Induction of apoptosis in colon cancer cells by nonsteroidal anti-inflammatory drugs

Intake of Red and Processed Meat, Use of Non-Steroid Anti-Inflammatory Drugs, Genetic Variants and Risk of Colorectal Cancer: A Prospective Study of the Danish "Diet, Cancer and Health" Cohort

Red and processed meat have been associated with increased risk of colorectal cancer (CRC), whereas long-term use of non-steroid anti-inflammatory drugs (NSAIDs) may reduce the risk. The aim was to investigate potential interactions between meat intake, NSAID use, and gene variants in fatty acid metabolism and NSAID pathways in relation to the risk of CRC. A nested case-cohort study of 1038 CRC cases and 1857 randomly selected participants from the Danish prospective “Diet, Cancer and Health” study encompassing 57,053 persons was performed using the Cox proportional hazard model. Gene variants in SLC25A20, PRKAB1, LPCAT1, PLA2G4A, ALOX5, PTGER3, TP53, CCAT2, TCF7L2, and BCL2 were investigated. CCAT2 rs6983267 was associated with the risk of CRC per se (p < 0.01). Statistically significant interactions were found between intake of red and processed meat and CCAT2 rs6983267, TP53 rs1042522, LPCAT1 rs7737692, SLC25A20 rs7623023 (p_interaction = 0.04, 0.04, 0.02, 0.03, respectively), and the use of NSAID and alcohol intake and TP53 rs1042522 (p_interaction = 0.04, 0.04, respectively) in relation to the risk of CRC. No other consistent associations or interactions were found. This study replicated an association of CCAT2 rs6983267 with CRC and an interaction between TP53 rs1042522 and NSAID in relation to CRC. Interactions between genetic variants in fatty acid metabolism and NSAID pathways and the intake of red and processed meat were found. Our results suggest that meat intake and NSAID use affect the same carcinogenic mechanisms. All new findings should be sought replicated in independent prospective studies. Future studies on the cancer-protective effects of aspirin/NSAID should include gene and meat assessments.

Nonsteroidal anti-inflammatory drug use after 3 years of aspirin use and colorectal adenoma risk: observational follow-up of a randomized study

BACKGROUND

Frequent use of nonsteroidal anti-inflammatory drugs (NSAIDs) has been shown to reduce the risk of colorectal adenomas in randomized trials. We examined the persistence of the protective effect after the cessation of randomized aspirin treatment and whether it is affected by the duration and frequency of subsequent NSAID use.

METHODS

We used data from the Aspirin/Folate Polyp Prevention Study (AFPPS), in which 1121 subjects were randomly assigned to receive placebo or aspirin (81 or 325 mg/d) for 3 years. After the end of treatment and a follow-up colonoscopy, AFPPS participants were invited to remain under follow-up until their next surveillance colonoscopies, scheduled 3-5 years later. Information regarding use of NSAIDs during posttreatment follow-up was gathered periodically via questionnaires. Average weekly NSAID use was classified as sporadic (<2 days per week), moderate (2 to <4 days per week), or frequent (>or=4 days per week). The analysis was stratified according to randomized aspirin groups and posttreatment NSAID use; placebo subjects who later were sporadic NSAID users formed the reference group. The primary outcomes were all adenomas and advanced lesions. Adjusted relative risks and 95% confidence intervals were computed with generalized linear models. All statistical tests were two-sided.

RESULTS

A total of 850 subjects underwent a posttreatment colonoscopy, on average 4 years after the end of study treatment. The protective effect of 81 mg of aspirin for colorectal adenomas persisted with continued posttreatment NSAID use. The risk of any adenoma among frequent NSAID users was 26.8% vs 39.9% among placebo subjects who later used NSAIDs sporadically (adjusted relative risk = 0.62, 95% confidence interval [CI] = 0.39 to 0.98; P(trend) with NSAID use frequency = .03). The unadjusted absolute risk reduction was 13.1 percentage points (95% CI = -0.3 to 26.5 percentage points) (P = .07). Results for 325 mg of aspirin were similar, although not statistically significant. For advanced lesions, small numbers of endpoints limited the analysis, but findings among subjects randomly assigned to 81 mg of aspirin suggested a protective association regardless of posttreatment NSAID use.

CONCLUSION

Long-term and frequent use of NSAIDs may enhance the chemopreventive effect of aspirin against colorectal neoplasia.

Genetic polymorphisms in TP53, nonsteroidal anti-inflammatory drugs and the risk of colorectal cancer: evidence for gene-environment interaction?

