Non-steroidal anti-inflammatory drugs to potentiate chemotherapy effects: from lab to clinic

Role of 12-lipoxygenase in regulation of ovarian cancer cell proliferation and survival

PURPOSE

Eicosanoid-related enzymes have been implicated in the pathogenesis of various cancers. Little is known about the relevance of lipoxygenase pathway to ovarian cancer growth. In this study, we examined the role of 12-lipoxygenase (12-LOX), the main human 12-HETE generating enzyme, in the regulation of proliferation and survival in epithelial ovarian cancer.

METHODS

Immunohistological analysis of 12-LOX expression in high-grade serous ovarian carcinoma and normal ovarian epithelium tissues was performed. The presence of 12-LOX-12-HETE system was confirmed in two epithelial ovarian cancer (EOC) cell lines, OVCAR-3 and SK-OV-3, using RT-PCR, Western blot and LC/MS analysis. The effects of N-benzyl-N-hydroxy-5-phenyl-pentanamide (BMD-122), a specific 12-LOX inhibitor, on cell growth, survival, apoptosis, and cell signaling were determined.

RESULTS

We found that a significantly higher level of 12-LOX expression in high-grade serous ovarian carcinoma compared to normal ovarian epithelium. OVCAR-3 and SK-OV-3 were found to express high level of 12-LOX mRNA and protein. Both EOC increased their 12-HETE production when incubated with arachidonic acid. BMD-122 inhibited the EOC growth in a dose-dependent fashion. Purified 12-HETE significantly reversed such inhibitory effects of BMD-122. In addition, BMD-122 blocked the MAPK signaling pathway by inhibiting the phosphorylation of ERK and induced a ~20-30% increase in the EOC apoptosis. Down-regulation of the 12-LOX expression using 12-LOX siRNA also resulted in markedly reduction in cell growth.

CONCLUSIONS

These data suggest that 12-LOX is involved in the regulation of ovarian cancer cell growth and survival and is a potential new therapeutic target.

A sulindac analogue is effective against malignant pleural effusion in mice

OBJECTIVES

To examine whether a sulindac derivative (C-18) with previously reported anti-angiogenic properties limits malignant pleural effusion (MPE) formation in mice.

METHODS

MPE was generated by intrapleural injection of murine adenocarcinoma cells in C57BL/6 mice. Animals were divided into three groups, a control group and two treatment groups receiving intraperitoneally a daily dose of either 1 mg or 2 mg of C-18 for a total of 12 doses. Mice were sacrificed on day 14.

MEASUREMENTS AND MAIN RESULTS

Pleural fluid volume and the number of pleural tumor implantations were measured. Tumor angiogenesis, pleural vascular permeability and the host inflammatory response were also assessed. C-18 significantly limited pleural fluid formation and inhibited intrapleural tumor dissemination. The mean±SEM pleural fluid volume was 758±63 μl for the control group, compared to 492±120 μl (p=0.042) and 279±77 μl (p<0.001) for the low dose and high dose group of C-18, respectively. Control group animals had 6.2±1 intrapleural tumors, while C-18 treated animals had 3.1±0.8 (p=0.014) and 3±0.7 (p=0.009) for the low and high dose respectively. In addition C-18 significantly suppressed pleural vascular permeability. No significant difference in tumor angiogenesis and inflammatory response was observed, while there was also no measurable effect in tumor cell apoptosis and proliferation in vitro and in vivo.

CONCLUSIONS

C-18 halted experimental MPE formation and intrapleural tumor dissemination, through down-regulation of pleural vascular permeability.

Docosahexaenoic acid reverts resistance to UV-induced apoptosis in human keratinocytes: involvement of COX-2 and HuR

