Cyclo-oxygenase 2: a pharmacological target for the prevention of cancer

Biotinylated PAMAM G3 dendrimer conjugated with celecoxib and/or Fmoc-l-Leucine and its cytotoxicity for normal and cancer human cell lines

Tumors still remain one of the main causes of mortality due to the lack of effective anti-cancer therapy. Recently it has been shown, that overexpression of inducible cyclooxygenase-2 (COX-2) and decrease of peroxisome proliferator-activated receptor γ (PPARγ) expression accompany many malignances, therefore, it has been proposed, that COX-2 inhibitors and PPARγ agonists are potential candidates for anticancer therapy and their synergistic, antineoplastic action has been described. In the present study a COX-2 inhibitor (celecoxib) and/or PPARγ agonist (Fmoc-l-Leucine) were conjugated with the biotinylated G3 PAMAM dendrimer to form a three different constructs targeted to cells with increased biotin uptake. All conjugates were characterized by the NMR spectroscopy. Investigation of three types of human cells: normal skin fibroblasts (BJ), immortalized keratinocytes (HaCaT) and cancer lines: glioblastoma (U-118 MG) and squamous cell carcinoma (SCC-15) revealed similar biotin labeled ATTO590 accumulation (after 24 h), except for SCC-15 with significantly lower loading. Constitutive expression of COX-2 protein was confirmed in all tested cells with significantly higher levels (2-2.5 times) in both cancer lines. Comparison of cytotoxicity of the new synthetized dendrimers clearly documented the highest cytotoxicity of the G3^1B16C15L dendrimer conjugated with both drugs (1: 1) as compared with drugs alone and single conjugates. Additive effects of construct with both compounds were shown for fibroblasts and both cancer cell lines in the order BJ > U-118 MG > SCC-15 with IC₅₀ in the range: 0.69, 1.44 and 2.22 μM, respectively and lowest cytotoxicity in HaCaT cells (IC₅₀ = 2.88). Our results showed, that biotinylated G3 PAMAM dendrimers substituted with COX-2 inhibitor, celecoxib, and PPARγ agonist, Fmoc-l-Leucine (1:1) may be a good candidate for local therapy of glioblastoma but not a skin cancer. Since the effect of PPARγ agonists on COX-2 expression vary depending upon the cell type, specificity of used agonist and the presence of other environmental factors, it is necessary to carefully evaluate the response of chosen drugs on the target cells.

Epoxymicheliolide, a novelguaiane-type sesquiterpene lactone, inhibits NF‑κB/COX‑2 signaling pathways by targeting leucine 281 and leucine 25 in IKKβ in renal cell carcinoma

Parthenolide (PTL) is a sesquiterpene lactone compound obtained from Tanacetum parthenium (feverfew) and inhibits the activation of nuclear factor (NF)-κB. Epoxymicheliolide (EMCL) is a compound which is structurally related to PTL; however, EMCL is more stable under acidic and alkaline conditions. As a biologically active molecule, the detailed mechanism by which EMCL inhibits tumor activity remains to be elucidated. The present study evaluated the effect of EMCL on renal cell carcinoma (RCC) cells and identified the underlying mechanisms. It was found that treatment with EMCL significantly inhibited the proliferation of RCC cells in vitro and increased the induction of apoptosis by activating the mitochondria- and caspase-dependent pathway. Simultaneously, EMCL suppressed cell invasion and metastasis by inhibiting epithelial-mesenchymal transition, as observed in a microfluidic chip assay. Furthermore, using immunofluorescence analysis, an electrophoretic mobility shift assay and a dual-luciferase reporter assay, it was shown that treatment with EMCL significantly suppressed the expression of cyclooxygenase-2 by inhibiting the translocation of NF-κB p50/p65 and the activity of NF-κB. Collectively, the results indicated that EMCL suppressed tumor growth by inhibiting the activation of NF-κB and suggested that EMCL may be a novel anticancer agent in the treatment of RCC.

Cyclooxygenase-2 Expression Is a Predictive Marker for Late Recurrence in Colorectal Cancer

Introduction

Cyclooxygenase-2 (COX-2) expression is elevated in colorectal cancer (CRC). However, data about the relation between COX-2 expression and the impact on the biologic behavior of recurrent disease are inconclusive as yet. The aim of this study is to investigate the relationship between the status of COX-2 expression in the primary CRC and the characteristics of recurrence after curative resection of stage I to III CRC.

Materials and Methods

Ninety-eight patients with recurrence in 376 CRC patients, who underwent curative surgery between January 1991 and August 2001, were retrospectively assessed. Immunohistochemical staining, performed for the presence of COX-2 on tissue microarrays, was analyzed.

Results

Forty-six patients showed elevated COX-2 expression, and 52 patients did not. The mean time to recurrence was significantly longer in the positive group than in the negative group (34.1 months ± 30.0 versus 21.9 months ± 17.4; P = 0.019). Positive COX-2 expression was correlated with late recurrence (>3 years after surgery) [43.5% versus 13.5%; P = 0.001]. In multivariate analysis, COX-2 expression was an independent factor associated with late recurrence (OR 4.656; 95% CI, 1.696 to 12.779; P = 0.003). Recurrence pattern and postrecurrence survival were not different between the two groups.

Conclusions

Elevated COX-2 expression in itself is not a prognostic factor, but COX-2 expression in tumor tissue may be an independent predictive marker of late recurrence for patients with stage I to III CRC.

Development of Nanocochleates Containing Erlotinib HCl and Dexketoprofen Trometamol and Evaluation of In Vitro Characteristic Properties

Objectives

Erlotinib HCI is a tyrosine kinase receptor inhibitor and an anticancer agent that was first approved by the FDA in 2004 for treatment of non-small-cell lung cancer and pancreatic cancer. Dexketoprofen trometamol is a NSAID, but recent studies showed that dexketoprofen trometamol also had an effect in carcinoma due to its inhibitor effects on prostaglandins. The combination of dexketoprofen and anti-cancer agents reduces pain caused by cancer by diminishing the tumors pressure, which causes necrosis; it also lowers the poor prognosis of cancer. Combination therapy will make life easier for patients, considering drug administration and dosing. Nanocochleates are new drug delivery systems that have not been examined as much as liposomes, but they have more advantages than liposomes.

Materials and Methods

In this study, erlotinib HCl and dexketoprofen trometamol were loaded into nanocochleates with various formulations and particle sizes/distributions, polydispersity indexes, and zeta potential analyses were performed. Transmission electron microscopy imaging was performed with the obtained optimal formulation and drug-release studies using Franz diffusion cells were conducted.

