Selective COX-2 inhibitor (celecoxib) decreases cellular growth in prostate cancer cell lines independent of p53

Abstract

Celecoxib is a clinically available COX-2 inhibitor that has been reported to have antineoplastic activity. It has been proposed as a preventative agent for several types of early neoplastic lesions. Earlier studies have shown that sensitivity of prostatic carcinoma (PCa) to celecoxib is associated with apoptosis; however, these studies have not demonstrated adequately whether this effect is dependent on p53 status. We studied the relation between sensitivity to celecoxib and the phenotypic p53 status of PCa cells lines, LNCaP (wild type p53), PC3 (null p53) and DU145 (mutated p53). Cellular growth was assessed at 24, 48, 72 and 96 h after celecoxib treatment at concentrations of 0, 10, 30, 50, 70 and 100 μM using an MTT assay. Cellular proliferation (Ki-67 expression) was determined by immunocytochemistry. Phenotypic expression of p53 was analyzed by western blotting. The effects of celecoxib on cellular growth and its association with p53 were assessed after down-regulation of p53 using synthetic interfering RNAs (siRNA) in LNCaP cells. Expression of p53 and COX-2 at mRNA levels was assessed by quantitative real time polymerase reaction (qRT-PCR). We found that celecoxib inhibited cellular growth and proliferation in a dose-dependent manner in all three cell lines; LNCaP cells with a native p53 were the most sensitive to celecoxib. We observed a down- regulation effect on p53 in LNCaP cells exposed to ≥ 30 μM celecoxib for 72 h, but found no significant changes in the p53 levels of DU145 cells, which have a mutated p53. Reduced COX-2 expression was found with decreased p53 in LNCaP and PC-3 cells that were exposed to ≥ 20 μM of celecoxib for 72 h, but COX-2 expression was increased in DU145 cells. All three cell lines demonstrated pan-cytotoxicity when exposed to 100 μM celecoxib. When p53 expression was inhibited using siRNA in LNCaP cells, the inhibitory effects on cellular growth usually exerted by celecoxib were not changed significantly. Celecoxib reduces the growth of prostate cancer cell lines in part by decreasing proliferation, which suggests that the inhibition of growth of LNCaP cells by celecoxib is independent of normal levels of native p53.     

Celecoxib extends C. elegans lifespan via inhibition of insulin-like signaling but not cyclooxygenase-2 activity

One goal of aging research is to develop interventions that combat age-related illnesses and slow aging. Although numerous mutations have been shown to achieve this in various model organisms, only a handful of chemicals have been identified to slow aging. Here, we report that celecoxib, a nonsteroidal anti-inflammatory drug widely used to treat pain and inflammation, extends Caenorhabditis elegans lifespan and delays the age-associated physiological changes, such as motor activity decline. Celecoxib also delays the progression of age-related proteotoxicity as well as tumor growth in C. elegans. Celecoxib was originally developed as a potent cyclooxygenase-2 (COX-2) inhibitor. However, the result from a structural-activity analysis demonstrated that the antiaging effect of celecoxib might be independent of its COX-2 inhibitory activity, as analogs of celecoxib that lack COX-2 inhibitory activity produce a similar effect on lifespan. Furthermore, we found that celecoxib acts directly on 3'-phosphoinositide-dependent kinase-1, a component of the insulin/IGF-1 signaling cascade to increase lifespan.     

Tanshinone IIA suppress the proliferation of HNE-1 nasopharyngeal carcinoma an in vitro study

Nasopharyngeal carcinoma (NPC) at present is considered to be one of the fatal diseases detected commonly in the people belonging to Southeast Asia and southern China. According to the WHO reports among the detected cases of NPC worldwide, 80% are from China. The present study investigates the effect of tanshinone IIA on the migration and invasion potential of HNE-1NPC cells and studied the detailed mechanism involved. Effect of the tanshinone IIA on viability of the HNE-1NPC cells was analyzed by MTS assay. Cell matrigel invasion and wound-healing motility assays, respectively were used for the analysis of invasion and migration potential of HNE-1 cells. Tanshinone IIA inhibited the viability of HNE-1cells in a dose dependent manner. Migration and invasion potential of the tanshinone IIA treated cells was reduced significantly (P < 0.05) compared to the control cells after 48 h. Analysis of the proteins involved in migration and invasion revealed a significant decrease in the expression of matrix metalloproteinase (MMP)-2 and MMP-9 on treatment with tanshinone IIA. It also inhibited the p65 and p50 expression in the nuclear fractions of HNE-1 cells after 48 h. Thus, tanshinone IIA inhibits migration and invasion potential of the HNE-1NPC cells through reduction in the expression of matrix metalloproteinases. Therefore, tanshinone IIA can be used for the treatment of NPC.     

