Epithelial-mesenchymal Transition In Pancreatic Ductal Adenocarcinoma Research Articles

ZNF263 cooperates with ZNF31 to promote the drug resistance and EMT of pancreatic cancer through transactivating RNF126.

The poor prognosis of pancreatic ductal adenocarcinoma (PDAC) is attribute to the aggressive local invasion, distant metastasis and drug resistance of PDAC patients, which was strongly accelerated by epithelial-mesenchymal transition (EMT). In current study, we systematically investigate the role of ZNF263/RNF126 axis in the initiation of EMT in PDAC in vitro and vivo. ZNF263 is firstly identified as a novel transactivation factor of RNF126. Both ZNF263 and RNF126 were overexpressed in PDAC tissues, which were associated with multiple advanced clinical stages and poor prognosis of PDAC patients. ZNF263 overexpression promoted cell proliferation, drug resistance and EMT in vitro via activating RNF126 following by the upregulation of Cyclin D1, N-cad, and MMP9, and the downregulation of E-cad, p21, and p27. ZNF263 silencing contributed to the opposite phenotype. Mechanistically, ZNF263 transactivated RNF126 via binding to its promoter. Further investigations revealed that ZNF263 interacted with ZNF31 to coregulate the transcription of RNF126, which in turn promoted ubiquitination-mediated degradation of PTEN. The downregulation of PTEN activated AKT/Cyclin D1 and AKT/GSK-3β/β-catenin signaling, thereby promoting the malignant phenotype of PDAC. Finally, the coordination of ZNF263 and RNF126 promotes subcutaneous tumor size and distant liver metastasis in vivo. ZNF263, as an oncogene, promotes proliferation, drug resistance and EMT of PDAC through transactivating RNF126.

PYGL-mediated glucose metabolism reprogramming promotes EMT phenotype and metastasis of pancreatic cancer.

Epithelial-mesenchymal transition (EMT) is closely associated with tumor invasion and metastasis. However, key regulators of EMT in pancreatic ductal adenocarcinoma (PDAC) need to be further studied. Bioinformatics analyses of pancreatic cancer public datasets showed that glycogen phosphorylase L (PYGL) expression is elevated in quasimesenchymal PDAC (QM-PDAC) and positively associated with EMT. In vitro cellular experiments further confirm PYGL as a crucial EMT regulator in PDAC cells. Functionally, PYGL overexpression promotes cell migration and invasion in vitro and facilitates liver metastasis in vivo, while PYGL knockdown has opposite effects. Mechanically, hypoxia induces PYGL expression in a hypoxia inducible factor 1α (HIF1α)-dependent manner and promotes glycogen accumulation. Elevated PYGL mobilizes accumulated glycogen to fuel glycolysis via its activity as a glycogen phosphorylase, thus inducing the EMT process, which could be suppressed by the glycolysis inhibitor 2-deoxy-D-glucose (2-DG). Clinically, PYGL expression is upregulated in PDAC and correlates with its malignant features and poor prognosis. Collectively, the data from our study reveal that the hypoxia/PYGL/glycolysis-induced EMT promotes PDAC metastasis, which establishes the rational for targeting hypoxia/PYGL/glycolysis/EMT signaling pathway against PDAC.

Long Noncoding RNA and Circular RNA: Two Rising Stars in Regulating Epithelial-Mesenchymal Transition of Pancreatic Cancer.

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant tumor with especially poor prognosis. However, the molecular mechanisms of pancreatic oncogenesis and malignant progression are not fully elucidated. Epithelial-mesenchymal transition (EMT) process is important to drive pancreatic carcinogenesis. Recently, long noncoding RNAs (lncRNAs) and circular RNAs(circRNAs) have been characterized to participate in EMT in PDAC, which can affect the migration and invasion of tumor cells by playing important roles in epigenetic processes, transcription, and post-transcriptional regulation. LncRNAs can act as competing endogenous RNAs (ceRNA) to sequester target microRNAs(miRNAs), bind to the genes which localize physically nearby, and directly interact with EMT-related proteins. Currently known circRNAs mostly regulate the EMT process in PDAC also by acting as a miRNA sponge, directly affecting the protein degradation process. Therefore, exploring the functions of lncRNAs and circRNAs in EMT during pancreatic cancer might help pancreatic cancer treatments.

