Transition In Pancreatic Ductal Adenocarcinoma Research Articles

Immunohistochemical characteristics of epithelial-mesenchymal transition in pancreatic ductal adenocarcinoma

The epithelial-mesenchymal transition (EMT) plays a crucial role in the development of pancreatic ductal adenocarcinoma (PDAC). There are insufficient and contradictory data in the scientific literature on the peculiarities of epithelial and mesenchymal marker expression in PDAC ducts and EMT zone, which requires further research on the role of EMT in the development and progression of PDAC. Aim: to conduct a comprehensive assessment of epithelial and mesenchymal markers of EMT in the PDAC ducts and EMT zone at different degrees of differentiation. Materials and methods. A comprehensive pathomorphological and immunohistochemical examination including 49 cases of surgical material from patients with PDAC, divided into groups of moderate (G2) and low degree of tumor differentiation (G3). Results. PDAC was characterized by low levels of E-cadherin expression in both ducts and EMT – Me = 22.58 % [12.81; 36.23] and Me = 25.17 % [19.04; 35.37], respectively (p > 0.05). Only membrane expression of the marker was detected in the ducts and membrane-cytoplasmic one – in the EMT zone without significant differences in the groups. There was a significant decrease in the ductal β-catenin expression (p < 0.05) in G2 with membrane-cytoplasmic staining (Me = 15.58 % [10.42; 26.24]), in G3 – with membrane (Me = 4.42 % [2.35; 5.93]); in the EMT zone, only membrane-cytoplasmic expression was observed in both groups without significant difference (p > 0.05). Membrane expression of CK7 was positive in 100 % of PDAC, significantly lower at G2 (Me = 19.51 % [10.70; 27.24]; Me = 26.19 % [20.93; 30.05], p < 0.05), and CK18 (Me = 21.34 % [9.68; 29.96] – in G2, in G3 – Me = 22.50 % [8.24; 40.08], p > 0.05). Expression of α-SMA and Vim was seen in spindle-shaped stromal cells, around tubular and trabecular structures with membrane-cytoplasmic staining. There was no significant difference between α-SMA in G2 and G3, the level of vimentin was significantly lower in G3 (p < 0.05). Conclusions. The features of PDAC E-cadherin, β-catenin, CK7 and CK18 marker expression indicate a greater EMT process at the periphery of the tumor and its severity increases with tumor progression. The optimal markers to determine the mesenchymal phenotype of PDAC cells are α-SMA and vimentin.

Abstract B023: Hypoxia supports CAF-mediated epithelial-mesenchymal transition in pancreatic ductal adenocarcinoma

Abstract The pancreatic ductal adenocarcinoma (PDAC) microenvironment is populated by distinct subtypes of cancer-associated fibroblasts (CAFs), including myofibroblastic CAFs (myCAFs) that synthesize and remodel the stromal matrix and inflammatory CAFs (iCAFs) that secrete cytokines and growth factors. Subpopulations of CAFs reside in regions of tumor hypoxia, which may play a role in determining CAF behaviors. We tested the hypothesis that iCAFs preferentially drive ductal cell epithelial-mesenchymal transition (EMT), which promotes PDAC chemoresistance, and that hypoxia promotes the iCAF phenotype. Cell-cell communication analysis using publicly available single-cell RNA sequencing (scRNA-seq) data of human tumors indicated that iCAFs secrete growth factors predicted to promote ductal cell EMT. This inference was confirmed in experiments showing that PDAC cells exhibit stronger EMT in response to conditioned medium from iCAFs than from myCAFs. Publicly available scRNA-seq data further indicated a correlation between hypoxia and the iCAF phenotype. qRT-PCR and immunofluorescence microscopy confirmed that hypoxia promotes the iCAF phenotype, and conditioned medium experiments demonstrated the preferential ability of hypoxic CAFs to utilize an NFκB-dependent pathway to secrete cytokines that promote EMT. A screen of 430 kinase inhibitors nominated specific growth factors that we validated to be EMT-inducing and generated by hypoxic CAFs. Finally, iterative indirect immunofluorescence imaging (4i) of tumor sections from KrasLSL-G12D/+; Trp53LSL-R172H/+, Pdx1-Cre; Rosa26YFP/YFP (KPCY) mice and quantitative image analysis demonstrated a spatial correlation in PDAC tumors between mesenchymal neoplastic cells and hypoxic CAFs. Our results raise the intriguing possibility that hypoxia cooperates with CAFs to promote EMT in PDAC and identify drug targets whose antagonism may interfere with a PDAC-stromal signaling process that promotes chemoresistance. Citation Format: Karl Kowalewski, Matthew Lazzara. Hypoxia supports CAF-mediated epithelial-mesenchymal transition in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr B023.

