Effect of non-steroidal anti-inflammatory drugs on colon carcinoma Caco-2 cell responsiveness to topoisomerase inhibitor drugs

Design and Synthesis of Aspirin-chalcone Mimic Conjugates as Potential Anticancer Agents

BACKGROUND

Extensive research has been conducted on aspirin, a widely recognized NSAID medication, regarding its potential as an anticancer agent. Studies have revealed its ability to trigger cell death in different types of cancer cells.

METHODS

A set of aspirin-chalcone mimic conjugates 5a-k and 6a-d utilizing the freshly prepared acid chloride of aspirin moiety has been designed and synthesized. To evaluate the newly developed compounds, the NCI 60- cell line panel was employed to assess their anti-proliferative properties. Subsequently, cell cycle analysis was conducted along with an examination of the compounds' impact on the levels of p53, Bax, Bcl-2, active caspase- 3, and their inhibition mechanism of tubulin polymerization.

RESULTS

Derivative 6c displayed the best anticancer activity among the tested series while 6d was the best against breast cancer MDA-MB-468, therefore both of them were selected for the 5-dose stage, however, targeting MDA-MB-468, PI-flow cytometry of compound 6d proved the triggered cell growth arrest at the G1/S phase avoiding the mitotic cycle in MDA-MB-468 cells. Similarly, the upregulation of oncogenic parameters such as caspase-3, p53, and Bax/Bcl-2, along with the inhibition of PARP-1 enzyme level, was observed with compound 6d. This compound also exhibited a significant ability to induce apoptosis and disrupt the intracellular microtubule network through a promising activity as a tubulin polymerization inhibitor with IC50 = 1.065 ± 0.024 ng/ml. Furthermore, to examine the manner in which compound 6d binds to the active pocket of the tubulin polymerization enzyme, a molecular docking study was conducted.

CONCLUSION

The study indicated that compound 6d could be a powerful microtubule-destabilizing agent. Therefore, further research on 6d could be worthwhile.

Non-steroidal anti-inflammatory drugs are safe with respect to the transcriptome of human dermal fibroblasts

Non-steroidal anti-inflammatory drugs (NSAIDs) provide important benefits to millions of patients, but are associated with a number of serious adverse events. These adverse drug reactions are an important clinical issue and a serious public health risk. While most unfortunate responses in human to NSAIDs are mild and may disappear after decreasing the dose or withdrawal of the drug, some of them can produce serious outcomes. Currently, little is known regarding the effects of NSAIDs on global RNA expression in normal, non-transformed cells. Therefore, in this report, the effect of NSAIDs, COX-nonspecific and COX-2-specific inhibitors, indomethacin and nimesulide respectively, commonly used medications worldwide for the reduction of pain, fever, inflammation and stiffness, on transcriptomic signature of human dermal fibroblasts was investigated. A total of 3803 differentially expressed genes with a fold change greater than or equal to 1.3 and below than or equal to 0.7 for whole genome transcripts, with a P value of < 0.05 were identified in response to all applied conditions. We found that although the total number of deregulated genes was relatively high at such criteria, changes in fibroblast transcriptome profile after treatment at selected experimental conditions were however smallish, as the selected drugs slightly modulate transcriptome with only a few genes with expression altered a bit more than twice. Nevertheless, transcriptomic data has its own limitations and it cannot reflect all post-transcriptional changes, which in turn may cause same risks, especially for a long time of medication.

