Cyclooxygenase-2 and 5-lipoxygenase converging functions on cell proliferation and tumor angiogenesis: implications for cancer therapy MARIO ROMANO*,1 AND JOAN CLA`RIA‡ *Department of Biomedical Sciences, University “G. D’Annunzio,” Ce.S.I., 66013 Chieti, Italy; and ‡ DNA Unit, Institut d’Investigacions Biome`diques August Pi i Sunyer (IDIBAPS), Hospital Clı´nic, Universitat de Barcelona, Barcelona 08036, Spain
THE CYCLOOXYGENASES
604 amino acids with an apparent molecular mass of 70 kDa (2, 7). COX-1 and COX-2 expression and tissue distribution are differentially regulated. COX-1 is ubiquitous and constitutively expressed throughout the gastrointestinal system, kidneys, vascular smooth muscle, and platelets (9). Conversely, COX-2 is undetectable in most tissues, but its expression can rapidly be induced by a variety of stimuli— growth factors and cytokines related to the inflammatory response (9). However, this distinction is not entirely accurate, since COX-1 can be induced or up-regulated under certain conditions and COX-2 has consistently been shown to be constitutively expressed in brain, kidney, as well as in megakaryocytes and newly formed platelets (9, 10). Immunoelectron microscopy and Western blot of COX-1 and COX-2 in subcellular fractions have revealed that COX-1 and COX-2 are located equally on the lumenal surfaces of the endoplasmic reticulum and nuclear envelope membranes (11).
Expression and localization
Catalytic activity
Cyclooxygenase (COX) and lipoxygenase (LO) metabolic pathways are emerging as key regulators of cell proliferation and neo-angiogenesis. COX and LO inhibitors are being investigated as potential anticancer drugs and results from clinical trials seem to be encouraging. In this article we will review evidence of COX-2 and 5-LO involvement in cancer pathobiology, propose a model of integrated control of cell proliferation by these enzymes, and discuss the pharmacologic implications of this model.—Romano, M., Cla`ria, J. Cyclooxygenase-2 and 5-lipoxygenase converging functions on cell proliferation and tumor angiogenesis: implications for cancer therapy. FASEB J. 17, 1986 –1995 (2003)
ABSTRACT
Key Words: arachidonic acid 䡠 cancer 䡠 cyclooxygenase and lipoxygenase inhibitors 䡠 eicosanoids
It was established in the early 1990s that there are at least two COX isoforms present in human cells: COX-1 and COX-2 (1, 2). A splice variant of COX-1, designated COX-3, that is especially sensitive to acetaminophen and related compounds has recently been identified (3). COX-1 and COX-2 are the products of two distinct genes, which in humans are localized on chromosomes 9 and 1, respectively (4, 5). The COX-1 gene is ⬃22 kb in length with 11 exons and is transcribed as a 2.8 kb mRNA (4, 6). The COX-2 gene is ⬃8 kb long with 10 exons and is transcribed as 4.6, 4.0, and 2.8 kb mRNAs variants (2, 7). Sequence analysis of the COX-2 5⬘-flanking region has revealed several potential transcription regulatory elements including a TATA box, a NF-IL-6 motif, two AP-2 sites, three Sp1 sites, two NF-B sites, a CRE motif, and an E-box (8). The amino acid sequences of COX-1 and COX-2 from a single species are ⬃60% identical. COX-1 is a glycoprotein that in its native, processed form has 576 amino acids with an apparent molecular mass of 70 kDa (4, 6). The cDNA for COX-2 encodes a polypeptide that before cleavage of the signal sequence contains 1986
COX transforms arachidonic acid into PGH2, the immediate precursor of various prostanoids, including prostaglandins (PGs) and thromboxane (TX). The COX pathway is of particular clinical relevance because it is the main target for drugs [such as nonsteroidal anti-inflammatory drugs (NSAIDs), COX-2 inhibitors (the so-called Coxibs) (12), and aspirin] used to relieve inflammation, pain, and fever and to prevent atherothrombosis. The basic catalytic activities of COX isozymes are similar enough to treat them as if they were biochemically identical. Accordingly, the biochemistry of these isozymes is discussed as one. COX is a bifunctional enzyme that catalyzes the first two committed steps in the pathway leading to the formation of PGs and TX, namely, cyclooxygenation 1
Correspondence: Laboratorio di Medicina Molecolare, Dipartimento di Scienze Biomediche, Universita` “G. D’Annunzio,” Ce.S.I., Via dei Vestini, 31, 66013 Chieti, Italy. E-mail:
[email protected] doi: 10.1096/fj.03-0053rev 0892-6638/03/0017-1986 © FASEB
and peroxidation. In fact, COX cyclizes and adds two molecules of O2 to arachidonic acid to form the cyclic hydroperoxide PGG2. It also reduces PGG2 to PGH2. PGH2 is a highly unstable endoperoxide that functions as an intermediate substrate for the biosynthesis, by specific synthases and isomerases, of PGs of the E2, F2 and D2 series and also PGI2 (prostacyclin) and TXA2. These reactions are cell and tissue specific. Although COX-1 and COX-2 oxygenate arachidonate with almost identical kinetics, in general COX-2 is much more efficient with alternative substrates. For instance, COX-2 uses both fatty acids and endocannabinoids, including 2-archidonylglycerol (2-AG) and anandamide (AEA), as substrates. COX-2 action on 2-AG and AEA generates endocannabinoid-derived prostanoids, among them PG glycerol esters and ethanolamides (13). Recent studies indicate that aspirin-acetylated COX-2 converts arachidonic acid to 15R-hydroxyeicosatetraenoic acid (HETE), which is further transformed into 15-epi-lipoxins (14). Moreover, when exposed to aspirin, COX-2-expressing cells enzymatically transform omega-3 docosaexaenoic acid (DHA) to previously unrecognized compounds, i.e., a novel 17R series of hydroxy-DHAs (15). Both 15-epi-lipoxins and hydroxyDHAs bear potent anti-inflammatory properties and play a key role in the resolution of inflammation. A schematic representation of these pathways is shown in Fig. 1. Prostanoids: receptors and functions Prostanoids activate specific receptors, which are also cell and tissue specific. There are at least nine known
PG receptors as well as several splice variants of them that belong to a subfamily of the G-protein-coupled receptor (GPCR) superfamily of seven transmembrane spanning proteins (16). Four of the receptor subtypes bind PGE2 (EP1-EP4), two bind PGD2 (DP1 and DP2) and the rest are single receptors for PGF2␣, PGI2 , and TXA2 (FP, IP, and TP, respectively) (16). IP, DP1, EP2, and EP4 receptors are coupled with the activation of Gs proteins and linked to increases in intracellular cAMP, whereas EP1 , FP, and TP signal through Gq-mediated increases in intracellular calcium concentration. Exceptionally, EP3 receptor is coupled to Gi and decreases cAMP formation. PGs generated from COX-2 located in the nuclear membrane, in addition to signaling through G-protein-linked receptors, may control nuclear pathways through interactions with peroxisome proliferator-activating receptors (PPARs) (17). This emphasizes the importance of COX-2 as a regulator of nuclear events in cell growth and survival. Activation of prostanoid receptors triggers a broad array of biological effects from the regulation of vascular tone, permeability, and platelet function to the induction of hyperalgesia and fever. See ref 18 for a detailed description of prostanoid bioactions.