Hsa_circ_0084003 modulates glycolysis and epithelial-mesenchymal transition in pancreatic ductal adenocarcinoma through targeting hsa-miR-143-3p/DNMT3A axis.

Pancreatic ductal adenocarcinoma, one of the deadliest tumors of the digestive tract, is a difficult and invasive malignancy. Current treatment for pancreatic ductal adenocarcinoma mainly depends on surgery combined with radiotherapy and chemotherapy, which, however, often resulting in questionable curative effect. Therefore, new targeted therapies are needed in future treatment. We first interfered with hsa_circ_0084003 expression in pancreatic ductal adenocarcinoma cells, and further studied how hsa_circ_0084003 functioned in regulating pancreatic ductal adenocarcinoma cell aerobic glycolysis and epithelial-mesenchymal transition, and also evaluated the regulatingeffect of hsa_circ_0084003 on hsa-miR-143-3p and its target DNA methyltransferase 3A. Hsa_circ_0084003 knockdown could notably inhibit the aerobic glycolysis and epithelial-mesenchymal transition of pancreatic ductal adenocarcinoma cells. Mechanistically, hsa_circ_0084003 could regulate its downstream target DNA methyltransferase 3A by binding to hsa-miR-143-3p, and overexpression of hsa_circ_0084003 could reverse the anticarcinogenic effect of hsa-miR-143-3p on aerobic glycolysis and epithelial-mesenchymal transition in pancreatic ductal adenocarcinoma cells. Hsa_circ_0084003, as a carcinogenic circular RNA, regulated its downstream target DNA methyltransferase 3A to promote pancreatic ductal adenocarcinoma cell aerobic glycolysis and epithelial-mesenchymal transition through sponging hsa-miR-143-3p. Therefore, hsa_circ_0084003 could be studied as a possible therapeutic target regarding pancreatic ductal adenocarcinoma.

Notch signaling regulates vasculogenic mimicry and promotes cell morphogenesis and the epithelial-to-mesenchymal transition in pancreatic ductal adenocarcinoma.

Vasculogenic mimicry (VM) is the process where cancer cells adopt endothelial characteristics by forming tube-like structures and perfusing channels. This phenomenon has been demonstrated in several types of solid tumors and associated with the growth and survival of tumor cells. In this study, we investigated the presence of VM formation in human pancreatic ductal adenocarcinoma (PDAC) and elucidated the molecular mechanisms underlying the VM process. In human PDAC tissues, CD31-negative, periodic acid-Schiff (PAS)-positive channels were predominantly found in desmoplastic areas, which are generally also hypovascularized. We found a positive correlation of VM capacity to tumor size and NOTCH1 expression and nuclear localization with statistical significance, implicating that Notch activity is involved with VM formation. Additionally, our data showed that the presence of growth or angiogenic factors significantly increased Notch activity in PDAC cell lines and upregulated several mesenchymal marker genes, such as TWIST1 and SNAI1, which can be inhibited by a gamma-secretase inhibitor. Our data showed that Notch signaling plays an important role in inducing VM formation in PDAC by promoting the epithelial-to-mesenchymal transition process.

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.

