COX-2 inhibitors and other nonsteroidal anti-inflammatory drugs in genitourinary cancer

Immunohistochemical Expression Levels of Epidermal Growth Factor Receptor, Cyclooxygenase-2, and Ki-67 in Canine Cutaneous Squamous Cell Carcinomas

Squamous cell carcinoma (SCC) stands as the second most prevalent skin cancer in dogs, primarily attributed to UV radiation exposure. Affected areas typically include regions with sparse hair and pale or depigmented skin. The significance of spontaneous canine cutaneous SCC as a model for its human counterpart is underscored by its resemblance. This study assesses the expression of key markers-Epidermal Growth Factor Receptor (EGFR), Cyclooxygenase-2 (Cox-2), and Ki-67-in canine cutaneous SCC. Our objective is to investigate the association between their expression levels and classical clinicopathological parameters, unraveling the intricate relationships among these molecular markers. In our retrospective analysis of 37 cases, EGFR overexpression manifested in 43.2% of cases, while Cox-2 exhibited overexpression in 97.3%. The EGFR, Cox-2 overexpression, and Ki-67 proliferation indices, estimated through immunohistochemistry, displayed a significant association with the histological grade, but only EGFR labeling is associated with the presence of lymphovascular emboli. The Ki-67 labeling index expression exhibited an association with EGFR and Cox-2. These findings propose that EGFR, Cox-2, and Ki-67 hold promise as valuable markers in canine SCC. EGFR, Cox-2, and Ki-67 may serve as indicators of disease progression, offering insights into the malignancy of a lesion. The implications extend to the potential therapeutic targeting of EGFR and Cox-2 in managing canine SCC. Further exploration of these insights is warranted due to their translational relevance and the development of targeted interventions in the context of canine SCC.

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.

Targeting the mercapturic acid pathway and vicenin-2 for prevention of prostate cancer

Prostate cancer (CaP) is often androgen-sensitive malignancy and regresses upon inhibition of androgen signaling. However, CaP, nearly always develops androgen resistance and progresses to aggressive and lethal androgen-independent CaP, which lacks satisfactory therapy. For metastatic CaP, patients are often treated with Taxotere (docetaxel), a cytoskeleton-targeted chemotherapy drug, that provides transient palliative benefit but to which patients rapidly develop drug-resistance. Combination chemotherapy may be used instead, but is more toxic and adds little clinically relevant benefit over docetaxel. Therefore, novel strategies to enhance docetaxel efficacy are needed to effectively treat patients with metastatic CaP. The mercapturic acid pathway, which metabolizes genotoxic and pro-apoptotic toxins, is over-expressed in CaP and plays an important role in carcinogenesis, metastasis and therapy-resistance of CaP. Vicenin-2, a flavonoid derived from Tulsi (holy basil) as an active compound, inhibits the growth of CaP and increases the anti-tumor activity of docetaxel in-vitro and in-vivo. Taken together, the combination of vicenin-2 and docetaxel could be highly effective in the treatment of advanced and metastatic CaP due to their multi-targeting anti-tumor potential.

Low-dose aspirin or other nonsteroidal anti-inflammatory drug use and prostate cancer risk: a nationwide study

PURPOSE

Increasing evidence suggests that aspirin use may protect against prostate cancer. In a nationwide case-control study, using Danish high-quality registry data, we evaluated the association between the use of low-dose aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs) and the risk of prostate cancer.

METHODS

We identified 35,600 patients (cases) with histologically verified prostate cancer during 2000-2012. Cases were matched to 177,992 population controls on age and residence by risk-set sampling. Aspirin and nonaspirin NSAID exposure was defined by type, estimated dose, duration, and consistency of use. We used conditional logistic regression to estimate odds ratios (ORs), with 95 % confidence intervals (CIs), for prostate cancer associated with low-dose aspirin (75-150 mg) or nonaspirin NSAID use, adjusted for potential confounders.

RESULTS

Use of low-dose aspirin was associated with an OR for prostate cancer of 0.94 (95 % CI 0.91-0.97). Slightly lower ORs were seen with increasing cumulative amount, duration, and consistency of low-dose aspirin use (continuous use, ≥5 years: OR 0.89; 95 % CI 0.82-0.97; ≥10 years: OR 0.86; 95 % CI 0.70-1.06). Nonaspirin NSAID use was associated with a slightly increased OR for prostate cancer (1.13; 95 % CI 1.10-1.15); however, this association was confined to localized disease and did not vary materially with amount, duration, or consistency of nonaspirin NSAID use.

CONCLUSIONS

Our study indicates that long-term, consistent low-dose aspirin use may provide modest protection against prostate cancer. The slightly increased risk of only localized prostate cancer with nonaspirin NSAID use suggests a noncausal explanation of the observed association.

Can daily intake of aspirin and/or statins influence the behavior of non-muscle invasive bladder cancer? A retrospective study on a cohort of patients undergoing transurethral bladder resection

Background

This study aimed to evaluate the behavior of non-muscle-invasive bladder cancer (NMIBC) in patients submitted to transurethral bladder resection (TURB) comparing subjects in chronic therapy with aspirin, statins, or both drugs to untreated ones.

Methods

This retrospective study was conducted on 574 patients diagnosed with NMIBC who underwent TURB between March 2008 and April 2013. The study population was divided into two main groups: treated (aspirin and/or statins) and untreated. The treated group was further divided into three therapeutic subgroups: Group A (100 mg of aspirin, daily for at least two years); Group B (20 mg or more of statins, daily for at least two years); and Group C (100 mg of aspirin and 20 mg of statins together). The mean follow-up of patients was 45.06 months.

Results

No significant differences were observed among the different groups at baseline. On multivariate analysis, statin treatment, smokers and high stage disease (T1) achieved the level of independent risk factor for the occurrence of a recurrence. When patients were stratified according to the different treatment; patients treated with statins (Group B) presented an higher rate of failure (56/91 patients; 61.5%) when compared to Group A (42/98 patients; 42.9%), Group C (56/98; 57.1%) and (133/287 patients; 46.3%). This difference corresponds to a significant difference in recurrence failure free survival (p = 0.01).

Conclusions

Our results suggest that long-term treatment with aspirin in patients with NMIBC might play a role on reducing the risk of tumor recurrence. In contrast, in our investigation data from statins and combination treatment groups showed increased recurrence rates. A long-term randomized prospective study could definitively assess the possible role of this widely used drugs in NMIBC.

Aspirin, NSAIDs, and risk of prostate cancer: results from the REDUCE study

PURPOSE

A recent meta-analysis showed that aspirin was associated with reduced prostate cancer risk. As anti-inflammatory medications lower PSA levels, whether these findings reflect reduced prostate cancer detection or lower prostate cancer risk is unknown. We tested the association between aspirin and nonaspirin NSAID use on prostate cancer diagnosis in REDUCE, where all men received biopsies at 2 and 4 years largely independent of PSA. REDUCE tested dutasteride for prostate cancer risk reduction in men with a PSA of 2.5 to 10.0 ng/mL and a negative prestudy biopsy.