Co‐expression of Zeb‐1 and K17 provides new insights into the role of EMT in pancreatic cancer progression

INTRODUCTIONDespite improvements in screening and therapeutic options, pancreatic ductal adenocarcinoma (PDAC) has the third‐worst mortality rate, highlighting the need for better diagnostic and therapeutic approaches. Epithelial‐mesenchymal transition (EMT) has been conferred with a greater likelihood of metastasis in multiple cancers, specifically identified through markers like Zeb‐1 and Twist‐1. Zeb‐1 (Zinc Finger E‐Box Binding Homeobox 1) was shown to repress E‐cadherin expression, consequently inducing EMT.Our lab has previously identified K17 (Keratin 17) as an independent prognostic biomarker of poor outcomes in PDAC patients. While increasing evidence has suggested that EMT drives pancreatic cancer migration and metastasis, there have not been any well‐established connections between K17 expression and EMT. This study aims to provide new insights into the role of K17 in EMT by evaluating the co‐expression of K17 and Zeb‐1 in human PDAC biopsies. We hypothesized that tumor cells co‐express K17 and Zeb‐1 as a hallmark of EMT in PDAC. In addition, our study aims to establish a novel method of scoring Zeb‐1 expression in stromal fibroblasts via immunofluorescence to remove variability in the stromal constituency.METHODSPDAC tissues obtained from patients who underwent surgical resection between 2013 and 2017 at Stony Brook University (n=20) were selected for serial sectioning. Double immunofluorescence and single immunohistochemical staining were achieved by incubation with Zeb‐1 and K17 antibodies followed by incubation of fluorescent or biotin conjugated secondary antibodies, respectively. Histologic examination was performed using immunofluorescence staining along with H&E and immunohistochemical staining (IHC) to determine concordance.RESULTS● IHC for Zeb‐1 was detected predominantly in the nuclei of centroacinar cells, benign proliferative ducts, and stromal fibroblasts. Focal nuclear staining in tumor epithelial was also detected in some cases.● High levels of K17 and but decreased expression of Zeb‐1 were detected in diffusely infiltrative cells with morphologic features of EMT.● Both high Zeb‐1 and high K17 protein expression were associated with poor survival of PDAC patients.● Using confocal immunofluorescence microscopy, we detected co‐localization of Zeb‐1 and K17 in PDAC.● We quantified Zeb‐1 protein expression in PDAC samples from 20 patients and confirmed significantly higher expression in the tumor‐associated stroma of high‐grade tumors compared to stromal fibroblasts in areas devoid of tumor.CONCLUSIONOur results provide evidence that K17 is upregulated in tumor epithelial cells that show morphologic immunohistochemical properties of EMT. The loss of Zeb‐1 in diffusely infiltrative, K17‐positive tumor cells suggests that EMT upregulates K17, driving tumor aggression. Our results suggest that K17 may enhance PDAC aggression by mediating EMT. Hence, novel therapeutic agents targeting K17 may improve clinical care for this biologically distinct patient subgroup.

Long Non-Coding RNAs in Epithelial-Mesenchymal Transition of Pancreatic Cancer.

Non-coding RNAs (ncRNAs), or RNA molecules that do not code for proteins, are generally categorized as either small or long ncRNA (lncRNA) and are involved in the pathogenesis of several diseases including many cancers. Identification of a large number of ncRNAs could help to elucidate previously unknown mechanisms in phenotype regulation. Some ncRNAs are encapsulated by extracellular vesicles (EVs) and transferred to recipient cells to regulate cellular processes, including epigenetic and post-transcriptional regulations. Recent studies have uncovered novel molecular mechanisms and functions of lncRNAs in pancreatic ductal adenocarcinoma (PDAC), one of the most intractable cancers that is highly invasive and metastatic. As the epithelial-mesenchymal transition (EMT) triggers tumor cell invasion and migration, clarification of the roles of lncRNA in EMT and tumor cell stemness would be critical for improving diagnostic and therapeutic approaches in metastatic cancers. This review provides an overview of relevant studies on lncRNA and its involvement with EMT in PDAC. Emerging knowledge offers evidence for the dysregulated expression of lncRNAs and essential insights into the potential contribution of both lncRNAs and EVs in the pathogenesis of PDAC. Future directions and new clinical applications for PDAC are also discussed.