COX-2 AND CANCER Although knockout studies provide evidence of COX1’s contribution to cancer development (19), COX-2 appears to be the isoform mainly involved in the pathogenesis of malignancy, particularly of colon cancer. The following are the most relevant findings ob-
Figure 1. Enzymatic pathways of PG formation from arachidonic acid. COX-1 and 2 oxygenate arachidonic acid to form PGG2 , which is further reduced to PGH2. PGH2 is a highly unstable endoperoxide that is rapidly converted by specific synthases and isomerases to PGs of the E2 , F2 , and D2 series and to PGI2 and TXA2 . PGI2 and TXA2 have a very short half-life (30 s and 3 min, respectively) and are rapidly hydrolyzed to the inactive compounds 6-keto-PGF1␣ and TXB2 , respectively. COX-2 also uses endocannabinoids, including 2-arachidonyl ethanolamide (anandamide), as substrates and generates endocannabinoidderived prostanoids, among them PG and TX glycerol esters and ethanolamides. When exposed to ASA, COX-2 converts arachidonic acid to 15RHETE and 15-epi-lipoxins and transforms fatty acids such as omega-3 docosaexaenoic acid (DHA) to a novel 17R series of hydroxy-DHAs termed resolvins. Both 15-epi-lipoxins and resolvins have potent bioactive properties in inflammation resolution. COX-2 AND 5-LO IN CANCER
1987
tained from several independent lines of research supporting the involvement of PGs and COX-2 in carcinogenesis. Increased levels of PGs in tumors The concentration of PGs, in particular PGE2 , is increased in human colorectal cancer tissue when compared with normal colonic mucosa (20). Similar findings were reported in experimental carcinogenesis and in macroscopically normal colon of rodents exposed to colonic carcinogens (21). Increased COX-2 expression in tumors Consistent with elevated PGE2 levels, increased expression of COX-2, but not of COX-1, was detected in colorectal carcinomas (22, 23). Published reports indicate that ⬃85% of adenocarcinomas exhibit a 2- to 50-fold increase in COX-2 expression at both the mRNA and protein level compared with matched macroscopically normal colonic mucosal, being the rectum the site of maximal expression (22, 23). However, the cellular origin of COX-2 overexpression in tumors is debated. Cancer cells, nontransformed epithelial cells, stromal fibroblasts, vascular endothelial cells, and inflammatory infiltrates are constituents of neoplastic colon tissue, and all of these cells are reported to display elevated COX-2 levels compared with the normal colon tissues (24). Other studies have shown that increased COX-2 expression in colon cancer originates mainly from the interstitial cells (i.e., macrophages), whereas little COX-2 expression was found in epithelial cancer cells (25). Several mechanisms for enhanced COX-2 gene expression in cancer have been suggested, including mutations of APC and ras, activation of EGF receptor and IGF-I receptor pathways and heregulin/HER-2 receptor pathway, direct induction by the Epstein-Barr virus oncoprotein, and latent membrane protein 1 (26, 27). COX-2 overexpression promotes tumorigenesis; COX-2 inhibition is anti-neoplastic The functional consequences of COX-2 overexpression have been analyzed mostly in the rat intestinal cell line (RIE cells), in the gastrocolonic cell lines HT-29 and HCA-7, and in the human colon cell line Caco-2 transfected with COX-2. In general, these experiments reveal that cells overexpressing COX-2 undergo phenotypic changes, including exhibition of increased adhesion to extracellular matrix proteins and resistance to apoptosis, which could enhance their tumorigenic potential (28). The proliferative activity of COX-2 is believed to be primarily mediated by PGs. In fact, the human gastrocolonic cancer cell line HT-29 shows increased proliferation in the presence of PGs in the culture medium (29). Moreover, in vivo, colonocyte proliferation is significantly stimulated by the injection 1988
Vol. 17
November 2003
of the stable derivative of PGE2 , dimethyl PGE2 , into normal mice (29). Consistently, transgenic COX-2 overexpression sensitizes mouse skin for tumor induction by carcinogens (30), whereas in APC⌬716 knockout mice, a model in which a targeted truncation deletion in the tumor suppressor gene APC causes intestinal polyposis, the number and size of the polyps were reduced dramatically (6- to 8-fold) when the COX-2 gene was knocked out (31). Further evidence of the role played by COX-2 in cancer growth was provided by the use of NSAIDs and Coxibs. Sheng et al. tested the effects of a highly selective COX-2 inhibitor (SC-58125) on two transformed human colon cancer cell lines, only one of which had high levels of COX-2 protein expression and activity (32). These authors observed that SC-58125 decreased cell growth only in the COX-2-expressing cell line (32). In contrast, Elder et al. reported a significant anti-proliferative effect of NS-38, a selective COX-2 inhibitor, in colon cancer cells that do not express COX-2 (33). These controversial findings together with the observation that NSAIDs such as sulindac sulfone, a sulindac metabolite devoid of COX inhibitory activity, are able to reduce colon cancer cell growth (34) suggest that COX-independent pathways could also be involved in the anti-proliferative effects of NSAIDs. A combination of epidemiological and experimental studies has demonstrated a clear association in vivo between regular long-term consumption of NSAIDs— aspirin in particular—and a reduced incidence in colon cancer (reviewed in ref 35). Aspirin and sulindac have been also shown to reduce the number and size of adenomatous colonic polyps in patients with familial adenomatous polyposis (FAP) (36). Epidemiological data in humans are well documented, because separate studies differing in location, design, and population have consistently shown that regular use of NSAIDs reduces the risk of colon cancer. Parallel studies in animal models of colon carcinogenesis have also proved that aspirin as well as other conventional NSAIDs such as piroxicam, indomethacin, sulindac, ibuprofen, and ketoprofen inhibits chemically induced colon cancer in rats and mice (reviewed in ref 35). In these studies, the mechanism by which NSAIDs reduce the risk of cancer is likely to be related to the inhibition of COX-2. A randomized clinical trial has shown that celecoxib significantly inhibits the growth of adenomatous polyps and causes regression of existing polyps in patients with hereditary FAP (37). Studies in rodents demonstrated that selective pharmacological inhibition of COX-2 activity prevents chemically induced carcinogenesis and intestinal polyp formation in an experimental model of FAP (38, 39). In Min mice and rats exposed to chemical carcinogens, selective COX-2 inhibitors induced apoptosis and suppressed growth of a variety of epithelial cancers (reviewed in ref 40). COX-2 may also be implicated in head and neck, lung, and pancreatic tumors, and the beneficial effects of Coxibs may be extended to these cancers (40 – 42). Along these lines, COX-2 inhibition appears to potentiate antitu-
The FASEB Journal
ROMANO AND CLA`RIA
mor activity of chemotherapeutic agents (43). This could be related to the recently discovered capability of COX-2 to block p53- or genotoxic stress-induced apoptosis (44). COX-2 induces neo-angiogenesis Recent results indicate that neo-angiogenesis, which is essential for tumor development, requires COX-2 (45). In fact, COX-2 overexpressing colon cancer cells produce large amounts of proangiogenic factors, including vascular endothelial growth factor (VEGF) (46), a key regulator of endothelial cell migration and in vitro angiogenesis. Also, tumors implanted in COX-2 (⫺/⫺) mice display a reduction in vascular density and growth (47). This may be in relation with the inability of COX-2 (⫺/⫺) stromal fibroblasts to produce VEGF (47). A relationship between COX-2 and VEGF expression can be also observed in prostate cancer cells and human breast cancer (48, 49). Furthermore, PGs induce expression of VEGF and of the VEGF transcription factor hypoxia-inducible factor-1 (50, 51). Nevertheless, a possible role for COX-1 in the regulation of angiogenesis cannot be excluded, since treatment of endothelial cells with either aspirin or COX-1 antisense oligonucleotides inhibits endothelial tube formation (46). Using the dual COX-1/-2 inhibitor diclofenac, Seed et al. showed that colorectal cancer growth is inhibited via the suppression of angiogenesis (52). On the other hand, more recent studies demonstrated that selective COX-2, but not COX-1, inhibitors suppress the growth of corneal capillary blood vessels in rats exposed to basic fibroblast growth factor and inhibit the growth of several human tumors implanted in mice (47, 53).
