Inhibition of 5-lipoxygenase by MK886 augments the antitumor activity of celecoxib in human colon cancer cells

Cyclooxygenase (COX)-2 and 5-lipoxygenase (5-LOX) are key enzymes involved in arachidonic acid metabolism. Their products, prostaglandins and leukotrienes, are involved in colorectal tumor development. We aimed at evaluating whether combined blocking of the COX-2 and 5-LOX pathways might have additive antitumor effects in colorectal cancer. The expression/activity of COX-2 and 5-LOX were assessed in 24 human colorectal cancer specimens. The effects of the COX-2 inhibitor celecoxib and the 5-LOX inhibitor MK886 on prostaglandin E(2) and cysteinyl leukotriene production, tumor cell proliferation, cell apoptosis, and Bcl-2/Bax expression were evaluated in the Caco-2 and HT29 colon cancer cells. We also investigated the effect of the enzymatic inhibition on mitochondrial membrane depolarization, one of the most important mechanisms involved in ceramide-induced apoptosis. Up-regulation of the COX-2 and 5-LOX pathways was found in the tumor tissue in comparison with normal colon mucosa. Inhibition of either COX-2 or 5-LOX alone resulted in activation of the other pathway in colon cancer cells. Combined treatment with 10 micromol/L celecoxib and MK886 could prevent this activation and had additive effects on inhibiting tumor cell proliferation, inducing cell apoptosis, decreasing Bcl-2 expression, increasing Bax expression, and determining mitochondrial depolarization in comparison with treatment with either inhibitor alone. The administration of the ceramide synthase inhibitor fumonisin B1 could prevent some of these antineoplastic effects. In conclusion, our study showed that inhibition of 5-LOX by MK886 could augment the antitumor activity of celecoxib in human colorectal cancer.     

Biochemistry of cyclooxygenase (COX)-2 inhibitors and molecular pathology of COX-2 in neoplasia

Several types of human tumors overexpress cyclooxygenase (COX) -2 but not COX-1, and gene knockout transfection experiments demonstrate a central role of COX-2 in experimental tumorigenesis. COX-2 produces prostaglandins that inhibit apoptosis and stimulate angiogenesis and invasiveness. Selective COX-2 inhibitors reduce prostaglandin synthesis, restore apoptosis, and inhibit cancer cell proliferation. In animal studies they limit carcinogen-induced tumorigenesis. In contrast, aspirin-like nonselective NSAIDs such as sulindac and indomethacin inhibit not only the enzymatic action of the highly inducible, proinflammatory COX-2 but the constitutively expressed, cytoprotective COX-1 as well. Consequently, nonselective NSAIDs can cause platelet dysfunction, gastrointestinal ulceration, and kidney damage. For that reason, selective inhibition of COX-2 to treat neoplastic proliferation is preferable to nonselective inhibition. Selective COX-2 inhibitors, such as meloxicam, celecoxib (SC-58635), and rofecoxib (MK-0966), are NSAIDs that have been modified chemically to preferentially inhibit COX-2 but not COX-1. For instance, meloxicam inhibits the growth of cultured colon cancer cells (HCA-7 and Moser-S) that express COX-2 but has no effect on HCT-116 tumor cells that do not express COX-2. NS-398 induces apoptosis in COX-2 expressing LNCaP prostate cancer cells and, surprisingly, in colon cancer S/KS cells that does not express COX-2. This effect may due to induction of apoptosis through uncoupling of oxidative phosphorylation and down-regulation of Bcl-2, as has been demonstrated for some nonselective NSAIDs, for instance, flurbiprofen. COX-2 mRNA and COX-2 protein is constitutively expressed in the kidney, brain, spinal cord, and ductus deferens, and in the uterus during implantation. In addition, COX-2 is constitutively and dominantly expressed in the pancreatic islet cells. These findings might somewhat limit the use of presently available selective COX-2 inhibitors in cancer prevention but will probably not deter their successful application for the treatment of human cancers.     