The dramatic increase in the incidence of nonmelanoma skin cancer over the last decades has been related to the augmented exposure to ultraviolet (UV) radiation (UVR). It is known that apoptosis is induced as a protective mechanism after the acute irradiation of keratinocytes, whereas apoptotic resistance and carcinogenesis may follow the chronic exposure to UVR. We found that not all the human keratinocytes lines studied underwent apoptosis following acute exposure to UVR (10-60 mJ/cm(2)). Whereas UVR induced apoptosis in the HaCaT cells, NCTC 2544 and nr-HaCaT cells showed apoptosis resistance. The cytokeratin pattern of the apoptosis-resistant cells indicated that they possessed a degree of differentiation lower than that of HaCaT cells. They also showed an enhanced expression of cyclooxygenase-2 (COX-2), an early marker of carcinogenesis in various tissues, including skin. n-3 polyunsaturated fatty acids have drawn increasing interest as nutritional factors with the potential to reduce UVR carcinogenesis, and since they are apoptosis inducers and COX-2 inhibitors in cancer cells, we investigated the ability of n-3 polyunsaturated fatty acids to influence the resistance to UVR-induced apoptosis in keratinocytes. We observed that docosahexaenoic acid (DHA) reverted the resistance of nr-HaCaT cells to UVR-induced apoptosis, increasing the Bax/Bcl-2 ratio and caspase-3 activity, and reduced COX-2 levels by inhibiting the expression of the human antigen R (HuR), a known COX-2 mRNA stabilizer in keratinocytes. The transfection of nr-HaCaT cells with HuR siRNA mimicked the proapoptotic effect of DHA. Overall, our findings further support the role of DHA as a suitable anticarcinogenic factor against nonmelanoma skin cancers.

Wound healing after trauma may predispose to lung cancer metastasis: review of potential mechanisms

Inflammatory oncotaxis, the phenomenon in which mechanically injured tissues are predisposed to cancer metastases, has been reported for a number of tumor types, but not previously for histologically proven lung cancer. We review clinical and experimental evidence and mechanisms that may underlie inflammatory oncotaxis, and provide illustrative examples of two patients with squamous cell carcinoma of the lung who developed distant, localized metastatic disease at sites of recent physical trauma. Trauma may predispose to metastasis through two distinct, but not mutually exclusive, mechanisms: (1) physical trauma induces tissue damage and local inflammation, creating a favorable environment that is permissive for seeding of metastatic cells from distant sites; and/or (2) micrometastatic foci are already present at the time of physical injury, and trauma initiates changes in the microenvironment that stimulate the proliferation of the metastatic cells. Further exploration of post-traumatic inflammatory oncotaxis may elucidate fundamental mechanisms of metastasis and could provide novel strategies to prevent cancer metastasis.

Transcript profiling identifies novel key players mediating the growth inhibitory effect of NS-398 on human pancreatic cancer cells

Pancreatic cancer is one of the most aggressive human malignancies with an increasing incidence worldwide. Despite an increase in the number of systemic treatments available for pancreatic cancer, the impact of therapy on the clinical course of the disease has been modest, underscoring an urgent need for new therapeutic options. Although selective cyclooxygenase-2 inhibitors have been demonstrated to have cancer-preventive effects, the mechanism of their effects is not clearly known. Moreover, there have been no unbiased studies to identify novel molecular targets of NS-398 regarding pancreatic cancer. Here we undertook a gene expression profiling study to identify novel molecular targets modulating the growth inhibitory effects of NS-398 on pancreatic cancer cell lines. Our mRNA-based gene expression results showed that the growth inhibitory effect of NS-398 was accompanied with an activation of G1/S and G2/M cell cycle regulation, P53 signalling, apoptotic, aryl hydrocarbon receptor and death receptor signalling pathways. Moreover, we reported, for the first time, that the growth inhibitory effect of NS-398 is mediated by down-regulation of RRM2, CTGF, MCM2 and PCNA and up-regulation of NAG-1 in all cell lines.

Interaction of copper(II) with the non-steroidal anti-inflammatory drugs naproxen and diclofenac: synthesis, structure, DNA- and albumin-binding

Copper(II) complexes with the non-steroidal anti-inflammatory drugs (NSAIDs) naproxen and diclofenac have been synthesized and characterized in the presence of nitrogen donor heterocyclic ligands (2,2'-bipyridine, 1,10-phenanthroline or pyridine). Naproxen and diclofenac act as deprotonated ligands coordinated to Cu(II) ion through carboxylato oxygens. The crystal structures of (2,2'-bipyridine)bis(naproxenato)copper(II), 1, (1,10-phenanthroline)bis(naproxenato)copper(II), 2 and bis(pyridine)bis(diclofenac)copper(II), 4 have been determined by X-ray crystallography. The UV study of the interaction of the complexes with calf-thymus DNA (CT DNA) has shown that the complexes can bind to CT DNA with (2,2'-bipyridine)bis(naproxenato)copper(II) exhibiting the highest binding constant to CT DNA. Competitive study with ethidium bromide (EB) indicates that the complexes can displace the DNA-bound EB suggesting strong competition with EB. The cyclic voltammograms of the complexes recorded in the presence of CT DNA have shown that the complexes can bind to CT DNA by the intercalative binding mode which has also been verified by DNA solution viscosity measurements. The NSAID ligands and their complexes exhibit good binding propensity to human or bovine serum albumin protein having relatively high binding constant values. The biological properties of the previously reported complexes [Cu(2)(naproxenato)(4)(H(2)O)(2)], [Cu(2)(diclofenac)(4)(H(2)O)(2)] and [Cu(naproxenato)(2)(pyridine)(2)(H(2)O)] have been also evaluated. The dinuclear complexes exhibit similar affinity for CT DNA as the 2,2'-bipyridine or 1,10-phenanthroline containing complexes. The pyridine containing complexes exhibit the lowest affinity for CT DNA and the lowest ability to displace EB from its EB-DNA complex.

