The effects of the β-lactam antibiotic,ceftriaxone, on forepaw stepping and l-DOPA-induced dyskinesia in a rodent model of Parkinson’s disease

Rationale

Glutamate receptor antagonists can improve the symptoms of Parkinson’s disease (PD) and reduce l-3,4-dihydroxyphenylalanine (l-DOPA)-induced dyskinesia (LID) in both animal models and humans, but usually produce intolerable side effects. Recent evidence suggests that upregulation of the major glutamate transporter, GLT-1, by the β-lactam antibiotic, ceftriaxone, can increase the removal of synaptic glutamate without producing noticeable side effects, and may provide an effective alternative to receptor antagonists for several neurodegenerative diseases.

Objectives

We examined whether repeated i.p. injections of ceftriaxone would, like glutamate antagonists, reduce the deficits in contralateral forepaw stepping produced by unilateral injections of 6-OHDA into the medial forebrain bundle of rats and reduce LID (as measured by abnormal involuntary movements).

Methods and results

In Experiment 1, daily injections of 100 mg/kg ceftriaxone improved contralateral forepaw stepping by 44 %, and these therapeutic effects were still apparent 29 days following the cessation of treatment. In Experiment 2, daily injections of 50 mg/kg ceftriaxone were as effective as daily injections of 10 mg/kg?l-DOPA in increasing contralateral forepaw stepping by 40 %. These therapeutic effects of ceftriaxone were decreased by an injection of 10 mg/kg of the selective GLT-1 antagonist, dihydrokainate (DHK), and were still evident 69 days after the cessation of ceftriaxone injections. Furthermore, ceftriaxone did not produce dyskinesia by itself and reduced the development, but not the expression, of LID.

Conclusions

These data suggest that ceftriaxone, by producing a long-term increase in GLT-1 function and increasing the removal of synaptic glutamate, may offer several advantages over l-DOPA as therapy for PD.     

Comparison of the determination of β-lactam antibiotic drugs in plasma of rabbits by means of HPLC and of a microbiological assay

The present study compares the determination of the plasma concentrations of ampicillin, amoxycillin and cefuroxime in rabbits, by means of high performance liquid chromatography and the microbiological assay. The correlation coefficient between the data obtained by these methods are for ampicillin 0.991, amoxycillin 0.994 and cefuroxime 0.991. Plasma constituents interfering with amoxycillin in theHplc determinations, were not encountered in the plasma of man.     

Characterisation of the β-lactam resistance enzyme in Acanthamoeba castellanii

β-Lactams are well known as the best antibiotics for inhibiting the cross-linking between adjacent polysaccharide chains and peptides in the peptidoglycan layer of bacterial cell walls, causing bacterial cell lysis. There are no reports on the action of and resistance mechanisms to β-lactams in protozoa. Acanthamoeba castellanii is a free-living protozoan pathogen capable of causing blinding keratitis and fatal granulomatous encephalitis. When Acanthamoeba is exposed to harsh conditions, it differentiates into the cyst stage to avoid environmental stresses, such as drug treatment. In this study, it was shown that the mature encystation rate of A. castellanii is decreased by treatment with cefotaxime (CTX) and clavulanic acid (CLA); however, the drugs do not kill the amoeba. We hypothesise that β-lactam antibiotics may disturb synthesis of the double cell wall during the encystation process of Acanthamoeba. Interestingly, CTX is considered a powerful β-lactam, whereas CLA is considered a weak β-lactam but an efficient β-lactamase inhibitor. It was demonstrated that Acanthamoeba expresses β-lactamases to prevent inhibition of the encystation process by β-lactams. To reveal the functions of Acanthamoeba β-lactamases, a recombinant Acanthamoeba β-lactamase was produced in Escherichia coli that conferred resistance to β-lactams such as CTX, cefuroxime, penicillin and meropenem. Consequently, we suggest that Acanthamoeba produces enzymes similar to β-lactamases to avoid interference from the environment. Here we provide a new point of view on an important gene responsible for drug resistance and advocate for the development of more efficient treatment against Acanthamoeba infection.     

