Challenges of Pancreatic Cancer. Cancer J. 2015;21:188-193. [PMID: 26049698 DOI: 10.1097/ppo.0000000000000109]

The roles of lncRNAs and miRNAs in pancreatic cancer: a focus on cancer development and progression and their roles as potential biomarkers

Pancreatic ductal adenocarcinoma (PDAC) is among the most penetrative malignancies affecting humans, with mounting incidence prevalence worldwide. This cancer is usually not diagnosed in the early stages. There is also no effective therapy against PDAC, and most patients have chemo-resistance. The combination of these factors causes PDAC to have a poor prognosis, and often patients do not live longer than six months. Because of the failure of conventional therapies, the identification of key biomarkers is crucial in the early diagnosis, treatment, and prognosis of pancreatic cancer. 65% of the human genome encodes ncRNAs. There are different types of ncRNAs that are classified based on their sequence lengths and functions. They play a vital role in replication, transcription, translation, and epigenetic regulation. They also participate in some cellular processes, such as proliferation, differentiation, metabolism, and apoptosis. The roles of ncRNAs as tumor suppressors or oncogenes in the growth of tumors in a variety of tissues, including the pancreas, have been demonstrated in several studies. This study discusses the key roles of some lncRNAs and miRNAs in the growth and advancement of pancreatic carcinoma. Because they are involved not only in the premature identification, chemo-resistance and prognostication, also their roles as potential biomarkers for better management of PDAC patients.

Drug Delivery Strategies for the Treatment of Pancreatic Cancer

Pancreatic cancer is fast becoming a global menace and it is projected to be the second leading cause of cancer-related death by 2030. Pancreatic adenocarcinomas, which develop in the pancreas' exocrine region, are the predominant type of pancreatic cancer, representing about 95% of total pancreatic tumors. The malignancy progresses asymptomatically, making early diagnosis difficult. It is characterized by excessive production of fibrotic stroma known as desmoplasia, which aids tumor growth and metastatic spread by remodeling the extracellular matrix and releasing tumor growth factors. For decades, immense efforts have been harnessed toward developing more effective drug delivery systems for pancreatic cancer treatment leveraging nanotechnology, immunotherapy, drug conjugates, and combinations of these approaches. However, despite the reported preclinical success of these approaches, no substantial progress has been made clinically and the prognosis for pancreatic cancer is worsening. This review provides insights into challenges associated with the delivery of therapeutics for pancreatic cancer treatment and discusses drug delivery strategies to minimize adverse effects associated with current chemotherapy options and to improve the efficiency of drug treatment.

Strategies for drug targeting in pancreatic cancer

BACKGROUND

Pancreatic cancer is expected to replace lung cancer as the second greatest cause of cancer mortality by 2025. It has been a particularly the most lethal kind of cancer.

OBJECTIVE

Despite the new innovations, research, and improvements in drug design; there are many hurdles limiting their therapeutic applications such as intrinsic resistance to chemotherapeutics, inability to deliver a sufficient concentration of drug to the target site, lack of effectiveness of drug delivery systems. These are the major contributing factors to limit the treatment. So, the main objective is to overcome these types of problems by nanotechnology and ligand conjugation approach to achieve targeted drug delivery.

METHOD

Nanotechnology has emerged as a major approach to develop cancer treatment. Regardless of the severity, there are several issues that restrict the therapeutic impact, including inadequate transport across biological barriers, limited cellular absorption, degradation, and faster clearance.

RESULT

Targeted drug delivery may overcome these obstacles by binding a natural ligand to the surface of nanocarriers, which enhances the drug's capacity to release at the desired site and minimizes adverse effects.

CONCLUSION

This study will investigate the possible outcomes of targeted therapeutic agent delivery in the treatment of pancreatic cancer, as well as the limitations and future prospects.

C9orf16 represents the aberrant genetic programs and drives the progression of PDAC

Background

Pancreatic ductal adenocarcinoma (PDAC), constituting 90% of pancreatic cancers, is the fourth leading cause of cancer-related deaths in the world. Lack of early detection of PDAC contributes to its poor prognosis as patients are often diagnosed at an advanced stage of disease. This is mostly due to the lack of promising diagnostic and therapeutic targets and corresponding drugs.

Methods and results

Here, by bioinformatic analysis of single cell RNA-sequencing data on normal pancreas tissues, primary and metastatic PDAC tumors, we identified a promising PDAC biomarker, C9orf16. The expression of C9orf16, rarely detectable in normal epithelial cells, was upregulated in primary PDAC cancer cells and was further elevated in metastatic PDAC cancer cells. Gain or loss of function of C9orf16 demonstrated its critical functions in regulating the cell proliferation, invasion and chemotherapy resistance of cancer cells. Pathway analysis and functional studies identified MYC signaling pathways as the most activated pathways in regulating C9orf16 expression and in mediating the development and progression of PDAC.

Conclusions

These data suggested a crucial gene regulation system, MYC-C9orf16, which is actively involved in PDAC development and progression, and targeting this system should be a novel diagnostic and therapeutic target for PDAC.

Imaging Modalities for Early Detection of Pancreatic Cancer: Current State and Future Research Opportunities

Simple Summary

While survival rates for many cancers have improved dramatically over the last 20 years, patients with pancreatic cancer have persistently poor outcomes. The majority of patients with pancreatic cancer are not suitable for potentially curative surgery due to locally advanced or metastatic disease stage at diagnosis. Therefore, early detection would potentially improve survival of pancreatic cancer patients through earlier intervention. Here, we present clinical challenges in the early detection of pancreatic cancer, characterise high risk groups for pancreatic cancer and current screening programs in high-risk individuals. The aim of this scoping review is to investigate the role of both established and novel imaging modalities for early detection of pancreatic cancer. Furthermore, we investigate innovative imaging techniques for early detection of pancreatic cancer, but its widespread application requires further investigation and potentially a combination with other non-invasive biomarkers.

Abstract

Pancreatic cancer, one of the most lethal malignancies, is increasing in incidence. While survival rates for many cancers have improved dramatically over the last 20 years, people with pancreatic cancer have persistently poor outcomes. Potential cure for pancreatic cancer involves surgical resection and adjuvant therapy. However, approximately 85% of patients diagnosed with pancreatic cancer are not suitable for potentially curative therapy due to locally advanced or metastatic disease stage. Because of this stark survival contrast, any improvement in early detection would likely significantly improve survival of patients with pancreatic cancer through earlier intervention. This comprehensive scoping review describes the current evidence on groups at high risk for developing pancreatic cancer, including individuals with inherited predisposition, pancreatic cystic lesions, diabetes, and pancreatitis. We review the current roles of imaging modalities focusing on early detection of pancreatic cancer. Additionally, we propose the use of advanced imaging modalities to identify early, potentially curable pancreatic cancer in high-risk cohorts. We discuss innovative imaging techniques for early detection of pancreatic cancer, but its widespread application requires further investigation and potentially a combination with other non-invasive biomarkers.