ACTR3 promotes cell migration and invasion by inducing epithelial mesenchymal transition in pancreatic ductal adenocarcinoma.

Recurrence and metastasis are the major causes of pancreatic ductal adenocarcinoma (PDAC) mortality after treatment. The underlying molecular mechanism is poorly understood. Actin-related protein 3 (ACTR3) is an important component of the actin-related protein 2/3 complex, which is involved in the regulation of cell motility and epithelial mesenchymal transition (EMT) process. Previously published studies have indicated that ACTR3 expression is upregulated in several types of cancers, and promotes tumor development, including gastric cancer and hepatocellular carcinoma. However, to date, the expression levels and the role of ACTR3 in PDAC are not well understood. In the present study, the expression levels of ACTR3 in PDAC tissue and the relationship of ACTR3 expression with clinical prognosis were analyzed by mRNA microarray and bioinformatics. The biological functions and underlying mechanism of ACTR3 in PDAC were examined by a series of assays, including Cell Counting Kit-8 (CCK-8), transwell assay, and Western blotting. We found that the expression of ACTR3 was significantly increased in PDAC tissues and cell lines. A higher expression of ACTR3 was predictive of poor outcome for patients with PDAC. In vitro, the knockdown of ACTR3 expression significantly inhibited the invasive and migratory capacity of PDAC cells, and altered the distribution of F-actin and the expression of EMT markers. The findings of our study indicated that ACTR3 promotes cell migration and invasion by inducing EMT in PDAC, which may be a potential therapeutic target and prognostic indicator for PDAC patients.

PADI1 contributes to EMT in PAAD by activating the ERK1/2-p38 signaling pathway.

Peptidylarginine deiminase 1 (PADI1) has been reported to promote tumorigenesis in breast cancer. However, the functional role of PADI1 in pancreatic ductal adenocarcinoma (PAAD) has remained elusive until now. The expression pattern of PADI1 in PAAD tissues and normal tissues was analyzed using The Cancer Genome Atlas (TCGA) dataset. A Kaplan-Meier curve analysis was performed to evaluate the prognostic value of PADI1 in PAAD patients. PADI1 was knocked down in CFPAN-1 and HPAC cells, and overexpressed in PANC-1 and Bxpc-3 cells by RNA interference. A wound-healing assay was performed to analyze relative cell migration distance. Cell migration and invasion were assessed by a Transwell assay. Related protein expression levels were measured by western blot and immunofluorescence. The bioinformatics analysis showed that PADI1 was overexpressed in PAAD tissues and associated with a poor survival prognosis. The knockdown of PADI1 suppressed cell migration and invasion, and activated the ERK1/2-p38 signaling pathway in CFPAN-1 and HPAC cells. The overexpression of PADI1 produced the opposite results in PANC-1 and Bxpc-3 cells. Additionally, treatment with an MEK1/2 inhibitor significantly attenuated the effects of PADI1 knockdown on cell migration, invasion, the epithelial-mesenchymal transition (EMT) process, and p-ERK1/2 and p38 expression in CFPAN-1 and HPAC cells. Our data suggested that PADI1 may function as an oncogene in regulating metastasis in vitro in PAAD.