Antagonism of the morphine-induced Straub tail reaction by κ-opioid receptor activation in mice

The Straub tail reaction (STR) induced by intracerebroventricular injection (ICV) of morphine was significantly antagonized by -funaltrexamine (-FNA, antagonist), given intracerebroventricularly (ICV), but not naltrindole given ICV (NTI, antagonist) or SC norbinaltorphimine given subcutaneously (SC) (nor-BNI, antagonist). When given either SC or ICV the -agonist, U-50,488H markedly suppressed the STR elicited by ICV morphine; these effects were reversed by nor-BNI. These results suggest that the activation of supraspinal receptors can inhibit the ICV morphine-induced STR which results from activation of supraspinal receptors.     

Role of α1- and β3-adrenoceptors in the modulation by SR59230A of the effects of MDMA on body temperature in the mouse

Background and purpose:

We have investigated the ability of the β₃-adrenoceptor antagonist 1-(2-ethylphenoxy)-3-[[(1S)-1,2,3,4,-tetrahydro-1-naphthalenyl]amino]-(2S)-2-propanol hydrochloride (SR59230A) to affect the hyperthermia produced by methylenedioxymethamphetamine (MDMA) in conscious mice and whether α₁-adrenoceptor antagonist actions are involved.

Experimental approach:

Mice were implanted with temperature probes under anaesthesia, and allowed 2 week recovery. MDMA (20 mg·kg⁻¹) was administered subcutaneously 30 min after vehicle or test antagonist and effects on body temperature monitored by telemetry.

Key results:

Following vehicle, MDMA produced a slowly developing hyperthermia, reaching a maximum increase of 1.8°C at 130 min post injection. A low concentration of SR59230A (0.5 mg·kg⁻¹) produced a small but significant attenuation of the slowly developing hyperthermia to MDMA. A high concentration of SR59230A (5 mg·kg⁻¹) revealed a significant and marked early hypothermic reaction to MDMA, an effect that was mimicked by the α₁-adrenoceptor antagonist prazosin. Functional and ligand binding studies revealed actions of SR59230A at α₁-adrenoceptors.

Conclusions and implications:

1-(2-ethylphenoxy)-3-[[(1S)-1,2,3,4,-tetrahydro-1-naphthalenyl]amino]-(2S)-2-propanol hydrochloride in high concentrations modulates the hyperthermic actions of MDMA in mice in two ways: by blocking an early α₁-adrenoceptor-mediated component to reveal a hypothermia, and by a small attenuation of the later hyperthermic component which may possibly be β₃-adrenoceptor-mediated (this seen with the low concentration of SR59230A). Hence, the major actions of SR59230A in modulating the actions of MDMA on temperature involve α₁-adrenoceptor antagonism.     

Industrial landmarks in the development of sustainable production processes for the β-lactam antibiotic key intermediate 7-aminocephalosporanic acid (7-ACA)

Reflecting its importance as key intermediate for the large scale manufacture of β-lactam-type antibiotic drugs being widely used in antibacterial therapy, tremendous achievements have been made over the past decades in developing both, economically and ecologically attractive production routes for 7-aminocephalosporanic acid (7-ACA). Representative achievements and industrial landmarks thereof are described in this review. With cephalosporin C a starting material being accessible through fermentation is readily available in bulk quantities. Initially a chemical production process in organic medium based on various reagents for protection group chemistry and acyclic amide activation served as the large scale production technology for transforming cephalosporin C into 7-ACA. Subsequently, a bi-enzymatic production in aqueous reaction medium based on the use of a D-amino acid oxidase for side chain modification and glutaryl acylase for side chain cleavage was developed. This biocatalytic approach also turned out as an industrial scale solution and dramatically reduced the amount of waste from 31 kg (for the "original chemical process") to less than 1 kg. The latest innovation has been the extension of the two-step bi-enzymatic process towards a one-step monoenzymatic process based on a direct cleavage of the acyclic amide bond of cephalosporin C by means of a cephalosporin C acylase. This alternative, economically efficient and sustainable biotechnological process has already been established on industrial scale in recent years. These biotechnological achievements represent industrial landmarks in biocatalysis and examples that modern biocatalysis can contribute to the development and implementation of highly economical as well as sustainable industrial manufacturing processes.     

