Cyclooxygenase-1 and -2 in human testicular tumours

Dihydroartemisinin, a potential PTGS1 inhibitor, potentiated cisplatin-induced cell death in non-small cell lung cancer through activating ROS-mediated multiple signaling pathways

Dihydroartemisinin (DHA) exerts an anti-tumor effect in multiple cancers, however, the molecular mechanism of DHA and whether DHA facilitates the anti-tumor efficacy of cisplatin in non-small cell lung cancer (NSCLC) are unclear. Here, we found that DHA potentiated the anti-tumor effects of cisplatin in NSCLC cells by stimulating reactive oxygen species (ROS)-mediated endoplasmic reticulum (ER) stress, C-Jun-amino-terminal kinase (JNK) and p38 MAPK signaling pathways both in vitro and in vivo. Of note, we demonstrated for the first time that DHA inhibits prostaglandin G/H synthase 1 (PTGS1) expression, resulting in enhanced ROS production. Importantly, silencing PTGS1 sensitized DHA-induced cell death by increasing ROS production and activating ER-stress, JNK and p38 MAPK signaling pathways. In summary, our findings provided new experimental basis and therapeutic prospect for the combined therapy with DHA and cisplatin in some NSCLC patients.

Arachidonic Acid Pathways and Male Fertility: A Systematic Review

Arachidonic acid (AA) is a polyunsaturated fatty acid that is involved in male fertility. Human seminal fluid contains different prostaglandins: PGE (PGE₁ and PGE₂), PGF_2α, and their specific 19-hydroxy derivatives, 18,19-dehydro derivatives of PGE₁ and PGE₂. The objective of this study is to synthesize the available literature of in vivo animal studies and human clinical trials on the association between the AA pathway and male fertility. PGE is significantly decreased in the semen of infertile men, suggesting the potential for exploitation of PGE agonists to improve male fertility. Indeed, ibuprofen can affect male fertility by promoting alterations in sperm function and standard semen parameters. The results showed that targeting the AA pathways could be an attractive strategy for the treatment of male fertility.

Biomarkers of disease recurrence in stage I testicular germ cell tumours

Stage I testicular cancer is a disease restricted to the testicle. After orchiectomy, patients are considered to be without disease; however, the tumour is prone to relapse in ~4-50% of patients. Current predictive markers of relapse, which are tumour size and invasion to rete testis (in seminoma) or lymphovascular invasion (in non-seminoma), have limited clinical utility and are unable to correctly predict relapse in a substantial proportion of patients. Adjuvant therapeutic strategies based on available biomarkers can lead to overtreatment of 50-85% of patients. Discovery and implementation of novel biomarkers into treatment decision making will help to reduce the burden of adjuvant treatments and improve patient selection for adjuvant therapy.

RANKL regulates testicular cancer growth and Denosumab treatment has suppressive effects on GCNIS and advanced seminoma

BACKGROUND

Testicular germ cell tumours (TGCTs) have a high sensitivity to chemotherapy and a high cure rate, although with serious adverse effects. In the search for tumour suppressive drugs, the RANKL inhibitor Denosumab, used to treat osteoporosis, came up as a candidate since RANKL signalling was recently identified in the testis.

METHODS

Expression of RANKL, RANK and OPG, and the effects of RANKL inhibition were investigated in human TGCTs, TGCT-derived cell-lines, and TGCT-xenograft models. Serum RANKL was measured in TGCT-patients.

RESULTS

RANKL, RANK, and OPG were expressed in germ cell neoplasia in situ (GCNIS), TGCTs, and TGCT-derived cell lines. RANKL-inhibition reduced proliferation of seminoma-derived TCam-2 cells, but had no effect on embryonal carcinoma-derived NTera2 cells. Pretreatment with Denosumab did not augment the effect of cisplatin in vitro. However, inhibition of RANKL in vivo reduced tumour growth exclusively in the TCam-2-xenograft model and Denosumab-treatment decreased proliferation in human GCNIS cultures. In TGCT-patients serum RANKL had no prognostic value.

CONCLUSIONS

This study shows that the RANKL signalling system is expressed in GCNIS and seminoma where RANKL inhibition suppresses tumour growth in vitro and in vivo. Future studies are needed to determine whether RANKL is important for the malignant transformation or transition from GCNIS to invasive tumours.

Eicosanoid Biosynthesis in Male Reproductive Development: Effects of Perinatal Exposure to NSAIDs and Analgesic Drugs

Increasing rates of infertility associated with declining sperm counts and quality, as well as increasing rates of testicular cancer are contemporary issues in the United States and abroad. These conditions are part of the Testicular Dysgenesis Syndrome, which includes a variety of male reproductive disorders hypothesized to share a common origin based on disrupted testicular development during fetal and neonatal stages of life. Male reproductive development is a highly regulated and complex process that relies on an intricate coordination between germ, Leydig, and Sertoli cells as well as other supporting cell types, to ensure proper spermatogenesis, testicular immune privilege, and endocrine function. The eicosanoid system has been reported to be involved in the regulation of fetal and neonatal germ cell development as well as overall testicular homeostasis. Moreover, non-steroidal anti-inflammatory drugs (NSAIDs) and analgesics with abilities to block eicosanoid synthesis by targeting either or both isoforms of cyclooxygenase enzymes, have been found to adversely affect male reproductive development. This review will explore the current body of knowledge on the involvement of the eicosanoid system in male reproductive development, as well as discuss adverse effects of NSAIDs and analgesic drugs administered perinatally, focusing on toxicities reported in the testis and on major testicular cell types. Rodent and epidemiological studies will be corroborated by findings in invertebrate models for a comprehensive report of the state of the field, and to add to our understanding of the potential long-term effects of NSAID and analgesic drug administration in infants.

In vitro impact of genistein and mono(2-ethylhexyl) phthalate (MEHP) on the eicosanoid pathway in spermatogonial stem cells

Perinatal exposures to endocrine disrupting chemicals (EDCs) alter the male reproductive system. Infants are exposed to genistein (GEN) through soy-based formula, and to Mono(2-ethylhexyl) Phthalate (MEHP), metabolite of the plasticizer DEHP. Spermatogonial stem cells (SSCs) are formed in infancy and their integrity is essential for spermatogenesis. Thus, understanding the impact of EDCs on SSCs is critical. Prostaglandins (PGs) are inflammatory mediators synthesized via the eicosanoid pathway starting with cyclooxygenases (Coxs), that regulate physiological and pathological processes. Our goal was to study the eicosanoid pathway in SSCs and examine whether it was disrupted by GEN and MEHP, potentially contributing to their adverse effects. The mouse C18-4 cell line used as SSC model expressed high levels of Cox1 and Cox2 genes and proteins, and eicosanoid pathway genes similarly to levels measured in primary rat spermatogonia. Treatments with GEN and MEHP at 10 and 100 μM decreased Cox1 gene and protein expression, whereas Cox2, phospholipase A2, prostaglandin synthases transcripts, PGE2, PGF2a and PGD2 were upregulated. Simultaneously, the transcript levels of spermatogonia progenitor markers Foxo1 and Mcam and differentiated spermatogonial markers cKit and Stra8 were increased. Foxo1 was also increased by EDCs in primary rat spermatogonia. This study shows that the eicosanoid pathway is altered during SSC differentiation and that exposure to GEN and MEHP disrupts this process, mainly driven by GEN effects on Cox2 pathway, while MEHP acts through an alternative mechanism. Thus, understanding the role of Cox enzymes in SSCs and how GEN and MEHP exposures alter their differentiation warrants further studies.

