Statins reduce the risk of pancreatic cancer in humans: a case-control study of half a million veterans

A proteomic signature and potential pharmacological opportunities in the adaptive resistance to MEK and PI3K kinase inhibition in pancreatic cancer cells

Pancreatic cancer is one of the most lethal cancer types and is becoming a leading cause of cancer-related deaths. The limited benefit offered by chemotherapy agents has propelled the search for alternative approaches that target specific molecular drivers of cancer growth and progression. Mutant KRas and effector pathways Raf/MEK/ERK and PI3K/Akt are key players in pancreatic cancer; however, preclinical studies have shown adaptive tumour response to combined MEK and PI3K kinase inhibition leading to treatment resistance. There is a critical unmet need to decipher the molecular basis underlying adaptation to this targeted approach. Here, we aimed to identify common protein expression alterations associated with adaptive resistance in KRas-mutant pancreatic cancer cells, and test if it can be overcome by selected already available small molecule drugs. We found a group of 14 proteins with common expression change in resistant cells, including KRas, caveolin-1, filamin-a, eplin, IGF2R and cytokeratins CK-8, -18 and -19. Notably, several proteins have previously been observed in pancreatic cancer cells with intrinsic resistance to the combined kinase inhibition treatment, suggesting a proteomic signature. We also found that resistant cells are sensitive to small molecule drugs ERK inhibitor GDC-0994, S6K1 inhibitor DG2 and statins.

An Update on Common Pharmaceuticals in the Prevention of Pancreatic Cancer

In this review, we aim to update readers about the most recent studies on common pharmaceuticals and their association with pancreatic cancer risk. The use of prophylactic aspirin, metformin, beta-blockers, and statins has been studied in the past but showed inconclusive results in the reduction of pancreatic cancer incidence. However, in recent studies, these medications along with combination therapy of aspirin and metformin were found to have a more significant association with decreasing risk. Given the poor prognosis of pancreatic cancer despite treatment, medication prophylaxis prevention should be considered. In this review, we hope to encourage future case-control or prospective studies on common medications that have shown great potential in delaying pancreatic cancer development.

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.

Beyond Lipid-Lowering: Effects of Statins on Cardiovascular and Cerebrovascular Diseases and Cancer

The 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, also known as statins, are administered as first-line therapy for hypercholesterolemia, both as primary and secondary prevention. Besides the lipid-lowering effect, statins have been suggested to inhibit the development of cardiovascular disease through anti-inflammatory, antioxidant, vascular endothelial function-improving, plaque-stabilizing, and platelet aggregation-inhibiting effects. The preventive effect of statins on atherothrombotic stroke has been well established, but statins can influence other cerebrovascular diseases. This suggests that statins have many neuroprotective effects in addition to lowering cholesterol. Furthermore, research suggests that statins cause pro-apoptotic, growth-inhibitory, and pro-differentiation effects in various malignancies. Preclinical and clinical evidence suggests that statins inhibit tumor growth and induce apoptosis in specific cancer cell types. The pleiotropic effects of statins on cardiovascular and cerebrovascular diseases have been well established; however, the effects of statins on cancer patients have not been fully elucidated and are still controversial. This review discusses the recent evidence on the effects of statins on cardiovascular and cerebrovascular diseases and cancer. Additionally, this study describes the pharmacological action of statins, focusing on the aspect of ‘beyond lipid-lowering’.

Statin Exposure and Pancreatic Cancer Incidence: A Japanese Regional Population-Based Cohort Study, the Shizuoka Study

Preclinical studies suggest that statins contribute to the prevention of pancreatic cancer; however, the results of epidemiologic studies are inconsistent. Furthermore, sufficient data are unavailable for the general population of Asia. Here, we conducted an observational study using a comprehensive patient-linked, longitudinal health insurance database comprising the records of 2,230,848 individuals residing in Shizuoka Prefecture, Japan, from April 2012 to September 2018. We included individuals older than 40 years with data for medical examinations and statin exposure (≥365 statin prescription days). To balance baseline characteristics between the statin exposure and statin nonexposure groups, we used inverse probability of treatment propensity score weighting method. We estimated hazard ratios for associations with pancreatic cancer using the Cox proportional hazards regression model. Among 2,230,848 individuals, we included 100,537 in the statin exposure group (24%) and 326,033 in the statin nonexposure group (76%). Among the statin exposure group (352,485 person-years) and the statin nonexposure group (1,098,463 person-years), 394 (1.12 per 1,000 person-years) and 1176 (1.07 per 1,000 person-years) developed pancreatic cancer, respectively (P = 0.464). After adjustments using inverse probability of treatment weighting, the statin exposure group was associated with a decreased incidence of pancreatic cancer (hazard ratio, 0.84; 95% confidence intervals, 0.72-0.99; P = 0.036). In conclusion, the current Japanese regional population-based cohort study shows that statin exposure was associated with a lower incidence of pancreatic cancer. PREVENTION RELEVANCE: This study may support the possible role of statins in preventing pancreatic cancer in the general population in Japan.

The Impact of Statin Therapy on the Survival of Patients with Gastrointestinal Cancer

Statins are 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors that may play an important role in the evolution of cancers, due to their effects on cancer cell metabolism. Statins affect several potential pathways, including cell proliferation, angiogenesis, apoptosis and metastasis. The number of trials assessing the putative clinical benefits of statins in cancer is increasing. Currently, there are several trials listed on the global trial identifier website clinicaltrials.gov. Given the compelling evidence from these trials in a variety of clinical settings, there have been calls for a clinical trial of statins in the adjuvant gastrointestinal cancer setting. However, randomized controlled trials on specific cancer types in relation to statin use, as well as studies on populations without a clinical indication for using statins, have elucidated some potential underlying biological mechanisms, and the investigation of different statins is probably warranted. It would be useful for these trials to incorporate the assessment of tumour biomarkers predictive of statin response in their design. This review summarizes the recent preclinical and clinical studies that assess the application of statins in the treatment of gastrointestinal cancers with particular emphasize on their association with cancer risk.

The Pivotal Role of the Dysregulation of Cholesterol Homeostasis in Cancer: Implications for Therapeutic Targets

Cholesterol plays an important role in cellular homeostasis by maintaining the rigidity of cell membranes, providing a medium for signaling transduction, and being converted into other vital macromolecules, such as sterol hormones and bile acids. Epidemiological studies have shown the correlation between cholesterol content and cancer incidence worldwide. Accumulating evidence has shown the emerging roles of the dysregulation of cholesterol metabolism in cancer development. More specifically, recent reports have shown the distinct role of cholesterol in the suppression of immune cells, regulation of cell survival, and modulation of cancer stem cells in cancer. Here, we provide a comprehensive review of the epidemiological analysis, functional roles, and mechanistic action of cholesterol homeostasis in regard to its contribution to cancer development. Based on the existing data, cholesterol homeostasis is identified to be a new key player in cancer pathogenesis. Lastly, we also discuss the therapeutic implications of natural compounds and cholesterol-lowering drugs in cancer prevention and treatment. In conclusion, intervention in cholesterol metabolism may offer a new therapeutic avenue for cancer treatment.

The association between use of statin or aspirin and pancreatic ductal adenocarcinoma: A nested case-control study in a Korean nationwide cohort

Background

Although several studies have suggested that aspirin and statins may help prevent pancreatic ductal adenocarcinoma (PDAC), this concept has been controversial. This study aimed to evaluate the association between use of statin or aspirin and PDAC in a nationwide large cohort.

