The risk of prostate cancer for men on aspirin, statin or antidiabetic medications

Effect of metformin on incidence, recurrence, and mortality in prostate cancer patients: integrating evidence from real-world studies

PURPOSE

Metformin has been suggested to reduce the risk of cancer. However, previous studies have been inconsistent regarding the relationship between metformin use and the risk of occurrence of prostate cancer (PCa). The purpose of this study was to assess the effect of metformin on clinical outcomes in patients with PCa in a meta-analysis and to explore the possible dose-response relationship.

METHODS

A systematic literature search was conducted in 10 electronic databases and 4 registries. The combined relative risks (RRs) were calculated using a random-effects model with 95% confidence interval (CIs) to assess the effect of metformin on the risk of PCa. Relevant subgroup analyses and sensitivity analyses were performed.

RESULTS

The across studies results show that metformin use associated with lower incidence of PCa (RR: 0.82, 95% CI: 0.74-0.91). Metformin use was also found to reduce PCa recurrence, but the results were not statistically significant (RR: 0.97, 95% CI: 0.81-1.15). Metformin use was not associated with PCa mortality (RR: 0.94, 95% CI: 0.81-1.09). The results of subgroup analyses indicated that the type of study was a cohort study and the population came from both Asia and Europe showed that taking metformin reduced the incidence of PCa. A linear correlation was found between the duration of metformin use and its protective effect.

CONCLUSIONS

This meta-analysis revealed an independent correlation between metformin use and reduced incidence of PCa. Metformin use was not associated with either PCa recurrence rate or mortality. Furthermore, the effect of metformin on PCa incidence was found to be related to duration.

Impact of aspirin on biochemical recurrence of prostate cancer after robot assisted radical prostatectomy in a multicenter retrospective cohort study

This study evaluated the impact of aspirin on the biochemical recurrence (BCR) rate following robot-assisted radical prostatectomy (RARP) in patients. A database search identified patients who underwent RARP for pT2-3N0M0 disease at any of 25 centers between 2011 and 2022, categorized into aspirin (n = 350) and control groups (n = 5857). Adjustment by 1:1 propensity score matching (PSM) and Mahalanobis distance matching (MDM) created 350 matched pairs. The effect of aspirin on the BCR rate was evaluated by analysis of BCR-free survival. After PSM and MDM, the 3-year BCR-free rate was significantly better in the aspirin group (85.0%, 95% confidence interval [CI] 80.8-89.4) than in the control group (PSM, 74.5%, 95% CI 66.5-83.5, p = 0.021; MDM, 74.7%, 95% CI 66.3-84.3, p = 0.037). In the analysis of high-risk subgroups, patients in the aspirin group with an ISUP (International Society of Urological Pathology) grade ≥ 4 had a significantly lower recurrence rate in both matched groups (PSM, hazard ratio 0.44, 95% CI 0.22-0.88; MDM, hazard ratio 0.45, 95% CI 0.23-0.90). In conclusion, this study suggests that aspirin could enhance BCR-free survival post-RARP, especially in patients with higher ISUP grades.

Efficacy of metformin drug in preventing metabolic syndrome associated with androgen deprivation therapy (ADT) in prostate cancer patients: A systematic review and meta-analysis

BACKGROUND

Prostate cancer patients undergoing long-term (Androgen deprivation therapy) ADT will tend to have metabolic changes. Metabolic syndrome represents the accumulation of several medical conditions that significantly increase the risk of developing severe diseases like cardiovascular disorders, insulin resistance, and hyperglycemia. We are conducting this systematic review and meta-analysis to fill up the gap and to resolve the debate regarding the effectiveness of metformin in reducing metabolic syndrome associated with ADT in prostate cancer patients.

METHODS

We conducted the systematic review and meta-analysis according to the Handbook of Cochrane Systematic Review of Intervention and the PRISMA guidelines. We conducted the search process using the following databases: the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Scopus, and Web of Science. We selected the articles that fit within the following criteria, Randomized Controlled Trials (RCTs) and Cohort studies which evaluate the efficacy of metformin in reducing metabolic syndromes for prostate cancer patients undergoing androgen deprivation therapy (ADT). The efficacy of metformin in metabolic syndrome that resulted from using androgen deprivation therapy for prostate cancer patients was evaluated by the changes from baseline in Body Mass Index (BMI), waist circumference by cm, glycated hemoglobin (HbA1c), and blood pressure both systolic and diastolic. Revman software Version 5.4.1 was used to perform all statistical analyses.

RESULTS

Our search retrieved 781 records. Seven records were included in our study: 5 published randomized control clinical trials and 2 cohort studies and only 6 studies were included in the meta-analysis. For BMI the pooled effect estimates of 3 studies favored Metformin over placebo, but this is not a significant difference (MD = -0.9, P = 0.05), for systolic pressure the pooled effect estimates of 3 studies favored Metformin over placebo, but this is not a significantly different placebo (MD = -3.18, P = 0.22), for HBA1c the pooled effect estimates of 3 studies showed that no significant difference between placebo and metformin (MD = -0.01, P = 0.86)002E CONCLUSION: Despite the promising direction in some parameters, our findings underscore the need for further research to establish a clearer understanding of metformin's role in mitigating metabolic changes in prostate cancer patients undergoing ADT.

Advancements in precision nanomedicine design targeting the anoikis-platelet interface of circulating tumor cells

Tumor metastasis, the apex of cancer progression, poses a formidable challenge in therapeutic endeavors. Circulating tumor cells (CTCs), resilient entities originating from primary tumors or their metastases, significantly contribute to this process by demonstrating remarkable adaptability. They survive shear stress, resist anoikis, evade immune surveillance, and thwart chemotherapy. This comprehensive review aims to elucidate the intricate landscape of CTC formation, metastatic mechanisms, and the myriad factors influencing their behavior. Integral signaling pathways, such as integrin-related signaling, cellular autophagy, epithelial-mesenchymal transition, and interactions with platelets, are examined in detail. Furthermore, we explore the realm of precision nanomedicine design, with a specific emphasis on the anoikis‒platelet interface. This innovative approach strategically targets CTC survival mechanisms, offering promising avenues for combatting metastatic cancer with unprecedented precision and efficacy. The review underscores the indispensable role of the rational design of platelet-based nanomedicine in the pursuit of restraining CTC-driven metastasis.

Effect of aspirin on incidence, recurrence, and mortality in prostate cancer patients: integrating evidence from randomized controlled trials and real-world studies

PURPOSE

Aspirin has been suggested to reduce the risk of cancer. However, previous studies have been inconsistent regarding the relationship between aspirin use and the risk of occurrence of prostate cancer (PCa). The purpose of this study was to assess the effect of aspirin on clinical outcomes in patients with PCa in a meta-analysis and to explore the possible dose-response relationship.

METHODS

A systematic literature search was conducted in 10 electronic databases and 4 registries. The combined relative risks (RRs) were calculated using a random-effects model with 95% confidence interval (CIs) to assess the effect of aspirin on the risk of PCa. Relevant subgroup analyses and sensitivity analyses were performed.

RESULTS

The across studies results show that aspirin use associated with lower incidence of PCa (RR: 0.96, 95% CI: 0.95-0.98), and reduced mortality (RR: 0.88, 95% CI: 0.82-0.95). The results of the subgroup analysis indicated that both cohort and population studies in the Americas showed a reduction in PCa incidence and mortality with aspirin use. A linear correlation was observed between dosage/duration of aspirin use and its protective effect. Additionally, post-diagnosis aspirin use was associated with decreased risk of PCa mortality.

CONCLUSIONS

This meta-analysis revealed an independent correlation between the use of aspirin and reductions in both the incidence and mortality rates of PCa. However, randomized controlled trials did not find any association between aspirin use and PCa. Furthermore, the impact of aspirin on PCa occurrence was found to be dependent on both dosage and duration.

Metformin and Aspirin: Anticancer effects on A549 and PC3 cancer cells and the mechanisms of action

Metformin exerts its anticancer effect through two mechanisms, directly affecting the tumor and indirectly reducing systemic insulin levels. The anticancer effects of aspirin occur by inhibiting Cyclooxygenase (COX)-2. COX-2 is absent in many cell types under normal conditions and increases under pathological conditions such as cancer. This study aims to investigate the effect of metformin and aspirin and their combination of them on A549 and PC3 cell lines. Metformin and aspirin were investigated separately and in combination on two cancer cell lines, A549 and PC3. The examined groups include the negative control of untreated cells and the positive control of cisplatin and drugs at concentrations of 15, 10, and 20 μg/ mL to investigate the mechanism of oxidative stress factors (reactive oxygen species, lipid peroxidation, Glutathione (GSH)) and apoptosis (lactate dehydrogenase). The results showed that aspirin, metformin, and their combination could affect cancer cell growth by damaging mitochondria, releasing reactive oxygen species, and activating the oxidative stress pathway. Also, these two drugs show the activation of the apoptotic pathway in cancer cells by increasing the lactate dehydrogenase factor and releasing it from the cells. By disrupting the balance of oxidants and antioxidants in the cell, metformin and aspirin cause an increase in the level of reactive oxygen species and a decrease in the level of glutathione reserves, followed by an increase in the level of lipid peroxidation and a decrease in cell viability. Unlike common chemotherapy drugs, these drugs have no known severe side effects; Therefore, in the not-so-distant future, these drugs can also be used as anticancer drugs.