Synthesis, biological evaluation, and docking studies of novel heterocyclic diaryl compounds as selective COX-2 inhibitors

Three novel series of diaryl heterocyclic derivatives bearing the 2-oxo-5H-furan, 2-oxo-3H-1,3-oxazole, and 1H-pyrazole moieties as the central heterocyclic ring were synthesized and their in vitro inhibitory activities on COX-1 and COX-2 isoforms were evaluated using a purified enzyme assay. The 2-oxo-5H-furan derivative 6b was identified as potent COX inhibitor with selectivity toward COX-1 (COX-1 IC(50)=0.061 microM and COX-2 IC(50)=0.325 microM; selectivity index (SI)=0.19). Among the 1H-pyrazole derivatives, 11b was found to be a potent COX-2 inhibitor, about 38 times more potent than Rofecoxib (COX-2 IC(50)=0.011 microM and 0.398 microM, respectively), but showed no selectivity for COX-2 isoform. Compound 11c demonstrated strong and selective COX-2 inhibitory activity (COX-1 IC(50)=1 microM, COX-2 IC(50)=0.011 microM; SI= approximately 92). Molecular docking studies of compounds 6b and 11b-d into the binding sites of COX-1 and COX-2 allowed to shed light on the binding mode of these novel COX inhibitors.

Effect of goniothalamin on the development of Ehrlich solid tumor in mice

In this work the antiproliferative activity of goniothalamin (1), both in racemic and in its enantiomeric pure forms, in a solid tumor experimental model using laboratory animals is described. The antiedematogenic activity displayed by racemic 1 in the carrageenan edema model in mice together with the reduction of Ehrlich solid tumor model suggest a relationship between anticancer and antiinflammatory activities with the antiinflammatory activity favoring the antiproliferative activity itself.

Eicosanoids in inflammation and cancer: the role of COX-2

Eicosanoids, a family of oxygenated metabolites of eicosapolyenoic fatty acids, such as arachidonic acid, formed via the lipoxygenase, cyclooxygenase (COX) and epoxygenase pathways, play an important role in the regulation of various pathophysiological processes, including inflammation and cancer. COX-2, the inducible isoform of COX, has emerged as the key enzyme regulating inflammation, and promises to play a considerable role in cancer. Although NSAIDs have been in use for centuries, the COX-2 selective inhibitors - coxibs - have emerged as potent anti-inflammatory drugs with fewer gastric side effects. As COX-2 plays a major role in neoplastic transformation and cancer growth, by downregulating apoptosis and promoting angiogenesis, invasion and metastasis, coxibs have a potential role in the prevention and treatment of cancer. Recent studies indicate their possible application in overcoming drug resistance by downregulating the expression of MDR-1. However, the cardiac side effects of some of the coxibs have limited their application in treating various inflammatory disorders and warrant the development of COX-2 inhibitors without side effects. This review will focus on the role of COX-2 in inflammation and cancer, with an emphasis on novel approaches to the development of COX-2 inhibitors without side effects.