Methods

In this nested case‐control study, we used data from a 12‐year nationwide longitudinal cohort in Korea. Cases with PDAC and controls who were matched to cases by age, sex, income, and index year at a 1:5 ratio were established. We used multivariate logistic regression analyses to identify the independent risk factors of PDAC.

Results

We identified a total of 827 patients with PDAC between 2007 and 2013, and included 4135 matched controls. Diabetes mellitus, chronic and acute pancreatitis, pancreatic cystic lesions, and cholelithiasis were independent risk factors for PDAC. Statin use (odds ratio [OR], 0.92; 95% confidence interval [CI] 0.76‐1.11; P = .344; adjusted OR [aOR], 0.70; 95% CI 0.56‐0.87; P = .001) was associated with a reduced risk of PDAC after correction of the confounding factors, but aspirin use (OR, 0.98; 95% CI 0.84‐1.15; P = .838; aOR 0.84; 95% CI 0.70‐1.01, P = .068) was not associated with PDAC. Among the patients with risk factors, both statin use (OR, 0.50; 95% CI 0.38‐0.66; P < .001; aOR, 0.62; 95% CI 0.45‐0.84; P = .002) and aspirin use (OR, 0.48; 95% CI 0.31‐0.67; P < .001; aOR 0.67; 95% CI 0.50‐0.89, P = .006) were associated with a reduced risk of PDAC.

Conclusion

This study suggests that statin use was associated with a reduced risk of PDAC incidence but aspirin use was not. Both statin use and aspirin use were associated a reduced risk of PDAC incidence for patients with risk factors.

Statin Use and Risk of Pancreatic Cancer: An Updated Meta-analysis of 26 Studies

OBJECTIVE

The aim of this study was to explore the relationship between statin use and the risk of pancreatic cancer.

METHODS

Electronic databases were searched to identify relevant studies published until January 2018. The pooled relative risks (RRs) and 95% confidence intervals (CIs) were calculated with random-effects model. Subgroup analyses and sensitivity analysis were also conducted. Cochran Q test and I(2) statistic were used to evaluate the heterogeneity.

RESULTS

Twenty-six studies were included that contained more than 3 million participants and 170,000 pancreatic cancer patients. The overall result demonstrated a significant decrease in pancreatic cancer risk with statin use (RR, 0.84; 95% CI, 0.73-0.97; P = 0.000; I(2) = 84.4%). In subgroup analyses, nonsignificant association was detected between long-term statin use and the risk of pancreatic cancer (RR, 0.98; 95% CI, 0.86-1.11; P = 0.718; I(2) = 0.0%). Meanwhile, there was nonsignificant association between the use of lipophilic statins and the risk of pancreatic cancer (RR, 0.98; 95% CI, 0.84-1.15; P = 0.853; I(2) = 27.2%). No publication bias was found in this meta-analysis.

CONCLUSIONS

The overall result of this meta-analysis supports the hypothesis that statins have a protective effect on pancreatic cancer. Furthermore, high-quality randomized clinical trials and cohort studies are needed to confirm these findings.

Total Serum Cholesterol and Pancreatic Cancer: A Nested Case-Control Study

BACKGROUND

Pancreatic cancer is the third leading cause of cancer-related death in the United States. Total serum cholesterol (TSC) may predict cancer risk, although its role independent of statins remains elusive. We examined the association between TSC and pancreatic cancer risk independent of statins.

METHODS

A nested case-control analysis was conducted among statin-naïve patients within The Health Improvement Network (THIN), a United Kingdom-based general practice database. Cases were >40 years old and diagnosed with pancreatic cancer after at least 6 months of follow-up. Controls were selected by incidence density sampling and matched by age, sex, practice site, and follow-up. Primary exposure was TSC (mmol/L) prior to index date. Conditional logistic regression estimated ORs for pancreatic cancer risk associated with TSC. Sensitivity analyses were conducted among nondiabetics.

RESULTS

Among 1,241 cases and 3,307 matched controls, an average 8% reduction was observed in pancreatic cancer risk per mmol/L increase in TSC [OR 0.92, 95% confidence interval (CI): 0.85-1.00; nondiabetics: OR 0.91, 95% CI: 0.83-0.99]. When TSC was measured at 12-month intervals prior to diagnosis, the OR between TSC and pancreatic cancer was 0.88 at 0 to 12 months (95% CI: 0.77-1.00; nondiabetics: OR 0.81, 95% CI: 0.68-0.96). No significant association was seen at subsequent discrete intervals before index date.

CONCLUSIONS

TSC is a significant predictor of short-term risk for pancreatic cancer. This risk increase associated with lower TSC was independent of statins.

IMPACT

TSC could serve as a biomarker for risk stratification, screening, and early diagnosis of pancreatic cancer in future clinical prediction models.

Statin use is associated to a reduced risk of pancreatic cancer: A meta-analysis

BACKGROUND

Previous studies investigating the association between statin use and pancreatic cancer (PDAC) risk for a possible chemopreventive effect gathered heterogeneous results.

AIMS

To conduct a systematic review and meta-analysis to clarify this association.

METHODS

Comprehensive literature search of articles published up to February 2018, including case-control (CC),cohort studies (C), randomized controlled trials (RCTs) assessing association between statin use and PDAC risk. Studies had to report odds ratio (OR)/relative risk (RR), estimates with 95% confidence interval (CI), or provide data for their calculation. Pooled ORs with 95%CIs were calculated using random effects model, publication bias through Begg and Mazumdar test and heterogeneity by I² value.

RESULTS

27 studies(13 CC, 9C, 5 RCTs) for a total population of 11,975 PDAC/3,433,175 controls contributed to the analysis. The overall pooled result demonstrated a reduced PDAC risk among statin users (OR 0.70; 95% CI 0.60-0.82; p < 0.0001), compared to non-users. Sensitivity analyses suggested the risk reduction to be more important in CC studies, studies conducted in Asia and Europe, in males and atorvastatin users. No publication bias found.

CONCLUSIONS

The present meta-analysis suggests that statin use is associated with an overall PDAC risk reduction of 30%. Further studies are needed to clarify the association.

The association between statin use and endometrial cancer survival outcome: A meta-analysis

BACKGROUND

Previous studies on the association between statin use and survival outcomes in gynecologic cancers have presented conflicting results. No independent studies to elucidate the association between statin use and survival outcomes of endometrial cancer (EC) have been conducted.

METHODS

To gather updated evidence, we carried out an extensive literature search on Medline (PubMed and OvidSP), Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), wanfang data, and Vip network to identify all potential studies on the effect of statins on the prognosis of endometrial carcinoma. The design and quality of all studies were evaluated, and a fixed-effects model was used to calculate pooled hazard ratios (HRs) for overall survival (OS) and disease-specific survival (DSS).

RESULTS

Of the 219 articles screened, 9 articles were eligible, including 8 articles and 1 abstract. A total of 5923 patients with endometrial cancer who used statins were identified. Statin use was related to increased overall survival (HR, 0.80; 95% confidence interval [CI], 0.66-0.95, without significant heterogeneity, I = 52%, P = .080). Statin users also had increased disease-specific survival (HR, 0.69; 95% CI, 0.61-0.79, I = 0.0%).

CONCLUSION

Statins are beneficial to the survival outcome of patients with endometrial cancer. The selection of statins as a 1st-line agent seems justified for endometrial carcinoma.

Statin use and pancreatic cancer risk in two prospective cohort studies

BACKGROUND

Statins, 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, are common lipid-lowering agents and may reduce the risk of several cancer types including pancreatic cancer. However, the association between statin use and pancreatic cancer risk has not been fully evaluated in prospective studies.