Highlights

Metformin and aspirin, commonly used drugs for diabetes and inflammation, inhibit the growth of cancer cell lines, A549 and PC3.Metformin and aspirin, either separately or in combination, can potentially impede cancer cell growth by disrupting mitochondrial function, inducing the release of reactive oxygen species (ROS), and activating oxidative stress pathways.Furthermore, these drugs can trigger apoptosis, a programmed cell death mechanism, in cancer cells by increasing lactate dehydrogenase (LDH) levels and facilitating its release from the cells.

Published registry-based pharmacoepidemiologic associations show limited concordance with agnostic medication-wide analyses

OBJECTIVES

To assess how the results of published national registry-based pharmacoepidemiology studies (where select associations are of interest) compare with an agnostic medication-wide approach (where all possible drug associations are tested).

STUDY DESIGN AND SETTING

We systematically searched for publications that reported drug associations with any, breast, colon/colorectal, or prostate cancer in the Swedish Prescribed Drug Registry. Results were compared against a previously performed agnostic medication-wide study on the same registry.

PROTOCOL

https://osf.io/kqj8n.

RESULTS

Most published studies (25/32) investigated previously reported associations. 421/913 (46%) associations had statistically significant results. 134 of the 162 unique drug-cancer associations could be paired with 70 associations in the agnostic study (corresponding drug categories and cancer types). Published studies reported smaller effect sizes and absolute effect sizes than the agnostic study, and generally used more adjustments. Agnostic analyses were less likely to report statistically significant protective associations (based on a multiplicity-corrected threshold) than their paired associations in published studies (McNemar odds ratio 0.13, P = 0.0022). Among 162 published associations, 36 (22%) showed increased risk signal and 25 (15%) protective signal at P < 0.05, while for agnostic associations, 237 (11%) showed increased risk signal and 108 (5%) protective signal at a multiplicity-corrected threshold. Associations belonging to drug categories targeted by individual published studies vs. nontargeted had smaller average effect sizes; smaller P values; and more frequent risk signals.

CONCLUSION

Published pharmacoepidemiology studies using a national registry addressed mostly previously proposed associations, were mostly "negative", and showed only modest concordance with their respective agnostic analyses in the same registry.

Targeting lipid metabolism in metastatic prostate cancer

Despite key advances in the treatment of prostate cancer (PCa), a proportion of men have de novo resistance, and all will develop resistance to current therapeutics over time. Aberrant lipid metabolism has long been associated with prostate carcinogenesis and progression, but more recently there has been an explosion of preclinical and clinical data which is informing new clinical trials. This review explores the epidemiological links between obesity and metabolic syndrome and PCa, the evidence for altered circulating lipids in PCa and their potential role as biomarkers, as well as novel therapeutic strategies for targeting lipids in men with PCa, including therapies widely used in cardiovascular disease such as statins, metformin and lifestyle modification, as well as novel targeted agents such as sphingosine kinase inhibitors, DES1 inhibitors and agents targeting FASN and beta oxidation.

Association of Statin Use with the Risk of Incident Prostate Cancer: A Meta-Analysis and Systematic Review

Background

With the growth and aging of population, the incidence of prostate cancer will increase year by year, which is bound to bring greater economic burden to the society. There has been greater interest in the anticancer effects of statin in recent years. It is controversial whether statin use is associated with the risk of prostate cancer (PCa). Thus, we conducted a meta-analysis and systematic review to explore the effects of statin use and their duration and cumulative dose on the overall incidence of PCa.

Method

The study was conducted according to the latest guidelines for PRISMA 2020. We searched PubMed and other databases for studies about the association of statin use with the risk of incident prostate cancer between January 1, 1990, and April 11, 2022. Two independent researchers extracted data and evaluated the quality of the studies. R x64 4.1.2 and random-effects model were used for data statistics. Relative risk (RR) and odds ratio (OR) effective values with a 95% confidence interval (95% CI) were used to assess the main results.

Results

The results of 6 RCT and 26 cohort studies showed that statins did not significantly associate with the incidence of PCa (RR = 0.94, 95% CI: 0.82-1.08). The similar results were obtained from 9 case-control studies (OR = 1.03, 95% CI: 0.99-1.07). However, statins were associated with a lower risk of Pca (RR = 0.44, 95% CI: 0.28-0.70) when the cumulative defined daily dose (cDDD) was high. Using statins for more than five years could be associated with a reduced incidence of Pca (RR = 0.47, 95% CI: 0.23-0.97). There was a significant heterogeneity in these studies (RCT and cohort study: I ² = 98%, P < 0.01; case-control study: I ² = 72%, P < 0.01).

Conclusion

We concluded that statins had a neutral association with the overall risk of PCa. High cDDD and long duration were associated with a lower risk of PCa.

Correlation Between Long-Term Acetylsalicylic Acid Use and Prostate Cancer Screening with PSA. Should We Reduce the PSA Cut-off for Patients in Chronic Therapy? A Multicenter Study

Purpose

To evaluate the prostate cancer (PCa) detection rate in men with chronic use of Aspirin and to compare it with the detection rate of non-users.

Patients and Methods

Prospectively maintained database regarding patients undergoing prostate biopsy over the last 10 years in five institutions. Patients were divided into two groups according to their exposure to Aspirin. We relied on multivariable linear and logistic regression models to test whether Aspirin administration was associated with lower PSA values at prostate biopsy, higher PCa diagnosis, and higher Gleason Grade Grouping (GGG) at biopsy.

Results

Were identified 1059 patients, of whom 803 (76%) did not take Aspirin vs 256 (24%) were taking it. In multivariable log-linear regression analysis, Aspirin administration was associated with lower PSA levels (OR 0.83, 95% CI 0.71–0.97, p = 0.01), after controlling for age, prostate volume, smoking history, associated inflammation at prostate biopsy, presence of PCa at biopsy, and GGG. In multivariable logistic regression analysis, Aspirin administration was not found to be a predictor of PCa at prostate biopsy (OR 1.40, 95% CI 0.82–2.40, p = 0.21) after controlling for age, PSA, smoking history, prostate volume, findings at digital rectal examination and the number of biopsy cores. In patients with PCa at prostate biopsy (n = 516), Aspirin administration was found to predict higher GGG (OR 2.24, 95% CI 1.01–4.87, p = 0.04).

Conclusion

Aspirin administration was found to be a predictor of more aggressive GGG. These findings suggest that a lower PSA threshold should be considered in patients taking Aspirin, as, despite low PSA levels, they might harbour aggressive PCa.

Chemopreventive Effects of Concomitant or Individual Use of Statins, Aspirin, Metformin, and Angiotensin Drugs: A Study Using Claims Data of 23 Million Individuals

Despite previous studies on statins, aspirin, metformin, and angiotensin-converting-enzyme inhibitors (ACEIs)/angiotensin II receptor blockers (ARBs), little has been studied about all their possible combinations for chemoprevention against cancers. This study aimed to comprehensively analyze the composite chemopreventive effects of all the combinations. In this case-control study, health records were retrieved from claims databases of Taiwan’s Health and Welfare Data Science Center. Eligible cases were matched at a 1:4 ratio with controls for age and sex. Both cases and controls were categorized into 16 exposure groups based on medication use. A total of 601,733 cancer cases were identified. Cancer risks (denoted by adjusted odds ratio; 99% confidence interval) were found to be significantly decreased: overall risk of all cancers in statin-alone (0.864; 0.843, 0.886), aspirin-alone (0.949; 0.939, 0.958), and ACEIs/ARBs (0.982; 0.978, 0.985) users; prostate (0.924; 0.889, 0.962) and female breast (0.967; 0.936, 1.000) cancers in metformin-alone users; gastrointestinal, lung, and liver cancers in aspirin and/or ACEIs/ARBs users; and liver cancer (0.433; 0.398, 0.471) in statin users. In conclusion, the results found no synergistic effect of multiple use of these agents on cancer prevention. Use of two (statins and aspirin, statins and metformin, statins and ACEIs/ARBs, and aspirin and ACEIS/ARBs) showed chemopreventive effects in some combinations, while the use of four, in general, did not.