THE 5-LIPOXYGENASE Expression 5-LO, whose activity was first described in 1976 by Borgeat et al. (54), is a 78 kDa protein that catalyzes the biosynthesis of potent bioactive eicosanoids. The 5-LO gene is ⬎ 82 kb in length and encompasses 14 exons separated by 13 introns (55). The 5⬘-flanking region of this gene displays a unique (G⫹C)-rich sequence encompassing five tandem SP1 consensus regions, but not TATA or CCAAT sequences. The –179 to –56 DNA region appears to be essential for transcription initiation (56). The 5-LO promoter contains consensus regions for a number of transcription regulators belonging to the Egr, Sp, NF-B, GATA, myb, and AP families (56). Mutations characterized by alterations in the number of Sp1 and Egr-1 binding motifs associated with reduced reporter assay activity have been detected, although their pathophysiological role remains to be established (57). In humans, 5-LO is physiologically expressed in cells of the myeloid lineage, but also in B lymphocytes and pulmonary artery endothelial cells. However, the mechCOX-2 AND 5-LO IN CANCER
anisms that selectively regulate the degree of 5-LO gene expression remain elusive. It is known that transforming growth factor  and 1,25-dihydroxyvitamin D3 increase 5-LO mRNA accumulation and 5-LO activity (58), but a direct effect on 5-LO transcription by these agents has not been demonstrated. On the other hand, the 5-LO promoter is repressed by methylation of CpG sites within the (G⫹C)-rich sequence (59). It has been proposed that DNA demethylation may represent a key prerequisite for full 5-LO expression (59). Given the variety of putative transcription regulators of the 5-LO promoter, it is reasonable to assume that control of 5-LO expression may be quite complex and multifactorial. Catalytic activity and intracellular localization As other members of the LO family, 5-LO is a dioxygenase. It stereospecifically removes the pro-S hydrogen at carbon-7 of one of the 1,4-cis,cis-pentadiene structures present in its natural substrate, arachidonic acid. This reaction is accompanied by the insertion of molecular O2 at carbon-5, giving rise to 5(S)-hydroperoxy6E,8Z,11Z,14Z-eicosatetraenoic acid (HPETE). 5(S)HPETE can be reduced to 5(S)-hydroxy-6E,8Z,11Z,14Zeicosatetraenoic acid (HETE), which can be in turn dehydrogenated to 5-oxo-HETE. 5(S)-HPETE can also be subjected to the stereospecific removal of the pro-R hydrogen at carbon-10 to generate the highly unstable allylic epoxide 5(S),6(S)-oxido-7E,9E,11Z,15Z-eicosatetraenoic acid or leukotriene (LT)A4. This can be further metabolized by multiple routes, the best-characterized of which follow. 1) Conversion to LTB4 by LTA4 hydrolase (60). 2) Transformation to LTC4 by LTC4 synthase (61). LTC4 is further metabolized to LTD4 and LTE4. Together, LTC4 , D4 , and E4 correspond to the slowreacting substance of anaphylaxis (SRS-A) and are now termed cysteinyl leukotrienes (Cys-LTs). 3) Conversion to lipoxin (LX) A4 and B4 by 12- or 15-LO (62). A schematic representation of these pathways is shown in Fig. 2. For full activity 5-LO requires cofactors such as calcium, ATP, and a 18 kDa protein termed 5-LOactivating protein (FLAP), which facilitates the docking of arachidonic acid to 5-LO (63); post-translational modifications, i.e., phosphorylation by p38 kinase-dependent MAPKAP kinases (64); translocation to the nuclear envelope (65). This latter represents a unique feature of 5-LO not shared by other arachidonic acid catalyzing enzymes. In fact, 5-LO may be localized either in the cytoplasm or in the nuclear euchromatin, depending on the cell type, but it is always translocated to the nuclear membrane upon cell activation (65). It is at this site that 5-LO encounters phospholipase A2 and FLAP and where biosynthesis of 5-LO products is initiated (66). Nuclear import of 5-LO is crucial for 5(S)-HETE and LT biosynthesis, as 5-LO mutants lacking sequences involved in nuclear targeting are catalytically inactive (67). Recently, a basic region on human 5-LO encompassing residues 518-530 has been recog1989
Figure 2. The 5-LO pathway. 5-LO catalyzes the oxygenation of arachidonic acid to 5(S)-HpETE. 5(S)-HpETE can be reduced to 5(S)-HETE or subjected to the stereospecific removal of the pro-R hydrogen at carbon-10 to generate the highly unstable allylic epoxide LTA4. LTA4 is either hydrolyzed to LTB4 by a specific LTA4 hydrolase or converted into LTC4 by addition of the peptide glutathione by a specific LTC4 synthase. LTC4 can undergo further metabolism through a series of peptidic cleavage reactions to yield LTD4 and LTE4. LTA4 can also be converted to LXA4 and LXB4 by either 12- or 15-LO.
nized to meet the criteria of a nuclear import sequence (NIS) (68). 5-LO products: receptors and functions The most relevant pathophysiological role recognized to 5-LO products is regulation of the immune inflammatory response. LTB4 is in fact a potent activator of neutrophil chemotaxis and trans-endothelial migration, whereas the Cys-LTs, are key mediators of allergic inflammation. 5(S)-HETE and 5-oxo-HETE also activate neutrophils and/or monocytes. Specific receptors for LTB4 and Cys-LT have recently been cloned (69 – 72). More recently, a Gi/o-coupled eicosanoid receptor, recognized by 5-oxo-HETE has been identified (73). These findings represent a significant advance for a better understanding of the relevance of individual 5-LO products in health and disease. We already know that 5-LO knockout mice live normally and do not show appreciable dysfunctions; they are resistant to selected inflammatory damage, but more sensitive to bacteremia (74, 75). Genetic manipulation of receptors for 5-LO products may provide new insight into the biological significance of individual 5-LO pathways. 5-LO AND CANCER In recent years a participation of 5-LO in the regulation of cell proliferation and apoptosis has emerged. As in the case of COX-2, a number of observations (see below) document the involvement of 5-LO in cancer pathobiology. 5-LO is overexpressed in cancer cells and human tumors In addition to normal cells, 5-LO is expressed by a broad variety of cancer cells including colon, lung, 1990
Vol. 17
November 2003
breast, prostate, pancreas, bone, brain, and mesothelium (76 – 82). Human cancer tissues also display an enhanced expression of 5-LO (83). At least for human mesothelioma and pancreatic cancer, very low or undetectable 5-LO expression is observed in normal cells or tissues, whereas high 5-LO expression and activity are detected in the corresponding transformed cells or tissues (81, 82). Thus, 5-LO expression appears to be occasionally up-regulated during neoplastic transformation, although the sequelae of events connecting cancer development and 5-LO gene expression are unknown. Whether mutations of the 5-LO promoter region occur in cancer and whether oncogenes induce transcription of 5-LO remain to be investigated. Notably, expression of receptors for 5-LO products may also be relevant in cancer development. Indeed, CysLT1 is highly expressed in colorectal adenocarcinomas and its degree of expression correlates negatively with patient survival (84). 5-LO promotes cancer cell growth and neo-angiogenesis The biological functions of 5-LO in cancer cells have been examined using pharmacological inhibitors and/or antisense technology. Since the mid-1980s, when the anti-proliferative effects of 5-LO inhibitors on cancer cell lines began to be reported (85), a considerable number of studies have confirmed that 5-LO activity promotes cancer cell proliferation and survival. How this is achieved is not fully understood, although regulation of growth factor expression may be involved. We reported that 5-LO products, namely, 5(S)-HETE and LTA4 but not LTB4 , potently up-regulate VEGF transcription in a human malignant mesothelioma model (82). VEGF is a potent autocrine growth factor for mesothelioma cells and its selective suppression,
The FASEB Journal
ROMANO AND CLA`RIA
achieved with 5-LO antisense oligonucleotides and/or 5-LO inhibitors, results in apoptotic cell death (82). Since VEGF is also a potent proangiogenic factor and neo-angiogenesis and is crucial for tumor growth and invasion, it might be concluded that 5-LO promotes in vivo tumor development by a dual mechanism, a direct proliferative stimulus on cancer cells and a potentiation of the proangiogenic response by the host stromal cells. Indeed, 5-LO products up-regulate VEGF transcription in human umbilical vein endothelial cells (M. Romano et al., unpublished observation). On the other hand, 5-LO activity appears to interfere with the mechanisms of tumor suppression (A. Catalano et al., unpublished observation), suggesting that this enzyme may condition tumor response to genotoxic therapeutic agents.
