Regular Aspirin Intake Research Articles

Biochemical aspirin resistance in acute stroke patients and its association with clinical factors: aprospective pilot study.

Aspirin is still widely used in treatment and prevention of cardiovascular diseases. To predict which patients cannot benefit from aspirin due to aspirin resistance remains agreat clinical challenge. Fifty one acute stroke/transient ischemic attack (TIA) patients (ASG) with ahistory of regular aspirin intake for the previous 7 days or more were included to the study within 24 hours of symptoms onset. Twenty nine patients admitted to our department for other reasons were the controls (CG). Each patient underwent routine blood tests (white blood cells, platelets, total cholesterol, C-reactive protein) and additional blood test: glycated haemoglobin (HbA1c), insulin, and N-terminal prohormone of brain natriuretic peptide (NT-proBNP). Biochemical aspirin resistance was measured using the VerifyNow Aspirin platelet function analyzer. There were 9 aspirin resistance patients in ASG (17.5%) and 3 in CG (10.3%) (p = 0.38). There were no differences in either age or gender between those groups. Twelve aspirin-resistant patients differed from aspirin nonresistant patients in age, NT-proBNP and total cholesterol levels (univariate model, p = 0.004, 0.04, 0.02, respectively). In amultivariate model patients aged 76 years and more would likely to be aspirin resistant with odds ratio = 9 (95% confidence interval: 1-78). Patients aged 76 and more can be more likely aspirin resistant than younger patients. We believe that especially in the elderly with congestive heart failure there is astrong need for further investigations in this field, including searching for alternative antiplatelet therapies.

Antiplatelet Therapy Improves the Prognosis of Patients with Hepatocellular Carcinoma.

Simple SummaryAntiplatelet therapy shows antitumor effect in several types of cancers. In liver disease, antiplatelet therapy reduces liver fibrosis and occurrence of HCC. However, the effect after diagnosis of hepatocellular carcinoma is still unknown. Therefore, we aimed to clarify the effects of antiplatelet therapy for HCC patients in this study. We compared patients with and without antiplatelet therapy in overall survival, liver-related death, tumor progression, Child-Pugh deterioration and bleeding. Our results suggested that antiplatelet therapy had antitumor effect, liver protective effect and safety. Therefore, patients with antiplatelet therapy could reduce liver-related death and improve overall survival.Aims: Antiplatelet therapy has been reported to reduce liver fibrosis and hepatocellular carcinoma (HCC), and has exhibited antitumor properties in other cancers. However, the effects of antiplatelet therapy after diagnosis of HCC are unknown. We investigated the effects of antiplatelet therapy on prognosis, tumor progression, liver function and safety in HCC patients. Methods: We retrospectively analyzed 772 HCC patients. Antiplatelet therapy was defined as the regular intake of aspirin or clopidogrel from HCC diagnosis through to an endpoint of either overall survival (OS) or liver-related death. Overall survival, liver-related death, tumor progression, Child–Pugh deterioration and hemorrhage were analyzed for patients who either had or had not undertaken antiplatelet therapy. Results: The numbers of patients who did and did not undertake antiplatelet therapy were 111 and 661, respectively. Patients who undertook antiplatelet therapy were older and had better liver function at diagnosis. Antiplatelet therapy resulted in significant improvements in OS (p < 0.01) and lower risk of liver-related death (p < 0.01). Multivariate Cox regression analysis revealed that antiplatelet therapy had a significant negative association with liver-related death (hazard ratio (HR): 0.64, 95% confidence interval (CI): 0.44–0.93, p = 0.02). In patients who underwent transcatheter arterial chemoembolization (TACE) as the first treatment, antiplatelet therapy prevented tumor progression (p < 0.01) and Child–Pugh deterioration (p < 0.01). Antiplatelet therapy did not increase the risk of hemorrhagic events. Conclusions: Antiplatelet therapy reduced liver-related death and improved OS safely in HCC patients.