Modeling the mechanical stiffness of pancreatic ductal adenocarcinoma

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The PDAC stroma stiffness underlines its malignant behavior and drug resistance.

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3D in vitro cultures must model the PDAC stroma to effectively drug efficacy.

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PSCs are responsible for the stroma, and its activity is increased with TGF-β.

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Develop a 3D culture model of PDAC, which includes PSCs and TGF-β.

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Assess the mechanical stiffness, stain for collagen, and investigate gemcitabine efficacy.

Despite improvements in the understanding of disease biology, pancreatic ductal adenocarcinoma (PDAC) remains the most malignant cancer of the pancreas. PDAC constitutes ∼95% of all pancreatic cancers, and it is highly resistant to therapeutics. The increased tissue rigidity, which stems from the rich fibrotic stroma in the tumor microenvironment, is central to disease development, physiology, and resistance to drug perfusion. Pancreatic stellate cells (PSCs) are responsible for overproduction of extracellular matrix in the fibrotic stroma, and this is exacerbated by the overexpression of transforming growth factor-β (TGF-β). However, there are few in vitro PDAC models, which include both PSCs and TGF-β or mimic in vivo-like tumor stiffness. In this study, we present a three-dimensional in vitro PDAC model, which includes PSCs and TGF-β, and recapitulates PDAC tissue mechanical stiffness. Using oscillatory shear rheology, we show the mechanical stiffness of the model is within range of the PDAC tissue stiffness by day 21 of culture and highlight that the matrix environment is essential to adequately capture PDAC disease. PDAC is a complex, aggressive disease with poor prognosis, and biophysically relevant in vitro PDAC models, which take into account tissue mechanics, will provide improved tumor models for effective therapeutic assessment.

Progress in research of tumor infiltrating lymphocytes in pancreatic cancer

The 5-year survival rate of pancreatic cancer is less than 5%, and the only available treatments, surgery, chemotherapy, and chemoradiation, have shown limited effectiveness. Therefore, alternative treatment strategies are urgently needed. In recent years, tumor infiltrating lymphocyte (TIL) therapy has shown promising successes in the treatment of some types of solid tumors because of its diverse TCR clonality, superior tumor-homing ability, and low off-target toxicity. The significant association between a high TIL density in pancreatic cancer tissue and a good clinical outcome and success of pancreatic cancer-specific TIL expansion ex vivo potentiates the rationality of the TIL therapy in pancreatic cancer. However, there are still many challenges ahead, such as neoantigen screening, rapid cell expansion, and low cytotoxicity. This article reviews the recent advances and limitations of TIL therapy in pancreatic cancer and discusses its future directions.

ERK Inhibition Improves Anti-PD-L1 Immune Checkpoint Blockade in Preclinical Pancreatic Ductal Adenocarcinoma

Patients with pancreatic ductal adenocarcinoma (PDAC) do not benefit from immune checkpoint blockade (ICB) along the PD-1/PD-L1 axis. Variable PD-L1 expression in PDAC indicates a potential access issue of PD-L1-targeted therapy. To monitor target engagement of PD-L1-targeted therapy, we generated a PD-L1-targeted PET tracer labeled with zirconium-89 (89Zr). As the MAPK signaling pathway (MEK and ERK) is known to modulate PD-L1 expression in other tumor types, we used [89Zr]Zr-DFO-anti-PD-L1 as a tool to noninvasively assess whether manipulation of the MAPK signaling cascade could be leveraged to modulate PD-L1 expression and thereby immunotherapeutic outcomes in PDAC. In this study, we observed that the inhibition of MEK or ERK is sufficient to increase PD-L1 expression, which we hypothesized could be leveraged for anti-PD-L1 immune checkpoint therapy. We found that the combination of ERK inhibition and anti-PD-L1 therapy corresponded with a significant improvement of overall survival in a syngeneic mouse model of PDAC. Furthermore, IHC analysis indicates that the survival benefit may be CD8+ T-cell mediated. The therapeutic and molecular imaging tool kit developed could be exploited to better structure clinical trials and address the therapeutic gaps in challenging malignancies such as PDAC.

Increased levels of circulating circular RNA (hsa_circ_0013587) may serve as a novel biomarker for pancreatic cancer

Aim: Circular RNA can serve as a biomarker for early diagnosis of pancreatic cancer. Materials & methods: Analyzed the expression of various differentially expressed circular RNAs in the pancreatic cancer tissues by gene chip and identified the expression of hsa_circ_0013587 in pancreatic cancer cells, tissues and plasma by quantitative reverse transcription PCR (qRT-PCR). Results: Hsa_circ_0013587 was highly expressed in the pancreatic cancer tissues, cell lines and plasma samples from patients with pancreatic cancer. Notably, hsa_circ_0013587 was upregulated in pancreatic cancer patients with later clinical stages III-IV as compared with those detected in early clinical stages I-II. Conclusion: A high expression of hsa_circ_0013587 may serve as a novel diagnostic and therapeutic biomarker for pancreatic cancer.

Identification of Circ_001569 as a Potential Biomarker in the Diagnosis and Prognosis of Pancreatic Cancer

Emerging evidence has shown that circular RNAs (circRNAs) serve as a promising biomarker in different malignancies. Specifically, circ_001569 has been found to be upregulated in some types of human gastrointestinal cancer. In this study, we aimed to investigate clinical significances, diagnostic and prognostic values of circ_001569 in pancreatic cancer (PC), and identify its effects on the malignant behaviors of PC cells. The expression of circ_001569 was determined in 26 tissues samples and 97 plasma samples from PC patients by qRT-PCR. Relationship between circ_001569 expression and clinicopathological parameters was analyzed by Chi-square test. Diagnostic and prognostic values of circ_001569 were evaluated by ROC curves, Kaplan-Meier curves, and Cox regression analysis. The effects of circ_001569 on the proliferation, migration, invasion, and apoptosis of PC cells were assessed by MTT, wound healing, Transwell invasion assays, and flow cytometric analysis, respectively. Results showed that the expression of circ_001569 was upregulated in tissues and plasma of PC patients. High circ_001569 level was positively correlated with lymphatic metastasis, clinical stage, and venous invasion. Circ_001569 level was an independent prognostic indicator for overall survival rates of PC patients, and patients with high circ_001569 level had a poor prognosis. The AUC of circ_001569 was 0.716 (95% CI: 0.642-0.790) with a sensitivity and specificity of 62.76% and 74.29%, respectively. In vitro, circ_001569 silencing decreased cell proliferation, migration, and invasion, but promoted cell apoptosis of PC cells. Our data demonstrate that high circ_001569 level associates with tumor malignant behaviors, and may serve as a potential biomarker in the diagnosis and prognosis of PC.

