examined. Immunohistochemistry was performed on benign duodenum, ileum mucosa, and pancreas, as well as primary duodenal, primary and metastatic ileal, and pancreatic NETs.

RESULTS

Scattered CD24-positive cells were noted in the duodenal and ileal crypts, most of which showed a strong subnuclear labeling pattern. Similar expression was observed in 41 (95%) of 43 primary ileal NETs but in only four (15%) of 26 duodenal NETs (P < .01). In addition, metastatic ileal NETs retained CD24 expression. Pancreatic islets did not express CD24, and only rare cells had subnuclear labeling of CD24 in the pancreatic ducts. Unlike ileal NETs, only five (5%) of 92 pancreatic NETs expressed CD24 in the subnuclear compartment (P < .01). All five NETs showed a unique morphology with prominent stromal fibrosis.

CONCLUSIONS

CD24 expression was frequent in primary and metastatic midgut NETs but rare in pancreatic and duodenal NETs. Expression of CD24 in ileal NETs may have future diagnostic and therapeutic implications.

Systematic review and meta-analysis of COX-2 expression and polymorphisms in prostate cancer

Evidence is accumulating that cyclooxygenase-2 (COX-2) may play an important role in prostate cancer (PCa). Recently, gene polymorphisms in COX-2 have been implicated to alter the risk of PCa and overexpression of COX-2 may be associated with clinical and prognostic significance in PCa. However, the results of these studies are inconclusive or controversial. To derive a more precise estimation of the relationships, we performed an updated meta-analysis. A comprehensive search was conducted to examine all the eligible studies of COX-2 polymorphism and expression in PCa. We used odds ratios (ORs) to assess the strength of the association and the 95 % confidence intervals (CIs) give a sense of the precision of the estimate. Overall, no significant associations between COX-2 polymorphism and PCa risk were found. However, high expression of COX-2 was significantly higher in T3-T4 stages of PCa than in T1-T2 stages of PCa (OR = 2.33, 95 %CI: 1.54-3.53, P < 0.0001). COX-2 might play an important role in the progress of PCa, overexpression of COX-2 correlates with T3-T4 stages of PCa. COX-2 might be a potential therapy target for PCa and work as a prognostic factor for PCa patients.

Association between COX-2 rs2745557 polymorphism and prostate cancer risk: a systematic review and meta-analysis

Background

Evidence is accumulating that chronic inflammation may have an important role in prostate cancer (PCa). The COX-2 polymorphism rs2745557 (+202 C/T) has been extensively investigated as a potential risk factor for PCa, but the results have thus far been inconclusive. This meta-analysis was performed to derive a more precise estimation of the association.

Methods

A comprehensive search was conducted to identify all case-control studies of COX-2 rs2745557 polymorphism and PCa risk. We used odds ratios (ORs) to assess the strength of the association, and 95% confidence intervals (CIs) give a sense of the precision of the estimate. Statistical analyses were performed by Review Manage, version 5.0 and Stata 10.0.

Results

A total of 8 available studies were considered in the present meta-analysis, with 11356 patients and 11641 controls for rs2745557. When all groups were pooled, there was no evidence that rs2745557 had significant association with PCa under co-dominant, recessive, over-dominant, and allelic models. However, our analysis suggested that rs2745557 was associated with a lower PCa risk under dominant model in overall population (OR = 0.85, 95%CI = 0.74-0.97, P = 0.02). When stratifying for race, there was a significant association between rs2745557 polymorphism and lower PCa risk in dominant model comparison in the subgroup of Caucasians (OR = 0.86, 95%CI = 0.75-0.99, P = 0.04), but not in co-dominant, recessive, over-dominant and allelic comparisons.

Conclusion

Based on our meta-analysis, COX-2 rs2745557 was associated with a lower PCa risk under dominant model in Caucasians.

Cyclooxygenase-2 overexpression in chronic inflammation associated with benign prostatic hyperplasia: is it related to apoptosis and angiogenesis of prostate cancer?

Purpose

This study was performed to investigate the relationship between cyclooxygenase-2 (COX-2) expression and apoptosis/angiogenesis in inflammatory and noninflammatory benign prostatic hyperplasia (BPH) and prostate cancer (PC).