Association between lifestyle-related factors and colorectal adenoma

Objective: To explore the association between lifestyle-related factors and colorectal adenoma. Methods: Based on the Screening Project of Early Diagnosis and Treatment of Colorectal Cancer in Jiashan county Zhejiang province, from August 2012 to March 2018, information gathered through records on questionnaire and colonoscopic diagnosis were collected from participants with positive results during the primary screening stage. According to the findings of colonoscopy, 11 232 controls without any colorectal diseases and 3 895 cases with colorectal adenoma were included in the study. Multivariate logistic regression models were used to analyze the association between lifestyle-related factors and colorectal adenoma. Results: After adjusting for possible confounding factors, results from multivariate logistic regression analysis showed that smoking, alcohol drinking and obesity were positively related to the risk of colorectal adenoma, with ORs (95%CIs) as 1.38 (1.24-1.54), 1.37 (1.24-1.51) and 1.38 (1.20-1.59) respectively. However, regular aspirin intake was negatively related with the risk of colorectal adenoma (OR=0.65, 95%CI: 0.53-0.80). After stratified by sex and age, data showed that the associations between smoking, alcohol drinking and colorectal adenoma were statistically significant in males, and the association between regular aspirin intake and colorectal adenoma was also statistically significant in older participants (aged 60 years and older). Conclusion: Smoking, alcohol drinking, regular aspirin intake and obesity were associated with colorectal adenoma.

Regular aspirin intake and prognosis of TxN2-3M0 nasopharyngeal carcinoma: A cohort study based on propensity score matching

Distant metastasis is the leading cause of death in patients with N2-3 nasopharyngeal carcinoma (NPC). And aspirin is found to reduce metastasis and improve prognosis in some other malignancies, such as colorectal cancer. This study aimed to evaluate the clinical value of regular aspirin intake (RAI) in N2-3 NPC treated with standard chemoradiotherapy. Totally 2064 patients diagnosed with TxN2-3M0 NPC from Jan. 2008 to Dec. 2015 and treated with neoadjuvant chemotherapy followed by concurrent chemoradiotherapy were involved. According to RAI, these patients were divided into 2 groups between which a propensity score matching was made, with a ratio of 1:3 and a series of clinical characteristics (age, gender, T stage, N stage and EBV DNA) as covariates. Then survivals and acute toxicities were compared in the 464 matched patients. RAI appeared to bring better overall (87.7% vs. 79.6%, P=0.031), metastasis-free (87.8% vs. 76.5%, P=0.017) and disease-free (85.9% vs. 75.5%, P=0.033) survivals. It simultaneously increased total incidences of myelosuppression (55.2% vs. 32.2%, P<0.001), oral mucositis (60.3% vs. 38.2%, P<0.001), cervical dermatitis (60.3% vs. 38.5%, P<0.001) and xerostomia (49.1% vs. 33.3%, P=0.002). But RAI failed to affect incidence of any grade 3/4 toxicity. Post-diagnosis RAI might be a tolerable approach to control distant metastasis and provide survival benefit for N2-3 NPC in combination with standard chemoradiotherapy.

Influence of regular aspirin intake on PSA values, prostate cancer incidence and overall survival in a prospective screening trial (ERSPC Aarau).

To analyze the influence of aspirin (ASA) intake on PSA values and prostate cancer (PCa) development in a prospective screening study cohort. 4314 men from the Swiss section of the European Randomized Study of Screening for Prostate Cancer (ERSPC) were included. A transrectal prostate biopsy was performed in men with a PSA level ≥ 3ng/ml. Mortality data were obtained through registry linkages. PCa incidence and grade, total PSA, free-to-total PSA and overall survival were compared between ASA users and non-users. Median follow-up time was 9.6years. In 789 men (18.3%) using aspirin [ASA +], the overall PCa incidence was significantly lower (6.8% vs. 9.6%, p = 0.015), but the multivariate Cox regression analysis showed no significant decrease in risk of PCa diagnosis (HR 0.84, p = 0.297). Total PSA values were significantly lower in ASA users for both baseline (1.6 vs. 1.8ng/ml, p = 0.007) and follow-up visits (1.75 vs. 2.1ng/ml, p < 0.001). Multivariate Cox regression analysis predicted significantly higher overall mortality risk among ASA users (HR 1.46, p = 0.009). In our study population, PCa incidence was significantly reduced among patients on aspirin. While we did not observe a statistically significant PCa risk reduction during the follow-up period, we found lower PSA values among ASA users compared to non-users, with a more distinct difference after 4years of ASA intake, suggesting a cumulative effect and a potential protective association between regular ASA intake and PCa development. As for clinical practice, lowering PSA cutoff values by 0.4ng/ml could be considered in long-term ASA users to avoid a potential bias towards delayed PCa detection.

