Correction to: Methyl-CpG-binding domain 3 inhibits epithelial-mesenchymal transition in pancreatic cancer cells via TGF-β/Smad signalling.

MicroRNA (miR)-539 has inhibitory effects on certain types of cancer, but its role in pancreatic cancer (PCa) remains unclear. The present study investigated the effects of miR-539 on PCa, and aimed to determine possible therapeutic targets for the treatment of PCa. The expression of miR-539 in PCa tissues, paired normal adjacent tissues and PCa cell lines (CAPAN-2, BxPC3, CFPAC1, SW1990 and PANC1), and human non-cancerous pancreatic cells (hTRET-HPNE) was determined and compared. The effects of upregulation and downregulation of miR-539 on proliferation, apoptosis, cell cycle, invasion, migration and epithelial-mesenchymal transition (EMT) of PCa cells were investigated. Additionally, the target gene of miR-539 was predicted and its effects on PCa cells were further investigated. The results revealed low expression of miR-539 in PCa tissues and cell lines. Additionally, increasing miR-539 expression inhibited the proliferation, migration, invasion and EMT of PCa cells and induced apoptosis by blocking G1 phase of the cell cycle, while reducing miR-539 expression had the opposite results. Furthermore, specificity protein 1 (SP1) was found to be the target gene of miR-539. SP1 promoted the proliferation, migration, invasion and EMT transformation of PCa cells, but these effects were reversed by high expression of miR-539. Additionally, miR-539 suppressed the proliferation, metastasis, invasion and EMT transformation of PCa cells through targeting SP1. Therefore, miR-539 overexpression may contribute toward development of novel therapeutic strategies for PCa in the future.

Hydroxychavicol from Piper betle induces apoptosis, cell cycle arrest, and inhibits epithelial-mesenchymal transition in pancreatic cancer cells

Pancreatic cancer (PC) often correlates with high mortality due to late diagnosis, rapid metastasis, and resistance to chemotherapy. miR-128-3p has been validated as a tumor suppressor in PC. This study explored the functional mechanism of miR-128-3p in epithelial-mesenchymal transition (EMT) of PC cells. Four PC cancer cell lines with different degrees of malignancy and normal pancreatic cells were selected to detect expressions of hsa-miR-128-3p and ZEB1 by RT-qPCR and Western blot. miR-128-3p mimic or si-ZEB1 was delivered into PANC-1 cells and miR-128-3p inhibitor or oe-ZEB1 was delivered into AsPC-1 cells. Expressions of epithelial and mesenchymal markers were analyzed by Western blot and cell fluorescence staining. The binding relationship between miR-128-3p and ZEB1 was examined by bioinformatics analysis and dual-luciferase assay, and verified by RT-qPCR and Western blot. PC cell invasion and migration were assessed by Transwell assays. Generally, hsa-miR-128-3p was poorly-expressed in PC cells. However, it was relatively more expressed in AsPC-1 cells with epithelial phenotypes relative to PANC-1 cells with mesenchymal phenotype, whereas ZEB1 expression showed opposite tendencies. PANC-1 cells transfected with miR-128-3p mimic or si-ZEB1 showed upregulated E-cadherin and downregulated N-cadherin, and transformed from mesenchymal phenotypes to epithelial phenotypes, with decreased invasion and migration, while opposite results occurred in AsPC-1 cells transfected with miR-128-3p inhibitor or oe-ZEB1. miR-128-3p targeted ZEB1. oe-ZEB1 antagonized the inhibition of miR-128-3p mimic on PANC-1 cell EMT, invasion, and migration, while si-ZEB1 reversed the facilitation of miR-128-3p inhibitor in AsPC-1 cells. In conclusion, miR-128-3p inhibited PC cell EMT, invasion, and migration by targeting ZEB1.

Pancreatic stellate cells promote epithelial-mesenchymal transition in pancreatic cancer cells