Protective effects of essential oil of Citrus limon against aspirin-induced toxicity in IEC-6 cells

Aspirin, one of the widely used nonsteroidal anti-inflammatory drugs, is the most highly consumed pharmaceutical product in the world. However, it has several side effects in cells. This study was designed to investigate the antioxidative activity and cytoprotective effects of essential oil of Citrus limon (EOC) extracted from leaves against aspirin-induced damages in the rat small intestine epithelial cells (IEC-6). Biochemical indicators were used to assess cytotoxicity and oxidative damages caused by aspirin treatment on IEC-6. Our results showed that the chemical characterization of EOC identified 25 compounds representing 98.19% of the total oil. The major compounds from this oil were z-citral (53.21%), neryl acetate (13.06%), geranyl acetate (10.33%), and limonene (4.23%). Aspirin induced a decrease in cell viability as well as an increase in superoxide dismutase (SOD) and catalase (CAT) activities. Contrariwise, the co-exposure of cells to aspirin and EOC alleviated every above syndrome by an increase in cell survival and decrease in SOD and CAT activities. In conclusion, the essential oil of C. limon has a potent cytoprotective effect against aspirin-induced toxicity in IEC-6 cells.

Expression of p27, COX-2, MLH1, and MSH2 in young patients with colon carcinoma and correlation with morphologic findings

Despite an overall decrease in colorectal carcinoma incidence, rates of colorectal carcinoma have increased substantially in patients aged less than 40 years. Several authors have characterized morphologic features of colorectal carcinoma in young patients, with variable results. To date, there has been 1 detailed molecular and immunohistochemical study in young patients with colorectal carcinoma. We sought to expand the data regarding young patients with colorectal carcinoma by a detailed assessment of morphologic features and by assaying expression of p27, COX-2, MLH1, and MSH2, markers with prognostic or therapeutic implications in colorectal carcinoma. We searched our pathology database from 1985 to 2009 and, after exclusion of cases with insufficient data or neoadjuvant therapy, identified a study population of 23 patients aged 40 or younger, 35 patients between 41 and 49 years of age, and a control group of 83 colorectal carcinoma patients aged 50 or older. Younger patients had higher tumor grade (P = .0085), with a trend toward mucinous differentiation and lymphovascular and perineural invasion. Loss of MSH2 was more prominent in younger patients (P = .02). Loss of p27 expression was not associated with age, but was associated with higher tumor stage (P = .0278), mucinous/signet ring differentiation (P = .0185), loss of either MLH1 or MSH2 (P = .0035), and larger tumor size (P = .0019). There was a trend toward lower COX-2 expression in younger patients, with less COX-2 expression relative to previously published data. Our findings support some prior reports regarding morphologic features in colorectal carcinoma in young patients and provide novel data on expression of several markers in this population.

Chemopreventive effects of non-steroidal anti-inflammatory drugs in early neoplasm of experimental colorectal cancer: an apoptosome study

PURPOSE

Apoptosis is a highly regulated mechanism of cell death where pro-apoptotic proteins and caspases play an important role. Activation of pro-caspases at a definite time is essential to control the whole caspase cascade. Mitochondrion contains some pro-apoptotic proteins, which need to come out in cytoplasm for apoptotic function such as Cytochrome c (Cyt c), while the Bcl-2 protein family works as the guard of mitochondrial membrane and prevents the escape of Cyt c. Once Cyt c is out in cytoplasm, it binds with Apaf-1 (another pro-apoptotic protein also essential for proper cell differentiation) and pro-caspase-9, forming the Apoptosome complex. In this study, the role of two non-steroidal anti-inflammatory drugs (NSAIDs), Diclofenac and Celecoxib, in experimentally induced early neoplasm of colon via apoptosome mechanism had been studied. It has been recognized that the prolonged use of NSAIDs has its effect on reducing the risk of colorectal cancer through apoptotic pathways. However, the role of NSAIDs in respect of apoptosome is not clear.

METHODS

Western blotting and immunohistochemistry were performed, along with morphological and histological analysis.

RESULTS

According to the expression levels of Cytochrome c, Apaf-1, Caspases, and Bcl-2, it was observed that NSAIDs do follow the mitochondrial or intrinsic pathway of apoptosis.

CONCLUSION

The effects of Diclofenac and Celecoxib on the expression of pro- and anti-apoptotic proteins have been observed, which may constitute the mechanism by which the NSAIDs are efficient in controlling the proliferation of neoplasm in the colon.