1131 - Influence of regular aspirin intake on PSA values, prostate cancer incidence and overall survival in a prospective screening trial (ERSPC Aarau)

1131 - Influence of regular aspirin intake on PSA values, prostate cancer incidence and overall survival in a prospective screening trial (ERSPC Aarau)

Use of non-steroidal anti-inflammatory drugs, aspirin and the risk of depression: The “Seguimiento Universidad de Navarra (SUN)” cohort

BackgroundThe potential effect of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) to prevent depression remains largely unknown, in spite of the implication of inflammation in depression. This study aimed to investigate whether the habitual intake of aspirin and other NSAIDs was prospectively associated with a reduction in the observed incidence of depression. MethodsA dynamic cohort including 22,564 Spanish university graduates (mean age: 37 years) initially free of depression was followed during an average of 8.7 years. Exposure to NSAIDs was assessed with specific repeated questionnaires throughout follow-up, starting in the 2-year follow-up questionnaire. Incident cases of depression were defined as either a new validated medical diagnosis of depression or reporting the initiation of habitual use of antidepressants. ResultsWe identified 772 incident cases of depression. Regular intake of aspirin and other NSAIDs was not associated with depression risk. Only in secondary sensitivity analyses using a definition of the outcome with higher specificity (a validated medical diagnosis of depression), an inverse association of aspirin with depression was found [HR (95%CI): 0.20 (0.04–0.87)]. However, these results were non-significant after adjustment for multiple testing. LimitationsA possible underestimation of incident depression and a limited ability to detect all possible residual confounding. ConclusionsRegular use of NSAIDs was not associated with the incidence of depression. Further longitudinal controlled studies are necessary to clarify a potential role of aspirin use in depression risk.

Aspirin Resistance in Acute Ischemic Non-cardioembolic Stroke: Frequency and Clinical Study

Platelet activation in cerebrovascular diseases is associated with recurrent stroke and death. Aspirin is an effective antiplatelet agent, exhibiting its action by irreversibly inhibiting platelet cyclooxygenase-1 enzyme, thus preventing the production of thromboxane A2 (TXA2). Objectives: The study is designed to find the frequency of aspirin resistance (AR) among acute ischemic non-cardioembolic stroke patients, and to assess the clinical picture of those patients. Mehtods: This study included 80 patients39 males and 41 females (mean age: 63 years 11.8 SD), they were diagnosed clinically and via brain imaging within 24 hours following stroke onset. They were given non coated, same preparation of aspirin 150 mg/day regularly and under observation, Low molecular weight heparin 40 mg per day. The patients were followed up clinically and via GCS, NIHSS and APACHEII scales. Assessment of aspirin resistance was done one week after regular aspirin intake through: bleeding time, coagulation time and assessment of thromboxaneA2 level in serum using ELIZA. The patients were classified into two groups aspirin resistant (AR) and aspirin sensitive (AS) and the data were compared in both. Results: AR patients represented 33.75% of our sample. History of TIAs and stroke was more prevalent among them. In AR patients: the followings were also more frequent: more affection of consciousness, power, sensation, language, coordination, vertigo, vomiting, large size of cerebral infarcts, temporal and parietal infarcts. There were high significant negative correlation between GCS and TXA2level and between the later and changes in bleeding time in the first day and 7 days following stroke onset. On the other hand there were high positive correlation between TXA2 level and NIHSS score and infarct size. Coclusion: AR was frequent among ischemic non-cardioembolic stroke and they were associated with history of TIAs and previous strokes, and presented with more severe clinical presentation and larger size of cerebral infarcts, So early identification of AR prevents its fruitless use.

Regular aspirin use and the risk of lethal prostate cancer in the Physicians' Health Study.

