The role of cyclooxygenase-2 in cell proliferation and cell death in human malignancies. Int J Cell Biol. 2010;2010:215158. [PMID: 20339581 PMCID: PMC2841246 DOI: 10.1155/2010/215158]

Distribution of cyclooxygenases 1 and 2 in the uterus and breast of cynomolgus monkeys-effects of hormone treatment

OBJECTIVE

The aim of this study was to compare the distribution and immunoreactivity of cyclooxygenase (COX) 1 and COX-2 in normal uterus and breast after long-term hormone therapy in postmenopausal monkeys.

METHODS

Female adult cynomolgus macaques were bilaterally ovariectomized 3 months before the initiation of hormone treatment. The animals were either treated (experiment 1) with conjugated equine estrogens (CEE), medroxyprogesterone acetate (MPA), CEE + MPA, or tamoxifen or designated as controls (C). In experiment 2, the animals were either treated with CEE, CEE + MPA, or tibolone or designated as C. Breast tissue and uteri were collected, fixed, and paraffin embedded. Immunohistochemistry assays for COX-1 and COX-2 were performed.

RESULTS

COX-1 immunostaining was decreased by tamoxifen and CEE treatment in the endometrial stroma and by CEE + MPA in the myometrium. COX-1 immunostaining of the breast epithelia was down-regulated by CEE + MPA, whereas other cell types in the breast seem to be less affected by hormone treatment.COX-2 immunoreactivity in the endometrial stroma was increased by CEE + MPA. In the glandular epithelium, CEE + MPA and tibolone treatment increased COX-2 immunostaining compared with CEE treatment only and no treatment at all (C). No effect from hormone treatment on COX-2 immunostaining was found in the myometrium. COX-2 immunostaining in the glandular epithelium of the breast was, in experiment 2, increased after CEE treatment compared with no treatment (C). No other effects by hormone therapy on COX-2 expression were found in the breast.

CONCLUSIONS

Our results show that COX-1 and COX-2 are differently distributed and regulated by hormones in the normal uterus and breast of ovariectomized macaques. COX-1 is prevailing in the uterus, whereas COX-2 is dominant in the mammary gland.

Cancer cell signaling pathways targeted by spice-derived nutraceuticals

Extensive research within the last half a century has revealed that cancer is caused by dysregulation of as many as 500 different gene products. Most natural products target multiple gene products and thus are ideally suited for prevention and treatment of various chronic diseases, including cancer. Dietary agents such as spices have been used extensively in the Eastern world for a variety of ailments for millennia, and five centuries ago they took a golden journey to the Western world. Various spice-derived nutraceuticals, including 1'-acetoxychavicol acetate, anethole, capsaicin, cardamonin, curcumin, dibenzoylmethane, diosgenin, eugenol, gambogic acid, gingerol, thymoquinone, ursolic acid, xanthohumol, and zerumbone derived from galangal, anise, red chili, black cardamom, turmeric, licorice, fenugreek, clove, kokum, ginger, black cumin, rosemary, hop, and pinecone ginger, respectively, are the focus of this review. The modulation of various transcription factors, growth factors, protein kinases, and inflammatory mediators by these spice-derived nutraceuticals are described. The anticancer potential through the modulation of various targets is also the subject of this review. Although they have always been used to improve taste and color and as a preservative, they are now also used for prevention and treatment of a wide variety of chronic inflammatory diseases, including cancer.

Role of cyclooxygenase-2 gene polymorphisms in pancreatic carcinogenesis

AIM: To evaluate the clinical significance of -765G/C and -1195G/A cyclooxygenase-2 (COX-2) gene polymorphisms in patients with pancreatic cancer (PC).

METHODS: The study included 201 patients: 85 with PC and 116 healthy controls. -765G/C and -1195G/A COX-2 gene polymorphisms were studied in DNA isolated from blood samples. The associations of the analyzed genotypes and clinical data at diagnosis were evaluated.