Laminin‑332 mediates proliferation, apoptosis, invasion, migration and epithelial‑to‑mesenchymal transition in pancreatic ductal adenocarcinoma.

The poor prognosis of patients with pancreatic ductal adenocarcinoma (PDAC) is primarily due to the invasive and metastatic behaviors of this disease. Laminin-332 (LM-332) is a key component of the basement membrane barrier, and is associated with tumor metastasis. The present study provides evidence towards the potential function of LM-332 in carcinoma, indicating the distinct roles of the three LM-332 subunits (α3, β3 and γ2) in cell proliferation, migration, invasion, apoptosis and the epithelial-to-mesenchymal transition (EMT) in cancer. The roles of the α3, β3 and γ2 subunits in the malignant biological behavior of PDAC were investigated in the present study. It was revealed that the α3, β3 and γ2 subunits were upregulated in PDAC. Inhibition of all LM-332 subunits abrogated the tumorigenic outcomes, which included cell proliferation, apoptosis, invasion, migration and EMT in vitro. However, the three LM-332 subunits had different degrees of effects on biological behavior. It was observed that LAMA3 (α3) had a stronger effect on cell proliferation, migration and invasion. In addition, LAMB3 (β3) knockdown significantly increased E-cadherin levels and decreased vimentin levels, indicating that LAMB3 was associated with EMT. Likewise, LAMC2 (γ2) mediated proliferation, apoptosis, invasion and migration. However, small interfering (si)-LAMC2 promoted the progression of EMT, which was the opposite effect to that of si-LAMB3. The LM-332 subunits (α3, β3 and γ2) may be novel therapeutic targets of PDAC in the future.

A nicotine-induced positive feedback loop between HIF1A and YAP1 contributes to epithelial-to-mesenchymal transition in pancreatic ductal adenocarcinoma

BackgroundNicotine, an active ingredient in tobacco, can promote epithelial-to-mesenchymal transition (EMT) processes that enhance the aggressiveness of a number of human cancers. In the present study, we investigated whether cigarette smoke/nicotine drives EMT in pancreatic ductal adenocarcinoma (PDAC).MethodsQuantitative real-time PCR, western blot, immunohistochemistry, and immunofluorescence assays were used to evaluate Yes-associated protein 1 (YAP1) expression associated with cigarette smoking in human PDAC tissue samples and with nicotine exposure in PDAC cell lines. Bioinformatics, loss- and gain- of- function experiments, luciferase reporter assays, chromatin immunoprecipitation (ChIP), and murine tumor xenograft models were performed to examine the function of YAP1 in PDAC and to identify potential mechanisms of action.ResultsExposure to smoking or nicotine promoted EMT and tumor growth in PDAC cells and in xenograft tumors. Functional studies revealed that YAP1 might drive nicotine-stimulated EMT and oncogenic activity in vitro and in vivo. In human PDAC tissues, upregulation of YAP1 was associated with “ever smoking” status and poor overall survival. In term of mechanism, hypoxia inducible factor (HIF)1A promoted YAP1 nuclear localization and YAP1 transactivation by directly binding to the hypoxia responsive elements of the YAP1 promoter upon nicotine treatment. Nicotine stimulated HIF1A and YAP1 expression by activating cholinergic receptor nicotinic alpha7 (CHRNA7). In addition, YAP1 increased and sustained the protein stability of HIF1A.ConclusionsThese data demonstrate that YAP1 enhances nicotine-stimulated EMT and tumor progression of PDAC through a HIF1A/YAP1 positive feedback loop. Developing inhibitors that specifically target YAP1 may provide a novel therapeutic approach to suppress PDAC growth, especially in PDAC patients who have a history of smoking.

Silencing ubiquitin-conjugating enzyme 2C inhibits proliferation and epithelial-mesenchymal transition in pancreatic ductal adenocarcinoma.