EXPERIMENTAL DESIGN

We examined the association between aspirin, NSAIDs, or both and total, low-grade (Gleason < 7), or high-grade (Gleason ≥ 7) prostate cancer versus no prostate cancer using multinomial logistic regression among 6,390 men who underwent ≥1 on-study biopsy. Multivariable analyses were adjusted for age, race, geographic region, PSA, prostate volume, digital rectal examination, body mass index, treatment arm, smoking, alcohol, statins, hypertension, diabetes, and cardiovascular disease.

RESULTS

Overall, 3,169 men (50%) were nonusers, 1,368 (21%) used aspirin, 1,176 (18%) used NSAIDs, and 677 (11%) used both. In unadjusted models, aspirin was associated with reduced prostate cancer risk (OR = 0.85, P = 0.036). In multivariable analyses, aspirin was associated with reduced total prostate cancer risk (OR = 0.81, P = 0.015). Use of NSAIDs or NSAIDs and aspirin was not associated with total, low-grade, or high-grade prostate cancer, though all ORs were <1 (all P ≥ 0.08). Therefore, we created a dichotomous variable of aspirin and/or NSAID users versus nonusers. On multivariable analysis, the use of aspirin and/or NSAIDs was significantly associated with decreased total (OR = 0.87, P = 0.030) and high-grade (OR = 0.80, P = 0.040), but not with low-grade, prostate cancer risk (OR = 0.90, P = 0.15). Results were similar in placebo and dutasteride arms.

CONCLUSIONS

Among men with a negative biopsy, aspirin and/or NSAID use was associated with decreased prostate cancer risk. Additional studies are warranted.

Meta-analysis of nonsteroidal anti-inflammatory drug intake and prostate cancer risk

BACKGROUND

Epidemiological studies of the association between nonsteroidal anti-inflammatory drug (NSAID) intake and the risk of prostate cancer still remain controversial. Therefore, we conducted a meta-analysis to evaluate the potential association between NSAID intake and prostate cancer risk.

METHODS

Eligible studies were retrieved by both computerized searches and reviews of references. Subgroup analyses on country and design of study were also performed. Random or fixed-effect models were used to pool estimates of odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

We observed that the intake of aspirin was associated with a marginally decreased risk of prostate cancer (OR = 0.95, 95% CI = 0.93 to 0.98). A similar result was found between nonaspirin NSAIDs and prostate cancer risk (OR = 0.94, 95% CI =0.90 to 0.98). However, a positive relation between all-NSAID intake and prostate cancer risk was observed (OR = 1.18, 95% CI = 1.15 to 1.22).

CONCLUSIONS

We observed a marginally inverse correlation between the intake of aspirin and prostate cancer risk. On the contrary, a positive relationship between all-NSAID intake and prostate cancer was detected. Further research needs to be conducted to better clarify potential biological mechanisms.

Aspirin use and the risk of prostate cancer: a meta-analysis of 24 epidemiologic studies

PURPOSE

Several epidemiologic studies were performed to clarify the protective effect of regular aspirin use on prostate cancer risk; however, the results remain controversial. Therefore, we conducted this meta-analysis to assess the association between regular aspirin use and risk of prostate cancer.

METHODS

Electronic databases including PubMed, EMBASE and Cochrane Library were searched between January 1966 and April 2013 to identify eligible studies. Pooled relative ratios (RRs) and 95 % confidence intervals (CIs) were computed to assess the influence of aspirin use on prostate cancer risk. All statistical tests were two-sided.

RESULTS

A total of 24 observational studies including 14 case-control studies and 10 cohort studies were eligible for this meta-analysis. Regular aspirin use was associated with reduction in overall and advanced prostate cancer risk (pooled RR 0.86, 95 % CI 0.81-0.92; pooled RR 0.83, 95 % CI 0.75-0.91, respectively). When we restricted our analyses to studies with long-time regular aspirin use (equal or more than 4 years), reverse association became stronger (pooled RR 0.82, 95 % CI 0.72-0.93; pooled RR 0.70, 95 % CI 0.55-0.90, respectively).

CONCLUSIONS

Our findings suggest that regular, especially long-time regular aspirin use may reduce the risk of overall and advanced prostate cancer. Considering the limitation of included studies, further well-designed large-scaled cohort studies and RCTs are required to draw more definitive conclusions.

A randomized controlled trial of celecoxib to prevent recurrence of nonmuscle-invasive bladder cancer

Significant morbidity and expense result from frequent recurrences of nonmuscle-invasive bladder cancer (NMIBC) after standard treatment, and carcinoma in situ (Tis) is a poor prognostic factor. Predicated on observational and preclinical data strongly supporting cyclooxygenase-2 (COX-2) in the pathogenesis, and the activity of COX-2 inhibitors, in bladder cancer, we conducted a randomized, double-blind, placebo-controlled trial to determine whether celecoxib could reduce the time-to-recurrence (TTR) in NMIBC patients at high risk for recurrence. A total of 146 patients were randomized to celecoxib (200 mg) or placebo orally twice daily for at least 12 months. The average treatment duration was 1.25 years. Primary intent-to-treat analysis revealed celecoxib did not statistically significantly prolong TTR compared with placebo (P = 0.17, log rank) with a median follow-up of 2.49 years. The recurrence-free rate at 12 months with celecoxib was 88% (95% CI: 0.81-0.96) versus 78% (95% CI: 0.69-0.89) with placebo. After controlling for covariates with Cox regression analysis, recurrence rates did not differ between the two study arms (HR = 0.69; 95% CI: 0.37-1.29). However, celecoxib had a marginally significant effect on reducing metachronous recurrences (vs. placebo) with HR of 0.56 (95% CI: 0.3-1.06; P = 0.075). Celecoxib was well tolerated, with similar adverse events and quality-of-life in both arms. Our clinical trial results do not show a clinical benefit for celecoxib in preventing NMIBC recurrence but further investigation of COX-2 inhibitors in this setting is warranted.

Anti-cancer effects of novel flavonoid vicenin-2 as a single agent and in synergistic combination with docetaxel in prostate cancer

The present study was conducted to determine the efficacy of novel flavonoid vicenin-2 (VCN-2), an active constituent of the medicinal herb Ocimum Sanctum Linn or Tulsi, as a single agent and in combination with docetaxel (DTL) in carcinoma of prostate (CaP). VCN-2 effectively induced anti-proliferative, anti-angiogenic and pro-apoptotic effect in CaP cells (PC-3, DU-145 and LNCaP) irrespective of their androgen responsiveness or p53 status. VCN-2 inhibited EGFR/Akt/mTOR/p70S6K pathway along with decreasing c-Myc, cyclin D1, cyclin B1, CDK4, PCNA and hTERT in vitro. VCN-2 reached a level of 2.6±0.3μmol/l in serum after oral administration in mice which reflected that VCN-2 is orally absorbed. The i.v. administration of docetaxel (DTL), current drug of choice in androgen-independent CaP, is associated with dose-limiting toxicities like febrile neutropenia which has lead to characterization of alternate routes of administration and potential combinatorial regimens. In this regard, VCN-2 in combination with DTL synergistically inhibited the growth of prostate tumors in vivo with a greater decrease in the levels of AR, pIGF1R, pAkt, PCNA, cyclin D1, Ki67, CD31, and increase in E-cadherin. VCN-2 has been investigated for radioprotection and anti-inflammatory properties. This is the first study on the anti-cancer effects of VCN-2. In conclusion, our investigations collectively provide strong evidence that VCN-2 is effective against CaP progression along with indicating that VCN-2 and DTL co-administration is more effective than either of the single agents in androgen-independent prostate cancer.

