title: Hepatocyte growth factor activator inhibitor type 1 regulates epithelial to mesenchymal transition through membrane-bound serine proteinases.
abstract: Hepatocyte growth factor activator inhibitor-1 (HAI-1), encoded by the serine protease inhibitor Kunitz type 1 (SPINT1) gene, is a membrane-associated proteinase inhibitor that potently inhibits a variety of serine proteinases, including those that are membrane bound. Although HAI-1/SPINT1 is widely expressed by epithelial cells and cancer cells, its functional role is still unclear, particularly in cancer. Here, we show that stable knockdown of HAI-1/SPINT1 in the human pancreatic cancer cell line SUIT-2 induces an elongated spindle-like morphology associated with accelerated invasion, thereby mimicking an epithelial to mesenchymal transition (EMT). We found that HAI-1/SPINT1 knockdown significantly reduced the expression of E-cadherin and was accompanied by up-regulation of Smad-interacting protein 1 (SIP1), an E-cadherin transcriptional repressor. In addition, matrix metalloproteinase-9 (MMP-9) was up-regulated. Similar results were obtained in the HLC-1 lung carcinoma cell line. Moreover, a metastatic variant of SUIT-2 (S2-CP8) that showed loss of E-cadherin expression also showed a significantly reduced level of HAI-1/SPINT1. Engineered overexpression of HAI-1/SPINT1 in S2-CP8 resulted in reversion of E-cadherin expression and SIP1 down-regulation, which accompanied reestablishment of epithelial morphology in culture. The EMT caused by HAI-1/SPINT1 knockdown seemed to be mediated, at least partly, by membrane-bound serine proteinases, matriptase/ST14 and TMPRSS4, as knockdown of matriptase/ST14 or TMPRSS4 in HAI-1/SPINT1 knockdown SUIT-2 cells and HLC-1 cells resulted in reversion of SIP1 and/or MMP-9 expression levels. We suggest that interactions between HAI-1/SPINT1 and membrane-bound serine proteinases contribute to transcriptional and functional changes involved in EMT in certain carcinoma cells.
authors.affiliation: Section of Oncopathology and Regenerative Biology, Department of Pathology, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan.
authors.forename: Haixia
authors.initials: H
authors.lastname: Cheng
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Fukushima
authors.forename: Nobuyasu
authors.initials: N
authors.lastname: Takahashi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tanaka
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kataoka
mesh_terms: D000818:Animals; D015820:Cadherins / Q000235:genetics; D045744:Cell Line, Tumor; D004847:Epithelial Cells / Q000473:pathology*; D006801:Humans; D008297:Male; D008648:Mesoderm / Q000473:pathology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009369:Neoplasms / Q000473:pathology*; D009419:Nerve Tissue Proteins / Q000502:physiology; D010190:Pancreatic Neoplasms / Q000473:pathology; D053491:Proteinase Inhibitory Proteins, Secretory / Q000235:genetics / Q000502:physiology*; D016601:RNA-Binding Proteins / Q000502:physiology; D012697:Serine Endopeptidases / Q000502:physiology*; D016212:Transforming Growth Factor beta / Q000502:physiology
chemical_list: D015820:Cadherins; C108381:GEMIN2 protein, human; D009419:Nerve Tissue Proteins; D053491:Proteinase Inhibitory Proteins, Secretory; D016601:RNA-Binding Proteins; C109149:SPINT1 protein, human; D016212:Transforming Growth Factor beta; D012697:Serine Endopeptidases