International Union of Basic and Clinical Pharmacology. CIX. Differences and Similarities between Human and Rodent Prostaglandin E2 Receptors (EP1-4) and Prostacyclin Receptor (IP): Specific Roles in Pathophysiologic Conditions

Prostaglandins are derived from arachidonic acid metabolism through cyclooxygenase activities. Among prostaglandins (PGs), prostacyclin (PGI2) and PGE2 are strongly involved in the regulation of homeostasis and main physiologic functions. In addition, the synthesis of these two prostaglandins is significantly increased during inflammation. PGI2 and PGE2 exert their biologic actions by binding to their respective receptors, namely prostacyclin receptor (IP) and prostaglandin E2 receptor (EP) 1-4, which belong to the family of G-protein-coupled receptors. IP and EP1-4 receptors are widely distributed in the body and thus play various physiologic and pathophysiologic roles. In this review, we discuss the recent advances in studies using pharmacological approaches, genetically modified animals, and genome-wide association studies regarding the roles of IP and EP1-4 receptors in the immune, cardiovascular, nervous, gastrointestinal, respiratory, genitourinary, and musculoskeletal systems. In particular, we highlight similarities and differences between human and rodents in terms of the specific roles of IP and EP1-4 receptors and their downstream signaling pathways, functions, and activities for each biologic system. We also highlight the potential novel therapeutic benefit of targeting IP and EP1-4 receptors in several diseases based on the scientific advances, animal models, and human studies. SIGNIFICANCE STATEMENT: In this review, we present an update of the pathophysiologic role of the prostacyclin receptor, prostaglandin E2 receptor (EP) 1, EP2, EP3, and EP4 receptors when activated by the two main prostaglandins, namely prostacyclin and prostaglandin E2, produced during inflammatory conditions in human and rodents. In addition, this comparison of the published results in each tissue and/or pathology should facilitate the choice of the most appropriate model for the future studies.

Selective COX-2 inhibitors as anticancer agents: a patent review (2014-2018)

INTRODUCTION

COX-2 is a key enzyme in the process of prostaglandins (PGs) synthesis. The products of this enzyme could play a major role as the mediators of the inflammatory response and some other medical states such as cancer. The design and synthesis of novel selective COX-2 inhibitors have always been attractive to researchers. This review discusses the structures of novel COX-2 inhibitors synthesized during the last five years and describes their efficacy as anticancer agents.

AREAS COVERED

It is well established that COX-2 is overexpressed in many different cancers and treatment with selective COX-2 inhibitors could relieve their symptoms and limit their adverse sequences.

EXPERT OPINION

The diversity of selective COX-2 inhibitors is mainly related to the types of scaffolds. Monocyclic, bicyclic, tricyclic, and acyclic scaffolds with different pharmacological effects and toxicological profiles could be found in the family of selective COX-2 inhibitors. The great interest of the researchers in this field is due to the importance of selective COX-2 inhibitors as a relatively safe and effective set of compounds which could present different properties such as antirheumatic, anti-inflammatory, antiplatelet, anti-Alzheimer's disease, anti-Parkinson's disease, and anticancer.

Protective effects of selenium and nano-selenium on bisphenol-induced reproductive toxicity in male rats

Bisphenol A (BPA) is a widespread compound associated with the manufacture of many consumer products. The BPA-induced reproductive toxicity was reported to be mainly attributed to oxidative stress. However, the role of antioxidants usage to decrease the injurious effects of BPA, on male reproductive functions, remains to unveil. The present research is established to evaluate the role of selenium (Se) and its nano form (NSe) as protective agents to alleviate BPA-induced testicular toxicity. Ninety mature albino male rats were assigned into six equal groups: negative control; orally BPA 150 mg/kg; Se 3 mg/kg; NSe 2 mg/kg; both BPA 150 mg/kg and Se 3 mg/kg; and BPA 150 mg/kg + NSe 2 mg/kg. The experiment lasted for 70 consecutive days, and then serum was collected for estimation of prostatic acid phosphatase. Testicular tissues were subjected to measurement of antioxidant status, lipid peroxidation, DNA damage, and expression of some apoptotic genes. Our results reported that BPA-induced marked testicular damage evidenced by significant elevations in serum prostatic acid phosphatase activity, malondialdehyde levels, a decrease in testicular catalase activity and reduced glutathione level. Moreover, marked DNA internucleosomal fragmentation pattern as well as upregulation of cyclooxygenase-2 and estrogen receptor-2 NSe genes were detected. Coadministration of Se and NSe attenuated the reproductive toxicity induced by BPA via improvement of the antioxidant activity, genetic changes, and restoration of testicular tissue nearly as control one. These results indicated that both Se and NSe forms could be used as reproductive protective agents against the detrimental effect induced by BPA. However, the NSe surpassed the selenium in modulating the DNA laddering, and the studied gene expression levels, and offered a potent reproductive protection.

Prostaglandin E2 (PGE2) is a testicular peritubular cell-derived factor involved in human testicular homeostasis

In man, blockage of prostaglandin (PG)-production e.g. by non-steroidal anti-inflammatory drug (NSAIDs) may have negative testicular side effects, implying beneficial actions of PGs in the testis. We examined human testicular samples and isolated human testicular peritubular cells (HTPCs) to explore sites of PG-synthesis and targets. HTPCs express cyclooxygenase 1 (COX1) and secrete PGE2. Receptors (EP1, 2, 4) were specifically identified in peritubular cells. In HTPCs PGE2 significantly increased mRNA levels of the contractility protein calponin, but did not induce contractions. PGE2, as well as EP1 and EP4 receptor agonists, significantly increased glia cell line derived neurotrophic factor (GDNF) mRNA and/or protein levels. Importantly, the NSAID ibuprofen reduced PGE2 and this action also lowered SMA and calponin mRNA levels and levels of secreted GDNF protein. The results reveal an unknown PGE2 system in the human testis, in involving peritubular cells, which may be prone to interference by NSAIDs.

Expression of PTGS2, PGFS and PTGFR during downregulation and restart of spermatogenesis following GnRH agonist treatment in the dog

Prostaglandins (PGs) and prostaglandin endoperoxide synthase (PTGS) are considered to be relevant for spermatogenesis and steroidogenesis. PTGS2, prostaglandin F synthase (PGFS) and PGF receptor (PTGFR) are investigated in the adult male dog using the model of the GnRH-agonist implant downregulated canine testis and its subsequent restart of spermatogenesis following abolition of treatment (3, 6, 9, 12 weeks after implant removal). On the mRNA level (ratio), PTGS2, PGFS and PTGFR expression did not differ between downregulation, different stages of recovery of spermatogenesis and untreated adult controls (CG). On the protein level, Sertoli and Leydig cells in all samples and some peritubular cells stained immunopositive for PTGS2. In the tubular compartment, the percentage of the PTGS2-immunopositive area (PIA) and the mean PTGS2-staining intensity (gray scale, GS) did not differ between groups but in the interstitial compartment, the PIA (p = 0.0494) and the GS (p < 0.0001) were significantly upregulated during early recrudescence (week 3/6). Comparing downregulation by two GnRH-agonist implants with juvenile controls (JG) and CG, the mRNA expression (ratio) did not differ. In the tubular compartment, the GS (p = 0.0321) was significantly higher at downregulation compared to CG and in the interstitial compartment, the PIA (p = 0.0073) and the GS (p = 0.0097) were significantly higher in JG compared to downregulation/CG. PTGS2, PGFS and PTGFR mRNA and PTGS2 protein are regularly expressed in the adult, juvenile and downregulated canine testis and downregulation and subsequent recrudescence affect PTGS2 protein expression mainly in Leydig cells. PTGS2 expression in the downregulated testis resembles the one in seasonal Syrian hamster but not juvenile canine testis.