COX-2 AND 5-LO CONVERGING PATHWAYS IN CANCER Analogies It is evident that COX-2 and 5-LO display similarities in expression and function in human cancer (see scheme in Fig. 3). First, COX-2 and 5-LO are coexpressed and up-regulated in a quite large number of cancer cells and human tumors, including lung, colon, prostate, breast, and mesothelioma (76, 82). Second, both 5-LO and COX-2 are proangiogenic with a convergent targeting on VEGF expression and release (46 –51, 82). Third, COX-2, as well as 5-LO inhibitors, arrest cell cycle progression and induce apoptotic cell death in a number of cancer cells (77, 78, 82, 85, 86). Fourth, both active COX-2 and 5-LO are localized in the nucleus (11, 65); COX-2 and 5-LO products may function as endogenous ligands for nuclear receptors as the PPARs, although this issue raises some controversy (87). Fifth, both COX-2 and 5-LO are up-regulated by
genotoxic stress and inhibit p53-induced cell death (ref 44 and A. Catalano et al., unpublished observation). Functional interactions and therapeutic implications COX-2 and 5-LO may have redundant functions in cancer pathobiology. Can we hypothesize that when coexpressed these arachidonic acid-metabolizing enzymes represent an integrated system that regulate the proliferative, proangiogenic potential of cancer cells? Should we include in this system other LOs (i.e., the 12 or 15 isoforms) that are often expressed in cancer cells? (76). Finally, how does this system work? Information on arachidonic acid metabolism in cancer is based largely on pharmacological studies. As outlined earlier in this review, COX-2 selective and nonselective inhibitors have been and are being used both in vitro and in vivo to block cancer progression. Animal studies and clinical trials with these drugs are encouraging, particularly in FAP and colorectal polyposis (35), although are still pending as to their side effects and precise mechanism(s) of action. NSAIDs may induce cancer cell apoptosis independent of COX-2 inhibition. For example, in esophageal cancer cells NSAIDs-induced apoptosis seems to depend on 15-LO up-regulation (88). On the other hand, a mechanism linking COX-2 inhibition to apoptosis could be an increase in concentration of free, unmetabolized arachidonic acid (89). According to this hypothesis, the blockade of arachidonic metabolism may increase the intracellular levels of unesterified arachidonate, which itself induces a concentration-dependent apoptotic response. If this is the case, when multiple metabolic pathways of arachidonic acid are present within the same cell, as in cancer cells coexpressing COX-2 and 5-LO (76), both enzymes should be blocked to achieve a substantial elevation in free arachidonic acid levels. Nevertheless, in these cells the simultaneous inhibition of COX-2 and 5-LO may
Figure 3. Both COX-2 and 5-LO stimulate cancer cell proliferation (upper panel), inhibit apoptosis (middle panel), and induce neo-angiogenesis (lower panel).
COX-2 AND 5-LO IN CANCER
1991
prevent the shunting of arachidonate toward 5-LO when COX-2 is blocked by NSAIDs, thus suppressing the production of 5-LO-derived mitogenic proangiogenic eicosanoids such as 5-oxo-HETE, 5(S)-HETE, and LTA4. However, this may represent an oversimplistic representation of the possible interactions between LO and COX pathways in cancer cells. In fact, 12-LO and 15-LO are also expressed in cancer cells, although at a lower frequency than COX-2 and 5-LO. 12-LO has actions similar to 5-LO and COX-2, since it stimulates proliferation and may be proangiogenic (90), whereas 15-LO isoforms may have opposite effects on cancer cells, being the isoform 1 stimulatory and the isoform 2 inhibitory of cancer cell proliferation (91). Therefore, an ideal cancer treatment targeted to the regulation of arachidonic metabolism should block COX-2, 5-LO, 12-LO, and 15-LO-1 without altering or even inducing 15-LO-2. No drug that recapitulates these capabilities is currently available, although combined COX/5-LO inhibitors have been obtained. The best-characterized are E34122 (92), S-2474 (93), tryptanthrin (94), licofelone (ML-3000) (95), and a recently synthesized methoxytetrahydropyran derivative (96). These drugs have been tested in vitro and in animal models of inflammatory disease with encouraging results. Licofelone is now in phase III clinical trials. Compared with single inhibitors, this class of drug has the advantage of an improved anti-inflammatory action associated with a reduction in side effects (97). These molecules have not yet been used to treat cancer patients, although in vitro evidence of the role played by COX-2 and 5-LO in cancer progression would justify such a therapeutic approach. 5-LO inhibitors are also available for clinical use (98). They could be administered in association with NSAIDs to achieve a more extensive block of production of arachidonic acid metabolites that may promote cancer progression. It should be pointed out that COX-2 inhibition sensitizes cancer cells to routinely used chemotherapeutic agents (43). A similar effect can be observed with 5-LO inhibition (unpublished results). Thus, dual COX-2/5-LO inhibitors may also help improve the efficacy of conventional anticancer treatments and reduce their side effects. This approach should take into account the possibility that genetic variants of COX-2 and 5-LO may be associated with cancer development and/or resistance to inhibitors. Our current knowledge of pharmacogenetics and pharmacogenomics of arachidonic acid metabolizing enzymes is limited, but research in this field is progressing. It has been reported that a COX-2 variant, Val511Ala, can be associated with a reduced risk of colorectal neoplasia (99). Individuals heterozygous for the A-842G/C50T haplotype of COX-1 are more sensitive to aspirin (100). It is predicted that in the near future selection of cancer patients for treatment with anti-COX-2/5-LO drugs will be also based on genetic analyses of these enzymes.
