Blockade of dual-specificity phosphatase 28 decreases chemo-resistance and migration in human pancreatic cancer cells

Cellular and molecular features related to exceptional therapy response and extreme long-term survival in glioblastoma

Glioblastoma Multiforme (GBM) remains the most common malignant primary brain tumor with a dismal prognosis that rarely exceeds beyond 2 years despite extensive therapy, which consists of maximal safe surgical resection, radiotherapy, and/or chemotherapy. Recently, it has become clear that GBM is not one homogeneous entity and that both intra-and intertumoral heterogeneity contributes significantly to differences in tumoral behavior which may consequently be responsible for differences in survival. Strikingly and in spite of its dismal prognosis, small fractions of GBM patients seem to display extremely long survival, defined as surviving over 10 years after diagnosis, compared to the large majority of patients. Although the underlying mechanisms for this peculiarity remain largely unknown, emerging data suggest that still poorly characterized both cellular and molecular factors of the tumor microenvironment and their interplay probably play an important role. We hereby give an extensive overview of what is yet known about these cellular and molecular features shaping extreme long survival in GBM.

DUSP3 regulates phosphorylation-mediated degradation of occludin and is required for maintaining epithelial tight junction

Background

Tight junctions (TJ) are multi-protein complexes that hold epithelial cells together and form structural and functional barriers for maintaining proper biological activities. Dual specificity phosphatase 3 (DUSP3), a suppressor of multiple protein tyrosine (Tyr) kinases, is decreased in lung cancer tissues. Here we demonstrated the role of DUSP3 in regulation of epithelial TJ.

Methods

Barrier functions of TJ were examined in wild-type or DUSP3-deficient lung epithelial cells. Animal and clinical data were analyzed for the association between DUSP3 deficiency and lung cancer progression. Proximity ligation assay, immunoblotting, and phosphatase assay were performed to study the effect of DUSP3 on the TJ protein occludin (OCLN). Mutations of Tyr residues on OCLN showed the role of Tyr phosphorylation in regulating OCLN.

Results

Compared to those of the DUSP3-expressing cells, we found the expression and distribution of ZO-1, a TJ-anchoring molecule, were abnormal in DUSP3-deficient cells. OCLN had an increased phosphorylation level in DUSP3-deficient cells. We identified that OCLN is a direct substrate of DUSP3. DUSP3 regulated OCLN ubiquitination and degradation through decreasing OCLN tyrosine phosphorylation directly or through suppressing focal adhesion kinase, the OCLN kinase.

Conclusion

Our study revealed that DUSP3 is an important TJ regulatory protein and its decrease may be involved in progression of epithelial cancers.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12929-022-00826-x.

Soluble TGFBI aggravates the malignancy of cholangiocarcinoma through activation of the ITGB1 dependent PPARγ signalling pathway

BACKGROUND

Cholangiocarcinoma is a devastating cancer with a poor prognosis. Previous reports have presented conflicting results on the role of transforming growth factor-β-induced protein (TGFBI) in malignant cancers. Currently, our understanding of the role of TGFBI in cholangiocarcinoma is ambiguous. The aim of the present study was to investigate the role of TGFBI in human cholangiocarcinoma.

METHODS

Iterative patient partitioning (IPP) scoring and consecutive elimination methods were used to select prognostic biomarkers. mRNA and protein expression levels were determined using Gene Expression Omnibus (GEO), Western blot and ELISA analyses. Biological activities of selected biomarkers were examined using both in vitro and in vivo assays. Prognostic values were assessed using Kaplan-Meier and Liptak's z score analyses.

RESULTS

TGFBI was selected as a candidate cholangiocarcinoma biomarker. GEO database analysis revealed significantly higher TGFBI mRNA expression levels in cholangiocarcinoma tissues compared to matched normal tissues. TGFBI protein was specifically detected in a soluble form in vitro and in vivo. TGFBI silencing evoked significant anti-cancer effects in vitro. Soluble TGFBI treatment aggravated the malignancy of cholangiocarcinoma cells both in vitro and in vivo through activation of the integrin beta-1 (ITGB1) dependent PPARγ signalling pathway. High TGFBI expression was associated with a poor prognosis in patients with cholangiocarcinoma.

CONCLUSIONS

Our data suggest that TGFBI may serve as a promising prognostic biomarker and therapeutic target for cholangiocarcinoma.

