Aspirin enhances tumor necrosis factor-related apoptosis-inducing ligand-mediated apoptosis in hormone-refractory prostate cancer cells through survivin down-regulation

The multiple effects of aspirin in prostate cancer patients

Aspirin is a commonly used medication with anti-inflammatory and analgesic properties, and it is widely used to reduce the risk of ischaemic heart disease-related events and/or cerebrovascular accidents. However, there is also evidence from epidemiological and interventional studies to suggest that regular aspirin use can reduce the risk of prostate cancer development and progression, and can reduce the risk of disease recurrence following anti-prostate cancer therapy. Aspirin use in African-American men is associated with a reduced incidence of advanced PCa and reduced disease recurrence, and there is evidence from other studies of an association between regular aspirin use and decreased PCa-related mortality. The cyclooxygenase-2 enzyme inhibited by Aspirin and other NSAIDs, and which catalyses prostaglandin synthesis and mediates inflammation, is overexpressed in prostate cancer, therefore inhibition of cyclooxygenase-2 may have direct, and indirect, therapeutic effects. This review explores the evidence suggesting that aspirin use can modify prostate cancer biology and disease characteristics, and explores the potential mechanisms underpinning the observed associations between aspirin use and modification of prostate cancer risk. It also summarises the potential for adjuvant aspirin use to combine with other therapeutic approaches such as radical surgery and radiotherapy.

Trace of survivin in cancer

Survivin is one of the most cancer-specific proteins overexpressed in almost all malignancies, but is nearly undetectable in most normal tissues in adults. Functionally, as a member of the inhibitor of apoptosis family, survivin has been shown to inhibit apoptosis and increase proliferation. The antiapoptotic function of survivin seems to be related to its ability to inhibit caspases directly or indirectly. Furthermore, the role of survivin in cell cycle division control is related to its role in the chromosomal passenger complex. Consistent with its determining role in these processes, survivin plays a crucial role in cancer progression and cancer cell resistance to anticancer drugs and ionizing radiation. On the basis of these findings, recently survivin has been investigated intensively as an ideal tumor biomarker. Thus, multiple molecular approaches such as use of the RNA interfering technique, antisense oligonucleotides, ribozyme, and small molecule inhibitors have been used to downregulate survivin regulation and inhibit its biological function consequently. In this review, all these approaches are explained and other compounds that induced apoptosis in different cell lines through survivin inhibition are also reported.

Regular aspirin use and gene expression profiles in prostate cancer patients

PURPOSE

Pharmacoepidemiology studies suggest prognostic benefits of aspirin in prostate cancer. We hypothesized that aspirin induces transcriptional changes in tumors or normal prostate tissue.

METHODS

We analyzed the prostatic transcriptome from men diagnosed with prostate cancer during follow-up of the Physicians' Health Study 1 (PHS, n = 149), initially a randomized controlled trial of aspirin. Aspirin target genes were identified through systematic literature review and a drug target database. We compared target gene expression according to regular aspirin use at cancer diagnosis and used whole-transcriptome gene set enrichment analysis to identify gene sets associated with aspirin use. Results were validated in the Health Professionals Follow-up Study (HPFS, n = 254) and in Connectivity Map.

RESULTS

Of 12 target genes identified from prior studies and 540 genes from the drug target database, none were associated with aspirin use. Twenty-one gene sets were enriched in tumor tissue of aspirin users, 18 of which were clustered around ribosome function and translation. These gene sets were associated with exposure to cyclooxygenase inhibitors in Connectivity Map. Their association with cancer prognosis was U-shaped in both cohorts. No gene sets were enriched in normal tissue. In HPFS, neither the target genes nor the gene sets were associated with aspirin use.

CONCLUSIONS

Regular aspirin use may affect ribosome function in prostate tumors. Other putative target genes had similar expression in tumors from aspirin users and non-users. If results are corroborated by experimental studies, a potential benefit of aspirin may be limited to a subset of prostate cancer patients.

Survivin as a potential therapeutic target of acetylsalicylic acid in pituitary adenomas

Acetylsalicylic acid (ASA) is known as a cancer preventing agent, but there is no data available regarding the effect of ASA on pituitary cells.