RESULTS: We found an increased frequency of the homozygous -1195AA COX-2 genotype in patients with PC (53.7%) compared with the control group (21%) (P < 0.01). In contrast, the distribution of genotype and allele frequencies of the -765G/C COX-2 polymorphism in the PC patients were not different from those in control groups. A correlation between presence of homozygous -1195AA COX-2 genotype and tumor size > 3 cm was observed (P < 0.05). Analyzed polymorphisms were unrelated to the patients’ sex and age, nor to the presence of regional or distant metastases.

CONCLUSION: These preliminary results indicate that the -1195G/A COX-2 polymorphism may play an important role in PC prognosis and carcinogenesis.

Differentially expressed genes in window trials are influenced by the wound-healing process: lessons learned from a pilot study with anastrozole

BACKGROUND

Perioperative window trials provide an opportunity to obtain intact tumor samples at two different time-points for evaluation of potential surrogate biomarkers. We report results of a pilot trial designed to determine if treatment-mediated changes in gene expression can be detected in formalin-fixed paraffin-embedded (FFPE) samples after 10-d exposure to anastrozole in estrogen receptor (ER)-positive breast cancer compared with untreated controls.

METHODS

Paired tumor samples (biopsy, surgical) were obtained from 26 postmenopausal women with ER-positive breast cancer. Patients were assigned anastrozole (1 mg/d) for 10 d immediately prior to surgery (13 cases) or no treatment (13 controls). Five hundred two cancer-related genes were examined by the Illumina cDNA-mediated annealing, selection, extension, and ligation, FFPE cDNA array (moderated t-test, P ≤ 0.005). Surrogate biomarkers reflecting changes in gene expression were examined by immunohistochemistry (Wilcoxon rank-based test, P < 0.05).

RESULTS

Sufficient RNA was available from 19 paired samples (8 controls, 11 cases). Frozen tissue and FFPE showed good correlation (r = 0.82). Within each group, 18 genes, reflecting roles in proliferation, angiogenesis, and apoptosis, showed differential expression from biopsy to surgery (P < 0.005). Estrogen-related genes were dysregulated in the treated group only. A reduction in Ki-67 was observed in 7 (54%) treated cases and in 1 (7.7%) control patient.

CONCLUSIONS

10-d exposure to anastrozole resulted in dysregulation of 18/502 cancer-related genes, and Ki-67 was reduced in 54% of cases. FFPE samples demonstrated good correlation with frozen samples. However, changes in gene expression and increased Ki-67 in the control group suggest local effects of wound healing may represent a confounding factor in the interpretation of perioperative window trials.

COX-2 inhibitors block chemotherapeutic agent-induced apoptosis prior to commitment in hematopoietic cancer cells

Enzymatic inhibitors of pro-inflammatory cyclooxygenase-2 (COX-2) possess multiple anti-cancer effects, including chemosensitization. These effects are not always linked to the inhibition of the COX-2 enzyme. Here we analyze the effects of three COX-2 enzyme inhibitors (nimesulide, NS-398 and celecoxib) on apoptosis in different hematopoietic cancer models. Surprisingly, COX-2 inhibitors strongly prevent apoptosis induced by a panel of chemotherapeutic agents. We selected U937 cells as a model of sensitive cells for further studies. Here, we provide evidence that the protective effect is COX-independent. No suppression of the low basal prostaglandin (PG)E(2) production may be observed upon treatment by COX-2 inhibitors. Besides, the non-active celecoxib analog 2,5-dimethyl-celecoxib is able to protect from apoptosis as well. We demonstrate early prevention of the stress-induced apoptotic signaling, prior to Bax/Bak activation. This preventive effect fits with an impairment of the ability of chemotherapeutic agents to trigger apoptogenic stress. Accordingly, etoposide-induced DNA damage is strongly attenuated in the presence of COX-2 inhibitors. In contrast, COX-2 inhibitors do not exert any anti-apoptotic activity when cells are challenged with physiological stimuli (anti-Fas, TNFα or Trail) or with hydrogen peroxide, which do not require internalization and/or are not targeted by chemoresistance proteins. Altogether, our findings show a differential off-target anti-apoptotic effect of COX-2 inhibitors on intrinsic vs. extrinsic apoptosis at the very early steps of intracellular signaling, prior to commitment. The results imply that an exacerbation of the chemoresistance phenomena may be implicated.