Selective inhibitors of MEK1/ERK44/42 and p38 mitogen-activated protein kinases potentiate apoptosis induction by sulindac sulfide in human colon carcinoma cells

The nonsteroidal anti-inflammatory drug (NSAID) sulindac prevents experimental colon cancer and can regress precancerous polyps in humans. Sulindac sulfide inhibits cyclooxygenase (COX)-mediated prostaglandin synthesis and retards the growth of cultured colon cell lines primarily by inducing apoptosis. Given the known role of mitogen-activated protein kinase (MAPK) in signal transduction and the regulation of cell survival and death, we determined the effect of sulindac sulfide on MAPK activation, COX-2 expression, and apoptosis induction in HCA-7 human colon cancer cells. Sulindac sulfide treatment was associated with activation of ERKp44/42 and p38 MAPK in a dosage- and time-dependent manner, and also activated upstream MEK. Similar results were seen in HCT-15 cells and also with the selective COX-2 inhibitor NS398. ERKp44/42 and p38 activation were accompanied by an induction of COX-2 protein expression. Selective inhibitors of sulindac sulfide-induced ERKp44/42 (PD98059) and p38 MAPK (SB203580) activation also suppressed the induction of COX-2 by this NSAID. Furthermore, both MAPK inhibitors significantly augmented sulindac sulfide-induced apoptosis, as did suppression of constitutive COX-2 using antisense oligonucleotides. In conclusion, MEK/ERK and p38 MAPK activation mediate COX-2 induction by sulindac sulfide. Selective inhibitors of these MAPKs potentiate apoptosis induction by this NSAID, suggesting a novel strategy for the prevention or treatment of colorectal cancer.     

塞来昔布联合 PDTC 对人结肠癌细胞 HT-29 的抑制增殖和促凋亡作用及其机制

目的研究塞来昔布联合吡咯烷二硫氨基甲酸（PDTC）对人结肠癌细胞HT-29增殖、凋亡的影响及其对COX-2、NF-κB、Caspase-3基因表达的影响,探讨塞来昔布联合用药抗肿瘤的机制。方法用不同浓度的塞来昔布（30、60、120、240μmol／L）（单药组）以及不同浓度塞来昔布联合不同浓度的PDTC（50、100μmol／L）（联合组）分别处理人结肠癌细胞,采用CCK-8法检测细胞的增殖情况,流式细胞术分析细胞凋亡情况,实时荧光定量PCR检测各组细胞COX-2、NF-κB、Caspase-3表达的变化。结果塞来昔布单药组对结肠癌细胞具有抑制增殖、促进凋亡作用,其作用随着药物浓度、给药时间的增加而增强（P均〈0．05）;同时检测到COX-2、NF-κBKBmRNA的表达降低（P均〈0．05）,Caspase-3表达升高（P〈0．05）,且具有浓度依赖性;联合组较同一塞来昔布浓度的单药组上述作用更明显（P均〈0．05）。结论塞来昔布单药组和联合组均能抑制人结肠癌细胞的增殖,促进其凋亡;联合组作用强于单药组;其机制可能与COX-2、NF-κB的下调和Caspase-3表达上调有关。     