The emerging roles of dual-specificity phosphatases and their specific characteristics in human cancer

Reversible phosphorylation of proteins, controlled by kinases and phosphatases, is involved in various cellular processes. Dual-specificity phosphatases (DUSPs) can dephosphorylate phosphorylated serine, threonine and tyrosine residues. This family consists of 61 members, 44 of which have been identified in human, and these 44 members are classified into six subgroups, the phosphatase and tensin homolog (PTEN) protein phosphatases (PTENs), mitogen-activated protein kinase phosphatases (MKPs), atypical DUSPs, cell division cycle 14 (CDC14) phosphatases (CDC14s), slingshot protein phosphatases (SSHs), and phosphatases of the regenerating liver (PRLs). Growing evidence has revealed dysregulation of DUSPs as one of the common phenomenons and highlighted their key roles in human cancers. Furthermore, their differential expression may be a potential biomarker for tumor prognosis. Despite this, there are still many unstudied members of DUSPs need to further explore their precise roles and mechanism in cancers. Most importantly, the systematic review is very limited on the functional/mechanistic characteristics and clinical application of DUSPs at present. In this review, the structures, functions and underlying mechanisms of DUSPs are systematically reviewed, and the molecular and functional characteristics of DUSPs in different tumor types according to the current researches are summarized. In addition, the potential roles of the unstudied members and the possible different mechanisms of DUSPs in cancer are discussed and classified based on homology alignment and structural domain analyses. Moreover, the specific characteristics of their expression and prognosis are further determined in more than 30 types of human cancers by using the online databases. Finally, their potential application in precise diagnosis, prognosis and treatment of different types of cancers, and the main possible problems for the clinical application at present are prospected.

Association of Jagged1 expression with malignancy and prognosis in human pancreatic cancer

PURPOSE

Pancreatic cancer is one of the most aggressive cancers. Preclinical and clinical data indicate that Notch 1 ligand jagged1 (JAG1) plays a pro-oncogenic role in several malignant cancers. As yet, however, the role of JAG1 in pancreatic cancer is poorly understood. The objective of the present study was to investigate JAG1 as a therapeutic target in human pancreatic cancer.

METHODS

Expression levels of Notch signaling molecules were assessed using GEO datasets and Western blot analysis, respectively. Anti-tumor effects following JAG1 silencing were evaluated using in vitro and in vivo assays. Prognostic implications were assessed using GEO datasets.

RESULTS

Using GEO datasets and Western blot analysis we detected significantly higher JAG1 mRNA and protein expression levels in pancreatic cancer compared to normal pancreatic tissues. JAG1 silencing significantly restrained the growth, migration and invasion of pancreatic cancer cells through the induction of apoptosis and blockade of various kinases independent of the Notch1 pathway. Combined JAG1 silencing and gemcitabine treatment showed synergistic anti-viability effects in human pancreatic cancer cells. JAG1 silencing also resulted in significant anti-cancer effects in vivo and high JAG1 expression was found to be associated with an adverse prognosis in pancreatic cancer patients.

CONCLUSIONS

From our data we conclude that JAG1 may be a promising therapeutic target in pancreatic cancer.

Upregulation of DUSP14 Affects Proliferation, Invasion and Metastasis, Potentially via Epithelial-Mesenchymal Transition and Is Associated with Poor Prognosis in Pancreatic Cancer

Background

There is a growing number of evidence which report the relationship of the dual-specificity phosphatases 14 (DUSP14) with physiological and pathological mechanisms in the human body. However, it is still not known what if any role DUSP14 plays in pancreatic cancer.

Materials and Methods

The study evaluates the levels of DUSP14 in the pancreatic cancer tissues and cell lines using Western blotting and qRT-PCR to assess the levels of the DUSP14 and epithelial–mesenchymal transition (EMT) biomarkers. After the DUSP14 was blocked, the following assays were performed: colony formation, assessments of scratch wound and transwell to examine the effects of DUSP14 on the proliferation, migration and invasion of the pancreatic cancer.

Results

Results showed that there was a significant increase in the level of DUSP14 expression both in the pancreatic cancer tissues and cell lines. Experimental downregulation of DUSP14 induced the inhibition of the capacity of proliferation, migration and invasion of the pancreatic cancer cells. Western blotting analyses showed changes in the levels of expression of the EMT biomarkers, which helped to determine the function of DUSP14 in EMT.

Conclusion

In conclusion, we suggest that DUSP14 is a novel molecular target that can be used for the treatment of pancreatic cancer.