306 Background: Aspirin exerts chemopreventive effects against several malignancies. An inverse association between regular aspirin intake and advanced prostate cancer is suggested by previous reports, but potential effects on lethal prostate cancer have not been characterized. Methods: The study population comprised 22,071 male physicians enrolled in the prospective Physicians' Health Study followed from 1982-2009. We evaluated the relationship between regular aspirin intake ( &gt; 3 tablets per week) and lethal prostate cancer (metastases or prostate cancer death). Secondary outcomes included the incidence of total, high-grade (Gleason 8-10), and advanced (T3b-T4 or N1 or M1) cancers. Cox proportional hazards models estimated age- and multivariate-adjusted hazard ratios (HR) for the incidence of primary and secondary outcomes and survival among participants with prostate cancer. Results: Over 27 years of follow-up (533,261 person-years), 3,183 men were diagnosed with prostate cancer, of whom 402 developed lethal disease. Decreased multivariate-adjusted risks of lethal prostate cancer were observed for regular aspirin users (HR: 0.67, 95%CI: 0.55-0.82). Recent regular use (within 12 months) was protective, with effects diminishing with time since last regular use (p for trend = 0.007). Among men with prostate cancer, regular aspirin use after diagnosis was associated with decreased prostate cancer mortality (HR: 0.79, 95%CI: 0.64-0.98), whereas pre-diagnostic use did not confer a measurable benefit. Regular aspirin use was not significantly associated with the incidence of total, high-grade, or advanced cancers. Conclusions: Regular aspirin use was associated with a decreased risk of lethal prostate cancer in this cohort of American physicians. An inhibitory effect of regular aspirin use on prostate cancer progression is suggested.

Blood levels of serotonin are specifically correlated with plasma lysophosphatidylserine among the glycero-lysophospholipids

BackgroundsGlycero-lysophospholipids (glycero-LPLs), which are known to exert potent biological activities, have been demonstrated to be secreted from activated platelets in vitro; however, their association with platelet activation in vivo has not been yet elucidated. In this study, we investigated the correlations between the blood levels of each glycero-LPL and serotonin, a biomarker of platelet activation, in human subjects to elucidate the involvement of platelet activation in glycero-LPLs in vivo. Methods and ResultsWe measured the plasma serotonin levels in 141 consecutive patients undergoing coronary angiography (acute coronary syndrome, n=38; stable angina pectoris, n=71; angiographically normal coronary arteries, n=32) and investigated the correlations between the plasma levels of serotonin and glycero-LPLs. The results revealed the existence of a specific and significant association between the plasma serotonin and plasma lysophosphatidylserine (LysoPS) levels. On the contrary, regular aspirin intake failed to affect the plasma LysoPS levels despite the fact that the plasma lysophosphatidic acid, lysophosphatidylethanolamine, lysophosphatidylglycerol, and lysophosphatidylinositol levels were lower in those who had taken aspirin regularly. ConclusionWe found a specific positive correlation between the blood levels of serotonin and LysoPS, a new lipid mediator. Thus, LysoPS might be specifically involved in strong platelet activation, which is associated with the release of serotonin. General SignificanceOur present results suggest the possible involvement of LysoPS in the pathogenesis of atherosclerotic diseases.

Prevalence of aspirin resistance in Asian‐Indian patients with stable coronary artery disease

To evaluate the prevalence of pharmacological resistance to aspirin therapy by measuring platelet functions using the technique of light transmission aggregometry. Aspirin is the cornerstone of antiplatelet therapy in patients with coronary artery disease (CAD). However, a substantial proportion of patients manifest breakthrough thrombotic events despite regular intake of aspirin suggesting therapeutic resistance to aspirin. We prospectively studied 126 patients with stable coronary artery disease at a tertiary center, who were recruited after ensuring compliance with a single formulation of aspirin (enteric coated aspirin 150 mg). Platelet aggregation was measured using light transmission aggregometry with ADP (10 µM) and Arachidonic acid (0.5 mg/mL). Pharmacological aspirin resistance was defined as the combined demonstration of mean platelet aggregation of ≥70% with 10 µM ADP and a mean aggregation of ≥20% with 0.5 mg/mL A.A. Patients satisfying either one of the above criteria were defined as semi-responders. Patients satisfying neither criterion were defined as "aspirin responders". Out of 126 patients with stable CAD, 64 % were responders, 36% were non responders (semi-responders = 34% and resistant = 2%). Of the laboratory parameters, only the total leukocyte count was significantly associated with the presence of aspirin resistance (P < 0.03). Pharmacological resistance to aspirin is noted in 36% (semi-responders = 34% and resistant = 2%) of Asian Indian patients with stable CAD. Long-term follow up of these patients will assist in determining the clinical importance of this phenomenon. © 2014 Wiley Periodicals, Inc.

