Expression of hepatocyte growth factor activator inhibitor type 1 on the epithelial cell surface is regulated by hypoxic and oxidative stresses

Molecular characteristics of varicocele: integration of whole-exome and transcriptome sequencing

OBJECTIVE

To explore the exome and transcriptome characteristics potentially underlying the pathogenesis of varicocele (VE).

DESIGN

Experimental study and cohort study.

SETTING

Academic research laboratory and university-affiliated hospital.

PATIENT(S)

Eleven VE patients whose fathers also had VE, plus 151 additional patients and 324 healthy men for variants genotyping; for the rat model, eight Sprague-Dawley male rats.

INTERVENTION(S)

Partial ligation of renal vein was conducted to establish VE rat models for whole-transcriptome RNA sequencing (RNA-seq).

MAIN OUTCOME MEASURE(S)

Genes with differential expression and/or harboring potential pathogenic variants detected via RNA-seq and whole-exome sequencing (WES) then subjected to population-based survey to define candidate genes of VE and analyzed via Gene Ontology and Kyoto Encyclopedia of Genes and Genomes to identify VE-involved pathways.

RESULT(S)

Whole-transcriptome RNA sequencing (RNA-seq) was performed using left spermatic veins of five rat VE models and three controls. We identified 9,688 genes and 18 pathways via RNA-seq, and via WES 160 genes harboring 279 potential deleterious variants and 16 pathways. Nine genes (AAMP, KMT2D, IRS2, SPINT1, IFT122, MKI67, DCHS1, LAMA2, and CBL) had variants in more than one patient who underwent WES, and six of these genes (AAMP, SPINT1, MKI67, IFT122, LAMA2, and DCHS1) showed differential expression. The population-based survey showed that AAMP, SPINT1, and MKI67 were strongly associated with VE risk. Together, two omic 67 data sets revealed four pathways potentially related to VE.

CONCLUSION(S)

For the first time, we have described the exome and transcriptome characteristics of VE. The bi-omics identified novel candidate genes and pathways involving the occurrence and development of VE.

Intestinal regulation of suppression of tumorigenicity 14 (ST14) and serine peptidase inhibitor, Kunitz type -1 (SPINT1) by transcription factor CDX2

The type II membrane-anchored serine protease, matriptase, encoded by suppression of tumorgenicity-14 (ST14) regulates the integrity of the intestinal epithelial barrier in concert with its inhibitor, HAI-1 encoded by serine peptidase inhibitor, Kunitz type -1 (SPINT1). The balance of the protease/inhibitor gene expression ratio is vital in preventing the oncogenic potential of matriptase. The intestinal cell lineage is regulated by a transcriptional regulatory network where the tumor suppressor, Caudal homeobox 2 (CDX2) is considered to be an intestinal master transcription factor. In this study, we show that CDX2 has a dual function in regulating both ST14 and SPINT1, gene expression in intestinal cells. We find that CDX2 is not required for the basal ST14 and SPINT1 gene expression; however changes in CDX2 expression affects the ST14/SPINT1 mRNA ratio. Exploring CDX2 ChIP-seq data from intestinal cell lines, we identified genomic CDX2-enriched enhancer elements for both ST14 and SPINT1, which regulate their corresponding gene promoter activity. We show that CDX2 displays both repressive and enhancing regulatory abilities in a cell specific manner. Together, these data reveal new insight into transcriptional mechanisms controlling the intestinal matriptase/inhibitor balance.

Expression of serine peptidase inhibitor Kunitz type 1 in differentiated thyroid cancer

SPINT1, also known as HAI-1, is a Kunitz-type serine protease inhibitor that inhibits multiple proteases including hepatocyte growth factor (HGF) activator and matriptase. SPINT1 has been shown to modulate HGF/MET activation in certain cancer types. In the present study, we analyzed microarray datasets and found that SPINT1 was consistently upregulated in differentiated thyroid cancer. SPINT1 protein expression was investigated using tissue microarrays and independent samples of our 143 patients. Strong SPINT1 expression was observed in 61-68% of papillary thyroid cancer and 41-50% of follicular thyroid cancer. The overexpression diminished in anaplastic thyroid cancer. The SPINT1 expression in normal thyroid tissues and benign thyroid lesions was low. Furthermore, we noted that the SPINT1 expression was associated with extrathyroidal invasion, lymphovascular invasion, lymph node metastasis, advanced TNM stage, and a higher risk of recurrence in differentiated thyroid cancer. The results were in accordance with our analysis of The Cancer Genome Atlas data. In conclusion, an overexpression of SPINT1 appears to be associated with an invasive phenotype in differentiated thyroid cancer.

