A comparison of the effectiveness of selected non-steroidal anti-inflammatory drugs and their derivatives against cancer cells in vitro

Assessment of the cytotoxic, genotoxic, and apoptotic potential of flurbiprofen in HeLa and HepG2 cell lines

In the literature, the anticancer potential of flurbiprofen isn't fully understood. In this study, the cytotoxic, genotoxic, and apoptotic effects of flurbiprofen were evaluated in human cervical and liver cancer cells. Cytotoxicity was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and it was observed that cytotoxicity increased in a concentration- and time-dependent manner. Genotoxicity was determined using alkaline Comet assay. DNA damage increased in a concentration-dependent manner. Early apoptosis was evaluated using real-time polymerase chain reaction, and it was found that apoptotic gene levels increased while antiapoptotic gene levels decreased. Late apoptosis and cell cycle analyzes were determined using flow cytometry. No evidence of late apoptosis was observed, and no significant arrest was found in the cell cycle. In conclusion, it seems that flurbiprofen has a cytotoxic, genotoxic, and apoptotic effects in both human cancer cell lines. Moreover, the findings indicate that flurbiprofen is effective at the gene level and induces apoptosis with an intracellular pathway.

New drugs are not enough‑drug repositioning in oncology: An update

Drug repositioning refers to the concept of discovering novel clinical benefits of drugs that are already known for use treating other diseases. The advantages of this are that several important drug characteristics are already established (including efficacy, pharmacokinetics, pharmacodynamics and toxicity), making the process of research for a putative drug quicker and less costly. Drug repositioning in oncology has received extensive focus. The present review summarizes the most prominent examples of drug repositioning for the treatment of cancer, taking into consideration their primary use, proposed anticancer mechanisms and current development status.

Primaquine derivatives: Modifications of the terminal amino group

Numerous modifications of the well-known antimalarial drug primaquine, both at the quinoline ring and at the primary amino group, have been reported, mostly to obtain antimalarial agents with improved bioavailability, reduced toxicity and/or prolonged activity. Modifications of the terminal amino group were made with the main idea to prevent the metabolic pathway leading to inactive and toxic carboxyprimaquine (follow-on strategy), but also to get compounds with different activity (repurposing strategy). The modifications undertaken until 2009 were included in a review published in the same year. The present review covers various classes of primaquine N-derivatives with diverse biological profiles, prepared in the last decade by our research group as well as the others. We have summarized the synthetic procedures applied for their preparation and discussed the main biological results. Several hits for the development of novel antiplasmodial, anticancer, antimycobacterial and antibiofilm agents were identified.

Association of nonsteroidal anti-inflammatory drugs and aspirin use and the risk of head and neck cancers: a meta-analysis of observational studies

Purpose

Nonsteroidal anti-inflammatory drugs (NSAIDs), including aspirin, have emerged as the potential chemopreventive agents for a number of cancer types, however, previous studies of head and neck cancers (HNC) have yielded inconclusive results. We performed a meta-analysis of observational studies to quantitatively assess the association between NSAIDs use and the risk for HNC.

Methods

We searched Pubmed, Embase, Google scholar, and Cochrane library for relevant studies that were published in any language, from January 1980 to April 2016. We pooled the odds ratio (OR) from individual studies and performed subgroup, heterogeneity, and publication bias analyses.

Results

A total of eleven studies (eight case-control studies and three cohort studies), involving 370,000 participants and 10,673 HNC cases contributed to this meta-analysis. The results of these studies suggested that neither use of overall NSAIDs (OR=0.95; 95% CI, 0.81-1.11), aspirin (OR=0.93; 95% CI, 0.79-1.10), nor nonsteroidal NSAIDs (OR=0.92; 95% CI, 0.76-1.10) were associated with HNC risk. Similar nonsteroidal results were observed when stratified by HNC sites, study design, sample size, and varied adjustment factors. However, we found significant protective effect of ibuprofen (OR=0.85; 95% CI, 0.72-0.99) and long-term aspirin use (≧5years) (OR=0.75; 95% CI, 0.65-0.85) on HNC risk, with low heterogeneity and publication bias.

Conclusions

Our meta-analysis results do not support the hypothesis that overall use of NSAIDs significant reduces the risk of HNC. Whereas, we cannot rule out a modest reduction in HNC risk associated with ibuprofen and long-term aspirin use.

