Epithelial-to-mesenchymal Transition In Pancreatic Cancer Cells Research Articles

GK921, a transglutaminase inhibitor, strengthens the antitumor effect of cisplatin on pancreatic cancer cells by inhibiting epithelial-to-mesenchymal transition

Pancreatic adenocarcinoma (PAAD), a common digestive malignant tumor, presents high mortality rates and limited treatment methods. Currently, chemotherapy remains the main therapy method for patients with PAAD. As a classical chemotherapy drug, cisplatin (DDP) is limited by dose-related toxicity in patients with PAAD. In this study, we demonstrated that TGM2 may be a treatment and prognosis marker in pancreatic cancer patients. Co-treatment of low dose of DDP and GK921, a transglutaminase (TGM2) inhibitor, is capable of synergistically inhibiting the PAAD cell viability and proliferation in vitro and in vivo. Based on in vitro study, GK921 inhibited the epithelial-to-mesenchymal transition (EMT) induced by TGM2 as well as aggravated cell cycle arrest and apoptosis resulted from DDP, making pancreatic cancer cells more sensible to DDP. Our results showed that GK921 increased the protein levels regarding E-cadherin as well as decreased the protein level regarding Snail2, N-cadherin, which indicated that GK921 inhibited EMT in pancreatic cancer cells. Snail2 overexpression inhibited GK921/DDP-induced cell apoptosis, as well as mitigated the GK921/DDP-caused cell death and the EMT inhibition. In vivo studies also found GK921/DDP combination can further inhibit the growth of PAAD without significantly side effects. To sum up, we showed that GK921 increased PAAD cells sensitivity to DDP via inhibiting EMT. As revealed, DDP/GK921 co-treatment could promisingly serve for treating PAAD patients.

Circ_0018909 knockdown inhibits the development of pancreatic cancer via the miR-545-3p/FASN axis and reduces macrophage polarization to M2.

Multiple circular RNAs (circRNAs) were proven to regulate the development of pancreatic cancer. However, the action of circ_0018909 in pancreatic cancer was still unclear. The expression of circ_0018909, microRNA-545-3p (miR-545-3p), and fatty acid synthase (FASN) was measured using quantitative reverse-transcriptase PCR (qRT-PCR). Cell growth, cell cycle arrest, apoptotic cells, metastasis, and epithelial to mesenchymal transition (EMT) were determined using EdU assay, flow cytometry, wound-healing assay, transwell invasion, and western blotting, respectively. The expression of the macrophage markers, including CD80, MCP-1, iNOS, and IL-6 (M1 markers), as well as CD206 and CD163 (M2 markers), was analyzed using qRT-PCR. Circ_0018909 knockdown dramatically depressed cell growth, migration, invasion, EMT, and elevated the number of apoptotic cells in pancreatic cancer cells, and repressed tumor growth in mice. Moreover, we proved that the absence of miR-545-3p rescued the action of circ_0018909 downregulation on cell growth, metastasis, apoptosis, and EMT in pancreatic cancer cells. MiR-545-3p bound to FASNand FASN overexpression hindered the impacts of miR-545-3p on the progression of pancreatic cancer. Besides this, our data demonstrated that circ_0018909 induced polarization from M0 macrophages to M2 macrophages. Circ_0018909 knockdown retarded the development of pancreatic cancer by modulating miR-545-3p to regulate FASN expression.

TGFβ Drives Metabolic Perturbations during Epithelial Mesenchymal Transition in Pancreatic Cancer: TGFβ Induced EMT in PDAC.