Girdin interaction with vimentin induces EMT and promotes thegrowth and metastasis of pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant cancer of the digestive tract that has a high potential for metastasis and a poor prognosis. Girdin was first reported in 2005 as an actin-binding protein and was designated as Akt-phosphorylation enhancer (APE); thus, Girdin has been revealed to have an important role in regulating cancer development. There is additional evidence indicating that Girdin is associated with cell proliferation, migration, invasion and survival in certain cancers. However, the potential mechanisms involving Girdin and mobility in pancreatic cancer have not been elucidated. In the present study, it was revealed that Girdin was highly expressed in pancreatic cancer tissue and was associated with tumor grade. The present study, to the best of our knowledge, is the first aimed at investigating the unknown role of Girdin in PDAC metastasis. A short hairpin RNA for Girdin (sh-Girdin) was successfully constructed with recombinant adenoviral vectors to suppress the expression of Girdin in pancreatic cancer cell lines (PANC-1 and BXPC-3). The silencing efficiency of the Girdin shRNA was determined by RT-qPCR and western blot analysis, and decreased Girdin expression in the cytoplasm was revealed by immunofluorescence detection. Then, sulforhodamine B (SRB) and colony formation assays were used to confirm that the knockdown of Girdin inhibited proliferation in vitro, and Transwell assays were used to examine the influence of Girdin knockdown on cellular mobility. Animal experiments also confirmed that silencing the expression of Girdin in pancreatic cancer cells inhibited the growth and metastasis of pancreatic cancer in vivo. Transforming growth factor-β (TGF-β) is a common inducer of epithelial-mesenchymal transition (EMT) and can effectively induce EMT in PDAC. Notably, TGF-β-treated cells exhibited changes in the classic biological markers of EMT. The expression of E-cadherin, a marker of the epithelial phenotype, increased, and the expression of N-cadherin and vimentin, markers of the interstitial phenotype, decreased in response to sh-Girdin. According to these experiments, Girdin may affect pancreatic cancer progression and development by interacting with vimentin. Therefore, there is evidence indicating that Girdin could be designated as a prognostic biological indicator and a candidate therapeutic target for pancreatic cancer.

MicroRNA-296-5p Promotes Cell Invasion and Drug Resistance by Targeting Bcl2-Related Ovarian Killer, Leading to a Poor Prognosis in Pancreatic Cancer

Background/Aims: Pancreatic ductal adenocarcinoma (PDAC) is characterized by aggressive invasion, early metastasis, and resistance to chemotherapy, leading to a poor prognosis. To clarify the molecular mechanism of these malignant characteristics, we performed a genome-wide microRNA (miRNA) array analysis utilizing micro-cancer tissues from patients with unresectable PDAC (stage IV), obtained by endoscopic ultrasound-fine needle aspiration (EUS-FNA). Methods: The expression profiles of 2,042 miRNAs were determined using micro-cancer tissues from 13 patients with unresectable PDAC obtained by EUS-FNA. The relationship between individual miRNA levels and overall survival (OS) was analyzed. Possible target genes for miRNAs were bioinformatically analyzed using the online database miRDB. Pancreatic cancer cell lines PANC-1, MIA PaCa-2, and PK-8 were transfected with miRNA mimic or small interfering RNA, and cell invasion, epithelial-mesenchymal transition (EMT), and apoptosis markers were examined. miRNA and mRNA expressions were examined by quantitative polymerase chain reaction. Results: Of 2,042 miRNAs, the 10 that exhibited the lowest correlation coefficient (p ≤ 0.005) between miRNA expression level and OS among the patients were identified. The miRDB and expression analysis in cancer cell lines for the 10 miRNAs identified miR-296-5p and miR-1207-5p as biomarkers predictive of shorter survival (p < 0.0005). Bioinformative target gene analysis and transfection experiments with miRNA mimics showed that Bcl2-related ovarian killer (BOK), a pro-apoptotic gene, is a target for miR296-5p in pancreatic cancer cells; transfection of miR-296-5p mimic into PANC-1, MIA PaCa-2, and PK-8 cells resulted in significant suppression of BOK mRNA and protein expression. These transfectants showed significantly higher invasion capability compared with control cells, and knock down of BOK in pancreatic cancer cells similarly enhanced invasion capability. Transfectants of miR-296-5p mimic also exhibited aberrant expression of EMT markers, including vimentin and N-cadherin. Moreover, these transfectants showed a significantly lower apoptosis rate in response to 5-fluorouracil and gemcitabine with a decrease of BOK expression, suggesting a role of miR-296-5p in drug resistance. Conclusion: These results suggest that miR-296-5p is a useful biomarker for a poor prognosis in patients with PDAC, and that the miR-296-5p/BOK signaling axis plays an important role in cell invasion, drug resistance, and EMT in PDACs.