Nanoprodrugs of NSAIDs: Preparation and Characterization of Flufenamic Acid Nanoprodrugs

We demonstrated that hydrophobic derivatives of the nonsteroidal anti-inflammatory drug (NSAID)flufenamic acid (FA), can be formed into stable nanometer-sized prodrugs (nanoprodrugs) that inhibit the growth of glioma cells, suggesting their potential application as anticancer agent. We synthesized highly hydrophobic monomeric and dimeric prodrugs of FA via esterification and prepared nanoprodrugs using spontaneous emulsification mechanism. The nanoprodrugs were in the size range of 120 to 140 nm and physicochemically stable upon long-term storage as aqueous suspension, which is attributed to the strong hydrophobic interaction between prodrug molecules. Importantly, despite the highly hydrophobic nature and water insolubility, nanoprodrugs could be readily activated into the parent drug by porcine liver esterase, presenting a potential new strategy for novel NSAID prodrug design. The nanoprodrug inhibited the growth of U87-MG glioma cells with IC₅₀ of 20 μM, whereas FA showed IC₅₀ of 100 μM, suggesting that more efficient drug delivery was achieved with nanoprodrugs.

Use of non-steroidal anti-inflammatory drugs and prostate cancer risk: a population-based nested case-control study

Background

Despite strong laboratory evidence that non-steroidal anti-inflammatory drugs (NSAIDs) could prevent prostate cancer, epidemiological studies have so far reported conflicting results. Most studies were limited by lack of information on dosage and duration of use of the different classes of NSAIDs.

Methods

We conducted a nested case-control study using data from Saskatchewan Prescription Drug Plan (SPDP) and Cancer Registry to examine the effects of dose and duration of use of five classes of NSAIDs on prostate cancer risk. Cases (N = 9,007) were men aged ≥40 years diagnosed with prostatic carcinoma between 1985 and 2000, and were matched to four controls on age and duration of SPDP membership. Detailed histories of exposure to prescription NSAIDs and other drugs were obtained from the SPDP.

Results

Any use of propionates (e.g., ibuprofen, naproxen) was associated with a modest reduction in prostate cancer risk (Odds ratio = 0.90; 95%CI 0.84-0.95), whereas use of other NSAIDs was not. In particular, we did not observe the hypothesized inverse association with aspirin use (1.01; 0.95–1.07). There was no clear evidence of dose-response or duration-response relationships for any of the examined NSAID classes.

Conclusions

Our findings suggest modest benefits of at least some NSAIDs in reducing prostate cancer risk.

Use of nonsteroidal anti-inflammatory drugs and prostate cancer risk: a meta-analysis

The association between use of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) and the risk of prostate cancer remains controversial despite many observational epidemiological studies. We conducted a systematic meta-analysis of these studies to examine both the strength and the consistency of the association, and to explore sources of variability between studies. We searched 12 computerized literature databases for reports published before June 2008 and included any epidemiologic studies where the outcome was prostate cancer incidence or mortality, and the exposure was use of NSAIDs. Studies that met the inclusion criteria comprised 10 case-control and 14 cohort studies with a total of 24,230 prostate cancer cases. Studies that assessed the effect of aspirin use on total prostate cancer had a pooled odds ratio (POR) of 0.83 (95%CI: 0.77-0.89), whereas those that assessed the effect of aspirin on advanced prostate cancer had a POR of 0.81 (0.72-0.92). Studies that examined the effects of non-aspirin NSAIDs or all NSAIDs were less consistent but still suggestive of reduced risks. However, most reviewed studies were limited by exposure and disease misclassification, by inadequate information on dose and duration of use and by the possibility of screening and other biases. In conclusion, the epidemiologic evidence for a protective effect of aspirin and other NSAID use against prostate cancer is suggestive but not conclusive. There is a need for well-designed observational studies with adequate exposure measurements, accurate case definition, attention to latency effects, and careful adjustment for screening and other biases.

Chemopreventive efficacy of naproxen and nitric oxide-naproxen in rodent models of colon, urinary bladder, and mammary cancers

Nonsteroidal anti-inflammatory drugs (NSAID) have been highly effective in preventing colon, urinary bladder, and skin cancer preclinically, and also in clinical trials of colon adenoma formation. However, certain NSAIDs cause gastrointestinal ulceration and may increase cardiovascular events. Naproxen seems to cause the lowest cardiovascular events of the common NSAIDs other than aspirin. Nitric oxide (NO)-naproxen was tested based on the finding that adding a NO group to NSAIDs may help alleviate GI toxicity. In the azoxymethane-induced rat colon aberrant crypt foci (ACF) model, naproxen administered at 200 and 400 ppm in the diet reduced mean ACFs in the colon by about 45% to 60%, respectively. NO-naproxen was likewise administered in the diet at roughly equimolar doses (300 and 600 ppm) and reduced total ACF by 20% to 40%, respectively. In the hydroxybutyl (butyl) nitrosamine rat urinary bladder cancer model, NO-naproxen was given at 183 or 550 ppm in the diet, and naproxen at 128 ppm. The NO-naproxen groups had 77% and 73% decreases, respectively, in the development of large urinary bladder tumors, whereas the 128 ppm naproxen group also showed a strong decrease (69%). If treatments were started 3 months after hydroxybutyl (butyl) nitrosamine, NO-naproxen (550 ppm) and naproxen (400 ppm) were also highly effective (86-94% decreases). In the methylnitrosourea-induced mammary cancer model in rats, NO-naproxen and naproxen showed nonsignificant inhibitions (12% and 24%) at 550 and 400 ppm, respectively. These data show that both naproxen and NO-naproxen are effective agents against urinary bladder and colon, but not mammary, carcinogenesis.

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.