Results

As a result, drug carrier systems with a particle size of 196.42-312.33 nm and zeta potential greater than 15 mV were produced. The highest encapsulation efficiency for the main active ingredient, erlotinib HCl, was obtained in the KOH-1B formulation with 86.22±1.45%.

Conclusion

This study showed that the drugs were successfully loaded into the nanocochleates and the nanocochleates actively released the drugs.

Voriconazole-induced photocarcinogenesis is promoted by aryl hydrocarbon receptor-dependent COX-2 upregulation

Voriconazole (VRCZ) induces the development of UV-associated skin cancers. The mechanism underlying the VRCZ-induced carcinogenesis has been largely unknown. Here, we showed that VRCZ metabolites plus UVA generated reactive oxygen species and resultant DNA damage of the epidermis, but did not induce substantial apoptosis in human keratinocytes (KCs). Furthermore, VRCZ per se stimulates aryl hydrocarbon receptor (AhR) and upregulates COX-2, which is a pivotal enzyme for the promotion of UV-associated tumors, in an AhR-ARNT dependent manner of the classical (genomic) pathway. Our findings suggest that the phototoxic moieties of VRCZ metabolites may participate in the initiation phase of VRCZ skin cancer, while VRCZ per se promotes the tumor development. Therefore, during VRCZ therapy, sun exposure protection is essential to prevent photocarcinogenesis caused by VRCZ metabolites plus UV. Chemoprevention with selective COX-2 inhibitors may be helpful to repress the development of skin cancers derived from DNA-damaged KCs.

ω-3 Long Chain Polyunsaturated Fatty Acids as Sensitizing Agents and Multidrug Resistance Revertants in Cancer Therapy

Chemotherapy efficacy is strictly limited by the resistance of cancer cells. The ω-3 long chain polyunsaturated fatty acids (ω-3 LCPUFAs) are considered chemosensitizing agents and revertants of multidrug resistance by pleiotropic, but not still well elucidated, mechanisms. Nowadays, it is accepted that alteration in gene expression, modulation of cellular proliferation and differentiation, induction of apoptosis, generation of reactive oxygen species, and lipid peroxidation are involved in ω-3 LCPUFA chemosensitizing effects. A crucial mechanism in the control of cell drug uptake and efflux is related to ω-3 LCPUFA influence on membrane lipid composition. The incorporation of docosahexaenoic acid in the lipid rafts produces significant changes in their physical-chemical properties affecting content and functions of transmembrane proteins, such as growth factors, receptors and ATP-binding cassette transporters. Of note, ω-3 LCPUFAs often alter the lipid compositions more in chemoresistant cells than in chemosensitive cells, suggesting a potential adjuvant role in the treatment of drug resistant cancers.

Effects of metamizole, MAA, and paracetamol on proliferation, apoptosis, and necrosis in the pancreatic cancer cell lines PaTu 8988 t and Panc-1

BACKGROUND

Adenocarcinoma of the pancreas is one of the most aggressive cancer diseases affecting the human body. Recent research has shown the importance of the perioperative phase in disease progression. Particularly during this vulnerable phase, substances such as metamizole and paracetamol are given as general anesthetics and postoperative analgesics. Therefore, the effects of metamizole and paracetamol on tumor progression should be investigated in more detail because the extent to which these substances influence the carcinogenesis of pancreatic carcinoma is still unclear. This study analyzed the influence of metamizole and its active metabolites MAA (4-N-methyl-aminoantipyrine) and paracetamol on the proliferation, apoptosis, and necrosis of the pancreatic cancer cell lines PaTu 8988t and Panc-1 in vitro.

METHODS

Cell proliferation was measured by means of the ELISA BrdU assay and the rate of apoptosis by flow cytometry using the Annexin V assay.

RESULTS

Metamizole and paracetamol significantly inhibited cell proliferation in pancreatic cancer cells. After the addition of metamizole to PaTu 8988t cells, the rate of apoptosis was reduced after 3 h of incubation but significantly increased after 9 h of incubation.

CONCLUSION

The oncogenic potential of pancreatic adenocarcinoma is mainly characterized by its extreme growth rate. Non-opioid analgesics such as metamizole and paracetamol are given as general anesthetics and postoperative analgesics. The combination of metamizole or paracetamol with cytotoxic therapeutic approaches may achieve synergistic effects. Further studies are necessary to identify the underlying mechanisms so that new therapeutic options may be developed for the treatment of this aggressive tumor.

Annonaceae: Breaking the Wall of Inflammation

Inventories of tropical forests have listed Annonaceae as one of the most diverse plant families. For centuries, it is employed in traditional medicines to cure various pathological conditions including snakebite, analgesic, astringent, diarrhea, dysentery, arthritis pain, rheumatism, neuralgia, and weight loss etc. Phytochemical analysis of Annonaceae family have reported the occurrence of alkaloids, flavonoids, triterpenes, diterpenes and diterpene flavone glycosides, sterols, lignans, and annonaceous acetogenin characteristically affiliated with Annonaceae sp. Numerous past studies have underlined the pleotropic pharmacological activities of the crude extracts and isolated compounds from Annonaceae species. This review is an effort to abridge the ethnobotany, morphology, phytochemistry, toxicity, and particularly focusing on the anti-inflammatory activity of the Annonaceae species.

Elevated COX-2 Expression Promotes Angiogenesis Through EGFR/p38-MAPK/Sp1-Dependent Signalling in Pancreatic Cancer

Cyclooxygenase-2 (COX-2) was stated to be overexpression in various human malignancies associating with angiogenesis, metastasis and chemoresistence. Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease displaying many of these characteristics. A common abnormality of PDAC is overexpression of specificity protein-1 (Sp1), which was said to correlate with malignant phenotypes of human cancers. Using RNA-seq data from The Cancer Genome Atlas (TCGA), we found that Sp1 expression was positively correlated with that of COX-2 in PDAC, and that the inhibition or overexpression of Sp1 in PDAC cells leads to decreased or elevated COX-2 expression. Luciferase reporter gene and chromatin immunoprecipitation (ChIP) assays revealed that elevated transcription of COX-2 requires Sp1 binding to sequence positions around -245/-240 of COX-2 promoter. Activated epidermal growth factor receptor (EGFR) and downstream p38 mitogen-activated protein kinase (p38-MAPK) were also profoundly altered in PDAC. The inhibition of EGFR/p38-MAPK signaling resulted in reduced Sp1 activation, decreased COX-2 and vascular endothelial growth factor (VEGF) expression. Thus, Sp1 could transcriptionally activate COX-2 expression in a process relies on activated EGFR/p38-MAPK signaling. Finally, we found that the inhibition of COX-2 leads to decreased angiogenesis in a process dependent on VEGF, which link COX-2 to angiogenesis in PDAC.