Simple SummaryPancreatic cancer is an aggressive disease with most patients diagnosed at late stages resulting in poor outcomes. While it is known that pancreatic tumor cells undergo epithelial to mesenchymal transition, the metabolic alterations accompanying that transition are not characterized. This study leveraged a metabolomics approach to understand the small molecule and biochemical perturbations that can be targeted for designing strategies for improving outcomes in pancreatic cancer.Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy wherein a majority of patients present metastatic disease at diagnosis. Although the role of epithelial to mesenchymal transition (EMT), mediated by transforming growth factor beta (TGFβ), in imparting an aggressive phenotype to PDAC is well documented, the underlying biochemical pathway perturbations driving this behaviour have not been elucidated. We used high-resolution mass spectrometry (HRMS) based molecular phenotyping approach in order to delineate metabolic changes concomitant to TGFβ-induced EMT in pancreatic cancer cells. Strikingly, we observed robust changes in amino acid and energy metabolism that may contribute to tumor invasion and metastasis. Somewhat unexpectedly, TGFβ treatment resulted in an increase in intracellular levels of retinoic acid (RA) that in turn resulted in increased levels of extracellular matrix (ECM) proteins including fibronectin (FN) and collagen (COL1). These findings were further validated in plasma samples obtained from patients with resectable pancreatic cancer. Taken together, these observations provide novel insights into small molecule dysregulation that triggers a molecular cascade resulting in increased EMT-like changes in pancreatic cancer cells, a paradigm that can be potentially targeted for better clinical outcomes.

An RNA-Binding Protein, Hu-antigen R, in Pancreatic Cancer Epithelial to Mesenchymal Transition, Metastasis, and Cancer Stem Cells.

Pancreatic cancer has poor prognosis and treatment outcomes due to its highly metastatic nature and resistance to current treatments. The RNA-binding protein (RBP) Hu-antigen R (HuR) is a central player in posttranscriptional regulation of cancer-related gene expression, and contributes to tumorigenesis, tumor growth, metastasis, and drug resistance. HuR has been suggested to regulate pancreatic cancer epithelial-to-mesenchymal transition (EMT), but the mechanism was not well understood. Here, we further elucidated the role HuR plays in pancreatic cancer cell EMT, and developed a novel inhibitor specifically interrupting HuR-RNA binding. The data showed that HuR binds to the 3'-UTR of the mRNA of the transcription factor Snail, resulting in stabilization of Snail mRNA and enhanced Snail protein expression, thus promoted EMT, metastasis, and formation of stem-like cancer cells (CSC) in pancreatic cancer cells. siRNA silencing or CRISPR/Cas9 gene deletion of HuR inhibited pancreatic cancer cell EMT, migration, invasion, and inhibited CSCs. HuR knockout cells had dampened tumorigenicity in immunocompromised mice. A novel compound KH-3 interrupted HuR-RNA binding, and KH-3 inhibited pancreatic cancer cell viability, EMT, migration/invasion in vitro KH-3 showed HuR-dependent activity and inhibited HuR-positive tumor growth and metastasis in vivo.

FAM172A inhibits EMT in pancreatic cancer via ERK-MAPK signaling.

ABSTRACTFAM172A, as a newly discovered gene, is little known in cancer development, especially in pancreatic cancer (PC). We investigated the potential role and molecular mechanism of FAM172A in epithelial to mesenchymal transition (EMT) in both human clinical samples and PC cells. FAM172A was downregulated in human PC tissues compared with that in non-cancerous pancreas cells by immunohistochemistry and qRT-PCR. FAM172A expression was negatively associated with tumor size (P=0.015), T stage (P=0.006), lymph node metastasis (P=0.028) and the worst prognosis of PC patients (P=0.004). Meanwhile, a positive relationship between FAM172A and E-cadherin (E-cad) (r=0.381, P=0.002) was observed in clinical samples, which contributed to the better prognosis of PC patients (P=0.014). FAM172A silencing induced EMT in both AsPC-1 and BxPC-3 cells, including inducing the increase of Vimentin, MMP9 and pERK and the decrease of E-cad and β-catenin expression, stimulating EMT-like cell morphology and enhancing cell invasion and migration in PC cells. However, MEK1 inhibitor PD98059 reversed FAM172A silencing-enhanced EMT in PC cells. We conclude that FAM172A inhibits EMT of PC cells via ERK-MAPK signaling.