Differences in the characteristics of tolerance to μ-opioid receptor agonists in the colon from wild type and β-arrestin2 knockout mice

Drawbacks to opioid use include development of analgesic tolerance and persistent constipation. We previously reported that tolerance to morphine develops upon repeated exposure in the isolated ileum but not the isolated colon. The cellular mechanisms of antinociceptive tolerance vary among μ-opioid receptor agonists. In this study, we assess β-arrestin2 deletion on the development of tolerance to different opioids in ileum and colon circular muscle. Tolerance was determined by assessing the ability of repeated in-vitro opioid exposure to induce contraction of the circular muscle from C57BL/6 wild type (WT) and β-arrestin2 knockout (KO) mice. Repeated exposure every 30 min with in-between washes resulted in tolerance to all agonists in the ileum of both WT and KO mice. However, in the colon of WT mice, comparison of the contractions between the 4th exposure and 1st response was similar to DAMGO (100 ± 10%; N=5) but reduced to fentanyl (62 ± 13%; N=8) and etorphine (38 ± 4%; N=7) indicative of tolerance to fentanyl and etorphine but not DAMGO. In contrast, all agonists produced tolerance in the colon of KO: DAMGO response at the 4th exposure decreased to 52 ± 10% (N=5), fentanyl to 20 ± 5% (N=6) and etorphine 33 ± 7% (N=6). Differences in tolerance among opioid agonists in the colon suggest ligand bias. The deletion of β-arrestin2 in colon appears to be necessary for tolerance to DAMGO but not fentanyl or etorphine. β-arrestin2 potentially represents an important target for treating opioid-induced bowel dysfunction and warrants further exploration of its ligand bias.     

Amphetamine-induced activation of forebrain EEG is prevented by noradrenergic β-receptor blockade in the halothane-anesthetized rat

Rationale: Amphetamine (AMPH)-like stimulants represent an intensively studied class of psychoactive drugs. Despite the well-known and potent arousal-enhancing effects of these drugs, the neurobiological substrates of AMPH-induced arousal have rarely been examined explicitly. Activity of the locus coeruleus-noradrenergic system is causally and positively related to behavioral and electroencephalographic (EEG) indices of arousal. For example, activation of locus coeruleus neurons or stimulation of medial basal forebrain noradrenergic β-receptors elicits activation of forebrain EEG in the anesthetized rat. Further, stimulation of noradrenergic β-receptors within the medial basal forebrain elicits a substantial increase in alert, active waking. These and other observations suggest that at least some of the arousal-enhancing actions of AMPH-like stimulants derive from AMPH-induced increases in noradrenergic neurotransmission at β-receptors. The current study examines the extent to which AMPH-induced activation of cortical EEG is dependent on actions of central β-receptors. Methods: The effects of intracerebroventricular (ICV; 2 μl) pretreatment with either vehicle (artificial extracellular fluid) or the β-antagonist, timolol (25, 50 or 100 μg), on the cortical EEG activating effects of intravenous AMPH (0.15 mg/kg) were examined in the halothane-anesthetized rat. EEG was recorded on polygraph and video recording tape and later analyzed using power spectral analyses (PSA). AMPH-induced alteration in cortical EEG activity was measured using PSA in vehicle- and timolol-pretreated animals. Results: Neither vehicle nor timolol ICV infusions altered cortical EEG activity patterns. In vehicle-pretreated animals, AMPH elicited a robust activation of cortical EEG, characterized by the substantial decrease in large-amplitude, slow-wave activity. Timolol pretreatment dose-dependently prevented AMPH-induced cortical EEG activation. This effect of timolol was statistically significant at the 50 μg and 100 μg dose. Conclusions: These observations indicate that, under these experimental conditions, AMPH-induced activation of the forebrain is dependent on actions of noradrenergic β-receptors. Combined with previous observations, these observations support the hypothesis that AMPH-induced increases in arousal involve noradrenergic neurotransmission at β-receptors. Received: 23 June 1999 / Final version: 15 September 1999     

Abecarnil, a β-carboline derivative, does not exhibit anticonvulsant tolerance or withdrawal effects in mice