Glycogen synthase kinase 3beta regulates cell death induced by synthetic triterpenoids

The induction of programmed cell death in premalignant or malignant cancer cells by chemopreventive agents could be a valuable tool to control prostate cancer initiation and progression. In this work, we present evidence that the C-28 methyl ester of the synthetic oleanane triterpenoid 2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oic acid (CDDO-Me) induces cell death in androgen-responsive and unresponsive human prostate cancer cell lines at nanomolar and low micromolar concentrations. CDDO-Me induced caspase-3, caspase-8, and caspase-9 activation; poly(ADP-ribose) polymerase cleavage; internucleosomal DNA fragmentation; and loss of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction in PC3 and DU145 cells. However, caspase-3 and caspase-8 inhibition by Z-DEVD-fmk and Z-IETD-fmk, respectively, or general caspase inhibition by BOC-D-fmk or Z-VAD-fmk did not rescue loss of cell viability induced by CDDO-Me, suggesting the activation of additional caspase-independent mechanisms. Interestingly, CDDO-Me induced inactivating phosphorylation at Ser(9) of glycogen synthase kinase 3beta (GSK3beta), a multifunctional kinase that mediates essential events promoting prostate cancer development and acquisition of androgen independence. The GSK3 inhibitor lithium chloride and, more effectively, GSK3 gene silencing sensitized PC3 and DU145 prostate cancer cells to CDDO-Me cytotoxicity. These data suggest that modulation of GSK3beta activation is involved in the cell death pathway engaged by CDDO-Me in prostate cancer cells.

NCX 4040, an NO-donating acetylsalicylic acid derivative: efficacy and mechanisms of action in cancer cells

Non-steroidal anti-inflammatory drugs (NSAIDs) have repeatedly shown to be effective in tumor prevention, but important side-effects limit their wide clinical use. Nitric oxide-releasing derivatives (NO-NSAIDs) are a promising class of compounds synthesized by combining a classic NSAID molecule with an NO-releasing moiety to counteract side-effects. These new chemical entities exhibit a significantly higher activity and much lower toxicity with respect to the parental drug. In the present paper, we report the results obtained from in in vitro experimental systems aimed to evaluate the activity and mechanisms of action of the novel NO-releasing aspirin derivative, NCX 4040. The in vitro studies were carried out on a panel of human colon (LoVo, LoVo Dx, WiDr, LRWZ), bladder (HT1376, MCR), and pancreatic (Capan-2, MIA PaCa-2, T3M4) cancer cell lines. With regard to colon cancer, NCX 4040 activity was also investigated in vitro in combination with drugs currently used in clinical practice and was validated in vivo on tumor-bearing mice xenografted with the aforementioned colon cancer cell lines. The in vitro studies showed a high cytotoxic activity of NCX 4040 in all tumor histotypes and demonstrated the pivotal role of the NO component in drug activity. It was also observed that NCX 4040 exerts a pro-apoptotic activity via a mitochondria-dependent pathway. Moreover, the in vivo studies on xenografted mice further confirmed the antitumor efficacy and low toxicity of NCX 4040 in colon cancer and highlighted its role as sensitizing agent of oxaliplatin cytotoxicity.

Phase III prevention trial of fenretinide in patients with resected non-muscle-invasive bladder cancer

PURPOSE

The study aims to evaluate the efficacy and toxicity of fenretinide in preventing tumor recurrence in patients with transitional cell carcinoma (TCC) of the bladder.

EXPERIMENTAL DESIGN

We conducted a multicenter phase III, randomized, placebo-controlled trial of fenretinide (200 mg/day orally for 12 months) in patients with non-muscle-invasive bladder TCC (stages Ta, Tis, or T1) after transurethral resection with or without adjuvant intravesical Bacillus Calmette-Guerin (BCG). Patients received cystoscopic evaluation and bladder cytology every 3 months during the 1-year on study drug and a final evaluation at 15 months. The primary endpoint was time to recurrence.

RESULTS

A total of 149 patients were enrolled; 137 were evaluable for recurrence. The risk of recurrence was considered to be "low" in 72% (no prior BCG) and intermediate or high in 32% (prior BCG) of the evaluable patients. Of the lower-risk group, 68% had solitary tumors and 32% had multifocal, low-grade papillary (Ta, grade 1 or grade 2) tumors. The 1-year recurrence rates by Kaplan-Meier estimate were 32.3% (placebo) versus 31.5% (fenretinide; P = 0.88 log-rank test). Fenretinide was well tolerated and had no unexpected toxic effects; only elevated serum triglyceride levels were significantly more frequent on fenretinide (versus placebo). The Data Safety and Monitoring Board recommended study closure at 149 patients (before reaching the accrual goal of 160 patients) because an interim review of the data showed a low likelihood of detecting a difference between the two arms, even if the original accrual goal was met.

CONCLUSIONS

Although well tolerated, fenretinide did not reduce the time-to-recurrence in patients with Ta, T1, or Tis TCC of the bladder.

Exisulind in combination with celecoxib modulates epidermal growth factor receptor, cyclooxygenase-2, and cyclin D1 against prostate carcinogenesis: in vivo evidence

PURPOSE

Nonsteroidal anti-inflammatory drugs mediate anticancer effects by modulating cyclooxygenase-2 (COX-2)-dependent and/or COX-2-independent mechanism(s); however, the toxicity issue is a concern with single agents at higher doses. In this study, we determined the combined effect of celecoxib, a COX-2 inhibitor, along with exisulind (sulindac sulfone/Aptosyn) at low doses in prostate cancer.

EXPERIMENTAL DESIGN

We used a sequential regimen of N-methyl-N-nitrosourea + testosterone to induce prostate cancer in Wistar-Unilever rats. Following carcinogen treatment, celecoxib and exisulind individually and their combination at low doses were given in NIH-07 diet for 52 weeks. We determined the incidence of prostatic intraepithelial neoplasia, adenocarcinomas, rate of tumor cell proliferation, and apoptosis. Immunohistochemical and Western blot analysis were done to determine COX-2, epidermal growth factor receptor (EGFR), Akt, androgen receptor, and cyclin D1 expression. Serum prostaglandin E2 and tumor necrosis factor-alpha levels were determined using enzyme immunoassay/ELISA assays.

RESULTS

The rats that received celecoxib in combination with exisulind at low doses showed a significant decrease in prostatic intraepithelial neoplasia and adenocarcinomas as well as an enhanced rate of apoptosis. An overall decrease in COX-2, EGFR, Akt, androgen receptor, and cyclin D1 expression was found associated with tumor growth inhibition. Reduced serum levels of COX-2 protein, prostaglandin E2, and tumor necrosis factor-alpha indicated anti-inflammatory effects. A strong inhibition of total and phosphorylated form of EGFR (Tyr(992) and Tyr(845)) and Akt (Ser(473)) was significant in rats given with these agents in combination.

CONCLUSIONS

In this study, we show for the first time that the combination of celecoxib with exisulind at low doses could prevent prostate carcinogenesis by altering key molecular events.