METHODS

We studied the association between statin use and incident pancreatic cancer in 113,059 participants from the prospective Nurses' Health Study and Health Professionals Follow-up Study. Statin use was self-reported via study questionnaires and updated biennially. Hazard ratios (HRs) and 95% confidence intervals (CIs) for incidence of pancreatic cancer were estimated using multivariable Cox proportional hazards models with adjustment for potential confounders.

RESULTS

In total, 583 participants developed incident pancreatic cancer during 1.4 million person-years of follow-up. No difference was identified in pancreatic cancer risk for regular versus non-regular statin users (multivariable-adjusted HR 0.98; 95% CI 0.82-1.16). There was no significant heterogeneity in the association of statin use with pancreatic cancer risk between the cohorts. Similarly, longer duration of regular statin use was not associated with decreased risk of pancreatic cancer (P_trend = 0.65). The results remained similar when we examined statin use status at baseline or accounting for 4-year latency period. We observed no statistically significant effect modification for the association of statin use with pancreatic cancer risk by body mass index, smoking status, or diabetes mellitus status (all P_interaction > 0.21).

CONCLUSIONS

Regular statin use was not associated with pancreatic cancer risk in two large prospective cohort studies in the U.S.

Evidence-based complementary treatment of pancreatic cancer: a review of adjunct therapies including paricalcitol, hydroxychloroquine, intravenous vitamin C, statins, metformin, curcumin, and aspirin

Despite new and exciting research and renewed optimism about future therapy, current statistics of survival from pancreatic cancer remains dismal. Patients seeking alternative or complementary treatments should be warned to avoid the hype and instead look to real science. A variety of relatively safe and inexpensive treatment options that have shown success in preclinical models and/or retrospective studies are currently available. Patients require their physicians to provide therapeutic guidance and assistance in obtaining and administrating these various therapies. Paricalcitol, an analog of vitamin D, has been shown by researchers at the Salk Institute for Biological Studies to break though the protective stroma surrounding tumor cells. Hydroxychloroquine has been shown to inhibit autophagy, a process by which dying cells recycle injured organelles and internal toxins to generate needed energy for survival and reproduction. Intravenous vitamin C creates a toxic accumulation of hydrogen peroxide within cancer cells, hastening their death. Metformin inhibits mitochondrial oxidative metabolism utilized by cancer stem cells. Statins inhibit not only cholesterol but also other factors in the same pathway that affect cancer cell growth, protein synthesis, and cell cycle progression. A novel formulation of curcumin may prevent resistance to chemotherapy and inhibit pancreatic cancer cell proliferation. Aspirin therapy has been shown to prevent pancreatic cancer and may be useful to prevent recurrence. These therapies are all currently available and are reviewed in this paper with emphasis on the most recent laboratory research and clinical studies.

Isoprenoids responsible for protein prenylation modulate the biological effects of statins on pancreatic cancer cells

Background

Statin treatment of hypercholesterolemia is accompanied also with depletion of the mevalonate intermediates, including farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP) necessary for proper function of small GTPases. These include Ras proteins, prevalently mutated in pancreatic cancer. In our study, we evaluated the effect of three key intermediates of the mevalonate pathway on GFP-K-Ras protein localization and the gene expression profile in pancreatic cancer cells after exposure to individual statins.

Methods

These effects were tested on MiaPaCa-2 human pancreatic cancer cells carrying a K-Ras activating mutation (G12C) after exposure to individual statins (20 μM). The effect of statins (atorvastatin, lovastatin, simvastatin, fluvastatin, cerivastatin, rosuvastatin, and pitavastatin) and mevalonate intermediates on GFP-K-Ras protein translocation was analyzed using fluorescence microscopy. The changes in gene expression induced in MiaPaCa-2 cells treated with simvastatin, FPP, GGPP, and their combinations with simvastatin were examined by whole genome DNA microarray analysis.

Results

All tested statins efficiently inhibited K-Ras protein trafficking from cytoplasm to the cell membrane of the MiaPaCa-2 cells. The inhibitory effect of statins on GFP-K-Ras protein trafficking was partially prevented by addition of any of the mevalonate pathway’s intermediates tested. Expressions of genes involved in metabolic and signaling pathways modulated by simvastatin treatment was normalized by the concurrent addition of FPP or GGPP. K-Ras protein trafficking within the pancreatic cancer cells is effectively inhibited by the majority of statins; the inhibition is eliminated by isoprenoid intermediates of the mevalonate pathway.

Conclusions

Our data indicate that the anticancer effects of statins observed in numerous studies to a large extent are mediated through isoprenoid intermediates of the mevalonate pathway, as they influence expression of genes involved in multiple intracellular pathways.

Electronic supplementary material

The online version of this article (10.1186/s12944-017-0641-0) contains supplementary material, which is available to authorized users.

The Role of Common Pharmaceutical Agents on the Prevention and Treatment of Pancreatic Cancer

Survival from pancreatic cancer remains poor. Conventional treatment has resulted in only marginal improvements in survival compared with survival in the previous several decades. Thus, considerable interest has emerged regarding the potential use of common pharmaceutical agents as chemopreventative and chemotherapeutic options. Aspirin, metformin, statins, β-blockers, and bisphosphonates have biologically plausible mechanisms to inhibit pancreatic neoplasia, whereas dipeptidyl-peptidase 4 inhibitors may promote it. Regardless, real-world epidemiological data remain inconclusive. This review examines the hypotheses, evidence, and current state of the literature for each of these medications and their potential roles in the prevention and treatment of pancreatic cancer.

Variability in statin-induced changes in gene expression profiles of pancreatic cancer

Statins, besides being powerful cholesterol-lowering drugs, also exert potent anti-proliferative activities. However, their anti-cancer efficacy differs among the individual statins. Thus, the aim of this study was to identify the biological pathways affected by individual statins in an in vitro model of human pancreatic cancer. The study was performed on a human pancreatic cancer cell line MiaPaCa-2, exposed to all commercially available statins (12 μM, 24 h exposure). DNA microarray analysis was used to determine changes in the gene expression of treated cells. Intracellular concentrations of individual statins were measured by UPLC (ultra performance liquid chromatography)-HRMS (high resolution mass spectrometer). Large differences in the gene transcription profiles of pancreatic cancer cells exposed to various statins were observed; cerivastatin, pitavastatin, and simvastatin being the most efficient modulators of expression of genes involved namely in the mevalonate pathway, cell cycle regulation, DNA replication, apoptosis and cytoskeleton signaling. Marked differences in the intracellular concentrations of individual statins in pancreatic cancer cells were found (>11 times lower concentration of rosuvastatin compared to lovastatin), which may contribute to inter-individual variability in their anti-cancer effects. In conclusion, individual statins exert different gene expression modulating effects in treated pancreatic cancer cells. These effects may be partially caused by large differences in their bioavailability. We report large differences in gene transcription profiles of pancreatic cancer cells exposed to various statins. These data correlate to some extent with the intracellular concentrations of statins, and may explain the inter-individual variability in the anti-cancer effects of statins.