Nonylphenol regulates cyclooxygenase-2 expression via Ros-activated NF-κB pathway in sertoli TM4 cells

The aim of this study was to investigate the signaling pathways involved in the cyclooxygenase (COX)-2 regulation induced by nonylphenol (NP) in mouse testis Sertoli TM4 cells. Our results showed that treatment of TM4 cells with NP increased COX-2 protein expression and interleukin-6 (IL)-6 and prostaglandin E2 (PGE2) secretion in a dose-dependent manner. Pretreatment with reactive oxygen species (ROS) scavenger, N-acetylcysteine (NAC), attenuated NP-induced ROS production, COX-2 expression, and IL-6 and PGE2 release in TM4 cells. Exposure to NP stimulated activation of NF-κB, whereas the NF-κB inhibitor, pyrrolidine dithiocarbamate, attenuated NP-enhanced COX-2 expression and IL-6 and PGE2 release in TM4 cells in a dose-dependent manner. Furthermore, NAC blocked NP-induced activation of NF-κB. In addition, inhibition of COX-2 mitigated NP-induced IL-6 release. In conclusion, NP induced ROS generation, activation of NF-κB pathway, COX-2 upregulation, and IL-6 and PGE2 secretion in TM4 cells. NP may regulate COX-2 expression via ROS-activated NF-κB pathway in Sertoli TM4 cells.

Cyclooxygenase and prostaglandins in somatic cell populations of the testis

Prostaglandins (PGs) are synthesized through the action of the rate-limiting enzyme cyclooxygenase (COX) and further specific enzymes. The development ofCox-deficient mice in the 1990s gave insights into the reproductive roles of PGs. FemaleCox-knockout mice were subfertile or infertile. Interestingly, fertility was not affected in male mice deficient inCox, suggesting that PGs may not be critical for the functioning of the testis. However, this conclusion has recently been challenged by observations of important roles for PGs in both physiological and pathological processes in the testis. The two key somatic cell types in the testis, Leydig and Sertoli cells, express the inducible isoenzyme COX2 and produce PGs. Testicular COX2 expression in these somatic cells is regulated by hormonal input (FSH, prolactin (PRL), and testosterone) as well as by IL1β. PGs modulate steroidogenesis in Leydig cells and glucose uptake in Sertoli cells. Hence, the COX2/PG system in Leydig and Sertoli cells acts as a local modulator of testicular activity, and consequently may regulate spermatogenic efficiency. In addition to its expression in Leydig and Sertoli cells, COX2 has been detected in the seminiferous tubule wall, and in testicular macrophages and mast cells of infertile patients. These observations highlight the possible relevance of PGs in testicular inflammation associated with idiopathic infertility. Collectively, these data indicate that the COX2/PG system plays crucial roles not only in testicular physiology (i.e., development, steroidogenesis, and spermatogenesis), but more importantly in the pathogenesis or maintenance of infertility status in the male gonad. Further studies of these actions could lead to new therapeutic approaches to idiopathic male infertility.

Free German abstract

A German translation of this abstract is freely available athttp://www.reproduction-online.org/content/149/4/R169/suppl/DC1.

Free Spanish abstract

A Spanish translation of this abstract is freely available athttp://www.reproduction-online.org/content/149/4/R169/suppl/DC2.

Multiple roles of the prostaglandin D2 signaling pathway in reproduction

Prostaglandins signaling molecules are involved in numerous physiological processes. They are produced by several enzyme-limited reactions upon fatty acids, which are catalyzed by two cyclooxygenases and prostaglandin synthases. In particular, the prostaglandins E2(PGE2), D2(PGD2), and F2(PGF2α) have been shown to be involved in female reproductive mechanisms. Furthermore, widespread expression of lipocalin- and hematopoietic-PGD2synthases in the male reproductive tract supports the purported roles of PGD2in the development of both embryonic and adult testes, sperm maturation, and spermatogenesis. In this review, we summarize the putative roles of PGD2signaling and the roles of both PGD2synthases in testicular formation and function. We review the data reporting the involvement of PGD2signaling in the differentiation of Sertoli and germ cells of the embryonic testis. Furthermore, we discuss the roles of lipocalin-PGD2synthase in steroidogenesis and spermatogenesis, in terms of lipid molecule transport and PGD2production. Finally, we discuss the hypothesis that PGD2signaling may be affected in certain reproductive diseases, such as infertility, cryptorchidism, and testicular cancer.

Evaluation of the reproductive toxicity of naproxen sodium and meloxicam in male rats

Nonsteroidal anti-inflammatory drugs that are cyclooxygenase (COX) enzyme inhibitors have generally been used in short-term pain management and also to treat inflammation chronically. It is known that COX enzyme and prostaglandins play important roles in the regulation of reproductive functions in females. However, there are relatively few studies for the male reproductive system, and the results of these studies are contradictory. In this study, sperm count and motility, COX-1, COX-2, prostaglandin E1 (PGE1), prostaglandin E2 (PGE2), and prostaglandin F2α (PGF2α) levels in testis tissue, plasma follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone levels, and histopathological examination of testis tissue were evaluated after naproxen sodium and meloxicam administration in male rats. Also, testis superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), and glutathione (GSH) levels were measured to investigate the oxidation status. According to our results, sperm count and motility were significantly decreased in treatment groups. Plasma hormone levels did not show any statistical differences between the groups. COX-1, PGE2, and PGF2α levels were significantly decreased, while the decreases in COX-2 and PGE1 levels did not show any significance statistically. Testis SOD, catalase, GPx, and GSH levels were decreased significantly. According to the results of histopathological examination, damage in seminiferous tubules, where spermatogenesis developed, was observed. In conclusion, naproxen sodium and meloxicam decreased the sperm count and motility and also induced the damage of seminiferous tubules as a direct effect without affecting plasma hormone levels in our study. The mechanism of the reproductive toxicity induced by these agents may be based on the inhibition of prostaglandin synthesis and the induction of oxidative stress can be emphasized as a secondary factor.