OBJECTIVE

Substantial evidence indicates that nonsteroidal anti-inflammatory drugs protect against colorectal cancer by altering cell cycle progression and/or inducing apoptosis, whereas p53 protein is crucial to maintaining cell-cycle arrest and regulating DNA repair, differentiation, and apoptosis. Genetic variants in TP53 gene might therefore influence colorectal cancer risk and modify the effects of nonsteroidal anti-inflammatory drugs. We assessed the association of TP53 Arg72Pro and p53PIN3 polymorphisms with colorectal cancer risk and their possible interaction with nonsteroidal anti-inflammatory drug use.

METHODS

We included 467 cases and 563 controls from a population-based case-control study. Multivariate logistic regression analysis was used to estimate the association between genotypes, environmental exposures and colorectal cancer risk, adjusting for potential confounders.

RESULTS

Odds ratios of colorectal cancer were 0.75 (95% confidence interval, 0.57-0.99) for TP53 72Pro carriers compared with those homozygous for the TP53 72Arg allele and 0.78 (95% confidence interval, 0.58-1.05) for p53PIN3 A2 carriers compared with p53PIN3 A1A1. Risks differed by nonsteroidal anti-inflammatory drug use. For both investigated TP53 polymorphisms, we found that the colorectal cancer risk associated with regular nonsteroidal anti-inflammatory drug use was statistically significantly modified by the TP53 genotype (P values for interaction=0.049 and 0.034, respectively), whereby a substantial protective effect of nonsteroidal anti-inflammatory drug use was observed for homozygous carriers of the 72Arg allele and of the PIN3 A1 allele (odds ratio 0.44; 95% confidence interval, 0.30-0.65 and odds ratio, 0.45; 95% confidence interval, 0.31-0.65). The interaction between nonsteroidal anti-inflammatory drugs and TP53 genetic polymorphisms was confirmed by haplotype analysis.

CONCLUSIONS

These data suggest that the TP53 genotype may modify the influence of nonsteroidal anti-inflammatory drug use on the risk of colorectal cancer. A direct proof of functional analysis is warranted to confirm these findings.

Inhibition of angiogenic tubule formation and induction of apoptosis in human endothelial cells by the selective cyclooxygenase-2 inhibitor 5-bromo-2-(4-fluorophenyl)-3-(methylsulfonyl) thiophene (DuP-697)

There are indications that inhibitors of the cyclooxygenase-2 (COX-2) enzyme may cause inhibition of angiogenesis, proliferation of endothelial cells and induce apoptosis in cell systems. The concentrations of inhibitors required for such effects are however much higher than those needed to inhibit COX-2, suggesting that the latter may not be involved in these actions of the drugs. We have however generated data that strongly indicates a critical role for COX-2 suppression in the inhibition of angiogenesis and induction of apoptosis in human cultured umbilical vein endothelial cells (HUVECs) by the selective cyclooxygenase-2 (COX-2) inhibitor 5-bromo-2-(4-fluorophenyl)-3-(methylsulfonyl) thiophene (DuP-697). DuP-697 concentration-dependently inhibited prostaglandin E(2) (PGE(2)) production by HUVECs and at its known IC(50) for COX-2 inhibition of 10 nM inhibited basal and vascular endothelial cell growth factor (VEGF)-induced PGE(2) production by 80% and 85% respectively. DuP-697 also induced apoptosis as shown by FACs analysis, an increase in chromatin condensation and DNA laddering in HUVECS treated with the drug. Moreover, these effects were reversed by PGE(2) and by VEGF. In parallel studies, DuP-697 induced caspases 3, 8 and 9, with the caspase-3 specific inhibitor N-Acetyl-Asp-Glu-Val-Asp-al (DEVD-CHO) blocking the induction of apoptosis. Capillary-like tubule formation by HUVECs cultured on Matrigel was inhibited by DuP-697 and this inhibition was prevented by PGE(2) but not by DEVD-CHO. These results indicate that the induction of apoptosis and inhibition of tubule formation by DuP-697 involves the inhibition of COX-2 and that whereas the induction of apoptosis is caspase-dependent, the inhibition of tubule formation occurs through a caspase-independent mechanism.

Interaction of Calcium Supplementation and Nonsteroidal Anti-inflammatory Drugs and the Risk of Colorectal Adenomas

BACKGROUND

Calcium and aspirin have both been found to be chemopreventive against colorectal neoplasia. However, the joint effect of the two agents has not been well investigated.