Novel combination of Celecoxib and proteasome inhibitor MG132 provides synergistic antiproliferative and proapoptotic effects in human liver tumor cells

Molecular targeted therapy has shown promise as a treatment for advanced hepatocellular carcinoma (HCC). Celecoxib (Celebrex®) exhibits antitumor effects in human HCC cells, and its mechanism of action is mediated either by its ability to inhibit cyclooxygenase 2 (COX-2) or by a number of various other COX-2 independent effects. Proteasome inhibitors (PIs) can exert cell growth inhibitory and apoptotic effects in different tumor cell types, including HCC cells. The present study examined the interaction between celecoxib and the PI MG132 in two human liver tumor cell lines HepG2 and HA22T/VGH. Our data showed that each inhibitor reduced proliferation and induced apoptosis in a dose-dependent manner in both cell lines. Moreover, the combination of celecoxib with MG132 synergistically inhibited cell viability and increased apoptosis, as documented by caspase 3 and 7 activation, PARP cleavage, and down-regulation of Bcl-2. Celecoxib and MG132, both alone and synergistically in combination, induced expression of the endoplasmic reticulum (ER) stress genes ATF4, CHOP, TRB3 and promoted the splicing of XBP1 mRNA. Knockdown of TRB3 mRNA expression by small interference RNA significantly decreased combination-induced cell death in HA22T/VGH cells, whereas it increased combination-induced cell death in HepG2 cells, suggesting that activation of the ER stress response might have either a detrimental or a protective role in liver tumor cell survival. In conclusion, our data indicate that combination treatment with celecoxib and MG132 resulted in synergistic antiproliferative and proapoptotic effects against liver cancer cells, providing a rational basis for the clinical use of this combination in the treatment of liver cancer.     

Cyclooxygenase (COX)-2 inhibitor celecoxib abrogates TNF-induced NF-kappa B activation through inhibition of activation of I kappa B alpha kinase and Akt in human non-small cell lung carcinoma: correlation with suppression of COX-2 synthesis

The cyclooxygenase 2 (COX-2) inhibitor celecoxib (also called celebrex), approved for the treatment of colon carcinogenesis, rheumatoid arthritis, and other inflammatory diseases, has been shown to induce apoptosis and inhibit angiogenesis. Because NF-kappa B plays a major role in regulation of apoptosis, angiogenesis, carcinogenesis, and inflammation, we postulated that celecoxib modulates NF-kappa B. In the present study, we investigated the effect of this drug on the activation of NF-kappa B by a wide variety of agents. We found that celecoxib suppressed NF-kappa B activation induced by various carcinogens, including TNF, phorbol ester, okadaic acid, LPS, and IL-1 beta. Celecoxib inhibited TNF-induced I kappa B alpha kinase activation, leading to suppression of I kappa B alpha phosphorylation and degradation. Celecoxib suppressed both inducible and constitutive NF-kappa B without cell type specificity. Celecoxib also suppressed p65 phosphorylation and nuclear translocation. Akt activation, which is required for TNF-induced NF-kappa B activation, was also suppressed by this drug. Celecoxib also inhibited the TNF-induced interaction of Akt with I kappa B alpha kinase (IKK). Celecoxib abrogated the NF-kappa B-dependent reporter gene expression activated by TNF, TNF receptor, TNF receptor-associated death domain, TNF receptor-associated factor 2, NF-kappa B-inducing kinase, and IKK, but not that activated by p65. The COX-2 promoter, which is regulated by NF-kappa B, was also inhibited by celecoxib, and this inhibition correlated with suppression of TNF-induced COX-2 expression. Besides NF-kappa B, celecoxib also suppressed TNF-induced JNK, p38 MAPK, and ERK activation. Thus, overall, our results indicate that celecoxib inhibits NF-kappa B activation through inhibition of IKK and Akt activation, leading to down-regulation of synthesis of COX-2 and other genes needed for inflammation, proliferation, and carcinogenesis.     