Expression of cyclooxygenase-2, P-glycoprotein and multi-drug resistance-associated protein in canine transitional cell carcinoma

Cyclooxygenase-2 (COX-2), P-glycoprotein (P-gp) and multi-drug resistance-associated protein (MRP) are considered important tumor-associated proteins in humans and dogs. In the present study, we immunohistochemically evaluated the expression of these proteins in canine patients with transitional cell carcinoma (TCC). Of 52 cases, 30 (57.7%) were positive for COX-2, 40 (76.9%) for P-gp, and only 10 (19.2%) for MRP. In addition, 27 samples (27/52, 51.9%) were positive for two markers, while 3 (5.7%) and 5 (9.6%) cases were positive and negative, respectively, for all three markers. No significant correlations were seen for COX-2 and P-gp on Fisher's exact test and Mann-Whitney's test, but a significance was seen on Spearman's rank correlation analysis using the IHC scoring system (P=0.043). These results suggest that P-gp expression is induced by overexpression of COX-2 in canine patients with TCC.

Tumor promotion as a target of cancer prevention

Tumor promotion is an essential process in multistage cancer development providing the conditions for clonal expansion and genetic instability of preneoplastic and premalignant cells. It is caused by a continuous disturbance of cellular signal transduction that results in an overstimulation of metabolic pathways along which mediators of cell proliferation and inflammation as well as genotoxic by-products are generated. Among such pathways the oxidative metabolism of arachidonic acid has turned out to be of utmost importance in tumor promotion. The aberrant overexpression of cyclooxygenase-2, an inducible enzyme of prostanoid synthesis and lipid peroxidation, is a characteristic feature of more than two-thirds of all human neoplasias, and the specific inhibition of this enzyme has been found to have a substantial chemopreventive effect in both animal models and man. The prostaglandins produced by COX-2 promote tumor development by stimulating cell proliferation and angiogenesis and by suppressing programmed cell death and immune defense. In mice, a COX-2 transgene fused with the keratin 5 promoter, which is constitutively active in the basal (proliferative) compartment of stratified and simple epithelia, causes a preneoplastic and premalignant phenotype in several organs. Among these organs, skin, mammary gland, urinary bladder, and pancreas have been investigated in more detail. Histologically and biochemically, the COX-2-dependent alterations resemble an autopromoted state that--as shown for skin and urinary bladder--strongly sensitizes the tissue for carcinogenesis. In transgenic animals COX-2 expression is not restricted to keratin 5-positive cells but is seen also in adjacent keratin 5-negative cells. This spreading of the COX-2 signal indicates a paracrine mechanism of autoamplification. While cancer chemoprevention by COX-2 inhibition is a rapidly developing field, much less is known about other pathways of unsaturated fatty acid metabolism, although some of them may play a role in carcinogenesis rivaling that of prostaglandin formation. Here an urgent demand for systematic research exists.

Combined inhibitory effects of green tea polyphenols and selective cyclooxygenase-2 inhibitors on the growth of human prostate cancer cells both in vitro and in vivo

PURPOSE

Cyclooxygenase-2 (COX-2) inhibitors hold promise for cancer chemoprevention; however, recent toxicity concerns suggest that new strategies are needed. One approach to overcome this limitation is to use lower doses of COX-2 inhibitors in combination with other established agents with complementary mechanisms. In this study, the effect of (-)epigallocatechin-3-gallate (EGCG), a promising chemopreventive agent from green tea, was tested alone and in combination with specific COX-2 inhibitors on the growth of human prostate cancer cells both in vitro and in vivo.

EXPERIMENTAL DESIGN

Human prostate cancer cells LNCaP, PC-3, and CWR22Rnu1 were treated with EGCG and NS398 alone and in combination, and their effect on growth and apoptosis was evaluated. In vivo, athymic nude mice implanted with androgen-sensitive CWR22Rnu1 cells were given green tea polyphenols (0.1% in drinking water) and celecoxib (5 mg/kg, i.p., daily, 5 days per week), alone and in combination, and their effect on tumor growth was evaluated.

RESULTS

Combination of EGCG (10-40 micromol/L) and NS-398 (10 micromol/L) resulted in enhanced (a) cell growth inhibition; (b) apoptosis induction; (c) expression of Bax, pro-caspase-6, and pro-caspase-9, and poly(ADP)ribose polymerase cleavage; (d) inhibition of peroxisome proliferator activated receptor gamma; and (e) inhibition of nuclear factor-kappaB compared with the additive effects of the two agents alone, suggesting a possible synergism. In vivo, combination treatment with green tea polyphenols and celecoxib resulted in enhanced (a) tumor growth inhibition, (b) lowering of prostate-specific antigen levels, (c) lowering of insulin-like growth factor-I levels, and (d) circulating levels of serum insulin-like growth factor binding protein-3 compared with results of single-agent treatment.

CONCLUSIONS

These data suggest synergistic and/or additive effects of combinatorial chemopreventive agents and underscore the need for rational design of human clinical trials.

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

PURPOSE

Previously, we reported in vitro observations suggesting that ibuprofen is an effective non-prescription non-steroidal anti-inflammatory drug (NSAID) to reduce the survival of human prostate cancer cells (Andrews et al. in Cancer Chemother Pharmacol 502:77-284, 2002), and that this observed effectiveness is mediated by an up-regulation of the p75 NTR tumor suppressor (Khwaja et al. in Cancer Res 646:207-6213, 2004). However, other NSAIDs and their derivatives have received significant attention with regard to their anti-cancer effectiveness and have been selected for clinical trials to treat a variety of human cancers. In this investigation, we compared celecoxib, sulindac sulfone, nitric oxide linked NSAIDs, and R-flurbiprofen with ibuprofen in their ability to inhibit the growth of a variety of human cancer cells lines including cells lines with multi-drug resistance. We also evaluated whether, like ibuprofen, an up-regulation of p75 NTR is a molecular mechanism that mediates the anti-growth effectiveness of these drugs.

MATERIALS AND METHODS

Selected dosages for each drug were evaluated for their ability to reduce the growth (MTT analysis) and induce apoptosis (Hoechst staining) of a variety of different cancer cell lines, including an ovarian cell line expressing multidrug resistance-1 glycoprotein (MDR-1). The drugs were then analyzed using immunoblot, RT-PCR and siRNA to study the role of p75 NTR in their anti-growth effectiveness.

RESULTS

Our study revealed consistency in the drug dosages that inhibit the survival of different human cancer cell lines. While NO-linked aspirin and celecoxib were most effective in decreasing cell growth and inducing apoptosis at the lowest dosages, R-flurbiprofen and ibuprofen were most effective at clinically relevant dosages. A multidrug resistant ovarian cell line is more resistant to growth inhibition by the drugs tested than its non-drug resistant parental counterpart. There was no correlation between the expression of cyclooxygenase-2 (COX-2) and the ability of the drugs to reduce cancer cell survival. All the drugs tested induced an up-regulation in p75 NTR tumor suppressor gene expression in concert with their observed growth inhibiting ability. Inhibition of p75 NTR expression with siRNA reduced the cell growth inhibiting effects of all the drugs tested.