塞来昔布对人白血病细胞株HL-60细胞增殖及凋亡的影响及其作用机制

本研究旨在探讨塞来昔布（celecoxib）对人急性髓系白血病细胞株HL-60细胞增殖、凋亡的影响及其可能的作用机制。不同浓度塞来昔布作用于HL-60细胞24h后,CCK-8法测定细胞增殖活性,流式细胞技术分析细胞凋亡及细胞周期分布的变化,定量RT—PCR的方法检测细胞周期蛋白DJ、EI及COX-2mRNA的表达。结果表明,不同浓度塞来昔布作用于HL-60细胞24h后,细胞增殖明显受抑,且呈-定的浓度依赖性（r=0．955）,24h的IC50值为63．037μmol／L。塞来昔布可诱导HL-60细胞的凋亡,也呈剂量依赖性（r=0．988）。塞来昔布可使HL-60细胞明显阻滞于G0／G1期,可下调cyclinD1、cyclinE1mRNA的表达。塞来昔布可使细胞COX-2mRNA表达水平降低。结论：塞来昔布呈浓度依赖性抑制HL-60细胞增殖,并可能通过下调cyclinD1、cyclinE1的表达引起细胞G0／G1,期阻滞,下调COX-2的表达诱导细胞凋亡。     

Inhibition of human colon cancer cell growth by selective inhibition of cyclooxygenase-2.

A considerable amount of evidence collected from several different experimental systems indicates that cyclooxygenase-2 (COX-2) may play a role in colorectal tumorigenesis. Large epidemiologic studies have shown a 40-50% reduction in mortality from colorectal cancer in persons taking aspirin or other nonsteroidal antiinflammatory drugs on a regular basis. One property shared by all of these drugs is their ability to inhibit COX, a key enzyme in the conversion of arachidonic acid to prostaglandins. Two isoforms of COX have been characterized, COX-1 and COX-2. COX-2 is expressed at high levels in intestinal tumors in humans and rodents. In this study, we selected two transformed human colon cancer cell lines for studies on the role of COX-2 in intestinal tumorigenesis. We evaluated HCA-7 cells which express high levels of COX-2 protein constitutively and HCT-116 cells which lack COX-2 protein. Treatment of nude mice implanted with HCA-7 cells with a selective COX-2 inhibitor (SC-58125), reduced tumor formation by 85-90%. SC-58125 also inhibited colony formation of cultured HCA-7 cells. Conversely, SC-58125 had no effect on HCT-116 implants in nude mice or colony formation in culture. Here we provide evidence that there may be a direct link between inhibition of intestinal cancer growth and selective inhibition of the COX-2 pathway.     

环氧合酶2抑制剂塞来昔布对结肠癌多药耐药逆转作用的研究

目的 探讨环氧合酶2(COX-2)抑制剂塞来昔布对结肠癌多药耐药(MDR)的逆转作用.方法 在结肠癌多药耐药细胞株colo320/5-FU中,应用四甲基偶氮唑蓝(MTT)方法检测塞来昔布时5-氟尿嘧啶(5-FU)的耐药逆转倍数;反转录-聚合酶链反应(RT-PCR)方法检测耐药基因的变化;免疫组织化学法检测细胞膜跨膜蛋白p-170(P-gP)的表达.结果 MTT结果显示塞来昔布对结肠癌细胞的耐药产生明显的逆转作用(F=2285.660,P＜0.01),其逆转倍数分别为1.70,3.80,8.48,且呈浓度依赖性.RT-PCR结果显示塞来昔布明显抑制多药耐药基因1(MDR1)mRNA的表达(F=986.776,P＜0.01),且呈浓度依赖性减低,各浓度组之间差异有统计学意义(P＜0.01).免疫荧光结果显示,细胞膜P-gp荧光强度随着塞来昔布浓度的逐渐增高而减弱.结论 选择性COX-2抑制剂塞来昔布对多药耐药细胞株colo320/5-FU具有明显逆转作用,在非细胞毒剂量范围内呈现剂量依赖性,初步机制可能涉及干预多种转录因子的表达而下调MDR1,继而阻滞细胞周期及增加细胞凋亡.     