Establishment and characterization of seven human breast cancer cell lines including two triple-negative cell lines

Permanently growing cell lines can be invaluable because of their usefulness in a variety of experimental situations. We report the characteristics of seven cell lines designated, SNU-306, SNU-334, SNU-1528, SNU-1553, SNU-1581, SNU-1958 and SNU-2372, which were established from three primary carcinomas, two pleural effusion, one pericardial effusion and one ascitic fluid samples obtained from seven Korean breast carcinoma patients. The histopathology of the primary tumors and their in vitro growth characteristics are described. DNA fingerprinting analysis and genetic alterations in the p53 and EGFR genes were conducted. The expression levels of the ER-α, PR, C-erbB2, E-cadherin, COX-2, MDR and MXR genes were investigated and sensitivity to anticancer drugs was screened. Growth was as adherent cells (four cell lines), floating aggregates (one cell line) and both (two cell lines). All lines were free of mycoplasma or bacteria and were proven unique by DNA fingerprinting analysis using 18 microsatellite markers. Estrogen receptor (ER) mRNA was highly expressed in five cell lines and low or undetectable in SNU-1958 and SNU-2372. Progesterone receptor (PR) mRNA was expressed only in the SNU-306. SNU-1958 and SNU-2372 were hormone receptor-negative and C-erbB2-negative (triple-negative). SNU-1528 had an in-frame deletion of 42 base pairs of p53 gene and showed over 20-fold resistance for taxol compared to the other cell lines. There were no mutation in the EGFR gene; COX-2 was expressed in four cell lines and MXR was expressed in two cell lines. These well-characterized seven breast cancer cell lines, which include two triple-negative cell lines, will be useful for the study of breast cancer biology.

Exploring the cyclooxygenase 2 (COX2)/15d-Δ(12,14)PGJ(2) system in hamster Sertoli cells: regulation by FSH/testosterone and relevance to glucose uptake

We have previously described a stimulatory effect of testosterone on cyclooxygenase 2 (COX2) expression and prostaglandin (PG) synthesis, and the involvement of PGs in the modulation of testosterone production in Leydig cells of the seasonal breeder Syrian hamster. In this study, we investigated the existence of a COX2/PGs system in hamster Sertoli cells, its regulation by testosterone and FSH, and its effect on glucose uptake. COX2 expression was observed in Sertoli cells of both reproductively active and inactive adult hamsters. Testosterone and the plasma membrane-impermeable testosterone-BSA significantly induced COX2 expression, mitogen activated protein kinases 1/2 (MAPK1/2) phosphorylation and 15d-Δ(12,14)PGJ(2) production in Sertoli cells purified from photoperiodically regressed hamsters. These actions were abolished by the antiandrogen bicalutamide and by the inhibitor of MAPK kinase (MEK1/2) U0126, suggesting that testosterone exerts its stimulatory effect on COX2/PGs through a non-classical mechanism that involves the presence of androgen receptors and MAPK1/2 activation. FSH also stimulated COX2/PGs via MAPK1/2 phosphorylation. FSH and testosterone stimulate, whereas 15d-Δ(12,14)PGJ(2) via PPARγ inhibits, [2,6-(3)H]-2-deoxy-d-glucose ([(3)H]-2-DOG) uptake. Meloxicam, a selective COX2 inhibitor, further increases [(3)H]-2-DOG uptake in the presence of FSH or testosterone. Thus, in addition to their positive effect, FSH and testosterone may also exert an indirect negative regulation on glucose uptake which involves the COX2/15d-Δ(12,14)PGJ(2)/PPARγ system. Overall, these results demonstrate the presence of a COX2/PG system in hamster Sertoli cells which might act as a local modulator of FSH and testosterone actions.

Expression of cyclooxygenase-1 (COX-1) and COX-2 in human male gametes from normal patients, and those with varicocele and diabetes: a potential molecular marker for diagnosing male infertility disorders

Rising rates of varicocele and diabetes mellitus (DM) pose a significant problem to human fertility. Recent studies have pointed out the impact of cyclooxygenase (COX) in the regulation of testicular function and male fertility. Prominent COX-2 expression has been described recently in the testes of infertile patients, but little is known about the role and identity of COX isoforms in human sperm under certain disease states such as varicocele and DM. We therefore examined the expression profile and ultrastructural localization of COX-1 and COX-2 concomitantly in semen samples from healthy donors, and patients with varicocele and DM. Using Western blotting assay, 'varicocele' and 'diabetic' sperm showed enhanced COX isoforms expression with respect to the 'healthy' sperm. Immunogold labeling revealed human sperm anatomical regions containing COX-1 and COX-2, confirming their increased expression in pathological samples. Our data demonstrate that both COX isoforms are upregulated in the spermatozoa of varicocele and diabetic patients, suggesting the harmful effect of the diseases also at the sperm molecular level, going beyond the abnormal morphology described to date. In conclusion, COX enzymes may possess a biological relevance in the pathogenesis and/or maintenance of male factor infertility associated with varicocele and DM, and may be considered additional molecular markers for the diagnosis of male infertility disorders.

Prolactin (PRL) induction of cyclooxygenase 2 (COX2) expression and prostaglandin (PG) production in hamster Leydig cells

Serum prolactin (PRL) variations play a crucial role in the photoperiodic-induced testicular regression-recrudescence transition in hamsters. We have previously shown that cyclooxygenase 2 (COX2), a key enzyme in the biosynthesis of prostaglandins (PGs), is expressed mostly in Leydig cells of reproductively active hamsters with considerable circulating and pituitary levels of PRL. In this study, we describe a stimulatory effect of PRL on COX2/PGs in hamster Leydig cells, which is mediated by IL-1β and prevented by P38-MAPK and JAK2 inhibitors. Furthermore, by preparative isoelectric focusing (IEF), we isolated PRL charge analogues from pituitaries of active [isoelectric points (pI): 5.16, 4.61, and 4.34] and regressed (pI: 5.44) hamsters. More acidic PRL charge analogues strongly induced COX2 expression, while less acidic ones had no effect. Our studies suggest that PRL induces COX2/PGs in hamster Leydig cells through IL-1β and activation of P38-MAPK and JAK2. PRL microheterogeneity detected in active/inactive hamsters may be responsible for the photoperiodic variations of COX2 expression in Leydig cells.

Regulation of smooth muscle contraction by the epithelium: role of prostaglandins

As an analog to the endothelium situated next to the vascular smooth muscle, the epithelium is emerging as an important regulator of smooth muscle contraction in many vital organs/tissues by interacting with other cell types and releasing epithelium-derived factors, among which prostaglandins have been demonstrated to play a versatile role in governing smooth muscle contraction essential to the physiological and pathophysiological processes in a wide range of organ systems.

Investigation into association and expression of PLCz and COX-2 as candidate genes for boar sperm quality and fertility

Phospholipase C zeta (PLCz) and cyclooxygenase isoenzyme type 2 (COX-2) are important in spermatogenesis, but their effect has not yet confirmed in pigs. Therefore, this study was aimed to analyse their association with sperm quality and fertility and to identify the mRNA and protein expression in boars reproductive tissues. DNA samples from 231 Pietrain (PI) and 109 Pietrain × Hampshire (PIHA) pigs with records of sperm quality [sperm concentration (SCON), motility, semen volume, plasma droplet and abnormal spermatozoa rate] and fertility (non-return rate and number of piglet born alive) traits were available. A SNP in non-coding region of PLCz g.158 A > C was associated with SCON (p < 0.05) in PIHA population while the polymorphism of COX-2 g.68 G > A in 3' UTR was not associated with any traits. For mRNA and protein expression study, a total of six boars were divided into two groups with G-I and G-II, where G-I was characterized for relatively better sperm quality. Both genes expressed higher in reproductive tissues compared with non-reproductive tissues. Phospholipase C zeta mRNA expressed higher in testis (p < 0.01), all parts of epididymis and spermatozoa from G-I, while COX-2 expressed higher in testis (p < 0.05), head and body of epididymis (p < 0.01), and spermatozoa from G-II boar. Both proteins were localized in Leydig cells and spermatozoa. These results might shed light on roles of these genes in spermatogenesis as candidate for boar sperm quality and fertility, but still the lack of association across populations should be considered.