Circadian Timing in Cancer Treatments

The circadian timing system is composed of molecular clocks, which drive 24-h changes in xenobiotic metabolism and detoxification, cell cycle events, DNA repair, apoptosis, and angiogenesis. The cellular circadian clocks are coordinated by endogenous physiological rhythms, so that they tick in synchrony in the host tissues that can be damaged by anticancer agents. As a result, circadian timing can modify 2- to 10-fold the tolerability of anticancer medications in experimental models and in cancer patients. Improved efficacy is also seen when drugs are given near their respective times of best tolerability, due to (a) inherently poor circadian entrainment of tumors and (b) persistent circadian entrainment of healthy tissues. Conversely, host clocks are disrupted whenever anticancer drugs are administered at their most toxic time. On the other hand, circadian disruption accelerates experimental and clinical cancer processes. Gender, circadian physiology, clock genes, and cell cycle critically affect outcome on cancer chronotherapeutics. Mathematical and systems biology approaches currently develop and integrate theoretical, experimental, and technological tools in order to further optimize and personalize the circadian administration of cancer treatments.

Aspirin reduces the outcome of anticancer therapy in Meth A-bearing mice through activation of AKT-glycogen synthase kinase signaling

Aspirin displays, at millimolar concentrations, several mechanisms independent from its ability to inhibit cyclooxygenases. Occasionally, the mechanisms displayed in vitro have been clearly related to an effect of clinical relevance in vivo. An expanding literature has been focusing on the cytoprotective effect of aspirin in neurodegenerative disorders and the activation of AKT pathway in neuroprotection and induction of resistance to anticancer drugs. In this work, we tested the ability of aspirin to activate the AKT survival pathway in methylcholanthrene-induced fibrosarcoma cells (Meth A) transplanted into BALB/c nude mice and the clinical effect of aspirin cotreatment during etoposide (VP-16)-based anticancer therapy. We found that cotreatment with aspirin reduced VP-16-induced apoptosis and activated AKT in vitro and in vivo. In Meth A-bearing mice, aspirin administration also activated glycogen synthase kinase-3 and reduced the activity and the efficacy of anticancer therapy in VP-16 cotreated animals. Our data suggest that the antiapoptotic effect of aspirin operates in vivo through the activation of AKT-glycogen synthase kinase pathway causing a decrease in the outcome of VP-16-based therapy. These findings could have clinical relevance in treatment of human malignancies.

Heme oxygenase-1 inhibits apoptosis in Caco-2 cells via activation of Akt pathway

Heme oxygenase-1 can play a protective role against cellular stress. In colon cancer cells, these effects would be relevant to oncogenesis and resistance to chemotherapy. The aim of the study was to examine the effects of heme oxygenase-1 induction on cell survival in a human colon cancer cell line, Caco-2. Serum deprivation induced apoptosis, reduced Akt and p38 phosphorylation, and increased p21(Cip/WAF1) levels. Heme oxygenase-1 induction by treatment with cobalt protoporphyrin IX resulted in resistance to apoptosis, activation of Akt, reduction in p21(Cip/WAF1) levels and modification of bcl2/bax ratio towards survival. Indomethacin reduced apoptosis but in contrast to heme oxygenase-1, arrested cells in G0/G1. Apoptosis was also inhibited by the heme oxygenase metabolites bilirubin and biliverdin but the CO donor tricarbonyldichlororuthenium(II) dimer did not exert significant effects. Protection against apoptosis in cells treated with cobalt protoporphyrin IX was reverted by incubation with heme oxygenase-1 small interfering RNA. This study shows an antiapoptotic effect of heme oxygenase-1 in colon cancer cells which could be mediated by the formation of bilirubin and biliverdin. Our results support an antiapoptotic role for HO-1 in these cells and provide a mechanism by which overexpression of HO-1 may promote tumor resistance to stress in conditions of limited nutrient supply. We have extended these observations by demonstrating that these effects are independent of p38 but are mediated via Akt pathway.

