Paradoxically enhanced immunoreactivity of hepatocyte growth factor activator inhibitor type 1 (HAI-1) in cancer cells at the invasion front

Protease-activated receptor-2 accelerates intestinal tumor formation through activation of nuclear factor-κB signaling and tumor angiogenesis in ApcMin/+ mice

Hepatocyte growth factor activator inhibitor‐1 (HAI‐1), encoded by the SPINT1 gene, is a membrane‐bound protease inhibitor expressed on the surface of epithelial cells. Hepatocyte growth factor activator inhibitor‐1 regulates type II transmembrane serine proteases that activate protease‐activated receptor‐2 (PAR‐2). We previously reported that deletion of Spint1 in Apc^Min/+ mice resulted in accelerated formation of intestinal tumors, possibly through enhanced nuclear factor‐κB signaling. In this study, we examined the role of PAR‐2 in accelerating tumor formation in the Apc^Min/+ model in the presence or absence of Spint1. We observed that knockout of the F2rl1 gene, encoding PAR‐2, not only eliminated the enhanced formation of intestinal tumors caused by Spint1 deletion, but also reduced tumor formation in the presence of Spint1. Exacerbation of anemia and weight loss associated with HAI‐1 deficiency was also normalized by compound deficiency of PAR‐2. Mechanistically, signaling triggered by deregulated protease activities increased nuclear translocation of RelA/p65, vascular endothelial growth factor expression, and vascular density in Apc^Min/+‐induced intestinal tumors. These results suggest that serine proteases promote intestinal carcinogenesis through activation of PAR‐2, and that HAI‐1 plays a critical tumor suppressor role as an inhibitor of matriptase, kallikreins, and other PAR‐2 activating proteases.

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.

Hepatocyte growth factor activator inhibitors (HAI-1 and HAI-2): Emerging key players in epithelial integrity and cancer

The growth, survival, and metabolic activities of multicellular organisms at the cellular level are regulated by intracellular signaling, systemic homeostasis and the pericellular microenvironment. Pericellular proteolysis has a crucial role in processing bioactive molecules in the microenvironment and thereby has profound effects on cellular functions. Hepatocyte growth factor activator inhibitor type 1 (HAI-1) and HAI-2 are type I transmembrane serine protease inhibitors expressed by most epithelial cells. They regulate the pericellular activities of circulating hepatocyte growth factor activator and cellular type II transmembrane serine proteases (TTSPs), proteases required for the activation of hepatocyte growth factor (HGF)/scatter factor (SF). Activated HGF/SF transduces pleiotropic signals through its receptor tyrosine kinase, MET (coded by the proto-oncogene MET), which are necessary for cellular migration, survival, growth and triggering stem cells for accelerated healing. HAI-1 and HAI-2 are also required for normal epithelial functions through regulation of TTSP-mediated activation of other proteases and protease-activated receptor 2, and also through suppressing excess degradation of epithelial junctional proteins. This review summarizes current knowledge regarding the mechanism of pericellular HGF/SF activation and highlights emerging roles of HAIs in epithelial development and integrity, as well as tumorigenesis and progression of transformed epithelial cells.

Engineering a potent inhibitor of matriptase from the natural hepatocyte growth factor activator inhibitor type-1 (HAI-1) protein

Dysregulated matriptase activity has been established as a key contributor to cancer progression through its activation of growth factors, including the hepatocyte growth factor (HGF). Despite its critical role and prevalence in many human cancers, limitations to developing an effective matriptase inhibitor include weak binding affinity, poor selectivity, and short circulating half-life. We applied rational and combinatorial approaches to engineer a potent inhibitor based on the hepatocyte growth factor activator inhibitor type-1 (HAI-1), a natural matriptase inhibitor. The first Kunitz domain (KD1) of HAI-1 has been well established as a minimal matriptase-binding and inhibition domain, whereas the second Kunitz domain (KD2) is inactive and involved in negative regulation. Here, we replaced the inactive KD2 domain of HAI-1 with an engineered chimeric variant of KD2/KD1 domains and fused the resulting construct to an antibody Fc domain to increase valency and circulating serum half-life. The final protein variant contains four stoichiometric binding sites that we showed were needed to effectively inhibit matriptase with a K_i of 70 ± 5 pm, an increase of 120-fold compared with the natural HAI-1 inhibitor, to our knowledge making it one of the most potent matriptase inhibitors identified to date. Furthermore, the engineered inhibitor demonstrates a protease selectivity profile similar to that of wildtype KD1 but distinct from that of HAI-1. It also inhibits activation of the natural pro-HGF substrate and matriptase expressed on cancer cells with at least an order of magnitude greater efficacy than KD1.