Differential Dependency of Human Pancreatic Cancer Cells on Targeting PTEN via PLK 1 Expression

Even though the tumour suppressive role of PTEN is well-known, its prognostic implications are ambiguous. The objective of this study was to further explore the function of PTEN expression in human pancreatic cancer. The expression of PTEN has been dominant in various human cancers including pancreatic cancer when compared with their matched normal tissues. The pancreatic cancer cells have been divided into PTEN blockade-susceptible and PTEN blockade-impassible groups dependent on targeting PTEN by altering intracellular signaling. The expression of PTEN has led to varying clinical outcomes of pancreatic cancer based on GEO Series (GSE) data analysis and Liptak’s z analysis. Differential dependency to PTEN blockade has been ascertained based on the expression of polo-like kinase1 PLK1 in pancreatic cancer cells. The prognostic value of PTEN also depends on PLK1 expression in pancreatic cancer. Collectively, the present study provides a rationale for targeting PTEN as a promising therapeutic strategy dependent on PLK1 expressions using a companion biomarker discovery platform.

Scattered DUSP28 is a novel biomarker responsible for aggravating malignancy via the autocrine and paracrine signaling in metastatic pancreatic cancer

Pancreatic cancer remains one of the most dangerous cancers with a grave prognosis. We have reported that dual specificity phosphatise 28 (DUSP28) could be secreted in pancreatic cancer cells. However, its biological function is poorly understood. Here, we distinguish the function of scattered DUSP28 in human pancreatic cancer. DUSP28 was specifically secreted to cultured medium in metastatic pancreatic cancer cells. Treatment with recombinant DUSP28 significantly increased the migration, invasion, and viability of metastatic pancreatic cancer cells through the activation of CREB, AKT, and ERK1/2 signaling pathways. In addition, administration of recombinant DUSP28 elicited pro-angiogenic effects in human umbilical vein endothelial cells. Injection of recombinant DUSP28 also produced tumor growth in vivo. Of interest, DUSP28 formed an autocrine loop with integrin α1 (ITGα1) by transcriptional regulation and recombinant DUSP28 acted as an oncogenic reagent through the interaction with ITGα1. Notably, scattered DUSP28 could be detected in whole blood samples of pancreatic cancer patients by accessible immunoassay. These results provide the basis for DUSP28 as a promising therapeutic target and a biomarker for metastatic pancreatic cancer.

Combined administration of naringenin and hesperetin with optimal ratio maximizes the anti-cancer effect in human pancreatic cancer via down regulation of FAK and p38 signaling pathway

BACKGROUND

We have previously reported the functional anti-cancer effects of the products of enzymatic hydrolysis of Citrus unshiu peel (εCUP) and fermented extraction of Citrus unshiu peel (ƒCUP) in human pancreatic cancer. Despite their different characteristics and effects, the underlying mechanism remains elusive.

PURPOSE

In this study, we further demonstrate the impact of ingredient contents of Citrus unshiu peel on the cancer's natural features.

METHODS

Anti-pancreatic cancer activities following combined treatment of naringenin and hesperetin were demonstrated in vitro and in vivo experiments.

RESULTS

Combined treatment with naringenin and hesperetin inhibited the growth of human pancreatic cancer cells (εCUP mimic condition, p < 0.001 for Miapaca-2 cells) through induction of caspase-3 cleavage compared to separate treatment with naringenin or hesperetin. Combined treatment with naringenin and hesperetin also inhibited the migration (εCUP mimic condition, p < 0.001 for Panc-1 cells) of human pancreatic cancer cells. The εCUP mimic condition had the most effective anti-cancer features; in contrast, which had no inhibitory effect on growth and migration of normal cells (HUVECs and Detroit551 cells). In addition, εCUP mimic condition inhibited the phosphorylation of focal adhesion kinase (FAK) and p38 signaling compared with separate treatment with naringenin or hesperetin. Of note, εCUP mimic condition showed a prominent anti-growth effect (p < 0.001) compared with control or ƒCUP mimic condition in vivo xenograft models.

CONCLUSION

These results suggest that combined treatment with naringenin and hesperetin might be a promising anti-cancer strategy for pancreatic cancers without eliciting toxicity on normal cells.