Abstract 3501: Aspirin modulates oncogene expression in hct 116 colon cancer cells

Abstract Aspirin is a 100 year old Non-steroidal anti-inflammatory drug (NSAID). Beside its use a cardio-protective agent, it is also used for treatment of headache, fever, and inflammation. Many studies have shown that regular intake of aspirin for 5 years or more reduces the risk of colon, breast, prostate, lung and skin cancers. However, mechanism for such actions is not very well understood. Since transformation of a normal cell to cancer cell often involves mutation and activation of proto-oncogene, we initiated this research to understand if aspirin modulates the level of oncogene products. In this study we focused on three different oncogenes; c-FOS, c-JUN and c-RAF. c-FOS and c-JUN are transcription factors, they form a heterodimer called Activator protein (AP-1) transcription factor and regulate the expression of other genes. We observed that, in serum starved HCT-116 colon cancer cells Aspirin and Salicylic acid inhibited serum induced c-FOS protein expression, however, levels of c-JUN protein were not inhibited. In fact Aspirin and Salicylic acid increased c-JUN levels marginally over the serum induced levels at all time points examined. Exposure of cells to Aspirin and Salicylic acid inhibited c-RAF levels in a concentration dependent fashion. Inhibition was observed at physiologically achieved concentration of 250 -500 micro molar Salicylic acid suggesting that Aspirin may mediate its effects through the formation of Salicylic acid. We are currently investigating how inhibition of c-RAF levels by Aspirin and Salicylic acid affects downstream signaling molecules such as p42/p44 MAP kinases. Modulation of proto oncogenes by Aspirin may represent an important pathway by which Aspirin may mediate its anti-cancer effects. Citation Format: Rakesh Dachineni, Goqiang Ai, Jayarama B. Gunaje. Aspirin modulates oncogene expression in hct 116 colon cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3501. doi:10.1158/1538-7445.AM2014-3501

