Impact of statin use on survival in patients undergoing resection for early-stage pancreatic cancer

Unraveling the Anticancer Potential of Statins: Mechanisms and Clinical Significance

Statins are an essential medication class in the treatment of lipid diseases because they inhibit 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase. They reduce cholesterol levels and reduce the risk of cardiovascular disease in both primary and secondary prevention. In addition to their powerful pharmacologic suppression of cholesterol production, statins appear to have pleitropic effects in a wide variety of other diseases by modulating signaling pathways. In recent years, statins have seen a large increase in interest due to their putative anticancer effects. Statins appear to cause upregulation or inhibition in key pathways involved in cancer such as inhibition of proliferation, angiogenesis, and metastasis as well as reducing cancer stemness. Further, statins have been found to induce oxidative stress, cell cycle arrest, autophagy, and apoptosis of cancer cells. Interestingly, clinical studies have shown that statin use is associated with a decreased risk of cancer formation, lower cancer grade at diagnosis, reduction in the risk of local reoccurrence, and increasing survival in patients. Therefore, our objective in the present review is to summarize the findings of the publications on the underlying mechanisms of statins' anticancer effects and their clinical implications.

SQLE promotes pancreatic cancer growth by attenuating ER stress and activating lipid rafts-regulated Src/PI3K/Akt signaling pathway

Pancreatic cancer (PC), a highly lethal malignancy, commonly exhibits metabolic reprogramming that results in therapeutic vulnerabilities. Nevertheless, the mechanisms underlying the impacts of aberrant cholesterol metabolism on PC development and progression remain elusive. In this study, we found that squalene epoxidase (SQLE) is a crucial mediator of cholesterol metabolism in PC growth. We observed a profound upregulation of SQLE in PC tissues, and its high expression was correlated with poor patient outcomes. Our functional experiments demonstrated that SQLE facilitated cell proliferation, induced cell cycle progression, and inhibited apoptosis in vitro, while promoting tumor growth in vivo. Mechanistically, SQLE was found to have a dual role. First, its inhibition led to squalene accumulation-induced endoplasmic reticulum (ER) stress and subsequent apoptosis. Second, it enhanced de novo cholesterol biosynthesis and maintained lipid raft stability, thereby activating the Src/PI3K/Akt signaling pathway. Significantly, employing SQLE inhibitors effectively suppressed PC cell proliferation and xenograft tumor growth. In summary, this study reveals SQLE as a novel oncogene that promotes PC growth by mitigating ER stress and activating lipid raft-regulated Src/PI3K/Akt signaling pathway, highlighting the potential of SQLE as a therapeutic target for PC.

A Systematic Review and Meta-analysis on the Role of Statins in the Prevention of Mortality Following Pancreatic Cancer

BACKGROUND

Pancreatic cancer (PC) is a type of cancer with a high incidence and case-fatality rate.

OBJECTIVE

This study aimed to evaluate the role of statins in preventing mortality following PC based on scientific evidence with systematic review and meta-analysis method.

METHODS

This meta-analysis considered studies published from 1980 till the end of 2022 in ISI Web of Science, Scopus, PubMed, Cochrane, Science Direct, Google Scholar, and Embase databases. Funnel diagrams and Begg's and Egger's tests were used to assess the publication bias.

RESULTS

In general, this meta-analysis has included 19 studies (13 cohort studies, 4 case-control, and 2 randomized clinical trials (RCTs)) and a total of 100,888 patients with PC. The risk of mortality of PC in statin users in total was 0.86 (95% CI: 0.80 - 0.92, P-value <0.001); in the case-control studies, it was equal to 0.53 (0.34-0.83); in the cohort studies, it was equal to 0.87 (0.82-0.92, P-value <0.001); in RCTs, it was equal to 1.19 (0.99-1.42, P-value <0.001); in studies with good quality score category, it was equal to 0.92 (0.86-0.99, P-value <0.001), and in articles of the moderate quality score category, it was equal to 0.73 (0.64-0.84, P-value <0.001). The results of statistical tests indicated the existence of publication bias (Begg's test (P-value = 0.002) and Egger's test (P-value = 0.004)).

CONCLUSION

Statins reduce the risk of mortality in patients with PC. However, no significant relation has been observed in RCTs. Therefore, it is necessary to be cautious in interpreting the results.

Mutant p53 driven-LINC00857, a protein scaffold between FOXM1 and deubiquitinase OTUB1, promotes the metastasis of pancreatic cancer

Tumour metastasis is the major adverse factor for recurrence and death in pancreatic cancer (PC) patients. P53 mutations are considered to be the second most common type of mutation in PC and significantly promote PC metastasis. However, the molecular mechanisms underlying the effects of p53 mutations, especially the regulatory relationship of the protein with long noncoding RNAs (lncRNAs), remain unclear. In the present study, we demonstrated that the lncRNA LINC00857 exhibits a significantly elevated level in PC and that it is associated with poor prognosis; furthermore, TCGA data showed that LINC00857 expression was significantly upregulated in the mutant p53 group compared with the wild-type p53 group. Gain- and loss-of-function experiments showed that LINC00857 promotes the metastasis of PC cells. We further found that LINC00857 upregulates FOXM1 protein expression and thus accelerates metastasis in vitro and in vivo. Mechanistically, LINC00857 bound simultaneously to FOXM1 and to the deubiquitinase OTUB1, thereby serving as a protein scaffold and enhancing the interaction between FOXM1 and OTUB1, which inhibits FOXM1 degradation through the ubiquitin-proteasome pathway. Interestingly, we found that mutant p53 promotes LINC00857 transcription by binding to its promoter region. Finally, atorvastatin, a commonly prescribe lipid-lowering drug, appeared to inhibit PC metastasis by inhibiting the mutant p53-LINC00857 axis. Taken together, our results provide new insights into the biology driving PC metastasis and indicate that the mutant p53-LINC00857 axis might represent a novel therapeutic target for PC metastasis.