Development of tolerance and dependence has been reported to occur upon chronic administration of traditional benzodiazepines (BZDs). We compared the effect of chronic treatment with abecarnil, a -carboline derivative with high affinity for central BDZ receptors, and diazepam, the BDZ prototype, in mice.After acute administration, abecarnil was as potent and effective as diazepam in protecting from bicuculline-induced convulsion. The time-course analysis of two peak equieffective doses of abecarnil (1.9 mg/kg p.o.) and diazepam (2.7 mg/kg p.o.) showed a similar duration of action. The anticonvulsant potency of diazepam was reduced in mice given chronic diazepam (25 mg/kg p.o., 2 times a day for 17 days). No tolerance to abecarnil was apparent when the drug was administered for the same period using a comparable dose (20 mg/kg p.o.). Severe symptoms of precipitated withdrawal were observed upon administration of the BDZ partial inverse agonist Ro 15-3505 in mice treated chronically with diazepam but not abecarnil. In mice made tolerant to diazepam, maximum [³H]-flumazenil binding sites were reduced in both cerebral cortex (–50%) and cerebellum (–55.2%). No changes in [³H]-flumazenil binding were measured in chronic abecarnil-treated mice.These data indicate that abecarnil possesses a very low tolerance/dependence liability and does not affect BZD receptor density after chronic administration.     

The role of the ATP-binding cassette transporter P-glycoprotein in the transport of β-amyloid across the blood-brain barrier

The blood-brain barrier (BBB) protects the brain against endogenous and exogenous compounds and plays an important part in the maintenance of the microenvironment of the brain. In particular, the importance of brain-to-blood transport of brain-derived metabolites across the BBB has gained increasing attention as a potential mechanism in the pathogenesis of neurodegenerative disorders such as Alzheimer's disease, which is characterized by the aberrant polymerization and accumulation of specific misfolded proteins, particularly β-amyloid (Aβ). There is growing evidence that the ABC transport protein P-glycoprotein (P-gp), a major component of the BBB, mediates the efflux of Aβ from the brain. In this review, we discuss the possible role of P-gp in Alzheimer's disease and other neurodegenerative disorders, and consider how a fuller understanding of this function might promote the development of more effective treatment strategies.     

Recent progress in understanding of structure, ligand interactions and the mechanism of activation of the β₂-adrenergic receptor

The understanding of β?-adrenergic receptor (β?AR) interactions with ligands as well as the mechanism of receptor activation changed radically from 2007, when the first crystallographic structure of the receptor was reported. Since then numerous crystallographic studies described interactions with all main classes of β?AR ligands and with G proteins, which provided a great insight into the molecular structure of the receptor. However, molecular mechanisms of receptor activations remain to be determined. Functional research supported the concept of ligand-directed signaling at β-adrenoceptors. Agonist can activate alternative signaling pathways with different capacities and trigger cellular effects. It indicates that agonists nominally belonging to the same class may bind to and/or stabilize different active conformations of the receptor which are selectively recognized by signaling proteins in the allosteric manner.     

Role of channel activation in cognitive enhancement mediated by α7 nicotinic acetylcholine receptors

Background and purpose:

Several agonists of the α7 nicotinic acetylcholine receptor (nAChR) have been developed for treatment of cognitive deficits. However, agonist efficacy in vivo is difficult to reconcile with rapid α7 nAChR desensitization in vitro; and furthermore, the correlation between in vitro receptor efficacy and in vivo behavioural efficacy is not well delineated. The possibility that agonists of this receptor actually function in vivo as inhibitors via desensitization has not been finally resolved.

Experimental approach:

Two structurally related α7 nAChR agonists were characterized and used to assess the degree of efficacy required in a behavioural paradigm.

Key results:

NS6784 activated human and rat α7 nAChR with EC₅₀s of 0.72 and 0.88 µM, and apparent efficacies of 77 and 97% respectively. NS6740, in contrast, displayed little efficacy at α7 nAChR (<2% in oocytes, ≤8% in GH4C1 cells), although its agonist-like properties were revealed by adding a positive allosteric modulator of α7 nAChRs or using the slowly desensitizing α7V274T receptor. In mouse inhibitory avoidance (IA) memory retention, NS6784 enhanced performance as did the 60% partial agonist A-582941. In contrast, NS6740 did not enhance performance, but blocked effects of A-582941.

Conclusions and implications:

Collectively, these findings suggest that a degree of α7 nAChR agonist efficacy is required for behavioural effects in the IA paradigm, and that such behavioural efficacy is not due to α7 nAChR desensitization. Also, a partial agonist of very low efficacy for this receptor could be used as an inhibitor, in the absence of α7 nAChR antagonists with favourable CNS penetration.     

Pioglitazone ameliorates memory deficits in streptozotocin-induced diabetic mice by reducing brain β-amyloid through PPARγ activation

Aim:

To examine the effects of pioglitazone, a PPARγ agonist, on memory performance and brain amyloidogenesis in streptozotocin (STZ)-induced diabetic mice.