Cyclooxygenase-2 dependent and independent antitumor effects induced by celecoxib in urinary bladder cancer cells

Transitional cell carcinoma of the urinary bladder is the second most common genitourinary malignancy in people in the United States. Cyclooxygenase-2 (COX-2) is overexpressed in bladder cancer. COX-2 inhibitors have had antitumor activity against bladder cancer, but the mechanisms of action are unclear. Clinically relevant concentrations of COX-2 inhibitors fail to inhibit proliferation in standard in vitro assays. In pilot experiments, different culture conditions [standard monolayer, modified monolayer, soft agar, collagen, and poly(2-hydroxyethyl methacrylate)-coated plates] were assessed to determine conditions suitable for the study of COX inhibitor growth-inhibitory effects. This was followed by studies of the effects of clinically relevant concentrations of a selective COX-2 inhibitor (celecoxib) on urinary bladder cancer cell lines (HT1376, TCCSUP, and UMUC3). Celecoxib (相似文献   

EFFECTS OF p53 GENE THERAPY COMBINED WITH CYCLOOXYGENASE-2 INHIBITOR ON CYCLOOXYGENASE-2 GENE EXPRESSION AND GROWTH INHIBITION OF HUMAN LUNG CANCER CELLS

1 INTRODUCTIONCOXis the key enzyme involved in the synthesis of prostanoids,a collective termfor the PGs andthromboxanes.Of the two major isoforms of the COXenzyme,COX-1 is ubiquitous and constitutively ex-pressedin virtually all normal tissues.In contras…     

塞来昔布抑制人结肠癌细胞Caco-2细胞增殖及其分子机制

目的研究塞来昔布在体外抑制人结肠癌细胞Caco-2生长增殖及其抗肿瘤的相关分子机制。方法体外培养人结肠癌细胞Caco-2,分组为正常组(无任何干预)及塞来昔布组。四甲基偶氮唑盐(MTT)法检测塞来昔布在相同浓度下,不同时间对于胃癌细胞增殖的影响,并计算半数抑制浓度(IC50)值;反转录聚合酶链式反应(RT-PCR)法检环氧化酶-2(COX-2)、基质金属蛋白酶9(MMP-9)的mRNA的表达影响。结果 MTT结果显示:相同干预浓度塞来昔布抑制人胃癌细胞增殖,其24 h,48 h,72 h的IC50分别为:99.519±10.355μmol/L、71.546±6.446μmol/L、59.622±15.999μmol/L;RT-PCR结果显示:人结肠癌细胞Caco-2正常对照组及塞来昔布干预组COX-2mRNA灰度值分别为:0.808±0.021,0.101±0.002(t=19.037,P=0.000);MMP-9 mRNA灰度值分别为:0.798±0.031,0.190±0.002(t=18.987,P=0.002)。结论塞来昔布可能通过抑制COX-2、MMP-9的mRNA的表达,从而抑制结肠癌细胞增殖。     

The cyclooxygenase-2 inhibitor celecoxib blocks phosphorylation of Akt and induces apoptosis in human cholangiocarcinoma cells

The expression of cyclooxygenase (COX)-2 is increased in human cancers including cholangiocarcinoma. This study was designed to evaluate the effect and mechanisms of the selective COX-2 inhibitor celecoxib in the growth control of human cholangiocarcinoma cells. Immunohistochemical analysis using human cholangiocarcinoma tissues showed increased levels of COX-2 as well as phospho-Akt (Thr (308)), a protein kinase activated by COX-2-mediated prostaglandins, in human cholangiocarcinoma cells. Treatment of cultured human cholangiocarcinoma cells (HuCCT1, SG231, and CCLP1) with celecoxib resulted in a dose- and time-dependent reduction of cell viability. Fluorescence microscopy, Western blot, and caspase activity assays demonstrated that celecoxib induced morphological features of apoptosis, activation of caspase-9 and caspase-3, and release of cytochrome c. The celecoxib-induced cell death was significantly blocked by N-benzyloxy-carbonyl-Val-Ala-Asp-fluoromethylketone, a wide-spectrum caspase inhibitor. Furthermore, cholangiocarcinoma cells treated with celecoxib showed significant reduction of Akt phosphorylation, whereas the levels of Bcl-2 and Bax were not altered. Inhibition of Akt activation by LY294002 significantly decreased the viability of human cholangiocarcinoma cells. These findings suggest that celecoxib inhibits cholangiocarcinoma growth partly through induction of apoptosis and inhibition of Akt phosphorylation.     