Aberrant Cholesterol Metabolism and Wnt/β-Catenin Signaling Coalesce via Frizzled5 in Supporting Cancer Growth

Frizzled (Fzd) proteins are Wnt receptors and play essential roles in development, homeostasis, and oncogenesis. How Wnt/Fzd signaling is coupled to physiological regulation remains unknown. Cholesterol is reported as a signaling molecule regulating morphogen such as Hedgehog signaling. Despite the elusiveness of the in-depth mechanism, it is well-established that pancreatic cancer specially requires abnormal cholesterol metabolism levels for growth. In this study, it is unexpectedly found that among ten Fzds, Fzd5 has a unique capacity to bind cholesterol specifically through its conserved extracellular linker region. Cholesterol-binding enables Fzd5 palmitoylation, which is indispensable for receptor maturation and trafficking to the plasma membrane. In Wnt-addicted pancreatic ductal adenocarcinoma (PDAC), cholesterol stimulates tumor growth via Fzd5-mediated Wnt/β-catenin signaling. A natural oxysterol, 25-hydroxylsterol competes with cholesterol and inhibits Fzd5 maturation and Wnt signaling, thereby alleviating PDAC growth. This cholesterol-receptor interaction and ensuing receptor lipidation uncover a novel mechanism by which Fzd5 acts as a cholesterol sensor and pivotal connection coupling lipid metabolism to morphogen signaling. These findings further suggest that cholesterol-targeting may provide new therapeutic opportunities for treating Wnt-dependent cancers.

Novel DZ-SIM Conjugate Targets Cancer Mitochondria and Prolongs Survival in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a disease with no effective therapeutics. We have developed a novel targeted therapy drug consisting of a tumor-targeting ligand, near-infrared (NIR) organic heptamethine carbocyanine dye (HMCD), and HMG-CoA inhibitor simvastatin (SIM), and assessed its efficacy in PDAC. PDAC cell specific targeting of DZ-SIM was measured by determining the fluorescence in cells and animals. Mitochondrial bioenergetics and functions were measured by Seahorse and flow cytometry, respectively. Apoptosis was assessed by DNA fragmentation, AnnexinV/Propidium Iodide staining, and TUNEL. Markers of cell invasion, epithelial-to-mesenchymal transition, and cancer stemness were measured. The effect of DZ-SIM on survival, tumor growth and metastasis was measured in the Krasþ/LSLG12D;Trp53þ/LSLR172H;Pdx-1-Cre (KPC) transgenic mice and in syngeneic and subcutaneous PDAC models. NIR fluorescence imaging showed specific localization of DZ-SIM to cancer, but not to normal cells and tissues. DZ-SIM significantly inhibited tumor growth and re-sensitized therapeutically resistant PDAC cells to conventional therapies. DZ-SIM killed cancer cells through unique pathways involving decreasing mitochondrial bioenergetics, including oxygen consumption and ATP production, and increasing ROS production. Mitochondrial depletion prevented the effect of DZ-SIM. Administration of DZ-SIM in 3 PDAC animal models resulted in a marked increase in survival and a decrease in tumor growth and metastasis.

Statin as a therapeutic agent in gastroenterological cancer

Statins inhibit 3-hydroxy-3-methylglutaryl-CoA reductase, the rate-limiting enzyme of the mevalonate pathway, and are widely used as an effective and safe approach handle hypercholesterolemia. The mevalonate pathway is a vital metabolic pathway that uses acetyl-CoA to generate isoprenoids and sterols that are crucial to tumor growth and progression. Multiple studies have indicated that statins improve patient prognosis in various carcinomas. Basic research on the mechanisms underlying the antitumor effects of statins is underway. The development of new anti-cancer drugs is progressing, but increasing medical costs from drug development have become a major obstacle. Readily available, inexpensive and well-tolerated drugs like statins have not yet been successfully repurposed for cancer treatment. Identifying the cancer patients that may benefit from statins is key to improved patient treatment. This review summarizes recent advances in statin research in cancer and suggests important considerations for the clinical use of statins to improve outcomes for cancer patients.

Idiopathic chronic pancreatitis: Beyond antioxidants

Chronic pancreatitis (CP) is a complex disease associated with gene-gene or gene-environment interactions. The incidence of idiopathic CP has shown an increasing trend, withits phenotypeshaving changed considerably in the last two decades. The diseaseitself can be regulated before it reaches the stage of established CP; however, the etiopathogenesis underlying idiopathic CP remains to be established, making the condition difficult to cure. Unfortunately, there also remains a lack of consensus regarding the beneficial effects of antioxidant therapiesfor CP. It is known that antioxidant therapy does not reduce inflammatory and fibrotic cytokines, making it unlikely that they could modulate the disease process. Although antioxidants are safe, very few studies to date have reported the long-term beneficial effects in patients with CP. Thus, studies are being performed to identify drugs that can improve symptoms and alter the natural history of CP. Statins, with their numerous pleiotropic effects, may play a role in the treatment of CP, butin 2006, their use was found to be associated with the undesirable side effect of promoting pancreatitis. Latter studies showed favourable effects of statins in CP, highlighting the particular benefits of lipophilic statins, such as lovastatin and simvastatin, over the hydrophilic statins, such as rosuvastatin. Ultimately, studies to repurpose N-acetylcysteine as a CP therapy areyielding very promising results.

Context Matters-Why We Need to Change From a One Size Fits all Approach to Made-to-Measure Therapies for Individual Patients With Pancreatic Cancer

Pancreatic cancer is one of the deadliest cancers and remains a major unsolved health problem. While pancreatic ductal adenocarcinoma (PDAC) is associated with driver mutations in only four major genes (KRAS, TP53, SMAD4, and CDKN2A), every tumor differs in its molecular landscape, histology, and prognosis. It is crucial to understand and consider these differences to be able to tailor treatment regimens specific to the vulnerabilities of the individual tumor to enhance patient outcome. This review focuses on the heterogeneity of pancreatic tumor cells and how in addition to genetic alterations, the subsequent dysregulation of multiple signaling cascades at various levels, epigenetic and metabolic factors contribute to the oncogenesis of PDAC and compensate for each other in driving cancer progression if one is tackled by a therapeutic approach. This implicates that besides the need for new combinatorial therapies for PDAC, a personalized approach for treating this highly complex cancer is required. A strategy that combines both a target-based and phenotypic approach to identify an effective treatment, like Reverse Clinical Engineering® using patient-derived organoids, is discussed as a promising way forward in the field of personalized medicine to tackle this deadly disease.