Cyclooxygenase-2 Inhibition Attenuates Abdominal Aortic Aneurysm Progression in Hyperlipidemic Mice

Abdominal aortic aneurysms (AAAs) are a chronic inflammatory disease that increase the risk of life-threatening aortic rupture. In humans, AAAs have been characterized by increased expression of cyclooxygenase-2 and the inactivation of COX-2 prior to disease initiation reduces AAA incidence in a mouse model of the disease. The current study examined the effectiveness of selective cyclooxygenase-2 (COX-2) inhibition on reducing AAA progression when administered after the initiation of AAA formation. AAAs were induced in hyperlipidemic apolipoprotein E-deficient mice by chronic angiotensin II (AngII) infusion and the effect of treatment with the COX-2 inhibitor celecoxib was examined when initiated at different stages of the disease. Celecoxib treatment that was started 1 week after initiating AngII infusion reduced AAA incidence by 61% and significantly decreased AAA severity. Mice treated with celecoxib also showed significantly reduced aortic rupture and mortality. Treatment with celecoxib that was started at a late stage of AAA development also significantly reduced AAA incidence and severity. Celecoxib treatment significantly increased smooth muscle alpha-actin expression in the abdominal aorta and did not reduce expression of markers of macrophage-dependent inflammation. These findings indicate that COX-2 inhibitor treatment initiated after formation of AngII-induced AAAs effectively reduces progression of the disease in hyperlipidemic mice.     

Down-regulation of glucose-regulated protein (GRP) 78 potentiates cytotoxic effect of celecoxib in human urothelial carcinoma cells

Celecoxib is a selective cyclooxygenase-2 (COX-2) inhibitor that has been reported to elicit anti-proliferative response in various tumors. In this study, we aim to investigate the antitumor effect of celecoxib on urothelial carcinoma (UC) cells and the role endoplasmic reticulum (ER) stress plays in celecoxib-induced cytotoxicity. The cytotoxic effects were measured by MTT assay and flow cytometry. The cell cycle progression and ER stress-associated molecules were examined by Western blot and flow cytometry. Moreover, the cytotoxic effects of celecoxib combined with glucose-regulated protein (GRP) 78 knockdown (siRNA), (-)-epigallocatechin gallate (EGCG) or MG132 were assessed. We demonstrated that celecoxib markedly reduces the cell viability and causes apoptosis in human UC cells through cell cycle G1 arrest. Celecoxib possessed the ability to activate ER stress-related chaperones (IRE-1α and GRP78), caspase-4, and CCAAT/enhancer binding protein homologous protein (CHOP), which were involved in UC cell apoptosis. Down-regulation of GRP78 by siRNA, co-treatment with EGCG (a GRP78 inhibitor) or with MG132 (a proteasome inhibitor) could enhance celecoxib-induced apoptosis. We concluded that celecoxib induces cell cycle G1 arrest, ER stress, and eventually apoptosis in human UC cells. The down-regulation of ER chaperone GRP78 by siRNA, EGCG, or proteosome inhibitor potentiated the cytotoxicity of celecoxib in UC cells. These findings provide a new treatment strategy against UC.     

Celecoxib induces apoptosis by inhibiting the expression of survivin in HeLa cells

The effect of celecoxib, a cyclooxygenase-2 selective inhibitor, on a human cervical cancer cell line, HeLa cells, was examined. We found that celecoxib increased DNA ladder formation and the activity of caspase-3, indicating that celecoxib induced apoptosis in HeLa cells. Celecoxib suppressed the expression of an anti-apoptotic protein, survivin, in both protein and mRNA levels. The overexpression of survivin overrode caspase-3 activation induced by celecoxib. Subsequently, we performed luciferase reporter assay with the reporter vector containing human survivin promoter region and electrophoretic mobility shift assay and found that the -75 to -66 bp region relative to the initiating codon played an important role in celecoxib action to suppress survivin promoter activity. Our findings might provide a new insight into the anti-cancer effects of celecoxib.     