Statins and pancreatic cancer

Pancreatic cancer remains among the most lethal cancers, despite ongoing advances in treatment for all stages of the disease. Disease prevention represents another opportunity to improve patient outcome, with metabolic syndrome and its components, such as diabetes, obesity and dyslipidemia, having been recognized as modifiable risk factors for pancreatic cancer. In addition, statins have been shown to potentially reduce pancreatic cancer risk and to improve survival in patients with a combination of metabolic syndrome and pancreatic cancer. Furthermore, preclinical studies have demonstrated that statins exhibit antitumor effects in pancreatic cancer cell lines in vitro and animal models in vivo, in addition to delaying the progression of pancreatic intraepithelial neoplasia to pancreatic ductal adenocarcinoma (PDAC) and inhibiting PDAC formation in conditional K-Ras mutant mice. The mechanisms by which statins produce anticancer effects remain poorly understood, although appear to involve inhibition of the mevalonate/cholesterol synthesis pathway, thus blocking the synthesis of intermediates important for prenylation and activation of the Ras/mitogen-activated protein kinase 1 signaling pathway. Furthermore, statins have been identified to modulate the phosphoinositide 3-kinase/Akt serine/threonine kinase 1 and inflammation signaling pathways, and to alter the expression of genes involved in lipid metabolism, which are important for PDAC growth and proliferation. In addition, statins have been demonstrated to exhibit further antitumor mechanisms in a number of other cancer types, which are beyond the scope of the present review. In the present review, current evidence highlighting the potential of statins as chemopreventive agents in pancreatic cancer is presented, and the antitumor mechanisms of statins elucidated thus far in this disease are discussed.

Simvastatin attenuates macrophage-mediated gemcitabine resistance of pancreatic ductal adenocarcinoma by regulating the TGF-β1/Gfi-1 axis

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy with an intrinsic resistance to almost all chemotherapeutic drugs, including gemcitabine. An abundance of tumor-associated macrophages (TAMs), which can promote the resistance of PDAC to gemcitabine, has been observed in the microenvironments of several tumors. In this study, we confirmed that incubation in TAM-conditioned medium (TAM-CM) reduces the gemcitabine-induced apoptosis of PDAC cells. Simvastatin attenuated the TAM-mediated resistance of PDAC cells to gemcitabine. Further investigation found that simvastatin reversed the TAM-mediated down-regulation of Gfi-1 and up-regulation of CTGF and HMGB1. Simvastatin induced Gfi-1 expression, which increased the sensitivity of PDAC cells to gemcitabine by decreasing TGF-β1 secretion by TAMs. A luciferase reporter assay and ChIP assay revealed that Gfi-1 directly repressed the transcription of CTGF and HMGB1. Simvastatin also reversed the effects of gemcitabine on the expression of TGF-β1 and Gfi-1 and reduced the resistance of PDAC to gemcitabine in vivo. These results provide the first evidence that simvastatin attenuates the TAM-mediated gemcitabine resistance of PDAC by blocking the TGF-β1/Gfi-1 axis. These findings suggest the TGF-β1/Gfi-1 axis as a novel therapeutic target for treating PDAC.

Concomitant Statin Use Has a Favorable Effect on Gemcitabine-Erlotinib Combination Chemotherapy for Advanced Pancreatic Cancer

PURPOSE

Erlotinib-gemcitabine combined chemotherapy is considered as the standard treatment for unresectable pancreatic cancer. This study aimed to determine the clinical factors associated with response to this treatment.

MATERIALS AND METHODS

This retrospective study included 180 patients with unresectable pancreatic cancer who received ≥2 cycles of gemcitabine-erlotinib combination therapy as first-line palliative chemotherapy between 2006 and 2014. "Long-term response" was defined as tumor stabilization after >6 chemotherapy cycles.

RESULTS

The median progression-free survival (PFS) and overall survival (OS) were 3.9 and 8.1 months, respectively. On univariate analysis, liver metastasis (p=0.023) was negatively correlated with long-term response. Locally advanced stage (p=0.017), a history of statin treatment (p=0.01), and carcinoembryonic antigen levels <4.5 (p=0.029) had a favorable effect on long-term response. On multivariate analysis, a history of statin treatment was the only independent favorable factor for long-term response (p=0.017). Prognostic factors for OS and PFS were significantly correlated with liver metastasis (p=0.031 and 0.013, respectively). A history of statin treatment was also significantly associated with OS after adjusting for all potential confounders (hazard ratio, 0.48; 95% confidence interval, 0.26-0.92; p=0.026).

CONCLUSION

These results suggest that statins have a favorable effect on "long-term response" to gemcitabine-erlotinib chemotherapy in unresectable pancreatic cancer patients. Statins may have a chemoadjuvant role in stabilizing long-term tumor growth.

Heme oxygenase is not involved in the anti-proliferative effects of statins on pancreatic cancer cells

Background

Pancreatic cancer is recognized as one of the most fatal tumors due to its aggressiveness and resistance to therapy. Statins were previously shown to inhibit the proliferation of cancer cells via various signaling pathways. In healthy tissues, statins activate the heme oxygenase pathway, nevertheless the role of heme oxygenase in pancreatic cancer is still controversial. The aim of this study was to evaluate, whether anti-proliferative effects of statins in pancreatic cancer cells are mediated via the heme oxygenase pathway.

Methods

In vitro effects of various statins and hemin, a heme oxygenase inducer, on cell proliferation were evaluated in PA-TU-8902, MiaPaCa-2 and BxPC-3 human pancreatic cancer cell lines. The effect of statins on heme oxygenase activity was assessed and heme oxygenase-silenced cells were used for pancreatic cancer cell proliferation studies. Cell death rate and reactive oxygen species production were measured in PA-TU-8902 cells, followed by evaluation of the effect of cerivastatin on GFP-K-Ras trafficking and expression of markers of invasiveness, osteopontin (SPP1) and SOX2.

Results

While simvastatin and cerivastatin displayed major anti-proliferative properties in all cell lines tested, pravastatin did not affect the cell growth at all. Strong anti-proliferative effect was observed also for hemin. Co-treatment of cerivastatin and hemin increased anti-proliferative potential of these agents, via increased production of reactive oxygen species and cell death compared to individual treatment. Heme oxygenase silencing did not prevent pancreatic cancer cells from the tumor-suppressive effect of cerivastatin or hemin. Cerivastatin, but not pravastatin, protected Ras protein from trafficking to the cell membrane and significantly reduced expressions of SPP1 (p < 0.05) and SOX2 (p < 0.01).

Conclusions

Anti-proliferative effects of statins and hemin on human pancreatic cancer cell lines do not seem to be related to the heme oxygenase pathway. While hemin triggers reactive oxygen species-induced cell death, cerivastatin targets Ras protein trafficking and affects markers of invasiveness.

Statins are Associated With a Reduced Risk of Brain Cancer: A Population-Based Case-Control Study

The aim of this study was to investigate whether statin utilization is associated with brain cancer risk.A population-based case-control study was conducted using nationally representative claims data from the National Health Insurance Bureau in Taiwan. Cases included all patients 50 years and older who received an index diagnosis of brain cancer between 2004 and 2011. Our controls were matched by age, sex, and index date. We estimated adjusted odds ratios (ORs) and 95% confidence intervals (CIs) using multiple logistic regression.We examined 213 brain cancer cases and 852 controls. The unadjusted ORs for any statin prescription was 0.77 (95% CI = 0.50-1.18) and the adjusted OR was 0.59 (95% CI = 0.37-0.96). Compared with no use of statins, the adjusted ORs were 0.68 (95% CI = 0.38-1.24) for the group having been prescribed with statins with cumulative defined daily dose (DDD) below 144.67 DDDs and 0.50 (95% CI = 0.28-0.97) for the group with the cumulative statin use of 144.67 DDDs or more.The results of this study suggest that statins may reduce the risk of brain cancer.

Prospective analysis of association between statins and pancreatic cancer risk in the Women's Health Initiative

PURPOSE

To determine whether HMG-CoA reductase inhibitors (statins) are associated with a lower risk of pancreatic cancer.