Immunopresence and enzymatic activity of nitric oxide synthases, cyclooxygenases and PGE2-9-ketoreductase and in vitro production of PGF2α, PGE2 and testosterone in the testis of adult and prepubertal alpaca (Lama pacos)

This study presents the first evidence for differences in COXs, PGE2-9-ketoreductase and NOSs immunopresence and enzyme activity, and prostaglandin and testosterone production between the testes of adult and prepubertal alpacas. The prepubertal testis immunohistochemical data revealed that COX1 was expressed in spermatogonia and endothelial cells whereas COX2 was present only in the stromal cells. In adult animals, COX2 immunosignals were evidenced in germ cells, as well as both COX1 and -2 in Leydig and Sertoli cells. In adult testes, the spermatogonia, spermatocytes and round spermatids had expression of e- and n-NOS only, whereas elongated spermatids exhibited immunopositivity for i- and e-NOS and Sertoli cells expressed only n-NOS. In prepubertal alpacas, i-NOS was localized in spermatogonia, e-NOS in Sertoli cells and all three NOS isoforms in Leydig cells. PGE2-9-ketoreductase immunopresence was observed in spermatogonia nuclei and cytoplasm of prepubertal testis whereas they were localized in spermatid acrosomal vesicle of adult. The enzymatic data indicated that COX1 activity was higher than COX2 in adult alpaca testis whereas the activity of COX2 was greater than that of COX1 in prepubertal animals. Total NOS and PGE2-9-ketoreductase activities were more extensive in adult alpacas. In vitro hormone production results showed that prepubertal testes released lower amounts of testosterone and PGF2α while PGE2 synthesis was six times more elevated than in in vitro incubated adult testes. Taken together, the data on COX2, i-NOS and PGE2 led us to hypothesize that development in prepubertal male reproductive tissues utilizes a mechanism similar to that of inflammation.

Cafeteria diet increases prostaglandin E2 levels in rat prostate, kidney and testis

Nutrient composition, particularly the omega-6/omega-3 polyunsaturated fatty acids ratio, may differently affect inflammatory mediators production in tissues, which could be causally related to increased cancer incidence in obesity. We evaluated prostaglandin E(2) levels in male Wistar rat prostate, kidney and testicle tissues after 15 days of either a high fat, cafeteria-style diet (5.50 Kcal/g, 30 percent calories from fat, omega-6/omega-3 ratio 2.33) or a standard laboratory chow diet (3.35 Kcal/g, 3 percent calories from fat, omega-6/omega-3 ratio 0.56). In the cafeteria diet compared to standard laboratory diet rats, we found both an increase in weight gain and increased prostaglandin E(2) (PGE(2)) levels in prostate, kidney and testicle tissues. The increased levels of PGE(2) induced by the cafeteria diet could drive an inflammatory process leading to increased incidence of prostate, kidney and testicular cancer in overweight patients.

Establishment and characterization of six human lung cancer cell lines: EGFR, p53 gene mutations and expressions of drug sensitivity genes

BACKGROUND

Six human lung cancer cell lines (SNU-371, SNU-963, SNU-1327, SNU-1330, SNU-2292 and SNU-2315) were newly established through primary cell cultures. These cell lines were derived from a pulmonary blastoma, a small cell lung cancer, three adenocarcinomas and a squamous cell carcinoma of the lung of six Korean lung cancer patients.

METHODS

The histopathology of the primary tumors and their in vitro growth characteristics were described. DNA fingerprinting analysis and genetic alterations in the p53, β-catenin, TGFβRII, K-ras and EGFR genes were conducted. mRNA expressions levels of E-cadherin, COX-2, MDR1, MXR, CGA, synatophysin and TTF1 genes were investigated and sensitivity to anticancer drugs was screened.

RESULTS

Five cell lines grew as adherent cells and one cell line grew as floating aggregates. All lines were free of mycoplasma or bacteria and were proven unique by DNA fingerprinting analysis. A significant polymorphism at codon 72 (Arg to Pro) of the p53 gene was found in one line (SNU-1327) and a mutation at codon 176 was found in SNU-2292. No mutations in the K-ras, β-catenin and TGF-βRII genes were observed. E-cadherin was not expressed in SNU-371 and COX-2 was overexpressed in SNU-1330, SNU-2292 and SNU-2315 cell lines. MDR1 was overexpressed in SNU-371 and SNU-2292 cell lines and MXR was overexpressed in SNU-1327 cell line. Interestingly, the SNU-371 cell line derived from a pulmonary blastoma and which overexpressed MDR1 displayed cross resistance for several anticancer drugs. Neuroendocrine markers, chromogranin A and synaptophysin, were overexpressed in the small cell lung cancer cell line, SNU-963 and thyroid transcription factor-1 was also over expressed in this cell line. Two mutations (p.Glu746_Ser752delinsVal and p.Glu746_Ala750del) in exon 19 of EGFR were found in SNU-1330 and SNU-2315 cell lines, respectively.

CONCLUSION

These well-characterized lung cancer cell lines may be useful tools for investigations of the biological characteristics of lung cancers, particularly for investigations related to mutations of EGFR.

15-Deoxy-delta 12-14-prostaglandin-J2 induces hypertrophy and loss of contractility in human testicular peritubular cells: implications for human male fertility

The wall of the seminiferous tubules contains contractile smooth-muscle-like peritubular cells, thought to be important for sperm transport. Impaired spermatogenesis in men typically involves remodeling of this wall, and we now found that smooth muscle cell (SMC) markers, namely myosin heavy chain (MYH11) and smooth muscle actin (SMA) are often lost or diminished in peritubular cells of testes of men with impaired spermatogenesis. This suggests reduced contractility of the peritubular wall, which may contribute to sub- or infertility. In these cases, testicular expression of cyclooxygenase-2 (COX-2) implies formation of prostaglandins (PGs). When screening different PGs for their ability to target human testicular peritubular cells (HTPCs), only a PG metabolite, 15-deoxy-Delta(12-14)-prostaglandin-J2 (15dPGJ2), was effective. In primary cultures of HTPCs, 15dPGJ2 increased cell size in a reversible manner. Importantly, 15dPGJ2 treatment resulted in a loss of typical differentiation markers for SMCs, namely MYH11, calponin, and SMA, whereas fibroblast markers were unchanged. Collagen gel contraction assays revealed that this loss correlates with a reduced ability to contract. Experiments with an antagonist (bisphenol A diglycidyl ether) and agonist (troglitazone) for a cognate 15dPGJ2 receptor (i.e. peroxisome proliferator-activated receptor-gamma) indicated that peroxisome proliferator-activated receptor-gamma is not directly involved. Rather, the mode of action of 15dPGJ2 involves reactive oxygen species. The antioxidant N-acetylcysteine not only blocked ROS formation but also prevented the increase in cell size and the loss of contractility in HTPCs challenged with 15dPGJ2. We conclude that 15dPGJ2, via reactive oxygen species, influences SMC phenotype and contractility of human peritubular cells and possibly is involved in the development of human male sub-/infertility.