Aspirin, but not NO-releasing aspirin (NCX-4016), interacts with selective COX-2 inhibitors to aggravate gastric damage and inflammation

Aceylation of cyclooxygenase (COX)-2 by aspirin can trigger the formation of 15(R)-epilipoxin A4, or aspirin-triggered lipoxin (ATL). ATL exerts protective effects in the stomach. Selective COX-2 inhibitors block ATL synthesis and exacerbate aspirin-induced gastric damage. Nitric oxide-releasing aspirins, including NCX-4016, have antiplatelet effects similar to aspirin but do not cause gastric damage. In the present study, we examined whether or not NCX-4016 triggers ATL synthesis and/or upregulates gastric COX-2 expression and the effects of coadministration of NCX-4016 with a selective COX-2 inhibitor on gastric mucosal injury and inflammation. Rats were given aspirin or NCX-4016 orally and either vehicle or a selective COX-2 inhibitor (celecoxib) intraperitoneally. Gastric damage was blindly scored, and granulocyte infiltration into gastric tissue was monitored through measurement of myeloperoxidase activity. Gastric PG and ATL synthesis was measured as was COX-2 expression. Whereas celecoxib inhibited gastric ATL synthesis and increased the severity of aspirin-induced gastric damage and inflammation, coadministration of celecoxib and NCX-4016 did not result in damage or inflammation. NCX-4016 did not upregulate gastric COX-2 expression nor did it trigger ATL synthesis (in contrast to aspirin). Daily administration of aspirin for 5 days resulted in significantly less gastric damage than that seen with a single dose, as well as augmented ATL synthesis. Celecoxib reversed this effect. In contrast, repeated administration of NCX-4016 failed to cause gastric damage, whether given alone or with celecoxib. These studies support the notion that NCX-4016 may be an attractive alternative to aspirin for indications such as cardioprotection, including in individuals also taking selective COX-2 inhibitors.     

Role of leukotriene B4 in celecoxib-mediated anticancer effect

Celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, has anticancer effect on many cancers associated with chronic inflammation by both COX-2-dependent and COX-2-independent mechanisms. The non-COX-2 targets of celecoxib, however, are still a matter of research. Leukotriene B₄ (LTB₄) has been implicated in prostate and colon carcinogenesis, but little is known about the potential role of LTB₄ in celecoxib-mediated anticancer effect. In this study, we evaluated whether LTB₄ was involved in celecoxib-mediated inhibitory effect on human colon cancer HT-29 cells and human prostate cancer PC-3 cells. Our data showed that survival of both cell lines was obviously suppressed after celecoxib treatment for 72 h in a concentration-dependent manner. However, only in HT-29 cells, this inhibitory effect could be reversed by LTB₄, which promoted survival of HT-29 cells rather than PC-3 cells. Consistent with these results, lioxygenase (LOX) potent inhibitor nordihydroguaiaretic acid (NDGA) had a higher inhibitory effect on HT-29 cells than PC-3 cells. Additionally, ELISA results showed that celecoxib could suppress expression of LTB₄ in both cell lines, whereas, inhibition of PGE₂ was only detected in HT-29 cells. These results indicate that the anticancer effect of celecoxib is COX-2-independent in HT-29 and PC-3 cells and in HT-29 cells primarily via down-regulating LTB₄ production.     

A Trifluoromethyl Analogue of Celecoxib Exerts Beneficial Effects in Neuroinflammation

Celecoxib is a selective cyclooxygenase-2 (COX2) inhibitor. We have previously shown that celecoxib inhibits experimental autoimmune encephalomyelitis (EAE) in COX-2-deficient mice, suggestive for a mode of action involving COX2-independent pathways. In the present study, we tested the effect of a trifluoromethyl analogue of celecoxib (TFM-C) with 205-fold lower COX-2 inhibitory activity in two models of neuroinflammation, i.e. cerebellar organotypic cultures challenged with LPS and the EAE mouse model for multiple sclerosis. TFM-C inhibited secretion of IL-1β, IL-12 and IL-17, enhanced that of TNF-α and RANTES, reduced neuronal axonal damage and protected from oxidative stress in the organotypic model. TFM-C blocked TNF-α release in microglial cells through a process involving intracellular retention, but induced TNF-α secretion in primary astrocyte cultures. Finally, we demonstrate that TFM-C and celecoxib ameliorated EAE with equal potency. This coincided with reduced secretion of IL-17 and IFN-γ by MOG-reactive T-cells and of IL-23 and inflammatory cytokines by bone marrow-derived dendritic cells. Our study reveals that non-coxib analogues of celecoxib may have translational value in the treatment of neuro-inflammatory conditions.     