1992
Vol. 17
November 2003
CONCLUDING REMARKS The involvement of COX-2 and 5-LO in human cancer progression and neo-angiogenesis is now supported by a large body of literature. The frequent colocalization of these enzymes in cancer cells and the striking analogy of their bioactions on cancer cell proliferation suggest that the simultaneous inhibition of these enzymes may represent a novel and promising therapeutic approach to selected types of cancer. The availability of dual COX-2/5-LO inhibitors now makes this approach possible. We thank Prof. Carlo Patrono for helpful comments. This work was supported in part by grants from the Italian Ministry of Research to the Center of Excellence on Aging of the University of Chieti (M.R.) and from Spanish Ministry of Science and Technology SAF2003-00586 (J.C.).
REFERENCES 1.
2. 3.
4.
5.
6.
7.
8. 9. 10.
11.
12. 13.
Xie, W., Chipman, J. G., Robertson, D. L., Erikson, R. L., and Simmons, D. L. (1991) Expression of a mitogen-responsive gene encoding prostaglandin synthase is regulated by mRNA splicing. Proc. Natl. Acad. Sci. USA 88, 2692–2696 Hla, T., and Neilson, K. (1992) Human cyclooxygenase-2 cDNA. Proc. Natl. Acad. Sci. USA 89, 7384 –7388 Chandrasekharan, N. V., Dai, H., Roos, K. L., Evanson, N. K., Tomsik, J., Elton, T. S., and Simmons, D. L. (2002) COX-3, a cyclooxygenase-1 variant inhibited by acetaminophen and other analgesic/antipyretic drugs: cloning, structure, and expression. Proc. Natl. Acad. Sci. USA 99, 13926 –13931 Funk, C. D., Funk, L. B., Kennedy, M. E., Pong, A. S., and Fitzgerald, G. A. (1991) Human platelet/erythroleukemia cell prostaglandin G/H synthase: cDNA cloning, expression and gene chromosomal assignment. FASEB J. 5, 2304 –2312 Tay, A., Squire, J. A., Goldberg, H., and Sckorecki, K. (1994) Assignment of the human prostaglandin-endoperoxide synthase 2 (PTGS2) gene to 1q25 by fluorescence in situ hybridization. Genomics 23, 718 –719 Yokoyama, C., and Tanabe, T. (1989) Cloning of human gene encoding prostaglandin endoperoxide synthase and primary structure of the enzyme. Biochem. Biophys. Res. Commun. 165, 888 – 894 Jones, D. A., Carlton, D. P., McIntyre, T. M., Zimmerman, G. A., and Prescott, S. M. (1993) Molecular cloning of human prostaglandin endoperoxide synthase type II and demonstration of expression in response to cytokines. J. Biol. Chem. 268, 9049 –9054 Tanabe, T., and Tohnai, N. (2002) Cyclooxygenase isozymes and their gene structures and expression. Prostaglandins Other Lipid Mediat. 68-69, 95–114 Morita, I. (2002) Distinct functions of COX-1 and COX-2. Prostaglandins Other Lipid Mediat. 68-69, 165–175 Rocca, B., Secchiero, P., Ciabattoni, G., Ranelletti, F. O., Catani, L., Guidotti, L., Melloni, E., Maggiano, M., Zauli, G., and Patrono, C. (2001) Cyclooxygenase-2 expression is induced during human megakaryopoiesis and characterizes newly formed platelets. Proc. Natl. Acad. Sci. USA 99, 7634 –7639 Spencer, A. G., Woods, J. W., Arakawa, T., Singer, I. I., and Smith, W. L. (1998) Subcellular localization of prostaglandin endoperoxide H synthases-1 and –2 by immunoelectron microscopy. J. Biol. Chem. 273, 9886 –9893 FitzGerald, G., and Patrono, C. (2001) The Coxibs, selective inhibitors of cyclooxygenase-2. N. Engl. J. Med. 345, 433– 442 Kozak, K. R., Rowlinson, S. W., and Marnett, L. J. (2000) Oxygenation of the endocannabinoid 2-arachidonylglycerol to glyceryl prostaglandins by cyclooxygenase-2. J. Biol. Chem. 275, 33744 –33749
The FASEB Journal
ROMANO AND CLA`RIA
14. 15.
16. 17. 18.
19.
20. 21.
22.
23.
24.
25.
26. 27.
28. 29.
30.
31.
32.
Cla`ria, J., and Serhan, C. N. (1995) Aspirin triggers previously undescribed bioactive eicosanoids by human endothelial cell– leukocyte interactions. Proc. Natl. Acad. Sci. USA 92, 9475–9479 Serhan, C. N., Hong, S., Gronert, K., Colgan, S. P., Devchand, P. R., Mirick, G., and Moussignac, R. L. (2002) Resolvins: a family of bioactive products of omega-3 fatty acid transformation circuits initiated by aspirin treatment that counter proinflammation signals. J. Exp. Med. 196, 1025–1037 Funk, C. D. (2001) Prostaglandins and leukotrienes: advances in eicosanoid biology. Science 294, 1871–1875 Smith, W. L., DeWitt, D. L., and Garavito, R. M. (2000) Cyclooxygenases: structural, cellular and molecular biology. Annu. Rev. Biochem. 69, 145–182 Hecker, M., Foegh, M. L., and Ramwell, P. W. (1995) The eicosanoids: Prostaglandins, Thromboxanes, Leukotrienes and related compounds. In Basic and Clinical Pharmacology (Katzung, B. G., ed) pp. 290 –304, Appleton & Lange, Norwalk, CT Chulada, P. C., Thompson, M. B., Mahler, J. F., Doyle, C. M., Gaul, B. W., Lee, C., Tiano, H. F., Morham, S. G., Smithies, O., and Langenbach, R. (2000) Genetic disruption of Ptgs-1, as well as of Ptgs-2, reduces intestinal tumorigenesis in Min mice. Cancer Res. 60, 4705– 4708 Rigas, B., Goldman, I. S., and Levine, L. (1993) Altered eicosanoid levels in human colon cancer. J. Lab. Clin. Med. 122, 518 –523 Rao, C. V., Simi, B., Wynn, T. T., Garr, K., and Reddy, B. S. (1996) Modulating effect of amount and types of dietary fat on colonic mucosal phospholipase A2, phosphatidylinositol-specific phospholipase C activities and cyclooxygenase metabolite formation during different stages of colon tumor promotion in male F34 rats. Cancer Res. 56, 532–537 Eberhart, C. E., Coffey, R. J., Radhika, A., Giardello, F. M., Ferrenbach, S., and DuBois, R. N. (1994) Up-regulation of cyclooxygenase 2 gene expression in human colorectal adenomas and adenocarcinomas. Gastroenterology 107, 1183–1188 Kutchera, W., Jones, D., Matsumani, N., Groden, J., McIntyre, T. M., Zimmerman, G. A., White, R. L., and Prescott, S. M. (1996) Prostaglandin H synthase 2 is expressed abnormally in human colon cancer: evidence for a transcriptional effect. Proc. Natl. Acad. Sci. USA 93, 4816 – 4820 Muller-Decker, K., Albert, C., Lukanov, T., Winde, G., Marks, F., and Furstenberger, G. (1999) Cellular localization of cyclooxygenase isozymes in Crohn's disease and colorectal cancer. Int. J. Colorectal Dis. 14, 212–218 Bamba, H., Ota, S., Kato, A., Adachi, A., Itoyama, S., and Matsuzaki, F. (1999) High expression of cyclooxygenase-2 in macrophages of human colonic adenoma. Int. J. Cancer 83, 470 – 475 Vadlamudi, R., Mandal, M., Adam, L., Steinbach, G., Mendelsohn, J., and Kumar, R. (1999) Regulation of cyclooxygenase-2 pathway by HER-2 receptor. Oncogene 18, 305–314 Murono, S., Inoue, H., Tanabe, T., Joab, I., Yoshizaki, T., Furukawa, M., and Pagano, J. S. (2001) Induction of cyclooxygenase-2 by Epstein-Barr virus latent membrane protein 1 is involved in vascular endothelial growth factor production in nasopharyngeal carcinoma cells. Proc. Natl. Acad. Sci. USA 98, 6905– 6910 Tsujii, M., and DuBois, R. N. (1995) Alterations in cellular adhesion and apoptosis in epithelial cells overexpressing prostaglandin endoperoxide synthetase 2. Cell 83, 493–501 Qiao, L., Kozoni, V., Tsioulas, G. J., Koutsos, M. I., Hanif, R., Shiff, S. J., and Rigas, B. (1995) Selected eicosanoids increase the proliferation rate of human colon carcinoma cell lines and mouse colonocytes in vivo. Biochim. Biophys. Acta 128, 215–223 Muller-Decker, K., Neufang, G., Berger, I., Neumann, M., Marks, F., and Furstenberger, G. (2002) Transgenic cyclooxygenase-2 overexpression sensitizes mouse skin for carcinogenesis. Proc. Natl. Acad. Sci. USA 99, 12483–12488 Oshima, M., Dinchuk, J. E., Kargman, S. L., Oshima, H., Hancock, B., Kwong, E., Trzaskos, J. M., Evans, J. F., and Taketo, M. M. (1996) Suppression of intestinal polyposis in Apc delta716 knockout mice by inhibition of cyclooxygenase 2 (COX-2). Cell 87, 803– 809 Sheng, H., Shao, J., Kirkland, S. C., Isakson, P., Coffey, R. J., Morrow, J., Beauchamp, R. D., and DuBois, R. N. (1997)
COX-2 AND 5-LO IN CANCER
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45. 46.