Objective response rates to standard chemotherapeutic regimens remain low in pancreatic cancer. Subpopulations of cells have been identified in various solid tumors which express stem cell-associated markers and are associated with increased resistance against radiochemotherapy. We investigated the expression of stem cell genes and markers of epithelial-mesenchymal transition in pancreatic cancer cells that survived high concentrations of gemcitabine treatment. Capan-1 and Panc-1 cells were continuously incubated with 1 and 10 µM gemcitabine. Surviving cells were collected after 1, 3 and 6 days. Expression of PDX-1, SHH, CD24, CD44, CD133, EpCAM, CBX7, OCT4, SNAIL, SLUG, TWIST, Ki-67, E-cadherin, β-catenin and vimentin were quantified by qPCR or immunocytochemistry. Migration was assessed by wound‑healing assay. SHH was knocked down using RNA interference. Five primary pancreatic cancer cell lines were used to validate the qPCR results. All investigated genes were upregulated after 6 days of gemcitabine incubation. Highest relative expression levels were observed for OCT4 (13.4-fold), CD24 (47.3-fold) and EpCAM (15.9-fold) in Capan-1 and PDX-1 (13.3‑fold), SHH (24.1-fold), CD44 (17.4-fold), CD133 (20.2-fold) and SLUG (15.2-fold) in Panc-1 cells. Distinct upregulation patterns were observed in the primary cells. Migration was increased in Panc-1 cells and changes in the expression of E-cadherin and β-catenin were typical of epithelial-mesenchymal transition in both cell lines. SHH knockdown reduced IC(50) from 30.1 to 27.6 nM in Capan-1 while it strongly inhibited proli-feration in Panc-1 cells. Cells surviving high-dose gemcitabine treatment express increased levels of stem cell genes, show characteristics associated with epithelial-mesenchymal transition and retain their proliferative capacity.

Pancreatic ductal adenocarcinoma (PDAC), one of the most lethal gastrointestinal cancers, is characterized by the excessive deposition of extracellular matrix (ECM) that has been thought to contribute to the malignant behaviour. However, the detailed mechanism and the contribution of excessive deposition of ECM in PDAC progression remain unclear. A better understanding of the mechanism involved in this process is essential for the design of new effective therapies. In this study, we demonstrated that pancreatic cancer cells exhibited increased proliferation and decreased apoptosis in response to type I collagen. In addition, exposed to type I collagen, PDAC cells lost the expression of E-cadherin and increased expression of mesenchymal markers, including N-cadherin and vimentin, which was correlated with enhanced cell migration and invasiveness. Conversely, the knockdown of β1-integrin abolished the effects induced by type I collagen. Further investigation revealed that type I collagen activates β1-integrin accompanied with significant up-regulation of Gli-1. siRNA specific to Gli-1 reversed the effects of type I collagen on PDAC invasion and epithelial-mesenchymal transition (EMT). These results suggest that there is cross-talk between the β1-integrin signaling pathway and the Hedgehog (HH) pathway in pancreatic cancer and the abnormal activation of the HH pathway plays a key role in the type I collagen-induced effects on pancreatic cancer. Therefore, our findings may have potential significance for the development of new therapeutic strategies to treat this highly aggressive malignancy. Citation Format: Wanxing Duan, Qingyong Ma, Jiguang Ma, Qinhong Xu, Jianjun Lei, Erxi Wu. The activation of β1-integrin by type i collagen coupling with the Hedgehog pathway promotes the epithelial-mesenchymal transition in pancreatic cancer cells. [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 A39.

Pancreatic cancer (PC) is one of the deadliest malignancies worldwide, with a low five-year survival rate of less than 10%. Transforming growth factor β regulator 4 (TBRG4) is differentially expressed in PC tissues, but its specific functions and regulatory role in PC have not been clarified. TBRG4 mRNA expression in PC cells was measured by qRT-PCR. Protein levels of TBRG4, key markers related to the epithelial-mesenchymal transition (EMT) process, and factors related to the TGF-β/smad3 pathway were quantified by western blot. The migratory and invasive abilities of PC cells were evaluated by wound healing and Transwell assays, respectively. Spearman's correlation analysis was performed to analyze the expression correlation between TBRG4 and TGF-β1 (or SMAD3). Xenograft mouse models were established to explore the in vivo role of TBRG4. The mRNA and protein expression of TBRG4 were elevated in PC cells. TBRG4 knockdown repressed PC cell migration, invasion, and the EMT process. Moreover, TBRG4 activated TGF-β/smad3 signaling in PC cells and positively correlated with TGF-β1 (or SMAD3) expression in PC tissues based on bioinformatics analysis. Furthermore, SRI-011381 (an agonist of TGF-β1) counteracted the inhibitory influence of TBRG4 knockdown on PC cellular behaviors, and SB431542 (an inhibitor of the TGF-β type I receptor) treatment countervailed the promoting influence of TBRG4 overexpression on PC cell invasion, migration, and EMT. Results of in vivo assays verified that TBRG4 silencing inhibited tumorigenesis and TGF-β/smad3 signaling. The silencing of TBRG4 inhibits PC cell invasion, migration, EMT, and tumorigenesis by inactivating TGF-β/smad3 signaling.