Prognostic Biomarkers for Pancreatic Ductal Adenocarcinoma: An Umbrella Review

Background: Pancreatic ductal adenocarcinoma (PDAC) leads to the majority of cancer-related deaths due to its morbidity with similar mortality. Lack of effective prognostic biomarkers are the main reason for belated post-operative intervention of recurrence which causes high mortality. Numerous systematic reviews and meta-analyses have explored the prognostic value of biomarkers in PDAC so far. In this article, we performed an umbrella review analyzing these studies to provide an overview of associations between prognostic biomarkers and PDAC survival outcome and synthesized these results to guide better clinical practice.

Methods: Systematic reviews and meta-analyses investigating the associations between PDAC survival outcomes and prognostic biomarkers were acquired via the PubMed and Embase databases from inception till February 1, 2020. Associations supported by nominally statistically significant results were classified into strong, highly suggestive, suggestive, and weak based on several critical factors such as the statistical significance of summary estimates, the number of events, the estimate of the largest study included, interstudy heterogeneity, small-study effects, 95% predictive interval (PI), excess significance bias, and the results of credibility ceiling sensitivity analyses.

Results: We included 41 meta-analyses containing 63 associations between PDAC survival outcomes and prognostic biomarkers. Although, none was supported by strong evidence among these associations, an association between C-reactive protein to albumin ratio (CAR) and PDAC overall survival (OS) and an association between neutrophil-lymphocyte ratio (NLR) and PDAC OS were supported by highly suggestive evidence. Otherwise, the association between lactate dehydrogenase (LDH) and PDAC OS was supported by suggestive evidence. The remaining 60 associations were supported by weak or not suggestive evidence.

Conclusion: Associations between CAR or NLR and PDAC OS were supported by highly suggestive evidence. And the association between LDH and PDAC OS was supported by suggestive evidence. Although the methodological quality of the included systematic reviews and meta-analyses which were evaluated by AMSTAR2.0 is generally poor, the identification of the relatively robust prognostic biomarkers of PDAC may guide better post-operative intervention and follow-up to prolong patients' survival.

Potential diagnostic and therapeutic roles of exosomes in pancreatic cancer

Pancreatic cancer (PaCa) is considered an aggressive but still asymptomatic malignancy. Due to the lack of effective diagnostic markers, PaCa is often diagnosed during late metastatic stages. Besides surgical resection, no other treatment appears to be effective during earlier stages of the disease. Exosomes are related to a class of nanovesicles coated by a bilayer lipid membrane and enriched in protein, nucleic acid, and lipid contents. They are widely present in human body fluids, including blood, saliva, and pancreatic duct fluid, with functions in signal transduction and material transport. A large number of studies have suggested for a crucial role for exosomes in PaCa, which may be utilized to improve its future diagnosis and treatment, but the underlying molecular mechanisms as well as their potential clinical applications are largely unknown. By collecting and analyzing the most up-to-date literature, here we summarize the current progress of the clinical applications related to exosomes in PaCa. Therefore, we presently provide some rationale for the potential value of exosomes in PaCa, thereby promoting putative applications in targeted PaCa treatment.

Phage Display Selection, Identification, and Characterization of Novel Pancreatic Cancer Targeting Peptides

Pancreatic cancer is characterized by a 5-year survival rate of 3%, in part due to inadequate detection methods. The small size of peptides offers advantages regarding molecular targeting. Thus, peptides may be used in detection of pancreatic cancer. Here, peptides that target pancreatic cancer cells were selected using phage display technology using a 15-mer fUSE5 library. Phage were pre-cleared against immortalized pancreatic cells (hTERT-HPNE), followed by selections against pancreatic cancer (Mia Paca-2) cells. Next-generation sequencing identified two peptides, MCA1 and MCA2, with a Log2 fold change (Mia Paca-2/ hTERT-HPNE) >1.5. Modified ELISA and fluorescent microscopy showed that both peptides bound significantly higher to Mia Paca-2 cells, and not to hTERT-HPNE, embryonic kidney (HEK 293), ovarian (SKOV-3) and prostate cancer (LNCaP) cell lines. Further characterization of MCA1 and MCA2 revealed EC₅₀ values of 16.11 µM (95% CI [9.69, 26.31 µM]) and 97.01 µM (95% CI [58.64, 166.30 µM]), respectively. Based on these results, MCA1 was selected for further studies. A competitive dose response assay demonstrated specific binding and an IC₅₀ value of 2.15 µM (95% CI [1.28, 3.62 µM]). Taken together, this study suggests that MCA1 may be used as a pancreatic cancer targeting ligand for detection of the disease.

Contrast-enhanced CT radiomics for predicting lymph node metastasis in pancreatic ductal adenocarcinoma: a pilot study

BACKGROUND

We developed a computational model integrating clinical data and imaging features extracted from contrast-enhanced computed tomography (CECT) images, to predict lymph node (LN) metastasis in patients with pancreatic ductal adenocarcinoma (PDAC).

METHODS

This retrospective study included 159 patients with PDAC (118 in the primary cohort and 41 in the validation cohort) who underwent preoperative contrast-enhanced computed tomography examination between 2012 and 2015. All patients underwent surgery and lymph node status was determined. A total of 2041 radiomics features were extracted from venous phase images in the primary cohort, and optimal features were extracted to construct a radiomics signature. A combined prediction model was built by incorporating the radiomics signature and clinical characteristics selected by using multivariable logistic regression. Clinical prediction models were generated and used to evaluate both cohorts.

RESULTS

Fifteen features were selected for constructing the radiomics signature based on the primary cohort. The combined prediction model for identifying preoperative lymph node metastasis reached a better discrimination power than the clinical prediction model, with an area under the curve of 0.944 vs. 0.666 in the primary cohort, and 0.912 vs. 0.713 in the validation cohort.

CONCLUSIONS

This pilot study demonstrated that a noninvasive radiomics signature extracted from contrast-enhanced computed tomography imaging can be conveniently used for preoperative prediction of lymph node metastasis in patients with PDAC.