Materials and Methods

This study involved 64 BPH and 57 PC patients. The BPH histopathologies were classified by the presence of chronic inflammation as follows: noninflammatory BPH (NI-BPH; n=23) and inflammatory BPH (I-BPH; n=41). The association between the expression of COX-2, expression of Bcl-2, the apoptotic index (AI), expression of vascular endothelial growth factor (VEGF), and microvascular density (MVD) in the prostate was investigated.

Results

An overexpression of COX-2, Bcl-2, and VEGF was observed in cases of PC compared with cases of BPH. In PC, the AI was lower and MVD was higher than in BPH. In NI-BPH, I-BPH, and PC, the overexpression of COX-2, Bcl-2, and VEGF gradually increased. The AI was high in I-BPH, but did not differ significantly between the NI-BPH and I-BPH groups or between the NI-BPH and PC groups. MVD was significantly high in PC, but no significant difference was found between NI-BPH and I-BPH. A significant correlation was shown between the overexpression of COX-2 and Bcl-2, and COX-2 and VEGF. However, the AI was not correlated with the overexpression of COX-2 or Bcl-2. MVD was correlated with the overexpression of COX-2 and VEGF.

Conclusions

COX-2 overexpression in PC is correlated with a decrease in apoptosis and an increase in angiogenesis. Chronic inflammation in BPH causes an overexpression of COX-2, which induces the increased expression of Bcl-2 and VEGF. It is likely that chronic inflammation plays a role in the intermediate step of carcinogenesis in the prostate.

Role of senescence and mitotic catastrophe in cancer therapy

Senescence and mitotic catastrophe (MC) are two distinct crucial non-apoptotic mechanisms, often triggered in cancer cells and tissues in response to anti-cancer drugs. Chemotherapeuticals and myriad other factors induce cell eradication via these routes. While senescence drives the cells to a state of quiescence, MC drives the cells towards death during the course of mitosis. The senescent phenotype distinguishes tumor cells that survived drug exposure but lost the ability to form colonies from those that recover and proliferate after treatment. Although senescent cells do not proliferate, they are metabolically active and may secrete proteins with potential tumor-promoting activities. The other anti-proliferative response of tumor cells is MC that is a form of cell death that results from abnormal mitosis and leads to the formation of interphase cells with multiple micronuclei. Different classes of cytotoxic agents induce MC, but the pathways of abnormal mitosis differ depending on the nature of the inducer and the status of cell-cycle checkpoints. In this review, we compare the two pathways and mention that they are activated to curb the growth of tumors. Altogether, we have highlighted the possibilities of the use of senescence targeting drugs, mitotic kinases and anti-mitotic agents in fabricating novel strategies in cancer control.

Association of nonsteroidal anti-inflammatory drugs, prostate specific antigen and prostate volume

PURPOSE

Nonsteroidal anti-inflammatory drugs such as aspirin prevent cardiovascular disease and several prior studies suggest that nonsteroidal anti-inflammatory drugs also decrease prostate inflammation and prostate cancer risk. We investigated the association between nonsteroidal anti-inflammatory drug use, prostate specific antigen and prostate volume, hypothesizing that there would be lower prostate specific antigen and prostate volume with nonsteroidal anti-inflammatory drug use.

MATERIALS AND METHODS

The Nashville Men's Health Study uses a multicenter, rapid recruitment protocol to collect clinical, biological, behavioral and body measurement data on 1,277 men older than 40 years who are scheduled for diagnostic prostate biopsy. Nonsteroidal anti-inflammatory drug use was ascertained by survey and clinical interview. Medical charts were reviewed to ascertain current prostate specific antigen, prostate volume and clinical diagnoses following biopsy.

RESULTS

Approximately 46% of patients reported receiving nonsteroidal anti-inflammatory drugs, primarily aspirin (37%). After adjusting for age, race and other factors prostate volume was similar between aspirin users and nonusers (47.6 vs 46.0 ml, p = 0.16). In contrast, prostate specific antigen was significantly lower in aspirin users (7.3 vs 8.0 ng/ml, p = 0.01). The association between prostate specific antigen and aspirin was significant in men with latent prostate cancer (6.1 vs 7.3 ng/ml, p <0.01), marginal in patients with high grade prostatic intraepithelial neoplasia (5.0 vs 5.9 ng/ml, p = 0.09) and nonsignificant in those with a negative biopsy (5.6 vs 5.7 ng/ml, p = 0.64). The strongest prostate specific antigen-aspirin association was in men with cancer and a prostate volume of 60 ml or more (7.3 vs 12.7 ng/ml, p <0.01).