Ubiquitin-conjugating enzyme 2C (UBE2C) is a core ubiquitin-conjugating enzyme in the ubiquitin-proteasome system that promotes cell cycle progression. Previous studies have indicated that UBE2C mediates tumorigenesis and progression in various cancers, but its role in pancreatic ductal adenocarcinoma (PDAC) remains unclear. This study elucidated the function of UBE2C in PDAC tumorigenesis and progression by determining UBE2C expression via real-time qPCR, western blotting and immunohistochemistry. The associations between UBE2C expression and clinicopathological characteristics and survival were assessed using a tissue microarray based on a multicentre PDAC cohort. We found that UBE2C was strongly expressed in PDAC patient tissues and was negatively associated with clinical stage, lymph node metastasis, perineural invasion and survival (all P<0.05). Multivariate analysis revealed that high UBE2C expression is an independent risk factor for PDAC (P=0.001). In the PDAC cell lines CFPAC-1 and Panc-1, silencing UBE2C suppressed cell proliferation by inducing G1/S arrest mediated by downregulation of cyclin D1. Furthermore, UBE2C knockdown decreased the migration of PDAC cells invitro by downregulating epithelial-mesenchymal transition (EMT). RNA-seq analysis showed that upon silencing UBE2C in CFPAC-1 cells, cyclin D1 and vimentin were downregulated by approximately 3.5-fold and 2.6-fold, respectively, and the major enriched pathways were related to cell cycle progression. Experiments on tumour-bearing mice injected with CFPAC-1 cells indicated that UBE2C depletion significantly inhibits tumour growth invivo. These results suggest that UBE2C is involved in the development and progression of PDAC by regulating cell proliferation and EMT. UBE2C is a novel potential therapeutic target for pancreatic cancer. DATABASE: Data are available in the GEO database under accession number GSE137172.

High expression of WNT7A predicts poor prognosis and promote tumor metastasis in pancreatic ductal adenocarcinoma

Due to the therapy resistance and frequent metastasis, pancreatic ductal adenocarcinoma(PDAC) remains one of the most malignant carcinoma. WNT7A, an important ligand of Wnt/β-catenin signaling pathways, has a controversial role in tumor development. The role of WNT7A in PDAC remains unclear. In this study, we analyzed the expression pattern of WNT7A at mRNA and protein levels. We found pancreatic cancer tissue demonstrated a significant high WNT7A expression compared with the adjacent non-tumor tissue and the expression of WNT7A positively correlates with poor prognosis and lymph node metastasis. Then, we performed transwell assays and wound healing assays in vitro and found that WNT7A promotes the migration capacity of cancer cells. Furthermore, we explored the underlying mechanism of the WNT7A inducing cell migration. Results showed that up-regulated WNT7A expression inducing higher expression of N-cadherin and lower expression of E-cadherin while the contrast result was shown in the WNT7A knock-down group, which suggested that WNT7A might contribute to an epithelial–mesenchymal transition. Finally, we found that the hypoxia culture condition remarkably increased the WNT7A expression. In conclusion, our work demonstrated that hypoxia induced high expression of WNT7A might promote the cell migration via enhancing the epithelial–mesenchymal transition in PDAC.

Abstract 5741: Dexamethasone suppresses cytokine-induced dual oxidase 2 and VEGF-A expression in human pancreatic cancer cells in vitro and pancreatic cancer growth in xenografts