Aspirin inhibits growth of ovarian cancer by upregulating caspase-3 and downregulating bcl-2

The aim of the present study was to investigate the effect and mechanism of different concentrations of aspirin in inhibiting the ovarian cancer of p53N236S gene knock-in mice. In total, 28 male p53S mice, with an age range of 4–6 weeks and weight of 20–25 g were selected. The animals were transplanted with SKOV3 cells to establish subdermal human ovarian cancer. The mice were randomly divided into different groups according to the aspirin concentrations (mmol/l) used, i.e., 0, 1, 2 and 3. Subsequently, intraperitoneal injection was performed once every two days for 3 weeks. The tumor volume, lifetime, tumor cell proliferation inhibition rates, caspase-3 protein and bcl-2 protein expression of the four groups were analyzed and compared. Following aspirin treatment for 1, 2 and 3 weeks, the tumor volume of the 3 mmol/l aspirin group was significantly smaller than the other groups (P<0.05). The higher concentration of aspirin led to a smaller tumor size (P<0.05). The cell proliferation inhibition rate of the 3 mmol/l aspirin group was significantly larger than that of other groups (P<0.05). The relative expression level of caspase-3, bcl-2 protein of the 3 mmol/l aspirin group was significantly improved and reduced, respectively. In conclusion, aspirin can inhibit the growth of ovarian cancer of p53S rats due to its upregulation of the expression of caspase-3 protein and downregulation of the expression of bcl-2 protein.

Non-steroidal anti-inflammatory drugs and the risk of head and neck cancer: A case-control analysis

Non-steroidal anti-inflammatory drugs (NSAIDs) and acetylsalicylic acid (aspirin) have been associated with a reduced risk for certain cancers. We explored the association between use of NSAIDs and the risk of head and neck cancer (HNC). We conducted a case-control analysis in the UK-based Clinical Practice Research Datalink (CPRD) among people below the age of 90 years with incident HNC between 1995 and 2013. Six controls per case were matched on age, sex, calendar time, general practice, and number of years of active history in the CPRD prior to the HNC diagnosis. Other potential confounders including comorbidities and comedication were also evaluated, and we adjusted our final analyses for BMI, smoking and alcohol consumption. Our analyses included 2,745 HNC cases and 16,470 controls. Aspirin or NSAID use overall did not significantly change the HNC risk. However, patients with six or more prescriptions for ibuprofen were at a statistically significantly reduced risk for HNC (adjusted OR 0.59, 95% CI 0.37-0.94). The HNC risk tended to decrease with increasing cumulative exposure to ibuprofen, and to be more pronounced for cancer of the larynx. To conclude, in this large population-based observational study we found a decreased risk for HNC associated with regular use of ibuprofen.

Hitting the Bull's-Eye in Metastatic Cancers-NSAIDs Elevate ROS in Mitochondria, Inducing Malignant Cell Death

Tumor metastases that impede the function of vital organs are a major cause of cancer related mortality. Mitochondrial oxidative stress induced by hypoxia, low nutrient levels, or other stresses, such as genotoxic events, act as key drivers of the malignant changes in primary tumors to enhance their progression to metastasis. Emerging evidence now indicates that mitochondrial modifications and mutations resulting from oxidative stress, and leading to OxPhos stimulation and/or enhanced reactive oxygen species (ROS) production, are essential for promoting and sustaining the highly metastatic phenotype. Moreover, the modified mitochondria in emerging or existing metastatic cancer cells, by their irreversible differences, provide opportunities for selectively targeting their mitochondrial functions with a one-two punch. The first blow would block their anti-oxidative defense, followed by the knockout blow—promoting production of excess ROS, capitulating the terminal stage—activation of the mitochondrial permeability transition pore (mPTP), specifically killing metastatic cancer cells or their precursors. This review links a wide area of research relevant to cellular mechanisms that affect mitochondria activity as a major source of ROS production driving the pro-oxidative state in metastatic cancer cells. Each of the important aspects affecting mitochondrial function are discussed including: hypoxia, HIFs and PGC1 induced metabolic changes, increased ROS production to induce a more pro-oxidative state with reduced antioxidant defenses. It then focuses on how the mitochondria, as a major source of ROS in metastatic cancer cells driving the pro-oxidative state of malignancy enables targeting drugs affecting many of these altered processes and why the NSAIDs are an excellent example of mitochondria-targeted agents that provide a one-two knockout activating the mPTP and their efficacy as selective anticancer metastasis drugs.