CONCLUSIONS

The method of chemotherapy (i.e., intravascular, intrathecal, oral) might dictate the choice of NSAID/NSAID derivative used to treat/prevent a given type of cancer. Also, the p75 NTR tumor suppressor appears to be a common molecular mechanism that mediates the growth inhibiting effectiveness of these drugs.

COX-2 inhibition: a possible role in the management of prostate cancer?

There is mounting evidence to support a role for cyclooxygenase-2 (COX-2) inhibitors (coxibs) in the management of prostate cancer. This review considers the current evidence base for the use of coxibs in prostate cancer as well as their adverse event profile. A systematic literature review using the search terms 'cyclooxygenase', 'COX-2', 'coxibs', 'cardiovascular risk', and 'prostate cancer' was performed using Medline. Celecoxib appears safer in terms of cardiovascular toxicity than other coxibs, and this may relate to its lower selectivity for the COX-2 enzyme. This lower selectivity also provides rationale for its putative broader anti-cancer effects, via non-COX-2-dependent pathways that affect cell cycle regulation, angiogenesis, and hypoxic modulation. There are also interacting relationships between COX-2, chronic inflammation, and prostate cancer. There is much promise for the coxibs as anti-cancer agents. The future might be to pharmacologically adapt these agents to exert their COX-2 independent mechanisms of action while minimizing their COX-2-dependent adverse cardiovascular effects.

A novel pathway involving melanoma differentiation associated gene-7/interleukin-24 mediates nonsteroidal anti-inflammatory drug-induced apoptosis and growth arrest of cancer cells

Numerous studies show that nonsteroidal anti-inflammatory drugs (NSAIDs) are effective in chemoprevention or treatment of cancer. Nevertheless, the mechanisms underlying these antineoplastic effects remain poorly understood. Here, we report that induction of the cancer-specific proapoptotic cytokine melanoma differentiation associated gene-7/interleukin-24 (MDA-7/IL-24) by several NSAIDs is an essential step for induction of apoptosis and G(2)-M growth arrest in cancer cells in vitro and inhibition of tumor growth in vivo. We also show that MDA-7/IL-24-dependent up-regulation of growth arrest and DNA damage inducible 45 alpha (GADD45alpha) and GADD45gamma gene expression is sufficient for cancer cell apoptosis via c-Jun NH(2)-terminal kinase (JNK) activation and growth arrest induction through inhibition of Cdc2-cyclin B checkpoint kinase. Knockdown of GADD45alpha and GADD45gamma transcription by small interfering RNA abrogates apoptosis and growth arrest induction by the NSAID treatment, blocks JNK activation, and restores Cdc2-cyclin B kinase activity. Our results establish MDA-7/IL-24 and GADD45alpha and GADD45gamma as critical mediators of apoptosis and growth arrest in response to NSAIDs in cancer cells.

Gene expression profiling in R-flurbiprofen-treated prostate cancer: R-Flurbiprofen regulates prostate stem cell antigen through activation of AKT kinase

We have used gene expression profiling to characterize genes regulated by the anti-tumor non-steroidal anti-inflammatory drug (NSAID)-like agent R-flurbiprofen (RFB) in murine TRAMP prostate cancer. Mice with spontaneous, palpable tumors were treated with RFB 25 mg/(kgd) x 7d orally, or vehicle only. RNA was then extracted from tumor tissue and used for microarray analysis with Affymetrix chips. Fifty-eight genes were reproducibly regulated by RFB treatment. One of the most highly up-regulated genes was prostate stem cell antigen (psca). We used TRAMP C1 murine prostate cancer cells to examine potential mechanisms through which RFB could regulate psca. RFB induced dose-dependent expression of PSCA protein, and activity of the psca promoter, in TRAMP C1 cells in culture. Increased psca promoter activity was also seen following treatment of cells with sulindac sulfone, another NSAID-like agent, but not with celecoxib treatment. RFB activation of the psca promoter could be attenuated by co-transfection of dominant-negative akt and h-ras constructs, but not by dominant-negative mek1 plasmids. Immunoblotting revealed that RFB increased expression of phosphorylated AKT at concentrations that stimulated psca promoter activity, and that increased PSCA protein expression. In addition, RFB-dependent up-regulation of PSCA protein expression could be blocked by AKT inhibitors. These data demonstrate that RFB, and possibly other NSAID-like analogs, can increase expression of the psca gene both in vivo and in culture. They further suggest the utility of combining RFB with AKT inhibitors or with monoclonal antibodies targeting PSCA protein, for treatment or prevention of prostate cancer.

Expression of cyclooxygenase-2 in Wilms tumor: immunohistochemical study using tissue microarray methodology

PURPOSE

Cyclooxygenase-2, a key enzyme in prostaglandin biosynthesis, has been shown to be involved in the modulation of cell growth, inflammation and apoptosis. Its involvement in the development of several human neoplasms has also been documented as well as the significant antitumor effects of its inhibitors. To our knowledge cyclooxygenase-2 expression in Wilms tumor has not been studied.

MATERIALS AND METHODS

A tissue microarray multitissue block was prepared from 14 samples of Wilms tumor, each from a different patient, from xenografts derived thereof, and from normal human lung, liver, renal cortex and medulla tissues as controls. Each sample was represented in the block by 3 or 4 cores 0.6 mm in diameter. After serial slicing to 4 mum the histological slides were stained with hematoxylin and eosin, and immunostained with anti-cyclooxygenase-2 antibodies. Immunostaining was graded semiquantitatively according to the percent of stained cells with the cytoplasmic pattern of staining and according to staining intensity.

RESULTS

All authentic human pathological samples except 1 anaplastic Wilms tumor as well as Wilms tumor xenografts expressed cyclooxygenase-2 in all Wilms tumor cellular components except the stroma. Expression was also observed in Wilms tumor lung metastasis and in tumors that overgrew chemotherapy. In comparison, cyclooxygenase-2 expression in normal kidneys was less prominent than in Wilms tumor samples and it was confined to the tubular epithelium in the cortex and medulla.

CONCLUSIONS

Cyclooxygenase-2 expression is characteristic of all nonanaplastic Wilms tumors at all stages. It is similar to the previously observed pan-expression of ErbB2 receptors in these tumors. The potential therapeutic role of cyclooxygenase-2 inhibitors should be evaluated for Wilms tumor.

Non-steroidal anti-inflammatory drug use and prostate cancer in a high-risk population

Animal and laboratory studies suggest that regular use of non-steroidal anti-inflammatory drugs (NSAIDs) may reduce prostate cancer risk. The aim of this study was to investigate the association between NSAID use and prostate cancer in a high-risk population. We included 1299 men who were referred to our university's prostate cancer detection clinic for prostate biopsy between January 1999 and July 2003. Before transrectal ultrasonography and prostate biopsy, all men completed a self-administered questionnaire that included questions on drug use in the preceding 5 years. On average, NSAID users were older than non-users but there was no significant difference in mean baseline prostate-specific antigen (PSA). Four hundred and ninety-four (38%) had biopsy-confirmed prostate cancer. After adjustment for age, family history of prostate cancer and other potential confounders, use of aspirin was associated with a 42% reduction in the odds of prostate cancer detection [95% confidence interval (CI) 0.36-0.91]. Among cases, regular use of NSAIDs was inversely related to the risk of detection of more poorly differentiated cancers and cancers with higher percentage core involvement. These findings support other epidemiological and experimental evidence that suggests that aspirin may be useful in prostate cancer prevention. Further observational studies with adequate case definition and exposure measurements and careful adjustment for detection bias are warranted.