Serum Derived Exosomes From Pancreatic Cancer Patients Promoted Metastasis: An iTRAQ-Based Proteomic Analysis

Background

Pancreatic cancer (PC) is one of the most aggressive malignancies and has a poor prognosis despite being extensively researched. The role of serum-derived exosomes in tumorigenesis and the development of PC is still unclear.

Method

The present study employed iTRAQ-based proteomic analysis to search for differences between the serum exosomes of PC patients and those from control patients. Then, bioinformatics methods were used to analyze the functions of the identified proteins, and the possible functions were verified through cell culture experiments.

Results

A total of 611 proteins were identified from exosomes, and 141 proteins were differentially expressed, with 91 up- and 50 down regulated proteins in PC cancer compared to healthy controls. Further analysis indicated that APOE serves as an important hub in the network. In addition, CRP, VWF, APOA2, NIN, and GSK3B potentially interact with many other proteins. We then tested the effect of patient serum-derived exosomes on pancreatic cancer cells and found that patient serum-derived exosomes, but not those from healthy controls, induced cell proliferation, migration, and EMT, supporting the role of exosomes in metastasis.

Conclusion

Our data suggest that exosomes derived from PC patients may promote PC metastasis.

Postoperative metastasis prediction based on portal vein circulating tumor cells detected by flow cytometry in periampullary or pancreatic cancer

Purpose

The aim of this study was to evaluate the value of flow cytometry (FCM) detection of portal vein circulating tumor cells (CTCs) in predicting postoperative metastasis.

Methods

Samples of portal venous blood and peripheral blood were collected from 39 patients during surgery, and CTCs were detected by FCM, with confirmation by laser confocal microscopy and single-cell sequencing.

Results

Among all patients, a portal EpCAM+CD45- percentage ≥24.5×10⁻⁴ (P=0.06), peripheral EpCAM+CD45- count ≥97/5 mL (P=0.034), peripheral EpCAM+CD45- percentage ≥4.4×10⁻⁴ (P=0.042), and CA242≥3.5 U/mL (P=0.027) were significant predictors of metastasis. Further analysis showed that the portal EpCAM+CD45- ratio ≥24.5×10⁻⁴ is a predictor of metastasis (P=0.025) in pancreatic cancer after curative resection.

Conclusion

CTCs detected by FCM in portal venous blood are of significant value for the prediction of postoperative metastasis in pancreatic or periampullary tumors.

Metabolomics identifies serum and exosomes metabolite markers of pancreatic cancer

INTRODUCTION

Pancreatic cancer (PC) is one of the most aggressive malignancies, and it's difficult to diagnosis PC at an early stage, which leads to the poor prognosis of PC.

OBJECTIVES

To identifiy the possible prognosis or dignosis metabolite biomarkers in the serum exosome of PC patients.

METHODS

We employed LC-DDA-MS based untargeted lipidomic analysis to search for potential candidate biomarkers in the serum exosome of PC patients. Then LC-MRM-MS based targeted lipid quantification was used to validate the trends of the candidate biomarkers in larger sample cohorts.

RESULTS

About 270 lipids belonging to 20 lipid species were found significantly dysregulated between the serum exosome of PC patients and healthy controls. 61 of them were validated in larger samples size. We further analysis the correlation between these dysregulated lipids and other PC related factors, and results show that LysoPC 22:0, PC (P-14:0/22:2) and PE (16:0/18:1) are all associated with tumor stage, CA19-9, CA242 and tumor diameter. What's more, PE (16:0/18:1) is also found to be significantly correlated with the patient's overall survival.

CONCLUSION

These data reveal dysregulated lipids in serum exosome of PC patients, which have potential to be biomarkers for diagnosis, or unveil pathological relationship between exosome and PC progress.

Epidemiology of Pancreatic Cancer: Global Trends, Etiology and Risk Factors

Pancreatic cancer is the seventh leading cause of cancer-related deaths worldwide. However, its toll is higher in more developed countries. Reasons for vast differences in mortality rates of pancreatic cancer are not completely clear yet, but it may be due to lack of appropriate diagnosis, treatment and cataloging of cancer cases. Because patients seldom exhibit symptoms until an advanced stage of the disease, pancreatic cancer remains one of the most lethal malignant neoplasms that caused 432,242 new deaths in 2018 (GLOBOCAN 2018 estimates). Globally, 458,918 new cases of pancreatic cancer have been reported in 2018, and 355,317 new cases are estimated to occur until 2040. Despite advancements in the detection and management of pancreatic cancer, the 5-year survival rate still stands at 9% only. To date, the causes of pancreatic carcinoma are still insufficiently known, although certain risk factors have been identified, such as tobacco smoking, diabetes mellitus, obesity, dietary factors, alcohol abuse, age, ethnicity, family history and genetic factors, Helicobacter pylori infection, non-O blood group and chronic pancreatitis. In general population, screening of large groups is not considered useful to detect the disease at its early stage, although newer techniques and the screening of tightly targeted groups (especially of those with family history), are being evaluated. Primary prevention is considered of utmost importance. Up-to-date statistics on pancreatic cancer occurrence and outcome along with a better understanding of the etiology and identifying the causative risk factors are essential for the primary prevention of this disease.

A PET Imaging Strategy for Interrogating Target Engagement and Oncogene Status in Pancreatic Cancer

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) is one of the most deadly cancers, with a 5-year survival rate of less than 10%. Physicians often rely on biopsy or CT to guide treatment decisions, but these techniques fail to reliably measure the actions of therapeutic agents in PDAC. KRAS mutations are present in >90% of PDAC and are connected to many signaling pathways through its oncogenic cascade, including extracellular regulated kinase (ERK) and MYC. A key downstream event of MYC is transferrin receptor (TfR), which has been identified as a biomarker for cancer therapeutics and imaging.

EXPERIMENTAL DESIGN

In this study, we aimed to test whether zirconium-89 transferrin ([⁸⁹Zr]Zr-Tf) could measure changes in MYC depending on KRAS status of PDAC, and assess target engagement of anti-MYC and anti-ERK-targeted therapies.

RESULTS

Mice bearing iKras*p53* tumors showed significantly higher (P < 0.05) uptake of [⁸⁹Zr]Zr-Tf in mice withdrawn from inducible oncogenic KRAS. A therapy study with JQ1 showed a statistically significant decrease (P < 0.05) of [⁸⁹Zr]Zr-Tf uptake in drug versus vehicle-treated mice bearing Capan-2 and Suit-2 xenografts. IHC analysis of resected PDAC tumors reflects the data observed via PET imaging and radiotracer biodistribution.