Synergistic mediation of tumor signaling pathways in hepatocellular carcinoma therapy via dual-drug-loaded pH-responsive electrospun fibrous scaffolds

A novel pH-sensitive electrospun composite PLLA fibrous scaffold was developed with long-term anti-cancer drug release and short-term anti-inflammation drug release for liver cancer therapy.

Increase in sialylation and branching in the mouse serum N-glycome correlates with inflammation and ovarian tumour progression

Ovarian cancer is the most lethal gynaecological cancer and is often diagnosed in late stage, often as the result of the unavailability of sufficiently sensitive biomarkers for early detection, tumour progression and tumour-associated inflammation. Glycosylation is the most common posttranslational modification of proteins; it is altered in cancer and therefore is a potential source of biomarkers. We investigated the quantitative and qualitative effects of anti-inflammatory (acetylsalicylic acid) and pro-inflammatory (thioglycolate and chlorite-oxidized oxyamylose) drugs on glycosylation in mouse cancer serum. A significant increase in sialylation and branching of glycans in mice treated with an inflammation-inducing compound was observed. Moreover, the increases in sialylation correlated with increased tumour sizes. Increases in sialylation and branching were consistent with increased expression of sialyltransferases and the branching enzyme MGAT5. Because the sialyltransferases are highly conserved among species, the described changes in the ovarian cancer mouse model are relevant to humans and serum N-glycome analysis for monitoring disease treatment and progression might be a useful biomarker.

Suppression of natural killer cells by sorafenib contributes to prometastatic effects in hepatocellular carcinoma

Sorafenib, a multi-tyrosine kinase inhibitor, is a standard treatment for advanced hepatocellular carcinoma (HCC). The present study was undertaken to determine whether the growth and metastasis of HCC were influenced in mice receiving sorafenib prior to implantation with tumors, and to investigate the in-vivo and in-vitro effect of sorafenib on natural killer (NK) cells. In sorafenib-pretreated BALB/c nu/nu mice and C57BL/6 mice, tumor growth was accelerated, mouse survival was decreased, and lung metastasis was increased. However, the depletion of NK1.1⁺ cells in C57BL/6 mice eliminated sorafenib-mediated pro-metastatic effects. Sorafenib significantly reduced the number of NK cells and inhibited reactivity of NK cells against tumor cells, in both tumor-bearing and tumor-free C57BL/6 mice. Sorafenib down-regulated the stimulatory receptor CD69 in NK cells of tumor-bearing mice, but not in tumor-free mice, and inhibited proliferation of NK92-MI cells, which is associated with the blocking of the PI3K/AKT pathway, and inhibited cytotoxicity of NK cells in response to tumor targets, which was due to impaired ERK phosphorylation. These results suggest immunotherapeutic approaches activating NK cells may enhance the therapeutic efficacy of sorafenib in HCC patients.

Effects of flavocoxid, a dual inhibitor of COX and 5-lipoxygenase enzymes, on benign prostatic hyperplasia

BACKGROUND AND PURPOSE

Inflammation plays a key role in the development of benign prostatic hyperplasia (BPH). Eicosanoids derived from the COX and 5-lipoxygenase (5-LOX) pathways are elevated in the enlarging prostate. Flavocoxid is a novel flavonoid-based 'dual inhibitor' of the COX and 5-LOX enzymes. This study evaluated the effects of flavocoxid in experimental BPH.

EXPERIMENTAL APPROACH

Rats were treated daily with testosterone propionate (3 mg·kg(-1)  s.c.) or its vehicle for 14 days to induce BPH. Animals receiving testosterone were randomized to receive vehicle (1 mL·kg(-1) , i.p.) or flavocoxid (20 mg·kg(-1) , i.p.) for 14 days. Histological changes, eicosanoid content and mRNA and protein levels for apoptosis-related proteins and growth factors were assayed in prostate tissue. The effects of flavocoxid were also tested on human prostate carcinoma PC3 cells.

KEY RESULTS

Flavocoxid reduced prostate weight and hyperplasia, blunted inducible expression of COX-2 and 5-LOX as well as the increased production of PGE(2) and leukotriene B(4) (LTB(4) ), enhanced pro-apoptotic Bax and caspase-9 and decreased the anti-apoptotic Bcl-2 mRNA. Flavocoxid also reduced EGF and VEGF expression. In PC3 cells, flavocoxid stimulated apoptosis and inhibited growth factor expression. Flavocoxid-mediated induction of apoptosis was inhibited by the pan-caspase inhibitor, Z-VAD-FMK, in PC3 cells, suggesting an essential role of caspases in flavocoxid-mediated apoptosis during prostatic growth.