Abstract Chronic pancreatic inflammation is strongly associated with pancreatic cancer. We previously demonstrated that inflammatory cytokines interact to produce a DUOX2 -dependent, reactive oxygen species (ROS)-related, pro-oxidant milieu that could increase the pathologic potential of pancreatic inflammation, enhancing malignant transformation. Furthermore, we have shown that DUOXuox2 expression is upregulated in patients with chronic pancreatitis as well as pancreatic ductal adenocarcinoma (PDAC). Dexamethasone (Dex) has been reported to inhibit PDAC invasiveness, the formation of pancreatic intraepithelial neoplasia in genetically-engineered mouse models of pancreatic cancer, as well as epithelial to mesenchymal transition in PDACs, and local tumor recurrence and metastasis in vivo. Using cultured human pancreatic cancer cell lines, we found that in a dose- and time-dependent fashion Dex inhibited cytokine (IFN-γ/LPS, IL-4, and IL-17)-mediated up-regulation of DUOXuox2 and VEGF-A expression in several human pancreatic cancer cell lines, including BxPC-3, ASPC-1, and CFPAC-1. Dex pretreatment also blocked DUOX2-related DNA double strand breaks (detected as activated γH2AX) and the expression of HIF-1α in PDAC cells treated with pro-inflammatory cytokines. The effects of Dex were abolished by pre-treatment with the Dex antagonist RU-486. As expected, we did not observe anti-proliferative effects of Dex on PDAC cells in vitro. However, Dex strongly repressed DUOXuox2 mRNA and protein expression as well as the growth of xenografts initiated from BxPC-3 cells; in contrast, for the MIA-Paca line that is unresponsive to cytokines in culture, Dex produced no effect on DUOXuox2 expression and tumor growth when these cells were grown as xenografts. Examination of the human DUOXuox2 promotor in silico revealed a putative negative glucocorticoid receptor (GR) binding element. Western analysis, using nuclear extracts from pancreatic cancer cells treated with Dex, revealed that both activated glucocorticoid receptor and certain co-repressors, such as NCOR-1/2 and histone deacetylases (HDAC1, 2, and 3) exist in human pancreatic cancer cell nuclei. Our ongoing experiments are focused on understanding the molecular mechanism of Dex-mediated DUOXuox2 repression both in vitro and in vivo. In summary, these studies suggest that cytokine-related oxidant stress, generated by Duox2, could play a role in the progression of pancreatic cancer. Citation Format: Yongzhong Wu, James H. Doroshow. Dexamethasone suppresses cytokine-induced dual oxidase 2 and VEGF-A expression in human pancreatic cancer cells in vitro and pancreatic cancer growth in xenografts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5741.

Tumor budding is a prognostic factor linked to epithelial mesenchymal transition in pancreatic ductal adenocarcinoma. Study report and literature review

BackgroundPancreatic ductal adenocarcinoma (PDAC) has a devastatingly poor prognosis. Surgical resection is undertaken in only 20% of patients. Most of well-known prognostic factors reflect tumor stage more than its biology. So it is important to identify new biological indicators related to survival in order to develop new therapies. ObjectiveTo determine the relation between tumor budding and Epithelial Mesenchymal Transition (EMT) and to evaluate their impact on survival for patients after resection of PDAC. MethodsWe herein report a retrospective study of 50 patients with resected PDAC. Tumor budding, immunohistochemical expression of vimentin and other standard factors were correlated with survival using the Kaplan-Meier method and Cox multivariable survival analysis. For tumor budding assessment, an inter-observer variability study was performed using 100 images of tumor slides stained with Hematoxylin & Eosin and Pan-Cytokeratin. ResultsTumor budding was present in all tumors. A substantial agreement between six pathologists was established in distinguishing high-grade from low-grade budding (κ = 0.6 and 0.73 for H&E and PCK images respectively). High-grade budding was identified in 56% of tumors (28/50). It was an adverse prognostic factor independent of tumor size, resection margins status, nodal status and vascular invasion (p = 0.008). Tumor budding was significantly associated with vimentin expression (p = 0.002). ConclusionsThe association of tumor budding with vimentin expression supported the idea that EMT is a key process in PDAC responsible for progression and drug resistance. Consequently, the elucidation of EMT molecular biology and development of new targeted therapy may improve disease outcome.