Melatonin Ameliorates The Production of COX-2, iNOS, and The Formation of 8-OHdG in Non-Targeted Lung Tissue after Pelvic Irradiation

In this study, we evaluated the bystander effect of radiation on the regulation of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), and 8-hydroxydeoxyguanosine (8-OHdG) in lung tissues of Sprague-Dawley rats with and without pre-administration of melatonin. A 2×2 cm² area of the pelvis of male Sprague-Dawley rats with and without pre-administration of melatonin (100 mg/kg) by oral and intraperitoneal injection was irradiated with a 3 Gy dose of 1.25 MeV γ-rays. Alterations in the levels of COX-2, iNOS, and 8-OHdG in the out-of-field lung areas of the animals were detected by enzyme immunoassay. The bystander effect significantly increased COX-2, iNOS, and 8-OHdG levels in non-targeted lung tissues (P<0.05). Melatonin ameliorated the bystander effect of radiation and significantly reduced the level of all examined biomarkers (P<0.05). The results indicated that the ameliorating effect of a pre-intraperitoneal (IP) injection of melatonin was noticeably greater compared to oral pre-administration. Our findings revealed that the bystander effect of radiation could induce oxidative DNA damage and increase the levels of imperative COX-2 and iNOS in non-targeted lung tissues. Interestingly, melatonin could modulate the indirect destructive effect of radiation and reduce DNA damage in non-targeted cells.

15-Hydroxyprostaglandin dehydrogenase as a marker in colon carcinogenesis: analysis of the prostaglandin pathway in human colonic tissue

Background/Aims

Cyclooxygenase-2 (COX-2), 15-hydroxyprostaglandin dehydrogenase (15-PGDH), and microsomal prostaglandin E synthase-1 (mPGEs-1) regulate prostaglandin E₂ (PGE₂) expression and are involved in colon carcinogenesis. We investigated the expression of PGE₂ and its regulating genes in sporadic human colon tumors and matched normal tissues.

Methods

Twenty colonic adenomas and 27 colonic adenocarcinomas were evaluated. COX-2 and 15-PGDH expression was quantified by real-time polymerase chain reaction. The expression of PGE₂ and mPGEs-1 was measured using enzyme-linked immunosorbent assay and Western blotting, respectively.

Results

The expression of COX-2, mPGEs-1, and PGE₂ did not differ between the adenomas and matched distant normal tissues. 15-PGDH expression was lower in adenomas than in the matched normal colonic tissues (P<0.001). In adenocarcinomas, mPGEs-1 and PGE₂ expression was significantly higher (P<0.001 and P=0.020, respectively), and COX-2 expression did not differ from that in normal tissues (P=0.207). 15-PGDH expression was significantly lower in the normal colonic mucosa from adenocarcinoma patients than in the normal mucosa from adenoma patients (P=0.018).

Conclusions

Early inactivation of 15-PGDH, followed by activation of COX-2 and mPGEs-1, contributes to PGE₂ production, leading to colon carcinogenesis. 15-PGDH might be a novel candidate marker for early detection of field defects in colon carcinogenesis.

Celecoxib and 2,5-dimethylcelecoxib inhibit intestinal cancer growth by suppressing the Wnt/β-catenin signaling pathway

We previously reported that celecoxib, a selective COX-2 inhibitor, strongly inhibited human colon cancer cell proliferation by suppressing the Wnt/β-catenin signaling pathway. 2,5-Dimethylcelecoxib (DM-celecoxib), a celecoxib analog that does not inhibit COX-2, has also been reported to have an antitumor effect. In the present study, we elucidated whether DM-celecoxib inhibits intestinal cancer growth, and its underlying mechanism of action. First, we compared the effect of DM-celecoxib with that of celecoxib on the human colon cancer cell lines HCT-116 and DLD-1. 2,5-Dimethylcelecoxib suppressed cell proliferation and inhibited T-cell factor 7-like 2 expression with almost the same strength as celecoxib. 2,5-Dimethylcelecoxib also inhibited the T-cell factor-dependent transcription activity and suppressed the expression of Wnt/β-catenin target gene products cyclin D1 and survivin. Subsequently, we compared the in vivo effects of celecoxib and DM-celecoxib using the Mutyh-/- mouse model, in which oxidative stress induces multiple intestinal carcinomas. Serum concentrations of orally administered celecoxib and DM-celecoxib elevated to the levels enough to suppress cancer cell proliferation. Repeated treatment with celecoxib and DM-celecoxib markedly reduced the number and size of the carcinomas without showing toxicity. These results suggest that the central mechanism for the anticancer effect of celecoxib derivatives is the suppression of the Wnt/β-catenin signaling pathway but not the inhibition of COX-2, and that DM-celecoxib might be a better lead compound candidate than celecoxib for the development of novel anticancer drugs.

The Role of NSAIDs in Breast Cancer Prevention and Relapse: Current Evidence and Future Perspectives

Aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) have received considerable interest as potential chemopreventive agents. The aim of this review is to summarize the accumulated knowledge on the effect of NSAIDs on breast cancer incidence and natural history, and the underlying pathophysiology. NSAIDs mainly block inflammation by inhibiting cyclooxygenase enzymes, leading to lower prostaglandin synthesis. The latter has been reported to affect breast cancer risk through hormonal and inflammation-related pathways. Intensity, dose, frequency, duration, and timing of administration may also be significant. There is currently enough evidence to support a role of NSAIDs in breast cancer prevention and relapse, which deserves further large-scale experimental and clinical investigation.

Transitional Cell Carcinoma in Fishing Cats (Prionailurus viverrinus): Pathology and Expression of Cyclooxygenase-1, -2, and p53

A high prevalence of urinary bladder transitional-cell carcinoma (TCC) has been noted in captive fishing cats ( Prionailurus viverrinus). Of the 91 adult deaths between 1995 and 2004, 12 (13%) were attributed to TCC. To help elucidate mechanisms of carcinogenesis, archival sections of urinary bladder from 14 fishing cats were examined histologically and immunohistochemically for p53, cyclooxygenase (COX)-1, and COX-2 expression. Ten cats had TCC, and 4 were unaffected. The average age at death was 10.8 years in affected individuals and 10.5 years in unaffected individuals. There was no sex predilection. Fishing cat TCCs were characterized histologically as papillary and infiltrating ( n = 6), nonpapillary and infiltrating ( n = 3), or carcinoma in situ ( n = 1). Glandular and squamous metaplasia, necrosis, and lymphatic invasion were prominent histologic features. Two individuals had documented metastasis. p53 nuclear immunolabeling was detected in 4/10 (40%) TCCs. In two cases, immunolabeling was limited to less than 10% of the neoplastic cellular population and was comparable to staining of normal fishing cat bladder. Therefore, p53 gene mutation did not appear to be an essential component of TCC carcinogenesis in examined fishing cats. COX-1 immunohistochemistry was negative in all cases. All TCCs had some degree of COX-2 cytoplasmic immunolabeling, which was exclusively within the invasive portions of the neoplasms. Papillary portions were uniformly negative. COX-2 overexpression was a prominent feature in the majority of the examined fishing cat TCCs, suggesting that COX-2-mediated mechanisms of carcinogenesis are important in this species and that COX-inhibiting drugs may be of therapeutic benefit.