Differential Effects of Aspirin Before and After Diagnosis of Colorectal Cancer

ALTHOUGH MORBIDITY AND MORTALITY FROM COLOrectal cancer have steadily decreased over the past 3 decades, colorectal cancer remains the third most common form of cancer and the third most common cause of cancer death in the United States. Early disease detection through increases in screening that can identify and allow removal of precancerous polyps is thought to be the major reason for the decrease in colorectal cancer incidence. Additionally, new chemotherapy regimens and targeted therapies have improved the outcome of patients with locally advanced and metastatic colorectal cancer. Several risk factors for colorectal cancer have been identified in epidemiologic studies. These include obesity, 50 years or older, personal and family history of polyps or colorectal cancer, diabetes, and black race/ethnicity. Similarly, several factors are associated with decreased colorectal cancer risk. For example, observational data suggest that physical activity and increased dietary calcium intake are associated with decreased risk of colorectal cancer. There are no generally accepted chemopreventive recommendations for individuals at average risk of colorectal cancer but several medications have been shown to have a cancer preventive effect in averageand high-risk populations. The most compelling evidence comes from observational and interventional trials showing that aspirin is protective against the development of colorectal cancer, colorectal cancer metastases, and disease recurrence after diagnosis of the disease. In addition, the protective effect of aspirin also has been demonstrated in patients with hereditary colorectal cancer. The mechanism of action of the colorectal cancer chemopreventive and anticancer effects of aspirin is not fully understood, but it has been attributed to the antiinflammatory effects of the drug, specifically inhibition of prostaglandin-endoperoxide synthase 2 (PTGS2, formerly named cyclooxygenase 2 or COX-2). PTGS2 is the ratelimiting step for the conversion of arachidonic acid to prostaglandins, and it is overexpressed in the majority of colorectal cancers. In the past few years, several studies have attempted to dissect aspirin’s mechanism of action with respect to colorectal cancer development and progression to identify which subtypes of colorectal cancer aspirin most effectively prevents both before and after diagnosis. In 2009, Chan et al demonstrated that regular aspirin intake after diagnosis of colorectal cancer in patients whose primary tumors overexpressed PTGS2 as assessed by immunohistochemistry was associated with a 60% decreased risk of colorectal cancer– specific mortality. In contrast, there was no association between aspirin use and lower mortality risk among patients whose primary tumors had weak or absent PTGS2 expression. In 2012, Liao et al tested the hypothesis that mutations in the PIK3CA gene, one of the most commonly mutated genes in colorectal cancer, might influence the effect of aspirin in patients with a diagnosis of colorectal cancer. This study showed that the decreased risk of colorectal cancer recurrence associated with the use of aspirin was restricted to patients with tumors harboring a mutated PIK3CA gene. PIK3CA belongs to the PI3K-AKT signaling pathway, which is inappropriately activated in many cancers, including colorectal cancer. The BRAF gene belongs to the RAS-RAF-MEK-ERK signaling pathway and is mutated in approximately 14% of colorectal cancers leading to uncontrolled activation of the pathway. Furthermore, there is evidence that somatically acquired mutations of the BRAF gene portend a poor prognosis. Whether the BRAF gene acts as a mediator of the effect of aspirin prior to and after diagnosis of colorectal cancer is unknown. Importantly, both pathways are directly activated by the epidermal growth factor receptor (EGFR), an established therapeutic target in advanced colorectal cancer. In this issue of JAMA, Nishihara et al analyzed tumors from 1226 patients with a diagnosis of colorectal cancer for mutations within the BRAF gene. When compared to nonusers, aspirin users had a 27% lower risk of having tumors with an intact BRAF gene. In contrast, aspirin use was not associated with any change in risk for BRAF-mutated tumors. Use of aspirin after diagnosis of colorectal cancer did not modify the outcome for patients with either BRAFmutated or BRAF–wild-type tumors.

Acetylsalicylsäure und Prävention kolorektaler Karzinome

Observational and some randomized clinical trials suggest that aspirin protects from occurrence and progression of colorectal neoplasias (adenomas, carcinomas). However, there are still open questions, regarding the benefit/risk ratio (bleedings) as well as dosage and duration of treatment during the probably long-term medication, before stringent recommendations regarding clinical use of aspirin can be made. Specifically, there is currently no generally accepted mode of action or molecular target of aspirin, though a relationship to tumor-associated enhanced PGE2 levels in the affected mucosa is likely. Regular daily intake of aspirin in antiplatelet doses of 100mg appears to be sufficient in responding persons. If this is confirmed in prospective randomized trials that are currently underway, this might add to the prophylactic use of aspirin and would suggest a pharmacological relationship to inhibition of COX-1 mediated prostaglandin/thromboxane biosynthesis as a common primary target for both cardiocoronary and antineoplastic prophylaxis. Prophylactic aspirin use might then add to an undoubtedly important healthy lifestyle including appropriate diet.

Aspirin in the aetiology of Crohn’s disease and ulcerative colitis: a European prospective cohort study

Aspirin has detrimental effects on the gastrointestinal tract mucosa and may play a role in the aetiology of inflammatory bowel disease. To investigate if the regular use of aspirin is associated with the development of Crohn's disease (CD) and ulcerative colitis (UC) using, for the first time, a prospective cohort study design. A total of 135,780 men and women in Europe, aged 30-74years, were recruited into the European Prospective Investigation into Cancer and Nutrition study. Participants completed questionnaires at baseline detailing their regular aspirin use and were then followed up to identify those who developed either incident CD or UC. Each case was matched with four controls and odds ratios (OR) were calculated, adjusting for cigarette smoking. Potential interactions between aspirin and smoking were assessed. A total of 35 participants developed CD and a further 84 were diagnosed with UC. Regular aspirin intake was positively associated with the risk of developing CD (OR=6.14, 95% CI=1.76-21.35). In those who took aspirin and smoked there was no detectable increased risk of CD (OR=0.30, 95% CI=0.03-3.08). No association was found between regular aspirin use and UC (OR=1.29, 95% CI=0.67-2.46). A strong positive association between regular aspirin use and CD, but not UC, was observed. The data suggest that regular aspirin use should be measured in epidemiological work on CD. If such findings are consistent in other work then aspirin may affect the development of CD in a middle-aged to elderly population.