Abstract 4071: FGFR1 inhibitor reverses Smoothened inhibition-induced epithelial-to-mesenchymal transition in pancreatic ductal adenocarcinoma

Abstract The majority of Pancreatic cancer (PaCA) patients present with metastatic disease and receive little benefit from chemotherapy. Although nanoparticulate carriers can potentially deposit sustained and high doses of chemotherapeutics in tumors, PaCA tumors are poorly perfused, which limits drug deposition. Ten days of oral dosing with NVP-LDE225 (40 mg/kg), an inhibitor of the sonic hedgehog (SHH) pathway (sHHI), increased tumor deposition of blood-borne, fluorescently labeled, sterically-stabilized lipidic (SSL) nanoparticles by enhancing the perfusion and permeability of the otherwise-impermeable microvasculature of PaCA patient-derived xenograft (PDX) tumors. However, literature indicates sHH ablation is associated with increased Epithelial-to-Mesenchymal (EMT) transition and invasiveness in PaCA. Here we investigated the compensatory role of FGFR1 in sHHI-induced tumor progression. Four to 8 daily treatments with the sHHI resulted in no significant reduction of tumor volume, but markedly increased the ratio of tumor cells (human mitochondria+) to Collagen1 in the stroma, in two s.c. low-passage PDX models of varying stromal content. Immunostaining of sHHI-treated tumors revealed no alteration in total FGFR1 expression, but showed a significant elevation in the (1) percent of FGFR1+ pixels correlating with DAPI+ nuclei in tumor (human mitochondria+) cells and stromal cells, (2) number of vimentin+ (EMT) cells, and (3) proliferative index marked by Ki67+ nuclei, compared to controls, suggesting accelerated tumor progression. Nuclear FGFR1 was associated with vimentin+ cells, but was excluded from the nuclei of Ki67+ cells in all groups, implicating nuclear translocation of FGFR1 in EMT. NVP-BGJ398, a small-molecule pan-FGFR inhibitor (FGFRI), administered p.o. for 3 days (15 mg/kg/day) after 7d of sHHI-pretreatment (1) significantly reduced nuclear localization of FGFR1 compared to sHHI-treated animals, (2) reversed the ratio of human mitochondria+ tumor cells to Collagen 1+ stroma, (3) depleted vimentin+ structures by &amp;gt;2 fold, and (4) reduced Ki67+ cells to control levels. FGFRI without sHHI-pretreatment resulted in decreased nuclear FGFR1 relative to controls, but did not impact proliferation, EMT, or tumor cell-to-stroma ratio. Finally, the sHHI/FGFRI sequence increased functional (FITC-L. esculentum lectin+) tumor vessel density and area the perfused by vascular permeability probes (fluorescent SSL) compared to both controls and sHHI-treated animals. FGFRI administration in vehicle-treated controls had no impact on vascular permeability or perfusion. We conclude that the combination of sHHI in sequence with FGFRI may reverse potentially deleterious effects of sHHI and mediate a transient enhancement of tumor permeability, and increase deposition and penetration of nanoparticulate SSL drug formulations into pancreatic cancers. Citation Format: Tista Roy Chaudhuri, Qingxiang Lin, Ninfa L. Straubinger, Wen Wee Ma, Robert M. Straubinger. FGFR1 inhibitor reverses Smoothened inhibition-induced epithelial-to-mesenchymal transition in pancreatic ductal adenocarcinoma [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 4071. doi:10.1158/1538-7445.AM2017-4071

Inflammation and Epithelial-Mesenchymal Transition in Pancreatic Ductal Adenocarcinoma: Fighting Against Multiple Opponents.

Pancreatic ductal adenocarcinoma (PDAC) is the most common type of pancreatic cancer and one of the most lethal human cancers. Inflammation is a critical component in PDAC initiation and progression. Inflammation also contributes to the aggressiveness of PDAC indirectly via induction of epithelial-mesenchymal transition (EMT), altogether leading to enhanced resistance to chemotherapy and poor survival rates. This review gives an overview of the key pro-inflammatory signaling pathways involved in PDAC pathogenesis and discusses the role of inflammation in induction of EMT and development of chemoresistance in patients with PDAC.

Epithelial-To-Mesenchymal Transition in Pancreatic Ductal Adenocarcinoma: Fiction or Fact?

Epithelial-To-Mesenchymal Transition in Pancreatic Ductal Adenocarcinoma: Fiction or Fact?