Elevated prostaglandin E2 level via cPLA2--COX-2--mPGES-1 pathway involved in bladder carcinogenesis induced by terephthalic acid-calculi in Wistar rats

To investigate the prostaglandin E2 (PGE2) biosynthetic mechanism in bladder carcinogenesis, we established Wistar rat model of bladder papilloma and transitional cell carcinoma (TCC) induced by 5% terephthalic acid (TPA) treatment. Then, the mRNA level of cytosolic phospholipase A2 (cPLA2), cyclooxygenases (COX)-1 and -2, membrane-bound PGE2 synthases (mPGES)-1 and -2 was detected using reverse transcription polymerase chain reaction (RT-PCR). Immunoblotting was applied to detect the expression of COX-2 protein. Proliferating cell nuclear antigen (PCNA) was determined by immunohistochemistry. In addition, the level of PGE2 was measured by radioimmunoassay (RIA). Bladder papilloma (100%, 8/8) was examined in rats after 24-week treatment, and bladder TCC (80%, 16/20) was found after 48-week treatment. Histopathological changes were not found in control group rats. The incidence of bladder papilloma and TCC in test group was significantly higher than that in control group (P<0.01). The mRNA levels of cPLA2, COX-2 and mPGES-1 in the bladder papilloma and TCC were significantly higher than those in normal bladder (P<0.01), while the mRNA levels of COX-1 and mPGES-2 in TCC were unchanged compared with normal bladder. Bladder TCC exhibited a substantial expression of COX-2 protein. On the contrary, normal bladder tissue barely expresses COX-2 protein. PCNA labeling index (LI) and the level of PGE2 in bladder papilloma are much higher than those in normal bladder (P<0.01), but lower than those in bladder TCC (P<0.05). In conclusion, increasing PGE2 level via cPLA2--COX-2--mPGES-1 pathway may play an important role in rat bladder carcinogenesis. PGE2 may be a biomarker for the development of bladder TCC. cPLA2 and mPGES-1 may be targets for development of novel chemoprevention strategies for bladder TCC.

Cyclooxygenase inhibitors in urinary bladder cancer:in vitroandin vivoeffects

More than 14,000 people die from invasive transitional cell carcinoma (TCC) of the urinary bladder yearly in the United States. Cyclooxygenase (COX)-inhibiting drugs are emerging as potential antitumor agents in TCC. The optimal in vitro or in vivo systems to investigate COX inhibitor antitumor effects have not been defined. The purpose of this study was to determine COX-1 and COX-2 expression and antitumor effects of COX inhibitors in human TCC cell lines (HT1376, RT4, and UMUC3 cells) and xenografts derived from those cell lines. COX-2 expression (Western blot, immunocytochemistry) was high in HT1376, modest in RT4, and absent in UMUC3 cells in vitro. Similarly, COX-2 expression was noted in RT4 but not UMUC3 xenografts. COX-2 expression in HT1376 xenografts was slightly lower than that observed in vitro. None of four COX inhibitors evaluated (celecoxib, piroxicam, valeryl salicylate, and NS398) reduced TCC growth in standard in vitro proliferation assays at concentrations that could be safely achieved in vivo (< or =5 micromol/L). Higher celecoxib concentrations (> or =50 micromol/L) inhibited proliferation and induced apoptosis in all three cell lines. Celecoxib or piroxicam treatment in athymic mice significantly delayed progression of HT1376 xenografts, which express COX-2, but not UMUC3 xenografts that lack COX-2 expression. In conclusion, standard in vitro assays were not useful in predicting COX inhibitor antitumor effects observed in vivo. Athymic mice bearing TCC xenografts provide a useful in vivo system for COX inhibitor studies. Results of this study provide justification for further evaluation of COX inhibitors as antitumor agents against TCC.

Proinflammatory CD4+CD45RBhi Lymphocytes Promote Mammary and Intestinal Carcinogenesis in ApcMin/+ Mice

Cancers of breast and bowel are increasingly frequent in humans. Chronic inflammation is known to be a risk factor for these malignancies, yet cellular and molecular mechanisms linking inflammation and carcinogenesis remain poorly understood. Here, we apply a widely used T-cell transfer paradigm, involving adoptive transfer of proinflammatory CD4+ CD45RB(hi) (T(E)) cells to induce inflammatory bowel disease (IBD) in mice, to investigate roles of inflammation on carcinogenesis in the Apc(Min/+) mouse model of intestinal polyposis. We find that transfer of T(E) cells significantly increases adenoma multiplicity and features of malignancy in recipient Apc(Min/+) mice. Surprisingly, we find that female Apc(Min/+) recipients of T(E) cells also rapidly develop mammary tumors. Both intestinal polyposis and mammary adenocarcinoma are abolished by cotransfer of anti-inflammatory CD4+ CD45RB(lo) regulatory lymphocytes or by neutralization of key proinflammatory cytokine tumor necrosis factor-alpha. Lastly, down-regulation of cyclooxygenase-2 and c-Myc expression is observed coincident with tumor regression. These findings define a novel mouse model of inflammation-driven mammary carcinoma and suggest that epithelial carcinogenesis can be mitigated by anti-inflammatory cells and cytokines known to regulate IBD in humans and mice.

Pro-apoptotic effect of a nitric oxide-donating NSAID, NCX 4040, on bladder carcinoma cells

Nitric oxide-releasing non steroidal anti-inflammatory drugs (NO-NSAIDs) are a promising class of compounds that cause cell cycle perturbations and induce apoptosis in cell lines from different tumors. We investigated the activity of a recently developed NO-NSAID (NCX 4040) in bladder cancer cell lines (HT1376 and MCR). Cells were treated with different drug concentrations for different exposure times. Cytostatic and cytocidal activity was tested by SRB assay and apoptosis was evaluated by TUNEL analysis, ANNEXIN V assay and fluorescence microscopy. To further investigate the cell death-inducing mechanisms of NCX 4040, we analyzed gp-170, caspase expression and mitochondrial membrane potential (Delta Psi) depolarization. NCX 4040 showed a striking cytocidal activity in both cell lines, reaching LC(50) at a 10-microM and 50-microM concentrations in HT1376 and in MCR cells, respectively, after an exposure of only 6 h followed by an 18-h washout. Apoptosis was triggered in up to 90% of cells and was associated with active caspase-3 expression and Delta Psi depolarization in both cell lines after a 6-h exposure. In conclusion, NCX 4040, which probably causes apoptosis via a mitochondrial-dependent mechanism, could prove to be a useful agent for improving bladder cancer treatment.