Blockade of integrin α3 attenuates human pancreatic cancer via inhibition of EGFR signalling

The prognosis of pancreatic cancer remains dismal despite continuous and considerable efforts. Integrins (ITGs) are highly expressed in various malignant cancers. However, very few studies investigated the role of integrin α3 (ITGα3) in malignant cancers. Here, we determined the functional role of ITGα3 in pancreatic cancer. Analysis of public microarray databases and Western blot analysis indicated a unique expression of ITGα3 in human pancreatic cancer. Silencing ITGα3 expression significantly inhibited the viability and migration of human pancreatic cancer cells. Notably, ablation of ITGα3 expression resulted in a significant decrease of epidermal growth factor receptor (EGFR) expression compared with transfection of control-siRNA through an increased number of leucine-rich repeats and immunoglobulin-like domain protein 1 (LRIG1) expression. In addition, ablating ITGα3 inhibited tumour growth via blockade of EGFR signalling in vivo. Furthermore, the highly expressed ITGα3 led to a poor prognosis of pancreatic cancer patients. Our results provide novel insights into ITGα3-induced aggressive pancreatic cancer.

Fermented Extraction of Citrus unshiu Peel Inhibits Viability and Migration of Human Pancreatic Cancers

Pancreatic cancer is one of the most dangerous cancers with high mortality rates. Despite continuous efforts, there has been limited improvement in its prognosis. In this study, we prepared fermented extract of Citrus unshiu peel (fCUP) from the by-product after juice processing and then examined the anticancer effects of fCUP on human pancreatic cancer cells. Treatment with fCUP inhibited the growth of human pancreatic cancer cells through induction of caspase-3 cleavage both in vitro and in vivo. Treatment with fCUP also blocked the migration of human pancreatic cancer cells through activation of intracellular signaling pathways such as MKK3/6 and P38. In contrast, treatment with fCUP did not inhibit growth and migration of human umbilical vein endothelial cells. In addition, we found that fCUP mainly consisted of aboriginal compounds, narirutin and hesperidin, as well as newly generated compounds, naringenin and hesperetin. In silico analysis showed that naringenin and hesperetin were the unique modules related to anticancer effect. Furthermore, fCUP exhibited the anticancer effects in in vivo xenograft models. Collectively, these results suggest that fCUP might have the potential to be developed into an effective anticancer drug for pancreatic cancers without causing adverse side-effects.

Structural and biochemical analysis of atypically low dephosphorylating activity of human dual-specificity phosphatase 28

Dual-specificity phosphatases (DUSPs) constitute a subfamily of protein tyrosine phosphatases, and are intimately involved in the regulation of diverse parameters of cellular signaling and essential biological processes. DUSP28 is one of the DUSP subfamily members that is known to be implicated in the progression of hepatocellular and pancreatic cancers, and its biological functions and enzymatic characteristics are mostly unknown. Herein, we present the crystal structure of human DUSP28 determined to 2.1 Å resolution. DUSP28 adopts a typical DUSP fold, which is composed of a central β-sheet covered by α-helices on both sides and contains a well-ordered activation loop, as do other enzymatically active DUSP proteins. The catalytic pocket of DUSP28, however, appears hardly accessible to a substrate because of the presence of nonconserved bulky residues in the protein tyrosine phosphatase signature motif. Accordingly, DUSP28 showed an atypically low phosphatase activity in the biochemical assay, which was remarkably improved by mutations of two nonconserved residues in the activation loop. Overall, this work reports the structural and biochemical basis for understanding a putative oncological therapeutic target, DUSP28, and also provides a unique mechanism for the regulation of enzymatic activity in the DUSP subfamily proteins.

Autocrine DUSP28 signaling mediates pancreatic cancer malignancy via regulation of PDGF-A

Pancreatic cancer remains one of the most deadly cancers with a grave prognosis. Despite continuous efforts to improve remedial values, limited progress has been made. We have reported that dual specificity phosphatase 28 (DUSP28) has a critical role of chemo-resistance and migration in pancreatic cancers. However, its mechanism remains unclear. Here, we further clarify the function of DUSP28 in pancreatic cancers. Analysis using a public microarray database and in vitro assay indicated a critical role of platelet derived growth factor A (PDGF-A) in pancreatic cancer malignancy. PDGF-A was positively regulated by DUSP28 expression at the mRNA and protein levels. Enhanced DUSP28 sensitized pancreatic cancer cells to exogenous PDGF-A treatment in migration, invasion, and proliferation. Transfection with siRNA targeting DUSP28 blunted the influence of administered PDGF-A by inhibition of phosphorylation of FAK, ERK1/2, and p38 signalling pathways. In addition, DUSP28 and PDGF-A formed an acquired autonomous autocrine-signaling pathway. Furthermore, targeting DUSP28 inhibited the tumor growth and migratory features through the blockade of PDGF-A expression and intracellular signaling in vivo. Our results establish novel insight into DUSP28 and PDGF-A related autonomous signaling pathway in pancreatic cancer.