Antidiabetic Medications and the Risk of Prostate Cancer in Patients with Diabetes Mellitus: A Systematic Review and Meta-analysis

BACKGROUND

Antidiabetic medications (ADMs) may modify prostate cancer (PCa) risk in patients with diabetes mellitus (DM). Accordingly, the current study assessed the possible associations between ADMs and the risk of PCa in diabetics.

METHODS

A systematic literature search (PubMed, Embase and Cochrane Library) identified studies evaluating the associations between ADMs and incidence of PCa. A meta-analysis followed PRISMA was performed using odds ratio (OR) with 95% confidence interval (CI) as effect measures.

RESULTS

In total of 47 studies involving 3,094,152 patients with diabetes were included. Results of meta-analysis of the observational studies suggested no significant association between metformin, thiazolidinediones, sulfonylureas, insulin or dipeptidyl peptidase-4 inhibitors administration and the risk of PCa (All p-values > 0.05). Separate analysis of randomized controlled trials (RCTs) revealed a significant reduction in PCa risk with thiazolidinediones (OR = 0.55, p = 0.04) or glucagon-like peptide-1 receptor agonists (GLP-1RA) administration (OR = 0.53, p = 0.006), whereas no significant association was found in SGLT2 inhibitors (p = 0.3).

CONCLUSION

Thiazolidinediones or GLP-1RA administration may have benefits in PCa based on RCTs, however, further research is needed to confirm these findings.

Outcomes of Screening for Prostate Cancer Among Men Who Use Statins

Importance

Prostate-specific antigen (PSA) screening for prostate cancer has resulted in a slight reduction in prostate cancer mortality but also a concomitant overdiagnosis of low-risk tumors. Prostate-specific antigen levels are affected by use of cholesterol-lowering statin drugs, but the association of statin use with PSA screening performance is unknown.

Objective

To investigate whether statin use was associated with outcomes of a randomized PSA-based prostate cancer screening intervention.

Design, Setting, and Participants

This post hoc subgroup analysis of a cohort from a population-based randomized clinical trial used data from the population-based Finnish Randomized Study of Prostate Cancer Screening, which randomized men to PSA screening or routine care from March 1, 1996, to December 31, 1999, with follow-up continuing until December 31, 2015. The population included all men aged 55 to 67 years at baseline and residing in the Tampere or Helsinki districts of Finland. Information on statin purchases from 1996 to 2009 was obtained from a national prescription registry. Eligible men were identified from the population registry of Finland. Prevalent prostate cancer cases at baseline were excluded. Data were analyzed from January 1, 2019 to March 31, 2021.

Interventions

Three invitations for PSA screening at 4-year intervals from 1996 to 2007 vs routine care.

Main Outcomes and Measures

Risk for prostate cancer overall, high-risk disease, and prostate cancer mortality in the screening group vs the control group as an intention-to-treat analysis. The analysis was stratified by statin use.

Results

The study comprised 78 606 men (median age, 59 years [range, 55-67 years]) with statin purchase data available. Although PSA screening was associated with increased prostate cancer incidence among statin nonusers (screening vs control, 11.2 vs 8.6 per 1000 person-years); rate ratio [RR], 1.31; 95% CI, 1.24-1.38), no similar increase in incidence was observed among statin users (6.9 vs 5.9 per 1000 person-years; RR, 1.02; 95% CI, 0.95-1.10; P < .001 for interaction). Incidence of low-risk (Gleason score 6) and localized tumors was lower among statin users, whereas detection of tumors with a Gleason score of 8 to 10 was similar. Screening was associated with a lower incidence of metastatic tumors regardless of statin use.

Conclusion and Relevance

In this post hoc subgroup analysis of a cohort from a population-based randomized clinical trial, PSA screening among statin users was associated with a decreased incidence of advanced prostate cancer that was similar among statin nonusers, but with less increase in detection of low-grade localized tumors in statin users than in nonusers. These findings suggest that statin use does not materially compromise benefits of PSA-based screening.

Bidirectional Interaction Between Cancer Cells and Platelets Provides Potential Strategies for Cancer Therapies

Platelets are essential components in the tumor microenvironment. For decades, clinical data have demonstrated that cancer patients have a high risk of thrombosis that is associated with adverse prognosis and decreased survival, indicating the involvement of platelets in cancer progression. Increasing evidence confirms that cancer cells are able to induce production and activation of platelets. Once activated, platelets serve as allies of cancer cells in tumor growth and metastasis. They can protect circulating tumor cells (CTCs) against the immune system and detachment-induced apoptosis while facilitating angiogenesis and tumor cell adhesion and invasion. Therefore, antiplatelet agents and platelet-based therapies should be developed for cancer treatment. Here, we discuss the mechanisms underlying the bidirectional cancer-platelet crosstalk and platelet-based therapeutic approaches.

Effect of Statins on the Risk of Different Stages of Prostate Cancer: A Meta-Analysis

INTRODUCTION

The aim of this article was to investigate the relationship between statins and the risk of different stages or grades of prostate cancer.

METHODS

A comprehensive literature search was performed for articles published until December 18, 2020, on the PubMed, Embase, and the Cochrane Library databases. The pooled relative risk (RR) and 95% confidence interval (CI) were then analyzed using the STATA.16.0 software.

RESULTS

A total of 588,055 patients from 14 studies were included in the analysis. We found that the use of statins expressed a significant correlation with a lower risk of advanced prostate cancer (RR = 0.81, 95% CI: 0.73-0.91; RR = 0.86, 95% CI: 0.75-0.99, respectively). However, no evidence suggested that the use of statins was beneficial for the prevention of localized prostate cancer incidence. Similarly, the pooled results also revealed no association between the use of statins and the risk of high-grade and low-grade prostate cancer.

CONCLUSION

It has been found that the use of statins is associated with a lower risk of advanced prostate cancer but was not related to the risk of localized, low-grade, or high-grade prostate cancer.

Metformin addition to androgen deprivation therapy effect on cancer prostate patients with type 2 diabetes

AIMS

Patients with prostate cancer (PC) have a higher rate of non-cancer mortality than cancer-related, which could be partially attributed to the treatment they receive. We aimed to evaluate the effect of metformin addition to androgen deprivation therapy (ADT) among cancer prostate patients with type 2 DM.

METHODOLOGY

This prospective, two-arm study included 95 PC patients with type 2 DM who had ADT. The patients were divided into 2 groups: the Metformin group includes 48 patients and the non-metformin group includes 47 patients. We compared the anthropometric, diabetic status; tumour status, survival rate, and biochemical relapse between metformin and non-metformin groups.

RESULTS

We observed significant differences in fold changes of anthropometric parameters including weight, BMI, and waist circumference between both groups. We found significant differences in fold change of PSA levels in metformin groups in comparison with non-metformin groups. Overall survival comparison between metformin users and non-users showed better statistically insignificant survival in the metformin users group. We observed a significantly lower relapse rate in the metformin group in comparison with the non-metformin.

CONCLUSION

Metformin could decrease some of the unfavourable metabolic consequences of ADT. Moreover, Metformin could enhance the tumour-suppressive effect of ADT and decrease the PSA relapse rate.

Current Status and Application of Metformin for Prostate Cancer: A Comprehensive Review

Metformin, an oral biguanide used for first-line treatment of type 2 diabetes mellitus, has attracted attention for its anti-proliferative and anti-cancer effects in several solid tumors, including prostate cancer (PCa). Liver kinase B1 (LKB1) and adenosine monophosphate-activated protein kinase (AMPK) activation, inhibition of the mammalian target of rapamycin (mTOR) activity and protein synthesis, induction of apoptosis and autophagy by p53 and p21, and decreased blood insulin level have been suggested as direct anti-cancer mechanisms of metformin. Research has shown that PCa development and progression are associated with metabolic syndrome and its components. Therefore, reduction in the risk of PCa and improvement in survival in metformin users may be the results of the direct anti-cancer mechanisms of the drug or the secondary effects from improvement of metabolic syndrome. In contrast, some research has suggested that there is no association between metformin use and PCa incidence or survival. In this comprehensive review, we summarize updated evidence on the relationship between metformin use and oncological effects in patients with PCa. We also highlight ongoing clinical trials evaluating metformin as an adjuvant therapy in novel drug combinations in various disease settings.