Celecoxib acts in a cyclooxygenase-2-independent manner and in synergy with emodin to suppress rat cholangiocarcinoma growth in vitro through a mechanism involving enhanced Akt inactivation and increased activation of caspases-9 and -3

Emodin, a tyrosine kinase inhibitor, effectively blocked tyrosine phosphorylation of p185(neu) overexpressed in cultured rat C611B cholangiocarcinoma (ChC) cells and in neu-transformed WB-F344 rat-liver epithelial stem-like cells (WBneu cells). Celecoxib, a cyclooxygenase-2 inhibitor, markedly decreased prostaglandin (PG) levels overproduced by these respective neoplastically transformed liver cell types but was without effect in inhibiting PG production by untransformed WB-F344 cells that do not express detectable cyclooxygenase-2 protein. Notably, in combination, emodin (30 micro M) and celecoxib (35 micro M) acted synergistically to significantly suppress anchorage-dependent and -independent growth of C611B ChC cells and of WBneu cells over treatments with either agent alone. This prominent suppression of cell growth correlated with significant increases in the activation of caspases-9 and -3 and induction of apoptosis in the combination-treated cells, which was associated with an enhanced suppression of Akt activation. Here it is important to note that the concentration of celecoxib needed to suppress growth and induce apoptosis in the C611B and WBneu cells was markedly higher than that needed to effectively inhibit PG production by these malignant cell types. Thus, our data indicate that celecoxib is acting independently of its ability to inhibit cyclooxygenase-2 activity in suppressing growth of C611B and WBneu cells in vitro. Furthermore, our findings strongly suggest that increased inhibition of the antiapoptotic kinase Akt activation produced by the emodin/celecoxib combination treatment plays a key role in the mechanism by which this drug combination acts to enhance cell growth suppression and apoptosis in cultured C611B ChC cells and WBneu cells.     

The rice bran constituent tricin potently inhibits cyclooxygenase enzymes and interferes with intestinal carcinogenesis in ApcMin mice

While brown rice is a staple dietary constituent in Asia, rice consumed in the Western world is generally white, obtained from brown rice by removal of the bran. Rice bran contains the flavone tricin, which has been shown to inhibit colon cancer cell growth. We tested the hypothesis that tricin interferes with adenoma formation in the Apc(Min) mouse. Mice received tricin (0.2%) in their American Institute of Nutrition 93G diet throughout their postweaning life span (4-18 weeks). Consumption of tricin reduced numbers of intestinal adenomas by 33% (P < 0.05) compared with mice on control diet. We explored whether tricin may exert its effect via inhibition of cyclooxygenase (COX) enzymes. Its effect on COX activity was assessed in purified enzyme preparations in vitro and its ability to reduce prostaglandin E(2) (PGE(2)) levels in human colon-derived human colon epithelial cell (HCEC) and HCA-7 cells in vitro and in Apc(Min) mice in vivo. Tricin inhibited activity of purified COX-1 and COX-2 enzyme preparations with IC(50) values of approximately 1 micromol/L. At 5 micromol/L, it reduced PGE(2) production in HCEC or HCA-7 cells by 36% (P < 0.01) and 35% (P < 0.05), respectively. COX-2 expression was reduced by tricin weakly in HCEC and unaffected in HCA-7 cells. PGE(2) levels in the small intestinal mucosa and blood of Apc(Min) mice that had received tricin were reduced by 34% (P < 0.01) and 40% (P < 0.05), respectively, compared with control mice. The results suggest that tricin should be further evaluated as a putative colorectal cancer chemopreventive agent.     