CONCLUSIONS

Our study demonstrates that [⁸⁹Zr]Zr-Tf is a valuable tool to noninvasively assess oncogene status and target engagement of small-molecule inhibitors downstream of oncogenic KRAS, allowing a quantitative assessment of drug delivery.

A novel plectin/integrin-targeted bispecific molecular probe for magnetic resonance/near-infrared imaging of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest human malignancies with poor patient outcomes often resulting from delayed diagnosis. Therefore, early diagnosis can lead to a better prognosis and improved outcomes. In this study, we have developed a novel conjugate complex of plectin/integrin-targeted bispecific molecular probe, termed Gd-Cy7-PTP/RGD, to be used for magnetic resonance/near-infrared imaging (MRI/NIRF) of pancreatic cancer in vivo. This bispecific molecular probe comprises four parts: Gd(III) for MRI, cyanine 7 (Cy7) for NIRF, the peptide PTP for binding to plectin-1 specifically overexpressed on the surface of PDAC cells, and the peptide RGD for targeting integrin widely expressed on pancreatic duct epithelial cells and angiogenesis. Remarkably, the combination of PTP and RGD greatly increased the targeting efficiency in vitro and in vivo compared to that of either single peptide. Moreover, such bispecific molecular probes target pancreatic neoplasms and angiogenesis simultaneously, producing a "multi-level" targeting effect confirmed by immunofluorescence testing in vitro and in vivo. Under the guidance of MRI/NIRF dual-modality imaging, NIRF-guided delineation of surgical margins during operations was successfully achieved in orthotopic pancreatic cancer. This study promotes further exploration of bispecific molecular probes for clinical application.

The emerging role of circRNAs and their clinical significance in human cancers

Circular RNA (circRNA), a recently discovered subclass of non-coding RNAs (ncRNAs), forms a covalently closed loop with neither a 5' cap structure nor a 3' polyadenylated tail. Generated from precursor mRNA (pre-mRNA) through "backsplicing" (a type of alternative RNA splicing), the majority of circRNAs are located in the cytoplasm and are widespread among living organisms. They are stable and conserved and exhibit spatiotemporal-specific expression. CircRNAs are known to be involved in the development and progression of multiple diseases, including cancer, by acting as microRNA (miRNA) sponges and by regulating processes such as transcription and translation. The extensively aberrant expression profiles of circRNAs in multiple cancerous tissues make these molecules promising diagnostic biomarkers and therapeutic targets for cancer. Here, we briefly review the characteristics, biogenesis, classification, and functions of circRNAs, with a particular focus on the role of circRNAs in various cancers.

Preliminary investigation of the function of hsa_circ_0006215 in pancreatic cancer

The incidence of pancreatic cancer is increasing annually in Asia as a whole. Pancreatic cancer ranks sixth in terms of incidence of all malignant tumors. Circular RNA (circRNA) is a type of non-coding RNA which forms a covalently closed continuous loop. CircRNA is extensively expressed in the cytoplasm, and is markedly conservative and stable. MicroRNA (miR)-378a-3p and human (hsa)_circ_0006215 were detected using the reverse transcription-quantitative polymerase chain reaction (RT-qPCR) in tissue and cells. Western blot analysis detected the SERPINA4 and hsa_circ_0006215 expression in tissue. A Cell Counting Kit-8 assay was used to determine cell stability. Flow cytometry was used to determine the cell apoptotic rate. Transwell assays were used to determine cell migration. hsa_circ_0006215 was identified as a significantly upregulated circRNA. RT-qPCR results verified that, in 30 samples of pancreatic cancer tissue and paracancerous tissue, hsa_circ_0006215 expression was increased in pancreatic cancer tissue, miR-378a-3p expression was decreased in pancreatic cancer tissue, and SERPINA4 expression was increased in pancreatic cancer tissue (P<0.05). Using bioinformatics database and bioinformatics analysis, the interaction network of hsa_circ_0006215 indicated that this circRNA was most likely to regulate the expression of miR-378a-3p. Further interaction analysis revealed that the SERPINA4 gene was a regulatory target gene most likely to have an influence. The present study identified the effects of hsa_circ_0006215, miR-378a-3p and SERPINA4 signaling pathways in pancreatic cancer cells.

Preoperative neutrophil-to-lymphocyte ratio and tumor-related factors to predict lymph node metastasis in patients with pancreatic ductal adenocarcinoma (PDAC)

As a poor prognosis indicator in patients with pancreatic ductal adenocarcinoma (PDCA), lymph node (LN) metastasis is of great importance in treatment. Present study was performed to evaluate the predictive value of preoperative neutrophil-to-lymphocyte ratio (NLR), Platelet-to-lymphocyte ratio (PLR) and possible clinical parameters on the LN metastasis in PDCA patients. A total of 159 operable patients with PDCA were enrolled in our study. The clinical utility of NLR and other clinical parameters was evaluated by receiver operating characteristic (ROC) curves. Overall survival analysis indicated that LN metastasis is an independent prognostic factor. The logistic analysis was used to determine the independent parameters associated with LN metastasis. Ideal cutoff values for predicting LN metastasis are 2.12 for NLR and 130.96 for PLR according to the ROC curve. Multivariate analyses indicate that NLR (HR 2.588; 95% CI 1.246-5.376; P = 0.011), CA125 (HR 6.348; 95% CI 2.056-19.594; P = 0.001) and CA19-9 (HR 2.738; 95% CI 1.151-6.515; P = 0.023) are associated significantly with LN metastasis independently. Preoperative NLR, CA125 and CA19-9 are useful biomarkers for the prediction of LN metastasis in PDCA patients.

CBX7 suppresses cell proliferation, migration, and invasion through the inhibition of PTEN/Akt signaling in pancreatic cancer

Chromobox protein homolog 7 (CBX7), one of the polycomb group (PcG) proteins, is a transcriptional repressor involved in the regulation of cell proliferation and senescence. In the present study, we showed that CBX7 negatively regulates the proliferation, viability, chemoresistance, and migration of pancreatic cancer cells. Overexpression of CBX7 significantly inhibited the proliferation of pancreatic cancer cells in vitro and in vivo. Depletion of CBX7 facilitated their growth. CBX7 also impaired the viability and chemoresistance of pancreatic cancer cells. Transwell assays showed that CBX7 reduces the migratory capacity of pancreatic cancer cells. Of note, CBX7 reduced PTEN/Akt signaling in pancreatic cancer cells by increasing PTEN transcription, suggesting involvement of PTEN/Akt pathway in the tumor suppressive activity of CBX7. In addition, immunohistochemical analysis the CBX7 and PTEN expression in 74 surgically resected pancreatic ductal adenocarcinoma (PDAC) specimens revealed that CBX7 expression is significantly downregulated in pancreatic ductal adenocarcinoma, compared to normal pancreatic tissues. Reduced expression of CBX7 and PTEN was associated with increased malignancy grade in pancreatic adenocarcinoma, whereas maintenance of CBX7 and PTEN expression showed a trend toward a longer survival. These findings suggest CBX7 is an important tumor suppressor that negatively modulates PTEN/Akt signaling during pancreatic tumorigenesis.