Anti-fibro-hepatocarcinogenic Chinese herbal medicines: A mechanistic overview

Chinese herbal medicine (CHM) is an integral component of complementary/alternative medicine and it is increasingly becoming the preferred therapeutic modality for the treatment of liver fibrosis and hepatocellular carcinoma (HCC) worldwide. Accordingly, the World Health Organization (WHO) has attested to the popularity and efficacy of indigenous herbal therapies including CHM as a first line of treatment for some diseases including liver disorders. However, the WHO and drug discovery experts have always recommended that use of indigenous herbal remedies must go hand-in-hand with the requisite mechanistic elucidation so as to constitute a system of verification of efficacy within the ethnobotanical context of use. Although many CHM experts have advanced knowledge on CHM, nonetheless, more enlightenment is needed, particularly mechanisms of action of CHMs on fibro-hepato-carcinogenesis. We, herein, provide in-depth mechanisms of the action of CHMs which have demonstrated anti-fibro-hepatocarcinogenic effects, in pre-clinical and clinical studies as published in PubMed and other major scientific databases. Specifically, the review brings out the important signaling pathways, and their downstream targets which are modulated at multi-level by various anti-fibro-hepatocarcinogenic CHMs.

Repositioning of drugs for intervention in tumor progression and metastasis: Old drugs for new targets

The increasing unraveling of the molecular basis of cancer offers manifold novel options for intervention strategies. However, the discovery and development of new drugs for potential clinical applications is a tremendously time-consuming and costly process. Translating a novel lead candidate compound into an approved clinical drug takes often more than a decade, and the success rate is very low due to versatile efforts including defining its pharmacokinetics, pharmacodynamics, side effects as well as lack of sufficient efficacy. Thus, strategies are needed to minimize time and costs, while maximizing success rates. A very attractive strategy for novel cancer therapeutic options is the repositioning of already approved drugs. These medicines, approved for the treatment of non-malignant disorders, have already passed some early costs and time, have been tested in humans and are ready for clinical trials as anti-cancer drugs. Here we discuss the repositioning of nonsteroidal anti-inflammatory drugs (NSAID), statins, anti-psychotic drugs, anti-helminthic drugs and vitamin D as anti-tumor agents. We focus on their novel actions and potential for inhibition of cancer growth and metastasis by interfering with target molecules and pathways, which drive these malignant processes. Furthermore, important pre-clinical and clinical data are reviewed herein, which elucidate their therapeutic mechanisms which enable their repositioning for cancer therapy and disruption of metastasis.

Synthesis of Novel Substituted Thiourea and Benzimidazole Derivatives Containing a Pyrazolone Ring as Anti-Inflammatory Agents

Two series of new 1-(alkyl/aryl)-3-{2-[(5-oxo-4,5-dihydro-1H-pyrazol-3-yl)amino]phenyl}thioureas 2a-h and 5-[2-(substituted amino)-1H-benzimidazol-1-yl]-4H-pyrazol-3-ols 3a-i were designed and synthesized as anti-inflammatory agents. The cyclooxygenase inhibitory activity of the newly synthesized compounds was investigated. All the compounds showed non-selective inhibition of COX-1 and COX-2 enzymes which was consistent with their docking results. Compounds 2c, 2f, 2g, 3b, and 3g that showed the highest COX-2 inhibitory activity were selected for further in vivo testing as anti-inflammatory agents using diclofenac as a reference drug. Two of the test compounds (2c and 3b) showed potent anti-inflammatory activity comparable to that of diclofenac with lower ulcerogenic effect relative to indomethacin. SAR study of the two series as cyclooxygenase inhibitors and anti-inflammatory agents was also provided.

COX inhibitors: a patent review (2011 - 2014)

INTRODUCTION

The COX enzymes play a central role in the biosynthetic pathway of important biological mediators called prostanoids. Differences in regulation of gene expression, stability of transcripts and proteins determine the different biological functions of COX-1 and COX-2. While the COX-1 gene has been considered to be a 'housekeeping' gene expressed in many tissues and cells, COX-2 gene is upregulated during inflammation, hypoxia and in many cancers.

AREAS COVERED

The first part of this review provides a survey of the development of both modified traditional NSAIDs (tNSAIDs) and COX inhibitors (coxibs) with reduced side effects for the treatment of inflammation and cancer. The second part deals with patents reporting several dual inhibitors characterized by the conjugation of a COX-inhibitor scaffold to a molecule able to modulate a different target. Finally, two patents on novel COX inhibitor scaffolds are reported.

EXPERT OPINION

The most interesting branch of research concerns the conjugation of a COX-inhibitor scaffold to a molecule able to modulate a different target, in order to either enhance anti-inflammatory activity or to act as a dual inhibitor. Among the described compounds, selenium-containing coxibs inhibiting COX-2 and Akt, in addition to the multi-target biphenyl derivatives as dual inhibitors of COX and fatty acid amide hydrolase, are the most promising ones.

Therapeutic potential of cyclooxygenase-3 inhibitors in the management of glioblastoma

In this study we investigated the expression of COX-1, COX-2 and COX-3 mRNA in C6 glioblastoma and normal brain tissues and the effects of acetaminophen, indomethacin or metamizole treatments on the development of C6 glioblastoma in relation with COX inhibition. Glioblastoma cells were inoculated intracerebrally into frontal lobe of adult male Wistar albino rats. 10 days after inoculation, rats were treated with 150 mg/kg acetaminophen, 10 mg/kg indomethacin or 150 mg/kg metamizole. The tumor size was measured histologically and total RNA was isolated from tumor or normal brain tissue and mRNA levels of COX isoforms were determined by qRT-PCR. Our results showed the presence of COX-1, COX-2 and COX-3 expressions in both C6 glioblastoma and normal brain tissues. In tumor tissues COX-3 expression was significantly higher than normal brain tissue (p < 0.05) while there was no significant difference in COX-1 and COX-2 expressions. Acetaminophen and indomethacin decreased the tumor size by 71 and 43 % by inhibiting COX-3 mRNA expression around 87 and 91 % respectively. For the first time our study proposes a possible relationship between COX-3 mRNA expression and C6 glioblastoma development. We also suggested that the inhibition of COX-3 enzyme may be responsible for decrease in tumor size in part, the mechanism by which acetaminophen and indomethacin decreased rat C6 glioblastoma growth. However, the molecular events responsible for COX-3 effects on tumor development are still unresolved as these drugs exert their anti-cancer effect via both COX-3 dependent and independent mechanisms.