Cyclooxygenase-2 inhibition sensitizes human colon carcinoma cells to TRAIL-induced apoptosis through clustering of DR5 and concentrating death-inducing signaling complex components into ceramide-enriched caveolae

Cyclooxygenase-2 (COX-2) is up-regulated in human colon carcinomas, and its inhibition is associated with a reduction in tumorigenesis and a promotion of apoptosis. However, the mechanisms responsible for the antitumor effects of COX-2 inhibitors and how COX-2 modulates apoptotic signaling have not been clearly defined. We have shown that COX-2 inhibition sensitizes human colon carcinoma cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis by inducing clustering of the TRAIL receptor DR5 at the cell surface and the redistribution of the death-inducing signaling complex components (DR5, FADD, and procaspase-8) into cholesterol-rich and ceramide-rich domains known as caveolae. This process requires the accumulation of arachidonic acid and sequential activation of acid sphingomyelinase for the generation of ceramide within the plasma membrane outer leaflet. The current study highlights a novel mechanism to circumvent colorectal carcinoma cell resistance to TRAIL-mediated apoptosis using COX-2 inhibitors to manipulate the lipid metabolism within the plasma membrane.

Effects of the combination of topoisomerase I inhibitors and celecoxib, a selective cylooxygenase-2 inhibitor on colorectal cancer

AIM: To investigate the antitumor properties of camptothecins (CPTs) combined with celecoxib, a selective cylooxygenase-2 (COX-2) inhibitor, in vitro and in vivo, and the effects of celecoxib on irinotecan (CPT-11)-induced diarrhea in mice.

METHODS: Four human colon cancer cell lines, HT-29, HCT-8, HCT-116 and Caco-2 were exposed to the increasing concentrations (10^-5, 10^-4, 10^-3,10^-2, 10^-1, 1, 10,100 μmol/L) of three topoisomerase I (Topo I) inhibitors, CPT-11, CPT and topotecan (TPT), and celecoxib (1 and 5 μmol/L) as well as a combination of each Topo I inhibitor. Then MTT assay was performed to evaluate the effects of adjunct use of celecoxib on the chemosensitivity of colon cancer cells to CPTs. HT-29 cells were divided into control group, celecoxib treatment group, CPT treatment group and combined CPT with celecoxib treatment group. Flow cytometry was used to evaluate the apoptotic rates and cell cycle distribution. The expression of COX-2 and apoptosis-related proteins (Bcl-2, Caspase-3 and P53) were determined by immunocytochemical method. HT-29 cell line-xenografts model was established. The nude mice bearing tumor were divided into five groups, namely control group, CPT-11 (25 mg/kg per day) treatment group, celecoxib (60 mg/kg) treatment group and combined celecoxib (30 mg/kg and 60 mg/kg, respectively) with CPT-11 treatment group. The effects of the drugs on tumor growth and the severity of late diarrhea induced by CPT-11 were assessed.

RESULTS: Celecoxib significantly decreased the IC₅₀ of the CPTs in the four colon cancer cell lines in vitro, but the reduction degrees of IC₅₀ depended on the level of COX-2 expression. In HT-29 cells, the apoptotic rates were 51.4% in co-treated groups (24.4% in CPT treated groups, P<0.01), and the proportion in the G0/G1 phase were 49.1% in co-treated group (5.5% in CPT treated groups, P<0.01). The expression of COX-2 and Bcl-2 were down-regulated, but the expression of P53 and Caspase-3 were up-regulated after co-treatment with CPT and celecoxib in HT-29 cells. In vivo, treatment with celecoxib at 60 mg/kg in conjunction with CPT-11 (25 mg/kg per day for three consecutive days) significantly reduced tumor growth by 78.77% (P<0.01 vs control group; P<0.05 vs CPT-11 group), and decreased the score and rate of diarrhea induced by CPT-11 (0.330.52 vs 2.33±0.82, P<0.01; 16.67% vs 83.33%, P<0.05). Besides, celecoxib at 60 mg/kg improved the body weight of the mice (17.54±1.13 g vs 14.56±2.16 g, P<0.05).