Selective cyclooxygenase-2 inhibitors show a differential ability to inhibit proliferation and induce apoptosis of colon adenocarcinoma cells

Although the influence of selective cyclooxygenase (COX)-2 inhibitors on the proliferation of colon adenocarcinoma cells have been the subject of much investigation, relatively little research has compared the effects of different COX-2 inhibitors. Celecoxib strongly suppressed the proliferation of COX-2 expressing HT-29 cells at 10-40 microM. NS-398 and nimesulide also inhibited cell proliferation, whereas rofecoxib, meloxicam, and etodolac did not. Only celecoxib induced apoptosis of HT-29 cells, as detected on the basis of DNA fragmentation, TUNEL positivity, and caspase-3/7 activation. DNA fragmentation was also increasd in COX-2 non-expressing cell lines (SW-480 and HCT-116) by exposure to celecoxib for 6-24 h. All six COX-2 inhibitors suppressed the production of prostaglandin E(2) by HT-29 cells, suggesting that the pro-apoptotic effect of celecoxib was unrelated to inhibition of COX-2. Inactivation of Akt might explain the differential pro-apoptotic effect of these selective COX-2 inhibitors on colon adenocarcinoma cells.     

Celecoxib increases retinoid sensitivity in human colon cancer cell lines

Retinoid resistance has limited the clinical application of retinoids as differentiation-inducing and apoptosis-inducing drugs. This study was designed to investigate whether celecoxib, a selective COX-2 inhibitor, has effects on retinoid sensitivity in human colon cancer cell lines, and to determine the possible mechanism of said effects. Cell viability was measured using the MTT assay. Apoptosis was detected via Annexin-V/PI staining and the flow cytometry assay. PGE₂ production was measured with the ELISA assay. The expression of RARβ was assayed via western blotting. The results showed that celecoxib enhanced the inhibitory effect of ATRA in both COX-2 high-expressing HT-29 and COX-2 low-expressing SW480 cell lines. Further study showed the ATRA and celecoxib combination induced greater apoptosis, but that the addition of PGE₂ did not affect the enhanced growth-inhibitory and apoptosis-inducing effects of the combination. Moreover, NS398 (another selective COX-2 inhibitor) did not affect the inhibitory effects of ATRA in the two cell lines. Western blotting showed that the expression of RARβ in HT-29 cell lines was increased by celecoxib, but not by NS398, and that the addition of PGE₂ did not affect the celecoxib-induced expression of the retinoic acid receptor beta. In conclusion, celecoxib increased the expression of RARβ and the level of cellular ATRA sensitivity through COX-2-independent mechanisms. This finding may provide a potential strategy for combination therapy.     

Celecoxib, a cyclooxygenase-2 inhibitor, induces apoptosis in human osteosarcoma cell line MG-63 via down-regulation of PI3K/Akt

Cyclooxygenase-2 (COX-2), involved in the inhibition of apoptosis and, the potentiation of cell growth, is frequently overexpressed in human malignancies including osteosarcoma (OS). We have attempted to identify the anti-proliferation of celecoxib, a selective COX-2 inhibitor, and the combination of celecoxib and cisplatin in MG-63 cells, and to explore the potential molecular mechanisms involved. MG-63 cells were treated with the combination of celecoxib and cisplatin or either agent alone for 48h in serum-supplemented medium. Celecoxib caused G1 phase arrest and significantly inhibited cell growth, as well as potentiating cisplatin-induced apoptosis. The effect was dose-dependent, and apoptotic changes such as DNA fragments and apoptotic bodies were observed. However, downregulation of COX-2 did not occur in cells treated with celecoxib. Phosphoinositide-3-kinase (PI3K)/Akt, survivin, bcl-2 were significantly downregulated in cells treated with the combination of celecoxib and cisplatin, and decreased survivin and bcl-2 levels were found in cells with wortmannin, a specific PI3K inhibitor. Moreover, the decreased expressions of procaspase-9, procaspase-3 and cleaved PARP-1 were detected by Western blot analysis. Therefore, celecoxib exerts its anti-tumor activities through COX-2-independent mechanisms, which may be PI3K/Akt-dependent, and survivin and bcl-2-related. PI3K may be at the center of the celecoxib effects, which play an essential role in the regulation of survivin and Bcl-2.     