Obesity and cancer: local and systemic mechanisms

Obesity is a leading modifiable risk factor for the development of several epithelial malignancies. In addition to increasing risk, obesity also confers worse prognosis for many cancers. Obesity represents an overall state of energy imbalance frequently associated with systemic effects including insulin resistance, altered hormone signaling, and high circulating levels of proinflammatory mediators. In addition to its systemic effects, obesity causes subclinical white adipose inflammation including increased tissue levels of proinflammatory mediators. Both local and systemic effects are likely to contribute to the development and progression of cancer. An understanding of the interplay between local and systemic alterations involved in the obesity-cancer link provides the basis for developing interventions aimed at mitigating the protumorigenic effects.

Targeting obesity-related adipose tissue dysfunction to prevent cancer development and progression

The incidence of obesity, a leading modifiable risk factor for common solid tumors, is increasing. Effective interventions are needed to minimize the public health implications of obesity. Although the mechanisms linking increased adiposity to malignancy are incompletely understood, growing evidence points to complex interactions among multiple systemic and tissue-specific pathways including inflamed white adipose tissue. The metabolic and inflammatory consequences of white adipose tissue dysfunction collectively provide a plausible explanation for the link between overweight/obesity and carcinogenesis. Gaining a better understanding of these underlying molecular pathways and developing risk assessment tools that identify at-risk populations will be critical in implementing effective and novel cancer prevention and management strategies.

Protective effect of (±)α-tocopherol on brominated diphenyl ether-47-stimulated prostaglandin pathways in human extravillous trophoblasts in vitro

Brominated diphenyl ether (BDE)-47 is a prevalent flame retardant chemical found in human tissues and is linked to adverse pregnancy outcomes in humans. Because dysregulation of the prostaglandin pathway is implicated in adverse pregnancy outcomes, the present study investigates BDE-47 induction of prostaglandin synthesis in a human extravillous trophoblast cell line, HTR-8/SVneo, examining the hypothesis that BDE-47 increases generation of reactive oxygen species (ROS) to stimulate the prostaglandin response. Treatment with 20 μM BDE-47 significantly increased mRNA expression of prostaglandin-endoperoxide synthase 2 (PTGS2) at 4, 12 and 24 h, and 24-h treatment significantly increased cyclooxygenase (COX)-2 cellular protein expression and prostaglandin E2 (PGE2) concentration in culture medium. The BDE-47-stimulated PGE2 release was inhibited by the COX inhibitors indomethacin and NS398, implicating COX activity. Exposure to 20 μM BDE-47 significantly increased ROS generation as measured by carboxydichlorofluorescein fluorescence, and this response was blocked by cotreatment with the peroxyl radical scavenger (±)-α-tocopherol. (±)-α-Tocopherol cotreatment suppressed BDE-47-stimulated increases of PGE2 release without significant effects on COX-2 mRNA and protein expression, implicating a role for ROS in post-translational regulation of COX activity. Because prostaglandins regulate trophoblast functions necessary for placentation and pregnancy, further investigation is warranted of BDE-47 impacts on trophoblast responses.

Berberis libanotica extract targets NF-κB/COX-2, PI3K/Akt and mitochondrial/caspase signalling to induce human erythroleukemia cell apoptosis

The aim of this study was to describe and understand the relationship between cyclooxygenase-2 (COX-2) expression and apoptosis rate in erythroleukemia cells after apoptosis induction by Berberis libanotica (Bl) extract. To achieve this goal we used erythroleukemia cell lines expressing COX‑2 (HEL cell line) or not (K562 cell line). Moreover, we made use of COX‑2 cDNA to overexpress COX‑2 in K562 cells. In light of the reported chemopreventive and chemosensitive effects of natural products on various tumor cells and animal models, we postulated that our Bl extract may mediate their effects through apoptosis induction with suppression of cell survival pathways. Our study is the first report on the specific examination of intrinsic apoptosis and Akt/NF-κB/COX‑2 pathways in human erythroleukemia cells upon Bl extract exposure. Even if Bl extract induced apoptosis of three human erythroleukemia cell lines, a dominant effect of Bl extract treatment on K562 cells was observed resulting in activation of the late markers of apoptosis with caspase-3 activation, PARP cleavage and DNA fragmentation. Whereas, we showed that Bl extract reduced significantly expression of COX‑2 by a dose-dependent manner in HEL and K562 (COX‑2+) cells. Furthermore, in regard to our results, it is clear that the simultaneous inhibition of Akt and NF-κB signalling can significantly contribute to the anticancer effects of Bl extract in human erythroleukemia cells. We observed that the Bl extract is clearly more active than the berberine alone on the induction of DNA fragmentation in human erythro-leukemia cells.

FK-3000 isolated from Stephania delavayi Diels. inhibits MDA-MB-231 cell proliferation by decreasing NF-κB phosphorylation and COX-2 expression

The World Health Organization (WHO) has reported that cancer is one of the most prevalent diseases and a leading cause of death worldwide. Many anticancer drug development studies have been pursued over the last few decades and several viable drugs have been discovered, such as paclitaxel, topotecan and irinotecan. Previously, our research group uncovered the cytocidal and cytostatic effects of the plant Stephania delavayi Diels. In this study, we determined the active chemical to be 6,7-di-O-acetylsinococuline (FK-3000). The FK-3000 half maximal inhibitory concentration (IC50) in MDA-MB-231 breast carcinoma cells at 48 h was 0.52 µg/ml and it induced apoptosis in a dose- and time-dependent manner. FK-3000 suppressed NF-κB nuclear translocation, decreased NF-κB phosphorylation, and decreased COX-2 protein expression. MDA-MB-231 xenografted mice were treated with FK-3000, Taxol, or their combination for 21 days. The tumor size was smallest in the co-treatment group, indicating that FK-3000 may have a synergistic effect with Taxol. FK-3000 treatment showed no adverse effects on blood cell counts, serum protein levels, or pathology. These studies demonstrate that FK-3000, isolated from S. delavayi Diels., is a promising, pathway-specific anticancer agent that exhibits low toxicity.