The predictive value and role of stromal tumor-infiltrating lymphocytes in pancreatic ductal adenocarcinoma (PDAC)

Recently, increasing evidence has indicated that the presence of tumor infiltrating immune cells has shown predictive significance for many solid tumors. Present study was performed to evaluate the predictive value of stromal tumor-infiltrating lymphocytes (TILs) for the presence of liver metastasis and overall survival in PDAC (pancreatic ductal adenocarcinoma) patients after complete resection and to explore the potential role of lymphocytes in PDAC. A total of 155 resectable patients with PDAC were enrolled in our study. Stromal TIL density was investigated in hematoxylin and eosin-stained sections of surgical specimens and scored. The effect and possible mechanism of lymphocytes on cancer cells was evaluated using co-culture techniques and ELISA test. Stromal TIL negative status (HR = 2.80, 95% CI 1.75-4.48, P < 0.01) was not only an independent predictor of worse OS (HR = 2.7, 95% CI 1.80-4.06, P = <0.01) but also a significant independent predictor of liver metastasis. Higher CEA (P = 0.01) or CA19-9 (P = 0.01) levels were associated with low stromal TIL density. Stromal TIL negative patients appeared to develop tumors with a higher CEA (P = 0.01), larger diameter (P = 0.05) and advanced stage (P = 0.02). The co-culture experiment suggests that lymphocytes can inhibit pancreatic cancer cell proliferation. Further ELISA and cell culture test indicate that lymphocytes may cause pancreatic cancer cells apoptosis through TNF-alpha secretion. Our data suggest a potential favorable role of stromal TILs in predicting liver metastasis and overall survival of patients with PDAC after complete resection. Lymphocytes may inhibit the growth of PDAC through TNF-alpha secretion, which suggest a potential therapeutic approach against PDAC.

Silencing circular RNA hsa_circ_0000977 suppresses pancreatic ductal adenocarcinoma progression by stimulating miR-874-3p and inhibiting PLK1 expression

Circular RNAs (CircRNAs) are a novel type of endogenous noncoding RNAs that regulate target gene expression by interacting with microRNA (miRNA). Emerging evidence shows that dysregulation of circRNAs plays important roles in biological and pathological processes, including cancer development and progression. The functional role of circRNA in PDAC (pancreatic ductal adenocarcinoma) remains to be investigated. In this study, high throughput microarray assay revealed that hsa_circ_0000977 was aberrantly up-regulated in pancreatic cancer tissues; this was also validated by qRT-PCR. Silencing hsa_circ_0000977 suppressed pancreatic cancer cell proliferation and induced cell cycle arrest, which was simulated by hsa-miR-874-3p mimics and blocked by hsa-miR-874-3p inhibitor. Bioinformatics analysis predicted that there is an hsa_circ_0000977/hsa-miR-874-3p/PLK1 (Polo like kinase 1) axis in pancreatic cancer progression. Dual-luciferase reporter system and FISH assay validated the direct interaction of hsa_circ_0000977, hsa-miR-874-3p, and PLK1. Western blot verified that inhibition of hsa_circ_0000977 decreased PLK1 expression. Furthermore, silencing hsa_circ_0000977 suppressed pancreatic cancer growth in vivo. Altogether, silencing hsa_circ_0000977 suppresses progression of pancreatic cancer by interacting with hsa-miR-874-3p and decreasing inhibiting PLK1 expression. Our results may provide a promising strategy for future diagnosis and treatment of pancreatic cancer.

CCAT2 is an oncogenic long non-coding RNA in pancreatic ductal adenocarcinoma

Background

Pancreatic ductal adenocarcinoma (PDAC) is highly aggressive with poor prognosis. Long non-coding RNAs (lncRNAs), a group of non-coding RNAs, play important roles in the progression of PDAC. This study aimed to investigate the potential involvement of lncRNA CCAT2 in PDAC tumorigenesis.

Methods

Expression of CCAT2 was detected by quantitative real-time PCR (qRT-PCR) in 80 human PDAC tissues and three PDAC cell lines. The effects of CCAT2 silencing in PANC-1 cells on cell proliferation and invasion were studied using MTT assay and transwell assay, respectively. The effect of CCAT2 silencing on tumorigenesis was assessed by PANC-1 xenograft in vivo. Using si-KRAS, the role of KRAS to regulate CCAT2 was evaluated by qRT-PCR and luciferase reporter assay. The involvement of MEK/ERK and PI3K/AKT signaling in CCAT2 regulation was investigated by pathway inhibitors PD98059 and LY294002, respectively.

Results

CCAT2 was significantly elevated in high-grade PDAC tissues and higher CCAT2 expression was correlated with lower survival rate in PDAC patients. CCAT2 was up-regulated in PDAC cell lines, as compared with normal pancreatic cells. Silencing of CCAT2 inhibited cell proliferation and invasion in PANC-1 cells in vitro, and attenuated tumorigenesis of PANC-1 xenograft in vivo. Furthermore, CCAT2 was regulated by KRAS through MEK/ERK signaling pathway.

Conclusions

CCAT2 is an oncogenic lncRNA in PDAC likely regulated by the KRAS-MEK/ERK pathway. It could be a potential diagnostic biomarker and therapeutic target for PDAC.

Circular RNA circ-LDLRAD3 as a biomarker in diagnosis of pancreatic cancer

AIM

To analyze the diagnostic value of a circular RNA (circRNA), circ-LDLRAD3, in pancreatic cancer.

METHODS

Expression levels of circ-LDLRAD3 were tested in both cells and clinical samples; the latter included 30 paired pancreatic cancer tissues and adjacent non-tumorous tissues, 31 plasma samples from patients with pancreatic cancer, and 31 plasma samples from healthy volunteers. Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was performed to measure expression levels of circ-LDLRAD3 in cells and clinical samples; then, the relationship between clinicopathological factors of patient samples and expression of circ-LDLRAD3 in pancreatic cancer was analyzed. The diagnostic value of circ-LDLRAD3 was verified by receiver operating characteristic (ROC) curve analysis.