Abstract A60: The hMENA Splicing Program: An important regulator of TGFβ1-driven EMT and invasiveness in pancreatic cancer

Abstract Background: The pancreatic ductal adenocarcinoma tumor microenvironment plays an important role in promoting the epithelial to mesenchymal transition (EMT), an early event in pancreatic cancer, involved in cancer invasiveness and in tumor progression. Among the stromal components the cancer-associated fibroblasts (CAFs) are responsible for the peculiar pancreatic tumor microenvironment and are known to be linked to the induction of EMT. The EMT process requires a dynamic remodeling of the actin cytoskeleton and we have suggested that the splicing program of hMENA, an actin regulator, play a role in EMT. Two alternatively expressed isoforms, hMENA11a and hMENAΔv6, with opposite functions in invasiveness have been described in breast cancer (Di Modugno et al PNAS 2012). hMENA expression has not been detected in normal pancreatic ducts, whereas expressed in the human pancreatic ductal adenocarcinoma (PDAC) samples, but no data are available on hMENA alternative isoform expression in this neoplasia. The aim of this study is to investigate whether TGFβ1-mediated EMT in pancreatic cancer cells is affected by hMENA overexpression and splicing and how CAFs affect this process in cancer cell lines and in human tissues. Methods: hMENA isoform expression was evaluated in PDAC tissues by immunohistochemistry using isoform specific antibodies. hMENA isoforms and EMT markers expression were characterized in human PDAC cell lines, TGFβ1-treated or untreated, by qRT-PCR and WB analysis. The effects of either hMENA isoform specific knockdown or overexpression in the TGFβ1-induced EMT were also evaluated. Pancreatic CAFs were isolated from human tissues of resected PDAC patients. The effect of the conditioned medium of cultured CAFs was evaluated on hMENA expression. In parallel, the role of CAF-cancer cell interaction on the expression of the different hMENA isoforms was analysed using a co-culture system. Results: Freshly explanted CAFs expressed the “mesenchymal” hMENAΔv6, and not hMENA11a and secreted paracrine factors involved in the induction of hMENA isoforms in tumor cells. In a panel of pancreatic cancer cell lines, hMENA11a expression correlated with an epithelial phenotype, while hMENAΔv6 expression was correlated with a mesenchymal phenotype. Interestingly, the expression of the invasive hMENAΔv6 isoform is specifically up-regulated by TGFβ1 treatment. hMENA isoform expression levels influenced molecular changes induced by TGFβ1. Thus, the hMENA11a specific silencing led to E-cadherin down-regulation that is more evident in TGFβ1 treated cells. On the contrary, hMENA11a overexpression led to a reduction of vimentin expression and to E-cadherin up-regulation. Knockdown of the endogenous hMENA/hMENAΔv6 isoform expression prevented the activation of TGFβ1 signaling and up-regulation of mesenchymal markers. In addition, hMENA/hMENAΔv6 isoform depletion impaired the TGFβ1-induced invasiveness, migration and production of MMPs. IHC analysis of PDAC tissues revealed that the epithelial hMENA11a is rarely expressed in primary pancreatic tumour, while high levels of hMENA and hMENAΔv6 isoforms were found in 75% of primary tumours analysed. Conclusions: This data suggests that the lack of the epithelial hMENA11a isoform is an early event in pancreatic cancer, provides new insights into the role of hMENA splicing in TGFβ1-mediated EMT and highlights hMENA splicing program as an attractive pathway for the development of new therapies in PDAC. Citation Format: Roberta Melchionna, Pierluigi Iapicca, Francesca Di Modugno, Paola Trono, Novella Gualtieri, Maria Grazia Diodoro, Marcella Mottolese, Gian Luca Grazi, Matteo Fassan, Aldo Scarpa, Mina J. Bissell, Paola Nisticò. The hMENA Splicing Program: An important regulator of TGFβ1-driven EMT and invasiveness in pancreatic cancer. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Innovations in Research and Treatment; May 18-21, 2014; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2015;75(13 Suppl):Abstract nr A60.

Vitamin D receptor signaling and pancreatic cancer cell EMT.