Changes in the gene expression profile of gastric cancer cells in response to ibuprofen: a gene pathway analysis

Nonsteroidal anti-inflammatory drugs possess antiproliferative activities that can affect cancer cells. The aim of this study was to examine the antiproliferative effects of ibuprofen on the MKN-45 cell line. Cells were treated with ibuprofen for 24, 48 or 72 h, and cell proliferation was evaluated by cell counting and [(3)H]-thymidine incorporation. Using microarray technology, we studied changes in the gene expression profiles over time after ibuprofen treatment. Ibuprofen induced a dose- and time-dependent reduction in cell number without altering cell viability. Genes involved in the 'biological oxidation' and 'G(1)/S checkpoint' pathways were the most significantly represented at 24 h, whereas genes involved in the 'cell cycle' and 'DNA replication' pathways were represented at 48 and 72 h. Genes associated with the 'apoptosis' pathway were also significantly represented at 72 h. Modulation of the expression of p53 and p53-induced genes (CDKN1A/p21 and GADD45), which are involved in the G(1)/S transition, suggested an effect of ibuprofen on cell-cycle progression. Using flow cytometry, we observed an early block in the G(1) phase of the cell cycle after ibuprofen treatment. In addition, P450 family transcripts were upregulated and intracellular reactive oxygen species (ROS) was increased following 12 h of ibuprofen treatment. Ibuprofen induced ROS, which resulted in cellular alterations that promoted a p53-dependent G(1) blockade. These findings suggest that ibuprofen exerts its antiproliferative actions through cell-cycle control and the induction of apoptosis. Both of these mechanisms appear to be independent of ibuprofen's anti-inflammatory effects.

Aspirin induces apoptosis in human leukemia cells independently of NF-kappaB and MAPKs through alteration of the Mcl-1/Noxa balance

Aspirin and other non-steroidal anti-inflammatory drugs induce apoptosis in most cell types. In this study we examined the mechanism of aspirin-induced apoptosis in human leukemia cells. We analyzed the role of nuclear factor-kappaB (NF-kappaB) and mitogen-activated protein kinases (MAPKs) pathways. Furthermore, we studied the changes induced by aspirin in some genes involved in the control of apoptosis at mRNA level, by performing reverse transcriptase multiplex ligation-dependent probe amplification (RT-MLPA), and at protein level by Western blot. Our results show that aspirin induced apoptosis in leukemia Jurkat T cells independently of NF-kappaB. Although aspirin induced p38 MAPK and c-Jun N-terminal kinase activation, selective inhibitors of these kinases did not inhibit aspirin-induced apoptosis. We studied the regulation of Bcl-2 family members in aspirin-induced apoptosis. Aspirin increased the mRNA levels of some pro-apoptotic members, such as BIM, NOXA, BMF or PUMA, but their protein levels did not change. In contrast, aspirin decreased the protein levels of Mcl-1. Interestingly, in the presence of aspirin the protein levels of Noxa remained high. This alteration of the Mcl-1/Noxa balance was also found in other leukemia cell lines and primary chronic lymphocytic leukemia cells (CLL). Furthermore, in CLL cells aspirin induced an increase in the protein levels of Noxa. Knockdown of Noxa or Puma significantly attenuated aspirin-induced apoptosis. These results indicate that aspirin induces apoptosis through alteration of the Mcl-1/ Noxa balance.

Effects of short-term celecoxib treatment in patients with invasive transitional cell carcinoma of the urinary bladder

High-grade invasive transitional cell carcinoma (InvTCC) kills >14,000 people yearly in the United States, and better therapy is needed. Cyclooxygenase-2 (Cox-2) is overexpressed in bladder cancer. Cox inhibitors have caused remission of InvTCC in animal studies, and cancer regression was associated with doubling of the apoptotic index in the tumor. The purpose of this study was to determine the apoptosis-inducing effects of celecoxib (a Cox-2 inhibitor) in InvTCC in humans. Patients (minimum of 10 with paired tumor samples) with InvTCC who had elected to undergo cystectomy were enrolled. The main study end point was induction of apoptosis in tumor tissues. Patients received celecoxib (400 mg twice daily p.o. for a minimum of 14 days) between the time of diagnosis [transurethral resection of bladder tumor (TURBT)] and the time of cystectomy (standard frontline treatment for InvTCC). Terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling assay and immunohistochemistry were done on TURBT and cystectomy samples. Of 13 cases treated with celecoxib, no residual invasive cancer was identified in 3 patients at the time of cystectomy (post celecoxib). Of the 10 patients with residual cancer, 7 had induction of apoptosis in their tumor. Induction of apoptosis was less frequent (3 of 13 cases; P < 0.04) in control patients not receiving a Cox inhibitor. Expression of vascular endothelial growth factor in the tumor cells decreased more frequently (P < 0.026) in the treated patients as compared with nontreated control cases. The biological effects of celecoxib treatment (increased apoptosis) justify further study of the antitumor effects of Cox-2 inhibitors in InvTCC.