47. 48.
49.
Inhibition of human colon cancer cell growth by selective inhibition of cyclooxygenase-2. J. Clin. Invest. 99, 2254 –2259 Elder, D. J., Halton, D. E., Hague, A., and Paraskeva, C. (1997) Induction of apoptotic cell death in human colorectal carcinoma cell lines by a cyclooxygenase-2 (COX-2)-selective nonsteroidal anti-inflammatory drug: independence from COX-2 protein expression. Clin. Cancer Res. 3, 1679 –1683 Piazza, G. A., Rahm, A. K., Finn, T. S., Fryer, B. H., Li, H., Stoumen, A. L., Pamukcu, R., and Ahnen, D. J. (1997) Apoptosis primarily accounts for the growth-inhibitory properties of sulindac metabolites and involves a mechanism that is independent of cyclooxygenase inhibition, cell cycle arrest, and p53 induction. Cancer Res. 57, 2452–2459 Thun, M. J., Henley, S. J., and Patrono, C. (2002) Nonsteroidal anti-inflammatory drugs as anticancer agents: mechanistic, pharmacologic and clinical issues. J. Natl. Cancer Inst. 94, 252–266 Rigau, J., Pique´ , J. M., Rubio, E., Planas, R., Tarrech, J. M., and Bordas, J. M. (1991) Effects of long-term sulindac therapy on colonic polyposis. Ann. Intern. Med. 115, 952–954 Steinbach, G., Lynch, P. M., Phillips, R. K., Wallace, M. H., Hawk, E., Gordon, G. B., Wakabayashi, N., Saunders, B., Shen, Y., Fujimura, T., et al. (2000) The effect of celecoxib, a cyclooxygenase-2 inhibitor in familial adenomatous polyposis. N. Engl. J. Med. 342, 1946 –1952 Kawamori, T., Rao, C. V., Seibert, K., and Reddy, B. S. (1998) Chemopreventive activity of celecoxib, a specific cyclooxygenase-2 inhibitor, against colon carcinogenesis. Cancer Res. 58, 409 – 412 Oshima, M., Murai, N., Kargman, S., Arguello, M., Luk, P., Kwong, E., Taketo, M. M., and Evans, J. F. (2001) Chemoprevention of intestinal polyposis in the APC(delta)716 mouse by rofecoxib, a specific cyclooxygenase-2 inhibitor. Cancer Res. 61, 1733–1740 Koki, A. T., Khan, N. K., Woerner, B. M., Seibert, K., Harmon, J. L., Dannenberg, A. J., Soslow, R. A., and Masferrer, J. L. (2002) Characterization of cyclooxygenase-2 (COX-2) during tumorigenesis in human epithelial cancers: evidence for potential clinical utility of COX-2 inhibitors in epithelial cancer. Prostaglandins Leukot. Essent. Fatty Acids 66, 13–18 Chan, G., Boyle, J. O., Yang, E. K., Zhang, F., Sacks, P. G., Shah, J. P., Edelstein, D., Soslow, R. A., Koki, A. T., Woerner, B. M., et al. (1999) Cyclooxygenase-2 expression is up-regulated in squamous cell carcinoma of the head and neck. Cancer Res. 59, 991–994 Tucker, O. N., Dannenberg, A. J., Yang, E. K., Zhang, F., Teng, L., Daly, J. M., Soslow, J. A., Masferrer, J. L., Woerner, B. M., Koki, A. T., et al. (1999) Cyclooxygenase-2 expression is up-regulated in human pancreatic cancer. Cancer Res. 59, 987–990 Trifan, O. C., Durham, W. F., Salazar, V. S., Horton, J., Levine, B. D., Zweifel, B. S., Davis, T. W., and Masferrer, J. L. (2002) Cyclooxygenase-2 inhibition with celecoxib enhances antitumor efficacy and reduces diarrhea side effect of CPT-11. Cancer Res. 62, 5778 –5784 Han, J. A., Kim, J.-I. I., Ongusaha, P. P., Hwang, D. H., Ballou, L. R., Mahale, A., Aaronson, S. A., and Lee, S. W. (2002) p53-mediated induction of Cox-2 counteracts p53- or genotoxic stress-induced apoptosis. EMBO J. 21, 5635–5644 Prescott, S. M. (2000) Is cyclooxygenase-2 the alpha and the omega in cancer? J. Clin. Invest. 105, 1511–1594 Tsujii, M., Kawano, S., Tsuji, S., Sawaoka, H., Hori, M., and DuBois, R. N. (1998) Cyclooxygenase regulates angiogenesis induced by colon cancer cells. Cell 93, 705–716 Williams, C. S., Tsujii, M., Reese, J., Dey, S. K., and DuBois, R. N. (2000) Host cyclooxygenase-2 modulates carcinoma growth. J. Clin. Invest. 105, 1589 –1594 Fujita, H., Koshida, K., Keller, E. T., Takahashi, Y., Yoshimito, T., Namiki, M., and Mizokami, A. (2002) Cyclooxygenase-2 promotes prostate cancer progression. Prostate 53, 232–240 Kirkpatrick, K., Ogunkolade, W., Elkak, A., Bustin, S., Jenkins, P., Ghilchik, M., and Mokbel, K. (2002) The mRNA expression of cyclo-oxygenase-2 (COX-2) and vascular endothelial growth factor (VEGF) in human breast cancer. Curr. Med. Res. Opin. 18, 237–241
1993
50.
51.
52.
53.
54.
55. 56. 57.
58.
59. 60. 61. 62. 63.
64. 65. 66.
67.
68.