METHODS

The population included 160,578 postmenopausal women enrolled in the Women's Health Initiative (WHI) in which 385 incident cases of pancreatic cancer were identified over an average of 8.69 (SD ±4.59) years. All diagnoses were confirmed by medical record and pathology review. Information on statin use and other risk factors was collected at baseline and during follow-up. Multivariable-adjusted hazards ratios (HRs) and 95 % confidence intervals (CIs) evaluating the relationship between prior statin use (at baseline only as well as in a time-dependent manner) and risk of pancreatic cancer were computed from Cox proportional hazards regression analyses after adjusting for appropriate confounders. We also evaluated the effect of statin type, potency, lipophilic status, and duration of use. All statistical tests were two-sided.

RESULTS

Statins were used at baseline by 12,243 (7.5 %) women. The annualized rate of pancreatic cancer in statin users and nonusers, respectively, was 0.0298 versus 0.0271 %. The multivariable-adjusted HR for statin users versus nonusers at baseline was 0.92 and 95 % CI 0.57-1.48. In a time-dependent model, the HR for low-potency statins was 0.46, 95 % CI 0.20-1.04. There was no significant effect seen by statin lipophilicity or duration of use.

CONCLUSIONS

There was no significant relationship between statins and pancreatic cancer risk in the WHI; however, there was a marginal inverse association noted for low-potency statins. Analyses of larger numbers of cases are needed to further explore this relationship.

Statin and Metformin Use Prolongs Survival in Patients With Resectable Pancreatic Cancer

OBJECTIVES

The aim of this study was to investigate the impact of statin and metformin therapy on disease outcome for patients with pancreatic ductal adenocarcinoma (PDAC).

METHODS

This retrospective study included 171 PDAC patients who underwent surgical resection at the Stanford Cancer Institute between 1998 and 2013. No patients received neoadjuvant therapy. Statin and metformin use was defined as use during initial consult and continuing upon discharge from the hospital after surgery. Dose of each medication was recorded, as was the type of statin taken.

RESULTS

The median follow-up for all patients was 11.23 months (range, 0.2-105.0 months). Among the 171 patients included in our analysis, 18 patients (10.5%) took metformin and 34 patients (19.9%) took statins. Statin use was associated with better overall survival (OS) in patients with PDAC (P = 0.011). Metformin use was also associated with better OS (P = 0.035). The use of statins remained significant on multivariate analysis for OS (P = 0.014; hazards ratio, 0.33; 95% confidence interval, 0.139-0.799), but metformin use did not (P = 0.33; hazards ratio 0.60, 95% confidence interval, 0.211-1.675).

CONCLUSIONS

Statin and metformin use is associated with improved OS in patients with resectable PDAC. These medications should be further investigated for possible long-term use in the general population.

Increased lanosterol turnover: a metabolic burden for daunorubicin-resistant leukemia cells

The cholesterol metabolism is essential for cancer cell proliferation. We found the expression of genes involved in the cholesterol biosynthesis pathway up-regulated in the daunorubicin-resistant leukemia cell line CEM/R2, which is a daughter cell line to the leukemia cell line CCRF-CEM (CEM). Cellular (2)H2O labelling, mass spectrometry, and isotopomer analysis revealed an increase in lanosterol synthesis which was not accompanied by an increase in cholesterol flux or pool size in CEM/R2 cells. Exogenous addition of lanosterol had a negative effect on CEM/R2 and a positive effect on sensitive CEM cell viability. Treatment of CEM and CEM/R2 cells with cholesterol biosynthesis inhibitors acting on the enzymes squalene epoxidase and lanosterol synthase, both also involved in the 24,25-epoxycholesterol shunt pathway, revealed a connection of this pathway to lanosterol turnover. Our data highlight that an increased lanosterol flux poses a metabolic weakness of resistant cells that potentially could be therapeutically exploited.

Role of anti-stromal polypharmacy in increasing survival after pancreaticoduodenectomy for pancreatic ductal adenocarcinoma

AIM: To investigate the survival impact of common pharmaceuticals, which target stromal interactions, following a pancreaticoduodenectomy for pancreatic ductal adenocarcinoma.

METHODS: Data was collected retrospectively for 164 patients who underwent a pancreaticoduodenectomy for pancreatic ductal adenocarcinoma (PDAC). Survival analysis was performed on patients receiving the following medications: angiotensin-converting enzyme inhibitors (ACEI)/angiotensin II receptor blockers (ARB), calcium channel blockers (CCB), aspirin, and statins. Statistical analysis included Kaplan-meier survival estimates and cox multivariate regression; the latter of which allowed for any differences in a range of prognostic indicators between groups. Medications showing a significant survival benefit were investigated in combination with other medications to evaluate synergistic effects.

RESULTS: No survival benefit was observed with respect to ACEI/ARB (n = 41), aspirin or statins on individual drug analysis (n = 39). However, the entire CCB group (n = 26) showed a significant survival benefit on multivariate cox regression; hazard ratio (HR) of 0.475 (CI = 0.250-0.902, P = 0.023). Further analysis revealed that this was influenced by a group of patients who were taking aspirin in combination with CCB; median survival was significantly higher in the CCB + aspirin group (n = 15) compared with the group taking neither drug (n = 98); 1414 d vs 601 d (P = 0.029, log-rank test). Multivariate cox regression revealed neither aspirin nor CCB had a statistically significant impact on survival when given alone, however in combination the survival benefit was significant; HR = 0.332 (CI = 0.126-0.870, P = 0.025). None of the other medications showed a survival benefit in any combination.

CONCLUSION: Aspirin + CCB in combination appears to increase survival in patients with PDAC, highlighting the potential clinical use of combination therapy to target stromal interactions in pancreatic cancer.

Epidemiology of Pancreatic and Periampullary Cancer

Pancreatic cancer is an important public health problem, although infrequent but with an exceptionally high mortality rate worldwide. Given that the majority of cancers occur in association with smoking, diabetes, pancreatitis, genetic factors, and others and with a growing population worldwide in mind, more cases would be expected in the near future giving further impetus to investigating prevention and treatment strategies to this international issue. The representative data on epidemiology of carcinoma of pancreas in India and Nepal are very poor. While there are many questions to be resolved, it is apparent that many facets of pancreatic cancer are becoming increasingly understood, and prospects for prevention are becoming apparent. Hence, screening research, recommendations, and implementation is an obvious priority. Although previous studies have contributed to the knowledge of carcinoma of pancreas epidemiology, such association needs to be further verified with proper epidemiological work. A new and global approach to the study of carcinoma of pancreas epidemiology is required if the disease prevention and treatment strategies are to be adequately directed and supported in the coming years. The collection and analysis of epidemiologic carcinoma of pancreas data will play a critical role in guiding future disease prevention strategies and optimizing patient management.

Statins and the risk of pancreatic cancer in Type 2 diabetic patients--A population-based cohort study

The aim of this study was to determine whether statin use exerts a protective effect against pancreatic cancer in Type 2 diabetic patients. A retrospective population-based cohort study was designed to analyze the National Health Insurance Research database (NHIRD) from 1997-2010 in Taiwan. A total of 1,140,617 patients with a first-time diagnosis of Type 2 diabetes were enrolled. The event was defined as newly diagnosed pancreatic cancer. A Cox proportional hazards regression model with time-dependent covariates was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for risk of pancreatic cancer associated with statin use in the diabetic cohort. A total of 2,341 patients with newly diagnosed pancreatic cancer were identified in the diabetic cohort during the follow-up period of 6,968,217.1 person-years. In this cohort, 450,282 patients were defined as statin users (statin use ≥ 28 cumulative defined daily dose [cDDD] in 1 year) and 0.14% had pancreatic cancer; 690,335 patients were statin nonusers (statin use <28 cDDD in 1 year) and 0.25% had pancreatic cancer. Statin use significantly decreased the risk of pancreatic cancer (adjusted HRs: 0.78 in 28-83 cDDD per year; 0.48 in 84-180 cDDD per year; and 0.33 in >180 cDDD per year) after adjusting for multiple confounders. There was a significant dose-effect of statin use for the risk of pancreatic cancer (p for trend: <0.001). Statin use may be associated with a reduced risk of pancreatic cancer in Type 2 diabetic patients. More research is needed to clarify this association.