Lipid composition of the cancer cell membrane

Cancer cell possesses numerous adaptations to resist the immune system response and chemotherapy. One of the most significant properties of the neoplastic cells is the altered lipid metabolism, and consequently, the abnormal cell membrane composition. Like in the case of phosphatidylcholine, these changes result in the modulation of certain enzymes and accumulation of energetic material, which could be used for a higher proliferation rate. The changes are so prominent, that some lipids, such as phosphatidylserines, could even be considered as the cancer biomarkers. Additionally, some changes of biophysical properties of cell membranes lead to the higher resistance to chemotherapy, and finally to the disturbances in signalling pathways. Namely, the increased levels of certain lipids, like for instance phosphatidylserine, lead to the attenuation of the immune system response. Also, changes in lipid saturation prevent the cells from demanding conditions of the microenvironment. Particularly interesting is the significance of cell membrane cholesterol content in the modulation of metastasis. This review paper discusses the roles of each lipid type in cancer physiology. The review combined theoretical data with clinical studies to show novel therapeutic options concerning the modulation of cell membranes in oncology.

Association of type 2 diabetes mellitus and antidiabetic medication with risk of prostate cancer: a population-based case-control study

BACKGROUND

Prostate cancer (PCa) and type 2 diabetes mellitus (T2DM) are prevalent conditions that often occur concomitantly. However, many aspects of the impact of T2DM, particularly the duration of T2DM and antidiabetic medications, on PCa risk are poorly understood.

METHODS

To assess the association of duration of T2DM and antidiabetic medication with PCa risk, we designed a matched case-control study, including 31,415 men with PCa and 154,812 PCa-free men in Prostate Cancer data Base Sweden (PCBaSe) 4.1.

RESULTS

Overall, a decreased risk of PCa was observed for men with T2DM (odds ratio (OR): 0.81, 95% confidence interval (CI): 0.78-0.84), as compared to men without T2DM. The decreased risk of PCa was consistently showed across duration of T2DM. With respect to use of antidiabetic drugs, this inverse association with duration was also found for all medications types, as compared to men without T2DM, including insulin, metformin and sulphonylurea (SU) (e.g. 3- < 5 yr insulin OR:0.69, 95%CI:0.60-0.80; 3- < 5 yr metformin OR: 0.82, 95%CI: 0.74-0.91; 3- < 5 yr SU OR: 0.72, 95%CI: 0.62-0.83). When stratifying by PCa risk categories, this decreased risk was most evident for diagnosis of low and intermediate-risk PCa (low-risk OR: 0.65, 95%CI: 0.66-0.70, intermediate-risk OR: 0.80, 95%CI: 0.75-0.85).

CONCLUSIONS

The study showed an inverse association between pre-existing T2DM and PCa across different durations of T2DM and all types of T2DM medication received. This inverse association was most evident for low- and intermediate-risk PCa, suggesting that whilst T2DM and its medication may protect some men from developing PCa, the relationship warrants further study.

Effect of metformin on the risk of prostate cancer in patients with type 2 diabetes by considering different confounding factors: a meta-analysis of observational studies

Preclinical studies have suggested the antitumorigenic properties of metformin on prostate cancer; results from epidemiological studies remain contradictory. We aim to investigate the evidence of metformin and the risk of prostate cancer. PubMed, Embase, Cochrane Library, and Web of Science databases were searched for eligible studies. Meta-analyses were carried out using the most fully adjusted hazard ratios and the corresponding 95% confidence intervals. Eighteen cohort studies and six case-control studies representing 2 009 504 male patients with type 2 diabetes mellitus were identified. The pooled HR of prostate cancer for metformin therapy was 0.97 (0.84-1.12) in case-control studies and 0.94 (0.79-1.12) in cohort studies, respectively. In cohort studies, we found that there was a modest association in studies with samples from Europe, but not in studies with samples from North America, Asia, and Oceania. In addition, metformin showed a slightly protective effect compared with sulfonylurea, but not insulin and other comparators. Meta-regression analyses found that obesity and prostate-specific antigen adjustment in statistical models may be the sources of heterogeneity. However, there were no significant differences in subgroups stratified by time-related biases, analytical approaches, types of risk estimates, study quality, publication year, and whether adjusted for smoking, alcohol abuse, hemoglobin A1c, diabetes duration, and other confounding factors. Our study showed that metformin therapy was not associated with the risk of prostate cancer in patients with type 2 diabetes mellitus. However, exploratory analyses suggest that metformin use may be protective in a certain subgroup of patients.

Association Between Antidiabetic Medications and Prostate-Specific Antigen Levels and Biopsy Results

IMPORTANCE

Diabetic men appear to have a lower risk of prostate cancer. Whether antidiabetic medications are protective or potentially mask prostate cancer by lowering prostate-specific antigen (PSA) levels is unclear.

OBJECTIVE

To examine the associations of antidiabetic medication use with (1) PSA levels, (2) frequency of PSA testing, (3) receipt of biopsy following elevated PSA results, and (4) prostate cancer detection at biopsy.

DESIGN, SETTING, AND PARTICIPANTS

Population-based cohort study using data from the Stockholm PSA and Biopsy Register. Participants were all prostate cancer-free men aged 40 to 79 years residing in Stockholm County, Sweden, between January 1, 2006, and December 31, 2015. Data were analyzed from November 2018 to March 2019.

EXPOSURES

One or more prescription for metformin, sulfonylurea, or insulin, as recorded in Sweden's National Prescribed Drug Register.

MAIN OUTCOMES AND MEASURES

Levels of PSA following first exposure to antidiabetic medications were assessed using multivariable linear regression. Frequency of PSA testing was assessed via multivariable Poisson regression. Biopsy following elevated PSA (≥3.0 ng/mL) and prostate cancer detection at biopsy were assessed via multivariable logistic regression.

RESULTS

The cohort of 564 666 men (median [range] age, 65 [40-79] years) consisted of 4583 men initially exposed to metformin, 1104 exposed to sulfonylurea, and 978 exposed to insulin who were age matched with unexposed men (1:5). Exposed men had lower median (interquartile range) PSA levels before starting antidiabetic medications compared with unexposed men (1.2 [0.7-2.5] vs 1.6 [0.8-3.2] ng/mL). After accounting for baseline differences, PSA levels did not vary from those of unexposed men following exposure to antidiabetic medications. Frequency of PSA testing was higher for those receiving metformin (rate ratio, 1.07; 95% CI, 1.06-1.09) and sulfonylurea (rate ratio, 1.06; 95% CI, 1.03-1.08) but was lower for those receiving insulin (rate ratio, 0.79; 95% CI, 0.77- 0.81). Likelihood of biopsy after elevated PSA was lower among men receiving metformin (odds ratio, 0.87; 95% CI, 0.80-0.96) and insulin (odds ratio, 0.83; 95% CI, 0.74-0.93). There were no differences in prostate cancer detection at biopsy, regardless of PSA levels that triggered the biopsy.

CONCLUSIONS AND RELEVANCE

This study's findings do not support the hypothesis that the inverse association between diabetes and prostate cancer is mediated through antidiabetic medications lowering PSA levels to mask prostate cancer. They do suggest potential detection bias due to fewer biopsies among men receiving antidiabetic medications, which may explain the lower prostate cancer risk in men with diabetes.

Assessment of biochemical recurrence of prostate cancer (Review)

The assessment of the risk of biochemical recurrence (BCR) is critical in the management of males with prostate cancer (PC). Over the past decades, a comprehensive effort has been focusing on improving risk stratification; a variety of models have been constructed using PC-associated pathological features and molecular alterations occurring at the genome, protein and RNA level. Alterations in RNA expression (lncRNA, miRNA and mRNA) constitute the largest proportion of the biomarkers of BCR. In this article, we systemically review RNA-based BCR biomarkers reported in PubMed according to the PRISMA guidelines. Individual miRNAs, mRNAs, lncRNAs and multi-gene panels, including the commercially available signatures, Oncotype DX and Prolaris, will be discussed; details related to cohort size, hazard ratio and 95% confidence intervals will be provided. Mechanistically, these individual biomarkers affect multiple pathways critical to tumorigenesis and progression, including epithelial-mesenchymal transition (EMT), phosphatase and tensin homolog (PTEN), Wnt, growth factor receptor, cell proliferation, immune checkpoints and others. This variety in the mechanisms involved not only validates their associations with BCR, but also highlights the need for the coverage of multiple pathways in order to effectively stratify the risk of BCR. Updates of novel biomarkers and their mechanistic insights are considered, which suggests new avenues to pursue in the prediction of BCR. Additionally, the management of patients with BCR and the potential utility of the stratification of the risk of BCR in salvage treatment decision making for these patients are briefly covered. Limitations will also be discussed.

Metformin use and prostate cancer risk: A meta-analysis of cohort studies

BACKGROUND

The relationship between metformin use and the risk of prostate cancer is still inconclusive. Therefore, we performed a systematic review and meta-analysis of all eligible cohort studies to evaluate a potential association of metformin use with prostate cancer risk.

METHODS

A comprehensive literature search was performed in PubMed and Web of Science databases through July 2018. A DerSimonian and Laird random-effects model was applied to calculate the pooled relative risk (RR) and its 95% confidence interval (CI).