CONCLUSION AND IMPLICATIONS

Our results show that a 'dual inhibitor' of the COX and 5-LOX enzymes, such as flavocoxid, might represent a rational approach to reduce BPH through modulation of eicosanoid production and a caspase-induced apoptotic mechanism.

Crystal structures of three classes of non-steroidal anti-inflammatory drugs in complex with aldo-keto reductase 1C3

Aldo-keto reductase 1C3 (AKR1C3) catalyses the NADPH dependent reduction of carbonyl groups in a number of important steroid and prostanoid molecules. The enzyme is also over-expressed in prostate and breast cancer and its expression is correlated with the aggressiveness of the disease. The steroid products of AKR1C3 catalysis are important in proliferative signalling of hormone-responsive cells, while the prostanoid products promote prostaglandin-dependent proliferative pathways. In these ways, AKR1C3 contributes to tumour development and maintenance, and suggest that inhibition of AKR1C3 activity is an attractive target for the development of new anti-cancer therapies. Non-steroidal anti-inflammatory drugs (NSAIDs) are one well-known class of compounds that inhibits AKR1C3, yet crystal structures have only been determined for this enzyme with flufenamic acid, indomethacin, and closely related analogues bound. While the flufenamic acid and indomethacin structures have been used to design novel inhibitors, they provide only limited coverage of the NSAIDs that inhibit AKR1C3 and that may be used for the development of new AKR1C3 targeted drugs. To understand how other NSAIDs bind to AKR1C3, we have determined ten crystal structures of AKR1C3 complexes that cover three different classes of NSAID, N-phenylanthranilic acids (meclofenamic acid, mefenamic acid), arylpropionic acids (flurbiprofen, ibuprofen, naproxen), and indomethacin analogues (indomethacin, sulindac, zomepirac). The N-phenylanthranilic and arylpropionic acids bind to common sites including the enzyme catalytic centre and a constitutive active site pocket, with the arylpropionic acids probing the constitutive pocket more effectively. By contrast, indomethacin and the indomethacin analogues sulindac and zomepirac, display three distinctly different binding modes that explain their relative inhibition of the AKR1C family members. This new data from ten crystal structures greatly broadens the base of structures available for future structure-guided drug discovery efforts.

Effects of cyclooxygenase inhibitors in combination with taxol on expression of cyclin D1 and Ki-67 in a xenograft model of ovarian carcinoma

The present study was designed to investigate the effects of cyclooxygenase (COX) inhibitors in combination with taxol on the expression of cyclin D1 and Ki-67 in human ovarian SKOV-3 carcinoma cells xenograft-bearing mice. The animals were treated with 100 mg/kg celecoxib (a COX-2 selective inhibitor) alone, 3 mg/kg SC-560 (a COX-1 selective inhibitor) alone by gavage twice a day, 20 mg/kg taxol alone by intraperitoneally (i.p.) once a week, or celecoxib/taxol, SC-560/celecoxib, SC-560/taxol or SC-560/celecoxib/taxol, for three weeks. To test the mechanism of the combination treatment, the index of cell proliferation and expression of cyclin D1 in tumor tissues were determined by immunohistochemistry. The mean tumor volume in the treated groups was significantly lower than control (p < 0.05), and in the three-drug combination group, tumor volume was reduced by 58.27% (p < 0.01); downregulated cell proliferation and cyclin D1 expression were statistically significant compared with those of the control group (both p < 0.01). This study suggests that the effects of COX selective inhibitors on the growth of tumors and decreased cell proliferation in a SKOV-3 cells mouse xenograft model were similar to taxol. The three-drug combination showing a better decreasing tendency in growth-inhibitory effect during the experiment may have been caused by suppressing cyclin D1 expression.