We investigated 66 nonfunctioning (NFPA) and growth hormone (GH)-producing adenomas and 15 normal pituitary samples. Functional assays (cell viability, proliferation, flow cytometry cell cycle analysis, caspase-3 activation and DNA degradation) were applied to explore the effect of ASA, YM155 (survivin inhibitor), survivin-targeting siRNA and TNF-related apoptosis-inducing ligand (TRAIL) in RC-4B/C and GH3 cells. Pituitary adenoma xenografts were generated in immunocompromised mice.

We found that survivin was overexpressed and TRAIL was downregulated in NFPAs compared to normal pituitary tissue. ASA decreased proliferation but did not induce apoptosis in pituitary cells. Additionally, ASA treatment decreased cells in S phase and increased cells in G2/M phase of the cell cycle. Inhibition of survivin using an inhibitor or siRNA-mediated silencing reversed the ASA-induced growth inhibition partially. In addition, we also found survivin-independent effects of ASA on the cell cycle that were mediated through inhibition of cyclin A, cyclin dependent kinase 2 (CDK2) and phospho-CDK2. We also aimed to test the effect of acetylsalicylic acid in an animal model using RC-4 B/C cells, but in contrast to GH3 cells, RC-4 B/C cells failed to adhere and grow a xenograft.

We concluded that ASA inhibited the growth of pituitary adenoma cells. Survivin inhibition is a key mechanism explaining its antineoplastic effects. Our results suggest that inhibition of survivin with small molecules or ASA could serve as potential therapeutic agents in NFPA.

Prostate Cancer and Aspirin Use: Synopsis of the Proposed Molecular Mechanisms

Background: Prostate cancer (PCa) is a critical health burden, impacting the morbidity and mortality of millions of men around the world. Most of the patients with PCa have their disease at first sensitive to androgen deprivation treatments, but later they develop resistance to therapy and eventually die of metastatic castration-resistant prostate cancer (CRPC). Although the newly developed anti-androgen therapies are effectively alleviating symptoms and prolonging lives of patients, there are still no curable treatments for CRPC. Recently, statistical studies have shown that the chronic use of aspirin might be significantly associated with better outcomes in PCa patients. Through this review, we aim to identify the different proposed molecular mechanisms relating aspirin to the pathobiology of PCa neoplasms, with a major focus on basic research done in this context.

Methods: Articles were retrieved via online database searching of PubMed and MEDLINE between 1946 and September 2016. Keywords and combinations related to PCa and aspirin were used to perform the search. Abstracts of the articles were studied by two independent reviewers and then data extraction was performed on the relevant articles that met our review objectives.

Results: Aspirin, a non-steroidal anti-inflammatory drug (NSAID), affects the proliferation, apoptosis, resistance and metastasis of PCa cell lines, through both COX-dependent and COX-independent mechanisms. It also lowers levels of the PCa diagnostic marker prostate specific antigen (PSA), suggesting that clinicians need to at least be aware if their patients are using Aspirin chronically.

Conclusion: This review strongly warrants further consideration of the signaling cascades activated by aspirin, which may lead to new knowledge that might be applied to improve diagnosis, prognosis and treatment of PCa.

Co-acting gene networks predict TRAIL responsiveness of tumour cells with high accuracy

Background

Identification of differentially expressed genes from transcriptomic studies is one of the most common mechanisms to identify tumor biomarkers. This approach however is not well suited to identify interaction between genes whose protein products potentially influence each other, which limits its power to identify molecular wiring of tumour cells dictating response to a drug. Due to the fact that signal transduction pathways are not linear and highly interlinked, the biological response they drive may be better described by the relative amount of their components and their functional relationships than by their individual, absolute expression.

Results

Gene expression microarray data for 109 tumor cell lines with known sensitivity to the death ligand cytokine tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) was used to identify genes with potential functional relationships determining responsiveness to TRAIL-induced apoptosis. The machine learning technique Random Forest in the statistical environment “R” with backward elimination was used to identify the key predictors of TRAIL sensitivity and differentially expressed genes were identified using the software GeneSpring. Gene co-regulation and statistical interaction was assessed with q-order partial correlation analysis and non-rejection rate. Biological (functional) interactions amongst the co-acting genes were studied with Ingenuity network analysis. Prediction accuracy was assessed by calculating the area under the receiver operator curve using an independent dataset. We show that the gene panel identified could predict TRAIL-sensitivity with a very high degree of sensitivity and specificity (AUC = 0 · 84). The genes in the panel are co-regulated and at least 40% of them functionally interact in signal transduction pathways that regulate cell death and cell survival, cellular differentiation and morphogenesis. Importantly, only 12% of the TRAIL-predictor genes were differentially expressed highlighting the importance of functional interactions in predicting the biological response.