Recent evidences suggest that the acidic microenvironment might facilitate epithelial mesenchymal transition (EMT) of tumor cells, while the effects of acidity on EMT of pancreatic cancer (PC) remain undefined. The present study demonstrated that acidity suppressed miR-652 expression, which further promoted EMT process by absenting inhibition on the transcriptional factor ZEB1 expression. At first, we found that acidity remarkably enhanced invasion ability of PC cells accompanying with increased mesenchymal and decreased epithelial markers. Meanwhile, miRNAs-microarray showed that miR-652, the potential regulator of ZEB1, was distinctly decreased in acidity-treated PC cells. Furthermore, restoration of miR-652 reversed acidity-induced EMT by inhibiting ZEB1 expression, while miR-652 inhibitor induced EMT in normal PC cells through promoting ZEB1 expression. Nevertheless, knockdown of ZEB1 significantly suppressed acidity-induced EMT in PC cells, but ZEB1 overexpression rescued the EMT which was inhibited by miR-652 overexpression. The in vivo results showed that the tumor growth and liver metastasis were remarkably retarded by both miR-652 overexpression and ZEB1 knockdown. The clinical samples further revealed that miR-652 was decreased in PC tissues and antagonistically correlated with ZEB1 expression, associating with late tumor stage, lymphatic invasion and metastasis. In conclusion, our study indicated a novel acidity/miR-652/ZEB1/EMT axis in the tumorigenesis of PC.

M2-polarized tumor-associated macrophages promoted epithelial–mesenchymal transition in pancreatic cancer cells, partially through TLR4/IL-10 signaling pathway

Amphiregulin (AREG) is a member of the epidermal growth factor (EGF) family and is expressed in a plethora of cancers. The biological roles of AREG in the regulation of the epithelial-mesenchymal transition (EMT) in pancreatic cancer remain unclear. To investigate the expression of epidermal growth factor receptor (EGFR) and AREG in pancreatic cancer cell lines, RT-qPCR, western blot analysis, and ELISA were performed. RNAi and exogenous AREG treatment were used to alter AREG expression. Wound-healing and Transwell assays were performed to evaluate cell migration and invasion abilities. Western blot analysis and immunofluorescence staining were utilized to detect the expression of EMT markers. The protein expression of potential key factors involved in EMT, as well as those of the ERK, AKT, STAT3 and NF-κB pathways, were analysed by western blotting. The role of AREG in tumour growth in vivo was further determined using an orthotopic model of pancreatic cancer. Knockdown of AREG inhibited AsPC-1 cell migration and invasion. AREG knockdown upregulated E-cadherin but downregulated vimentin, Snail and Slug expression in AsPC-1 cells. In addition, AREG stimulation increased cell migration, invasion and EMT in PANC-1 cells, and an NF-κB inhibitor decreased AREG-induced cell migration, invasion and EMT in PANC-1 cells. AREG stimulation increased the nuclear accumulation of NF-κB through the EGFR/ERK signalling pathway to induce EMT. Tumour growth and metastasis were decreased by AREG silencing in an orthotopic model of pancreatic cancer. AREG may play a critical role in cell migration, invasion, and EMT by activating the EGFR/ERK/NF-κB signalling pathway in pancreatic cancer cells.

Methyl-CpG-Binding Protein 2 Drives Furin/TGF-β1/Smad Loop to Promote Epithelial-Mesenchymal Transition in Pancreatic Cancer Cells