Abstract 1198: Neuropilin-1 blockade chemosensitizes pancreatic cancer cells via dual inhibition of epithelial-mesenchymal transition and autophagy

Abstract Introduction: Fibrotic and malignant pancreatic ductal adenocarcinoma (PDAC) tumors are often resistant to chemotherapy, and remain a leading cause of morbidity and mortality. Epithelial–mesenchymal transition (EMT), a process by which epithelial cells lose their cell polarity and adhesion to become migratory and invasive mesenchymal stem cells, contributes to chemoresistance in PDAC. Likewise, PDAC tumors benefit from autophagy, a self-degradation pathway that confers a survival benefit against metabolic stress. Over-activation of EMT and autophagy has been linked to increased drug resistance in PDAC. Both these processes are largely mediated by TGFβ1. Recently, we demonstrated the role of neuropilin-1 (NRP-1) in TGFβ1-dependent endothelial-mesenchymal transition and fibrosis in PDAC. However, the potential mechanisms linking NRP-1 with EMT and autophagy-mediated chemoresistance remain unexplored. We hypothesized that NRP-1 blockade will enhance chemotherapeutic effect, by suppressing EMT and autophagy in PDAC. Methods: Human PDAC cells (BxPC-3) or serially gemcitabine exposed chemoresistant (CR-BxPC-3) cells were transfected with siNRP-1 or scramble using DharmaFECT-2. For EMT and chemotherapy studies, transfected cells were treated with TGFβ1 (5ng/mL, 24h), followed by gemcitabine (1μM) for 48h. RNA (24h) and protein (48h) was isolated using TRIzolTM and RIPA, respectively. EMT markers were evaluated by RT-PCR and immunoblotting/immunostaining. For autophagy studies, cells were serum starved post NRP-1 silencing and protein was isolated. For autophagy inhibition, cells were treated with bafilomycin-A1 (100nM) for 24h post NRP-1 silencing and protein was isolated. Autophagy flux (LC3-II/I) and P62 were measured by immunoblotting/immunostaining. Cell viability was evaluated by MTT assay. Results: SiNRP-1 treatment in BxPC-3 and CR-BxPC-3 cells resulted in NRP-1 knockdown and promoted cell-death after chemotherapy. TGFβ1-stimulated BxPC-3 cells demonstrated a morphological change consistent with EMT that was revoked by siNRP-1. Also, siNRP-1 maintained epithelial cellular morphology via gain of epithelial and loss of mesenchymal markers. Remarkably, CR-BxPC-3 cells exhibited enhanced EMT features. SiNRP-1 inhibited EMT and promoted cell-death by overcoming gemcitabine resistance in CR-BxPC-3 cells, possibly through reduced ERK signaling. Moreover, siNRP-1 inhibited autophagy (decreased LC3-II/I ratio and increased P62 levels) following starvation or chemotherapy stress, and enhanced cell-death after chemotherapy and autophagy inhibition in BxPC-3 cells. Conclusions: Our findings define a previously undetermined role of NRP-1 in regulating autophagy and TGFβ1-induced EMT in PDAC, suggesting that NRP-1 may represent a novel therapeutic target to overcome chemoresistance through reduced EMT and autophagy. Citation Format: Pratiek N. Matkar, Krishna K. Singh, Gerald Prud’homme, David Hedley, Howard Leong-Poi. Neuropilin-1 blockade chemosensitizes pancreatic cancer cells via dual inhibition of epithelial-mesenchymal transition and autophagy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1198. doi:10.1158/1538-7445.AM2017-1198

Epithelial-mesenchymal transition induction is associated with augmented glucose uptake and lactate production in pancreatic ductal adenocarcinoma.