Eicosanoids and cancer

Eicosanoids, including prostaglandins and leukotrienes, are biologically active lipids that have been implicated in various pathological processes, such as inflammation and cancer. This Review highlights our understanding of the intricate roles of eicosanoids in epithelial-derived tumours and their microenvironment. The knowledge of how these lipids orchestrate the complex interactions between transformed epithelial cells and the surrounding stromal cells is crucial for understanding tumour evolution, progression and metastasis. Understanding the molecular mechanisms underlying the role of prostaglandins and other eicosanoids in cancer progression will help to develop more effective cancer chemopreventive and/or therapeutic agents.

Inhibition of cyclooxygenase-2 impairs the expression of essential plasma cell transcription factors and human B-lymphocyte differentiation

Cyclooxygenase (Cox) inhibitors are among the most widely used and commonly prescribed medications. Relatively little is understood about their influence on human immune responses. Herein, we discovered a novel and important mechanism whereby non-steroidal anti-inflammatory drugs (NSAIDs) blunt human B-cell antibody production. We demonstrate that the Cox-2 selective small molecule inhibitors SC-58125 and NS-398 attenuate the production of human antibody isotypes including immunoglobulin M (IgM), IgG1, IgG2, IgG3 and IgG4. In addition, inhibition of Cox-2 significantly reduced the generation of CD38+ IgM+ and CD38+ IgG+ antibody-secreting cells. Interestingly, we discovered that inhibition of Cox-2 activity in normal human B cells severely reduced the messenger RNA and protein levels of the essential plasma cell transcription factor, Blimp-1. These observations were mirrored in Cox-2-deficient mice, which had reduced CD138+ plasma cells and a near loss of Blimp-1 expression. These new findings demonstrate a critical role for Cox-2 in the terminal differentiation of human B lymphocytes to antibody-secreting plasma cells. The use of NSAIDs may adversely influence the efficacy of vaccines, especially in the immunocompromised, elderly and when vaccines are weakly immunogenic.

Cyclooxygenase-2 immunohistochemistry in human melanoma: differences between results obtained with different antibodies

Several groups have reported that cyclooxygenase-2 (COX-2) expression is significantly enhanced in human melanomas, and that the expression of this protein may be useful as diagnostic and prognostic marker for the disease. At the same time, collective analysis of immunohistochemical data on the COX-2 expression in melanomas, presented by different researchers, shows a clear lack of consistency of reported results commonly assigned to differences in protocols used for the staining. This paper describes a study involving the parallel use of three different primary anti-COX-2 antibodies targeting different COX-2 epitopes. A surprising outcome is that although the three antibodies gave very consistent results for the COX-2 expression in keratinocytes, they showed significant differences in immunoreactivity for both melanocytic naevi and melanomas. This phenomenon has not been described before, and has implications for the selection of antibodies for studies on the diagnostic potential of COX-2 for melanoma.

Enhanced 5-fluorouracil cytotoxicity in high cyclooxygenase-2 expressing colorectal cancer cells and xenografts induced by non-steroidal anti-inflammatory drugs via downregulation of dihydropyrimidine dehydrogenase

PURPOSE

To prove that 5-FU cytotoxicity could be increased by combination with low-dose non-steroidal anti-inflammatory drugs (NSAIDs) (indomethacin or NS-398) in high cyclooxygenase-2- (COX-2) expressing cells and xenografts through the modulation of dihydropyrimidine dehydrogenase (DPD) mRNA expression and/or enzyme activity.

METHODS

HT-29 cells were grown on collagen IV coated plates (HT-29-C). The antiproliferative effect of 5-fluorouracil (5-FU) +/- NSAIDs was examined on non-COX-2 expressing HT-29 and COX-2-expressing HT-29-C cells by sulphorhodamine B assay. The COX-2 and DPD expressions were visualized by immunofluorescent staining, and prostaglandin E(2) levels were measured by ELISA kit. The HT-29 xenograft was established in SCID mice and treated with 5-FU +/- NSAIDs for 5 days. The tumor volume, enzyme activity, and DPD mRNA expression were investigated by caliper, radioenzymatic method, and real-time RT-PCR, respectively. The drug interaction was calculated for both combinations (5-FU + indomethacin and 5-FU + NS-398).