Enhancement of Cisplatin sensitivity in human cervical cancer: epigallocatechin-3-gallate

Cisplatin is one of the effective chemotherapeutics in the treatment of several types of cancers. However, in addition to the efforts against to its toxicity, the amelioration of cisplatin sensitivity is an important point in treatment of cervical cancer. To do so, additional substances such as epigallocatechin gallate (EGCG), a polyphenol in green tea, have been used in combination with chemotherapeutics. We aimed to investigate the possible molecular pathways to potentiate cervical cancer cell (HeLa) growth inhibition by combination therapy of cisplatin and EGCG. HeLa cells were treated with EGCG (25 μM), cisplatin (250 nM), and their combination for 24 h. Cell viability was determined by MTS Assay. We analyzed the expressions of NF-κB p65, COX-2, Nrf2, HO-1, p-mTOR, p-p70S6K1, p-4E-BP1, and p-Akt by Western blot analysis. Herein, we have demonstrated that EGCG works synergistic with cisplatin in inhibiting growth of cervical cancer cells. EGCG improved efficacy of cisplatin treatment in HeLa cells by regulating NFκB p65, COX-2, p-Akt, and p-mTOR pathways, whereas it increased the expression levels of Nrf2/HO-1 in combined therapy. Our observations revealed that EGCG increases the sensitization of cisplatin to cervical cancer cells by inhibiting cell survival and inducing apoptosis.

[Interaction of anesthetics and analgesics with tumor cells]

The results of preclinical and clinical studies indicate that the perioperative period is a vulnerable period for cancer progression and metastasis. The risk of cancer cell dissemination is enhanced by the combination of surgical manipulation and perioperative immunosuppression. Whether the oncological outcome of cancer patients can be influenced by the choice of anesthetic techniques is still a matter of debate. This review summarizes the molecular characteristics of cancer and interaction of anesthetic and analgesic drugs with cancer cells.

Anti-inflammatory activity of grains of paradise (Aframomum melegueta Schum) extract

The ethanolic extract of grains of paradise (Aframomum melegueta Schum, Zingiberaceae) has been evaluated for inhibitory activity on cyclooxygenase-2 (COX-2) enzyme, in vivo for the anti-inflammatory activity and expression of several pro-inflammatory genes. Bioactivity-guided fractionation showed that the most active COX-2 inhibitory compound in the extract was [6]-paradol. [6]-Shogaol, another compound from the extract, was the most active inhibitory compound in pro-inflammatory gene expression assays. In a rat paw edema model, the whole extract reduced inflammation by 49% at 1000 mg/kg. Major gingerols from the extract [6]-paradol, [6]-gingerol, and [6]-shogaol reduced inflammation by 20, 25 and 38%. respectively when administered individually at a dose of 150 mg/kg. [6]-Shogaol efficacy was at the level of aspirin, used as a positive control. Grains of paradise extract has demonstrated an anti-inflammatory activity, which is in part due to the inhibition of COX-2 enzyme activity and expression of pro-inflammatory genes.

Aspirin may prevent cholangiocarcinoma: a case-control study from the United kingdom

BACKGROUND

The proliferation of cholangiocarcinoma cells is suppressed in cell culture by nonsteroidal antiinflammatory drugs (NSAIDs) through the inhibition of cyclo-oxygenase-2 enzyme and also by statins which decrease the production of mediators of the cell cycle.

AIMS

To investigate whether there is an inverse association between NSAIDs, including aspirin, and the development of cholangiocarcinoma and, for the first time in a Western population, between statin use and the development of cholangiocarcinoma.

METHODS

This epidemiological study had a case-control design in which cases of cholangiocarcinoma diagnosed in Norwich between 2004 and 2010 and in Leicester in 2007 were identified from clinical databases. Controls were patients with basal cell carcinomas treated in the respective dermatology departments. The case notes of all subjects were reviewed to confirm diagnoses and obtain information on medication use. The data were analyzed using unconditional logistic regression to calculate odds ratios (OR) with 95 % confidence intervals (CI).

RESULTS

In total, 81 cases of cholangiocarcinoma and 275 controls were identified. For all cases there was radiological evidence of cancer and 86 % of the cases involved the extrahepatic biliary system. Aspirin use was inversely associated with the development of cholangiocarcinoma (OR 0.45, 95 % CI 0.22-0.92), but there were no significant associations between the development of cholangiocarcinoma and NSAIDs (OR 0.39; 95 % CI 0.11-1.42) or statins (OR 0.58; 95 % CI 0.28-1.19).

CONCLUSIONS

The epidemiological data from this study support the biological evidence for aspirin having a protective effect against the development of cholangiocarcinoma. Aspirin use should be measured in future etiological studies and assessed as a chemoprevention agent in those at high risk of developing this type of cancer.

A review of the application of inflammatory biomarkers in epidemiologic cancer research

Inflammation is a facilitating process for multiple cancer types. It is believed to affect cancer development and progression through several etiologic pathways, including increased levels of DNA adduct formation, increased angiogenesis, and altered antiapoptotic signaling. This review highlights the application of inflammatory biomarkers in epidemiologic studies and discusses the various cellular mediators of inflammation characterizing the innate immune system response to infection and chronic insult from environmental factors. Included is a review of six classes of inflammation-related biomarkers: cytokines/chemokines, immune-related effectors, acute-phase proteins, reactive oxygen and nitrogen species, prostaglandins and cyclooxygenase-related factors, and mediators such as transcription factors and growth factors. For each of these biomarkers, we provide a brief overview of the etiologic role in the inflammation response and how they have been related to cancer etiology and progression within the literature. We provide a discussion of the common techniques available for quantification of each marker, including strengths, weaknesses, and potential pitfalls. Subsequently, we highlight a few under-studied measures to characterize the inflammatory response and their potential utility in epidemiologic studies of cancer. Finally, we suggest integrative methods for future studies to apply multifaceted approaches to examine the relationship between inflammatory markers and their roles in cancer development.

Intraperitoneal oxidative stress in rabbits with papillomavirus-associated head and neck cancer induces tumoricidal immune response that is adoptively transferable

PURPOSE

How tumors evade or suppress immune surveillance is a key question in cancer research, and overcoming immune escape is a major goal for lengthening remission after cancer treatment. Here, we used the papillomavirus-associated rabbit auricular VX2 carcinoma, a model for studying human head and neck cancer, to reveal the mechanisms underlying the antitumorigenic effects of intraperitoneal oxidative stress following O3/O2-pneumoperitoneum (O3/O2-PP) treatment.