BackgroundPancreatic ductal adenocarcinoma (PDAC) is a common malignancy with dismal prognosis. Metastatic spread and therapeutic resistance, the main causes of PDAC-related mortalities, are both partially underlined by the epithelial-mesenchymal transition (EMT) of PDAC cells. While the role of Warburg metabolism has been recognized in supporting rapid cellular growth and proliferation in many cancer types, less is known about the metabolic changes occurring during EMT, particularly in the context of PDAC.ResultsIn the current study, experimental models of EMT were established in the Panc-1 cell line of human PDAC via exposure to two physiologically relevant EMT inducers (tumor necrosis factor-α and transforming growth factor-β) and the metabolic consequences examined. The two EMT models displayed similar alterations in the general metabolic profile including augmented glucose uptake and lactate secretion as well as the lack of change in oxidative metabolism. Examination of molecular markers revealed differences in the pathways underlying the metabolic rewiring. 13C-Glucose tracer data confirmed that a major portion of accumulated lactate was derived from glucose, but subsequent flux analysis suggested involvement of non-canonical pathways towards lactate production.ConclusionsOur results characterize the metabolic reprogramming occurring during PDAC cell EMT and highlight the common changes of increased glucose uptake and lactate secretion under different EMT conditions. Such insight is urgently required for designing metabolic strategies to selectively target cells undergoing EMT in PDAC.Electronic supplementary materialThe online version of this article (doi:10.1186/s40170-016-0160-x) contains supplementary material, which is available to authorized users.

CCR7 regulates Twist to induce the epithelial-mesenchymal transition in pancreatic ductal adenocarcinoma.

As reported, the CC chemokine receptor 7 (CCR7) trigger a series of signaling cascades in the epithelial-mesenchymal transition (EMT) of some malignancies. Meanwhile, Twist promotes EMT in pancreatic ductal adenocarcinoma (PDAC) progression. Here, effects of Twist on CCR7-induced EMT in the PDAC were investigated in detail. The immunohistochemistry was used to detect the expression of Twist, and then, in vitro assays were applied. The expression rate of Twist was 72.0% in PDAC samples and closely correlated with tumor-node-metastasis (TNM) stage and invasion. When PDAC cell line PANC1 was subjected to CCL19 stimulation, the expression of p-ERK, p-AKT, Twist, N-cadherin, MMP9, and α-smooth muscle actin (α-SMA) was induced, while the GSK1120212, BEZ235, and MK2206 prohibited the increase of Twist and EMT biomarkers. For another thing, the si-Twist treatment attenuated CCL19-stimulated EMT occurrence, migration, and invasion phenotypes of PANC1 cells. In conclusion, CCR7 pathway up-regulates Twist expression via ERK and PI3K/AKT signaling to manage the EMT of PDAC. Our work allows for clinical gene or protein-targeted regimen of PDAC patients in the near future.

Upregulation of integrin β4 promotes epithelial–mesenchymal transition and is a novel prognostic marker in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDA) is a highly aggressive and often lethal malignant tumor. Several studies have shown that epithelial–mesenchymal transition (EMT) is frequently observed in clinical samples of PDA and is related to high metastatic rates and poor outcomes. To identify candidate molecules regulating EMT in PDA, we previously used cDNA microarray analysis and identified integrin β4 (ITGB4) as one of the genes upregulated in high-EMT xenografts derived from PDA patients. The aim of the current study was to clarify the clinicopathological and functional significance of ITGB4 overexpression in PDA. ITGB4 upregulation in high-EMT xenografts was confirmed by immunohistochemistry. Immunohistochemical analyses of 134 surgically resected PDA cases revealed intratumoral heterogeneity with respect to ITGB4 expression and showed that cancer cells undergoing EMT often display strong diffuse ITGB4 expression. High levels of ITGB4 expression were significantly correlated with the hallmarks of EMT (solitary cell infiltration, reduced E-cadherin expression, and increased vimentin expression), with high tumor grade, and with the presence of lymph node metastasis, and showed an independent prognostic effect. Immunocytochemical analyses of PDA cell lines revealed that localization of ITGB4 changed from regions of cell–cell contact to diffuse cytoplasm and cell edges with occasional localization in filopodia during EMT. Knockdown of ITGB4 reduced the migratory and invasive ability of PDA cells. Overexpression of ITGB4 promoted cell scattering and cell motility in combination with downregulation of E-cadherin and upregulation of vimentin expression. In conclusion, we elucidated the prognostic and clinicopathological significance of ITGB4 overexpression in PDA and also the potential role for ITGB4 in the regulation of cancer invasion and EMT.

