Molecular and Cellular Pathobiology Hypoxia-Inducible Factor-1 Promotes Pancreatic Ductal Adenocarcinoma Invasion and Metastasis by Activating Transcription of the Actin-Bundling Protein Fascin

Because of the early onset of local invasion and distant metastasis, pancreatic ductal adenocarcinoma (PDAC) is the most lethal human malignant tumor, with a 5-year survival rate of less than 5%. In this study, we investigated the role of fascin, a prometastasis actin-bundling protein, in PDAC progression, invasion, and the molecular mechanisms underlying fascin overexpression in PDAC. Our data showed that the expression levels of fascin were higher in cancer tissues than in normal tissues, and fascin overexpression correlated with the PDAC differentiation and prognosis. Fascin overexpression promoted PDAC cell migration and invasion by elevating matrix metalloproteinase-2 (MMP-2) expression. Fascin regulated MMP-2 expression through protein kinase C and extracellular signal—regulated kinase. Importantly, our data showed that hypoxia induced fascin overexpression in PDAC cells by promoting the binding of hypoxia-inducible factor-1 (HIF-1) to a hypoxia response element on the fascin promoter and transactivating fascin mRNA transcription. Intriguingly, HIF-1a expression levels in PDAC patient specimens significantly correlated with fascin expression. Moreover, immunohistochemistry staining of consecutive sections demonstrated colocalization between HIF-1a and fascin in PDAC specimens, suggesting that hypoxia and HIF-1a were responsible for fascin overexpression in PDAC. When ectopically expressed, fascin was able to rescue PDAC cell invasion after HIF-1a knockdown. Our results demonstrated that fascin is a direct target gene of HIF-1. Our data suggested that the hypoxic tumor microenvironment in PDAC might promote invasion and metastasis by inducing fascin overexpression, and fascin might be targeted to block PDAC progression. Cancer Res; 74(9); 2455–64. 2014 AACR. Introduction Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal human malignancies with a 5-year survival rate of less than 5% (1). The poor prognosis in PDAC is mainly due to early onset of local invasion and distant metastasis. Therefore, it is important to understand the cellular and molecular mechanisms that regulate tumor invasion and metastasis to develop better treatment regimens. Hypoxia is most commonly presented in the microenvironment of solid tumors (2). Hypoxia-inducible factor-1 (HIF-1; consists of highly regulated HIF-1a and a constitutively expressed HIF-1b) is the most important transcription factor as a result of intratumoral hypoxia, which can mediate many adaptive physiologic responses (3). In pancreatic cancer, HIF1a expression levels are associated with tumor progression, fibrotic focus, angiogenesis cell migration, and hepatic metastasis (4–6). Fascin is an actin-bundling protein that crosslinks actin filaments into tight, parallel bundles in filopodia and invadopodia (7–9). At the cellular level, fascin is highly expressed in filopodia-rich cell types such as neurons,mature dendritic cells (10), but not expressed in the normal simple columnar epithelia of biliary duct, breast, colon, ovary, pancreas, and stomach. However, the absence or low expression of fascin in normal epithelia is dramatically altered in many human carcinomas (11). There is evidence suggesting that fascin is overexpressed in PDAC (12–14), and fascin overexpression resulted in enhanced motility, scattering, and invasiveness of pancreatic cancer cells (15). However, molecular mechanisms underlying fascin overexpression in PDAC is not clear, and the role of fascin in PDAC progression is not fully understood. In this study, we aimed to investigate (i) the mechanism of fascin regulation by hypoxia, (ii) the role of fascin in the Authors' Affiliations: Department of Pancreatic Carcinoma, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin, China; and Department of Tumor Biology and Comprehensive Melanoma Research Center, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida Note: Supplementary data for this article are available at Cancer Research Online (http://cancerres.aacrjournals.org/). X. Zhao and S. Gao contributed equally to this work. Corresponding Author: Jihui Hao, Department of Pancreatic Carcinoma, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center of Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China. Phone: 86-022-23340123; Fax: 86-02223340123; E-mail: [email protected] doi: 10.1158/0008-5472.CAN-13-3009 2014 American Association for Cancer Research. Cancer Research www.aacrjournals.org 2455 on July 19, 2017. © 2014 American Association for Cancer Research. cancerres.aacrjournals.org Downloaded from Published OnlineFirst March 5, 2014; DOI: 10.1158/0008-5472.CAN-13-3009