RESULTS

Collagen IV up-regulated significantly the COX-2 and DPD mRNA, and protein expressions, and also their enzyme activities in HT-29 cells. NSAIDs enhanced in a synergistic manner the cytotoxic effect of 5-FU treatment both in vitro and in vivo. Downregulation of DPD was observed after 5-FU monotherapy, but the combined effect of NSAIDs and 5-FU on DPD mRNA expression, and enzyme activity was superior to the effect of 5-FU alone.

CONCLUSIONS

Since 5-FU + NSAID treatment can alter the DPD enzyme activity resulting in an enhanced cytotoxic effect, further studies in clinical practice are warranted.

The effects of celecoxib, a COX-2 selective inhibitor, on acute inflammation induced in irradiated rats

The potential value of selective and non-selective COX-2 inhibitors in preventing some of the biochemical changes induced by ionizing radiation was studied in rats exposed to carrageenan-induced paw edema and 6-day-old air pouch models. The animals were exposed to different exposure levels of gamma-radiation, namely either to single doses of 2 and 7.5 Gy or a fractionated dose level of 7.5 Gy delivered as 0.5 Gy twice weekly for 7.5 weeks. The inflammatory response produced by carrageenan in irradiated rats was markedly higher than that induced in non-irradiated animals, and depended on the extent of irradiation. Celecoxib, a selective COX-2 inhibitor, in doses of 3, 5, 10, and 15 mg/kg was effective in reducing paw edema in irradiated and non-irradiated rats in a dose-dependent manner as well as diclofenac (3 mg/kg), a non-selective COX inhibitor. Irradiation of animals before the induction of the air pouch by an acute dose of 2 Gy led to a significant increase in leukocytic count, as well as in the level of interleukin-6 (IL-6), interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), LTB(4), PGE(2) (as an index of COX-2 activity), TXB(2) (as an index of COX-1 activity), and the plasma level of MDA. This increase in level of these parameters was more marked than that observed in the non-irradiated animals subjected to the inflammagen. The blood GSH level was not affected by the dose of irradiation used, whereas superoxide dismutase (SOD) activity was suppressed. In many respects, celecoxib (5 mg/kg) was as potent as diclofenac in decreasing the elevated levels of IL-6, IL-1beta, TNF-alpha, LTB(4), PGE(2), but lacked any significant effect on TXB(2) level. Since it is mostly selective for COX-2 with a rare effect on COX-1 enzyme, both drugs at the selected dose levels showed no effect on level of MDA, GSH, and SOD activity.

Multiple defects in negative regulation of the PKB/Akt pathway sensitise human cancer cells to the antiproliferative effect of non-steroidal anti-inflammatory drugs

Antitumorigenic effects of non-steroidal anti-inflammatory drugs (NSAIDs) are well established in several types of cancer disease. However, the mechanisms driving these processes are not understood in all details. In our study, we observed significant differences in sensitivity of cancer epithelial cell lines to COX-independent antiproliferative effects of NSAIDs. The prostate cancer cell line LNCaP, lacking both critical enzymes in the negative control of PKB/Akt activation, PTEN and SHIP2, was the most sensitive to these effects, as assessed by analysing the cell cycle profile and expression of cell cycle regulating proteins. We found that p53 protein and its signalling pathway is not involved in early antiproliferative action of the selected NSAID-indomethacin. RNAi provided evidence for the involvement of p21(Cip1/Waf1), but not GDF-15, in antiproliferative effects of indomethacin in LNCaP cells. Interestingly, we also found that indomethacin activated PKB/Akt and induced nuclear localisation of p21(Cip1/Waf1) and Akt2 isoform. Our results are in agreement with other studies and suggest that maintaining of the p21(Cip1/Waf1) level and its intracellular localisation might be influenced by Akt2. Knock-down of SHIP2 by RNAi in PTEN negative prostate and colon cancer cell lines resulted in higher sensitivity to antiproliferative effects of indomethacin. Our data suggest novel mechanisms of NSAIDs antiproliferative action in cancer epithelial cells, which depends on the status of negative regulation of the PKB/Akt pathway and the isoform-specific action of Akt2. Thus, unexpectedly, multiple defects in negative regulation of the PKB/Akt pathway may contribute to increased sensitivity to chemopreventive effects of these widely used drugs.