MiR-15a inhibits cell proliferation and epithelial to mesenchymal transition in pancreatic ductal adenocarcinoma by down-regulating Bmi-1 expression

PurposesTo investigate whether miR-15a inhibits cell proliferation and epithelial–mesenchymal transition (EMT) in pancreatic ductal adenocarcinoma (PDAC) via the down-regulation of B cell-specific moloney murine leukemia virus insertion site 1 (Bmi-1) expression. Methods and ResultsmiR-15a and Bmi-1 expressions in normal pancreatic tissue and PDAC tissue were measured. The relationship between miR-15a and Bmi-1 expression was analyzed. We found that miR-15a suppressed the expression of Bmi-1 and PDAC cell proliferation; E-cadherin expression was visibly up-regulated after silencing Bmi-1 by transfecting miR-15a into PDAC cell line. ConclusionmiR-15a inhibits cell proliferation and EMT in PDAC via the down-regulation of Bmi-1 expression.

Emerging targets in pancreatic cancer: epithelial&amp;ndash;mesenchymal transition and cancer stem cells

Pancreatic ductal adenocarcinoma is one of the most aggressive solid malignancies and is characterized by poor response to current therapy and a dismal survival rate. Recent insights regarding the role of cancer stem cells (CSCs) and epithelial–mesenchymal transition (EMT) in tumorigenesis have brought further understanding to the field and have highlighted new therapeutic targets. CSCs are a distinct subset of cancer cells, with the ability to differentiate into other cell types and self-renew in order to fuel the maintenance of tumor amplification. Transition of a cancer cell from an EMT leads to increased migratory and invasive properties, and thus facilitates initiation of metastasis. EMT is regulated by a complex network of factors that includes cytokines, growth factors, aberrant signaling pathways, transcription factors, and the tumor microenvironment. There is emerging evidence that the EMT process may give rise to CSCs, or at least cells with stem cell-like properties. We review the key pathways involved in both of these processes, the biomarkers used to identify CSCs, and new therapeutic approaches targeting CSCs and EMT in pancreatic ductal adenocarcinoma.

Role of Epithelial-Mesenchymal Transition in Pancreatic Ductal Adenocarcinoma: Is Tumor Budding the Missing Link?

Pancreatic ductal adenocarcinoma (PDAC) ranks as the fourth commonest cause of cancer death while its incidence is increasing worldwide. For all stages, survival at 5 years is<5%. The lethal nature of pancreatic cancer is attributed to its high metastatic potential to the lymphatic system and distant organs. Lack of effective therapeutic options contributes to the high mortality rates of PDAC. Recent evidence suggests that epithelial-mesenchymal transition (EMT) plays an important role to the disease progression and development of drug resistance in PDAC. Tumor budding is thought to reflect the process of EMT which allows neoplastic epithelial cells to acquire a mesenchymal phenotype thus increasing their capacity for migration and invasion and help them become resistant to apoptotic signals. In a recent study by our own group the presence and prognostic significance of tumor budding in PDAC were investigated and an association between high-grade budding and aggressive clinicopathological features of the tumors as well as worse outcome of the patients was found. The identification of EMT phenotypic targets may help identifying new molecules so that future therapeutic strategies directed specifically against them could potentially have an impact on drug resistance and invasiveness and hence improve the prognosis of PDAC patients. The aim of this short review is to present an insight on the morphological and molecular aspects of EMT and on the factors that are involved in the induction of EMT in PDAC.