Establishment and characterization of 13 human colorectal carcinoma cell lines: mutations of genes and expressions of drug-sensitivity genes and cancer stem cell markers

Thirteen human colorectal cancer (CRC) cell lines were established from 10 primary tumors and 3 metastatic tumors obtained from 13 Korean patients. Characteristics of the cell lines including morphology in vivo and in vitro; mutations of the K-ras, p53, APC and MMR genes and microsatellite instability (MSI) status in vitro were determined. Expression of drug-sensitivity genes including MDR1, MXR, MRP1 and COX2 was also analyzed. The cell lines were unique as judged by DNA fingerprinting using 16 short tandem repeats. Eleven of the cell lines grew as adherent populations and the remaining two as floating aggregates. None of the cell lines were contaminated with Mycoplasma or bacteria. All cell lines showed high viability with relatively long doubling times. Six cell lines contained mutations at K-ras. Seven cell lines displayed p53 gene missense, nonsense and frameshift mutations. MSI was found in three cell lines and two cell lines with an MSI-high phenotype-possessed hMLH1 mutations. Nine cell lines had an APC mutation. MRP1 was highly expressed in all cell lines, and high expression of MDR1, MXR and COX2 evident in eight, six and six cell lines, respectively. Embryonal stem cell markers (MELK, SOX4 and OCT4) were expressed in most of cell lines. The cancer stem cell biomarkers CD133, CD44 and Lgr5 were expressed in 12, 13 and 13 cell lines, respectively. The presently well-characterized CRC cell lines should be useful in investigations of the biological characteristics of CRC, particularly for investigations related to gene alterations associated with CRC and biology of cancer stem cells.

Bisphenol A-induced aromatase activation is mediated by cyclooxygenase-2 up-regulation in rat testicular Leydig cells

Bisphenol A (4,4'-dihydroxy-2,2-diphenylpropane; BPA) is an endocrine disruptor that affects the reproductive health of wildlife and possibly of humans. Evidence suggests that BPA interrupts ovarian steroidogenesis by altering steroidogenic enzymes. We evaluated the effect of BPA on aromatase expression in rat testicular Leydig cells. In addition, we investigated whether cyclooxygenase-2 (COX-2) was involved in BPA-induced aromatase expression. BPA induced a time- and concentration-dependent increase in aromatase protein expression in rat testicular Leydig R2C cells. It also increased aromatase gene expression and its enzyme and promoter activity, but reduced testosterone synthesis; increased COX-2 mRNA expression and promoter activity, the production of prostaglandin E(2) (PGE(2)), and the gene expression of PGE(2) (EP2 and EP4) receptors; induced the activation of cyclic adenosine monophosphate (cAMP) response element (CRE) and CREB binding; and increased the phosphorylation of protein kinase A (PKA), Akt, and mitogen-activated protein (MAP) kinase signaling pathways. BPA activation of aromatase was reversed by various inhibitors (COX-2, PKA, Akt, ERK, JNK, and p38). Taken together, these results suggest that BPA increases aromatase activity, which is correlated with COX-2 up-regulation mediated by the CRE, PKA, Akt, and MAP kinase signaling pathways in rat testicular Leydig cells.

Inhibition of cyclooxygenase-2 down-regulates aromatase activity and decreases proliferation of Leydig tumor cells

Our recent studies have revealed that estrogens stimulate an autocrine mechanism determining Leydig tumor cell proliferation. Estrogen overproduction is due to an elevated steroidogenic factor-1 (SF-1) expression and cAMP-response element-binding protein (CREB) phosphorylation, both inducing aromatase overexpression. Although we have shown that increased SF-1 expression depends mainly on higher local insulin-like growth factor I production, the mechanisms and factors determining increased CREB activation in Leydig tumor cells are not completely understood. In this study, we investigated the role of cyclooxygenase-2 (COX-2) in CREB dependent-aromatase expression in Leydig tumor cells. We found that COX-2 is expressed in rat and human Leydigiomas as well as in the rat Leydig tumor cell line R2C, but not in normal testis. Our data indicate that in R2C cells the COX-2-derived prostaglandin E2 (PGE2) binds the PGE2 receptor EP4 and activates protein kinase A (PKA) and ultimately CREB. Inhibitors for COX-2 (NS398), EP4 (AH23848), and PKA (H89) decreased aromatase expression and activity as a consequence of a decreased phosphorylated CREB recruitment to the PII promoter of the aromatase gene. The COX-2/PGE2/PKA pathway also seems to be involved in aromatase post-translational activation, an observation that requires further studies. The reduction in aromatase activity was responsible for a drop in estrogen production and subsequent reduction in cyclin E expression resulting in a decrease in tumor Leydig cell proliferation. Furthermore, COX-2 silencing caused a significant decrease in CREB phosphorylation, aromatase expression, and R2C cell proliferation. These novel findings clarify the mechanisms involved in the growth of Leydig cell tumors and should be taken into account in determining new therapeutic approaches.

Synergistic inhibition effect of tumor growth by using celecoxib in combination with oxaliplatin

BACKGROUND

To evaluate the effects of celecoxib, in combination with oxaliplatin, on tumour growth, cell apoptosis and angiogenesis in nude mice models.

MATERIALS AND METHODS

Xenograft mice model of colon cancer was established using the BALB/c nude mice. Medicine was administered respectively in different groups. Tumour volumes, the expression level of survivin, beta-catenin, VEGF mRNA level, the microvessel density and cell apoptosis were measured.

RESULTS

Celecoxib, oxaliplatin and combination use caused a tumour inhibition of 35%, 31% and 63% respectively. Compared with control group, a significant redation of angiogenesis and the levels of COX-2, survivin and beta-cantenin protein, and increase of cell apoptosis were detected in tumors in celecoxib group. Celecoxib in combination with oxaliplatin could further promote cell apoptosis and reduce beta-catenin protein expression.

CONCLUSION

Celecoxib could inhibit tumor growth and enhance the antitumor effects of oxaliplatin through their synergistic role in inhibiting different targets.

Involvement of lipids in dimethoate-induced inhibition of testosterone biosynthesis in rat interstitial cells

The mechanism involved in the inhibition of testosterone (Te) biosynthesis after a sub-chronic exposure to low doses of dimethoate (D) was studied in rat interstitial cells (IC). Expression of COX-2 in IC isolated from D-treated rats increased by 44% over C data, while transcription of StAR decreased by approx. 50% and the expression of this protein was diminished by approximately 40%. PGE(2) and PGF(2alpha) were increased by 61 and 78%, respectively. Te concentration decreased by 49% in IC homogenates. Concomitantly, plasma concentration of LH and FSH both increased. Araquidonate (ARA) and C(22) fatty acyl chains in phospholipids from IC mitochondrial fraction decreased by approx. 30% after D treatment. Protein carbonyls, lipoperoxides and nitrite content increased while alpha-tocopherol and the antioxidant capacity of the soluble cellular fraction decreased significantly. Stimulation with h-CG 10 nM overnight failed to overcome the inhibition caused by D on both Te biosynthesis and 3beta- and 17beta-hydroxysteroid dehydrogenases. Decreased Te biosynthesis may be attributed to (1) inhibition of StAR protein activity due to the stimulation of COX-2 and the overproduction of PGF(2alpha), (2) decreased stimulatory effect of ARA on StAR with a subsequent reduction in the availability of CHO for the androgenic pathway, and/or (3) indirect inhibition of steroidogenic enzymes by a lower transcriptional rate caused by elevated PGF(2alpha). Rofecoxib administration prevents the deleterious effect(s) exerted by D.