Pancreatic ductal adenocarcinoma (PDAC) still remains one of the most fatal human malignant tumors. Long-term survival rate is still extremely pathetic even for patients who receive surgery. Epithelial-to-mesenchymal transition (EMT), which is a physiologic process of morphological as well as genetic changes in carcinoma cells, plays a vital role in aggressiveness of PDAC. Meanwhile EMT is also the reason why pancreatic cancer cells achieve such huge metastatic potentials. Many tumor microenvironmental factors such as cytokines, growth factors, as well as chemotherapeutic agents may induce EMT. Our study provides evidence regarding effects of EMT on pancreatic cancer progression, focusing on the correlation between EMT and other pathways which are crucial to tumor progression, especially vitamin D receptor signaling pathway. Research on signal pathways resulting in EMT inactivation during these disease processes may offer innovative ideas on plasticity of cellular phenotypes as well as possible therapeutic interventions.

Alisertib induces cell cycle arrest and autophagy and suppresses epithelial-to-mesenchymal transition involving PI3K/Akt/mTOR and sirtuin 1-mediated signaling pathways in human pancreatic cancer cells.

Pancreatic cancer is the most aggressive cancer worldwide with poor response to current therapeutics. Alisertib (ALS), a potent and selective Aurora kinase A inhibitor, exhibits potent anticancer effects in preclinical and clinical studies; however, the effect and underlying mechanism of ALS in the pancreatic cancer treatment remain elusive. This study aimed to examine the effects of ALS on cell growth, autophagy, and epithelial-to-mesenchymal transition (EMT) and to delineate the possible molecular mechanisms in human pancreatic cancer PANC-1 and BxPC-3 cells. The results showed that ALS exerted potent cell growth inhibitory, pro-autophagic, and EMT-suppressing effects in PANC-1 and BxPC-3 cells. ALS remarkably arrested PANC-1 and BxPC-3 cells in G2/M phase via regulating the expression of cyclin-dependent kinases 1 and 2, cyclin B1, cyclin D1, p21 Waf1/Cip1, p27 Kip1, and p53. ALS concentration-dependently induced autophagy in PANC-1 and BxPC-3 cells, which may be attributed to the inhibition of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR), p38 mitogen-activated protein kinase (p38 MAPK), and extracellular signal-regulated kinases 1 and 2 (Erk1/2) but activation of 5′-AMP-dependent kinase signaling pathways. ALS significantly inhibited EMT in PANC-1 and BxPC-3 cells with an increase in the expression of E-cadherin and a decrease in N-cadherin. In addition, ALS suppressed the expression of sirtuin 1 (Sirt1) and pre-B cell colony-enhancing factor/visfatin in both cell lines with a rise in the level of acetylated p53. These findings show that ALS induces cell cycle arrest and promotes autophagic cell death but inhibits EMT in pancreatic cancer cells with the involvement of PI3K/Akt/mTOR, p38 MAPK, Erk1/2, and Sirt1-mediated signaling pathways. Taken together, ALS may represent a promising anticancer drug for pancreatic cancer treatment. More studies are warranted to investigate other molecular targets and mechanisms and verify the efficacy and safety of ALS in the treatment of pancreatic cancer.

Resveratrol Inhibits the Epithelial-Mesenchymal Transition of Pancreatic Cancer Cells Via Suppression of the PI-3K/Akt/NF-κB Pathway