Effect of celecoxib on survival in patients with advanced non-small cell lung cancer: a double blind randomised clinical phase III trial (CYCLUS study) by the Swedish Lung Cancer Study Group

BACKGROUND

Increased expression of cyclooxygenase-2 (COX-2) is common in non-small cell lung cancer (NSCLC) and has been associated with poor prognosis. Experimental and clinical phase II trials have indicated that the addition of the COX-2 inhibitor celecoxib to palliative chemotherapy might increase survival time in patients with advanced NSCLC.

METHODS

We performed a double-blind, placebo-controlled multicentre phase III trial at 13 centres in Sweden. Three hundred and nineteen patients with advanced NSCLC stage IIIB-IV and performance status 0-2 were randomised to receive celecoxib 400mg b.i.d. or placebo in addition to palliative chemotherapy. The primary objective was to compare overall survival. Other end-points were quality of life, progression-free survival, toxicity, cardiovascular events and biological markers. The trial is registered with ClinicalTrials.gov, No. NCT00300729.

FINDINGS

Three hundred and sixteen patients were included in the analysis, 158 in each treatment group. Median survival time was 8.5 months. There was no survival difference between the treatment arms. Small but not statistically significant differences in global quality of life and pain were seen favouring the celecoxib group. No increased incidence of cardiovascular events was observed in the celecoxib group.

INTERPRETATION

This study failed to demonstrate a survival benefit of the addition of celecoxib to palliative chemotherapy.

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.

Rosmanol potently induces apoptosis through both the mitochondrial apoptotic pathway and death receptor pathway in human colon adenocarcinoma COLO 205 cells

Rosemary (Rosmarinus officinalis), a culinary spice and medicinal herb, has been widely used in European folk medicine to treat numerous ailments. Many studies have shown that rosemary extracts play important roles in anti-inflammation, anti-tumor, and anti-proliferation in various in vitro and in vivo settings. The roles of tumor suppression of rosemary have been attributed to the major components, including carnosic acid, carnosol, and rosmarinic acid, rosmanol, and ursolic acid. This study was to explore the effect of rosmanol on the growth of COLO 205 human colorectal adenocarcinoma cells and to delineate the underlying mechanisms. When treated with 50 μM of rosmanol for 24h, COLO 205 cells displayed a strong apoptosis-inducing response with a 51% apoptotic ratio (IC(50) ∼42 μM). Rosmanol increased the expression of Fas and FasL, led to the cleavage and activation of pro-caspase-8 and Bid, and mobilized Bax from cytosol into mitochondria. The mutual activation between tBid and Bad decreased the mitochondrial membrane potential and released cytochrome c and apoptosis-inducing factor (AIF) to cytosol. In turn, cytochrome c induced the processing of pro-caspase-9 and pro-caspase-3, followed by the cleavage of poly-(ADP-ribose) polymerase (PARP) and DNA fragmentation factor (DFF-45). These results demonstrate that the rosmanol-induced apoptosis in COLO 205 cells is involvement of caspase activation and involving complicated regulation of both the mitochondrial apoptotic pathway and death receptor pathway.

Arachidonic acid actions on functional integrity and attenuation of the negative effects of palmitic acid in a clonal pancreatic β-cell line

