COX-2 inhibitor celecoxib prevents chronic morphine-induced promotion of angiogenesis, tumour growth, metastasis and mortality, without compromising analgesia. Br J Cancer. 2007;97:1523-1531. [PMID: 17971769 PMCID: PMC2360252 DOI: 10.1038/sj.bjc.6604057]

Anticancer effect of celecoxib via COX-2 dependent and independent mechanisms in human gastric cancers cells

Cyclooxygenase-2 (COX-2) inhibitors cause growth inhibition of human gastric carcinoma cells, but it remains unclear whether this is both COX-2 dependent and independent. The related mechanisms remain to be determined. Both low COX-2 expressing gastric carcinoma and high COX-2 expressing gastric carcinoma cells were used to study the effect and mechanisms of celecoxib on gastric carcinoma cell growth. Celecoxib resulted in comparable growth inhibition in AGS cells with stable transfections of small interfering RNA (siRNA) against COX-2 (SAC) and negative control vector (NC) cells. Simultaneously, celecoxib resulted in significant reduction of Bcl-2 and significant increase of p21(WAF1) and p27(KIP1) in SAC and NC cells. The present study shows that celecoxib causes growth inhibition of gastric carcinoma cells by decreasing Bcl-2 of cyclooxygenase-2-dependent pathway, and by increasing p21(WAF1) and p27(KIP1) of cyclooxygenase-2-independent pathway. These data extend our knowledge on the effect and mechanisms of celecoxib-induced inhibition of gastric carcinoma cell growth.

Lymphoblastic T-cell lymphoma in mice is unaffected by Celecoxib as single agent or in combination with cyclophosphamide

Celecoxib, an inhibitor of cyclooxygenase-2, is a promising novel antitumor agent with pleitropic mechanisms of action. Whereas this drug induces growth arrest and apoptosis of B-lymphoma cells, its effect against aggressive T-cell neoplasms remains to be studied. We therefore evaluated Celecoxib therapy of immunocompetent mice transplanted with lymphoblastic T-cell lymphomas. Oral Celecoxib in clinically relevant and non-toxic doses did not affect the degree of hypersplenism or the number of viable lymphoma cells. The clinical deterioration of Celecoxib-treated mice was not different from untreated controls. The impact of adding Celecoxib (60 mg/kg) to cyclophosphamide (200 mg/kg x 1, i.p.) was assessed but showed no benefit compared to cyclophosphamide alone. Thus, Celecoxib lacks effect against lymphoblastic T-cell lymphoma in mice.

Treatment with cyclooxygenase-2 inhibitors enables repeated administration of vaccinia virus for control of ovarian cancer

Metastatic ovarian cancer is the leading cause of death among women with gynecologic malignancies in the United States. The lack of effective treatment for patients with advanced ovarian cancer warrants development of innovative therapies. Cancer therapy using oncolytic viruses represents a promising new approach for controlling tumors. Vaccinia virus has been shown to preferentially infect tumor cells but not normal tissue. However, oncolytic therapy using recombinant viruses faces the limitation of viral clearance due to generation of neutralizing antibodies. In the current study, we found that cyclooxygenase-2 (Cox-2) inhibitors circumvented this limitation, enabling repeated administration of vaccinia virus without losing infectivity. We quantified the antivaccinia antibody response using enzyme-linked immunosorbent assay (ELISA) and neutralization assays to show that treatment of Cox-2 inhibitors inhibited the generation of neutralizing antibodies. Furthermore, we showed that combination treatment of Cox-2 inhibitors with vaccinia virus was more effective that either treatment alone in treating MOSEC/luc tumor-bearing mice. Thus, the combination of Cox-2 inhibitors and vaccinia virus represents a potential innovative approach to controlling ovarian tumors.

Morphine-induced early delays in wound closure: involvement of sensory neuropeptides and modification of neurokinin receptor expression

Dose-limiting side effects of centrally acting opioid drugs have led to the use of topical opioids to reduce the pain associated with chronic cutaneous wounds. However, previous studies indicate that topical morphine application impairs wound healing. This study was designed to elucidate the mechanisms by which morphine delays wound closure. Rats were depleted of sensory neuropeptides by treatment with capsaicin, and full-thickness 4-mm diameter wounds were excised from the intrascapular region. Wounds were treated topically twice daily with 5mM morphine sulfate, 1mM substance P, 1mM neurokinin A, or 5mM morphine combined with 1mM substance P or neurokinin A and wound areas assessed. During closure, wound tissue was taken 1, 3, 5, and 8 days post-wounding from control and morphine-treated rats and immunostained for neurokinin receptors and markers for macrophages, myofibroblasts, and vasculature. Results obtained from capsaicin-treated animals demonstrated a significant delay in the early stages of wound contraction that was reversed by neuropeptide application. Treatment of capsaicin-treated rats with topical morphine did not further delay wound closure, suggesting that topical opioids impair wound closure via the inhibition of peripheral neuropeptide release into the healing wound. Morphine application altered neurokinin-1 and neurokinin-2 receptor expression in inflammatory and parenchymal cells essential for wound healing in a cell-specific manner, demonstrating a direct effect of morphine on neurokinin receptor regulation within an array of cells involved in wound healing. These data provide evidence indicating a potentially detrimental effect of topical morphine application on the dynamic wound healing process.

Endogenous opiates and behavior: 2007

This paper is the thirtieth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2007 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.

Celecoxib inhibited activation of NF-kB and expression of NF-kB P65 protein in HepG2 cells

AIM: To investigate effects of COX-2 inhibitor celecoxib on activation of nuclear factor-kappa B (NF-kB) and on protein expression of NF-kB P65 in human liver cancer cell line HepG2.

METHODS: HepG2 cells were treated with various concentrations of celecoxib. The NF-kB DNA binding activation was detected using electrophoresis mobility shift assay and protein expression of NF-kB p65 was determined using western blotting in HepG2 cells.

RESULTS: After HepG2 cells were treated with different concentrations of celecoxib (25 and 50 μmol/L, respectively), NF-kB DNA binding activation were significantly reduced (t = 12.58, P = 0.000; t = 17.97, P = 0.000) and protein expression of NF-kB p65 were significantly inhibited in celecoxib-treated HepG2 cells as compared with those in the empty control group (t = 4.24, P = 0.013; P = 6.38, P = 0.003).

CONCLUSION: Activation of NF-kB and expression of NF-kB p65 protein in HepG2 cells are effectively inhibited by celecoxib.

Opioid-induced regulation of µ-opioid receptor gene expression in the MCF-7 breast cancer cell line

The aim of the study was to investigate the presence of opioid receptor types in human breast adenocarcinoma MCF-7 cells and to characterize the changes in MOR expression induced by opioid agonist and antagonist treatment. We have shown that all three types of opioid receptors, but predominantly MOR, are expressed in MCF-7 cells. Selective MOR agonists, morphine, endomorphin-1, and endomorphin-2 downregulated MOR mRNA levels in a concentration- and time-dependent manner, but the effect produced by endomorphins was much stronger. Downregulation was blocked by the opioid antagonist naloxone. Naloxone alone produced a slight increase in MOR gene expression. Immunoblotting with antiserum against MOR-1 confirmed these results at the protein level. The results of our study indicate that, in MCF-7 cells, MOR gene expression is downregulated by opioid agonists and upregulated by opioid antagonists. We propose that the opioid-induced regulation of MOR mRNA expression is mediated by reduced binding of the transcription factors NFκB and AP-1 to the promoter region on the MOR gene.