塞来昔布对直肠癌HCA-7 细胞放射敏感性的实验研究

目的:观察环氧合酶-2(COX-2)抑制剂塞来昔布对直肠癌HCA-7细胞株的放射敏感性及探讨其机制。方法:采用MTT法检测塞来昔布作用不同时间对直肠癌HCA-7细胞株增殖的影响,计算出塞来昔布的半数抑制浓度IC50;HCA-7细胞克隆形成实验用于检测塞来昔布对HCA-7细胞的放射敏感性,并绘制存活曲线;流式细胞仪(FCM)测定塞来昔布对HCA-7的细胞周期的影响。结果:塞来昔布对HCA-7细胞株的抑制率随时间的延长而升高,48h的IC50是40.19μmol/L;照射组+药物组的SF2、D0、Dq、SER较单纯照射组均有所下降。塞来昔布使HCA-7细胞发生G2和M期阻滞,并抑制S期的比例。结论:塞来昔布能增加直肠癌HCA-7细胞的放射敏感性。     

The cyclooxygenase-2 inhibitor celecoxib induces apoptosis by blocking Akt activation in human prostate cancer cells independently of Bcl-2

This study investigates the apoptotic activity of the cyclooxygenase-2 (COX-2) inhibitor celecoxib in prostate carcinoma cells. COX-2 is constitutively expressed in androgen-responsive LNCaP and androgen-nonresponsive PC-3 cells. Exposure of these cells to celecoxib induces characteristic features of apoptosis, including morphological changes, DNA laddering, and caspase-3 activation, whereas piroxicam, a COX-1-specific inhibitor, displays no appreciable effect on either cancer cell line even after prolonged exposure. Moreover, the potency of celecoxib in apoptosis induction is significantly higher than that of other COX-2 inhibitors examined despite the observation that these inhibitors exhibit similar IC(50) in COX-2 inhibition. It is noteworthy that normal human prostate epithelial cells, expressing a marginally detectable level of COX-2, are insensitive to the induction of apoptosis by celecoxib. These data suggest a correlation between COX-2 expression and sensitivity to the apoptotic effect of the COX-2 inhibitor. In an effort to delineate the underlying mechanism, we examined the effect of celecoxib on the expression of Bcl-2 as well as the activation of the key anti-apoptotic kinase Akt. In contrast to an earlier report that attributed the apoptotic activity of NS398 in LNCaP cells to Bcl-2 down-regulation, we provide evidence that the induction of apoptosis by celecoxib in LNCaP and PC-3 cells is independent of Bcl-2. First, treatment with celecoxib does not alter the cellular Bcl-2 level in both cell lines. Second, enforced Bcl-2 expression in PC-3 cells does not confer protection against the induction of apoptosis by celecoxib. Our data show that celecoxib treatment blocks the phosphorylation of Akt. This correlation is supported by studies showing that overexpression of constitutively active Akt protects PC-3 cells from celecoxib-induced apoptosis. Nevertheless, how celecoxib down-regulates Akt is not clear because the drug does not adversely affect phosphoinositide 3-kinase activity in vivo and okadaic acid, a protein phosphatase 2A inhibitor, cannot rescue the inhibition. In summary, our data demonstrate that inhibition of Akt activation may play a crucial role in the induction of apoptosis by celecoxib.     

Celecoxib Ameliorates Portal Hypertension of the Cirrhotic Rats through the Dual Inhibitory Effects on the Intrahepatic Fibrosis and Angiogenesis

Background

Increased intra-hepatic resistance to portal blood flow is the primary factor leading to portal hypertension in cirrhosis. Up-regulated expression of cyclooxygenase-2 (COX-2) in the cirrhotic liver might be a potential target to ameliorate portal hypertension.

Objective

To verify the effect of celecoxib, a selective inhibitor of COX-2, on portal hypertension and the mechanisms behind it.

Methods

Cirrhotic liver model of rat was established by peritoneal injection of thiacetamide (TAA). 36 rats were randomly assigned to control, TAA and TAA+celecoxib groups. Portal pressures were measured by introduction of catheters into portal vein. Hepatic fibrosis was assessed by the visible hepatic fibrotic areas and mRNAs for collagen III and α-SMA. The neovasculature was determined by hepatic vascular areas, vascular casts and CD31 expression. Expressions of COX-2, vascular endothelial growth factor (VEGF), VEGF receptor-2 (VEGFR-2) and related signal molecules were quantitated.