Chronic exposure of pancreatic β-cells to saturated non-esterified fatty acids can lead to inhibition of insulin secretion and apoptosis. Several previous studies have demonstrated that saturated fatty acids such as PA (palmitic acid) are detrimental to β-cell function compared with unsaturated fatty acids. In the present study, we describe the effect of the polyunsaturated AA (arachidonic acid) on the function of the clonal pancreatic β-cell line BRIN-BD11 and demonstrate AA-dependent attenuation of PA effects. When added to β-cell incubations at 100 μM, AA can stimulate cell proliferation and chronic (24 h) basal insulin secretion. Microarray analysis and/or real-time PCR indicated significant AA-dependent up-regulation of genes involved in proliferation and fatty acid metabolism [e.g. Angptl (angiopoietin-like protein 4), Ech1 (peroxisomal Δ3,5,Δ2,4-dienoyl-CoA isomerase), Cox-1 (cyclo-oxygenase-1) and Cox-2, P<0.05]. Experiments using specific COX and LOX (lipoxygenase) inhibitors demonstrated the importance of COX-1 activity for acute (20 min) stimulation of insulin secretion, suggesting that AA metabolites may be responsible for the insulinotropic effects. Moreover, concomitant incubation of AA with PA dose-dependently attenuated the detrimental effects of the saturated fatty acid, so reducing apoptosis and decreasing parameters of oxidative stress [ROS (reactive oxygen species) and NO levels] while improving the GSH/GSSG ratio. AA decreased the protein expression of iNOS (inducible NO synthase), the p65 subunit of NF-κB (nuclear factor κB) and the p47 subunit of NADPH oxidase in PA-treated cells. These findings indicate that AA has an important regulatory and protective β-cell action, which may be beneficial to function and survival in the ‘lipotoxic’ environment commonly associated with Type 2 diabetes mellitus.

The ketogenic diet reverses gene expression patterns and reduces reactive oxygen species levels when used as an adjuvant therapy for glioma

BACKGROUND

Malignant brain tumors affect people of all ages and are the second leading cause of cancer deaths in children. While current treatments are effective and improve survival, there remains a substantial need for more efficacious therapeutic modalities. The ketogenic diet (KD) - a high-fat, low-carbohydrate treatment for medically refractory epilepsy - has been suggested as an alternative strategy to inhibit tumor growth by altering intrinsic metabolism, especially by inducing glycopenia.

METHODS

Here, we examined the effects of an experimental KD on a mouse model of glioma, and compared patterns of gene expression in tumors vs. normal brain from animals fed either a KD or a standard diet.

RESULTS

Animals received intracranial injections of bioluminescent GL261-luc cells and tumor growth was followed in vivo. KD treatment significantly reduced the rate of tumor growth and prolonged survival. Further, the KD reduced reactive oxygen species (ROS) production in tumor cells. Gene expression profiling demonstrated that the KD induces an overall reversion to expression patterns seen in non-tumor specimens. Notably, genes involved in modulating ROS levels and oxidative stress were altered, including those encoding cyclooxygenase 2, glutathione peroxidases 3 and 7, and periredoxin 4.

CONCLUSIONS

Our data demonstrate that the KD improves survivability in our mouse model of glioma, and suggests that the mechanisms accounting for this protective effect likely involve complex alterations in cellular metabolism beyond simply a reduction in glucose.

Targeting COX-2 expression by natural compounds: a promising alternative strategy to synthetic COX-2 inhibitors for cancer chemoprevention and therapy

Cyclooxygenase (COX)-2 is a pro-inflammatory immediate early response protein, chronically up-regulated in many pathological conditions. In autoimmune diseases, it is responsible for degenerative effects whereas in cancer, it correlates with poor prognosis. A constitutive expression of COX-2 is triggered since the earliest steps of carcinogenesis. Consequently, strategies aimed at inhibiting COX-2 enzymatic activity have been clinically applied for the treatment of autoimmune disorders; in addition, the same approaches are currently investigated for anti-cancer purposes. However, COX-2 protein inhibitors (i.e., NSAIDs and COXIBs) are not amenable to prolonged administration since they may cause severe side effects, and efforts are underway to identify alternative approaches for chemoprevention/therapy. COX-2 expression is a multi-step process, highly regulated at transcriptional and post-transcriptional levels. Defects in the modulation of one or both of these steps may be found in pathological conditions. Targeting COX-2 expression may therefore represent a promising strategy, by which the same preventive and therapeutic benefits may be gained while avoiding the severe side effects of COX-2 enzymatic inhibition. Naturally occurring compounds derived from plants/organisms represent a huge source of biologically active molecules, that remains largely unexplored. Derived from plants/organisms used in traditional forms of medicine or as dietary supplements, these compounds have been experimentally investigated for their anti-inflammatory and anti-cancer potential. In this review, we will analyze how natural compounds may modulate the multistep regulation of COX-2 gene expression and discuss their potential as a new generation of COX-2 targeting agents alternative to the synthetic COX-2 inhibitors.