Cyclooxygenase inhibitors in urinary bladder cancer: in vitro and in vivo effects

More than 14,000 people die from invasive transitional cell carcinoma (TCC) of the urinary bladder yearly in the United States. Cyclooxygenase (COX)-inhibiting drugs are emerging as potential antitumor agents in TCC. The optimal in vitro or in vivo systems to investigate COX inhibitor antitumor effects have not been defined. The purpose of this study was to determine COX-1 and COX-2 expression and antitumor effects of COX inhibitors in human TCC cell lines (HT1376, RT4, and UMUC3 cells) and xenografts derived from those cell lines. COX-2 expression (Western blot, immunocytochemistry) was high in HT1376, modest in RT4, and absent in UMUC3 cells in vitro. Similarly, COX-2 expression was noted in RT4 but not UMUC3 xenografts. COX-2 expression in HT1376 xenografts was slightly lower than that observed in vitro. None of four COX inhibitors evaluated (celecoxib, piroxicam, valeryl salicylate, and NS398) reduced TCC growth in standard in vitro proliferation assays at concentrations that could be safely achieved in vivo (< or =5 micromol/L). Higher celecoxib concentrations (> or =50 micromol/L) inhibited proliferation and induced apoptosis in all three cell lines. Celecoxib or piroxicam treatment in athymic mice significantly delayed progression of HT1376 xenografts, which express COX-2, but not UMUC3 xenografts that lack COX-2 expression. In conclusion, standard in vitro assays were not useful in predicting COX inhibitor antitumor effects observed in vivo. Athymic mice bearing TCC xenografts provide a useful in vivo system for COX inhibitor studies. Results of this study provide justification for further evaluation of COX inhibitors as antitumor agents against TCC.     

Selective inhibition of cyclooxygenase-2 suppresses the growth of pancreatic cancer cells in vitro and in vivo

Cyclooxygenase-2 (COX-2), a prostaglandin synthetase, is involved in development of certain tumors. We therefore analyzed COX-2 expression in pancreatic cancer tissues (53 samples) and Panc-1 human pancreatic cancer cells by immunohistochemistry, RT-PCR and western-blotting analyses. Also, immunohistochemistry of proliferating cell nuclear antigen (PCNA) was performed. We found expression of COX-2 was dramatically upregulated in 36 of 53 cases (67.9%) and the expression of COX-2 was associated with the diameter (> 3 cm) of the tumors (p < 0.05), but not with the age, gender, tumor location, differentiation, lymph-node metastases and TNM stage. The positivity rate of PCNA expression in the pancreatic cancer cells of the COX-2 positive group (32.88 +/- 13.26%) was significantly higher than that in the COX-2 negative group (24.56 +/- 11.51%) (p < 0.05). Then we investigated the effect of selective inhibitors of COX-2 (NS398 and celecoxib) on proliferation of Panc-1 cells by 3-(4,5 dimethyl-2-thiazolyl)-2.5-diphenyl-2H-tetrazolium bromide (MTT) assay. Either NS398 or celecoxib suppressed proliferation of Panc-1 cells dose-dependently in vitro. Furthermore, Panc-1 cells were implanted into nude mice, and celecoxib was administrated orally with feed. The volume of the tumor xenografted into nude mice was decreased by 51.6% in the celecoxib group (p < 0.01). In conclusion, the increased expression of COX-2 may be responsible for rapid proliferation of pancreatic cancer, and specific inhibition of COX-2 suppresses proliferation of Panc-1 cells in vitro and in nude mice. The selective inhibitor of COX-2 may be an effectual agent for pancreatic cancer chemoprevention.     