Interactions of the renin-angiotensin system in colorectal cancer and metastasis

The novel function of the renin-angiotensin system (RAS) is cardiovascular homeostasis. While the major active mediator angiotensin II (ANG II) produces most of the physiologic responses via angiotensin II type I receptor (AT1R), recent insights have looked at the implications of ANG II and its impact on solid tumor formation. Preclinical studies have demonstrated the direct effect of ANG II on the stimulation of angiogenesis via VEGF and other proliferative mediators. RAS components have thus been identified in numerous malignant tissues. Inhibition of the AT1R via angiotensin-converting enzyme inhibitors (ACE-Is) has demonstrated a decrease in solid tumor development and metastasis. Numerous retrospective analyses have demonstrated a reduction in colorectal cancer incidence, polyp formation, and distant metastasis in patients taking inhibitors of the RAS. The use of commonly prescribed anti-hypertensive medications as a chemo-preventative medication may have a remarkable impact in the colorectal cancer community. Further investigation and prospective clinical trials may provide further insight into the potentially beneficial use of ACE-Is and their impact on colorectal cancer.

Statin use and risk of pancreatic cancer: results from a large, clinic-based case-control study

BACKGROUND

Statins are cholesterol-lowering medications with pleiotropic effects, including alterations in growth signaling, as well as immunomodulatory and anti-inflammatory effects that may alter cancer risk. Evidence from previous epidemiologic studies is inconsistent about whether statin use is associated with a reduced risk of pancreatic cancer (PC).

METHODS

Patients with confirmed diagnoses of PC (cases) were recruited from medical and surgical oncology clinics, with controls (frequency-matched by sex and age) recruited from general medicine clinics, at a high-volume academic medical center over a 6-year period (2006-2011). Direct interviews were conducted with an epidemiological risk factor questionnaire covering topics such as medical history, lifestyle factors, and medication usage. Adjusted multivariable logistic regression was used to compute odds ratios (ORs) and 95% confidence intervals (CIs) as estimates of the relative risk of PC.

RESULTS

Data were obtained from 536 cases and 869 controls. Ever use of statins was associated with a 34% reduced PC risk (OR, 0.66; 95% CI, 0.47-0.92). In sex-stratified analyses, risk was statistically significantly reduced in men only (OR for men, 0.50; 95% CI, 0.32-0.79; OR for women, 0.86; 95% CI, 0.52-1.43). Duration of use was inversely associated with PC risk (>10-year use: overall OR, 0.51; OR for men, 0.41; 95% CI, 0.21-0.80; P(trend)  = .006).

CONCLUSIONS

This is the largest case-control study to demonstrate an inverse association between statin use and PC risk. Risk reduction in statin users appears to be sex-specific and is more pronounced in long-term users. Further research is warranted to better characterize this association and clarify the roles of underlying biologic mechanisms.

Statin treatment reduces the risk of hepatocellular carcinoma but not colon cancer-results from a nationwide case-control study in Sweden

BACKGROUND

Several studies have indicated that statins may have anticarcinogenic effects. The aim of the present study was to investigate if statin treatment was associated with a reduced risk of hepatocellular carcinoma (HCC) or colon cancer.

METHODS

A nationwide case-control study was carried out in which all cases of HCC and colon cancer in the Swedish population above 40 years of age between 1 July 2006 and 31 December 2010 were identified in the Swedish Cancer Register. For every case, five controls were selected and matched on age and sex. Data on statin use was extracted from the Swedish Prescribed Drug Register. We estimated risks using conditional logistic regression and adjusted for educational level, concomitant medications and comorbidity.

RESULTS

Identified were 3994 cases of HCC and matched with 19.970 controls, and 21.143 cases of colon cancer were identified and matched with 105.715 controls. In the adjusted analysis, the odds ratio (OR) for HCC among statin users was 0.88 (95% confidence interval (CI) 0.81-0.96), and the OR for colon cancer was 1.04 (95%CI 1.00-1.08) compared with non-users.

CONCLUSION

Statin use was associated with a modest decreased risk of HCC but did not influence the risk of colon cancer. Future randomized placebo-controlled trials in HCC high-risk patients are warranted to further investigate the possible prophylactic effect of statins in HCC.

[Statins and gastrointestinal cancers]

The antitumour effect of statins has already been proven in animal experiments and human cancer cell lines in several gastrointestinal cancers. The chemopreventive mechanism is not completely clarified but the enhancement of oxidative stress, increased autophagy, altered expression of pro- and antiproliferative proteins and their influence on intracellular signaling pathways may play a role. Randomized studies, however, failed to confirme the expected results obtained from experimental studies. The goal of this review is to summarize the data available in the literature regarding the chemopreventive effects of statins on several gastrointestinal cancers. Results of clinical trials suggest that 10-20 mg statin daily has no or minimal antitumour effect. Chemopreventive effect of hydrophilic statins could not be detected but it seems to be significant in the case of hydrophobic statins. There are only few data available on the long-term daily use of 30-40 mg statins. Further long-term evaluation of the effect of statins regarding gastrointestinal cancers is needed, and an analysis of compound- and dose-related subgroups would be beneficial. Chemoprevention with statins cannot yet be accepted as standard medical practice. Use of statins as chemopreventive agents cannot be a substitute for regular oncological screening or surveillance.

The differential effects of statins on the risk of developing pancreatic cancer: a case-control study in two centres in the United Kingdom

INTRODUCTION

There are plausible biological mechanisms for how statins may prevent pancreatic cancer, although the evidence from epidemiological studies in the general population is conflicting. This study aims to clarify whether statins exert their effects in specific sub-groups, namely, gender, smoking status and diabetes.

METHODS

A matched case-control study was conducted in patients diagnosed with pancreatic cancer, and a group of dermatology patients of similar ages and gender, diagnosed with basal cell carcinoma. Participants' medical records were reviewed for information on statin use prior to diagnosis. Odds ratios and 95 % CIs for the development of pancreatic cancer were estimated using conditional logistic regression. Subgroup analysis was performed in men, women, smokers and those with type 2 diabetes.

RESULTS

Two hundred fifty-two cases (median age 71 years, range 48-73 years, 51 % women) and 504 controls were identified, of which 23 % of cases were regular statin users versus 21 % of controls. In the general study population there was no association between pancreatic cancer and regular statin use (OR 0.82, 95 % CI 0.53-1.23, p = 0.33). However, in male smokers, regular statin use was associated with significantly reduced odds of pancreatic cancer compared to male smokers not prescribed a statin (OR 0.11, 95 % CI 0.01-0.96, p = 0.05). In patients with type 2 diabetes statins use was not associated with reduced odds (OR 0.92, 95 % CI 0.35-2.45, p = 0.80), with no gender effects.

CONCLUSIONS

In male smokers, statins may reduce the odds of pancreatic cancer. Statin use should be measured in aetiological studies of pancreatic cancer but analysed in specific sub-groups. Future work should investigate statins as chemopreventative agents in this high risk sub-group.