Critical Roles of Dual-Specificity Phosphatases in Neuronal Proteostasis and Neurological Diseases

Protein homeostasis or proteostasis is a fundamental cellular property that encompasses the dynamic balancing of processes in the proteostasis network (PN). Such processes include protein synthesis, folding, and degradation in both non-stressed and stressful conditions. The role of the PN in neurodegenerative disease is well-documented, where it is known to respond to changes in protein folding states or toxic gain-of-function protein aggregation. Dual-specificity phosphatases have recently emerged as important participants in maintaining balance within the PN, acting through modulation of cellular signaling pathways that are involved in neurodegeneration. In this review, we will summarize recent findings describing the roles of dual-specificity phosphatases in neurodegeneration and offer perspectives on future therapeutic directions.

Dual Specificity Phosphatase 5-Substrate Interaction: A Mechanistic Perspective

The mammalian genome contains approximately 200 phosphatases that are responsible for catalytically removing phosphate groups from proteins. In this review, we discuss dual specificity phosphatase 5 (DUSP5). DUSP5 belongs to the dual specificity phosphatase (DUSP) family, so named after the family members' abilities to remove phosphate groups from serine/threonine and tyrosine residues. We provide a comparison of DUSP5's structure to other DUSPs and, using molecular modeling studies, provide an explanation for DUSP5's mechanistic interaction and specificity toward phospho-extracellular regulated kinase, its only known substrate. We also discuss new insights from molecular modeling studies that will influence our current thinking of mitogen-activated protein kinase signaling. Finally, we discuss the lessons learned from identifying small molecules that target DUSP5, which might benefit targeting efforts for other phosphatases. © 2017 American Physiological Society. Compr Physiol 7:1449-1461, 2017.

Aqueous Extraction of Citrus unshiu Peel Induces Proangiogenic Effects Through the FAK and ERK1/2 Signaling Pathway in Human Umbilical Vein Endothelial Cells

Citrus unshiu peel has been used empirically as a traditional medicine to improve bronchial asthma and blood circulation in northeast Asian nations, including Korea, Japan, and China. In this study, we report the proangiogenic effects of the aqueous extract of Citrus unshiu peel (AECUP). In human umbilical vein endothelial cells, AECUP significantly induced cellular migration and capillary tube formation. We also demonstrated that AECUP markedly increased the phosphorylation of FAK and ERK1/2 through the integrin signaling pathway. Additionally, we identified that narirutin and hesperidin were major constituents of AECUP and both showed proangiogenic effects, but at different levels. Collectively, these results suggest that the AECUP may have potential as a therapeutic agent for improving angiogenic functions with reduced harmful side effects.

Genomic and transcriptomic profiles and in vitro resistance to mitoxantrone and idarubicin in pediatric acute leukemias

BACKGROUND

A major problem in the treatment of leukemia is the development of drug resistance to chemotherapeutic agents.

METHODS

To determine the ex vivo drug resistance profile to anthracyclines, an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazoliumbromide (MTT) cytotoxicity assay was performed on mononuclear cells obtained from 155 patients with acute lymphoblastic leukemia (ALL) or acute myeloblastic leukemia (AML). Gene expression profiles (for 51 patients with ALL and 16 with AML) were prepared on the basis of cRNA hybridization to oligonucleotide arrays of the human genome (Affymetrix). Hierarchical clustering, assignment location and biological function were investigated during the correlation analysis for identified probe sets. Comparative genomic hybridization (CGH) array profiles (34 patients with ALL and 12 with AML) were prepared on the basis of DNA hybridization to oligonucleotide arrays of the human genome (Agilent). The validation of the array results was performed by a quantitative reverse transcriptase polymerase chain reaction.

RESULTS

The collected expression and CGH microarray experiment results indicate that the ITGB2, SCL6A7, CASP1 and DUSP genes may comprise a resistance marker for acute leukemia cells correlated with anthracyclines. Moreover, there were also identified chromosome rearrangements associated with drug resistance, such as del5q32-35.3 and amp8p12-p11.21. Precise genes, as well as genome aberrations, might be classified as targets in therapy.