RESULTS

Eighteen cohort or nested case-control studies were included in this study with a total of 52,328 cases. In a random-effect pooled analysis, metformin use was not significantly associated with the risk of prostate cancer (RR 0.97, 95% CI 0.80-1.16, P = .711). Statistically significant heterogeneity was identified among included studies (P < .001, I = 98.1%). Sensitivity analysis indicated that no single study dominated the pooled RR.

CONCLUSION

The present large meta-analysis of cohort studies did not find an association between metformin use and prostate cancer risk.

The effect of metformin therapy on incidence and prognosis in prostate cancer: A systematic review and meta-analysis

The relationship between metformin and prostate cancer (PCa) remains controversial. To clarify this association, the PubMed, Embase and Cochrane library databases were systematically searched from their inception dates to May 23, 2018, using the keywords "metformin" and "prostate cancer" to identify the related studies. The results included incidence, overall survival (OS), PCa-specific survival (CSS) and recurrence-free survival (RFS), which were measured as hazard ratios (HR) with a 95% confidence interval (95% CI) using Review Manager 5.3 software. A total of 30 cohort studies, including 1,660,795 patients were included in this study. Our study revealed that metformin treatment improves OS, CSS and RFS in PCa (HR = 0.72, 95% CI: 0.59-0.88, P = 0.001; HR = 0.78, 95% CI: 0.64-0.94, P = 0.009; and HR = 0.60, 95% CI: 0.42-0.87 P = 0.006, respectively) compared with non-metformin treatment. However, metformin usage did not reduce the incidence of PCa (HR = 0.86, 95% CI: 0.55-1.34, P = 0.51). In conclusion, compared with non-metformin treatment, metformin therapy can significantly improve OS, CSS and RFS in PCa patients. No association was noted between metformin therapy and PCa incidence. This study indicates a useful direction for the clinical treatment of PCa.

Statin and metformin therapy in prostate cancer patients with hyperlipidemia who underwent radiotherapy: a population-based cohort study

Purpose

To evaluate the association between the use of statins and/or metformin and patient survival in prostate cancer patients in Taiwan.

Subjects and methods

Newly diagnosed prostate cancer patients who had hyperlipidemia and received radiotherapy were identified from the National Health Insurance Research Database 2000–2010. The survival rate was estimated by the Kaplan–Meier method. Univariate and multivariate Cox regression analyses were performed to examine the association of mortality. Sensitivity analysis was performed to assess the risk of mortality in patients with diabetes.

Results

The study included 567 patients. Patients who used statins or metformin after prostate cancer diagnosis had longer average survival times (9.3 years and 8.1 years, respectively; P=0.001) compared with patients who persistently used or used the medicines prior to cancer diagnosis. Multivariate Cox regression analysis found that patients treated with statins after cancer diagnosis were significantly associated with a lower risk of mortality (aHR =0.24, 95% CI =0.09–0.66) compared to patients who did not use statins during the study period. Patients treated with metformin after cancer diagnosis were significantly associated more with an increased risk of mortality (aHR =6.78, 95% CI =2.45–18.77) compared to patients who did not use metformin during the study period. Sensitivity analysis revealed that the average survival time was similar among different medicine use groups in patients with diabetes.

Conclusion

The finding suggests that statins and metformin use after prostate cancer diagnosis may increase survival in patients with hyperlipidemia and radiotherapy.

The anticancer potential of metformin on prostate cancer

BACKGROUND

Prostate cancer (PCa) is characterized as the most frequent type of cancer in males. Recent research has suggested patients who have diabetes mellitus taking metformin (MF) have a lower risk of PCa. MF has antineoplastic effects such as adenosine monophosphate-activated protein kinase (AMPK)-dependent and independent mechanisms, suppression of androgen signaling pathway, and alterations of insulin-like growth factor-1 (IGF-1) signaling pathways that cause the growth and proliferation of PCa. Based on epidemiological factors, patients with diabetes mellitus may have a protective effect on PCa.

METHODS

A literature search on MEDLINE® was conducted using a combined query of "prostate cancer" and "metformin" to yield publications unveiling the mechanisms of action, biological effects, epidemiological evidence, and research advances of MF with respect to PCa.

RESULTS

Evidence has shown that MF has multiple antineoplastic effects through AMPK-dependent and independent mechanisms, the alteration of IGF-1 signaling pathways, suppression of the androgen receptor pathway, inhibition of the mTOR pathway, and lipogenesis. Conduction of meta-analysis suggests mortality benefit to patients who exhibit PCa when taking MF. Clinical trials have shown evidence, demonstrating MF to improving significantly.

CONCLUSIONS

Herewith we review the literature regarding the numerous mechanisms of action of MF on PCa in order to decrease or repress the growth, proliferation, and differentiation of PCa cells. We analyze the molecular impacts of MF as well as adjunct therapies such as androgen deprivation therapy, aspirin, statin, or chemotherapy, proposing that MF may have a future role in the treatment protocol of PCa whether as a monotherapy or in combination with other drugs.

Intake of Non-steroidal Anti-inflammatory Drugs and the Risk of Prostate Cancer: A Meta-Analysis

Background: Epidemiological evidences regarding the association between the use of non-steroidal anti-inflammatory drugs (NSAIDs) and the risk of prostate cancer (PC) is still controversial. Therefore, we conducted a meta-analysis to explore the controversy that exists.

Methods: Electronic databases including Medline, EMBASE, Web of Science, Cochrane Library, BIOSIS, Scopus, CBM, CNKI, WANFANG, and CQVIP were used to search for and identify eligible studies published until December 31, 2017. Pooled effect estimates for the relative risk (RR) were computed through fixed-effects or random-effects models as appropriate. Publication bias was evaluated by Egger's and Begg's tests and potential sources of heterogeneity were investigated in subgroup analyses.

Results: A total of 43 observational studies were eligible for this meta-analysis. A protective effect was identified for the intake of any NSAIDs on the risk of PC (pooled RR = 0.89, 95% CI = 0.81–0.98). Moreover, the long-term intake of NSAIDs (≥5 years rather than ≥4 years) was associated with reduced PC incidence (pooled RR = 0.882, 95% CI = 0.785–0.991). Aspirin intake was also associated with a 7.0% risk reduction of PC (pooled RR = 0.93, 95% CI = 0.89–0.96). The inverse association became stronger for advanced PC and PC with a Gleason score ≥7 compared to the association with total PC. Interestingly, it was the daily dose (≥1 pill/day) rather than, long-term aspirin intake (≥4 or ≥5 years) that was associated with reduced PC incidence (pooled RR = 0.875, 95% CI = 0.792–0.967). The pooled effects for non-aspirin NSAIDs demonstrated no significantly adverse or beneficial effects on total PC, advanced PC, or PC with Gleason score ≥7, though all pooled RRs were >1.

Conclusions: Our findings suggested a protective effect of the intake of any NSAIDs on the risk of PC, especially in those who took the NSAIDs for a long period. Moreover, aspirin intake was also associated with a decreased risk of PC, and there was a dose related association between aspirin intake and the risk of PC, while no significant effects of long-term aspirin intake were found on the PC incidence.

Aspirin Use and Lethal Prostate Cancer in the Health Professionals Follow-up Study

BACKGROUND

Aspirin use probably protects against some malignancies but its effects on lethal prostate cancer (PC) are unclear.

OBJECTIVE

To investigate the association between regular aspirin use and lethal PC.

DESIGN, SETTING, AND PARTICIPANTS

Participants were aged 40-75 yr at baseline in 1986 and have been followed with biennial questionnaires. The risk analysis includes 49 409 men. The survival analysis includes 5980 PC patients without metastatic disease at diagnosis.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We used Cox proportional hazards regression to examine the association between current, past, or never regular aspirin use (≥2 d/wk) in relation to lethal (metastatic or fatal) PC. We also examined years of use among current users and years since stopping among past users. In the risk analysis, aspirin was updated throughout follow-up. In the survival analysis, aspirin use after diagnosis was assessed.

RESULTS AND LIMITATIONS

Some 29% of participants used aspirin regularly at baseline, which increased to 60% by 2010. In the risk analysis, 804 men were diagnosed with lethal PC. Current regular aspirin was associated with a lower risk of lethal prostate cancer (hazard ratio [HR] 0.80, 95% confidence interval [CI] 0.66-0.96) compared to never users. In the survival analysis, 451 of the men diagnosed with nonmetastatic PC later developed lethal disease. Current postdiagnostic aspirin was associated with a lower risk of lethal PC (HR 0.80, 95% CI 0.64-1.00) and overall mortality (HR 0.79, 95% CI 0.69-0.90). When restricted to highly screened men, the risk analysis associations were stronger and survival analysis associations remained statistically significant. Reverse causation and residual confounding remain concerns, as demonstrated by the attenuated results in sensitivity analyses.