RESULTS

Circ-LDLRAD3 was up-regulated in pancreatic cancer cell lines (P < 0.01), pancreatic cancer tissues (P < 0.01), and plasma samples from patients with pancreatic cancer (P < 0.01). High expression of circ-LDLRAD3 was significantly associated with venous invasion, lymphatic invasion, and metastasis. The area under the ROC curve of circ-LDLRAD3 alone or combination with CA19-9 was 0.67 and 0.87, respectively, with a sensitivity and specificity of 0.5738 (alone) and 0.7049 (alone), and 0.8033 (combination) and 0.9355 (combination), respectively.

CONCLUSION

These data suggest that circ-LDLRAD3 may be a biomarker in the diagnosis of pancreatic cancer.

Imaging in pancreatic disease

Pancreatic diseases, chronic pancreatitis, pancreatic cancer and diabetes mellitus, taken together, occur in >10% of the world population. Pancreatic diseases, as with other diseases, benefit from early intervention and appropriate diagnosis. Although imaging technologies have given clinicians an unprecedented toolbox to aid in clinical decision-making, advances in these technologies and development of molecular-based diagnostic tools could enable physicians to identify diseases at an even earlier stage and, thereby, improve patient outcomes. In this Review, we discuss and identify gaps in the use of imaging techniques for the early detection and appropriate treatment stratification of various pancreatic diseases, including diabetes mellitus, acute and chronic pancreatitis and pancreatic cancer. Imaging techniques discussed are MRI, CT, PET and ultrasonography. Additionally, the identification of new molecular targets for imaging and the development of contrast agents that are able to give molecular information in noninvasive radionuclear imaging and ultrasonography are emerging areas of innovation that could lead to increased diagnostic accuracy and improved patient outcomes.

Novel p21-Activated Kinase 4 (PAK4) Allosteric Modulators Overcome Drug Resistance and Stemness in Pancreatic Ductal Adenocarcinoma

The p21-activated kinase 4 (PAK4) is a key downstream effector of the Rho family GTPases and is found to be overexpressed in pancreatic ductal adenocarcinoma (PDAC) cells but not in normal human pancreatic ductal epithelia (HPDE). Gene copy number amplification studies in PDAC patient cohorts confirmed PAK4 amplification making it an attractive therapeutic target in PDAC. We investigated the antitumor activity of novel PAK4 allosteric modulators (PAM) on a panel of PDAC cell lines and chemotherapy-resistant flow-sorted PDAC cancer stem cells (CSC). The toxicity and efficacy of PAMs were evaluated in multiple subcutaneous mouse models of PDAC. PAMs (KPT-7523, KPT-7189, KPT-8752, KPT-9307, and KPT-9274) show antiproliferative activity in vitro against different PDAC cell lines while sparing normal HPDE. Cell growth inhibition was concurrent with apoptosis induction and suppression of colony formation in PDAC. PAMs inhibited proliferation and antiapoptotic signals downstream of PAK4. Co-immunoprecipitation experiments showed disruption of PAK4 complexes containing vimentin. PAMs disrupted CSC spheroid formation through suppression of PAK4. Moreover, PAMs synergize with gemcitabine and oxaliplatin in vitro KPT-9274, currently in a phase I clinical trial (clinicaltrials.gov; NCT02702492), possesses desirable pharmacokinetic properties and is well tolerated in mice with the absence of any signs of toxicity when 200 mg/kg daily is administered either intravenously or orally. KPT-9274 as a single agent showed remarkable antitumor activity in subcutaneous xenograft models of PDAC cell lines and CSCs. These proof-of-concept studies demonstrated the antiproliferative effects of novel PAMs in PDAC and warrant further clinical investigations. Mol Cancer Ther; 16(1); 76-87. ©2016 AACR.

Epidemiology of pancreatic cancer

Cancer of the pancreas remains one of the deadliest cancer types. Based on the GLOBOCAN 2012 estimates, pancreatic cancer causes more than 331000 deaths per year, ranking as the seventh leading cause of cancer death in both sexes together. Globally, about 338000 people had pancreatic cancer in 2012, making it the 11th most common cancer. The highest incidence and mortality rates of pancreatic cancer are found in developed countries. Trends for pancreatic cancer incidence and mortality varied considerably in the world. A known cause of pancreatic cancer is tobacco smoking. This risk factor is likely to explain some of the international variations and gender differences. The overall five-year survival rate is about 6% (ranges from 2% to 9%), but this vary very small between developed and developing countries. To date, the causes of pancreatic cancer are still insufficiently known, although certain risk factors have been identified, such as smoking, obesity, genetics, diabetes, diet, inactivity. There are no current screening recommendations for pancreatic cancer, so primary prevention is of utmost importance. A better understanding of the etiology and identifying the risk factors is essential for the primary prevention of this disease.

Neutrophils assist the metastasis of circulating tumor cells in pancreatic ductal adenocarcinoma: A new hypothesis and a new predictor for distant metastasis

During our research on circulating tumor cells (CTCs) derived from tumor-adjacent vessels in pancreatic ductal adenocarcinoma (PDAC), we found that CTCs are sometimes surrounded by white blood cells (WBCs) in blood. We hypothesize that such interaction between WBCs and CTCs in blood is a mechanism by which WBCs assist in the metastasis of CTCs. We present our laboratory finding, with our evaluation of the association between the neutrophil-to-lymphocyte ratio (NLR, the most investigated clinical parameter of WBCs) and distant metastasis after curative surgery in PDAC. The laboratory finding was presented through immunofluorescence. In the clinical segment, we performed a retrospective study on PDAC patients with distant metastasis after curative surgery who were referred to Peking University Third Hospital between 2005 and 2014. The data on the possible clinical factors were collected by a retrospective review of the patients' records. Immunofluorescence results showed that CTCs are surrounded by WBCs in tumor-adjacent vessels of PDAC patients. In the clinical segment, 112 (70%) of a total of 160 PDAC patients were found to have developed distant metastases after surgery; among the 112 patients, only 89 had entire data and were enrolled for further analysis (84.3% patients had liver metastasis). No significant association was found between the NLR and overall survival (hazard ratio [HR] = 1.027, 95% confidence interval [CI] 0.723-1.459, P = 0.88); however, a significant relationship between the NLR and distant metastasis after curative surgery was found on the univariate (HR = 1.641, 95% CI 1.058-2.545, P = 0.027) and multivariate analyses (HR = 2.15, 95% CI 1.279-3.615, P = 0.004). Neutrophils might assist in distant metastasis through interaction with CTCs in blood. Moreover, NLR is an effective predictor for distant metastasis after curative surgery for PDAC.