Biological Significance of YAP/TAZ in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal types of cancer. Despite major advances in defining the molecular mutations driving PDAC, this disease remains universally lethal with an overall 5-year survival rate of only about 7–8%. Genetic alterations in PDAC are exemplified by four critical genes (KRAS, TP53, CDKN2A, and SMAD4) that are frequently mutated. Among these, KRAS mutation ranges from 88% to 100% in several studies. Hippo signaling is an evolutionarily conserved network that plays a key role in normal organ development and tissue regeneration. Its core consists of the serine/threonine kinases mammalian sterile 20-like kinase 1 and 2 (MST1/2) and large tumor suppressor 1 and 2. Interestingly, pancreas-specific MST1/2 double knockout mice have been reported to display a decreased pancreas mass. Many of the genes involved in the Hippo signaling pathway are recognized as tumor suppressors, while the Hippo transducers Yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ) are identified as oncogenes. By dephosphorylation, YAP and TAZ accumulate in the nucleus and interact with transcription factors such as TEA domain transcription factor-1, 2, 3, and 4. Dysregulation of Hippo signaling and activation of YAP/TAZ have been recognized in a variety of human solid cancers, including PDAC. Recent studies have elucidated that YAP/TAZ play a crucial role in the induction of acinar-to-ductal metaplasia, an initial step in the progression to PDAC, in genetically engineered mouse models. YAP and TAZ also play a key role in the development of PDAC by both KRAS-dependent and KRAS-independent bypass mechanisms. YAP/TAZ have become extensively studied in PDAC and their biological importance during the development and progression of PDAC has been uncovered. In this review, we summarize the biological significance of a dysregulated Hippo signaling pathway or activated YAP/TAZ in PDAC and propose a role for YAP/TAZ as a therapeutic target.

Anti-tumor effect of statin on pancreatic adenocarcinoma: From concept to precision medicine

A statin is a cholesterol-lowering agent, which inhibits HMG-CoA (3-hydroxy-3-methylglutaryl-coenzyme A) reductase and subsequently reduces the cholesterol precursor, and was first used commercially in 1987. The concept of cholesterol restriction leading to cancer cell dysfunction was proposed in 1992. The interruption of different signaling pathways has been proved in preclinical experiments to elucidate the anti-tumor mechanism of statins in pancreatic adenocarcinoma. Observational studies have shown that the clinical use of statins is beneficial in patients with pancreatic adenocarcinoma, including a chemoprevention effect, post-surgical resection follow-up and therapeutic prognosis of advanced cancer stage. Arrest of the cancer cell cycle by the combined use of gemcitabine and statin was observed in a cell line study. The effect of microbiota on the tumor microenvironment of pancreatic adenocarcinoma is a new therapeutic approach as statins can modulate the gut microbiota. Hence, further randomized trials of statins in pancreatic adenocarcinoma treatment will be warranted with application of precision medicine from microbiota-derived, cell cycle-based and signaling pathway-targeted research.

Transcriptome sequencing analysis reveals unique and shared antitumor effects of three statins in pancreatic cancer

Statins, a class of commonly prescribed cholesterol‑lowering medications, have been revealed to influence the risk of multiple types of cancer. However, the antitumor effects of statins on pancreatic cancer and their differential efficacy among a variety of statins are not currently well‑defined. The aim of the present study was therefore to identify and compare the genes and related biological pathways that were affected by each individual statin on pancreatic cancer. Two human pancreatic cancer cell lines, MiaPaCa2 and PANC1, were exposed to three statins, lovastatin, fluvastatin and simvastatin. The inhibitory effect of statins on pancreatic cancer cell proliferation was first validated. Next, RNA‑seq analysis was used to determine the gene expression alterations in either low (2 µM) or high (20 µM) statin concentration‑treated cancer cells. Marked differences in gene transcription profiles of both pancreatic cancer cell lines exposed to high concentration statins were observed. Notably, the high concentration statins significantly suppressed core‑gene CCNA2‑associated cell cycle and DNA replication pathways and upregulated genes involved in ribosome and autophagy pathways. However, the low concentration statin‑induced gene expression alterations were only detected in MiaPaCa2 cells. In conclusion, a marked difference in the intra and inter cell‑type performance of pancreatic cancer cells exposed to a variety of statins at low or high concentrations was reported herein, which may provide insights for the potential clinical use of statins in future pancreatic cancer therapeutics.

Impact of statin use on cancer-specific mortality and recurrence: A meta-analysis of 60 observational studies

This meta-analysis mainly summarized the studies reporting an association between statin use and cancer-specific mortality and recurrence or progression of cancer patients.We systematically searched for studies about the statin used in cancer patients in electronic databases, including PubMed, Web of Science, Cochrane, Clinical Trials, from inception through the November 2019. A total of 60 studies which included 953,177 participants were eligible with 233,322 cancer patients used statin. Our analysis selected studies presented with outcome based on hazard ratios (HRs) and 95% confidence intervals (CIs) of cancer-specific mortality and cancer recurrence-free survival or progression-free survival. Heterogeneity between the studies was examined using I statistics, and sensitivity analyses were conducted to assess the robustness of the findings. All statistical analyses were performed using RevMan software (version 5.3).The use of statin was potentially associated with a decline in cancer-specific mortality in cancer patients (HR = 0.78; 95% CI: 0.74, 0.84; n = 39; I = 85%). Furthermore, statin use was associated with improved recurrence-free survival (HR = 0.87; 95% CI: 0.78,0.97; n = 23; I = 64%), but not with improvement in progression-free survival (HR = 1.05; 95% CI: 0.95,1.16; n = 14; I2 = 38%).The meta-analysis demonstrated that statin use could exhibit potential survival benefit in the prognosis of cancer patients. But our results are conservative for statins to improve disease recurrence and progression. These findings should be assessed in a prospective randomized cohort.

Statin use improves survival in patients with pancreatic ductal adenocarcinoma: A meta-analysis

BACKGROUND

Previous studies on statins' effect on survival of patients with pancreatic ductal adenocarcinoma (PDAC) report conflicting results.

AIMS

To evaluate the association between statin use and PDAC patients' survival.

METHODS

A systematic review and meta-analysis was performed including case-control, cohort studies and randomized controlled trials assessing the association between statin use and survival in PDAC patients. Pooled HRs with 95%CIs were calculated using random effects model; publication bias was assessed through Begg and Mazumdar test and heterogeneity by I2 value.

RESULTS

14 studies with 33,137 PDAC patients, 40% under statins, were included. Statins use was associated to a reduced death risk (HR 0.871; 95%CI: 0.819; 0.927; p = 0.0001) suggesting a protective effect, homogeneous for different geographic areas. This effect was significant in surgically resected patients (HR 0.50; 95%CI: 0.32; 0.76; p = 0.001) but not in those with advanced disease (HR 0.78; 95%CI: 0.59; 1.02; p = 0.07). In studies providing information on statin type, only rosuvastatin resulted associated to a reduced risk of death (HR 0.88; 95%CI: 0.81; 0.96; p = 0.004).

CONCLUSIONS

Statins use is significantly associated with a reduced risk of death in resected PDAC patients. This finding has to be considered with caution due to publication bias and the availability of only few studies for sensitivity analyses.

Simvastatin induces autophagic flux to restore cerulein-impaired phagosome-lysosome fusion in acute pancreatitis

BACKGROUND

During pancreatitis, autophagy is activated, but lysosomal degradation of dysfunctional organelles including mitochondria is impaired, resulting in acinar cell death. Retrospective cohort analyses demonstrated an association between simvastatin use and decreased acute pancreatitis incidence.

METHODS

We examined whether simvastatin can protect cell death induced by cerulein and the mechanisms involved during acute pancreatitis. Mice were pretreated with DMSO or simvastatin (20 mg/kg) for 24 h followed by 7 hourly cerulein injections and sacrificed 1 h after last injection to harvest blood and tissue for analysis.

RESULTS

Pancreatic histopathology revealed that simvastatin reduced necrotic cell death, inflammatory cell infiltration and edema. We found that cerulein triggered mitophagy with autophagosome formation in acinar cells. However, autophagosome-lysosome fusion was impaired due to altered levels of LAMP-1, AMPK and ULK-1, resulting in autophagosome accumulation (incomplete autophagy). Simvastatin abrogated these effects by upregulating LAMP-1 and activating AMPK which phosphorylated ULK-1, resulting in increased formation of functional autolysosomes. In contrast, autophagosomes accumulated in control group during pancreatitis. The effects of simvastatin to promote autophagic flux were inhibited by chloroquine. Mitochondria from simvastatin-treated mice were resistant to calcium overload compared to control, suggesting that simvastatin induced mitochondrial quality control to eliminate susceptible mitochondria. Clinical specimens showed a significant increase in cell-free mtDNA in plasma during pancreatitis compared to normal controls. Furthermore, genetic deletion of parkin abrogated the benefits of simvastatin.

CONCLUSION

Our findings reveal the novel role of simvastatin in enhancing autophagic flux to prevent pancreatic cell injury and pancreatitis.

Cholesterol depletion sensitizes gallbladder cancer to cisplatin by impairing DNA damage response

Gallbladder cancer (GBC) is the common malignancy of the bile tract system with extremely poor clinical outcomes, owing to its metastatic property and intrinsic resistance to the first-line drugs. Although it is well-established that cholesterol abnormity contributes to gallstone formation, a leading risk factor for GBC, the link of cholesterol homeostasis with GBC has not been investigated. The present study systematically examined the genes implicated in cholesterol homeostasis, and revealed altered gene expressions of de novo cholesterol biosynthesis and sterol sulfonation (SULT2B1), reduced bile acid synthesis (CYP7B1 and CYP39A1) and impaired sterol efflux (ABCA1, ABCG5, LCAT, and CETP) in GBC tissues. Suppression of cholesterol biosynthesis by lovastatin inhibited GBC cell proliferation possibly through attenuating the DNA repair process. Further investigation revealed lovastatin sensitized GBC cells to cisplatin-induced apoptosis and suppressed the activation of CHK1, CHK2, and H2AX during DNA damage response. By using chemically distinct statins, HMGCR depletion or supplementing mevalonate, the product of HMGCR, we showed the inhibitory effects on DNA repair process of lovastatin were due to the blockage of the mevalonate pathway. Subcutaneous xenograft mice model suggested lovastatin promoted the therapeutic efficacy of cisplatin, and significantly prolonged the survival times of tumor-bearing mice. Moreover, HMGCR ablation repressed tumor growth in vivo, which can be rescued partially by restored expression of HMGCR, suggesting the on-target effects of lovastatin. Therefore, our study provides the clinical relevance of cholesterol homeostasis with GBC progression, and highlights a novel intervention of combined use of lovastatin and cisplatin for GBC.

Obesity-Induced Adipose Tissue Inflammation as a Strong Promotional Factor for Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is expected to soon become the second leading cause of cancer related deaths in the United States. This may be due to the rising obesity prevalence, which is a recognized risk factor for PDAC. There is great interest in deciphering the underlying driving mechanisms of the obesity–PDAC link. Visceral adiposity has a strong correlation to certain metabolic diseases and gastrointestinal cancers, including PDAC. In fact, our own data strongly suggest that visceral adipose tissue inflammation is a strong promoter for PDAC growth and progression in a genetically engineered mouse model of PDAC and diet-induced obesity. In this review, we will discuss the relationship between obesity-associated adipose tissue inflammation and PDAC development, with a focus on the key molecular and cellular components in the dysfunctional visceral adipose tissue, which provides a tumor permissive environment.

Lipophilic statins inhibit YAP nuclear localization, co-activator activity and colony formation in pancreatic cancer cells and prevent the initial stages of pancreatic ductal adenocarcinoma in KrasG12D mice

We examined the impact of statins on Yes-associated Protein (YAP) localization, phosphorylation and transcriptional activity in human and mouse pancreatic ductal adenocarcinoma (PDAC) cells. Exposure of sparse cultures of PANC-1 and MiaPaCa-2 cells to cerivastatin or simvastatin induced a striking re-localization of YAP from the nucleus to the cytoplasm and inhibited the expression of the YAP/TEAD-regulated genes Connective Tissue Growth Factor (CTGF) and Cysteine-rich angiogenic inducer 61 (CYR61). Statins also prevented YAP nuclear import and expression of CTGF and CYR61 stimulated by the mitogenic combination of insulin and neurotensin in dense culture of these PDAC cells. Cerivastatin, simvastatin, atorvastatin and fluvastatin also inhibited colony formation by PANC-1 and MiaPaCa-2 cells in a dose-dependent manner. In contrast, the hydrophilic statin pravastatin did not exert any inhibitory effect even at a high concentration (10 μM). Mechanistically, cerivastatin did not alter the phosphorylation of YAP at Ser¹²⁷ in either PANC-1 or MiaPaCa-2 cells incubated without or with neurotensin and insulin but blunted the assembly of actin stress fiber in these cells. We extended these findings with human PDAC cells using primary KC and KPC cells, (expressing KrasG12D or both KrasG12D and mutant p53, respectively) isolated from KC or KPC mice. Using cultures of these murine cells, we show that lipophilic statins induced striking YAP translocation from the nucleus to the cytoplasm, inhibited the expression of Ctgf, Cyr61 and Birc5 and profoundly inhibited colony formation of these cells. Administration of simvastatin to KC mice subjected to diet-induced obesity prevented early pancreatic acini depletion and PanIN formation. Collectively, our results show that lipophilic statins restrain YAP activity and proliferation in pancreatic cancer cell models in vitro and attenuates early lesions leading to PDAC in vivo.

Central role of Yes-associated protein and WW-domain-containing transcriptional co-activator with PDZ-binding motif in pancreatic cancer development

Pancreatic ductal adenocarcinoma (PDAC) remains a deadly disease with no efficacious treatment options. PDAC incidence is projected to increase, which may be caused at least partially by the obesity epidemic. Significantly enhanced efforts to prevent or intercept this cancer are clearly warranted. Oncogenic KRAS mutations are recognized initiating events in PDAC development, however, they are not entirely sufficient for the development of fully invasive PDAC. Additional genetic alterations and/or environmental, nutritional, and metabolic signals, as present in obesity, type-2 diabetes mellitus, and inflammation, are required for full PDAC formation. We hypothesize that oncogenic KRAS increases the intensity and duration of the growth-promoting signaling network. Recent exciting studies from different laboratories indicate that the activity of the transcriptional co-activators Yes-associated protein (YAP) and WW-domain-containing transcriptional co-activator with PDZ-binding motif (TAZ) play a critical role in the promotion and maintenance of PDAC operating as key downstream target of KRAS signaling. While initially thought to be primarily an effector of the tumor-suppressive Hippo pathway, more recent studies revealed that YAP/TAZ subcellular localization and co-transcriptional activity is regulated by multiple upstream signals. Overall, YAP has emerged as a central node of transcriptional convergence in growth-promoting signaling in PDAC cells. Indeed, YAP expression is an independent unfavorable prognostic marker for overall survival of PDAC. In what follows, we will review studies implicating YAP/TAZ in pancreatic cancer development and consider different approaches to target these transcriptional regulators.

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.

Statin treatment and outcomes of metastatic pancreatic cancer: a pooled analysis of two phase III studies

BACKGROUND

The current analysis aims to evaluate the impact of statin co-treatment on the survival of patients with metastatic pancreatic cancer.

METHODS

This is a pooled analysis of de-identified patient data from two clinical trials (NCT01124786; NCT00844649). Overall and progression-free survival according to patient subsets (patients who received or who did not receive statins) were assessed through Kaplan-Meier analysis and log-rank test. Univariate and multivariate Cox regression analysis was performed to evaluate different factors potentially affecting overall and progression-free survival. Propensity score matching was performed to address heterogeneity in baseline characteristics of different subgroups of patients.

RESULTS

A total of 797 patients were assessed in the current study; of which 156 patients received statins and 641 did not receive statins. Using Kaplan-Meier survival estimates, patients who received statins seem to have better overall and progression-free survival compared to patients who did not (P = 0.008; P < 0.001, respectively). In multivariate analysis for factors affecting overall survival, the following factors were associated with worse overall survival: worse performance status (P < 0.001), no statin use (P = 0.044) and multiple sites of metastatic disease (P = 0.023); likewise in multivariate analysis for factors affecting progression-free survival, the following factors were associated with worse progression-free survival: worse performance status (P < 0.001), gemcitabine elaidate chemotherapy (P = 0.015) and no statin use (P = 0.048). Following propensity score matching and using Kaplan-Meier estimates, statin use was also associated with better overall and progression-free survival (P = 0.005; P = 0.040, respectively).

CONCLUSION

Statin use seems to be associated with better overall survival among patients with metastatic pancreatic cancer treated with first-line chemotherapy. Prospective studies designed specifically to assess this potential effect of statins are needed.

Targeting Tumor Metabolism With Statins During Treatment for Advanced-stage Pancreatic Cancer

INTRODUCTION

A growing body of preclinical data suggests that statins may exert potent antitumor effects, yet the interactions of these medications with standard therapies and clinical outcomes in this population is less clear. We assessed the impact of statin use on outcomes in patients with advanced-stage pancreatic adenocarcinoma undergoing various treatments.

MATERIALS AND METHODS

After institutional review board approval, we conducted a retrospective-cohort study consisting of 303 newly diagnosed advanced-stage pancreatic adenocarcinoma patients to determine the impact of statin use on outcomes. Univariate and multivariable Cox proportional hazard regression models were utilized to estimate hazard ratios (HRs). Time-to-event was estimated using Kaplan-Meier survival analysis for overall survival, distant metastasis, and locoregional failure. Baseline and active statin usage were assessed and to mitigate risk of immortal time bias, subanalysis excluding patients with under 6 months of follow-up was conducted.

RESULTS

Both prior (P=0.021) and active (P=0.030) statin usage correlated with improved survival in this cohort. Surgery, chemoradiation, and statin use improved 2-year survival rates (84.1% vs. 55.0%; P<0.001). On multivariable analysis, statin exposure was associated with overall survival (HR, 0.662; P=0.027) and trended to significance for freedom from distant metastasis (HR, 0.577; P=0.060). Comorbid conditions were not significantly associated with outcomes.

CONCLUSIONS

Statin use was associated with improved overall survival in advanced-stage pancreatic adenocarcinoma patients. This data supports previous findings in early-stage pancreatic adenocarcinoma and other cancer sites. To our knowledge this is the first report to examine the efficacy of statin use as a supplementary treatment option in advanced-stage pancreatic adenocarcinoma patients.

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.

Prediagnosis Use of Statins Associates With Increased Survival Times of Patients With Pancreatic Cancer

BACKGROUND & AIMS

Statin medications, most commonly prescribed to reduce lipid levels and prevent cardiovascular disease, may be associated with longer survival times of patients with cancer. However, the association of statins with outcomes of patients with pancreatic adenocarcinoma is not clear.

METHODS

We analyzed the association of statin use before a diagnosis of pancreatic cancer with survival times of 648 participants in the Nurses' Health Study and Health Professionals Follow-up Study who were diagnosed with pancreatic adenocarcinoma from 2000 through 2013. We estimated hazard ratios (HRs) for overall mortality using Cox proportional hazards models with adjustment for potential confounders. We assessed the temporal association between prediagnosis statin use and cancer survival by 2-year lag periods to account for a possible latency period between statin use and cancer survival.

RESULTS

Regular statin use before diagnosis of pancreatic cancer was associated with modestly prolonged survival compared with nonregular use (adjusted HR, 0.82; 95% CI, 0.69-0.97; P = .02). A 1-month longer median survival was observed in regular statin users compared with nonregular users. Regular statin use within the 2 years prior to cancer diagnosis was most strongly associated with longer survival. We observed no statistically significant effect modification by smoking status, body mass index, diabetes, or cancer stage (all Pinteraction > .53). Regular statin use before diagnosis was similarly associated with survival in the Nurses' Health Study (HR, 0.79; 95% CI, 0.64-0.97) and Health Professionals Follow-up Study (HR, 0.86; 95% CI, 0.63-1.15).

CONCLUSIONS

Regular statin use before diagnosis of pancreatic cancer was associated with modest increases in survival times in 2 large prospective cohort studies.

Effect of Metformin and Statin Use on Survival in Pancreatic Cancer Patients: a Systematic Literature Review and Meta-analysis

BACKGROUND AND OBJECTIVE

Current epidemiological studies report conflicting results for the effect of statin or metformin on pancreatic cancer overall survival. This literature review and meta-analysis summarize the studies reporting an association between statin or metformin use and overall survival of pancreatic cancer patients.

METHODS

We systematically searched for studies about the association between statin or metformin use and pancreatic cancer overall survival in electronic databases (PubMed, ISI Web of Science, MEDLINE, Cochrane, Scopus, Google Scholar). A meta-analysis based on hazard ratios (HRs) and 95% confidence intervals (CIs) was performed using random effect models. Heterogeneity between the studies was examined using I2 statistics, and sensitivity analyses were conducted to assess the robustness of the findings.

RESULTS

Of 116 statin-related articles identified, 6 retrospective cohort studies representing 12,057 patients were included. There was significant heterogeneity between studies. Statin use was associated with improved survival among pancreatic cancer patients (meta-HR = 0.75; 95% CI: 0.59, 0.90; P < 0.001). Of 311 metformin-related articles, 8 retrospective cohort studies and 2 randomized clinical trials, representing 3,042 patients were identified. Metformin use was associated with better overall survival among pancreatic cancer patients (meta-HR = 0.79; 95% CI: 0.70, 0.92, P < 0.001), and significant heterogeneity was observed between studies.

CONCLUSION

Our findings suggest that the improved survival time of pancreatic cancer patients are associated with statin or metformin use. Due to the multiple sources of heterogeneity of the original studies, these findings should be considered cautiously, and confirmed with larger prospective individual-level studies.

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.

Statins use and cancer: an update

After initial concerns regarding the association of statins with increased incidences of cancer and elevated cancer-related mortality, there are now plenty of data on the antitumor, cytostatic and cytotoxic effectiveness of this class of drugs. Here, we present a short review of possible mechanisms of antineoplastic activity obtained from preclinical research and the influence of statins on cancer treatment. In the second part of the article, we focus on the most recent data from observational clinical trials, as well as meta-analyses regarding cancer incidence and mortality in patients treated with statins.

Yes-associated protein (YAP) in pancreatic cancer: at the epicenter of a targetable signaling network associated with patient survival

Pancreatic ductal adenocarcinoma (PDAC) is generally a fatal disease with no efficacious treatment modalities. Elucidation of signaling mechanisms that will lead to the identification of novel targets for therapy and chemoprevention is urgently needed. Here, we review the role of Yes-associated protein (YAP) and WW-domain-containing Transcriptional co-Activator with a PDZ-binding motif (TAZ) in the development of PDAC. These oncogenic proteins are at the center of a signaling network that involves multiple upstream signals and downstream YAP-regulated genes. We also discuss the clinical significance of the YAP signaling network in PDAC using a recently published interactive open-access database (www.proteinatlas.org/pathology) that allows genome-wide exploration of the impact of individual proteins on survival outcomes. Multiple YAP/TEAD-regulated genes, including AJUBA, ANLN, AREG, ARHGAP29, AURKA, BUB1, CCND1, CDK6, CXCL5, EDN2, DKK1, FOSL1,FOXM1, HBEGF, IGFBP2, JAG1, NOTCH2, RHAMM, RRM2, SERP1, and ZWILCH, are associated with unfavorable survival of PDAC patients. Similarly, components of AP-1 that synergize with YAP (FOSL1), growth factors (TGFα, EPEG, and HBEGF), a specific integrin (ITGA2), heptahelical receptors (P2Y₂R, GPR87) and an inhibitor of the Hippo pathway (MUC1), all of which stimulate YAP activity, are associated with unfavorable survival of PDAC patients. By contrast, YAP inhibitory pathways (STRAD/LKB-1/AMPK, PKA/LATS, and TSC/mTORC1) indicate a favorable prognosis. These associations emphasize that the YAP signaling network correlates with poor survival of pancreatic cancer patients. We conclude that the YAP pathway is a major determinant of clinical aggressiveness in PDAC patients and a target for therapeutic and preventive strategies in this disease.

Yes-associated protein (YAP) signaling contributes to pancreatic cancer progression and is associated with poor patient survival. Previous studies have shown that YAP activates genes involved in cell proliferation to incite tumor growth and metastasis. Enrique Rozengurt and colleagues at University of California Los Angeles review the latest knowledge on YAP signaling and used the open access database The Human Protein Atlas to analyze the gene expression profile and prognosis of 176 patients with pancreatic ductal adenocarcinoma. Activation of upstream or downstream elements of the YAP signaling pathway correlated with shorter survival in patients. Conversely, the activation of signaling pathways that oppose YAP signaling were associated with a more favorable prognosis. These findings highlight YAP signaling pathway components as both prognostic markers and potential targets for developing much needed therapeutic and preventative strategies.

Simvastatin inhibits sonic hedgehog signaling and stemness features of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDA) has poor therapeutic options. Recent patient studies indicate that cholesterol-lowering statins have anti-tumor capacities. We examined several established and primary PDA and normal cell lines as well as PDA patient tissues (n = 68). We found that simvastatin inhibited viability, stemness, tumor growth and metastasis and that it enhanced the efficacy of gemcitabine. These changes were associated with modulation of Shh-related gene expression. Overexpression of Shh prevented the anti-cancer effect of simvastatin, and inhibition of Shh mimicked the simvastatin effect. In PDA tissues, expression levels of Shh, downstream mediators of Shh and progression markers, namely, cMet, CxCR4 and Vimentin, were lower when patients were prescribed statin medication prior to surgery. These results suggested that statins are cost effective and well-tolerated drugs for prevention and co-treatment of PDA.

The relationship between the use of statins and mortality, severity, and pancreatic cancer in Danish patients with chronic pancreatitis

OBJECTIVES

Chronic pancreatitis (CP) is associated with a shortened life expectancy. Statins have anti-inflammatory properties and we aimed to evaluate the association between the use of statins and the risk of death, progression of CP, and pancreatic cancer in patients with CP.

PATIENTS AND METHODS

We carried out a nested case-cohort study and included patients with CP. We used claims of proton pump inhibitors as an active comparator. Patients with cirrhosis or cancer were excluded. We evaluated the exposure on the basis of pharmacy claims of statins. We used propensity score matching with a statins : nonstatins ratio of 1 : 1.

RESULTS

A total of 4807 patients were eligible for propensity score matching; 33% were women and the mean (SD) age at cohort entry was 56 (10) years. During follow-up, a total of 2073 (43%) patients had died and the risk of death was significantly lower among patients using statins versus no statins among 678 matched patients [hazard ratio (HR) 0.64; 95% confidence interval (CI): 0.49-0.83]. Use of statins versus no statins was associated with decreased progression of CP, with an HR of 0.21 (95% CI: 0.17-0.26). Pancreatic cancer occurred in 117 (2.4%) patients and we found a lower risk of pancreatic cancer in statin-treated patients compared with no statins, with a HR of 0.21 (95% CI: 0.06-0.70).

CONCLUSION

In this nationwide study, we found lower risks of mortality, disease progression, and pancreatic cancer in patients with CP using statins. The study is limited by its retrospective design, but supports the hypothesis that statins may affect the course of CP.

Pancreatic Adenocarcinoma Therapeutic Targets Revealed by Tumor-Stroma Cross-Talk Analyses in Patient-Derived Xenografts

Preclinical models based on patient-derived xenografts have remarkable specificity in distinguishing transformed human tumor cells from non-transformed murine stromal cells computationally. We obtained 29 pancreatic ductal adenocarcinoma (PDAC) xenografts from either resectable or non-resectable patients (surgery and endoscopic ultrasound-guided fine-needle aspirate, respectively). Extensive multiomic profiling revealed two subtypes with distinct clinical outcomes. These subtypes uncovered specific alterations in DNA methylation and transcription as well as in signaling pathways involved in tumor-stromal cross-talk. The analysis of these pathways indicates therapeutic opportunities for targeting both compartments and their interactions. In particular, we show that inhibiting NPC1L1 with Ezetimibe, a clinically available drug, might be an efficient approach for treating pancreatic cancers. These findings uncover the complex and diverse interplay between PDAC tumors and the stroma and demonstrate the pivotal role of xenografts for drug discovery and relevance to PDAC.

KRAS, YAP, and obesity in pancreatic cancer: A signaling network with multiple loops

Pancreatic ductal adenocarcinoma (PDAC) continues to be a lethal disease with no efficacious treatment modalities. The incidence of PDAC is expected to increase, at least partially because of the obesity epidemic. Increased efforts to prevent or intercept this disease are clearly needed. Mutations in KRAS are initiating events in pancreatic carcinogenesis supported by genetically engineered mouse models of the disease. However, oncogenic KRAS is not entirely sufficient for the development of fully invasive PDAC. Additional genetic mutations and/or environmental, nutritional, and metabolic stressors, e.g. inflammation and obesity, are required for efficient PDAC formation with activation of KRAS downstream effectors. Multiple factors "upstream" of KRAS associated with obesity, including insulin resistance, inflammation, changes in gut microbiota and GI peptides, can enhance/modulate downstream signals. Multiple signaling networks and feedback loops "downstream" of KRAS have been described that respond to obesogenic diets. We propose that KRAS mutations potentiate a signaling network that is promoted by environmental factors. Specifically, we envisage that KRAS mutations increase the intensity and duration of the growth-promoting signaling network. As the transcriptional activator YAP plays a critical role in the network, we conclude that the rationale for targeting the network (at different points), e.g. with FDA approved drugs such as statins and metformin, is therefore compelling.

Exclusive and Combined Use of Statins and Aspirin and the Risk of Pancreatic Cancer: a Case-Control Study

Data on the association between aspirin and statin use and Pancreatic Ductal AdenoCarcinoma (PDAC) risk are conflicting. These drugs are often co-prescribed, but no studies evaluated the potential combined or confounding effect of the two at the same time. We aimed to investigate the association between aspirin and statin exclusive and combined use and PDAC occurrence. Data on environmental factors, family and medical history were screened in a case-control study. PDAC cases were matched to controls for age and gender. Power calculation performed ahead. Odds ratios (OR) and 95% confidence intervals(CI) were obtained from multivariable logistic regression analysis. In 408 PDAC patients and 816 matched controls, overall statin (OR 0.61; 95%CI,0.43-0.88), but not aspirin use was associated to reduced PDAC risk. Compared to non-users, exclusive statin (OR 0.51; 95%CI,0.32-0.80) and exclusive aspirin users (OR 0.64; 95%CI,0.40-1.01) had reduced PDAC risk. Concomitant statin and aspirin use did not further reduce the risk compared with statin use alone and no interaction was evident. Statin protective association was dose-dependent, and consistent in most subgroups, being stronger in smokers, elderly, obese and non-diabetic patients. The present study suggests that statin use is associated to reduced PDAC risk, supporting a chemopreventive action of statins on PDAC.

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.

Influence of Statins and Cholesterol on Mortality Among Patients With Pancreatic Cancer

Background

Recent studies have suggested associations between statins and enhanced survival among patients with pancreatic ductal adenocarcinoma (PDAC). However, the relationship between statins, cholesterol, and survival remains unclear.

Methods

We conducted a retrospective cohort study on 2142 PDAC patients in a regional integrated healthcare system from 2006 to 2014. Electronic pharmacy records were used to abstract information on the type, length, and dosage of statin exposures starting in the year prior to diagnosis. The cumulative and individual effects of simvastatin, lovastatin, atorvastatin, pravastatin, and rosuvastatin on mortality were assessed using Cox proportional hazards regression. Statins were evaluated as any use (pre- and postdiagnosis as a time-dependent variable) and baseline use (prediagnosis only). We also evaluated whether low-density lipoprotein (LDL) cholesterol, measured at various time windows prior to diagnosis, had an independent influence on survival. Additional analyses were performed to examine whether cholesterol mediated the relationship between statins and mortality. All models included age, race, stage, surgery, gemcitabine-based chemotherapy, and the Charlson comorbidity index as covariates.

Results

Any (hazard ratio [HR] = 0.87, 95% confidence interval [CI] = 0.79 to 0.97) and baseline (HR = 0.88, 95% CI = 0.79 to 0.98) statin use were both associated with a decreased risk in mortality. When assessing individual statins, we found reduced mortality among simvastatin (HR = 0.87, 95% CI = 0.77 to 0.98) and atorvastatin (HR = 0.58, 95% CI = 0.46 to 0.72) users. Cholesterol was not associated with mortality and did not mediate any relationships between statins and survival.

Conclusions

Statin use rather than cholesterol level was associated with lower mortality risk in patients with pancreatic cancer. Statins appear to improve survival through a lipid-independent mechanism.

High expression of GFAT1 predicts poor prognosis in patients with pancreatic cancer

Pancreatic cancer is one of the most lethal of all types of cancer, with the 5-year survival rate ranging only at 6–7%. The aberrant glucose metabolism is one of the hallmarks of cancer cells, and as a branch of glucose metabolism, hexosamine biosynthesis pathway (HBP) has been reported to play a critical role in the insulin resistance and progression of cancer. Glutamine:fructose-6-phosphate amidotransferase (GFAT1) is the rate-limiting enzyme of the HBP; nevertheless, the prognostic value of GFAT1 in pancreatic cancer remains elusive. In this study, we found that the expression of GFAT1 was increased in pancreatic cancer samples compared to peri-tumor tissues. High expression of GFAT1 was positively associated with lymph node metastasis, pTNM stage and shorter overall survival (OS) in pancreatic cancer patients. GFAT1 was identified as an independent prognosticator for OS, and combining GFAT1 expression with pTNM stage generated a predictive nomogram, which showed better prognostic efficiency for OS in patients with pancreatic cancer. In summary, high GFAT1 expression is identified as an independent predictor of adverse clinical outcome in our small number of pancreatic cancer patients, and the practical prognostic nomogram model may help clinicians in decision making and the design of clinical studies.

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.

Statin Use and Its Impact on Survival in Pancreatic Cancer Patients

Statins are cholesterol-lowering medications that are associated with a number of signaling pathways involved in carcinogenesis. Recent observational studies raised the possibility that the use of statins may reduce overall mortality in various types of cancer. We investigated whether statins used after pancreatic cancer diagnosis are associated with longer survival in pancreatic cancer patients.We retrospectively analyzed data from 1761 patients newly diagnosed with pancreatic adenocarcinoma between January 1, 2006, and December 31, 2014. We used the time-dependent Cox proportional hazards regression model to estimate mortality among pancreatic cancer patients according to statin use.Among the 1761 pancreatic cancer patients, 118 patients had used statins. During the study period, 1176 patients (66.7%) died. After adjusting for age, sex, location of cancer, cancer stage, diabetes mellitus, hypertension, dyslipidemia, smoking, alcohol use, body mass index, and CA 19-9, statin use was associated with a lower risk of cancer death (hazard ratio [HR], 0.780; 95% confidence interval [CI], 0.617-0.986), especially among simvastatin users (HR, 0.554; 95% CI, 0.312-0.982) and atorvastatin users (HR, 0.636; 95% CI, 0.437-0.927). Subgroup analysis showed that overall survival was statistically significantly longer in patients with nonmetastatic pancreatic cancer (log-rank P = 0.024).We found that the use of simvastatin and atorvastatin after cancer diagnosis is associated with longer survival in patients with nonmetastatic pancreatic adenocarcinoma.