Hepatocyte growth factor activator inhibitor type‑1 in cancer: advances and perspectives (Review)

Cancer is one of the most common diseases, with high morbidity and mortality rates. Large‑scale efforts have been made to understand the pathogenesis of the disease, particularly in the advanced stages, in order to develop effective therapeutic approaches. Hepatocyte growth factor activator inhibitor type-1 (HAI-1), also known as serine protease inhibitor Kunitz type 1, inhibits the activity of several trypsin-like serine proteases. In particular, HAI-1 suppresses hepatocyte growth factor (HGF) activator and matriptase, resulting in subsequent inhibition of HGF/scatter factor and macrophage‑stimulating protein (MSP). HGF and MSP are involved in cancer development and progression, via the receptors Met receptor tyrosine kinase (RTK) and Ron RTK, respectively. Therefore, HAI-1-mediated downregulation of HGF and MSP signaling may suppress tumorigenesis and progression in certain types of cancers. Abnormal HAI-1 expression levels have been observed in various types of human cancer. The exact function of HAI-1 in cancer pathogenesis, however, has not been fully elucidated. In this review, the focus is on the potential impact of aberrant HAI-1 expression levels on tumorigenesis and progression, the underlying mechanisms, and areas that require further investigation to clarify the precise role of HAI-1 in 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.

Hepatocyte growth factor activator inhibitor type 1 is a suppressor of intestinal tumorigenesis

Hepatocyte growth factor activator inhibitor type 1 (HAI-1/SPINT1) is a membrane-bound serine protease inhibitor expressed on the surface of epithelial cells. Although HAI-1/SPINT1 is abundantly expressed in the intestinal epithelium, its role in intestinal tumorigenesis is not known. In this study, we investigated the role of Hai-1/Spint1 in intestinal tumorigenesis using mouse models. The membranous Hai-1/Spint1 immunoreactivity was decreased in murine Apc(Min/+) tumors and also in carcinogen (azoxymethane treatment followed by dextran sodium sulfate administration)-induced colon tumors compared with the adjacent non-neoplastic epithelium. The decreased immunoreactivity appeared to be due to sheddase activity of membrane-type 1 matrix metalloprotease. Then, we examined the effect of intestine-specific deletion of Spint1 gene on Apc(Min/+) mice. The loss of Hai-1/Spint1 significantly accelerated tumor formation in Apc(Min/+) mice and shortened their survival periods. Activation of HGF was enhanced in Hai-1/Spint1-deficient Apc(Min/+) intestine. Gene expression profiling revealed upregulation of the Wnt/β-catenin signaling circuit, claudin-2 expression, and angiogenesis not only in tumor tissue but also in the background mucosa without macroscopic tumors in Hai-1/Spint1-deficient Apc(Min/+) intestine. Intestinal deletion of Spint1 also enhanced the susceptibility to carcinogen-induced colon tumorigenicity of wild-type Apc mice. Our findings suggest that HAI-1/SPINT1 has a crucial role in suppressing intestinal tumorigenesis, which implies a novel link between epithelial cell surface serine protease inhibitors and protection from carcinogenic stimuli.

Protein expression of matriptase and its cognate inhibitor HAI-1 in human prostate cancer: a tissue microarray and automated quantitative analysis

Recent studies have suggested that matriptase, a transmembrane serine protease and its cognate inhibitor hepatocyte growth factor activator inhibitor-1 (HAI-1) are important in the progression of many cancers. Limited quantitative data are available on these proteins in prostate cancer. To validate the roles of matriptase and HAI-1 in prostate cancer and its progression, a prostate cancer tissue microarray was constructed. The tissue microarray includes 41 localized prostate cancers (Pca_local), 18 aggressive prostate cancers, 18 metastatic prostate cancers, 24 benign prostate hyperplasias, 18 high-grade intraepithelial neoplasias (HGPIN), and 41 benign prostate tissues. The cellular expression levels of matriptase and HAI-1 were quantified using automated quantitative analysis. We found that matriptase expression levels were significantly higher in Pca_local (P<0.0001) and HGPIN (P<0.05) compared with benign prostate tissue. Matriptase levels were significantly decreased in metastatic cancer when compared with all other tissue types (P<0.05). Compared with benign prostate tissue, HAI-1 expression levels were significantly higher in all proliferative prostate diseases (benign prostate hyperplasia, HGPIN, localized and aggressive cancers, and metastases) (P<0.001); yet, no significant differences were found in HAI-1 expression levels among the diseased tissue types. These results suggest that an increase of matriptase may be useful as a marker for detection of Pca_local, whereas a decrease of matriptase expression may signal prostate cancer progression. HAI-1 seems to be a marker of prostate epithelial cell proliferation.