Phenolic compounds with radical scavenging and cyclooxygenase-2 (COX-2) inhibitory activities from Dioscorea opposita

Phytochemical studies of the chloroform soluble fraction of Dioscorea opposita resulted in the isolation of four new compounds, 3,5-dihydroxy-4-methoxybibenzyl (1), 3,3',5-trihydroxy-2'-methoxybibenzyl (2), 10,11-dihydro-dibenz[b,f]oxepin-2,4-diol (3), and 10,11-dihydro-4-methoxy-dibenz[b,f]oxepin-2-ol (4), together with an additional fifteen known compounds. The structures of 1-4 were elucidated by spectroscopic methods including 2D NMR. All of the nineteen isolated compounds were tested in the DPPH, superoxide anion radical scavenging assays and cyclooxygenases (COXs) inhibition assay. Of those, compounds 7, 9, 11, 12, 13, 15 and 18 exhibited radical scavenging activities and compounds 2, 3, 8, 13, 15 and 16 showed selective inhibitory activities against COX-2.

NS-398, ibuprofen, and cyclooxygenase-2 RNA interference produce significantly different gene expression profiles in prostate cancer cells

Cyclooxygenase-2 (COX-2) plays a significant role in tumor development and progression. Nonsteroidal anti-inflammatory drugs (NSAID) exhibit potent anticancer effects in vitro and in vivo by COX-2-dependent and COX-2-independent mechanisms. In this study, we used microarray analysis to identify the change of expression profile regulated by a COX-2-specific NSAID NS-398 (0.01 and 0.1 mmol/L), a nonspecific NSAID ibuprofen (0.1 and 1.5 mmol/L) and RNA interference (RNAi)-mediated COX-2 inhibition in PC3 prostate cancer cells. A total of 3,362 differentially expressed genes with 2-fold change and P<0.05 were identified. Low concentrations of NSAIDs and COX-2 RNAi altered very few genes (1-3%) compared with the higher concentration of NS-398 (17%) and ibuprofen (80%). Ingenuity Pathway Analysis was used for distributing the differentially expressed genes into biological networks and for evaluation of functional significance. The top 3 networks for both NSAIDs included functional categories of DNA replication, recombination and repair, and gastrointestinal disease. Immunoresponse function was specific to NS-398, and cell cycle and cellular movement were among the top functions for ibuprofen. Ingenuity Pathway Analysis also identified renal and urologic disease as a function specific for ibuprofen. This comprehensive study identified several COX-2-independent targets of NSAIDs, which may help explain the antitumor and radiosensitizing effects of NSAIDs. However, none of these categories were reflected in the identified networks in PC3 cells treated with clinically relevant low concentrations of NS-398 and ibuprofen or with COX-2 RNAi, suggesting the benefit to fingerprinting preclinical drug concentrations to improve their relevance to the clinical setting.

Anti-Inflammatory Agents for Cancer Therapy

Inflammation is closely linked to cancer, and many anti-cancer agents are also used to treat inflammatory diseases, such as rheumatoid arthritis. Moreover, chronic inflammation increases the risk for various cancers, indicating that eliminating inflammation may represent a valid strategy for cancer prevention and therapy. This article explores the relationship between inflammation and cancer with an emphasis on epidemiological evidence, summarizes the current use of anti-inflammatory agents for cancer prevention and therapy, and describes the mechanisms underlying the anti-cancer effects of anti-inflammatory agents. Since monotherapy is generally insufficient for treating cancer, the combined use of anti-inflammatory agents and conventional cancer therapy is also a focal point in discussion. In addition, we also briefly describe future directions that should be explored for anti-cancer anti-inflammatory agents.

The role of non-steroidal anti-inflammatory drugs in the risk of development and treatment of hematologic malignancies

Non-steroidal anti-inflammatory drugs (NSAIDs) comprise the group of structurally diverse but similarly acting compounds that are used for relieving signs and symptoms of inflammation, especially in treatment of rheumatic diseases. Recent reports suggested potential association between regular use of NSAIDs and the risk of development of hematological malignancies. However, the data distinctly differ depending on type of NSAID used, period of its administration and type of malignancy. Regular use of aspirin and other NSAIDs was shown to correlate with reduced risk of lymphoid malignancies. Frequent use of aspirin was found to be associated with decreased risk of acute leukemia (AL) development. In contrast, correlation between long-term acetaminophen usage and increased incidence of AL and multiple myeloma (MM) was indicated. On the other hand, NSAIDs were found to exert anti-cancer effects, inhibiting proliferation and invasive growth or inducing cell apoptosis in several tumors, including hematologic malignancies. One of those agents, non-cyclooxygenase 2-inhibiting R-enantiomer of etodolac (SDX-101), exerts cytotoxic effects against chronic lymphocytic leukemia (CLL) and MM cells, and is currently investigated in phase II clinical trial in CLL. The indole-pyran analogue of SDX-101, SDX-308 (CEP-18082), showed more potent cytotoxicity than SDX-101 against MM cells and inhibited osteoclast formation and activity of mature osteoclasts. Thus, SDX-308 may be an ideal agent for bone disease in MM and related diseases. Another analogue of SDX-101, SDX-309, showed also significant anti-tumor activity in first preclinical studies. The potential role of NSAIDs in prevention and treatment of hematologic malignancies is the subject of this review.