Advances in Biomedical Imaging, Bioengineering, and Related Technologies for the Development of Biomarkers of Pancreatic Disease: Summary of a National Institute of Diabetes and Digestive and Kidney Diseases and National Institute of Biomedical Imaging and Bioengineering Workshop

A workshop sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases and the National Institute of Biomedical Imaging and Bioengineering focused on research gaps and opportunities in the development of new biomarkers of pancreatic disease. The session was held on July 22, 2015, and structured into 6 sessions: 1) Introduction and Overview; 2) Keynote Address; 3) New Approaches to the Diagnosis of Chronic Pancreatitis; 4) Biomarkers of Pain and Inflammation; 5) New Approaches to the Detection of Pancreatic Cancer; and 6) Shed Exosomes, Shed Cells, and Shed Proteins. Recent advances in the fields of pancreatic imaging, functional markers of pancreatic disease, proteomics, molecular and cellular imaging, and detection of circulating cancer cells and exosomes were reviewed. Knowledge gaps and research needs were highlighted. The development of new methods for the noninvasive determination of pancreatic pathology; the use of cellular markers of pancreatic function, inflammation, pain, and malignancy; and the refinement of methods to identify cells and cellular constituents of pancreatic cancer were discussed. The further refinement of sophisticated technical methods and the need for clinical studies to validate these new approaches in large-scale studies of patients at risk for the development of pancreatic disease were repeatedly emphasized.

Pretargeted Immuno-PET of Pancreatic Cancer: Overcoming Circulating Antigen and Internalized Antibody to Reduce Radiation Doses

5B1 is a fully human, monoclonal antibody that has shown promise for the PET imaging of cancers expressing carbohydrate antigen 19.9 (CA19.9)--a carbohydrate prevalent in cells with aberrant glycosylation and an established effector of metastasis. The long physiologic half-life of the antibody and interference from circulating CA19.9 may increase the time required to generate quality images as well as the risk of radiation exposure to healthy tissues during repeated PET imaging. Pretargeting methodologies are an effective approach to expeditiously acquire PET images, but in this case, the pretargeting approach is complicated by the internalization of 5B1 by CA19.9-expressing cells. We sought to adapt and optimize a pretargeting strategy that exploits the bioorthogonal reaction between transcyclooctene (TCO) and tetrazine (Tz) to overcome these complications.

METHODS

5B1 was modified with TCO, and a novel NOTA-PEG7-Tz radioligand was synthesized with the goal of improving on a previously reported analog. BxPC3 and Capan-2 cells were evaluated for their ability to internalize anti-CA19.9 antibodies using a fluorometric assay, and xenografts of the same lines were used for in vivo studies. The pretargeting approach was optimized, and the 2 radioligands were compared using biodistribution and PET imaging in murine models of pancreatic cancer.

RESULTS

BxPC3 and Capan-2 cells were shown to rapidly internalize anti-CA19.9 monoclonal antibodies, including 5B1. (64)Cu-NOTA-PEG7-Tz showed improved in vivo pharmacokinetics relative to (64)Cu-NOTA-Tz using 5B1-TCO as the targeting vector. PET imaging and biodistribution studies showed that injecting the radioligand 72 h after the administration of 5B1-TCO resulted in the best uptake (8.2 ± 1.7 percentage injected dose per gram at 20 h after injection) and tumor-to-background activity concentration ratios. Dosimetry calculations revealed that the pretargeting system produced a greater than 25-fold reduction in total body radiation exposure relative to (89)Zr-desferrioxamine-5B1. PET/CT imaging in an orthotopic Capan-2 xenograft model--which secretes large amounts of CA19.9 and more rapidly internalizes anti-CA19.9 antibodies--showed that this approach is viable even in the difficult circumstances presented by a circulating antigen and internalized targeting vector.

CONCLUSION

The 5B1-TCO and (64)Cu-NOTA-PEG7-Tz system evaluated in these studies can delineate CA19.9-positive xenografts in murine models of pancreatic cancer despite the challenges posed by the combination of circulating antigen and internalization of the 5B1-TCO.

Expression and functional perspectives of miR-184 in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignant tumors, with its 5-year survival rate lower than 5%. MicroRNAs (miR) have been known as important regulators for the tumorigenesis, progression, invasion and metastasis of various cancers. MiR-184 was found to be abnormally expressed in various cancers including glioma and oral carcinoma. The expression and functional role of miR-184 in PDAC, however, remains unclear. PDAC cell line PANC-1 was transfected with miR-184 inhibitor. Real-time PCR was used to detect the expression of miR-184 in untreated PANC-1, miR-184 inhibitor transfected PANC-1 and controlled normal pancreatic ductal epithelial cell line HPDE6c7. MTT assay was used to detect the effect of miR-184 on the proliferation of PANC-1 cells, while invasion assay and Western blotting were employed to describe the effect on cell invasion ability and expression of caspase-3, respectively. In PANC-1 cells, miR-184 was abundantly expressed. The transfection of inhibitor effectively suppressed the expression of miR-184, and further inhibited both cell proliferation and invasion abilities, in addition to the up-regulation of pro-apoptotic protein caspase 3 expression. The up-regulation of miR-184 in PDAC may facilitate the proliferation and invasion ability, and inhibit apoptosis of tumor cells, thus potentiating the occurrence and development of PDAC. MiR-184, therefore, is a potential molecular target for therapy.

PEBP4 promoted the growth and migration of cancer cells in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most common malignancies in the world. Numerous studies have linked the activation of AKT to the progression of PDAC. Phosphatidylethanolamine-binding protein 4 (PEBP4) has been reported to be upregulated in various cancer types. However, its expression pattern and biological functions in PDAC are unknown. In this study, it was found that the messenger RNA (mRNA) and protein level of PEBP4 was elevated in PDAC samples. Forced expression of PEBP4 in PDAC cell lines promoted cell growth and migration, while downregulation of PEBP4 in PDAC cells by RNA interference (RNAi) inhibited the growth, migration, and metastasis of the cancer cells. PEBP4 interacted with AKT and promoted the phosphorylation of serine 473 in AKT. Collectively, this study suggested that PEBP4 might promote the progression of PDAC through activating AKT signaling and PEBP4 might be a promising therapeutic target for PDAC treatment.