Defect of hepatocyte growth factor activator inhibitor type 1/serine protease inhibitor, Kunitz type 1 (Hai-1/Spint1) leads to ichthyosis-like condition and abnormal hair development in mice

Hepatocyte growth factor activator inhibitor type 1 (HAI-1)/serine protease inhibitor, Kunitz type 1 (SPINT1) is a membrane-bound, serine proteinase inhibitor initially identified as an inhibitor of hepatocyte growth factor activator. It also inhibits matriptase and prostasin, both of which are membrane-bound serine proteinases that have critical roles in epidermal differentiation and function. In this study, skin and hair phenotypes of mice lacking the Hai-1/Spint1 gene were characterized. Previously, we reported that the homozygous deletion of Hai-1/Spint1 in mice resulted in embryonic lethality attributable to impaired placental development. To test the role of Hai-1/Spint1 in mice, the placental function of Hai-1/Spint1-mutant mice was rescued. Injection of Hai-1/Spint1(+/+) blastocysts with Hai-1/Spint1(-/-) embryonic stem cells successfully generated high-chimeric Hai-1/Spint1(-/-) embryos (B6Hai-1(-/-High)) with normal placentas. These embryos were delivered without apparent developmental abnormalities, confirming that embryonic lethality of Hai-1/Spint1(-/-) mice was caused by placental dysfunction. However, newborn B6Hai-1(-/-High) mice showed growth retardation and died by 16 days. These mice developed scaly skin because of hyperkeratinization, reminiscent of ichthyosis, and abnormal hair shafts that showed loss of regular cuticular septation. The interfollicular epidermis showed acanthosis with enhanced Akt phosphorylation. Immunoblot analysis revealed altered proteolytic processing of profilaggrin in Hai-1/Spint1-deleted skin with impaired generation of filaggrin monomers. These findings indicate that Hai-1/Spint1 has critical roles in the regulated keratinization of the epidermis and hair development.

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

Hepatocyte growth factor activator inhibitor type 1 (HAI-1)/spint-1 is a membrane-bound protease inhibitor that is thought to regulate the activities of hepatocyte growth factor activator, matriptase, hepsin, and prostasin. In this study, we show that the membrane form of HAI-1 was significantly upregulated immunohistochemically in epithelial cells under adverse conditions including tissue injury, necroinflammatory reactions, and invasion of carcinomas. To analyze the mechanism underlying these in vivo observations, we examined the effects of hypoxia and oxidative stress on HAI-1 expression in vitro, using three human cell lines, HLC-1, WiDr, and HeLa. Hypoxic condition significantly enhanced the expression of HAI-1 in these cells. Oxidative stress also enhanced HAI-1 expression. Promoter analyses of the human HAI-1/spint-1 gene revealed overlapping binding site for Egr-1-3 and Sp1 near the transcription start site as the key domain for HAI-1/spint-1 transcription. This site was also critical in both hypoxic- and oxidative stress-induced HAI-1 upregulation. In fact, in vivo immunohistochemical studies indicated that areas with HAI-1 upregulation tended to express markers associated with hypoxia and oxidative stress. These observations suggest that the tissue microenvironment regulates the cell surface expression of HAI-1, and thereby may regulate proteolysis and processing of bioactive molecules on the cellular surface.

Roles of Kunitz domains in the anti-invasive effect of hepatocyte growth factor activator inhibitor type 1 in human glioblastoma cells

Hepatocyte growth factor activator inhibitor type 1 (HAI-1) is a membrane-bound serine proteinase inhibitor having two extracellular Kunitz-type proteinase inhibitor domains (KD) namely KD-1 and KD-2. It efficiently inhibits hepatocyte growth factor activator, matriptase, hepsin, prostasin and trypsin. We have previously reported that the expression of HAI-1 suppresses the in vitro invasive capability of human glioblastoma cells. In this study we examined the role of each KD in the anti-invasive effect of HAI-1. Engineered over-expression of the mature membrane-form HAI-1 suppressed in vitro fibrin gel invasion of two human glioblastoma cell lines, U251 and YKG-1. The migratory activity on type IV collagen was also suppressed by the HAI-1 expression. These effects were not affected by the deletion of intracytoplasmic domain of HAI-1. A truncated secreted form of HAI-1 also suppressed in vitro invasion of the cells, indicating that the extracellular portion of HAI-1 was responsible for the anti-invasive effect. To determine the roles of each KD in the anti-invasive effect of HAI-1 in vitro, we constructed expression plasmids for HAI-1 with or without mutation at the P1 position of the reactive site of each KD. The results revealed that the proteinase inhibitor activity of N-terminal KD (KD-1) is responsible for the anti-invasion effect of HAI-1.