Aspirin acetylates multiple cellular proteins in HCT-116 colon cancer cells: Identification of novel targets

Epidemiological and clinical observations provide consistent evidence that regular intake of aspirin may effectively inhibit the occurrence of epithelial tumors; however, the molecular mechanisms are not completely understood. In the present study, we determined the ability of aspirin to acetylate and post-translationally modify cellular proteins in HCT-116 human colon cancer cells to understand the potential mechanisms by which it may exerts anti-cancer effects. Using anti-acetyl lysine antibodies, here we demonstrate that aspirin causes the acetylation of multiple proteins whose molecular weight ranged from 20 to 200 kDa. The identity of these proteins was determined, using immuno-affinity purification, mass spectrometry and immuno-blotting. A total of 33 cellular proteins were potential targets of aspirin-mediated acetylation, while 16 were identified as common to both the control and aspirin-treated samples. These include enzymes of glycolytic pathway, cytoskeleton proteins, histones, ribosomal and mitochondrial proteins. The glycolytic enzymes which were identified include aldolase, glyceraldehyde-3-phosphate dehydrogenase, enolase, pyruvate kinase M2, and lactate dehydrogenase A and B chains. Immunoblotting experiment showed that aspirin also acetylated glucose-6-phosphate dehydrogenase and transketolase, both enzymes of pentose phosphate pathway involved in ribonucleotide biosynthesis. Invitro assays of these enzymes revealed that aspirin did not affect pyruvate kinase and lactate dehydrogenase activity; however, it decreased glucose 6 phosphate dehydrogenase activity. Similar results were also observed in HT-29 human colon cancer cells. Selective inhibition of glucose-6-phosphate dehydrogenase may represent an important mechanism by which aspirin may exert its anti-cancer effects through inhibition of ribonucleotide synthesis.

This Month in Gastroenterology

This Month in Gastroenterology

Effect of Cigarette Smoking on Platelet Aggregation

Cigarette smoking may increase platelet aggregation and cause atherothrombotic cardiovascular events. We aimed to investigate the impact of cigarette smoking on platelet function in patients with ischemic coronary heart disease (CHD). Twenty patients with ischemic stable CHD under aspirin therapy (300 mg/d), who continue to smoking despite all warnings, and 20 nonsmokers with CHD are enrolled in the study. Platelet function is studied at the morning, before and 15 minutes after the first cigarette, by the Platelet Function Analyzer (PFA)-100, with collagen and epinephrine and collagen and adenosine diphosphate cartridges. Post aspirin platelet hyperactivity is defined as having a closure time (CT) shorter than 186 seconds despite regular aspirin intake. Serial CT measurements are analyzed by paired samples t test. Persistent platelet activity was present in 4 smoker (20%) and 3 nonsmoker (15%) patients at the beginning. Platelet activity measured by the PFA-100 is been increased significantly after cigarette smoking (P = .004). Shorter CTs were determined after smoking in all patients with and without baseline persistent platelet activity, and 4 more participants became aspirin nonresponder (P = .004). No significant differences in demographic, hematological, and biochemical parameters were determined between aspirin responders and nonresponders. We determined that cigarette smoking may increase platelet aggregation in patients with ischemic CHD in an aspirin nonresponsive manner. Our results emphasize the importance of quitting cigarette smoking in patients with CHD.

Pharmacological Resistance to Aspirin In Patients with Stable Coronary Artery Disease.