EXPERIMENTAL DESIGN

Solid auricular VX2 tumors were induced in immune-competent adult New Zealand White Rabbits. Animals were O3/O2-PP- or sham-treated, after which they underwent tumor ablation upon reaching no-go criteria. CD3(+) tumor-infiltrating lymphocytes (TIL) were evaluated by immunohistochemistry, and expression levels of 84 immune response genes were measured by quantitative real-time PCR. Adoptive transfer of peripheral blood leukocytes (PBL)-derived from animals with tumor regression-into control animals with progressing tumors was implemented to assess acquired tumor resistance functionally.

RESULTS

Auricular VX2 tumors regressing after O3/O2-PP treatment exhibited increased levels of CD3(+) TILs; they also exhibited enhanced expression of genes that encode receptors involved in pattern recognition, molecules that are required for antigen presentation and T cell activation, and inflammatory mediators. Adoptive cell transfer of PBLs from donor rabbits with regressing tumors to recipient rabbits with newly implanted VX2 carcinoma resulted in acquired tumor resistance of the host and tumor regression.

CONCLUSION

Intraperitoneal oxidative stress effectively converts the immune response against the papillomavirus-associated rabbit VX2 carcinoma from tumor permissive to tumoricidal and leads to a sustainable, adoptively transferable oncolytic immune response.

Corticotropin-releasing hormone receptors mediate apoptosis via cytosolic calcium-dependent phospholipase A₂ and migration in prostate cancer cell RM-1

Peripheral corticotropin-releasing hormone receptors (CRHRs) are G protein-coupled receptors that play different roles depending on tissue types. Previously, we discovered the mechanism of CRHR-mediated apoptosis of mouse prostate cancer cell line (RM-1) to be a change of Bcl-2:Bax ratio, and CRH was found to inhibit transforming growth factor β migration of breast cancer cells via CRHRs. In the present study, we investigated cytosolic calcium-dependent phospholipase A2 (cPLA2) bridging CRHR activations and Bcl-2:Bax ratio and the effect of CRHR activation on cell migration. Silencing of cPLA2 attenuated a CRHR1 agonist, CRH-induced apoptosis, and the decrease of the Bcl-2:Bax ratio, whereas silencing of cPLA2 aggravated CRHR2 agonist, Urocortin 2 (Ucn2)-inhibited apoptosis, and the increase of the Bcl-2:Bax ratio. CRH in a time- and concentration-dependent manner increased cPLA2 expression mainly through interleukin 1β (IL1β) upregulation. Ucn2 decreased cPLA2 expression through neither tumor necrosis factor α nor IL1β. CRH-suppressed decay of cPLA2 mRNA and Ucn2 merely suppressed its production. Overexpression of CRHR1 or CRHR2 in HEK293 cells correspondingly upregulated or downregulated cPLA2 expression after CRH or Ucn2 stimulation respectively. In addition, both CRH and Ucn2 induced migration of RM-1 cells. Our observation not only established a relationship between CRHRs and cell migration but also for the first time, to our knowledge, demonstrated that cPLA2 participates in CRHR1-induced apoptosis and CRHR2-inhibited apoptosis.

Quantitative measurement of m-RNA levels to assess expression of cyclooxygenase-II, inducible nitric oxide synthase and 12-lipoxygenase genes in middle ear cholesteatoma

To assess expression of three main inflammatory genes, COX-II, ALOX-12 and i-NOS, quantitatively at transcriptional level in cholesteatoma matrix tissue. Ten patients who have chronic otitis media with primary acquired cholesteatoma were included in this study. Tissue samples obtained from cholesteatoma matrix and external ear canal skin (control tissue). Expression of the targeted genes (COX-II, i-NOS and LOX-12) was assessed using real-time quantitative polymerase chain reaction (RT-PCR) technique. The amount of COX2 mRNA was significantly higher in cholesteatoma matrix at transcriptional level (p = 0.038). There was no statistically significant difference regarding expression of iNOS and LOX12 mRNA levels (p > 0.05). There is a significant overexpression of the mRNA of COX-II in cholesteatoma matrix, which indicates a difference between the normal skin and cholesteatoma matrix at molecular level. COX-II gene overexpression seems to be associated with pathogenesis of cholesteatoma. This molecular change is similar to the molecular abnormalities observed in some benign and malignant neoplasms. Invasive and locally destructive nature of cholesteatoma may be due to COX-II overexpression. Absence of an increase in the gene expressions of i-NOS and LOX-12 in cholesteatoma matrix suggests that these mediators may not be related with the pathogenesis and evolution of cholesteatoma.

Microfluidic assembly of monodisperse multistage pH-responsive polymer/porous silicon composites for precisely controlled multi-drug delivery

We report an advanced drug delivery platform for combination chemotherapy by concurrently incorporating two different drugs into microcompoistes with ratiometric control over the loading degree. Atorvastatin and celecoxib were selected as model drugs due to their different physicochemical properties and synergetic effect on colorectal cancer prevention and inhibition. To be effective in colorectal cancer prevention and inhibition, the produced microcomposite contained hypromellose acetate succinate, which is insoluble in acidic conditions but highly dissolving at neutral or alkaline pH conditions. Taking advantage of the large pore volume of porous silicon (PSi), atorvastatin was firstly loaded into the PSi matrix, and then encapsulated into the pH-responsive polymer microparticles containing celecoxib by microfluidics in order to obtain multi-drug loaded polymer/PSi microcomposites. The prepared microcomposites showed monodisperse size distribution, multistage pH-response, precise ratiometric controlled loading degree towards the simultaneously loaded drug molecules, and tailored release kinetics of the loaded cargos. This attractive microcomposite platform protects the payloads from being released at low pH-values, and enhances their release at higher pH-values, which can be further used for colon cancer prevention and treatment. Overall, the pH-responsive polymer/PSi-based microcomposite can be used as a universal platform for the delivery of different drug molecules for combination therapy.

Restoration of E-cadherin expression by selective Cox-2 inhibition and the clinical relevance of the epithelial-to-mesenchymal transition in head and neck squamous cell carcinoma

BACKGROUND

The epithelial-to-mesenchymal transition (EMT) accompanied by the downregulation of E-cadherin has been thought to promote metastasis. Cyclooxygenase-2 (Cox-2) is presumed to contribute to cancer progression through its multifaceted function, and recently its inverse relationship with E-cadherin was suggested. The aim of the present study was to investigate whether selective Cox-2 inhibitors restore the expression of E-cadherin in head and neck squamous cell carcinoma (HNSCC) cells, and to examine the possible correlations of the expression levels of EMT-related molecules with clinicopathological factors in HNSCC.