Non-steroidal anti-inflammatory drugs for the prevention and treatment of cancer

Non-steroidal anti-inflammatory drugs (NSAIDs), both cyclooxygenase-2 (COX-2) selective and nonselective inhibitors, are amongst the most popular medications worldwide. Whilst their anti-inflammatory effect is well known, recent studies have demonstrated an unexpected effect in both the prevention and treatment of several types of cancer. The anticancerous effect of NSAIDs is believed to be mainly due to the inhibition of COX-2, which is overexpressed in many types of cancer and may play a major role in tumourigenesis. In this review, we will describe the possible mechanisms for NSAIDs anticancer effect and summarize the major clinical studies in cancer prevention and treatment. We will also discuss the effect of the recent reports of adverse cardiovascular effects on anticancer research of the selective COX-2 inhibitors.

Regression of mouse prostatic intraepithelial neoplasia by nonsteroidal anti-inflammatory drugs in the transgenic adenocarcinoma mouse prostate model

PURPOSE

Epidemiologic studies have revealed a decreased risk of colon cancer among people who have regularly taken cyclooxygenase (COX)-2 inhibitors such as aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs). Whereas the selective COX-2 inhibitor celecoxib and exisulind, a metabolic product of sulindac, have gained increasing attention as efficacious chemopreventive agents against colon and prostate cancer, not much is known about the underlying molecular targets and mechanisms. Moreover, the side effects of NSAIDs are a major obstacle for large-scale application to the prevention of cancer in humans; for example, in the United States in 1998, there were 16,550 deaths from NSAID-induced gastrointestinal complications. The toxicity associated with these compounds is raising concerns, and more needs to be known about their mode of action and molecular targets.

EXPERIMENTAL DESIGN

We used the transgenic mouse prostate (TRAMP) model, which exhibits similarities with human prostate cancer, including epithelial origin, progression from the PIN stage to adenocarcinoma, and metastasis by a transgene that is hormonally regulated by androgens. In addition to histologically analyzing the PIN lesions of the dorsolateral prostate from TRAMP mice, we delineated the molecular targets and mechanisms of celecoxib and exisulind against mouse PIN lesions. We performed Western blot analysis of the total protein lysate from the tissues of mouse PIN lesions to measure the level of expression of androgen receptor, vascular endothelial growth factor, nuclear factor-kappaB p65, BclII, AKT (total and phosphorylated Ser473), p53, cyclin-dependent kinase inhibitor p21WAF1/CIP1, p27, BAX, and caspase-3 to demonstrate the COX-2-independent mechanism involved in the inhibition of PIN lesions of the dorsolateral prostate by both celecoxib and exisulind.

RESULTS

We found for the first time that (a) both celecoxib and exisulind as dietary supplements induce strong inhibitory effects against prostate cancer at doses of 800 and 500 ppm, respectively, after 16 weeks; (b) the histologic analysis of the dorsolateral prostate after 2 weeks of treatment indicated a reduction of PIN lesions from 75% to 19% with celecoxib and to 16% with exisulind; (c) more importantly, those few PINs and adenocarcinomas in the groups treated with celecoxib or exisulind showed more apoptotic cells, lower levels of proliferating cell nuclear antigen, and a lower number of mitotic cells. To understand the molecular mechanisms involved in the inhibition of PIN lesions, first, we examined the expression of molecular targets involved in angiogenesis and inflammatory processes. It was clearly evident from Western blot analysis of the total protein lysate derived from the dorsolateral prostate tissues with PIN lesions that expression of androgen receptor, vascular endothelial growth factor, nuclear factor-kappaB p65, and BclII is down-regulated more effectively by celecoxib. Down-regulation of AKT protein (total and phosphorylated at Ser473) signaling by celecoxib clearly indicates an inhibition of the survival gene and the pathological process that could otherwise lead to adenocarcinoma.

CONCLUSIONS

Overall, the findings from this study clearly show the effectiveness of celecoxib and exisulind in reducing the PIN lesions by modulating a cascade of molecular targets involved in COX-2-dependent and -independent mechanisms. Whereas these agents are already in clinical trial or in use as chemopreventive agents, findings from this study demonstrate the difference in their mode of action, thus helping us to understand the side effects.

Transitional Cell Hyperplasia and Carcinomas in Urinary Bladders of Transgenic Mice with Keratin 5 Promoter-Driven Cyclooxygenase-2 Overexpression

The inducible form of cyclooxygenase (COX), COX-2, is up-regulated in many epithelial cancers and its prostaglandin products increase proliferation, enhance angiogenesis, and inhibit apoptosis in several tissues. Pharmacologic inhibition and genetic deletion studies showed a marked reduction of tumor development in colon and skin. COX-2 has also been strongly implicated in urinary bladder cancer primarily by studies with nonselective COX- and COX-2-selective inhibitors. We now show that forced expression of COX-2, under the control of a keratin 5 promoter, is sufficient to cause transitional cell hyperplasia (TCH) in 17% and 75% of the heterozygous and homozygous transgenic lines, respectively, in an age-dependent manner. TCH was strongly associated with inflammation, primarily nodules of B lymphocytes; some T cells and macrophage infiltration were also observed. Additionally, transitional cell carcinoma was observed in approximately 10% of the K5.COX-2 transgenic mice; no TCH or transitional cell carcinoma was observed in wild-type bladders. Immunohistochemistry for vascular proliferation and vascular endothelial growth factor showed significant increases above that in wild-type urinary bladders. Our results suggest that overexpression of COX-2 is sufficient to cause hyperplasia and carcinomas in the urinary bladder. Therefore, inhibition of COX-2 should continue to be pursued as a potential chemopreventive and therapeutic strategy.

Pretreatment tumor prostaglandin E2 concentration and cyclooxygenase-2 expression are not associated with the response of canine naturally occurring invasive urinary bladder cancer to cyclooxygenase inhibitor therapy

The purpose of this study was to determine the extent to which pretreatment prostaglandin E2 (PGE2) concentration and cyclooxygenase-2 (cox-2) expression could be used to predict the antitumor activity of cox inhibitor treatment in naturally occurring canine transitional cell carcinoma of the urinary bladder (TCC). Snap frozen tissues (to measure PGE2) and formalin-fixed TCC samples (for cox-2 immunohistochemistry) were obtained by cystoscopy or surgery. Complete tumor staging was performed before and after one month of treatment with the cox inhibitor, piroxicam (0.3 mg/kg q24 h po). The pretreatment PGE2 concentration ranged from 57 to 1624 ng/g of TCC tissue; n=18 dogs). Cox-2 immunoreactivity was observed in all TCC samples. There was no association between PGE2 concentration, cox-2 expression, and change in tumor volume with piroxicam treatment. In conclusion, cox-2 expression or PGE2 concentration alone, or the combination of the two was not useful in predicting response to piroxicam treatment in canine TCC.