Beyond aspirin-cancer prevention with statins, metformin and bisphosphonates

Cancer risk reduction using pharmacological means is an attractive modern preventive approach that supplements the classical behavioural prevention recommendations. Medications that are commonly used by large populations to treat a variety of common, non-cancer-related, medical situations are an attractive candidate pool. This Review discusses three pharmacological agents with the most evidence for their potential as cancer chemopreventive agents: anti-hypercholesterolaemia medications (statins), an antidiabetic agent (metformin) and antiosteoporosis drugs (bisphosphonates). Data are accumulating to support a significant negative association of certain statins with cancer occurrence or survival in several major tumour sites (mostly gastrointestinal tumours and breast cancer), with an augmented combined effect with aspirin or other non-steroidal anti-inflammatory drugs. Metformin, but not other hypoglycaemic drugs, also seems to have some antitumour growth activity, but the amount of evidence in human studies, mainly in breast cancer, is still limited. Experimental and observational data have identified bisphosphonates as a pharmacological group that could have significant impact on incidence and mortality of more than one subsite of malignancy. At the current level of evidence these potential chemopreventive drugs should be considered in high-risk situations or using the personalized approach of maximizing individual benefits and minimizing the potential for adverse effects with the aid of pharmacogenetic indicators.

Simvastatin delay progression of pancreatic intraepithelial neoplasia and cancer formation in a genetically engineered mouse model of pancreatic cancer

BACKGROUND AND AIMS

Pancreatic cancer is among the most dismal of human malignancies. There are no chemopreventive strategies for pancreatic cancer or its precursor lesions, pancreatic intraepithelial neoplasia (PanINs). Recent evidence suggests that statins have potential chemopreventive abilities. In this study, we used a genetically engineered mouse model of pancreatic cancer to evaluate the chemopreventive potential of this drug.

METHODS

Simvastatin was injected i.p. in LsL-Kras(G12D); Pdx1-Cre or LsL-Kras(G12D);LsL-Trp53(R172H);Pdx1-Cre mice. After five months, animals were sacrificed. The effect of simvastatin was evaluated by histopathological analyses, immunostaining, and real-time PCR.

RESULTS

After five months of treatment, simvastatin was able to significantly delay progression of mPanINs in LsL-Kras(G12D); Pdx1-Cre mice. Furthermore, formation of invasive pancreatic cancer in LsL-Kras(G12D); LsL-Trp53(R172H); Pdx1-Cre transgenic mice was partially inhibited by simvastatin. Invasive murine pancreatic cancer was identified in 9 of 12 (75%) LsL-Kras(G12D); LsL-Trp53(R172H);Pdx1-Cre untreated control mice. In contrast, transgenic mice treated with Simvastatin, only 4 out of 10 (40%, p = 0.004) developed murine pancreatic cancer during the study. Using real-time PCR we found a significant up-regulation of Hmgcr as sign of blocking HMG-CoA reductase, a key enzyme in the cholesterol biosynthesis. This shows our ability to achieve effective pharmacologic levels of simvastatin during pancreatic cancer formation in vivo.

CONCLUSION

Using a transgenic mouse model that recapitulates human pancreatic cancer, this study provides first evidence that simvastatin is an effective chemopreventive agent by delaying the progression of PanINs and partially inhibit the formation of murine pancreatic cancer.

Clinical outcomes of chemotherapy for diabetic and nondiabetic patients with pancreatic cancer: better prognosis with statin use in diabetic patients

OBJECTIVES

The aim of this study was to clarify the impact of diabetes mellitus (DM) as well as antidiabetic, antihypertensive, and antihyperlipidemic medications such as metformin and statins on survival in patients with advanced pancreatic cancer receiving chemotherapy.

METHODS

We retrospectively reviewed the medical records of 250 patients with advanced pancreatic cancer receiving chemotherapy. Multivariate analyses of prognostic factors for survival were performed both in overall population and in subgroups with and without DM.

RESULTS

Diabetes mellitus was diagnosed in 124 patients (50%) who had less distant metastasis and more hypertension. Thirty patients received statin for hyperlipidemia. Overall survival was 13.3 versus 10.0 months with and without DM (P = 0.084), but hazard ratio of DM was 1.05 (P = 0.758) in the multivariate analysis. Subgroup analysis of diabetic patients, but not in non-diabetic patients, demonstrated use of statins (hazard ratio, 0.40; P = 0.010) as a prognostic factor, as well as distant metastasis, performance status, combination therapy with gemcitabine and S-1, and use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. No antidiabetic medications were prognostic factors.

CONCLUSIONS

Neither DM nor antidiabetic treatment had prognostic impact on advanced pancreatic cancer. Statin use was associated with better survival in the diabetic patients.

New-onset diabetes with a history of dyslipidemia predicts pancreatic cancer

OBJECTIVE

This study aimed to investigate whether the reported relationship between diabetes and pancreatic cancer (PC) could result from detection bias and whether dyslipidemia and/or new-onset diabetes (diagnosed within 1 year) could predict PC.

METHODS

A random sample of 1 million subjects covered by National Health Insurance was recruited. From 2003 to 2005, 495,493 men and 503,901 women without PC were followed up. Cox regression was used to evaluate the adjusted relative risk considering potential PC detection examinations and covariates.

RESULTS

Diabetic patients had a significantly higher probability of receiving examinations that might lead to PC diagnosis. In Cox proportional hazards regression models, diabetes was not a significant predictor, but dyslipidemia was significantly associated with an approximately 40% higher risk of PC. Age, living in more urbanized regions, and potential PC detection examinations were significant covariates. Patients with new-onset diabetes and previous dyslipidemia had a remarkably higher risk compared with those without either condition (relative risk [95% confidence interval], 2.512 [1.169-5.398]).

CONCLUSIONS

Dyslipidemia, but not diabetes, is a significant risk factor for PC. The link between diabetes and PC is likely due to confounders and detection bias. Patients with new-onset diabetes and a history of dyslipidemia are at an especially high risk of PC.

Involvement of inflammatory factors in pancreatic carcinogenesis and preventive effects of anti-inflammatory agents. Semin Immunopathol. 2013;35:203-227. [PMID: 22955327 DOI: 10.1007/s00281-012-0340-x]

Chronic inflammation is known to be a risk for many cancers, including pancreatic cancer. Heavy alcohol drinking and cigarette smoking are major causes of pancreatitis, and epidemiological studies have shown that smoking and chronic pancreatitis are risk factors for pancreatic cancer. Meanwhile, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) are elevated in pancreatitis and pancreatic cancer tissues in humans and in animal models. Selective inhibitors of iNOS and COX-2 suppress pancreatic cancer development in a chemical carcinogenesis model of hamsters treated with N-nitrosobis(2-oxopropyl)amine (BOP). In addition, hyperlipidemia, obesity, and type II diabetes are also suggested to be associated with chronic inflammation in the pancreas and involved in pancreatic cancer development. We have shown that a high-fat diet increased pancreatic cancer development in BOP-treated hamsters, along with aggravation of hyperlipidemia, severe fatty infiltration, and increased expression of adipokines and inflammatory factors in the pancreas. Of note, fatty pancreas has been observed in obese and/or diabetic cases in humans. Preventive effects of anti-hyperlipidemic/anti-diabetic agents on pancreatic cancer have also been shown in humans and animals. Taking this evidence into consideration, modulation of inflammatory factors by anti-inflammatory agents will provide useful data for prevention of pancreatic cancer.

Atorvastatin correlates with decreased risk of esophageal cancer: a population-based case-control study from Taiwan

OBJECTIVES

The aim of this study was to explore the association between the use of statins and esophageal cancer in Taiwan.