Purpose: To investigate the possible mechanism of miR-210 involved in epithelial–mesenchymal transition (EMT) of pancreatic cancer cells under hypoxia. Methods: In this study, we used the following approaches. Hypoxic microenvironment was stimulated in vitro, and the CCK-8 assay was used to analyze cell viability. The MiRNA expression level was measured by qRT-PCR. HOXA9, EMT-related proteins, and NF-κB activities were examined by immunoblotting assay. Dual luciferase reporter assay was used to assess whether HOXA9 was a target of miR-210.Results: Under hypoxia condition, miR-210, HIF-1α and NF-κB were increased, and the HOXA9 was reduced in PANC-1 cells. When miR-210 was overexpressed in normoxic PANC-1 cells, EMT epithelial markers of E-cadherin and β-catenin were down-regulated, and mesenchymal markers of vimentin and N-cadherin were up-regulated to promote cell migration/invasive ability, and the HOXA9 level was decreased. After HOXA9 level decreased, the sensitivity to chemotherapeutic drug of gemcitabine was reduced, NF-κB expression level and cell migration/invasive ability was enhanced. Whereas, miR-210 antagonist into hypoxic PANC-1 cells, which up-regulated E-cadherin, β-catenin level, and down-regulated vimentin and N-cadherin levels to decrease cell migration/invasive ability, and increase the HOXA9. Furthermore, increasing HOXA9 level decreased NF-κB expression level and cell migration/invasive ability, enhanced the sensitivity to gemcitabine. At last, miRDB and TargetScan predicted that HOXA9 was a target of miR-210, and dual luciferase reporter assay verified this hypothesis.Conclusion: MiR-210 inhibited the expression of HOXA9 to activate the NF-κB signaling pathway and mediated the occurrence of EMT of pancreatic cancer cells induced by HIF-1α under hypoxia.

To investigate the effects of K-ras siRNA on pancreatic cancer cells and the expression levels of GLI1, E-cadherin and vimentin in pancreatic cancer cells transfected with K-ras siRNA. Ppancreatic cancer cells PANC-1 were transfected with K-ras siRNA. Growth inhibition ratio of the cells were measured by MTT assay, apoptosis was detected by flow cytometery, expression level of GLI1, E-cadherin and vimentin were detected by Western blot. The expression of K-ras protein was efficiently inhibited by K-ras siRNA in PANC-1 cells. The growth inhibition rates of the cells were significantly different to the control groups. Apoptosis rates were significantly different with that of control group. The expression of GLI1 was significantly down-regulated, E-cadherin was up-regulated, while vimentin was also down-regulated in K-ras siRNA transfected cells compared with that of control groups. Inhibiting K-ras signaling by K-ras siRNA can inhibit proliferation and induce apoptosis of pancreatic cancer cells, down-regulate GLI1's and vimentin's expression, and up-regulate E-cadherin's expression. Inhibiting K-ras signaling by K-ras siRNA may reduce epithelial to mesenchymal transition of pancreatic cancer cell PANC-1.

Gemcitabine is a broad-spectrum antimetabolite and a deoxycytidine analog recognized as a standard therapy alone or in combination with other antineoplastic agents in the therapy of pancreas cancer. Drug resistance following gemcitabine treatment is a common phenomenon; therefore, combinational therapy models are usually preferred. Pancreatic ductal adenocarcinoma, or pancreas cancer, is the fourth leading cause of cancer-related deaths worldwide. With the increasing incidence of pancreatic cancer every year, the mortality rate is also rising significantly because of late diagnosis, and limited chemotherapy options. Adjuvant chemotherapy after surgical resection is the typical option for the treatment of early pancreatic cancer. Mostly, 5-fluorouracil/leucovorin with irinotecan and oxaliplatin (FOLFIRINOX) and gemcitabine/nab-paclitaxel is used for the prognosis of advanced pancreatic cancer; however, chemoresistance usually occurs limiting the effectiveness of the chemotherapy. Therefore, most of the studies are focused on gemcitabine combination with other drugs to overcome the situation.As an apoptotic agent and a member of brassinosteroids, epibrassinolide (EBR) induces endoplasmic reticulum (ER) stress-dependent cell death in different cancer cells, as shown by our group. In this study, we aimed to enhance the gemcitabine apoptotic effect by EBR combined treatment in pancreatic cancer cells. EBR treatment reduced cell viability and inhibited cell proliferation in PANC-1, MIA PaCa-2, and AsPC-1 cells. Each pancreatic cancer cell gave different responses to the EBR treatment because of different aggressiveness. However, EBR induced apoptosis through increasing ROS generation, which was associated with ER stress in PANC-1 and MIA PaCa-2 cells. Gemcitabine alone reduced the cell viability of each pancreatic cancer cell line; however, combination with EBR led to further induction of apoptotic cell death in each pancreatic cancer cell line. In addition, combined treatment of gemcitabine and EBR further decreased N-cadherin and vimentin expressions, suggesting that epithelial-mesenchymal transition of pancreatic cells is reduced. In conclusion, EBR had therapeutic potential to avoid the gemcitabine-induced side effects during the treatment of pancreatic cancer.

Nutrient Scavenging From Muscle Cells: A Survival Strategy of Pancreatic Cancer Cells Ends in Cachexia