Novel NSAID 1-acyl-4-cycloalkyl/arylsemicarbazides and 1-acyl-5-benzyloxy/hydroxy carbamoylcarbazides as potential anticancer agents and antioxidants

The novel 1-acyl-4-cycloalkyl/arylsemicarbazides (5a-y) and 1-acyl-5-benzyloxy/hydroxycarbamoylcarbazides (8a-f) derived from the nonsteroidal anti-inflammatory drugs ibuprofen, fenoprofen and reduced ketoprofen were prepared, fully chemically characterized and evaluated for their cytostatic, antiviral and antioxidant activities. Compounds 5 and 8 consist of a region rich in electronegative atoms (five to nine nitrogen and oxygen atoms) framed by aryl or cycloalkyl residues on one or both terminal ends. The synthetic pathways applied for the preparation of the title compounds involved a benzotriazole as a synthetic auxiliary in several steps. Three of the tested compounds, namely 4-benzhydryl-1-[2-(3-phenoxyphenyl)propanoyl]semicarbazide (5l), 4-benzhydryl-1-[2-(3-benzylphenyl)propanoyl]semicarbazide (5s), and 4-benzhydryl-1-[2-(4-isobutylphenyl)propanoyl]semicarbazide (5f) showed pronounced antiproliferative activity in vitro against six cancer cell lines (IC(50)=3-23 μM). The same compounds highly inhibited soybean lipoxygenase (IC(50)=60 and 51.5 μM) and lipid peroxidation as well (99, 88 and 74%, respectively). 4-Benzyloxy-1-[2-(4-isobutylphenyl)propanoyl]semicarbazide (5t) and 5-benzyloxycarbamoyl-1-[2-(3-benzylphenyl)propanoyl]carbazide (8c) exerted complete lipid peroxidation inhibition. Semicarbazides 5w-y and carbazides 8d-f bearing a hydroxamic acid/hydroxyurea moiety showed a modest antiradical activity in DPPH test, while the best radical scavenger was 1-(1-benzotriazolecarbonyl)-4-benzyloxysemicarbazide (7). None of the compounds were inhibitory to a broad panel of DNA and RNA viruses in the cell culture at subtoxic concentrations.

Synergistic cytotoxic effect of sulindac and pyrrolidine dithiocarbamate against ovarian cancer cells

Sulindac, a non-steroidal anti-inflammatory drug, suppresses carcinogenesis and inhibits growth of tumor cells. Pyrrolidine dithiocarbamate (PDTC), a potent NF-κB inhibitor, has been also identified as a potential anti-neoplastic agent. We hypothesized that combination of sulindac and PDTC could result in augmentation of cytotoxicity against ovarian cancer cells. The effect of sulindac and PDTC was examined on several ovarian cancer lines. Tumor cell viability was assessed using the MTT assay. Annexin-V/PI staining was used to detect apoptosis, cell cycle distribution was analyzed in FACS, and expression of cellular proteins was detected by Western blotting. Incubation of OVA-14, OVP-10 and CAOV-1 ovarian cancer cells with sulindac and PDTC resulted in significantly greater inhibition of cell viability compared to either compound alone. In a model of OVA-14 cells it was evident that this effect was not related to the expression of COX enzymes since both active (sulindac sulfide) and inactive (sulindac) in vitro compounds affected the growth of tumor cells to a similar extent and synergized in cytotoxicity with PDTC. Combination of sulindac and PDTC lead to G0 arrest and massive apoptosis in co-treated cultures. Western blotting analysis argued for induction of the mitochondrial apoptotic pathway. These data demonstrate the synergistic cytotoxic effect of sulindac and PDTC on ovarian cancer cells through apoptosis and cell cycle arrest and prompt to test the efficacy of this combination in animal models.

The target of arachidonic acid pathway is a new anticancer strategy for human prostate cancer

Recent epidemiological studies and animal experiments have demonstrated that nonsteroidal anti-inflammatory drugs (NSAIDs) reduce the incidence of colorectal carcinoma. Cyclooxygenase (COX) is the principal target of NSAIDs. COX is the first oxidase in the process of prostaglandin production from arachidonic acid. COX enzyme may be involved in the initiation and/or the promotion of carcinogenesis due to NSAIDs inhibition of COX. Lipoxygenase (LOX) is also an initial enzyme in the pathway for producing leukotrienes from arachidonic acid. Similar to COX, LOX enzyme may also be involved in the initiation and/or promotion of carcinogenesis. Peroxisome proliferator activator-receptor (PPAR)-γ is a ligand-activated transcriptional factor belonging to the steroid receptor superfamily. PPAR-γ plays a role in both adipocyte differentiation and carcinogenesis. PPAR-γ is one target for cell growth modulation of NSAIDs. In this review, we report the expression of COX-2, LOX and PPAR-γ in human prostate cancer tissues as well as the effects of COX-2 and LOX inhibitors and PPAR-γ ligand.