CONCLUSION: Celecoxib enhances antitumor properties of CPTs in colon cancer in vitro and in vivo, and this enhancement may be associated with the apoptosis increase and cell cycle arrest. Additionally, celecoxib reduces the severity of diarrhea and body weight loss induced by CPT-11.

Apoptosis induced by aspirin and 5-fluorouracil in human colonic adenocarcinoma cells

Various biochemical, clinical and epidemiological studies have shown that aspirin (ASA) and other nonsteroidal anti-inflammatory drugs (NSAIDs) demonstrate antineoplastic properties, particularly in the gastrointestinal tract, inhibiting the proliferation of colorectal cancer cells. The mechanism of action may be prostaglandin mediated through inhibition of the COX enzymatic system. This includes two iso-enzymes, COX-I and COX-II, working in concert with the activation of apoptosis, activation of immune surveillance, inhibition of proliferation, and inhibition of carcinogen activation. 5-Fluorouracil (5-FU) has demonstrated activity against colorectal cancer, leading to apoptosis of neoplastic cells. We evaluated the effects of varying doses of ASA (0.5, 1, 1.5 mM), both as a single agent and in combination with 5-FU (50 microg) in HT-29, a colon adenocarcinoma cell line. Proliferation assays showed that aspirin at a concentration of 1 mM inhibits cell growth. Cells treated with ASA, both alone and in combination with 5-FU, demonstrated apoptotic activity with the up-regulation of Bax protein, which is consistent with 5-FU anticancer treatment. Furthermore, there was synergistic cell death with ASA and 5-FU. DNA fragmentation, TUNEL, and trypan blue exclusion methods indicated that a combination of ASA and 5-FU induces apoptosis in cells in a time- and concentration-dependent manner. This study serves to further elucidate the mechanism of action of ASA, and ASA in combination with 5-FU, in colorectal cancer as evidenced by its effect on the HT-29 cell line.

Cyclooxygenase-2 inhibition in colorectal cancer: Boom or bust?

Currently, combination chemotherapy represents the standard of care treatment for patients with metastatic colorectal cancer in the United States. Despite recent improvements with the addition of biologic agents, novel treatment approaches are needed to further benefit patients. Cyclooxygenase (COX)-2 inhibition represents one such possibility. COX-2 is highly expressed in colorectal tumor neovasculature and nodal and liver metastases, and expression of COX-2 correlates with tumor stage and patient survival in selected series. COX-2 may be related to colorectal cancer development and propagation through multiple mechanisms, including stimulation of growth, migration, and invasiveness, resistance to apoptosis, and enhancement of angiogenesis. Epidemiologic data suggest nonsteroidal anti-inflammatory drugs (NSAIDs) might prevent development of colorectal cancers, and preclinical data suggest selective COX-2 inhibitors might be additive or synergistic with specific chemotherapeutic agents used in the treatment of colorectal cancer. Despite the lack of published phase I data and the limited, preliminary results of phase II studies, combinations of celecoxib and standard colorectal cancer chemotherapy have entered randomized trials. It is too early to definitively state whether COX-2 inhibition represents a major breakthrough in the treatment of colorectal cancer. Pending the results of ongoing and planned phase III studies, use of COX-2 inhibitors as single agents or incorporation of COX-2 inhibition into combined modality therapy of colorectal cancer should be limited to the setting of clinical trials.