AbstractAbstract 1100 Introduction:Aspirin is the cornerstone of antiplatelet therapy in patients with coronary artery disease (Lancet 1997; 350: 437–439). However, a substantial proportion of patients manifest “breakthrough” events despite regular intake of aspirin suggesting therapeutic resistance to aspirin. Unfortunately, aspirin resistance remains a poorly defined term. There are conflicting reports on the prevalence of aspirin resistance in India. Materials and Methods:We evaluated the prevalence of pharmacological resistance to aspirin therapy in patients with stable and unstable coronary artery disease at a tertiary center in India. One hundred and twenty six patients aged ≥21 with recorded history of previous myocardial infarction (MI) and/or angiographically proven coronary artery disease undergoing routine outpatient cardiac care were enrolled in the study. Eligible patients were recruited 7days after ensuring compliance with a single formulation of aspirin (enteric coated aspirin 150 mg). Compliance was determined by obtaining a history of drug ingestion and performing a pill count. Patients with history of bleeding disorders and those consuming clopidogrel, dipyridamole, or non-steroidal anti- inflammatory drugs were excluded from study. Platelet function analysis was performed using the technique of optical aggregometry (Chronolog 490D, PA, USA). The following agonists (concentrations in parenthesis) were used: ADP (5 μM), Arachidonic acid (0.5 mg/mL), Collagen (2 μg/mL), and Epinephrine (5 μM). A healthy control was run every time a batch of tests was run for subjects. Pharmacological aspirin resistance was defined as the combined demonstration of mean platelet aggregation of ≥ 70% with ADP and a mean aggregation of ≥20% with Arachidonic acid in patients compliant with aspirin therapy. Patients satisfying either one of the above criteria were considered semi-responders (Am J Cardiol 2001; 88:230-5). Results:Out of a total of 126 patients with stable CAD, 64 % were responders, 36 % were non responders (semi-responders = 34% and resistant = 2%). All the patients with acute coronary syndrome (n = 7) were found to be semi-responders. Aspirin resistance did not show any statistically significant correlation with CAD risk factors like history of smoking, diabetes, obesity and hypertension. Of the laboratory parameters, only the total leukocyte count was significantly associated with the presence of aspirin resistance (p<0.03). Surprisingly, this relationship did not extend to either the absolute lymphocyte or neutrophil count. The other laboratory parameters such as hemoglobin, platelet count, hematocrit, mean cell volume, total protein, and albumin did not show any significant statistical relationship with aspirin resistance. To overcome the influence of preanalytical variables, platelet aggregation studies were repeated randomly on 50% of the study population. Paired analysis did not reveal any major changes among the responders and semi responders although the two resistant patients became semi-responders. Conclusion:Pharmacological resistance or semi-responsiveness to aspirin is prevalent in Indian patients with stable coronary artery disease. Long term follow up of these patients to ascertain their clinical outcome will assist in determining the clinical importance of this phenomenon. Disclosures:No relevant conflicts of interest to declare.

Aspirin and alterations in DNA repair proteins in the SW480 colorectal cancer cell line

Regular aspirin intake is associated with a reduction in the incidence of colorectal cancer. Aspirin has been shown to be cytotoxic to colorectal cancer cells in vitro. The molecular basis for this cytotoxicity is controversial, with a number of competing hypotheses in circulation. One suggestion is that the protective effect is related to the induction of expression of the DNA mismatch repair (MMR) proteins hMLH1, hMSH2, hMSH6 and hPMS2 in DNA MMR proficient cells. We report that treatment of the DNA MMR competent/p53 mutant colorectal cancer cell line SW480 with 1 mM aspirin for 48 h caused changes in mRNA expression of several key genes involved in DNA damage signalling pathways, including a significant down-regulation in transcription of the genes ATR, BRCA1 and MAPK12. Increases in the transcription of XRCC3 and GADD45alpha genes are also reported. Regulation of these genes could potentially have profound effects on colorectal cancer cells and may play a role in the observed chemo-protective effect of aspirin in vivo. Although a correlation was not seen between transcript and protein levels of ATR, BRCA1 and GADD45alpha, an increase in XRCC3 encoded protein expression upon aspirin treatment in SW480 cells was observed by immunoblotting, immunofluorescence and immunohistochemical analysis. This is the first report of XRCC3 gene transcription and encoded protein expression being susceptible to exposure to the non-steroidal anti-inflammatory drug, aspirin. Furthermore, this study indicates that alterations in gene transcription seen in microarray studies must be verified at the protein level.