METHODS

We designed a case-control study using database from the Taiwan National Health Insurance program. In all, 549 patients (cases) aged 20 years or older diagnosed recently with esophageal cancer, from 2000 to 2009, and 2,196 subjects (controls) without esophageal cancer participated in this study. The association between esophageal cancer and the use of statins and other co-morbidities was measured.

RESULTS

After adjustment for covariates, multivariate logistic regression showed that patients with a cumulative duration of ≥ 12 months of using atorvastatin might have a reduced risk of esophageal cancer, compared with those who did not use statins (odds ratio [OR] 0.14, 95% confidence interval [CI] 0.04-0.56). The other statins could not show a significant association with esophageal cancer. Age (OR 1.01, 95% CI 1.00-1.01), alcoholism (OR 3.83, 95% CI 3.01-4.89), and esophageal diseases (OR 4.60, 95% CI 3.46-6.12) were independent factors significantly associated with esophageal cancer.

CONCLUSIONS

Use of atorvastatin ≥ 12 months may correlate with an 86% reduction of esophageal cancer risk.

Statins and the risk of cancer after heart transplantation

BACKGROUND

Although newer immunosuppressive agents, such as mTOR (mammalian target of rapamycin) inhibitors, have lowered the occurrence of malignancies after transplantation, cancer is still a leading cause of death late after heart transplantation. Statins may have an impact on clinical outcomes beyond their lipid-lowering effects. The aim of the present study was to delineate whether statin therapy has an impact on cancer risk and total mortality after heart transplantation.

METHODS AND RESULTS

A total of 255 patients who underwent heart transplantation at the University Hospital Zurich between 1985 and 2007 and survived the first year were included in the present study. The primary outcome measure was the occurrence of any malignancy; the secondary end point was overall survival. During follow-up, a malignancy was diagnosed in 108 patients (42%). The cumulative incidence of tumors 8 years after transplantation was reduced in patients receiving a statin (34% versus 13%; 95% confidence interval, 0.25-0.43 versus 0.07-0.18; P<0.003). Statin use was associated with improved cancer-free and overall survival (both P<0.0001). A Cox regression model that analyzed the time to tumor formation with or without statin therapy, adjusted for age, male sex, type of cardiomyopathy, and immunosuppressive therapy (including switch to mTOR inhibitors or tacrolimus), demonstrated a superior survival in the statin group. Statins reduced the hazard of occurrence of any malignancy by 67% (hazard ratio, 0.33; 95% confidence interval, 0.21-0.51; P<0.0001).

CONCLUSIONS

Although it is not possible to adjust for all potential confounders because of the very long follow-up period, this registry suggests that statin use is associated with improved cancer-free and overall survival after cardiac transplantation. These data will need to be confirmed in a prospective trial.

Therapeutic targeting of pancreatic cancer utilizing sigma-2 ligands

One major barrier in the development of pancreas cancer therapeutics is the selective delivery of the drugs to their cellular targets. We have previously developed several sigma-2 ligands and reported the discovery of a component of the receptor for these ligands. Several sigma-2 ligands have been shown to trigger apoptosis in pancreas cancer cells. More importantly, sigma-2 ligands are internalized rapidly by the cancer cells and are capable of delivering other small-molecule therapeutics. Here we review sigma-2 ligands and conjugates as a potential novel therapy suitable for investigation in patients with pancreatic cancer.

The pathobiological impact of cigarette smoke on pancreatic cancer development (review)

Despite extensive efforts, pancreatic cancer remains incurable. Most risk factors, such as genetic disposition, metabolic diseases or chronic pancreatitis cannot be influenced. By contrast, cigarette smoking, an important risk factor for pancreatic cancer, can be controlled. Despite the epidemiological evidence of the detrimental effects of cigarette smoking with regard to pancreatic cancer development and its unique property of being influenceable, our understanding of cigarette smoke-induced pancreatic carcinogenesis is limited. Current data on cigarette smoke-induced pancreatic carcinogenesis indicate multifactorial events that are triggered by nicotine, which is the major pharmacologically active constituent of tobacco smoke. In addition to nicotine, a vast number of carcinogens have the potential to reach the pancreatic gland, where they are metabolized, in some instances to even more toxic compounds. These metabolic events are not restricted to pancreatic ductal cells. Several studies show that acinar cells are also greatly affected. Furthermore, pancreatic cancer progenitor cells do not only derive from the ductal epithelial lineage, but also from acinar cells. This sheds new light on cigarette smoke-induced acinar cell damage. On this background, our objective is to outline a multifactorial model of tobacco smoke-induced pancreatic carcinogenesis.

Statin use and risk of pancreatic cancer: a meta-analysis

PURPOSE

Statins are commonly prescribed medications that potently reduce cholesterol levels and the risk of cardiovascular events. Preclinical studies suggested statins also possess cancer chemopreventive properties. However, the clinical studies provided contradictory results as to whether statins influence the risk of pancreatic cancer. Herein, we present this meta-analysis to assess the association between statin use and risk of pancreatic cancer.

METHODS

We conducted a comprehensive search up to August 2011 for the eligible studies. Pooled relative risk (RR) estimates and corresponding 95 % confidence intervals (CIs) were calculated using the inverse-variance-weighted random-effects model. Subgroup analyses were conducted where data were available. Heterogeneity was assessed by the Cochran's Q test and the I(2) statistic.

RESULTS

We included 16 studies that involving 1,692,863 participants and 7,807 pancreatic cancer cases. Pooled results only indicated a non-significant decrease of pancreatic cancer risk among all statin users (RR 0.89; 95 % CIs, 0.74-1.07). Similar results were obtained in the subgroup analyses of the long-term (more than 4 years) follow-up (RR 0.94, 0.81-1.08) and statin use (RR 0.97, 0.76-1.23), and a null association was found between lipophilic statin use and pancreatic cancer risk (RR 1.03, 0.92-1.16). No evidence of publication bias was observed in the present meta-analysis. However, significant heterogeneity was detected among all studies (p < 0.00001, I(2) = 81 %).

CONCLUSIONS

In conclusion, our results suggest that there is no association between statin use and pancreatic cancer risk, when statins are taken at daily doses for cardiovascular event prevention.

Statin-dependent activation of protein kinase Cδ in acute promyelocytic leukemia cells and induction of leukemic cell differentiation

Statins are HMG-CoA (3-hydroxy-3-methyl-glutaryl-coenzyme A) reductase inhibitors, which block the conversion of HMG-CoA to mevalonate and have potent cholesterol lowering properties. Beyond their importance in the generation of lipid lowering effects, the regulatory effects of statins on the mevalonate pathway have a significant impact on multiple other cellular functions. There is now extensive evidence that statins have anti-inflammatory and anti-neoplastic properties, but the precise mechanisms by which such responses are generated are not well understood. In the present study we demonstrate that statins engage a member of the protein kinase C (PKC) family of proteins, PKCδ, in acute promyelocytic leukemia (APL) cells. Our study shows that atorvastatin and fluvastatin induce proteolytic activation of PKCδ in the APL NB4 cell line, which expresses the t(15;17) translocation. Such engagement of PKCδ results in induction of its kinase domain and downstream regulation of pathways important for statin-dependent leukemia cell differentiation. Our research shows that the function of PKCδ is essential for statin-induced leukemic cell differentiation, as demonstrated by studies involving selective targeting of PKCδ using siRNAs. We also demonstrate that the potent enhancing effects of statins on all-trans retinoic acid (ATRA)-induced gene expression for CCL3 and CCL4 requires the function of PKCδ, suggesting a mechanism by which statins may promote ATRA-induced antileukemic responses. Altogether, our data establish a novel function for PKCδ as a mediator of statin-induced differentiation of APL cells and antileukemic effects.