Resveratrol (trans-3,4',5-trihydroxystilbene), a natural polyphenolic compound detected in grapes, berries, and peanuts, possesses a wide spectrum of pharmacological properties, including anti-tumor metastasis activities. However, the underlying mechanisms through which resveratrol inhibits the metastasis of pancreatic cancer are still not fully elucidated. As epithelial-to-mesenchymal transition (EMT) is a key player for metastasis in tumor, the aim of this study is to determine whether resveratrol affects EMT in pancreatic cancer cells and the related mechanism. The results showed that resveratrol not only inhibited cell proliferation, migration, and invasion in a dose-dependent manner, but also mediated the expression of EMT-related genes (E-cadherin, N-cadherin, vimentin, MMP-2, and MMP-9) which are important for cancer cellular motility, invasiveness and metastasis during tumorigenesis. In addition, the levels of phospho-Akt and phospho- NF-κB in BxPC-3 and Panc-1 cells were reduced by both resveratrol and LY294002 (a PI3-K inhibitor). Furthermore, transforming growth factor-β (TGF-β)-induced alterations in cell morphology that are characteristic of EMT as well as increased cell invasive ability could also be reversed by resveratrol. Taken together, these data indicate that resveratrol suppresses pancreatic cancer migration and invasion through the inhibition of the PI-3K/Akt/NF-κB signaling pathway. This study suggests that resveratrol may be a potential anticancer agent for pancreatic cancer.

Cancer Stem Cells, EMT, and Developmental Pathway Activation in Pancreatic Tumors.

Pancreatic cancer is a disease with remarkably poor patient survival rates. The frequent presence of metastases and profound chemoresistance pose a severe problem for the treatment of these tumors. Moreover, cross-talk between the tumor and the local micro-environment contributes to tumorigenicity, metastasis and chemoresistance. Compared to bulk tumor cells, cancer stem cells (CSC) have reduced sensitivity to chemotherapy. CSC are tumor cells with stem-like features that possess the ability to self-renew, but can also give rise to more differentiated progeny. CSC can be identified based on increased in vitro spheroid- or colony formation, enhanced in vivo tumor initiating potential, or expression of cell surface markers. Since CSC are thought to be required for the maintenance of a tumor cell population, these cells could possibly serve as a therapeutic target. There appears to be a causal relationship between CSC and epithelial-to-mesenchymal transition (EMT) in pancreatic tumors. The occurrence of EMT in pancreatic cancer cells is often accompanied by re-activation of developmental pathways, such as the Hedgehog, WNT, NOTCH, and Nodal/Activin pathways. Therapeutics based on CSC markers, EMT, developmental pathways, or tumor micro-environment could potentially be used to target pancreatic CSC. This may lead to a reduction of tumor growth, metastatic events, and chemoresistance in pancreatic cancer.

145P - ZEB1 and ZEB2 Mediate Pancreatic Fibroblast Induced Epithelial-To Mesenchymal Transition (EMT) in Pancreatic Cancer

ABSTRACT EMT renders neoplastic cancer cells the ability to migrate and to invade distant organs. The hallmark of EMT is the loss of E-cadherin, which is a prerequisite for epithelial tumor cell invasion. In pancreatic cancer, loss of tumor E-cadherin is an independent predictor of poor outcome.AIMS: To analyze the effect of pancreatic fibroblasts (PF) on inducing EMT in pancreatic cancer cells and to identify the transcription factors (Snail, Slug, ZEB1, ZEB2) that mediate EMT process. Methods Human PFs were isolated from human pancreatic specimens obtained from chronic pancreatitis and from unaffected margins of pancreatic adenocarcinoma and serous cistoadenoma. PF were cultured until complete cellular activation, as assessed by expression of a-smooth muscle actin, vimentin and fibronectin. Human pancreatic cancer cells Panc-1 were exposed to PF conditioned medium (PF-CM) and EMT analyzed by cell morphology, migration, and E-cadherin expression (quantitative RT-PCR and immunoblot). Gene expression of Snail, Slug, ZEB1, and ZEB2 was analyzed by quantitative RT-PCR, and their activity modulated by siRNA. Results Conditioned media from all types of activated PFs induced EMT changes in Panc-1 cells, as shown by 1) morphological transition from cobblestone shaped to fibroblast-like cells, 2) stimulation of cell migration, and 3) E-cadherin down–regulation; mRNA expression of Snail transiently increased at 30 min after exposure to PF returning to basal levels afterwards; mRNA levels of ZEB1 were not up-regulated upon exposure to PF-CM. However, ZEB1 protein greatly accumulated after 48h incubation with PF-CM, suggesting that PF prevent ZEB1 degradation in Panc-1 cells. Combined RNA downregulation of ZEB1 and ZEB2, but not of Snail and/or Slug, suppressed E-cadherin repression induced by PF. Conclusion Activated PFs promote the invasive phenotype of pancreatic cancer cells through ZEB1 and ZEB2 activation. Disclosure All authors have declared no conflicts of interest.