CONCLUSIONS

Regular aspirin use was associated with a lower risk of lethal PC. Postdiagnostic use was associated with better survival after diagnosis.

PATIENT SUMMARY

We found that it may be advisable for prostate cancer patients to take aspirin to improve their survival for both prostate cancer mortality and other mortality outcomes.

Effect of statins type on incident prostate cancer risk: a meta-analysis and systematic review

The aim of this study is to investigate the effect of statins type or even when grouping statins by hydrophilic or hydrophobic nature on prostate cancer risk. A literature search was performed without language restrictions using the databases of PubMed (1984.1-2015.3), MEDLINE (1984.1-2015.3), and EMBASE (1990.1-2015.3). Two independent reviewers appraised eligible studies and extracted data. Weighted averages were reported as relative risk (RR) with 95% confidence intervals (CI). Statistic heterogeneity scores were assessed with the standard Cochran's Q-test and I2 statistic. Publication bias was detected using the Begg's and Egger's tests. All statistical analyses were conducted by STATA version 10. Finally, fourteen studies were included in the meta-analysis. Both hydrophilic and hydrophobic statins showed no association with incidence of prostate cancer (RR = 1.00, 95% CI: 0.82-1.17; RR = 0.90, 95% CI: 0.73-1.08, respectively). Meanwhile, the risk of prostate cancer was not reduced in simvastatin (RR = 0.89, 95% CI: 0.72-1.05), pravastatin (RR = 1.02, 95% CI: 0.94-1.11), atorvastatin (RR = 0.89, 95% CI: 0.76-1.02), fluvastatin (RR = 0.99, 95% CI: 0.97-1.01), or lovastatin users (RR = 0.94, 95% CI: 0.79-1.08). The funnel plot showed that there was no publication bias. The results showed that statins had a neutral effect on prostate cancer risk; hydrophilic and hydrophobic statins as well as any subtype of statins did not affect the risk of prostate cancer.

Pharmacological Targeting of Cell Cycle, Apoptotic and Cell Adhesion Signaling Pathways Implicated in Chemoresistance of Cancer Cells

Chemotherapeutic drugs target a physiological differentiating feature of cancer cells as they tend to actively proliferate more than normal cells. They have well-known side-effects resulting from the death of highly proliferative normal cells in the gut and immune system. Cancer treatment has changed dramatically over the years owing to rapid advances in oncology research. Developments in cancer therapies, namely surgery, radiotherapy, cytotoxic chemotherapy and selective treatment methods due to better understanding of tumor characteristics, have significantly increased cancer survival. However, many chemotherapeutic regimes still fail, with 90% of the drug failures in metastatic cancer treatment due to chemoresistance, as cancer cells eventually develop resistance to chemotherapeutic drugs. Chemoresistance is caused through genetic mutations in various proteins involved in cellular mechanisms such as cell cycle, apoptosis and cell adhesion, and targeting those mechanisms could improve outcomes of cancer therapy. Recent developments in cancer treatment are focused on combination therapy, whereby cells are sensitized to chemotherapeutic agents using inhibitors of target pathways inducing chemoresistance thus, hopefully, overcoming the problems of drug resistance. In this review, we discuss the role of cell cycle, apoptosis and cell adhesion in cancer chemoresistance mechanisms, possible drugs to target these pathways and, thus, novel therapeutic approaches for cancer treatment.

Complex roles of the old drug aspirin in cancer chemoprevention and therapy

The nonsteroidal anti-inflammatory agent aspirin is widely used for preventing and treating cardiovascular and cerebrovascular diseases. In addition, epidemiologic evidences reveal that aspirin may prevent a variety of human cancers, while data on the association between aspirin and some kinds of cancer are conflicting. Preclinical studies and clinical trials also reveal the therapeutic effect of aspirin on cancer. Although cyclooxygenase is a well-known target of aspirin, recent studies uncover other targets of aspirin and its metabolites, such as AMP-activated protein kinase, cyclin-dependent kinase, heparanase, and histone. Accumulating evidence demonstrate that aspirin may act in different cell types, such as epithelial cell, tumor cell, endothelial cell, platelet, and immune cell. Therefore, aspirin acts on diverse hallmarks of cancer, such as sustained tumor growth, metastasis, angiogenesis, inflammation, and immune evasion. In this review, we focus on recent progress in the use of aspirin for cancer chemoprevention and therapy, and integratively analyze the mechanisms underlying the anticancer effects of aspirin and its metabolites. We also discuss mechanisms of aspirin resistance and describe some derivatives of aspirin, which aim to overcome the adverse effects of aspirin.

Associations between aspirin use and the risk of cancers: a meta-analysis of observational studies

Background

Epidemiological studies have clarified the potential associations between regular aspirin use and cancers. However, it remains controversial on whether aspirin use decreases the risk of cancers risks. Therefore, we conducted an updated meta-analysis to assess the associations between aspirin use and cancers.

Methods

The PubMed, Embase, and Web of Science databases were systematically searched up to March 2017 to identify relevant studies. Relative risks (RRs) with 95% confidence intervals (CIs) were used to assess the strength of associations.

Results

A total of 218 studies with 309 reports were eligible for this meta-analysis. Aspirin use was associated with a significant decrease in the risk of overall cancer (RR = 0.89, 95% CI: 0.87–0.91), and gastric (RR = 0.75, 95% CI: 0.65–0.86), esophageal (RR = 0.75, 95% CI: 0.62–0.89), colorectal (RR = 0.79, 95% CI: 0.74–0.85), pancreatic (RR = 0.80, 95% CI: 0.68–0.93), ovarian (RR = 0.89, 95% CI: 0.83–0.95), endometrial (RR = 0.92, 95% CI: 0.85–0.99), breast (RR = 0.92, 95% CI: 0.88–0.96), and prostate (RR = 0.94, 95% CI: 0.90–0.99) cancers, as well as small intestine neuroendocrine tumors (RR = 0.17, 95% CI: 0.05–0.58).

Conclusions

These findings suggest that aspirin use is associated with a reduced risk of gastric, esophageal, colorectal, pancreatic, ovarian, endometrial, breast, and prostate cancers, and small intestine neuroendocrine tumors.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4156-5) contains supplementary material, which is available to authorized users.

New therapeutic strategies to treat human cancers expressing mutant p53 proteins

The tumor suppressor p53 plays a critical role to preserve DNA fidelity from diverse insults through the regulation of cell-cycle checkpoints, DNA repair, senescence and apoptosis. The TP53 is the most frequently inactivated gene in human cancers. This leads to the production of mutant p53 proteins that loose wild-type p53 tumor suppression functions and concomitantly acquire new oncogenic properties among which deregulated cell proliferation, increased chemoresistance, disruption of tissue architecture, promotion of migration, invasion and metastasis and several other pro-oncogenic activities. Mouse models show that the genetic reconstitution of the wild type p53 tumor suppression functions rescues tumor growth. This strongly supports the notion that either restoring wt-p53 activity or inhibiting mutant p53 oncogenic activity could provide an efficient strategy to treat human cancers. In this review we briefly summarize recent advances in the study of small molecules and compounds that subvert oncogenic activities of mutant p53 protein into wt-p53 tumor suppressor functions. We highlight inhibitors of signaling pathways aberrantly modulated by oncogenic mutant p53 proteins as promising therapeutic strategies. Finally, we consider the clinical applications of compounds targeting mutant p53 and the use of currently available drugs in the treatment of tumors expressing mutant p53 proteins.

A stage-dependent link between metabolic syndrome components and incident prostate cancer

Metabolic syndrome is associated with increased cancer risk and progression at almost all sites, including the prostate in high-stage prostate cancer. However, several reports have described an inverse relationship between metabolic syndrome and its components and low-stage incident prostate cancer. Such anomalies in cancer research hamper efforts to fight cancer. Evidence suggests that metabolic syndrome and its components have two distinct effects in prostate cancer, concealing prostate cancer in low-stage disease and promoting progression to high-stage incident, nonlocalized, and lethal prostate cancer. The concealment of prostate cancer by metabolic syndrome and its components might be related to bias mechanisms that reduce PSA level and lead to a delayed diagnosis of low-stage prostate cancer, meaning that fewer men with metabolic syndrome are diagnosed with low-stage disease. The inverse link between metabolic syndrome and its components and low-stage incident prostate cancer might simply be the result of such bias and the shortcomings of the diagnostic procedure rather than being related to prostate cancer biology itself. The evidence summarized here supports the hypothesis that the link between metabolic syndrome and its components and incident prostate cancer is a two-way and stage-dependent one, a theory that requires further research.