Methods:

ICR male mice were injected with STZ (150 mg/kg, iv) to induce experimental diabetes. Pioglitazone (9 and 18 mg·kg^-1·d^-1, po) was administered for 6 weeks. Passive avoidance and Morris water maze (MWM) tests were used to evaluate cognitive function. The blood glucose and serum insulin levels were detected using the glucose oxidase method and an ELISA assay, respectively. β-amyloid (Aβ), β-amyloid precursor protein (APP), β-amyloid precursor protein cleaving enzyme 1 (BACE1), NF-κB p65, the receptor for advanced glycation end products (RAGE) and PPARγ in the brains were analyzed using Western blotting assays.

Results:

The STZ-induced diabetic mice characterized by hyperglycemia and hypoinsulinemia performed poorly in both the passive avoidance and MWM tests, accompanied by increased Aβ_1–40/Aβ_1–42, APP, BACE1, NF-κB p65 and RAGE levels and decreased PPARγ level in the hippocampus and cortex. Chronic pioglitazone treatment significantly ameliorated the memory deficits and amyloidogenesis of STZ-induced diabetic mice, and suppressed expression of APP, BACE1, RAGE and NF-κB p65, and activated PPARγ in the hippocampus and cortex. However, pioglitazone did not significantly affect blood glucose and insulin levels.

Conclusion:

Pioglitazone ameliorates memory deficits in STZ-induced diabetic mice by reducing brain Aβ level via activation of PPARγ, which is independent of its effects on blood glucose and insulin levels. The results suggest that pioglitazone may be used for treating the cognitive dysfunction in type 1 diabetes mellitus.     

Angiotensin II generation in the rat vena cava: Stimulation of local synthesis by β-adrenoceptor activation

Summary There is considerable evidence to suggest that isolated tissues have the capacity to generate angiotensin II and that angiotensin 11 thus generated may enhance noradrenergic neurotransmission. In the present study the possibility that there may be local formation of angiotensin II within the rat vena cava and its consequence to noradrenergic transmission has been investigated. The angiotensin II precursors, angiotensin I and a synthetic tetradecapeptide renin substrate, each enhanced the stimulation-induced efflux of radioactivity from tissues previously incubated with ³H-noradrenaline. The effects of angiotensin I were blocked by the converting enzyme inhibitor captopril and the receptor antagonist saralasin, indicating local conversion to angiotensin II. The effect of the tetradecapeptide was blocked by saralasin, but not by captopril, suggesting either a direct effect of this peptide or conversion to angiotensin II by a pathway not involving angiotensin converting enzyme. The -adrenoceptor agonist isoprenaline enhanced noradrenergic transmission in the rat vena cava, relaxed guinea-pig trachea precontracted with carbachol and increased heart rate in rat isolated atria. Captopril and saralasin blocked the effect of isoprenaline in the vena cava, but did not alter its effects in the atria or trachea. This suggests that in the rat vena cava the facilitation of noradrenergic transmission by isoprenaline may involve stimulation of local angiotensin II production. Send offprint requests to D. F. Story at the above address     

Role for engagement of β‐arrestin2 by the transactivated EGFR in agonist‐specific regulation of δ receptor activation of ERK1/2

Background and Purpose

β‐Arrestins function as signal transducers linking GPCRs to ERK1/2 signalling either by scaffolding members of ERK1/2s cascades or by transactivating receptor tyrosine kinases through Src‐mediated release of transactivating factor. Recruitment of β‐arrestins to the activated GPCRs is required for ERK1/2 activation. Our previous studies showed that δ receptors activate ERK1/2 through a β‐arrestin‐dependent mechanism without inducing β‐arrestin binding to the δ receptors. However, the precise mechanisms involved remain to be established.

Experimental Approach

ERK1/2 activation by δ receptor ligands was assessed using HEK293 cells in vitro and male Sprague Dawley rats in vivo. Immunoprecipitation, immunoblotting, siRNA transfection, intracerebroventricular injection and immunohistochemistry were used to elucidate the underlying mechanism.