Effect of zeb1 and zeb2 on pancreatic fibrobast-induced epithelial-to-mesenchymal transition (EMT) in pancreatic cancer.

e21035 Background: EMT renders neoplastic cancer cells the ability to migrate and to invade distant organs. The hallmark of EMT is the loss of E-cadherin, which is a prerequisite for epithelial tumor cell invasion. In pancreatic cancer, loss of tumor E-cadherin is an independent predictor of poor outcome. Aims: To analyze the effect of pancreatic fibroblasts (PF) on inducing EMT in pancreatic cancer cells and to identify the transcription factors (Snail, Slug, ZEB1, ZEB2) that mediate EMT process. Methods: Human PFs were isolated from human pancreatic specimens obtained from chronic pancreatitis and from unaffected margins of pancreatic adenocarcinoma and serous cistoadenoma. PF were cultured until complete cellular activation, as assessed by expression of α-smooth muscle actin, vimentin and fibronectin. Human pancreatic cancer cells Panc-1 were exposed to PF conditioned medium (PF-CM) and EMT analyzed by cell morphology, migration, and E-cadherin expression (quantitative RT-PCR and immunoblot). Gene expression of Snail, Slug, ZEB1, and ZEB2 was analyzed by quantitative RT-PCR, and their activity modulated by siRNA Results: Conditioned media from all types of activated PFs induced EMT changes in Panc-1 cells, as shown by 1) morphological transition from cobblestone shaped to fibroblast-like cells, 2) stimulation of cell migration, and 3) E-cadherin down–regulation; mRNA expression of Snail transiently increased at 30 min after exposure to PF returning to basal levels afterwards; mRNA levels of ZEB1 were not up-regulated upon exposure to PF-CM. However, ZEB1 protein greatly accumulated after 48h incubation with PF-CM, suggesting that PF prevent ZEB1 degradation in Panc-1 cells. Combined RNA downregulation of ZEB1 and ZEB2, but not of Snail and/or Slug, suppressed E-cadherin repression induced by PF. Conclusions: Activated PFs promote the invasive phenotype of pancreatic cancer cells through ZEB1 and ZEB2 activation.

JDP2 inhibits the epithelial-to-mesenchymal transition in pancreatic cancer BxPC3 cells

Pancreatic carcinoma is one of the most malignant and aggressive cancers. Increased motility and invasiveness of pancreatic cancer cells are believed to be associated with epithelial-to-mesenchymal transition (EMT). However, the molecular basis of EMT in pancreatic cancer cells is poorly understood. In this study, we examined the relationship between Jun dimerization protein 2 (JDP2), which is an AP-1 inhibitor, and EMT in human pancreatic carcinoma cells. We demonstrated that transforming growth factor-β1 (TGF-β1) promoted epidermal growth factor (EGF)-induced EMT in co-treated human pancreatic BxPC3 cells and that JDP2 overexpression reversed the EMT that was induced by co-treatment with TGF-β1 and EGF. These results suggest that EGF plays a principal role in EMT through its association with TGF-β1 in human pancreatic BxPC3 cells and that JDP2 may be a molecular target for pancreatic carcinoma intervention.