The interplay between mutant p53 and the mevalonate pathway

Missense mutations in the TP53 gene lead to accumulation of dysfunctional TP53 proteins in tumors, showing oncogenic gain-of-function (GOF) activities. Stabilization of mutant TP53 (mutp53) is required for the GOF; however, the mechanisms by which mutp53 promotes cancer progression and how mutp53 stability is regulated are not completely understood. Recent work from our laboratory has identified statins, inhibitors of the mevalonate pathway, as degraders of conformational mutp53. Specific reduction of mevalonate-5-phosphate (MVP), a metabolic intermediate in the mevalonate pathway, by statins or mevalonate kinase (MVK) knockdown triggers CHIP ubiquitin ligase-mediated degradation of conformational mutp53 by inhibiting interaction between mutp53 and DNAJA1, a Hsp40 family member. Thus, the mevalonate pathway contributes to mutp53 stabilization. Given that mutp53 is shown to promote cancer progression by upregulating mRNA expression of mevalonate pathway enzymes by binding to the sterol regulatory element-binding protein 2 (SREBP2) and subsequently increasing activities of mevalonate pathway-associated oncogenic proteins (e.g., Ras, Rho, YAP/TAZ), there is a positive-feedback loop between mutp53 and the mevalonate pathway. Here, we summarize recent evidence linking the mevalonate pathway-mutp53 axis with cancer progression and further discuss the clinical relevance of this axis.

Metformin reduces all-cause mortality and diseases of ageing independent of its effect on diabetes control: A systematic review and meta-analysis

This systematic review investigated whether the insulin sensitiser metformin has a geroprotective effect in humans. Pubmed and Embase were searched along with databases of unpublished studies. Eligible research investigated the effect of metformin on all-cause mortality or diseases of ageing relative to non-diabetic populations or diabetics receiving other therapies with adjustment for disease control achieved. Overall, 260 full-texts were reviewed and 53 met the inclusion criteria. Diabetics taking metformin had significantly lower all-cause mortality than non-diabetics (hazard ratio (HR)=0.93, 95%CI 0.88-0.99), as did diabetics taking metformin compared to diabetics receiving non-metformin therapies (HR=0.72, 95%CI 0.65-0.80), insulin (HR=0.68, 95%CI 0.63-0.75) or sulphonylurea (HR=0.80, 95%CI 0.66-0.97). Metformin users also had reduced cancer compared to non-diabetics (rate ratio=0.94, 95%CI 0.92-0.97) and cardiovascular disease (CVD) compared to diabetics receiving non-metformin therapies (HR=0.76, 95%CI 0.66-0.87) or insulin (HR=0.78, 95%CI 0.73-0.83). Differences in baseline characteristics were observed which had the potential to bias findings, although statistical adjustments were made. The apparent reductions in all-cause mortality and diseases of ageing associated with metformin use suggest that metformin could be extending life and healthspans by acting as a geroprotective agent.

Regular Aspirin Use and the Risk of Lethal Prostate Cancer in the Physicians' Health Study

BACKGROUND

Regular aspirin use probably protects against some malignancies including prostate cancer (PC), but its impact on lethal PC is particularly unclear.

OBJECTIVE

To investigate the association between regular aspirin and (1) the risk of lethal PC in a large prospective cohort and (2) survival after PC diagnosis.

DESIGN, SETTING, AND PARTICIPANTS

In 1981/82, the Physicians' Health Study randomized 22 071 healthy male physicians to aspirin, β-carotene, both, or placebo. After the trial ended in 1988, annual questionnaires have obtained data on aspirin use, cancer diagnoses, and outcomes up to 2009 for the whole cohort, and to 2015 for PC patients.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We evaluated the relationship between regular aspirin (>3 tablets/week) and lethal PC (metastases or PC death). Cox proportional-hazards models estimated hazard ratios (HRs) for the risk of lethal PC in the whole cohort and postdiagnosis survival among men initially diagnosed with nonlethal PC.

RESULTS AND LIMITATIONS

Risk analysis revealed that 502 men developed lethal PC by 2009. Current and past regular aspirin was associated with a lower risk of lethal PC (current: HR 0.68, 95% confidence interval [CI] 0.52-0.89; past: HR 0.54, 95% CI 0.40-0.74) compared to never users. In the survival analysis, 407/3277 men diagnosed with nonlethal PC developed lethal disease by 2015. Current postdiagnostic aspirin was associated with lower risks of lethal PC (HR 0.68, 95% CI 0.52-0.90) and overall mortality (HR 0.72, 95% CI 0.61-0.9). We could not assess aspirin dose, and inconsistencies were observed in some sensitivity analyses.

CONCLUSIONS

Current regular aspirin use was associated with a lower risk of lethal PC among all participants. Current postdiagnostic use was associated with improved survival after diagnosis, consistent with a potential inhibitory effect of aspirin on PC progression. A randomized trial is warranted to confirm or refute these findings.

PATIENT SUMMARY

We examined the potential effect of regular aspirin use on lethal prostate cancer. We found that taking aspirin was associated with a lower risk of lethal prostate cancer, and taking it after diagnosis may help to prevent prostate cancer from becoming fatal.

Statins and Metformin Use Is Associated with Lower PSA Levels in Prostate Cancer Patients Presenting for Radiation Therapy

Background

A possible association between the level of prostate specific antigen (PSA) and the use of some commonly prescribed medications has been reported in recent studies. Most of these studies were carried out in general populations of men who were screened for prostate cancer using the PSA test. We reported on the association between the initial PSA level and the use of statins, metformin and alpha-blockers in patients who were diagnosed with prostate cancer and presented for radiation therapy.

Methods

Three hundred and eighty one patients treated between the years of 2000-2005 and 2009-2012 were included in this retrospective study. The information about statin, metformin and alpha-blockers use was recorded immediately prior to treatment. Differences in PSA levels prior to treatment by medication status were estimated using univa-riate and multivariate linear regression on log PSA values.

Results

Compared with men who were not on these medications, the PSA level at presentation was 20% lower for statin users (p = 0.002) and 33% lower for metformin users (p = 0.004). We did not observe statistically significant associations between the use of statins or metformin and cancer stage, National Comprehensive Cancer Network (NCCN) risk score, or therapy outcome. A statistically significant association between the NCCN risk score and the use of alpha-blockers was observed (p = 0.002).

Conclusions

We found that statins and metformin were associated with lower PSA levels in prostate cancer patients to an extent that could influence management decisions. We found no statistically significant associations between the use of these medications and treatment outcomes.

Use of statins offsets insulin-related cancer risk

AIM

There is firm evidence of a relation between type 2 diabetes (T2DM) and increased risks of cancer at various sites, but it is still unclear how different antihyperglycaemic therapies modify site-specific cancer risks. The aim of this study was to provide a complete characterization of all possible associations between individual T2DM therapies, statin use and site-specific cancers in the Austrian population.

METHODS

Medical claims data of 1 847 051 patients with hospital stays during 2006-2007 were used to estimate age- and sex-dependent co-occurrences of site-specific cancer diagnoses and treatment with specific glucose-lowering drugs and statins.

RESULTS

Patients treated with insulin or insulin secretagogues showed up to ninefold increased risks for cancers of the colon [males only (m)], liver (m), pancreas, lung (m) and brain (m), as well as a strongly decreased risk for prostate cancer (m). In patients taking statins, the risks were generally decreased, with a greater risk reduction in patients not receiving antihyperglycaemic therapies. The strongest effects were observed for use of insulin and pancreatic cancer [m: OR 4.5, 95% CI: 3.1-6.6; females (f): OR 4.2, 95% CI: 2.5-7.1], sulfonylureas (m: OR 2.8, 95% CI: 1.7-4.6; f: OR 3.0, 95% CI: 2.1-4.2) or glitazones and skin cancer (f: OR 0.54, 95% CI: 0.36-0.80), as well as metformin and cancer of the prostate (m: OR 0.82, 95% CI: 0.75-0.91) and corpus uteri (f: OR 1.7, 95% CI: 1.4-2.0) and non-Hodgkin's lymphoma (f: OR 0.76, 95% CI: 0.64-0.91).

CONCLUSIONS

The use of statins offsets insulin-related cancer risks in patients with diabetes independently of sex and age. Overall, our data support the hyperglycaemia-cancer hypothesis. A reduction in endogenous or exogenous hyperinsulinaemia may be beneficial for cancer prevention. Therefore, insulin-sparing and insulin-sensitizing drugs should be the preferred treatment choices.