Photodynamic therapy of superficial nasal planum squamous cell carcinomas in cats: 55 cases

BACKGROUND

Squamous cell carcinomas (SCCs) are common skin tumors in cats. We investigated photodynamic therapy (PDT) using the photosensitizing agent 5-aminolaevulinic acid (5-ALA) topically and a high-intensity red light source.

HYPOTHESIS

PDT is a safe and effective treatment for feline SCCs.

ANIMALS

Fifty-five client-owned cats with superficial nasal planum SCCs.

METHODS

Prospective, uncontrolled clinical trial. PDT was performed using topical 5-ALA and light of peak wavelength 635 nm. Adverse effects, response, and tumor control were evaluated.

RESULTS

53/55 (96%) cats responded to therapy, and there was a complete response in 47/55 (85%). Six cats (11%) had a partial response. Of the 47 cats with complete response to a single treatment, 24 recurred (51%), with a median time to recurrence of 157 days (95% confidence interval, 109-205 days). Repeat PDT was performed in 22 cats, and at a median follow-up of 1,146 days, 23 (45%) cats were alive and disease free, 17 (33%) had to be euthanized due to tumor recurrence, and 11 (22%) were euthanized for other reasons. Only transient mild local adverse effects were observed after treatment.

CONCLUSIONS AND CLINICAL IMPORTANCE

PDT using 5-ALA and a red light source was safe, well tolerated, and effective in the treatment of superficial nasal planum SCCs of cats and offers an alternative to conventional therapy. Although initial response rates were high, this treatment did not lead to a durable remission or cure in all cases.

Pro-apoptotic effect of nonsteroidal anti-inflammatory drugs on synovial fibroblasts

Rheumatoid arthritis (RA) is a systemic inflammatory disease that mainly affects the articular synovial tissues. Although the etiology of RA has not yet been elucidated, physical and biochemical inhibition of synovial hyperplasia, which is the origin of articular destruction, may be an effective treatment for RA. Nonsteroidal anti-inflammatory drugs (NSAIDs) have long been used for the treatment of RA. The mechanism of action of NSAIDs generally involves the inhibition of cyclooxygenase (COX) at sites of inflammation. Thus, NSAIDs were not generally considered to have a so-called anti-rheumatic effect, including inhibition of progressive joint destruction and induction of remission. However, certain conventional NSAIDs and celecoxib, a selective COX-2 inhibitor, have been reported to inhibit synovial hyperplasia by inducing the apoptosis of human synovial fibroblasts. Therefore, it has been suggested that such NSAIDs may not only have an anti-inflammatory effect but also an anti-rheumatic effect. In this review, we summarize findings about the pro-apoptotic effect, in other words, anti-proliferative effect of NSAIDs on synovial fibroblasts from patients with RA.

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 (<or=5 micromol/L) inhibited proliferation of COX-2-expressing HT1376 cells in soft agar and modified monolayer cell culture conditions in a COX-2-dependent manner. COX-2 expression, however, did not always correlate with response to celecoxib. TCCSUP cells that express COX-2 were minimally affected by celecoxib, and UMUC3 cells that lack COX-2 expression were modestly inhibited by the drug. When UMUC3(Cox-2/Tet) cells overexpressing COX-2 under the control of tetracycline-inducible promoter were treated with celecoxib in modified monolayer cell culture, growth inhibition was found to be associated with changes in the expression of pRb. Not surprisingly, the proliferation of all cell lines was inhibited by excessively high concentrations of celecoxib. In conclusion, the modified culture conditions allowed detection of COX-2-dependent and COX-2-independent growth-inhibitory activity of celecoxib in urinary bladder cancer cells.

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 G(1) 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 (3mg/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.