Conclusions

The advantage of co-acting gene clusters is that this analysis does not depend on differential expression and is able to incorporate direct- and indirect gene interactions as well as tissue- and cell-specific characteristics. This approach (1) identified a descriptor of TRAIL sensitivity which performs significantly better as a predictor of TRAIL sensitivity than any previously reported gene signatures, (2) identified potential novel regulators of TRAIL-responsiveness and (3) provided a systematic view highlighting fundamental differences between the molecular wiring of sensitive and resistant cell types.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-1144) contains supplementary material, which is available to authorized users.

Aspirin suppresses growth of human gastric carcinoma cell by inhibiting survivin expression

Regular use of aspirin (ASA) could reduce the risk of gastric cancer although the precise mechanism remains unclear. Down-regulation of survivin may be one of the cyclooxygenase-independent mechanisms whereby ASA induces apoptosis of gastric cancer cell. In this study, we investigated the effect of ASA on the growth, apoptosis and survivin expression of gastric cancer cell line SGC7901. The survival of cells treated with 3.0 and 10.0 mmol/L ASA for 24 h was decreased by 44.6% and 88.5%, respectively. ASA at 3.0 mmol/L inhibited the viability of SGC7901 cells in a time-dependent manner. Apoptosis analysis showed similar results with MTT assay. ASA at 3.0 and 10.0 mmol/L decreased the mRNA transcript levels of survivin and reduced survivin protein levels in SGC7901 cells also in a time-dependent manner. Our findings indicated that ASA inhibited the proliferation of SGC7901 by suppressing survivin at both the transcriptional and translational level.

Aspirin overcomes Navitoclax-resistance in hepatocellular carcinoma cells through suppression of Mcl-1

Small-molecule Bcl-2/Bcl-xL inhibitor Navitoclax represents a promising cancer therapeutic since preclinical and clinical studies with Navitoclax have demonstrated strong anticancer activity in several types of cancers. However, because Navitoclax has a low binding affinity to Mcl-1, anticancer activity by Navitoclax is often attenuated by the elevated expression of Mcl-1 in hepatocellular carcinoma (HCC) and other cancers, posing a serious problem for its potential clinical utilities. Therefore, approaches that suppress the expression of Mcl-1 are urgently needed to overcome Navitoclax-resistance in these cancers. Here, we reported that aspirin markedly suppressed Mcl-1 expression, and significantly enhanced Navitoclax-mediated cell viability inhibition and apoptosis induction in HCC cells. We further showed that aspirin robustly enhanced Navitoclax-triggered cytosolic cytochrome c release, activation of initiator caspase-9 and effector caspase-3, and cleavage of PARP. Importantly, the cell death induction by the combination could be rescued by a cell-permeable caspase-9 inhibitor Z-LEHD-FMK, indicative of an indispensable role of mitochondrial apoptosis pathway during the combination effect. Taken together, our study suggests that aspirin can be used to enhance Navitoclax-mediated anticancer activity via suppression of Mcl-1. Since aspirin is one of the most commonly used medicines, our findings therefore have translational impacts on Navitoclax-based therapy for HCC.

Inducing apoptosis in rolling cancer cells: a combined therapy with aspirin and immobilized TRAIL and E-selectin

Though metastasis is considered an inefficient process, over 90% of cancer related deaths are attributed to the formation of secondary tumors. Thus, eliminating circulating cancer cells could lead to improved patient survival. This study was aimed at exploiting the interactions of cancer cells with selectins under flow to selectively kill captured colon cancer cells. Microtubes functionalized with E-selectin and TRAIL were perfused with colon cancer cell line Colo205 either treated with 1 mM aspirin or untreated for 1 or 2 h. Cells were collected from the microtube and analyzed by flow cytometry. Aspirin treatment alone killed only 3% cells in culture. A 95% difference in the number of cells killed between control and TRAIL + ES surfaces was seen when aspirin treated cells were perfused over the functionalized surface for 2 h. We have demonstrated a novel biomimetic method to capture and neutralize cancer cells in flow, thus reducing the chances for the formation of secondary tumors.