DNA profiling of primary serous ovarian and fallopian tube carcinomas with array comparative genomic hybridization and multiplex ligation-dependent probe amplification

Primary serous ovarian carcinoma (OVCA) and serous Fallopian tube carcinoma (FTC), both belonging to the BRCA-linked tumour spectrum, share many properties and are treated similarly. However, a detailed molecular comparison has been lacking. We hypothesized that comparative genomic studies of serous OVCAs and FTCs should point to gene regions critically involved in their tumorigenesis. Array comparative genomic hybridization (array CGH) analysis indicated that serous OVCAs and serous FTCs displayed common but also more distinctive patterns of recurrent changes. Targeted gene identification using a dedicated multiplex ligation-dependent probe amplification (MLPA) probe set directly identified EIF2C2 on 8q as a potentially important driver gene. Other previously unappreciated gained/amplified genes included PSMB4 on 1q, MTSS1 on 8q, TEAD4 and TSPAN9 on 12p, and BCAS4 on 20q. SPINT2 and ACTN4 on 19q were predominantly found in FTCs. Gains/amplifications of CCNE1 and MYC, often in conjunction with changes in genes of the AKT pathway, EVI1 and PTK2, seemed to be involved at earlier stages, whereas changes of ERBB2 were associated with advanced stages. The only BRCA1-mutated FTC shared common denominators with the sporadic tumours. In conclusion, the data suggest that serous OVCAs and FTCs, although related, exhibit differences in genomic profiles. In addition to known pathways, new genes/pathways are likely to be involved, with changes in an miRNA-associated gene, EIF2C2, as one important new feature. Dedicated MLPA sets constitute potentially important tools for differential diagnosis and may provide footholds for tailored therapy.

Regulation of hepatocyte growth factor activator inhibitor 2 by hypoxia in breast cancer

PURPOSE

To examine the in vitro regulation of hepatocyte growth factor activator inhibitor type 2 (HAI-2) in breast cancer cells and the in vivo predictive role for the efficacy of chemoendocrine primary therapy in patients with breast cancer.

MATERIALS AND METHODS

HAI-2 regulation was studied in a panel of breast cancer cell lines comparing normoxia to hypoxia. The effect of HIF-1alpha RNAi on HAI-2 expression was evaluated in these cells. HAI-2 was examined in breast cancer using in situ hybridization and immunohistochemistry. The HAI-2 predictive role was assessed in T(2-4) N(0-1) breast cancers (n = 177) enrolled in a neoadjuvant randomized trial comparing epirubicin versus epirubicin + tamoxifen.

RESULTS

HAI-2 mRNA and protein were regulated by hypoxia in the c-erbB2-positive cell lines, SKBR3 and BT474, and controlled by HIF-1alpha in these cells. Immunohistochemistry confirmed this profile with high expression of HAI-2 in c-erbB2-positive breast cancer. HAI-2 was correlated with T status (P < 0.004), node involvement (P = 0.01), and c-erbB2 expression (P = 0.05). HAI-2 also correlated with hypoxia markers such as carbonic anhydrase IX expression (P = 0.01) and HIF-1alpha. Additionally, high levels of HAI-2 were a significant predictor for poor clinical complete response to preoperative epirubicin in univariate (P = 0.01) and multivariate analyses (P = 0.016). No correlation with disease-free survival and survival was observed.

CONCLUSION

HAI-2 expression in breast cancer correlated with tumor aggressiveness in vivo. It is a HIF target in c-erbB2-positive cells and it is an independent negative predictive factor of efficacy of anthracycline therapy. The interaction of HAI-2 with the hepatocyte growth factor activation pathway may be a useful site for therapeutic intervention.

Expression of hepatocyte growth factor activator inhibitor type 1 in endothelial cells

Hepatocyte growth factor activator inhibitor type 1 (HAI-1) is an integral membrane Kunitz-type serine proteinase inhibitor initially identified as a potent inhibitor of hepatocyte growth factor activator (HGFA). HGFA is a serum proteinase that is critically involved in the activation of hepatocyte growth factor/scatter factor (HGF/SF) in injured tissue. