Low dosage combination treatment with metformin and simvastatin inhibits obesity-promoted pancreatic cancer development in male KrasG12D mice.

Pancreatic ductal adenocarcinoma (PDAC), a highly lethal disease with limited therapeutic options, may benefit from repurposing of FDA-approved drugs in preventive or interceptive strategies in high-risk populations. Previous animal studies demonstrated that the use of metformin and statins as single agents at relatively high doses restrained PDAC development. Here, four-week-old mice expressing KrasG12D in all pancreatic lineages (KC mice) and fed an obesogenic high fat, high calorie diet that promotes early PDAC development were randomized onto low dosage metformin, simvastatin, or both drugs in combination administered orally. Dual treatment attenuated weight gain, fibro-inflammation, and development of advanced PDAC precursor lesions (pancreatic intraepithelial neoplasia [PanIN]-3) in male KC mice, without significant effect in females or when administered individually. Dual-treated KC mice had reduced proliferation of PanIN cells and decreased transcriptional activity of the Hippo effectors, YAP and TAZ, which are important regulators of PDAC development. Metformin and simvastatin also synergistically inhibited colony formation of pancreatic cancer cells in vitro. Together, our data demonstrated that a combination of low doses of metformin and simvastatin inhibits PDAC development and imply that both drugs are promising agents for being tested in clinical trials for preventing pancreatic cancer progression.

[Prevention of pancreatic cancer]. / Prävention des Pankreaskarzinoms.

The incidence of pancreatic cancer is rising in Germany. At present pancreatic cancer is the third commonest cause of cancer death but is expected to become the second in 2030 and finally the leading cause of cancer death in 2050. Pancreatic ductal adenocarcinoma (PC) is generally diagnosed at far advanced stages and 5-year-survival has remained poor. Modifiable risk factors of PC are tobacco smoking, excess body weight, alcohol use, type 2-diabetes and the metabolic syndrome. Smoking cessation and -in case of obesity- intentional weight loss can reduce PC risk by as much as 50 %. Early detection of asymptomatic sporadic PC at stage IA - stage IA-PC now has a 5-year-survival rate of about 80 %- has become a realistic chance for people older than 50 years with new-onset diabetes.

Genetic testing to guide screening for pancreatic ductal adenocarcinoma: Results of a microsimulation model.

BACKGROUND: First-degree relatives (FDRs) of patients with pancreatic ductal adenocarcinoma (PDAC) have elevated PDAC risk, partially due to germline genetic variants. We evaluated the potential effectiveness of genetic testing to target MRI-based screening among FDRs. METHODS: We used a microsimulation model of PDAC, calibrated to Surveillance, Epidemiology, and End Results (SEER) data, to estimate the potential life expectancy (LE) gain of screening for each of the following groups of FDRs: individuals who test positive for each of eight variants associated with elevated PDAC risk (e.g., BRCA2, CDKN2A); individuals who test negative; and individuals who do not test. Screening was assumed to take place if LE gains were achievable. We simulated multiple screening approaches, defined by starting age and frequency. Sensitivity analysis evaluated changes in results given varying model assumptions. RESULTS: For women, 92% of mutation carriers had projected LE gains from screening for PDAC, if screening strategies (start age, frequency) were optimized. Among carriers, LE gains ranged from 0.1 days (ATM+ women screened once at age 70) to 510 days (STK11+ women screened annually from age 40). For men, LE gains were projected for all mutation carriers, ranging from 0.2 days (BRCA1+ men screened once at age 70) to 620 days (STK11+ men screened annually from age 40). For men and women who did not undergo genetic testing, or for whom testing showed no variant, screening yielded small LE benefit (0-2.1 days). CONCLUSIONS: Genetic testing of FDRs can inform targeted PDAC screening by identifying which FDRs may benefit.

A review of physical activity in pancreatic ductal adenocarcinoma: Epidemiology, intervention, animal models, and clinical trials.

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest types of cancer, and the increasing incidence of PDAC may be related to the prevalence of obesity. Physical activity (PA), a method known to mitigate obesity by increasing total energy expenditure, also modifies multiple cellular pathways associated with cancer hallmarks. Epidemiologic evidence has shown that PA can lower the risk of developing a variety of cancers, reduce some of the detrimental side effects of treatments, and improve patient's quality of life during cancer treatment. However, little is known about the pathways underlying the correlations observed between PA interventions and PDAC. Moreover, there is no standard dose of PA intervention that is ideal for PDAC prevention or as an adjuvant of cancer treatments. In this review, we summarize relevant literature showing how PDAC patients can benefit from PA, the potential of PA as an adjuvant treatment for PDAC, the studies using preclinical models of PDAC to study PA, and the clinical trials to date assessing the effects of PA in PDAC.

Inflammatory cytokine-regulated tRNA-derived fragment tRF-21 suppresses pancreatic ductal adenocarcinoma progression.

The tumorigenic mechanism for pancreatic ductal adenocarcinoma (PDAC) is not clear, although chronic inflammation is implicated. Here, we identified an inflammatory cytokine-regulated transfer RNA-derived (tRNA-derived) fragment, tRF-21-VBY9PYKHD (tRF-21), as a tumor suppressor in PDAC progression. We found that the biogenesis of tRF-21 could be inhibited by leukemia inhibitory factor and IL-6 via the splicing factor SRSF5. Reduced tRF-21 promoted AKT2/1-mediated heterogeneous nuclear ribonucleoprotein L (hnRNP L) phosphorylation, enhancing hnRNP L to interact with dead-box helicase 17 (DDX17) to form an alternative splicing complex. The provoked hnRNP L-DDX17 activity preferentially spliced Caspase 9 and mH2A1 pre-mRNAs to form Caspase 9b and mH2A1.2, promoting PDAC cell malignant phenotypes. The tRF-21 levels were significantly lower in PDACs than in normal tissues, and patients with low tRF-21 levels had a poor prognosis. Treatment of mouse PDAC xenografts or patient-derived xenografts (PDXs) with tRF-21 mimics repressed tumor growth and metastasis. These results demonstrate that tRF-21 has a tumor-suppressive effect and is a potential therapeutic agent for PDAC.

PRMT1-dependent regulation of RNA metabolism and DNA damage response sustains pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer that has remained clinically challenging to manage. Here we employ an RNAi-based in vivo functional genomics platform to determine epigenetic vulnerabilities across a panel of patient-derived PDAC models. Through this, we identify protein arginine methyltransferase 1 (PRMT1) as a critical dependency required for PDAC maintenance. Genetic and pharmacological studies validate the role of PRMT1 in maintaining PDAC growth. Mechanistically, using proteomic and transcriptomic analyses, we demonstrate that global inhibition of asymmetric arginine methylation impairs RNA metabolism, which includes RNA splicing, alternative polyadenylation, and transcription termination. This triggers a robust downregulation of multiple pathways involved in the DNA damage response, thereby promoting genomic instability and inhibiting tumor growth. Taken together, our data support PRMT1 as a compelling target in PDAC and informs a mechanism-based translational strategy for future therapeutic development.Statement of significancePDAC is a highly lethal cancer with limited therapeutic options. This study identified and characterized PRMT1-dependent regulation of RNA metabolism and coordination of key cellular processes required for PDAC tumor growth, defining a mechanism-based translational hypothesis for PRMT1 inhibitors.

Cancer-Associated Fibroblasts in Pancreatic Ductal Adenocarcinoma Determine Response to SLC7A11 Inhibition.

Cancer-associated fibroblasts (CAF) are major contributors to pancreatic ductal adenocarcinoma (PDAC) progression through protumor signaling and the generation of fibrosis, the latter of which creates a physical barrier to drugs. CAF inhibition is thus an ideal component of any therapeutic approach for PDAC. SLC7A11 is a cystine transporter that has been identified as a potential therapeutic target in PDAC cells. However, no prior study has evaluated the role of SLC7A11 in PDAC tumor stroma and its prognostic significance. Here we show that high expression of SLC7A11 in human PDAC tumor stroma, but not tumor cells, is independently prognostic of poorer overall survival. Orthogonal approaches showed that PDAC-derived CAFs are highly dependent on SLC7A11 for cystine uptake and glutathione synthesis and that SLC7A11 inhibition significantly decreases CAF proliferation, reduces their resistance to oxidative stress, and inhibits their ability to remodel collagen and support PDAC cell growth. Importantly, specific ablation of SLC7A11 from the tumor compartment of transgenic mouse PDAC tumors did not affect tumor growth, suggesting the stroma can substantially influence PDAC tumor response to SLC7A11 inhibition. In a mouse orthotopic PDAC model utilizing human PDAC cells and CAFs, stable knockdown of SLC7A11 was required in both cell types to reduce tumor growth, metastatic spread, and intratumoral fibrosis, demonstrating the importance of targeting SLC7A11 in both compartments. Finally, treatment with a nanoparticle gene-silencing drug against SLC7A11, developed by our laboratory, reduced PDAC tumor growth, incidence of metastases, CAF activation, and fibrosis in orthotopic PDAC tumors. Overall, these findings identify an important role of SLC7A11 in PDAC-derived CAFs in supporting tumor growth. SIGNIFICANCE: This study demonstrates that SLC7A11 in PDAC stromal cells is important for the tumor-promoting activity of CAFs and validates a clinically translatable nanomedicine for therapeutic SLC7A11 inhibition in PDAC.

Mesothelin blockage by Amatuximab suppresses cell invasiveness, enhances gemcitabine sensitivity and regulates cancer cell stemness in mesothelin-positive pancreatic cancer cells.

BACKGROUND: Mesothelin is a 40-kDa glycoprotein that is highly overexpressed in various types of cancers, however molecular mechanism of mesothelin has not been well-known. Amatuximab is a chimeric monoclonal IgG1/k antibody targeting mesothelin. We recently demonstrated that the combine therapy of Amatuximab and gemcitabine was effective for peritonitis of pancreatic cancer in mouse model. METHODS: We discover the role and potential mechanism of mesothelin blockage by Amatuximab in human pancreatic cells both expressing high or low level of mesothelin in vitro experiment and peritonitis mouse model of pancreatic cancer. RESULTS: Mesothelin blockage by Amatuximab lead to suppression of invasiveness and migration capacity in AsPC-1 and Capan-2 (high mesothelin expression) and reduce levels of pMET expression. The combination of Amatuximab and gemcitabine suppressed proliferation of AsPC-1 and Capan-2 more strongly than gemcitabine alone. These phenomena were not observed in Panc-1 and MIA Paca-2 (Mesothelin low expression). We previously demonstrated that Amatuximab reduced the peritoneal mass in mouse AsPC-1 peritonitis model and induced sherbet-like cancer cell aggregates, which were vanished by gemcitabine. In this study, we showed that the cancer stem cell related molecule such as ALDH1, CD44, c-MET, as well as proliferation related molecules, were suppressed in sherbet-like aggregates, but once sherbet-like aggregates attached to peritoneum, they expressed these molecules strongly without the morphological changes. CONCLUSIONS: Our work suggested that Amatuximab inhibits the adhesion of cancer cells to peritoneum and suppresses the stemness and viability of those, that lead to enhance the sensitivity for gemcitabine.

FGF21 in obesity and cancer: New insights.

The endocrine FGF21 was discovered as a novel metabolic regulator in 2005 with new functions bifurcating from the canonic heparin-binding FGFs that directly promote cell proliferation and growth independent of a co-receptor. Early studies have demonstrated that FGF21 is a stress sensor in the liver and possibly, several other endocrine and metabolic tissues. Hepatic FGF21 signals via endocrine routes to quench episodes of metabolic derangements, promoting metabolic homeostasis. The convergence of mouse and human studies shows that FGF21 promotes lipid catabolism, including lipolysis, fatty acid oxidation, mitochondrial oxidative activity, and thermogenic energy dissipation, rather than directly regulating insulin and appetite. The white and brown adipose tissues and, to some extent, the hypothalamus, all of which host a transmembrane receptor binary complex of FGFR1 and co-receptor KLB, are considered the essential tissue and molecular targets of hepatic or pharmacological FGF21. On the other hand, a growing body of work has revealed that pancreatic acinar cells form a constitutive high-production site for FGF21, which then acts in an autocrine or paracrine mode. Beyond regulation of macronutrient metabolism and physiological energy expenditure, FGF21 appears to function in forestalling the development of fatty pancreas, steato-pancreatitis, fatty liver, and steato-hepatitis, thereby preventing the development of advanced pathologies such as pancreatic ductal adenocarcinoma or hepatocellular carcinoma. This review is intended to provide updates on these new discoveries that illuminate the protective roles of FGF21-FGFR1-KLB signal pathway in metabolic anomalies-associated severe tissue damage and malignancy, and to inform potential new preventive or therapeutic strategies for obesity-inflicted cancer patients via reducing metabolic risks and inflammation.

CAR T cells targeting tumor endothelial marker CLEC14A inhibit tumor growth.

Engineering T cells to express chimeric antigen receptors (CARs) specific for antigens on hematological cancers has yielded remarkable clinical responses, but with solid tumors, benefit has been more limited. This may reflect lack of suitable target antigens, immune evasion mechanisms in malignant cells, and/or lack of T cell infiltration into tumors. An alternative approach, to circumvent these problems, is targeting the tumor vasculature rather than the malignant cells directly. CLEC14A is a glycoprotein selectively overexpressed on the vasculature of many solid human cancers and is, therefore, of considerable interest as a target antigen. Here, we generated CARs from 2 CLEC14A-specific antibodies and expressed them in T cells. In vitro studies demonstrated that, when exposed to their target antigen, these engineered T cells proliferate, release IFN-γ, and mediate cytotoxicity. Infusing CAR engineered T cells into healthy mice showed no signs of toxicity, yet these T cells targeted tumor tissue and significantly inhibited tumor growth in 3 mouse models of cancer (Rip-Tag2, mPDAC, and Lewis lung carcinoma). Reduced tumor burden also correlated with significant loss of CLEC14A expression and reduced vascular density within malignant tissues. These data suggest the tumor vasculature can be safely and effectively targeted with CLEC14A-specific CAR T cells, offering a potent and widely applicable therapy for cancer.

Italian registry of families at risk of pancreatic cancer: AISP Familial Pancreatic Cancer Study Group.

Pancreatic cancer is one of the main causes of cancer-related death worldwide, with a survival rate around 9%. In Italy 13,500 new cases of pancreatic cancer occurred in 2019. It is estimated that at least 5% have a hereditary background. Surveillance is advisable for healthy individuals with specific genetic syndromes with or without family history of pancreatic cancer or members of families with multiple cases of pancreatic cancer, irrespective of genetic syndromes. In 2010 the Italian Association for the Study of the Pancreas (AISP) defined criteria to include individuals in such surveillance programs with the first-round results published in 2019. In order to include other categories at high-risk and increase the diagnostic yield of surveillance, these criteria have recently been modified. The present position paper presents the updated criteria of the Italian Registry of Families at Risk of Pancreatic Cancer (IRFARPC) with their diagnostic yield calculation. Also, AISP priority projects concerning: (a) increasing awareness of citizens and primary care physicians through a dedicated App; (b) increasing access to germline testing to personalize surveillance; (c) measuring psychological impact of surveillance; (d) investigating the role of risk-modifiers and (e) evaluating the cost-effectiveness and ability to save lives of the program are briefly presented.

Tuft Cells Inhibit Pancreatic Tumorigenesis in Mice by Producing Prostaglandin D2.

BACKGROUND & AIMS: Development of pancreatic ductal adenocarcinoma (PDA) involves acinar to ductal metaplasia and genesis of tuft cells. It has been a challenge to study these rare cells because of the lack of animal models. We investigated the role of tuft cells in pancreatic tumorigenesis. METHODS: We performed studies with LSL-KrasG12D/+;Ptf1aCre/+ mice (KC; develop pancreatic tumors), KC mice crossed with mice with pancreatic disruption of Pou2f3 (KPouC mice; do not develop tuft cells), or mice with pancreatic disruption of the hematopoietic prostaglandin D synthase gene (Hpgds, KHC mice) and wild-type mice. Mice were allowed to age or were given caerulein to induce pancreatitis; pancreata were collected and analyzed by histology, immunohistochemistry, RNA sequencing, ultrastructural microscopy, and metabolic profiling. We performed laser-capture dissection and RNA-sequencing analysis of pancreatic tissues from 26 patients with pancreatic intraepithelial neoplasia (PanIN), 19 patients with intraductal papillary mucinous neoplasms (IPMNs), and 197 patients with PDA. RESULTS: Pancreata from KC mice had increased formation of tuft cells and higher levels of prostaglandin D2 than wild-type mice. Pancreas-specific deletion of POU2F3 in KC mice (KPouC mice) resulted in a loss of tuft cells and accelerated tumorigenesis. KPouC mice had increased fibrosis and activation of immune cells after administration of caerulein. Pancreata from KPouC and KHC mice had significantly lower levels of prostaglandin D2, compared with KC mice, and significantly increased numbers of PanINs and PDAs. KPouC and KHC mice had increased pancreatic injury after administration of caerulein, significantly less normal tissue, more extracellular matrix deposition, and higher PanIN grade than KC mice. Human PanIN and intraductal papillary mucinous neoplasm had gene expression signatures associated with tuft cells and increased expression of Hpgds messenger RNA compared with PDA. CONCLUSIONS: In mice with KRAS-induced pancreatic tumorigenesis, loss of tuft cells accelerates tumorigenesis and increases the severity of caerulein-induced pancreatic injury, via decreased production of prostaglandin D2. These data are consistent with the hypothesis that tuft cells are a metaplasia-induced tumor attenuating cell type.

Prophylactic total pancreatectomy in individuals at high risk of pancreatic ductal adenocarcinoma (PROPAN): systematic review and shared decision-making programme using decision tables.

BACKGROUND: Individuals with a very high lifetime risk of developing pancreatic ductal adenocarcinoma; for example, hereditary pancreatitis and main-duct or mixed-type intraductal papillary mucinous neoplasm, may wish to discuss prophylactic total pancreatectomy but strategies to do so are lacking. OBJECTIVE: To develop a shared decision-making programme for prophylactic total pancreatectomy using decision tables. METHODS: Focus group meetings with patients were used to identify relevant questions. Systematic reviews were performed to answer these questions. RESULTS: The first tables included hereditary pancreatitis and main-duct or mixed-type intraductal papillary mucinous neoplasm. No studies focused on prophylactic total pancreatectomy in these groups. In 52 studies (3570 patients), major morbidity after total pancreatectomy was 25% and 30-day mortality was 6%. After minimally invasive total pancreatectomy (seven studies, 35 patients) this was, respectively, 13% and 0%. Exocrine insufficiency-related symptoms occurred in 33%. Quality of life after total pancreatectomy was slightly lower compared with the general population. CONCLUSION: The decision tables can be helpful for discussing prophylactic total pancreatectomy with individuals at high risk of pancreatic ductal adenocarcinoma.

p38γ MAPK Is Essential for Aerobic Glycolysis and Pancreatic Tumorigenesis.

KRAS is mutated in most pancreatic ductal adenocarcinomas (PDAC) and yet remains undruggable. Here, we report that p38γ MAPK, which promotes PDAC tumorigenesis by linking KRAS signaling and aerobic glycolysis (also called the Warburg effect), is a novel therapeutic target. p38γ interacted with a glycolytic activator PFKFB3 that was dependent on mutated KRAS. KRAS transformation and overexpression of p38γ increased expression of PFKFB3 and glucose transporter GLUT2, conversely, silencing mutant KRAS, and p38γ decreased PFKFB3 and GLUT2 expression. p38γ phosphorylated PFKFB3 at S467, stabilized PFKFB3, and promoted their interaction with GLUT2. Pancreatic knockout of p38γ decreased p-PFKFB3/PFKFB3/GLUT2 protein levels, reduced aerobic glycolysis, and inhibited PDAC tumorigenesis in KPC mice. PFKFB3 and GLUT2 depended on p38γ to stimulate glycolysis and PDAC growth and p38γ required PFKFB3/S467 to promote these activities. A p38γ inhibitor cooperated with a PFKFB3 inhibitor to blunt aerobic glycolysis and PDAC growth, which was dependent on p38γ. Moreover, overexpression of p38γ, p-PFKFB3, PFKFB3, and GLUT2 in PDAC predicted poor clinical prognosis. These results indicate that p38γ links KRAS oncogene signaling and aerobic glycolysis to promote pancreatic tumorigenesis through PFKFB3 and GLUT2, and that p38γ and PFKFB3 may be targeted for therapeutic intervention in PDAC. SIGNIFICANCE: These findings show that p38γ links KRAS oncogene signaling and the Warburg effect through PFKBF3 and Glut2 to promote pancreatic tumorigenesis, which can be disrupted via inhibition of p38γ and PFKFB3.

Resveratrol slows the tumourigenesis of pancreatic cancer by inhibiting NFκB activation.

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant tumour with an extremely poor prognosis due to its insidious initiation and a lack of therapeutic strategies. Resveratrol suppresses pancreatic cancer progression and attenuates pancreatitis by modulating multiple targets, including nuclear factor kappa B (NFκB) signalling pathways. However, the effect of resveratrol on pancreatic cancer initiation and its mechanisms remain unclear. In this study, we utilised the LSL-KrasG12D/+; Pdx1-Cre (KC) spontaneous pancreatic precancerous lesion mouse model to explore the anti-tumourigenesis mechanisms of resveratrol in vivo. In vitro acinar-to-ductal metaplasia (ADM) and pancreatic intraepithelial neoplasias (PanINs) formation assays were performed by pancreatic acinar cell 3-dimensional (3D) culture. Histopathological analysis was used to examine the pathological morphology of pancreatic tissues. Resveratrol prevented the progression of pancreatic precancerous lesions and inhibited the activation of NFκB signalling pathway-related molecules in KC mouse pancreatic tissues. In addition, resveratrol reduced the severity of cerulein-induced pancreatitis and the formation of ADM/PanINs in vivo and in vitro, which may be related to its effect on NFκB inactivation. Furthermore, pancreatic acinar 3D culture demonstrated that activation of the NFκB signalling pathway promoted the formation of ADM/PanINs in vitro, and this initiating effect of NFκB was blocked by resveratrol. Resveratrol slowed the tumourigenesis of pancreatic cancer by inhibiting NFκB activation.

DCLK1-Isoform2 Alternative Splice Variant Promotes Pancreatic Tumor Immunosuppressive M2-Macrophage Polarization.

Tumor-associated M2-macrophages are one of the most abundant immunosuppressive cell types in the pancreatic ductal adenocarcinoma (PDAC) tumor microenvironment (TME). However, the molecular mechanisms responsible for the generation of M2-macrophages are unclear. Here, we demonstrated that overexpression of DCLK1-isoform2 in AsPC1 and MIA PaCa2 cells resulted in the polarization of M1-macrophages toward an M2 phenotype via secreted chemokines/cytokines. These M2-macrophages enhanced parental PDAC cell migration, invasion, and self-renewal, and this was associated with increased expression of Snail and Slug. We observed distinct expression of Dclk-isoform2, marked infiltration of M2-macrophages, and a marginal increase of CD8+ T cells in 20-week-old KPCY mice pancreas compared with 5 weeks old. Utilizing an autochthonous mouse model of pancreatic adenocarcinoma, we observed distinct immunoreactive Dclk1 and arginase1 in tissues where CD8+ T-cell infiltration was low and observed a paucity of DCLK1 and arginase1 staining where CD8+ T-cell infiltration was high. Finally, we found that DCLK1-isoform2 tumor-educated M2-macrophages inhibit CD8+ T-cell proliferation and granzyme-B activation. Inhibition of DCLK1 in an organoid coculture system enhanced CD8+ T-cell activation and associated organoid death. We conclude that DCLK1-isoform2 is a novel initiator of alternate macrophage activation that contributes to the immunosuppression observed in the PDAC TME. These data suggest that tumor DCLK1-isoform2 may be an attractive target for PDAC therapy, either alone or in conjunction with immunotherapeutic strategies.

Intraductal Tubulopapillary Neoplasm of the Pancreas and Bile Duct: A Review.

Intraductal tubulopapillary neoplasms (ITPNs) of the pancreas and bile duct are contemporary entities. It is unclear on how to best manage patients with this diagnosis because little is known about its progression to cancer. This review provides an update on the current knowledge of ITPN of the pancreas and bile duct with an overview of clinical, radiological, histopathological, and molecular features, as well as the prognosis and management. Embase and Medline databases search were performed to identify studies that evaluated ITPN of the pancreas and bile duct. The infrequent exposure to this variant poses a diagnostic challenge. The diagnosis of ITPN is almost always made postoperatively because there are no characteristics on radiological studies to distinguish it from other cystic neoplasms of the pancreas. As ITPN has a favorable prognosis, it is crucial to establish an accurate diagnosis and differentiate it from other pancreatic and biliary variants. These neoplasms are considered to be precursor lesions to carcinomas, hence, surgery and close clinical surveillance are recommended. Further studies are essential to elucidate the natural history of ITPN, guide best treatment strategy and determine disease recurrence and survival.

Risk Factors for Pancreatic Cancer and the Necessity of Long-Term Surveillance in Patients With Pancreatic Cystic Lesions.

OBJECTIVES: Pancreatic cystic lesions (PCLs) are a risk factor for pancreatic cancer (PC). Which PCLs should be surveilled and necessity of long-term observation are still controversial. METHODS: From January 2000 to March 2016, we enrolled 1137 patients with PCLs observed for 1 year. We defined PCLs with cyst size of greater than 30 mm, main pancreatic duct (MPD) of greater than 5 mm or mural nodule as high-risk group, and others as low-risk group (LRG). Kaplan-Meier method and Cox proportional hazard model were applied to assess incidence and risk factors of PC. RESULTS: In 107 high-risk group and 1030 LRG patients, mean observation period was 4.3 years and 5.0 years, respectively, and 5-year PC incidence was 12.0% and 2.8%, respectively. In LRG, MPD of greater than 3 mm, diabetes mellitus, and presumed branch-duct intraductal papillary mucinous neoplasia (BD-IPMN), defined as PCLs fulfilling any of multilocular formation, multiplicity, or MPD communication, were independent risk factors for PC. In 450 LRG observed for 5 years, 10-year PC incidence was higher in PCLs with our identified risk factors. There was no PC occurrence in PCLs not presumed BD-IPMN after 5-year observation. CONCLUSIONS: Continuous surveillance is needed after 5-year observation, especially in LRG with our identified risk factors. For discontinuing surveillance, PCLs not presumed BD-IPMN at fifth year could be candidates.

m6A demethylase ALKBH5 inhibits pancreatic cancer tumorigenesis by decreasing WIF-1 RNA methylation and mediating Wnt signaling.

BACKGROUND: Pancreatic cancer is one of the most lethal types of cancer with extremely poor diagnosis and prognosis, and chemo-resistance remains a major challenge. The dynamic and reversible N6-methyladenosine (m6A) RNA modification has emerged as a new layer of epigenetic gene regulation. METHODS: qRT-PCR and IHC were applied to examine ALKBH5 levels in normal and pancreatic cancer tissues. Cancer cell proliferation and chemo-resistance were evaluated by clonogenic formation, chemosensitivity detection, and Western blotting assays. m6A-seq was performed to identify target genes. We evaluated the inhibitory effect of ALKBH5 in both in vivo and in vitro models. RESULTS: Here, we show that m6A demethylase ALKBH5 is downregulated in gemcitabine-treated patient-derived xenograft (PDX) model and its overexpression sensitized pancreatic ductal adenocarcinoma (PDAC) cells to chemotherapy. Decreased ALKBH5 levels predicts poor clinical outcome in PDAC and multiple other cancers. Furthermore, silencing ALKBH5 remarkably increases PDAC cell proliferation, migration, and invasion both in vitro and in vivo, whereas its overexpression causes the opposite effects. Global m6A profile revealed altered expression of certain ALKBH5 target genes, including Wnt inhibitory factor 1 (WIF-1), which is correlated with WIF-1 transactivation and mediation of the Wnt pathway. CONCLUSIONS: Our work uncovers the tumor suppressive and chemo-sensitizing function for ALKBH5, which provides insight into critical roles of m6A methylation in PDAC.

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.