METHODS

To explore the separate and joint effects of calcium and aspirin/nonsteroidal anti-inflammatory drugs (NSAID), we used data from two large randomized clinical trials among patients with a recent history of colorectal adenomas. In the Calcium Polyp Prevention Study, 930 eligible subjects were randomized to receive placebo or 1,200 mg of elemental calcium daily for 4 years. In the Aspirin/Folate Polyp Prevention Study, 1,121 eligible subjects were assigned to take placebo, 81 mg of aspirin, or 325 mg of aspirin daily for 3 years. In each study, subjects completed a validated food frequency questionnaire at enrollment and were asked periodically about medications and supplements used. Recurrent adenomas and advanced adenomas were the end points considered. We used generalized linear models to assess the separate and combined effects of aspirin (or NSAIDs) and calcium supplementation (or dietary calcium) and the interactions between these exposures.

RESULTS

In the Calcium Trial, subjects randomized to calcium who also were frequent users of NSAIDs had a reduction of risk for advanced adenomas of 65% [adjusted risk ratio (RR), 0.35; 95% confidence interval (95% CI), 0.13-0.96], and there was a highly significant statistical interaction between calcium treatment and frequent NSAID use (P(interaction) = 0.01). Similarly, in the Aspirin Trial, 81 mg aspirin and calcium supplement use together conferred a risk reduction of 80% for advanced adenomas (adjusted RR, 0.20; 95% CI, 0.05-0.81); there was a borderline significant statistical interaction between the two treatments (P(interaction) = 0.09). In this trial, we found similar trends when we considered baseline dietary calcium intake instead of calcium supplements. For all adenomas considered together, the interactive patterns were not consistent.

CONCLUSION

Data from two different randomized clinical trials suggest that calcium and NSAIDs may act synergistically to lower the risk of advanced colorectal neoplastic polyps.

Activity of the non-steroidal anti-inflammatory drug indomethacin against colorectal cancer

A substantial body of evidence from rodent colon carcinogenesis models, in vitro experiments with human colorectal cancer cells and limited clinical observations in humans suggest that the non-steroidal anti-inflammatory drug indomethacin has anti-colorectal cancer activity. However, although many mechanisms of the anti-neoplastic activity of indomethacin have been suggested, e.g., cyclooxygenase inhibition and peroxisome proliferator-activated receptor gamma activation, the precise relevance of the majority of in vitro pharmacological observations to the in vivo anti-neoplastic activity of indomethacin remains unclear. Herein, we review the existing literature describing the chemopreventative and chemotherapeutic efficacy of indomethacin against colorectal cancer, and draw together the disparate literature describing potential mechanisms of action of indomethacin in human colorectal cancer cells in vitro. Although indomethacin itself has significant adverse effects, including serious upper gastrointestinal toxicity, the development of novel derivatives that may have an improved safety profile means that further investigation of the anti-colorectal cancer activity of indomethacin is warranted.

Regular aspirin use and lung cancer risk

BACKGROUND

Although a large number of epidemiological studies have examined the role of aspirin in the chemoprevention of colon cancer and other solid tumors, there is a limited body of research focusing on the association between aspirin and lung cancer risk.

METHODS

We conducted a hospital-based case-control study to evaluate the role of regular aspirin use in lung cancer etiology. Study participants included 868 cases with primary, incident lung cancer and 935 hospital controls with non-neoplastic conditions who completed a comprehensive epidemiological questionnaire. Participants were classified as regular aspirin users if they had taken the drug at least once a week for at least one year.

RESULTS

Results indicated that lung cancer risk was significantly lower for aspirin users compared to non-users (adjusted OR = 0.57; 95% CI 0.41-0.78). Although there was no clear evidence of a dose-response relationship, we observed risk reductions associated with greater frequency of use. Similarly, prolonged duration of use and increasing tablet years (tablets per day x years of use) was associated with reduced lung cancer risk. Risk reductions were observed in both sexes, but significant dose response relationships were only seen among male participants. When the analyses were restricted to former and current smokers, participants with the lowest cigarette exposure tended to benefit most from the potential chemopreventive effect of aspirin. After stratification by histology, regular aspirin use was significantly associated with reduced risk of small cell lung cancer and non-small cell lung cancer.

CONCLUSIONS

Overall, results from this hospital-based case-control study suggest that regular aspirin use may be associated with reduced risk of lung cancer.