1994
Hoper, M. M., Voelkel, N. F., Bates, T. O., Allard, J. D., Horan, M., Shepherd, D., and Tuder, R. M. (1997) Prostaglandins induce vascular endothelial growth factor in a human monocytic cell line and rat lungs via cAMP. Am. J. Respir. Cell Mol. Biol. 17, 748 –756 Liu, X. H., Kirschenbaum, A., Lu, M., Yao, S., Dosoretz, A., Holland, J. F., and Levine, A. C. (2002) Prostaglandin E2 induces hypoxia-inducible factor-1alpha stabilization and nuclear localization in a prostate cancer cell line. J. Biol. Chem. 277, 50081–50086 Seed, M. P., Brown, J. R., Freemantle, C. N., Papworth, J. L., Colville-Nash, P. R., Willis, D., Somerville, K. W., Asculai, S., and Willoughby, D. A. (1997) The inhibition of colon-26 adenocarcinoma development and angiogenesis by topical diclofenac in 2.5% hyaluronan. Cancer Res. 57, 1625–1629 Masferrer, J. L., Leahy, K. M., Koki, A. T., Zweifel, B. S., Settle, S. L., Woerner, B. M., Edwards, D. A., Flickinger, A. G., Moore, R. J., and Seibert, K. (2000) Antiangiogenic and antitumor activities of cyclooxygenase-2 inhibitors. Cancer Res. 60, 1306 – 1311 Borgeat, P., Hamberg, M., and Samuelsson, B. (1976) Transformation of arachidonic acid and homo-gamma-linolenic acid by rabbit polymorphonuclear leukocytes. Monohydroxy acids from novel lipoxygenases. J. Biol. Chem. 251, 7816 –7820 Funk, C. D., Hoshiko, S., Matsumoto, T., Radmark, O., and Samuelsson, B. (1989) Characterization of the human 5-lipoxygenase gene. Proc. Natl. Acad. Sci. USA 86, 2587–2591 Hoshiko, S., Radmark, O., and Samuelsson, B. (1990) Characterization of the human 5-lipoxygenase gene promoter. Proc. Natl. Acad. Sci. USA 87, 9073–9077 In, K. H., Asano, K., Beier, D., Grobholz, J., Finn, P. W., Silverman, E. K., Silverman, E. S., Collins, T., Fischer, A. R., Keith, T. P., et al. (1997) Naturally occurring mutations in the human 5-lipoxygenase gene promoter that modify transcription factor binding and reporter gene transcription. J. Clin. Invest. 99, 1130 –1137 Brungs, M., Radmark, O., Samuelsson, B., and Steinhilber, D. (1995) Sequential induction of 5-lipoxygenase gene expression and activity in Mono Mac 6 cells by transforming growth factor beta and 1,25-dihydroxyvitamin D3. Proc. Natl. Acad. Sci. USA 92, 107–111 Uhl, J., Klan, N., Rose, M., Entian, K. D., Werz, O., and Steinhilber, D. (2002) The 5-lipoxygenase promoter is regulated by DNA methylation. J. Biol. Chem. 277, 4374 – 4379 Radmark, O., Shimizu, T., Jornvall, H., and Samuelsson, B. (1984) Leukotriene A4 hydrolase in human leukocytes. Purification and properties. J. Biol. Chem. 259, 12339 –12345 Lam, B. K., and Austen, F. K. (2000) Leukotriene C4 synthase. A pivotal enzyme in the biosynthesis of the cysteinyl leukotrienes. Am. J. Respir. Crit. Care Med. 161, S16 –S19 Serhan, C. N., and Romano, M. (1995) Lipoxin biosynthesis and actions: role of the human platelet LX-synthase. J. Lipid Mediat. Cell Signal. 12, 293–306 Dixon, R. A. F., Diehl, R. E., Opas, E., Rands, E., Vickers, P. J., Evans, J. F., Gillard, J. W., and Miller, D. K. (1990) Requirement of a 5-lipoxygenase-activating protein for leukotriene synthesis. Nature (London) 343, 282–284 Werz, O., Klemm, J., Samuelsson, B., and Radmark, O. (2000) 5-Lipoxygenase is phosphorylated by p38 kinase-dependent MAPKAP kinases. Proc. Natl. Acad. Sci. USA 97, 5261–5266 Peters-Golden, M., and Brock, T. G. (2000) Intracellular compartmentalization of leukotriene biosynthesis. Am. J. Respir. Crit. Care Med. 161, S36 –S40 Pouliot, M., McDonald, P. P., Krump, E., Mancini, J. A., McColl, S. R., Weech, P. K., and Borgeat, P. (1996) Colocalization of cytosolic phospholipase A2, 5-lipoxygenase, and 5-lipoxygenase-activating protein at the nuclear membrane of A23187-stimulated human neutrophils. Eur. J. Biochem. 238, 250 –258 Chen, X. S., Zhang, Y. Y., and Funk, C. D. (1998) Determinants of 5-lipoxygenase nuclear localization using green fluorescent protein/5-lipoxygenase fusion proteins. J. Biol. Chem. 273, 31237–31244 Jones, S. M., Luo, M., Healy, A. M., Peters-Golden, M., and Brock, T. G. (2002) Structural and functional criteria reveal a new nuclear import sequence on the 5-lipoxygenase protein. J. Biol. Chem. 277, 38550 –38556
Vol. 17
November 2003
69. 70.
71.
72.
73.
74. 75.
76.
77.
78.
79. 80.
81.
82.
83. 84.
85.
86. 87.