Potential involvement of the cyclooxygenase-2 pathway in the regulation of tumor-associated angiogenesis and growth in pancreatic cancer

Angiogenesis plays a crucial role in tumor development and growth. The present investigation was undertaken to test the potential involvement of the cyclooxygenase-2 (COX-2) pathway in the regulation of angiogenesis and growth in pancreatic cancer. We compared the angiogenic characteristics of a COX-2-positive human pancreatic tumor cell line, BxPC-3, with those of a COX-2-negative pancreatic tumor cell line, AsPC-1. Cultured BxPC-3 cells promoted a marked increase of endothelial cell migration in comparison with migration that occurred in the absence of cancer cells. Furthermore, BxPC-3 cell culture supernatants induced endothelial cell capillary morphogenesis in vitro and neovascularization in vivo. In contrast, cultured AsPC-1 cells elicited a modest effect on endothelial cell migration and neovascularization in vivo. Pretreatment of BxPC-3 cells with the selective COX-2 inhibitor NS-398 (50 micro M) dramatically decreased angiogenic responses of endothelial cells. NS-398 (25-100 micro M) caused inhibition of BxPC-3 cell proliferation but had no effect on AsPC-1 cell growth. SC-560, a selective COX-1 inhibitor, had no effect on growth of either cell lines. These results suggest an involvement of COX-2 in the control of tumor-dependent angiogenesis and growth in certain pancreatic cancers and provide the rational for inhibition of the COX pathway as an effective therapeutic approach for pancreatic tumors.     

尼美舒利对结肠癌细胞株PGE2及VEGF表达的影响

目的:探讨选择性环氧化酶2(COX-2)抑制剂对COX-2高表达的结肠癌细胞株HT-29增殖和凋亡的影响,明确以COX-2为靶点治疗结肠癌的作用途径。方法:将选择性COX-2抑制剂尼美舒利(nimesulide)按不同浓度作用于结肠癌细胞系HT-29,用MTT(四甲基偶氮唑蓝比色法)法分别于0、24、48、72h检测细胞增殖状态;流式细胞仪观察尼美舒利对细胞凋亡的影响,进一步采用ELISA法检测药物作用后前列腺素E2(PGE2)的表达,免疫组化法测定内皮细胞生长因子(VEGF)表达阳性率。结果:尼美舒利对结肠癌细胞系HT-29呈时间、剂量依赖性方式抑制细胞增殖,促进其凋亡。PEG2及VEGF表达水平随作用时间延长而下降。结论:选择性COX-2抑制剂可能通过PGE2与VEGF途径影响结肠癌细胞HT-29的增殖与凋亡,是其治疗结肠癌的分子机制。     

In vitro and in vivo inhibitory effect evaluation of cyclooxygenase-2 inhibitors,antisense cyclooxygenase-2 cDNA,and their combination on the growth of human bladder cancer cells

Overexpression of cyclooxygenase (COX)-2 is associated with the progression of various malignancies, but the contribution of COX-2 expression, bioactivity or their cooperation to bladder cancer growth calls for further clarification. In this study, we investigated the inhibitory effect of COX-2 inhibitors, antisense COX-2 nucleotide, and their combination on the growth of bladder cancer cells (5637, 5637-P and 5637-AS). Suppression of either COX-2 expression or activity caused reduced cell proliferation, enhanced cell numbers in G₁ phase, and increased apoptosis; the joint suppression of COX-2 expression and bioactivity enhanced the degree of cell growth inhibition. COX-2 antisense-expressing 5637-AS tumors showed a 41.42 ± 3.08% growth inhibition as compared with 5637 controls. Oral administration of indomethacin (3 mg/kg) or celecoxib (15 mg/kg) caused tumor growth inhibition by 31.5 ± 14.87% or 83.17 ± 1.17%, respectively. When COX-2 antisense cDNA and COX-2 inhibitor celecoxib were combined, the tumor growth inhibition rate was further increased up to 88.78 ± 3.10%. These results provide evidence that celecoxib has potential therapeutic effect on bladder cancer, and the joint use of COX-2 antisense cDNA with celecoxib may improve their individual therapeutic effect, especially significantly increase the growth inhibitory effect of COX-2 antisense cDNA.