CONCLUSIONS

Prostate specific antigen was significantly lower in aspirin users with latent cancer. Prostate volume was not associated with nonsteroidal anti-inflammatory drug use. Results suggest that aspirin may affect prostate cancer detection, suggesting a potential detection bias to address in future studies of nonsteroidal anti-inflammatory drugs and prostate cancer prevention.

SmgGDS is up-regulated in prostate carcinoma and promotes tumour phenotypes in prostate cancer cells

SmgGDS is a guanine nucleotide exchange factor with the unique ability to activate multiple small GTPases, implicating it in cancer development and progression. Here, we investigated the role of SmgGDS in prostate cancer by studying the expression of SmgGDS in benign and malignant prostatic tissues. We also probed SmgGDS function in three prostate carcinoma cell lines using small interfering RNA (siRNA). Immunohistochemical analysis revealed that SmgGDS levels were elevated in prostatic intraepithelial neoplasia (PIN), prostate carcinoma, and metastatic prostate carcinoma. In addition, expression of SmgGDS positively correlated with that of cyclooxygenase-2 (COX-2), a protein believed to promote the development of prostate carcinoma. Reduction of SmgGDS expression in prostate carcinoma cells inhibited proliferation and migration, irrespective of androgen receptor status. These effects were accompanied by a reduction in COX-2 expression and in activity of NF-kappaB, a known regulator of COX-2. Taken together, these findings suggest that SmgGDS promotes the development and progression of prostate cancer, possibly associated with NF-kappaB-dependent up-regulation of COX-2.

Proteomics-based approach to elucidate the mechanism of antitumor effect of curcumin in cervical cancer

Cervical cancer is the second leading cause of cancer death for women in the world. A potential target for preventing and treating cervical cancer is cyclooxygenase-2 (cox-2). Curcumin is an anti-inflammatory agent that is known to have anti-cox-2 activity. In this study we examined the expression of cox-2 in cervical cancer and its precursors by immunohistochemistry. The effect of curcumin in inhibiting cervical cancer cells was determined via 2-dimensional gel electrophoresis, data analysis, and ingenuity pathway analysis. No significant differences in the expression of cox-2 in squamous cell carcinoma, and carcinoma in situ were observed. However, there was a statistically significant difference in the expression of cox-2 in adenocarcinoma in comparison to normal (p value=0.01) and squamous cell carcinoma (p value=0.02) tissues. Proteins associated with cancer and cell cycle were significantly altered in cultured cells. Curcumin may have antitumor effect in cervical cancer.

COX-2 promoter polymorphisms and the association with prostate cancer risk in South African men

Cyclooxygenase-2 (COX-2) converts arachidonic acid to prostaglandins, which are important mediators of cell proliferation and inflammation. Evidence indicates that COX-2 plays a role in carcinogenesis and that it is over-expressed in prostate tumours. We investigated the role of COX-2 variants in prostate cancer in a case-control study of South African Coloured men, consisting of 151 cases and 134 controls. The genotype frequencies of four single-nucleotide polymorphisms (SNPs) in the COX-2 promoter were initially determined in 50 control subjects. One SNP, rs20417 (-899G>C), was monomorphic and excluded from further investigation. Three SNPs, rs3918304 (-1285A>G), rs20415 (-1265C>T) and rs5270 (-297C>G), were genotyped in all the case patients and control subjects. The -1285 G-allele and -1265 T-allele were associated with increased risk of prostate cancer [odds ratio (OR) = 3.53; confidence interval (CI) = 2.14-5.90; P < 0.0001 and OR = 3.01; CI = 1.82-5.02; P < 0.0001] after adjusting for age. Haplotype GTC conferred increased risk of prostate cancer in South African Coloured men (OR = 3.54 versus ACC; CI = 2.12-5.92; P < 0.0001). These findings in conjunction with findings in other populations of African descent might suggest a common causal variant for prostate cancer in COX-2, or a variant in a nearby gene.