Mechanisms of hepatocyte growth factor activation in cancer tissues

Hepatocyte growth factor/scatter factor (HGF/SF) plays critical roles in cancer progression through its specific receptor, MET. HGF/SF is usually synthesized and secreted as an inactive proform (pro-HGF/SF) by stromal cells, such as fibroblasts. Several serine proteases are reported to convert pro-HGF/SF to mature HGF/SF and among these, HGF activator (HGFA) and matriptase are the most potent activators. Increased activities of both proteases have been observed in various cancers. HGFA is synthesized mainly by the liver and secreted as an inactive pro-form. In cancer tissues, pro-HGFA is likely activated by thrombin and/or human kallikrein 1-related peptidase (KLK)-4 and KLK-5. Matriptase is a type II transmembrane serine protease that is expressed by most epithelial cells and is also synthesized as an inactive zymogen. Matriptase activation is likely to be mediated by autoactivation or by other trypsin-like proteases. Recent studies revealed that matriptase autoactivation is promoted by an acidic environment. Given the mildly acidic extracellular environment of solid tumors, matriptase activation may, thus, be accelerated in the tumor microenvironment. HGFA and matriptase activities are regulated by HGFA inhibitor (HAI)-1 (HAI-1) and/or HAI-2 in the pericellular microenvironment. HAIs may have an important role in cancer cell biology by regulating HGF/SF-activating proteases.

Loss of hepatocyte growth factor activator inhibitor type 1 participates in metastatic spreading of human pancreatic cancer cells in a mouse orthotopic transplantation model

Hepatocyte growth factor activator inhibitor type 1 (HAI-1) is a membrane-bound serine protease inhibitor that is expressed on the surface of epithelial and carcinoma cells. On the cell surface, HAI-1 regulates membrane-anchored serine proteases, with matriptase being the most critical target. Matriptase is involved in pericellular processing of biologically active molecules, including protease-activated receptor-2 (PAR-2). Previously we reported that S2-CP8 cells, a metastatic variant of the SUIT-2 human pancreatic adenocarcinoma cell line, showed markedly decreased HAI-1 expression. To assess the significance of HAI-1 loss in invasion and spontaneous metastasis of S2-CP8 cells, we established stable S2-CP8 sublines that expressed HAI-1 under the control of a tetracycline-regulated promoter. In vitro migration and invasion assays revealed inhibitory effects of HAI-1 on S2-CP8 cell migration and invasion. Matriptase activity was suppressed by the expression of HAI-1. As the enhanced invasiveness in the absence of HAI-1 was alleviated by knockdown of matriptase by 81% and of PAR-2 completely, and PAR-2 antagonist also suppressed the invasion, matriptase-mediated PAR-2 activation is involved in HAI-1 loss-induced invasion of S2-CP8 cells. We then analyzed the effect of HAI-1 expression on metastasis of S2-CP8 cells in vivo using a nude mouse orthotopic xenograft model. Although approximately 50% of the control mice developed distant metastasis, mice treated with doxycycline to induce HAI-1 expression did not develop metastasis. These data indicate that HAI-1 loss contributes to invasion and dissemination of a highly metastatic subline of SUIT-2, suggesting crucial roles for the balance of pericellular serine proteases/inhibitors in pancreatic cancer progression.

Tissue injury alters the site of expression of hepatocyte growth factor activator inhibitor type 1 in bronchial epithelial cells

Hepatocyte growth factor activator inhibitor-1 (HAI-1) is a Kunitz-type transmembrane serine proteinase inhibitor that inhibits trypsin-like serine proteinases, such as hepatocyte growth factor activator, matriptase, hepsin and prostasin. HAI-1 is expressed in polarized epithelial cells, in which HAI-1 is mainly located on the basolateral membrane. In the present study, we analyzed the expression and distribution of HAI-1 in respiratory epithelium. We found that HAI-1 is expressed by the bronchial respiratory epithelium with basal or basolateral localization and also by the alveolar epithelium. Bronchial expression of HAI-1 was also confirmed using cultured human bronchial epithelial cells. The epithelial expression of HAI-1 was augmented in response to tissue injury such as cancer invasion and inflammation. Surprisingly, in the injured pulmonary tissue, HAI-1 showed distinct apical translocation in ciliated epithelial cells of the bronchiole. We suggest that, in addition to its basolateral surface localization, HAI-1 can transiently localize to the apical surface of respiratory ciliated epithelial cells under conditions of severe inflammation, possibly interacting with a specific cellular proteinase on the apical surface.