Abstract 2593: HDAC inhibition reverses EMT through modulation of ZEB1

Abstract Histone deacetylase (HDAC) inhibition is known to inhibit the Epithelial-to-Mesenchymal Transition (EMT) in various cancer models by suppressing the acetylation of histone H3 and H4 of E-Cadherin promoter. However, the exact mechanism of EMT inhibition by HDAC inhibition is not known. In the present study, using various HDAC inhibitors such as Vorinostat (SAHA), Tricostatin A (TSA) and Panobinostat (LBH-589), we explored the molecular mechanisms of EMT inhibition in pancreatic tumor cells in vitro and in vivo. The expression of epithelial markers such as E-Cadherin and cytokeratin 18 were significantly up regulated inPanC-1, BxPC-3 and AsPC-1 cells treated with HDAC inhibitors, whereas the expression of mesenchymal marker vimentin decreased. Morphology of the cells also changed indicating that HDAC inhibitors suppressed EMT in pancreatic cancer cells. To determine whether HDAC inhibition correlates with the down-regulation of key transcriptional suppressors of E-Cadherin such as SNAIL1, SNAIL2, TWIST and ZEB, cells were treated with panobinostat. To our surprise, SNAIL1 expression was drastically increased, whereas expression of SNAIL2, TWIST and ZEB were decreased by HDAC inhibition in all the cell lines. Since, it has been previously shown that HDAC activity is required to suppress E-Cadherin expression by its repressors, we wanted to see whether SNAIL1 also requires HDAC activity to repress E-Cadherin expression in our model. HDAC1/2 was co-immunoprecipitated with SNAIL1. Our results revealed that this interaction was more pronounced in control cells as compared to HDAC inhibitors treated cells. These results suggest that although SNAIL1 expression was significantly increased by HDAC inhibition, it remained ineffective in E-Cadherin promoter. To evaluate other repressors, PanC-1 cells were transfected with SNAIL2 and ZEB1 and treated with HDAC inhibitors. Interestingly, our results show that SNAIL2 overexpression was unable to abrogate increase in E-Cadherin by HDAC inhibition. However, ZEB1 overexpression completely blocked the induction of HDAC-mediated E-Cadherin expression. To validate in vitro observations in an in vivo model, BxPC-3 cells were subcutaneously implanted in athymic nude mice. When the tumors reached about 70mm3, 20mg/Kg panobinostat was administered intraperitonealy three times a week while control group received vehicle alone. After 4 weeks of treatment, the growth of pancreatic tumors was significantly suppressed in panabinostat treated mice. Moreover, the tumors from panabinostat treated mice showed an increase in E-Cadherin and decrease in ZEB expression. The expression of other E-Cadherin repressors SNAIL1 and SNAIL2 were also down regulated. In conclusion, our in vitro and in vivo results clearly show that increase in E-Cadherin by HDAC inhibition was due to the down regulation of ZEB1. [Supported in part by R01 grants CA129038 and CA106953 (to S.K.S) awarded by the National Cancer Institute]. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2593. doi:1538-7445.AM2012-2593

The Role of EMT in Pancreatic Cancer Progression

The Role of EMT in Pancreatic Cancer Progression

Nuclear Factor-κB–Dependent Epithelial to Mesenchymal Transition Induced by HIF-1α Activation in Pancreatic Cancer Cells under Hypoxic Conditions

BackgroundEpithelial to mesenchymal transition (EMT) induced by hypoxia is one of the critical causes of treatment failure in different types of human cancers. NF-κB is closely involved in the progression of EMT. Compared with HIF-1α, the correlation between NF-κB and EMT during hypoxia has been less studied, and although the phenomenon was observed in the past, the molecular mechanisms involved remained unclear.Methodology/Principal FindingsHere, we report that hypoxia or overexpression of hypoxia-inducible factor-1α (HIF-1α) promotes EMT in pancreatic cancer cells. On molecular or pharmacologic inhibition of NF-κB, hypoxic cells regained expression of E-cadherin, lost expression of N-cadherin, and attenuated their highly invasive and drug-resistant phenotype. Introducing a pcDNA3.0/HIF-1α into pancreatic cancer cells under normoxic conditions heightened NF-κB activity, phenocopying EMT effects produced by hypoxia. Conversely, inhibiting the heightened NF-κB activity in this setting attenuated the EMT phenotype.Conclusions/SignificanceThese results suggest that hypoxia or overexpression of HIF-1α induces the EMT that is largely dependent on NF-κB in pancreatic cancer cells.