Overexpression of ELAV-like protein HuR is associated with increased COX-2 expression in atrophy, high-grade prostatic intraepithelial neoplasia, and incidental prostate cancer in cystoprostatectomies

BACKGROUND

The human ELAV-like protein HuR regulates the stability of several mRNA targets, including that of cyclooygenase-2 (COX-2). Their expression in prostatic carcinogenesis is uncertain.

OBJECTIVE

To analyze HuR and COX-2 expression in cystoprostatectomies (CyPs) with incidental prostate cancer and compare their expression with those in radical prostatectomies (RPs) with clinically detected cancer.

DESIGN, SETTING, AND PARTICIPANTS

HuR and COX-2 were immunohistochemically evaluated in normal-looking epithelium (NEp), atrophy, high-grade prostatic intraepithelial neoplasia (HGPIN), and prostate carcinoma (PCa) in 20 CyPs and 20 RPs, both types of specimens with pT2a Gleason score 6 PCa.

MEASUREMENTS

At least 1000 cells were counted in contiguous 400X microscopic fields in each case, separately for NEp, atrophy, HGPIN, and PCa.

RESULTS AND LIMITATIONS

There was an increase in the percentage of secretory cells with cytoplasmic HuR staining from NEp to atrophy, HGPIN, and PCa. The mean percentages in NEp, atrophy, and HGPIN adjacent to PCa were greater than away from cancer, both in the CyP and RPs. There was a trend towards a reduced nuclear HuR expression in atrophy, HGPIN, and PCa, compared to NEp. COX-2 staining was seen in the cytoplasm of the basal and secretory cells. There was a reduction in the mean proportion of positive basal cells and progressive increase in the percentage of positive secretory cells from atrophy to HGPIN and PCa, compared to NEp. Cytoplasmic HuR overexpression was correlated with COX-2 expression. There was no difference in HuR and COX-2 expression between cancers with tumour volume <0.5 ccm or >0.5 ccm. The limitations of this study were the small number of cases investigated and lack of a control group without cancer.

CONCLUSIONS

The secretory cells showed shift in HuR staining from nuclear in NEp to cytoplasmic in PCa. This is associated with a parallel shift in COX-2 expression from basal to secretory cells.

Exisulind in combination with celecoxib modulates epidermal growth factor receptor, cyclooxygenase-2, and cyclin D1 against prostate carcinogenesis: in vivo evidence

PURPOSE

Nonsteroidal anti-inflammatory drugs mediate anticancer effects by modulating cyclooxygenase-2 (COX-2)-dependent and/or COX-2-independent mechanism(s); however, the toxicity issue is a concern with single agents at higher doses. In this study, we determined the combined effect of celecoxib, a COX-2 inhibitor, along with exisulind (sulindac sulfone/Aptosyn) at low doses in prostate cancer.

EXPERIMENTAL DESIGN

We used a sequential regimen of N-methyl-N-nitrosourea + testosterone to induce prostate cancer in Wistar-Unilever rats. Following carcinogen treatment, celecoxib and exisulind individually and their combination at low doses were given in NIH-07 diet for 52 weeks. We determined the incidence of prostatic intraepithelial neoplasia, adenocarcinomas, rate of tumor cell proliferation, and apoptosis. Immunohistochemical and Western blot analysis were done to determine COX-2, epidermal growth factor receptor (EGFR), Akt, androgen receptor, and cyclin D1 expression. Serum prostaglandin E2 and tumor necrosis factor-alpha levels were determined using enzyme immunoassay/ELISA assays.

RESULTS

The rats that received celecoxib in combination with exisulind at low doses showed a significant decrease in prostatic intraepithelial neoplasia and adenocarcinomas as well as an enhanced rate of apoptosis. An overall decrease in COX-2, EGFR, Akt, androgen receptor, and cyclin D1 expression was found associated with tumor growth inhibition. Reduced serum levels of COX-2 protein, prostaglandin E2, and tumor necrosis factor-alpha indicated anti-inflammatory effects. A strong inhibition of total and phosphorylated form of EGFR (Tyr(992) and Tyr(845)) and Akt (Ser(473)) was significant in rats given with these agents in combination.

CONCLUSIONS

In this study, we show for the first time that the combination of celecoxib with exisulind at low doses could prevent prostate carcinogenesis by altering key molecular events.