METHODS

We used quantitative real-time PCR to examine the effects of three selective Cox-2 inhibitors, i.e., celecoxib, NS-398, and SC-791 on the gene expressions of E-cadherin (CDH-1) and its transcriptional repressors (SIP1, Snail, Twist) in the human HNSCC cell lines HSC-2 and HSC-4. To evaluate the changes in E-cadherin expression on the cell surface, we used a flowcytometer and immunofluorescent staining in addition to Western blotting. We evaluated and statistically analyzed the clinicopathological factors and mRNA expressions of Cox-2, CDH-1 and its repressors in surgical specimens of 40 patients with tongue squamous cell carcinoma (TSCC).

RESULTS

The selective Cox-2 inhibitors upregulated the E-cadherin expression on the cell surface of the HNSCC cells through the downregulation of its transcriptional repressors. The extent of this effect depended on the baseline expression levels of both E-cadherin and Cox-2 in each cell line. A univariate analysis showed that higher Cox-2 mRNA expression (p = 0.037), lower CDH-1 mRNA expression (p = 0.020), and advanced T-classification (p = 0.036) were significantly correlated with lymph node metastasis in TSCC. A multivariate logistic regression revealed that lower CDH-1 mRNA expression was the independent risk factor affecting lymph node metastasis (p = 0.041).

CONCLUSIONS

These findings suggest that the appropriately selective administration of certain Cox-2 inhibitors may have an anti-metastatic effect through suppression of the EMT by restoring E-cadherin expression. In addition, the downregulation of CDH-1 resulting from the EMT may be closely involved in lymph node metastasis in TSCC.

2-(2-Arylphenyl)benzoxazole As a Novel Anti-Inflammatory Scaffold: Synthesis and Biological Evaluation

The 2-(2-arylphenyl)benzoxazole moiety has been found to be a new and selective ligand for the enzyme cyclooxygenase-2 (COX-2). The 2-(2-arylphenyl)benzoxazoles 3a-m have been synthesized by Suzuki reaction of 2-(2-bromophenyl)benzoxazole. Further synthetic manipulation of 3f and 3i led to 3o and 3n, respectively. The compounds 3g, 3n, and 3o selectively inhibited COX-2 with selectivity index of 3n much better than that of the COX-2 selective NSAID celecoxib. The in vivo anti-inflammatory potency of 3g and 3n is comparable to that of celecoxib and the nonselective NSAID diclofenac at two different doses, and 3o showed better potency compared to these clinically used NSAIDs.

Upregulation of prostaglandin receptor EP1 expression involves its association with cyclooxygenase-2

While many signals cause upregulation of the pro-inflammatory enzyme cyclooxygenase -2 (COX-2), much less is known about mechanisms that actively downregulate its expression. We have recently shown that the prostaglandin EP₁ receptor reduces the expression of COX-2 in a pathway that facilitates its ubiquitination and degradation via the 26S proteasome. Here we show that an elevation of COX-2 intracellular levels causes an increase in the endogenous expression of prostaglandin EP₁. The increase in EP₁ levels does not occur at the transcriptional level, but is rather associated with complex formation between the receptor and COX-2, which occurs both in vitro and in mammalian tissues. The EP₁-COX-2 complex is disrupted following binding of arachidonic acid to COX-2 and accompanied by a parallel reduction in EP₁ levels. We propose that a transient interaction between COX-2 and EP₁ constitutes a feedback loop whereby an increase in COX-2 expression elevates EP₁, which ultimately acts to downregulate COX-2 by expediting its proteasomal degradation. Such a post translational mechanism may serve to control both the ligand-generating system of COX-2 and its reception system.

5-methoxyindole metabolites of L-tryptophan: control of COX-2 expression, inflammation and tumorigenesis

Cyclooxygenase-2(COX-2) overexpression promotes inflammation and tumorigenesis. COX-2 expression in response to diverse stimuli is tightly controlled to avoid persistent overexpression. 5-methoxyindole metabolites of L-tryptophan represent a new class of compounds that control COX-2 expression at the transcriptional level. Two of the metabolites, the newly discovered 5-methoxytryptophan (5-MTP, also known as cytoguardin) and N-acetyl 5-methoxytryptamine (melatonin) are the focus of this review. 5-MTP is produced by mesenchymal cells such as fibroblasts via 5-hydroxytryptophan (5-HTP). It inhibits COX-2 transcriptional activation induced by diverse proinflammatory and mitogenic factors. Cancer cells are deficient in cytoguardin production which contributes to COX-2 overexpression. Fibroblast-generated 5-MTP is capable of restoring the control of COX-2 overexpression in cancer cells. 5-MTP blocks cancer cell migration and invasion in vitro and inhibits tumor growth and cancer metastasis in a xenograft model. Melatonin possesses similar COX-2 suppressing and anti-cancer properties albeit at supra-pharmacological concentrations. By contrast, 5-hydroxyindole metabolites of L-tryptophan such as 5-hydroxytryptamine (serotonin), 5-hydroxytryptophol and other serotonin catabolites do not control COX-2 expression. 5-hydroxytryptophan inhibits COX-2 expression through conversion to 5-MTP. The physiological relevance of 5-MTP as an endogenous regulator of inflammation and cancer metastasis remains to be investigated. On the other hand, 5-methoxyindole metabolites of tryptophan are valuable lead compounds for development of new anti-inflammatory drugs and cancer chemoprevention.

Lack of association between cyclooxygenase 2-765G/C gene polymorphism and breast cancer risk in Ahvaz, west-south Iran

Cyclooxygenases are key enzymes in conversion of arachidonic acid into prostaglandin H2. Cyclooxygenase-2 (COX-2) increases prostaglandins in neoplastic tissue. COX-2 has important roles in cell proliferation cancers, angiogenesis, and alzheimer. COX-2 is up-regulated in several types of cancer, and it is hypothesized that COX-2 expression may be genetically influenced. Our main objective was to evaluated the association of polymorphism COX-2 with risk of breast cancer in khouzestan province, and the second objective of the study was to evaluate the association with biochemistry parameters. This study consisting of 150 patients with breast cancer and 120 normal DNA was extracted from the white blood cells. Polymorphism cox2 gene was detected by polymerase chain reaction according to the standard methods. The profile lipids and estrogen were measured in two groups by standard methods. Chi square analysis showed that there was no association between breast cancer risk and COX-2 -765G>C genotype and alleles. Also, no association were observed between -765G>C polymorphism and biochemistry parameters. A multiple logistic regression model with cox2 genotypes and LDL and HDL as covariates revealed that there is no significant association between cox2 genotypes and risk of breast cancer, but higher values of LDL and HDL significantly increase risk of breast cancer.