Methyl jasmonate down-regulates survivin expression and sensitizes colon carcinoma cells towards TRAIL-induced cytotoxicity

BACKGROUND AND PURPOSE

Methyl jasmonate (MJ) is a plant stress hormone with selective cytotoxic anti-cancer activities. The TNF-related apoptosis-inducing ligand (TRAIL) death pathway is an attractive target for cancer therapy. Although TRAIL receptors are specifically expressed in primary cancer cells and cancer cell lines, many types of cancer cells remain resistant to TRAIL-induced cytotoxicity. Here we have assessed a possible synergy between MJ and TRAIL cytotoxicity in colorectal cancer (CRC) cell lines.

EXPERIMENTAL APPROACH

CRC cell lines were pre-incubated with sub-cytotoxic concentrations of MJ followed by TRAIL administration. Cell death was determined by XTT assay and microscopy. Cytochrome c release, caspase cleavage, TRAIL-associated factors, X-linked inhibitor of apoptosis (XIAP) and survivin protein levels were detected by immunoblotting. Survivin transcription was examined by RT-PCR.

KEY RESULTS

Pre-treatment with MJ resulted in increased TRAIL-induced apoptotic cell death, increased cytochrome c release and caspase cleavage. TNFRSF10A, TNFRSF10B, TNFRSF10D, Fas-associated death domain and cellular FLICE-like inhibitory protein remained unchanged during MJ-induced TRAIL sensitization, whereas MJ induced a significant decrease in survivin protein levels. Overexpression of survivin prevented MJ-induced TRAIL cytotoxicity, implying a role for survivin in MJ-induced TRAIL sensitization. MJ decreased survivin mRNA indicating that MJ may affect survivin transcription. In a β-catenin/transcription factor (TCF)-dependent luciferase activity assay, MJ decreased TCF-dependent transcriptional activity.

CONCLUSION AND IMPLICATIONS

MJ, at sub-cytotoxic levels, sensitized CRC cells to TRAIL-induced apoptosis. Thus, combinations of MJ and TRAIL, both selective anti-cancer agents, have potential as novel treatments for CRC.

The effect of demographic and clinical factors on the relationship between BMI and PSA levels

INTRODUCTION

Studies have reported lower prostate specific antigen (PSA) levels in men with a higher body mass index (BMI). Additional factors such as diabetes mellitus, benign prostatic hyperplasia (BPH) and certain medications may also affect PSA levels and confound the PSA-BMI association. In this study we evaluated the potential confounding effect of these factors on the obesity-PSA relationship and evaluated the association between these factors and PSA level.

METHODS

The study cohort consisted of 770 population-based controls without a history of prostate cancer (PCa) who participated in a prior PCa study. Demographic, anthropometric, and medical history data were obtained, and PSA level was determined from blood drawn at the time of interview. Linear regression was performed to evaluate the PSA-BMI relationship, adjusting for potential confounders. Finally, a forward stepwise algorithm was used to determine which factors were independently associated with PSA values.

RESULTS

With increase in BMI (<25, 25-29, ≥30), the geometric mean PSA level declined (1.18, 1.13, and 0.94, respectively); obese men had a 17% (95% CI 0.70-0.99) lower age-adjusted PSA level compared to normal weight men. However, this relationship was non-significant (P = 0.17) in the multivariate model. Independent predictors of PSA level included age (β = 1.03, 95% CI 1.02-1.04), history of BPH (β = 1.48, 95% CI 1.27-1.72), current statin (β = 0.85, 95% CI 0.74-0.98), and NSAID use (β = 0.84, 95% CI 0.72-0.98).

CONCLUSION

The relationship between obesity and PSA is confounded by a number of factors, which likely explain the observed inverse association previously reported. These results should help in interpreting PSA values in men screened for PCa.