Evaluation of indomethacin and dexamethasone effects on BCRP-mediated drug resistance in MCF-7 parental and resistant cell lines

Breast cancer resistance protein is a member of the ATP-binding cassette transporter G family that extrudes xenotoxins from cells, mediating drug resistance, and has been recognized as a major cause of failure of various carcinoma chemotherapies. In this study, the modulatory effects of dexamethasone and indomethacin on the cell cytotoxicity of mitoxantrone and on the BCRP protein activity in breast cancer cell lines were examined. MCF cells were seeded at 1 x 10(4) cells per well in 96-well flat-bottomed microplates for 48 hours and treated with increasing doses of dexamethasone, indomethacin, and novobiocin alone or preincubated with increasing doses of the drugs and then coexposed to mitoxantrone. Cell viability was measured after 1-4 days, using the MTT assay. BCRP activity was determined flow cytometrically by measuring mitoxantrone accumulation in the absence and presence of the inhibitor, novobiocin. Cotreatment of mitoxantrone with different concentrations of dexamethasone and indomethacin sensitized parental and resistant MCF-7 cells to mitoxantrone cytotoxicity. Dexamethasone increased the accumulation of mitoxantrone in the MCF-7/MX cell line, indicating an inhibition of BCRP. In spite of increased levels of mitoxantrone cytotoxicity in the presence of indomethacin, the accumulation of mitoxantrone was not increased in indomethacin-treated MCF cells.

Celecoxib enhances the inhibitory effect of cisplatin on Tca8113 cells in human tongue squamous cell carcinoma in vivo and in vitro

BACKGROUND

Overexpression of cyclooxygenase-2 (COX-2) is associated with carcinogenesis, invasiveness, and metastasis of malignant tumors. Inhibition of COX-2 is one hot topic of research in prevention and treatment of malignant tumors. Because of the selective and specific inhibition on the activity of COX-2, the roles of celecoxib in prevention and treatment of tumors have attracted broad attention in recent years. In this study, we investigated the inhibitory effect of celecoxib combined with cisplatin on the proliferation of human tongue squamous cell carcinoma cell line Tca8113 in vivo and in vitro.

METHODS

Human tongue squamous cell carcinoma tumor cells Tca8113 and a mouse model with Tca8113 cells were used to study the growth inhibition of cisplatin enhanced by celecoxib. Drug treatment of Tca8113 in vitro and mice bearing xenografts in vivo were used. The level of COX-2 expression was detected by Western blotting. Sensitivity of cells to drug treatment was analyzed by MTT assay.

RESULTS

Treatment of Tca8113 cells with cisplatin (CDDP) had less effect on the expression of COX-2, whereas the COX-2 expression was significantly down-regulated after treatment with celecoxib alone or in combination with CDDP for 24 h. In addition, the combination of celecoxib with CDDP was also able to inhibit the Tca8113 line heterotransplanted in Balb/c nude mice.

CONCLUSIONS

Those findings indicate that a low dose of celecoxib could augment CDDP-induced growth inhibition of Tca8113 cells and its xenograft in Balb/c nude mice.

Rofecoxib augments anticancer effects by reversing intrinsic multidrug resistance gene expression in BGC-823 gastric cancer cells

OBJECTIVE

To investigate combined chemotherapeutic effects of rofecoxib in combination with 5-fluorouracil (5-FU), cisplatin (DDP) and etoposide (VP-16) in vitro, and to explore the potential mechanisms in modulating multidrug resistance (MDR) expression.

METHODS

The BGC-823 gastric cancer cell line was incubated for 48 h with 0.1 micromol/L rofecoxib, 5-FU, DDP and VP-16 (1 microg/mL, 10 microg/mL and 100 microg/mL) alone, and combined with rofecoxib, respectively. Methyl-thiazolyl-tetrazolium and the terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-yriphosphate nick-end labeling assays were performed to calculate inhibitory rates and apoptotic index. Middle effects principles (CI values) were used to determine the interaction between rofecoxib and chemotherapeutic agents. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis were employed to determine expression of MDR1, multidrug resistance-associated protein 1 (MRP1), glutathione S-tranferase-pi (GST-pi) mRNA and protein in gastric cancer cells administered by rofecoxib, respectively.