Testosterone induction of prostaglandin-endoperoxide synthase 2 expression and prostaglandin F(2alpha) production in hamster Leydig cells

We have previously observed expression of prostaglandin-endoperoxide synthase 2 (PTGS2), the key enzyme in the biosynthesis of prostaglandins (PGs), in reproductively active Syrian hamster Leydig cells, and reported an inhibitory role of PGF(2alpha) on hamster testicular steroidogenesis. In this study, we further investigated PTGS2 expression in hamster Leydig cells during sexual development and photoperiodic gonadal regression. Since PTGS2 is mostly expressed in pubertal and reproductively active adult hamsters with high circulating levels of LH and androgens, we studied the role of these hormones in the regulation/maintenance of testicular PTGS2/PGF(2alpha). In active hamster Leydig cells, LH/hCG and testosterone induced PTGS2 and PGF(2alpha) production, and their actions were abolished by the antiandrogen bicalutamide (Bi). These results indicate that LH does not exert a direct effect on PG synthesis. Testosterone also stimulated phosphorylation of the mitogen-activated protein kinase isoforms 3/1 (MAPK3/1) within minutes and hours, but the testosterone metabolite dihydrotestosterone had no effect on PTGS2 and MAPK3/1. Because Bi and U0126, an inhibitor of the MAP kinase kinases 1 and 2 (MAP2K1/2), abolished testosterone actions on MAPK3/1 and PTGS2, our studies suggest that testosterone directly induces PTGS2/PGF(2alpha) in hamster Leydig cells via androgen receptors and a non-classical mechanism that involves MAPK3/1 activation. Since PGF(2alpha) inhibits testosterone production, it might imply the existence of a regulatory loop that is setting a brake on steroidogenesis. Thus, the androgen environment might be crucial for the regulation of testicular PG production at least during sexual development and photoperiodic variations in hamsters.

Non-steroidal anti-inflammatory drugs in the treatment of genitourinary malignancies: focus on clinical data

The antitumour activity of NSAIDs in preclinical trials has lead to their evaluation in the management of various malignancies in humans. Evidence regarding their use in the treatment of genitourinary tumours is reviewed here, focusing primarily on clinical data. The majority of available evidence comes from meeting abstracts and only a few published manuscripts were detected. The efficacy of selective COX-2 inhibitors, a subcategory of anti-inflammatory drugs, is promising in prostate cancer, in either biochemical recurrence after initial treatment or advanced disease. This does not seem to be the case for renal tumours in which efficacy in the advanced disease setting is not satisfactory. Despite the well-documented rationale for the application of NSAIDs in bladder cancer management, clinical evidence is not available. More studies are needed to assess the efficacy of anti-inflammatory agents in bladder cancer treatment and further clarify their therapeutic benefit in patients with prostate cancer, in which initial results are encouraging.

Transcriptome analysis of differentiating spermatogonia stimulated with kit ligand

Kit ligand (KL) is a survival factor and a mitogenic stimulus for differentiating spermatogonia. However, it is not known whether KL also plays a role in the differentiative events that lead to meiotic entry of these cells. We performed a wide genome analysis of difference in gene expression induced by treatment with KL of spermatogonia from 7-day-old mice, using gene chips spanning the whole mouse genome. The analysis revealed that the pattern of RNA expression induced by KL is compatible with the qualitative changes of the cell cycle that occur during the subsequent cell divisions in type A and B spermatogonia, i.e. the progressive lengthening of the S phase and the shortening of the G2/M transition. Moreover, KL up-regulates in differentiating spermatogonia the expression of early meiotic genes (for instance: Lhx8, Nek1, Rnf141, Xrcc3, Tpo1, Tbca, Xrcc2, Mesp1, Phf7, Rtel1), whereas it down-regulates typical spermatogonial markers (for instance: Pole, Ptgs2, Zfpm2, Egr2, Egr3, Gsk3b, Hnrpa1, Fst, Ptch2). Since KL modifies the expression of several genes known to be up-regulated or down-regulated in spermatogonia during the transition from the mitotic to the meiotic cell cycle, these results are consistent with a role of the KL/kit interaction in the induction of their meiotic differentiation.

A Prostaglandin D2 system in the human testis

As shown recently, cyclooxygenase 2 (COX2), the inducible key enzyme for the prostaglandin (PG) biosynthetic pathway, is abundantly present in interstitial cells of testes of men suffering from different forms of impaired spermatogenesis and sub- or infertility, but it is absent in human testes with normal spermatogenesis. Although the spectrum of the downstream products of COX2 action in testis, namely PGs, and their effects are not known, our results show that Prostaglandin D2 (PGD2) likely plays a role. We describe (a) PGD2 synthetases, as well as receptors for PGD2 (DP) in testicular interstitial cells of men suffering from spermatogenic damage and infertility, and report that (b) PGD2 is produced by and can affect Leydig cells of an animal model, which expresses testicular COX2 and DP.

Expression of 5-Lipoxygenase in human colorectal cancer

AIM: To evaluate the 5-lipoxygenases (Loxs) expression level in human colorectal cancer specimens in order to determine its clinicopathologic significance in human tumorigenesis.

METHODS: The relative quantity of 5-Lox mRNA in paired 91 colorectal tumor and adjacent normal mucosa samples was determined by real time quantitative PCR. Additionally, the expression of 5-Lox and cyclooxygenase (Cox)-2 proteins was also examined using immunohistochemical staining methods.

RESULTS: There was a marked increase in 5-Lox mRNA levels in the tumor compared with paired normal mucosa samples (P < 0.0001). Sixty six (72.5%) tumors showed high 5-Lox mRNA levels. The positivity rate of 5-Lox and Cox-2 protein expression was 68.7% and 79.1% respectively. There was a significant association between tumoral 5-Lox mRNA level and tumor size (Rho = 0.392, P = 0.0002), depth or vessel invasion.

CONCLUSION: These results suggest that 5-Lox is up-regulated in colorectal cancer and that inhibition of its expression might be valuable in the prevention and treatment of colorectal cancer.