Epithelial-to-mesenchymal transition in pancreatic ductal adenocarcinoma: Characterization in a 3D-cell culture model.

To analyze the effect of three-dimensional (3D)-arrangement on the expression of epithelial-to-mesenchymal transition markers in pancreatic adenocarcinoma (PDAC) cells. HPAF-II, HPAC, and PL45 PDAC cells were cultured in either 2D-monolayers or 3D-spheroids. Ultrastructure was analyzed by transmission electron microscopy. The expression of E-cadherin, β-catenin, N-cadherin, collagen type I (COL-I), vimentin, α-smooth muscle actin (αSMA), and podoplanin was assayed by confocal microscopy in cells cultured on 12-mm diameter round coverslips and in 3D-spheroids. Gene expression for E-cadherin, Snail, Slug, Twist, Zeb1, and Zeb2 was quantified by real-time PCR. E-cadherin protein level and its electrophoretic pattern were studied by Western blot in cell lysates obtained from cells grown in 2D-monolayers and 3D-spheroids. The E-cadherin/β-catenin complex was expressed in a similar way in plasma membrane cell boundaries in both 2D-monolayers and 3D-spheroids. E-cadherin increased in lysates obtained from 3D-spheroids, while cleavage fragments were more evident in 2D-monolayers. N-cadherin expression was observed in very few PDAC cells grown in 2D-monolayers, but was more evident in 3D-spheroids. Some cells expressing COL-I were observed in 3D-spheroids. Podoplanin, expressed in collectively migrating cells, and αSMA were similarly expressed in both experimental conditions. The concomitant maintenance of the E-cadherin/β-catenin complex at cell boundaries supports the hypothesis of a collective migration for these cells, which is consistent with podoplanin expression. We show that a 3D-cell culture model could provide deeper insight into understanding the biology of PDAC and allow for the detection of marked differences in the phenotype of PDAC cells grown in 3D-spheroids.

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.

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.

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.

Prolyl-hydroxylase 3 silencing correlates with epithelial to mesenchymal transition in pancreatic ductal adenocarcinoma

Journal of the American College of Surgeons 215(3):p S131, September 2012. | DOI: 10.1016/j.jamcollsurg.2012.06.339

Epithelial-to-Mesenchymal Transition in Pancreatic Ductal Adenocarcinoma and Pancreatic Tumor Cell Lines: The Role of Neutrophils and Neutrophil-Derived Elastase

Pancreatic ductal adenocarcinoma (PDAC) is frequently associated with fibrosis and a prominent inflammatory infiltrate in the desmoplastic stroma. Moreover, in PDAC, an epithelial-to-mesenchymal transition (EMT) is observed. To explore a possible connection between the infiltrating cells, particularly the polymorphonuclear neutrophils (PMN) and the tumor cell transition, biopsies of patients with PDAC (n = 115) were analysed with regard to PMN infiltration and nuclear expression of β-catenin and of ZEB1, well-established indicators of EMT. In biopsies with a dense PMN infiltrate, a nuclear accumulation of β-catenin and of ZEB1 was observed. To address the question whether PMN could induce EMT, they were isolated from healthy donors and were cocultivated with pancreatic tumor cells grown as monolayers. Rapid dyshesion of the tumor cells was seen, most likely due to an elastase-mediated degradation of E-cadherin. In parallel, the transcription factor TWIST was upregulated, β-catenin translocated into the nucleus, ZEB1 appeared in the nucleus, and keratins were downregulated. EMT was also induced when the tumor cells were grown under conditions preventing attachment to the culture plates. Here, also in the absence of elastase, E-cadherin was downmodulated. PMN as well as prevention of adhesion induced EMT also in liver cancer cell line. In conclusion, PMN via elastase induce EMT in vitro, most likely due to the loss of cell-to-cell contact. Because in pancreatic cancers the transition to a mesenchymal phenotype coincides with the PMN infiltrate, a contribution of the inflammatory response to the induction of EMT and—by implication—to tumor progression is possible.