Cyclooxygenase-2 (COX-2) inhibitors sensitize tumor cells specifically to death receptor-induced apoptosis independently of COX-2 inhibition

Cyclooxygenase-2 (COX-2) is involved in diverse processes such as inflammation, carcinogenesis and apoptosis. As COX-2 inhibitors interfere with these processes, inhibition of COX-2 has been suggested as a promising anticancer treatment. However, the role of COX-2 in modulation of apoptosis as well as the death pathways affected by COX-2 inhibitors are poorly characterized. Here we demonstrate that the selective COX-2 inhibitors NS-398 and nimesulide increased TNF sensitivity of TNF-resistant HeLa H21 and TNF-sensitive HeLa D98 cells, although this cytokine induced significant COX-2 activity, as judged by prostaglandin E(2) (PGE(2)) production, only in H21 cells. TNF did also not induce PGE(2) production in MCF-7/casp-3 cells stably expressing COX-2; however, nimesulide strongly enhanced TNF-induced apoptosis in these cells. Furthermore, COX-2 activity in HeLa H21 cells could be inhibited by NS-398 concentrations that were 10 000-fold lower compared to those required for the induction of cell death. Most intriguingly, sensibilization to apoptosis was specifically observed in response to activation of death receptors. Not only TNF-induced cell death but also apoptosis triggered by the CD95 and TRAIL receptors was enhanced by nimesulide. In contrast, apoptosis induced by the anticancer drugs doxorubicine and etoposide that target the mitochondrial death pathway remained unaffected. Together, our data suggest that COX-2 inhibitors overcome apoptosis resistance and selectively sensitize tumor cells to the extrinsic death receptor-induced apoptotic pathway independently of COX-2.

Aspirin protects Caco-2 cells from apoptosis after serum deprivation through the activation of a phosphatidylinositol 3-kinase/AKT/p21Cip/WAF1pathway

Our previous studies indicated that millimolar doses of aspirin induced growth arrest and resistance to anticancer drug treatment in Caco-2 cells. The present study was designed to better elucidate at the molecular level the effect of aspirin treatment on pathways that regulate cell death during serum withdrawal. Caco-2 cells were cultured under serum deprivation in the presence or absence of aspirin. Effects on cell cycle, phosphatidylinositol 3-kinase (PI3-kinase) and mitogen-activated protein (MAP) kinase pathways were investigated. We found that aspirin, but not the selective cyclooxygenase-2 inhibitor N-[2-(cyclohexyloxyl)-4-nitrophenyl]-methane sulfonamide (NS-398); prevented apoptosis and G2/M transition after prolonged Caco-2 cells serum deprivation. Aspirin-dependent inhibition of apoptosis and G2/M transition was prevented by treatment with the PI3-kinase inhibitor 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY294002), but not with the MAP kinase kinase inhibitor 2'-amino-3'-methoxyflavone (PD98059). The effects of aspirin were mediated at molecular levels, through activation of PI3-kinase/AKT pathway and increase in the p21Cip/WAF1 level. The ability of aspirin to activate AKT protein was observed also in presence of etoposide cotreatment. Our data indicate a new intracellular target of aspirin with potential clinical impact for treatment schedules involving both anticancer agents and aspirin in malignancies.

Nonsteroidal anti-inflammatory drugs in colorectal cancer: from prevention to therapy

In this review, we discuss the available experimental evidences supporting the chemopreventive efficacy of nonsteroidal anti-inflammatory drugs (NSAIDs) on colorectal cancer and the biological basis for their possible role as anticancer agents. Although the comprehension of the mechanisms underlying the effects of these drugs on colon cancer cells is incomplete, research efforts in identifying the biochemical pathway by which NSAIDs exert their chemopreventive effect have provided a rationale for the potential use of NSAIDs alone or in combination with conventional and experimental anticancer agents in the treatment of colorectal cancer. In this paper, we review three main issues: (i) the role of COX-2 in colon cancer; (ii) the common death pathways between NSAIDs and anticancer drugs; and (iii) the biological basis for the combination therapy with COX-2 selective inhibitors and new selective inhibitors of growth factor signal transduction pathways.