Effects of simvastatin, acetylsalicylic acid, and rosiglitazone on proliferation of normal and cancerous prostate epithelial cells at therapeutic concentrations

BACKGROUND

Non-steroidal anti-inflammatory drugs and cholesterol-lowering statins have been reported to inhibit prostate cancer cell growth suggesting their chemopreventive potential within the prostate. However, the effect has been demonstrated only with advanced prostate cancer cell lines and with drug concentrations above the clinical therapeutic range. In this study we compared the effect of therapeutic concentrations of acetylsalicylic acid, simvastatin and rosiglitazone on the growth of a set of prostatic primary cultures and various prostate epithelial cell lines.

METHODS

Two primary epithelial cell lines isolated from surgical resecates of normal prostate tissue (P96E, P97E), a primary cell line isolated from untreated prostate carcinoma (ESTO1), two transformed prostate epithelial cell lines (PWR1-E, RWPE-1) and advanced cancer cell lines LNCaP and VCaP were used in the study. Cells were treated for seven days with therapeutic concentrations of acetylsalisylic acid, simvastatin, rosiglitazone or their combination. Cellular growth rate was measured by crystal violet staining method.

RESULTS

Acetylsalicylic acid (0.5 mM) and simvastatin (10 nM) inhibited the growth of prostate epithelial cells of normal and primary cancer origin, whereas advanced cancer cell lines were resistant to the effect. Rosiglitazone at the therapeutic level of 1 microM did not reduce the growth of any cell type studied.

CONCLUSIONS

Our results demonstrate that acetylsalicylic acid and simvastatin inhibit prostate epithelial cell growth at clinically relevant doses. This should be acknowledged when designing possible prostate cancer chemopreventive trials.

Studies on search for bioactive natural products targeting TRAIL signaling leading to tumor cell apoptosis

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) induces apoptosis in many transformed cells but not in normal cells and, hence, has been expected as a new anticancer strategy. During our studies on search for bioactive natural products from various natural resources such as plants and microorganisms, we recently identified several natural products which exhibited activities related to TRAIL signaling. Dimeric sesquiterpenoids isolated from Zingiberaceous plant, Curcuma parviflora, showed enhancement activity of gene expression of TRAIL-receptor and TRAIL-receptor protein level. Several new isoflavone natural products, named brandisianins, were isolated from Leguminosaeous plant, Millettia brandisiana, by our screening study targeting TRAIL-receptor expression enhancement activity. A dihydroflavonol (BB1) that was extracted from Compositaeous plant, Blumea balsamifera, and fuligocandin B, a new anthranilylproline-indole alkaloid isolated from myxomycete were found to exhibit reversal effect of TRAIL resistance activity.

Aspirin sensitizes cancer cells to TRAIL-induced apoptosis by reducing survivin levels

PURPOSE

Although tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and agonistic antibodies targeting its receptors are promising cancer therapies because of their tumor selectivity, many tumors are resistant to TRAIL-based therapies. We examined whether the nonsteroidal anti-inflammatory drug aspirin sensitized cancer cells to TRAIL agonists in vitro and in vivo and investigated the underlying mechanism.

EXPERIMENTAL DESIGN

The effects of aspirin on sensitivity to TRAIL agonists and expression of apoptosis regulators was determined in human breast cancer cell lines and xenograft tumors. The specific role of survivin depletion in the TRAIL-sensitizing effects of aspirin was determined by silencing survivin.

RESULTS

Aspirin sensitized human breast cancer cells, but not untransformed human mammary epithelial cells, to TRAIL-induced caspase activation and apoptosis by a cyclooxygenase-2-independent mechanism. Aspirin also sensitized breast cancer cells to apoptosis induced by a human agonistic TRAIL receptor-2 monoclonal antibody (lexatumumab). Aspirin treatment led to G1 cell cycle arrest and a robust reduction in the levels of the antiapoptotic protein survivin by inducing its proteasomal degradation, but did not affect the levels of many other apoptosis regulators. Silencing survivin with small interfering RNAs sensitized breast cancer cells to TRAIL-induced apoptosis, underscoring the functional role of survivin depletion in the TRAIL-sensitizing actions of aspirin. Moreover, aspirin acted synergistically with TRAIL to promote apoptosis and reduce tumor burden in an orthotopic breast cancer xenograft model.

CONCLUSIONS

Aspirin sensitizes transformed breast epithelial cells to TRAIL-based therapies in vitro and in vivo by a novel mechanism involving survivin depletion. These findings provide the first in vivo evidence for the therapeutic utility of this combination.