Key Results

We identified a new signalling pathway in which recruitment of β‐arrestin2 to the EGFR rather than δ receptor was required for its role in δ receptor‐mediated ERK1/2 activation in response to H‐Tyr–Tic–Phe–Phe–OH (TIPP) or morphine stimulation. Stimulation of the δ receptor with ligands leads to the phosphorylation of PKCδ, which acts upstream of EGFR transactivation and is needed for the release of the EGFR‐activating factor, whereas β‐arrestin2 was found to act downstream of the EGFR transactivation. Moreover, we demonstrated that coupling of the PKCδ/EGFR/β‐arrestin2 transactivation pathway to δ receptor‐mediated ERK1/2 activation was ligand‐specific and the Ser³⁶³ of δ receptors was crucial for ligand‐specific implementation of this ERK1/2 activation pathway.

Conclusions and Implications

The δ receptor‐mediated activation of ERK1/2 is via ligand‐specific transactivation of EGFR. This study adds new insights into the mechanism by which δ receptors activate ERK1/2.

Abbreviations

DPDPE

[D‐Pen2, D‐Pen5] enkephalin

HB‐EGF

heparin‐binding EGF‐like growth factor

IGFR

insulin‐like growth factor receptor

NG108‐15

cell mouse neuroblastoma x rat glioma hybrid cell

RTK

receptor tyrosine kinase

TIPP

H‐Tyr‐Tic‐Phe‐Phe‐OH

     

Selective enhancement of contractions to α1-adrenergic receptor activation in the aorta of mice with sickle cell disease

Sickle cell disease (SCD), the most common inherited hematologic disorder in the United States and the most common single gene disorder in the world, causes substantial morbidity and mortality. The major pathobiologic processes that underlie SCD include vaso-occlusion, inflammation, procoagulant processes, hemolysis, and altered vascular reactivity. The present study examined the vasoactive response to a-adrenergic activation in a murine model of SCD. Isolated aortas from sickle mice as compared with wild-type mice exhibit heightened contractions to norepinephrine and phenylephrine; such responses were completely blocked by an a1-receptor antagonist, prazosin. Aortas from either group exhibited comparable contractile responses to potassium chloride and the thromboxane agonist U46619 and no contractile response to an a2-adrenergic receptor agonist, UK14304. We conclude that there is an exaggerated vasoconstrictive response to a1-receptor agonists in SCD. Because sickle crisis is induced by diverse forms of stress, the latter attended by increased adrenergic activity, our findings may be relevant to the occurrence of sickle crisis. We also suggest that such heightened reactivity may contribute to vaso-occlusive processes that underlie ischemic injury in SCD. Finally, our findings urge caution in the use of phenylephrine in patients with SCD.     

Celecoxib potentially inhibits metastasis of lung cancer promoted by surgery in mice,via suppression of the PGE2-modulated β-catenin pathway

Surgery is the major treatment method for non-small cell lung cancer. It has been reported that plasma PGE2 level is increased following surgery and stress which promotes lung cancer metastasis. In the present study, two animal models were used to confirm the effects of exogenous and endogenous prostaglandin E2 (PGE2) on metastasis of lung cancer cells. We found that both PGE2 level and A549 metastasis were enhanced in mice with unilateral pulmonary resection following tail vein injection of lung cancer A549 cells. Both endogenous PGE2 level and pulmonary metastatic nodules were significantly reduced by celecoxib. A549 metastases were increased in mice after exogenous PGE2 injection. In the animal models, celecoxib inhibited lung cancer cell metastasis induced by exogenous PGE2. Therefore, we focused on the effects of celecoxib on the downstream pathway of PGE2 in vitro and found that celecoxib inhibited PGE2-induced A549 migration and invasion, which were evaluated by wound healing and Transwell experiments. The expression of protein and mRNA of MMP9 and E-cadherin following treatment with PGE2 were suppressed and increased by celecoxib, respectively; however, MMP2 showed no change. A549 cell invasion and up-regulation of the expression of MMP9 and down-regulation of E-cadherin induced by PGE2 were inhibited by FH535, an inhibitor of β-catenin. Deletion of β-catenin by siRNA abrogated celecoxib-induced inhibition of MMP9 up-regulation and E-cadherin down-regulation by treatment of PGE2. Furthermore, we found that the level of β-catenin together with GSK-3β phosphorylation was inhibited by celecoxib. In conclusion, celecoxib inhibits metastasis of A549 cells in the circulation enhanced by PGE2 after surgery by not only inhibiting endogenous PGE2 expression, but also by suppression downstream of PGE2 via the GSK-3β-β-catenin pathway.