RESULTS

Both anticancer drugs such as 5-FU, DDP and VP-16 and rofecoxib inhibited the cells' proliferation and induced apoptosis in a dose-dependent manner, and a more significant inhibition was achieved when the cells were co-treated with anticancer drugs and rofecoxib. There was a synergetic role when different concentrations of chemotherapeutic agents were combined with rofecoxib (all CI < 1, P < 0.01 or 0.05). RT-PCR analyses of MDR gene families in BGC-823 gastric cancer cells revealed a strong expression in MRP1 and GST-pi mRNA, but MDR1 mRNA was undetectable. After administration with different concentrations of rofecoxib (0.1, 1.0, 10 micromol/L), significant downregulation of MRP1 and GST-pi mRNA was observed (MRP1: from 0.984 +/- 0.093-0.513 +/- 0.098; GST-pi: from 1.078 +/- 0.201-0.472 +/- 0.084, P < 0.01 or 0.05). In addition, MRP1 and GST-pi protein expression induced by rofecoxib were also reduced (P < 0.01 or 0.05).

CONCLUSION

Rofecoxib, a specific cyclooxygenase-2 inhibitor, plays a chemotherapeutic sensitizer role in various anticancer agents on the BGC-823 gastric cancer cell line, which could be partly explained by its ability to reverse the intrinsic MRP1 and GST-piin vitro.

15-Hydroxyprostaglandin dehydrogenase (15-PGDH) is up-regulated by flurbiprofen and other non-steroidal anti-inflammatory drugs in human colon cancer HT29 cells

Non-steroidal anti-inflammatory drugs (NSAIDs) are known to inhibit prostaglandin synthetic enzyme, cyclooxygenases (COXs), as well as to exhibit anti-tumor activity although at much higher concentrations. 15-Hydroxyprostaglandin dehyrogenase (15-PGDH), a key prostaglandin catabolic enzyme, was recently shown to be a tumor suppressor. Effects of NSAIDs on 15-PGDH expression were therefore examined. Flurbiprofen and several other NSAIDs were found to induce 15-PGDH expression in human colon cancer HT29 cells. Flurbiprofen, the most active one, was also shown to induce 15-PGDH expression in other types of cancer cells. Induction of 15-PGDH expression appeared to occur at the stage of mRNA as levels of 15-PGDH mRNA were increased by flurbiprofen in HT29 cells. Levels of 15-PGDH were also found to be regulated at the stage of protein turnover. MEK inhibitors, PD98059 and U-0126, which inhibited ERK phosphorylation were shown to elevate 15-PGDH levels very significantly. These inhibitors did not appear to alter 15-PGDH mRNA levels but down-regulate matrix metalloproteinase-9 (MMP-9). This protease was shown to degrade and inactivate 15-PGDH suggesting that elevation of 15-PGDH levels could be due to inhibition of MMP-9 expression by these inhibitors. Similarly, flurbiprofen was also demonstrated to inhibit ERK activation and to down-regulate MMP-9 expression. Furthermore, flurbiprofen was shown to induce the expression of tissue inhibitor of metalloproteinase-1 (TIMP-1), an inhibitor of MMP-9. The turnover of 15-PGDH was found to prolong in the presence of flurbiprofen as compared to that in the absence of this drug. Taken together, these results indicate that flurbiprofen up-regulates 15-PGDH by increasing the expression and decreasing the degradation of 15-PGDH in HT29 cells.

Dietary aspirin decreases the stage of ovarian cancer in the hen

OBJECTIVE

We aimed to determine the effects of dietary aspirin treatment on ovarian cancer incidence and progression in the hen as a model for the human disease.

METHODS

Hens were fed a standard layer diet (control) or the same diet containing 0.1% aspirin for 1 year. Liver prostaglandin E(2) (PGE(2)) was measured using an enzyme immunoassay. Incidence and stage of ovarian cancer were determined through necropsy and immunohistochemical analysis of ovarian sections for each hen.

RESULTS

Aspirin treatment decreased liver PGE(2) in treated hens as compared to control hens. Treatment with aspirin did not decrease ovarian cancer incidence. Significantly more control hens developed late stage ovarian cancer than early stage, while the same was not true for aspirin-treated hens. Hens that developed ovarian cancer, even early ovarian cancer, produced significantly fewer eggs in the year prior to diagnosis than hens without ovarian cancer.

CONCLUSIONS

Aspirin treatment may inhibit the progression of ovarian cancer in the hen and egg production may be used to identify hens with early stages of the disease.