Yokomizo, T., Izumi, T., Chang, K., Takuwa, Y., and Shimizu, T. (1997) A G-protein-coupled receptor for leukotriene B4 that mediates chemotaxis. Nature (London) 387, 620 – 624 Yokomizo, T., Kato, K., Terawaki, K., Izumi, T., and Shimizu, T. (2000) A second leukotriene B(4) receptor, BLT2. A new therapeutic target in inflammation and immunological disorders. J. Exp. Med. 192, 421– 432 Lynch, K. R., O'Neill, G. P., Liu, Q., Im, D. S., Sawyer, N., Metters, K. M., Coulombe, N., Abramovitz, M., Figueroa, D. J., Zeng, Z., et al.. (1999) Characterization of the human cysteinyl leukotriene CysLT1 receptor. Nature (London) 399, 789 –793 Heise, C. E., O'Dowd, B. F., Figueroa, D. J., Sawyer, N., Nguyen, T., Im, D. S., Stocco, R., Bellefeuille, J. N., Abramovitz, M., Cheng, R., et al. (2000) Characterization of the human cysteinyl leukotriene 2 receptor. J. Biol. Chem. 275, 30531–30536 Hosoi, T., Koguchi, Y., Sugikawa, E., Chikada, A., Ogawa, K., Tsuda, N., Suto, N., Tsunoda, S., Taniguchi, T., and Ohnuki, T. (2002) Identification of a novel human eicosanoid receptor coupled to G(i/o). J. Biol. Chem. 277, 31459 –31465 Chen, X. S., Sheller, J. R., Johnson, E. N., and Funk, C. D. (1994) Role of leukotrienes revealed by targeted disruption of the 5-lipoxygenase gene. Nature (London) 372, 179 –182 Bailie, M. B., Standiford, T. J., Laichalk, L. L., Coffey, M. J., Strieter, R., and Peters-Golden, M. (1996) Leukotriene-deficient mice manifest enhanced lethality from Klebsiella pneumonia in association with decreased alveolar macrophage phagocytic and bactericidal activities. J. Immunol. 157, 5221– 5224 Hong, S. H., Avis, I., Vos, M. D., Martinez, A., Treston, A. M., and Mulshine, J. L. (1999) Relationship of arachidonic acid metabolizing enzyme expression in epithelial cancer cell lines to the growth effect of selective biochemical inhibitors. Cancer Res. 59, 2223–2228 Avis, I., Hong, S. H., Martinez, A., Moody, T., Choi, Y. H., Trepel, J., Das, R., Jett, M., and Mulshine, J. L. (2001) Five-lipoxygenase inhibitors can mediate apoptosis in human breast cancer cell lines through complex eicosanoid interactions. FASEB J. 15, 2007–2009 Avis, I. M., Jett, M., Boyle, T., Vos, M. D., Moody, T., Treston, A. M., Martinez, A., and Mulshine, J. L. (1996) Growth control of lung cancer by interruption of 5-lipoxygenase-mediated growth factor signaling. J. Clin. Invest. 97, 806 – 813 Kargman, S., Vickers, P. J., and Evans, J. F. (1992) A23187 induces translocation of 5-lipoxygenase in osteosarcoma cells. J. Cell Biol. 119, 1701–1709 Boado, R. J., Pardridge, W. M., Vinters, H. V., and Black, K. L. (1992) Differential expression of arachidonate 5-lipoxygenase transcripts in human brain tumors: evidence for the expression of a multitranscript family. Proc. Natl. Acad. Sci. USA 89, 9044 –9048 Hennig, R., Ding, X. Z., Tong, W. G., Schneider, M. B., Standop, J., Friess, H., Buchler, M. W., Pour, P. M., and Adrian, T. E. (2002) 5-Lipoxygenase and leukotriene B(4) receptor are expressed in human pancreatic cancers but not in pancreatic ducts in normal tissue. Am. J. Pathol. 161, 421– 428 Romano, M., Catalano, A., Nutini, M., D'Urbano, E., Crescenzi, C., Cla`ria, J., Libner, R., Davi, G., and Procopio, A. (2001) 5-Lipoxygenase regulates malignant mesothelial cell survival: involvement of vascular endothelial growth factor. FASEB J. 15, 2326 –2336 Gupta, S., Srivastava, M., Ahmad, N., Sakamoto, K., Bostwick, D. G., and Mukhtar, H. (2001) Lipoxygenase-5 is overexpressed in prostate adenocarcinoma. Cancer 91, 737–743 Ohd, J. F., Nielsen, C. K., Campbell, J., Landberg, G., Lofberg, H., and Sjolander, A. (2003) Expression of the leukotriene D4 receptor CysLT1 , COX-2, and other cell survival factors in colorectal adenocarcinomas. Gastroenterology 124, 57–70 Tsukada, T., Nakashima, K., and Shirakawa, S. (1986) Arachidonate 5-lipoxygenase inhibitors show potent antiproliferative effects on human leukemia cell lines. Biochem. Biophys. Res. Commun. 140, 832– 836 Ghosh, J., and Myers, C. (1998) Inhibition of arachidonate 5-lipoxygenase triggers massive apoptosis in human prostate cancer cells. Proc. Natl. Acad. Sci. USA 95, 13182–13187 Narumiya, S., and FitzGerald, G. A. (2001) Genetic and pharmacological analysis of prostanoid receptor function. J. Clin. Invest. 108, 25–30
The FASEB Journal
ROMANO AND CLA`RIA
88.
89.
90.
91.
92.
93.
Shureiqi, I., Xu, X., Chen, D., Lotan, R., Morris, J. S., Fischer, S. M., and Lippman, S. M. (2001) Nonsteroidal anti-inflammatory drugs induce apoptosis in esophageal cancer cells by restoring 15-lipoxygenase-1 expression. Cancer Res. 61, 4879 – 4884 Cao, Y., Pearman, A. T., Zimmerman, G. A., McIntyre, T. M., and Prescott, S. M. (2000) Intracellular unesterified arachidonic acid signals apoptosis. Proc. Natl. Acad. Sci. USA 97, 11280 –11285 Nie, D., Hillman, G. G., Geddes, T., Tang, K., Pierson, C., Grignon, D. J., and Honn, K. V. (1998) Platelet-type 12lipoxygenase in a human prostate carcinoma stimulates angiogenesis and tumor growth. Cancer Res. 58, 4047– 4051 His, L. C., Wilson, L. C., and Eling, T. E. (2002) Opposing Effects of 15-Lipoxygenase-1 and -2 Metabolites on MAPK Signaling in Prostate. Alteration in peroxisome proliferatoractivated receptor gamma. J. Biol. Chem. 277, 40549 – 40556 Horizoe, T., Nagakura, N., Chiba, K., Shirota, H., Shinoda, M., Kobayashi, N., Numata, H., Okamoto, Y., and Kobayashi, S. (1998) ER-34122, a novel dual 5-lipoxygenase/cyclooxygenase inhibitor with potent anti-inflammatory activity in an arachidonic acid-induced ear inflammation model. Inflamm. Res. 47, 375–383 Inagaki, M., Tsuri, T., Jyoyama, H., Ono, T., Yamada, K., Kobayashi, M., Hori, Y., Arimura, A., Yasui, K., Ohno, K., et al. (2000) Novel antiarthritic agents with 1,2-isothiazolidine-1,1dioxide (gamma-sultam) skeleton: cytokine suppressive dual inhibitors of cyclooxygenase-2 and 5-lipoxygenase. J. Med. Chem. 43, 2040 –2048
COX-2 AND 5-LO IN CANCER
94.
95. 96.
97.
98. 99.
100.
Danz, H., Baumann, D., and Hamburger, M. (2002) Quantitative determination of the dual COX-2/5-LOX inhibitor tryptanthrin in Isatis tinctoria by ESI-LC-MS. Planta Med. 68, 152–157 Tries, S., Neupert, W., and Laufer, S. (2002) The mechanism of action of the new antiinflammatory compound ML3000: inhibition of 5-LOX and COX-1/2. Inflamm. Res. 51, 135–143 Barbey, S., Goossens, L., Taverne, T., Cornet, J., Choesmel, V., Rouaud, C., Gimeno, G., Yannic-Arnoult, S., Michaux, C., Charlier, C., et al. (2002) Synthesis and activity of a new methoxytetrahydropyran derivative as dual cyclooxygenase2/5-lipoxygenase inhibitor. Bioorg. Med. Chem. Lett. 12, 779 –782 Fiorucci, S., Meli, R., Bucci, M., and Cirino, G. (2001) Dual inhibitors of cyclooxygenase and 5-lipoxygenase. A new avenue in anti-inflammatory therapy? Biochem. Pharmacol. 62, 1433– 1438 Drazen, J. M. (1999) Asthma therapy with agents preventing leukotriene synthesis or action. Proc. Assoc. Am. Physicians 111, 547–559 Lin, H. J., Lakkides, K. M., Keku, T. O., Reddy, S. T., Louie, A. D., Kau, I. H., Zhou, H., Gim, J. S., Ma, H. L., Matthies, C. F., et al. (2002) Prostaglandin H synthase 2 variant (Val511Ala) in African Americans may reduce the risk for colorectal neoplasia. Cancer Epidemiol. Biomarkers 11, 1305–1315 Halushka, M. K., Walker, L. P., and Halushka, P. V. (2003) Genetic variation in cyclooxygenase 1: effects on response to aspirin. Clin. Pharmacol. Ther. 73, 122–130 Received for publication March 17, 2003. Accepted for publication June 11, 2003.
1995