Results

Compared with TAA group, the portal pressure in TAA+celecoxib group was significantly decreased by 17.8%, p<0.01. Celecoxib treatment greatly reduced the tortuous hepatic portal venules. The data of fibrotic areas, CD31expression, mRNA levels of α-SMA and collagen III in TAA+celecoxib group were much lower than those in TAA group, p<0.01. Furthermore, the up-regulation of hepatic mRNA and protein levels of VEGF, VEGFR-2 and COX-2 induced by TAA was significantly inhibited after celecoxib treatment. The expressions of prostaglandin E2 (PGE2), phosphorylated extracellular signal-regulated kinase (p-ERK), hypoxia-inducible factor-1α (HIF-1α), and c-fos were also down-regulated after celecoxib treatment.

Conclusions

Long term administration of celecoxib can efficiently ameliorate portal hypertension in TAA rat model by its dual inhibitory effects on the intrahepatic fibrosis and angiogenesis. The anti-angiogenesis effect afforded by celecoxib may attribute to its modulation on VEGF/VEGFR-2 through the down-regulation of integrated signal pathways involving PGE2- HIF-1α- VEGF and p-ERK- c-fos- VEGFR-2.     

Effusanin E Suppresses Nasopharyngeal Carcinoma Cell Growth by Inhibiting NF-κB and COX-2 Signaling

Rabdosia serra is well known for its antibacterial, anti-inflammatory and antitumor activities, but no information has been available for the active compounds derived from this plant in inhibiting human nasopharyngeal carcinoma (NPC) cell growth. In this study, we isolated and purified a natural diterpenoid from Rabdosia serra and identified its chemical structure as effusanin E and elucidated its underlying mechanism of action in inhibiting NPC cell growth. Effusanin E significantly inhibited cell proliferation and induced apoptosis in NPC cells. Effusanin E also induced the cleavage of PARP, caspase-3 and -9 proteins and inhibited the nuclear translocation of p65 NF-κB proteins. Moreover, effusanin E abrogated the binding of NF-κB to the COX-2 promoter, thereby inhibiting the expression and promoter activity of COX-2. Pretreatment with a COX-2 or NF-κB-selective inhibitor (celecoxib or ammonium pyrrolidinedithiocarbamate) had an additive effect on the effusanin E-mediated inhibition of proliferation, while pretreatment with an activator of NF-κB/COX-2 (lipopolysaccharides) abrogated the effusanin E-mediated inhibition of proliferation. Effusanin E also significantly suppressed tumor growth in a xenograft mouse model without obvious toxicity, furthermore, the expression of p50 NF-κB and COX-2 were down-regulated in the tumors of nude mice. These data suggest that effusanin E suppresses p50/p65 proteins to down-regulate COX-2 expression, thereby inhibiting NPC cell growth. Our findings provide new insights into exploring effusanin E as a potential therapeutic compound for the treatment of human nasopharyngeal carcinoma.     

An exploratory trial of cyclooxygenase type 2 inhibitor in HIV-1 infection: downregulated immune activation and improved T cell-dependent vaccine responses

Chronic HIV infection is characterized by chronic immune activation and dysfunctional T cells with elevated intracellular cyclic AMP (cAMP), which inhibits the T cell activation capability. cAMP may be induced by prostaglandin E(2) following lipopolysaccharide (LPS)-induced upregulation of cyclooxygenase type 2 (COX-2) in monocytes due to the elevated LPS levels in patients with chronic HIV infection. This hypothesis was tested using celecoxib, a COX-2 inhibitor, for 12 weeks in HIV-infected patients without antiretroviral treatment in a prospective, open, randomized exploratory trial. Thirty-one patients were randomized in the trial; 27 completed the study, including 13 patients on celecoxib. Celecoxib reduced chronic immune activation in terms of CD38 density on CD8(+) T cells (-24%; P = 0.04), IgA levels (P = 0.04), and a combined score for inflammatory markers (P < 0.05). Celecoxib further reduced the inhibitory surface receptor programmed death 1 (PD-1) on CD8(+) T cells (P = 0.01), including PD-1 on the HIV Gag-specific subset (P = 0.02), enhanced the number of CD3(+) CD4(+) CD25(+) CD127(lo/-) Treg or activated cells (P = 0.02), and improved humoral memory recall responses to a T cell-dependent vaccine (P = 0.04). HIV RNA (P = 0.06) and D dimers (P = 0.07) tended to increase in the controls, whereas interleukin-6 (IL-6) possibly decreased in the treatment arm (P = 0.10). In conclusion, celecoxib downmodulated the immune activation related to clinical progression of chronic HIV infection and improved T cell-dependent functions in vivo.