Non-steroidal anti-inflammatory drugs to potentiate chemotherapy effects: from lab to clinic

Most solid tumors express the cyclooxygenase-2 (COX-2) protein, a target of NSAIDs. COX-2 overexpression in tumorsis considered a predictor of more advanced stage disease and of worse prognosis in a number of studies investigating solid malignancies. Therefore, NSAIDs are evaluated as anti-cancer drugs. NSAIDs inhibit proliferation, invasiveness of tumors, and angiogenesis and overcome apoptosis resistance in a COX-2 dependent and independent manner. This review will focus on the rationale behind NSAIDs, including selective COX-2 inhibitors, in combination with conventional chemotherapeutic drugs or novel molecular targeted drugs. Studies investigating anti-cancer effects of NSAIDs on cell lines and xenograft models have shown modulation of the Akt, NF-kappaB, tyrosine kinase and the death receptor-mediated apoptosis pathways. COX-2 expression in tumors is not yet used as biomarker in the clinic. Despite the increased risk on cardiovascular toxicity induced by selective COX-2 inhibitors, several ongoing clinical trials are still investigating the therapeutic benefits of NSAIDs in oncology. The anti-tumor effects in these trials balanced with the side effects data will define the precise role of selective COX-2 inhibitors in the treatment of cancer patients.

Cyclooxygenase-2 and prostaglandin F2 alpha in Syrian hamster Leydig cells: Inhibitory role on luteinizing hormone/human chorionic gonadotropin-stimulated testosterone production

We have previously found that cyclooxygenase-2 (COX-2), a key enzyme in the biosynthesis of prostaglandins (PGs), is present in the testicular interstitial cells of infertile men, whereas it is absent in human testes with no evident morphological changes or abnormalities. To find an animal model for further investigating COX-2 and its role in testicular steroidogenesis, we screened testes from adult species ranging from mice to monkeys. By using immunohistochemical assays, we found COX-2 expression only in Leydig cells of the reproductively active (peripubertal, pubertal, and adult) seasonal breeder Syrian hamster. COX-2 expression in hamster Leydig cells was confirmed by RT-PCR. In contrast, COX-1 expression was not detected in hamster testes. Because COX-2 expression implies PG synthesis, we investigated the effect of various PGs on testosterone production and found that PGF2 alpha stood out because it significantly reduced human chorionic gonadotropin-stimulated testosterone release from isolated hamster Leydig cells in a dose-dependent manner. This mechanism involves a decreased expression of testicular steroidogenic acute regulatory protein and 17beta-hydroxysteroid dehydrogenase. Testicular concentration and content of PGF2 alpha in reproductively active hamsters as well as production of PGF2 alpha from isolated hamster Leydig cells were also determined. Moreover, PGF2 alpha receptors were localized in Leydig cells of hamsters and testicular biopsies from patients with Sertoli cell only and germ arrest syndromes. Thus, in this study, we described a COX-2-initiated pathway that via PGF2 alpha production, PGF2 alpha receptors, steroidogenic acute regulatory protein, and 17beta-hydroxysteroid dehydrogenase represents a physiological local inhibitory system of human chorionic gonadotropin-stimulated testosterone production in the Syrian hamster testes.

Distribution of conjugated linoleic acid in total and subcellular fractions from normal and cancerous parts of human testes

The objective of the present study was to examine differences in the fatty acid composition of subcellular fractions from normal and cancerous parts of human testes. The conjugated linoleic acid (CLA) content was significantly higher in total testicular carcinoma (TC), but significantly lower in the mitochondrial fraction of TC in comparison to normal testicular tissue. The subcellular distribution pattern of CLA was similar to that of monounsaturated fatty acids, but different to that of 18:2n-6 (linoleic acid), underlining the different physiological properties of CLA and 18 : 2n-6. Because polyunsaturated fatty acids (PUFAs) have been suggested to have an effect on cancer risk and previous research has found that CLA inhibits the metabolism of 18 : 2n-6 into 20 : 4n-6, the contents of n-6 and n-3 PUFAs were determined. Significant differences were observed for 18 : 2n-6, 18 : 3n-3, 20 : 5n-3, and 22 : 6n-3, with 18 : 2n-6, 18 : 3n-3, and 20 : 5n-3 contents being higher and 22 : 6n-3 content being lower in TC than in normal testicular tissue. These results indicate a changed availability of substrates for the cyclooxygenase (COX) or lipooxygenase (LOX) pathways generating eicosanoids. Although not statistically significant, the reduced content of 20 : 4n-6 shown in this study might be due to an increased metabolism of this fatty acid into eicosanoids.

The expression of cyclooxygenases and lipoxygenases in renal ischemia-reperfusion injury

Recent studies of ischemia-reperfusion (I/R) injury have focused on the function of neutrophils as well as the actions of inflammatory cytokines. However, few reports address cyclooxygenases (COXs) and lipoxygenases (LOXs). We researched the expression of COXs (COX-1 and COX-2) and LOXs (5-LOX and 12-LOX) in rat renal I/R injury. The right kidney of male Lewis rats was excised, and the left renal artery and vein clamped for a 90-minute ischemia time. Rats were humanely killed at 0, 1.5, 3, 5, and 12 hours after reperfusion. COX and LOX expressions were studied using immunohistostaining. COX-2 and LOX expressions were observed only on endothelial cells of normal kidney. From 1.5 to 5 hours after reperfusion, COX-2 and LOXs expressions gradually intensified on endothelial cells. COX-2 and LOXs expression were most intense on endothelial cells at 5 hours after reperfusion. Twelve hours after reperfusion, necrosis extended throughout the ischemic kidney and nearly all the tubular epithelial cells were destroyed. Thus, at 12 hours after reperfusion, COX-2 and LOXs expressions on endothelial cells became weaker. However, COX-1 expression was not different at every time after reperfusion. COX-2 and LOXs were expressed in a rat model showing renal I/R injury. Several hours after the maximum of COX-2 and LOXs expressions, the maximal renal I/R injury was observed. These results suggest a relationship between COX-2 and LOXs expressions and renal I/R injury.

Cyclooxygenase-2 Expression

PURPOSE

Recent studies have shown that cyclooxygenase (Cox)-2 may be involved in colorectal carcinogenesis. We aimed to determine whether Cox-2 expression in itself can predict outcome of colorectal cancer patient after surgery. In addition, the expression of Cox-1 was also evaluated.

EXPERIMENTAL DESIGN

Tissue samples of primary and secondary tumors from 288 patients undergoing surgical resections for colorectal adenocarcinoma were immunohistochemically examined for Cox-2 and Cox-1 expressions. The specimens were graded based on the intensity and extent of staining; then, the correlations between Cox-2 and Cox-1 expressions with clinicopathologic parameters and survival time were analyzed.

RESULTS

Expression of Cox-2 was positive in 70.8% of primary tumor, 92.0% of lymph node metastases, 100.0% of hepatic metastases, and was significantly associated with tumor size, depth of invasion, lymph node metastasis, vessels invasion, stage and recurrence. In contrast, Cox-1 was positive in 42.7% of primary tumor, 84.0% of lymph node metastases, 37.5% hepatic metastases, and was associated with only tumor size. Patients with Cox-2-positive tumors had a significant shorter survival time than those with negative tumors did (P = 0.0006 by log-rank test); and, in a multivariate analysis, Cox-2 was an independent prognostic factor (P = 0.0103; relative risk 4.114; 95% confidence interval, 1.397-12.120). Cox-1 status had no statistically effect on patient survival time.

CONCLUSIONS

Elevated Cox-2 expression, but not that of Cox-1, was significantly associated with reduced survival and recognized as an independent prognostic factor in our cohort of colorectal cancer patients.