Current and Emerging Uses of Statins in Clinical Therapeutics: A Review

Statins, a class of cholesterol-lowering medications that inhibit 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase, are commonly administered to treat atherosclerotic cardiovascular disease. Statin use may expand considerably given its potential for treating an array of cholesterol-independent diseases. However, the lack of conclusive evidence supporting these emerging therapeutic uses of statins brings to the fore a number of unanswered questions including uncertainties regarding patient-to-patient variability in response to statins, the most appropriate statin to be used for the desired effect, and the efficacy of statins in treating cholesterol-independent diseases. In this review, the adverse effects, costs, and drug–drug and drug–food interactions associated with statin use are presented. Furthermore, we discuss the pleiotropic effects associated with statins with regard to the onset and progression of autoimmune and inflammatory diseases, cancer, neurodegenerative disorders, strokes, bacterial infections, and human immunodeficiency virus. Understanding these issues will improve the prognosis of patients who are administered statins and potentially expand our ability to treat a wide variety of diseases.

A review for clinicians: Prostate cancer and the antineoplastic properties of metformin

OBJECTIVES

Metformin has numerous antineoplastic effects including an AMP-activated protein kinase-dependent mechanism, AMP-activated protein kinase-independent mechanisms, alteration of insulin and insulin-like growth factor signaling pathways, and suppression of androgen signaling pathways that trigger prostate cancer growth and proliferation. In contrast to other malignancies that are associated with increased incidence among patients with obesity and type II diabetes mellitus (T2DM), epidemiological studies suggest that obesity and T2DM may impart a protective effect on prostate cancer incidence by creating a set of metabolic conditions that lower androgen levels.

METHODS AND MATERIALS

The PubMed and Web of Science databases were searched using the terms "prostate cancer," "metformin," "antineoplastic," "antitumorigenic," and "diabetes" up to the first week of August 2016. Articles regarding metformin's antineoplastic properties on prostate cancer were reviewed.

RESULTS

Treating T2DM with metformin may reverse the metabolic conditions that suppress androgen levels, thereby enabling higher levels of androgens to stimulate prostate growth, proliferation, and tumorigenesis. Thus, the antineoplastic properties of metformin may not be appreciable in the early stages of prostate cancer development because metformin corrects for the metabolic conditions of T2DM that impart a protective effect on prostate cancer. These findings, although inconclusive, do not support the use of metformin as a preventive agent for prostate cancer. However, the future appears bright for metformin as either a monotherapy or an adjunct to androgen deprivation therapy, external-beam radiation therapy, prostatectomy, or chemotherapy. Support for this includes meta-analyses that suggest a mortality benefit to patients with prostate cancer on metformin, a clinical trial that demonstrates metformin leads to significant improvement in metabolic syndrome parameters for patients with prostate cancer on androgen deprivation therapy, and a clinical trial that shows metformin has modest activity in the treatment of some patients with asymptomatic or minimally symptomatic metastatic castration-resistant prostate cancer.

CONCLUSIONS

This review summarizes the literature regarding the antineoplastic mechanisms, clinical implications, and future trajectory of clinical research for metformin in prostate cancer.

The Relationship Between Metformin and Serum Prostate-Specific Antigen Levels

BACKGROUND

Metformin is the first-line oral antihyperglycemic of choice for individuals with type 2 diabetes. Recent evidence supports a role for metformin in prostate cancer chemoprotection. However, whether metformin indeed influences prostate biology is unknown. We aimed to study the association between metformin and serum prostate-specific antigen (PSA) levels-the primary prostate cancer biomarker.

METHODS

We conducted a cross-sectional study of 326 prostate cancer-free men with type 2 diabetes were recruited between 2004 and 2013 at St. Michael's Hospital. Men were excluded if they had a PSA ≥10-ng/ml, or used >2,550-mg/d metformin or supplemental androgens. Multivariate linear regressions quantified the association between metformin dose and log-PSA. Secondary analyses quantified the association between other antihyperglycemics (sulfonylureas, thiazolidinediones) and PSA; sensitivity analyses tested covariate interactions.

RESULTS

Median PSA was 0.9-ng/ml (IQR: 0.5-1.6-ng/ml). Metformin dose associated positively with BMI, HbA1c, diabetes duration, and number of statin, acetylsalicylic acid, diuretic users, and number of antihyperglycemics used, and negatively with LDL-C. In multivariate models, PSA changed by -8% (95%CI: -13 to -2%, P = 0.011) per 500-mg/d increase in metformin. Men with diabetes for ≥6 years (n = 163) saw a greater difference in PSA per 500-mg/d metformin (-12% [95% CI: -19 to -4%, P = 0.002], P-interaction = 0.018). Serum PSA did not relate with sulfonylureas, thiazolidinediones, or total number of antihyperglycemic agents used. Our findings are limited by the cross-sectional design of this study.

CONCLUSIONS

Metformin dose-dependently inversely associated with serum PSA, independent of other antihyperglycemic medications. Whether metformin confers a dose-dependent benefit on prostate tumorigenesis and progression warrants investigation. Prostate 76:1445-1453, 2016. © 2016 The Authors. The Prostate published by Wiley Periodicals, Inc.

The current evidence on statin use and prostate cancer prevention: are we there yet?

An increasing amount of data supports an inverse association between statin use and cancer risk. The findings for prostate cancer, particularly advanced disease, are the most promising of all cancers studied. Use of these agents seems to also be associated with improved prostate- cancer-specific survival, particularly in men undergoing radiotherapy, suggesting usefulness of statins in secondary and tertiary prevention. Some study results might be influenced by increased PSA screening and health-conscious behaviour in statin users but these factors are unlikely to completely account for observed beneficial effects. The epidemiological evidence is supported by preclinical studies that show that statins directly inhibit prostate cancer development and progression in cell-based and animal-based models. The antineoplastic effect of statins might arise from a number of cholesterol-mediated and non-cholesterol-mediated mechanisms that affect pathways essential for cancer formation and progression. Understanding these mechanisms is instrumental in drug discovery research for the development of future prostate cancer therapeutics, as well as in designing clinical trials to test a role for statins in prostate cancer prevention. Currently, sufficient data are lacking to support the use of statins for the primary prevention of prostate cancer and further research is clearly warranted. Secondary and tertiary prevention trials in men who have been diagnosed with prostate cancer might soon be performed.

Warfarin use and prostate cancer risk in the Finnish Randomized Study of Screening for Prostate Cancer

OBJECTIVE

Anticoagulants, especially vitamin K antagonists (VKAs) such as warfarin, have been hypothesized to have antitumor properties, and use of VKAs has been associated with a lower prostate cancer (PCa) risk. This study estimated PCa risk among users of warfarin and other anticoagulants.

MATERIALS AND METHODS

All anticoagulant use among 78,615 men during 1995-2009 was analyzed. Cox regression, adjusted for age, screening trial arm and use of other medications, with medication use as a time-dependent variable, was used to estimate PCa risk overall, and by tumor grade and stage.

RESULTS

In total, 6537 men were diagnosed with PCa during 1995-2009 (1210 among warfarin users). Compared to non-users, warfarin use was associated with an increased risk of PCa [multivariable-adjusted hazard ratio (HR) = 1.11, 95% confidence interval (CI) 1.01-1.22]. This was limited to short-term, low-dose use, and was not observed in long-term use. A similar overall risk increase was observed for Gleason grade 7-10 PCa. Low-dose, short-term use of warfarin was associated with an increased risk of metastatic PCa. However, the increase in risk vanished with continued use. Compared to other anticoagulants, low-dose use of warfarin was associated with a slightly elevated overall PCa risk (HR = 1.19, 95% CI 1.00-1.43). The increase in risk disappeared in long-term, high-dose use.

CONCLUSIONS

This study, which included a larger number of PCa cases with warfarin exposure than previous studies, does not support previous notions of decreased risk of PCa among warfarin users. A similar risk of PCa was found among warfarin users and the general population, and no difference in risk was found between warfarin and other anticoagulants.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Statin Use in Prostate Cancer: An Update

3-Hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors, known as statins, are commonly prescribed for the treatment of hypercholesterolemia and cardiovascular disease. A systematic review was conducted using the keywords “statin and prostate cancer” within the title search engines including PubMed, Web of Science, and the Cochrane Library for relevant research work published between 2004 and December 2015. Although still premature, accumulating clinical evidence suggests that statin use may be beneficial in the prevention and/or treatment of prostate cancer. These human studies consist of meta-analyses of secondary endpoints obtained from randomized, controlled cardiovascular disease clinical trials of statins, patient database, observational studies, and a few, small case–control studies, directly addressing statin use on prostate cancer pathology and recurrence. This review summarizes and discusses the recent clinical literature on statins and prostate cancer with a recommendation to move forward with randomized, placebo-controlled clinical trials, investigating the use of statins. Additional preclinical testing of statins on prostate cancer cell lines and in vivo models is needed to elucidate pathways and determine its efficacy for prevention and/or treatment of prostate cancer, more specifically, the difference in the effectiveness of lipophilic versus hydrophilic statins in prostate cancer.