CONCLUSIONS

In AML, the resistance of blasts to idarubicin and mitoxantrone may reflect an impaired integrin pathway. In ALL, the development of resistance is caused by the inhibition of B and T cell activation. Copyright © 2016 John Wiley & Sons, Ltd.

DUSP28 links regulation of Mucin 5B and Mucin 16 to migration and survival of AsPC-1 human pancreatic cancer cells

The prognosis of pancreatic cancer has not improved despite considerable and continuous effort. Dual-specificity phosphatase 28 (DUSP28) is highly expressed in human pancreatic cancers and exerts critical effects. However, knowledge of its function in pancreatic cancers is extremely limited. Here, we demonstrate the peculiar role of DUSP28 in pancreatic cancers. Analysis using the Gene Expression Omnibus public microarray database indicated higher DUSP28, MUC1, MUC4, MUC5B, MUC16 and MUC20 messenger RNA (mRNA) levels in pancreatic cancers compared with normal pancreas tissues. DUSP28 expression in human pancreatic cancer correlated positively with those of MUC1, MUC4, MUC5B, MUC16 and MUC20. In contrast, there were no significant correlations between DUSP28 and mucins in normal pancreas tissues. Decreased DUSP28 expression resulted in down-regulation of MUC5B and MUC16 at both the mRNA and protein levels; furthermore, transfection with small interfering RNA (siRNA) for MUC5B and MUC16 inhibited the migration and survival of AsPC-1 cells. In addition, transfection of siRNA for MUC5B and MUC16 resulted in a significant decrease in phosphorylation of FAK and ERK1/2 compared with transfection with scrambled-siRNA. These results collectively indicate unique links between DUSP28 and MUC5B/MUC16 and their roles in pancreatic cancer; moreover, they strongly support a rationale for targeting DUSP28 to inhibit development of malignant pancreatic cancer.

Kaempferol Inhibits Pancreatic Cancer Cell Growth and Migration through the Blockade of EGFR-Related Pathway In Vitro

Pancreatic cancer is one of the most appalling cancers with a pessimistic prognosis. Despite many therapies, there has been no improvement of survival rates. In this study, we assessed the anti-cancer effects of kaempferol, a well known flavonoid having functional bio-activity against various malignant tumors. Kaempferol had anti-cancer effects on Miapaca-2, Panc-1, and SNU-213 human pancreatic cancer cells. In a dose-dependent manner, kaempferol decreased viability of these pancreatic cancer cells by increasing apoptosis. In particular, kaempferol effectively inhibited the migratory activity of human pancreatic cancer cells at relatively low dosages without any toxicity. The anti-cancer effect of kaempferol was mediated by inhibition of EGFR related Src, ERK1/2, and AKT pathways. These results collectively indicate that kaempferol, a phytochemical ingredient reported to have anti-viability and anti-oxidant properties, can act as a safety anti-migration reagent in human pancreatic cancer cells, which provide the rationale for further investigation of kaempferol as a strong candidate for the potential clinical trial of malignant pancreatic cancers.

Integrin β6 acts as an unfavorable prognostic indicator and promotes cellular malignant behaviors via ERK-ETS1 pathway in pancreatic ductal adenocarcinoma (PDAC)

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most deadly cancers and is expected to become the second leading cause of cancer death by 2030. Despite extensive efforts to improve surgical treatment, limited progress has been made. Increasing evidence indicates that integrin β6 plays a crucial role in carcinoma invasion and metastasis. However, the expression and role of β6 in PDAC remain largely unknown. In the present study, we investigated the expression of β6 in PDAC and its potential value as a prognostic factor and therapeutic target. β6 upregulation was identified as an independent unfavorable prognostic indicator. Integrin β6 markedly promoted the proliferation and invasion of pancreatic carcinoma cells and induced ETS1 phosphorylation in an ERK-dependent manner, leading to the upregulation of matrix metalloprotease-9, which is essential for β6-mediated invasiveness of pancreatic carcinoma cells. Accordingly, small interfering RNA-mediated silencing of integrin β6 markedly suppressed xenograft tumor growth in vivo. Taken together, our results suggest that integrin β6 plays important roles in the progression of pancreatic carcinoma and contributes to reduced survival times, and may serve as a novel therapeutic target for the treatment of PDAC.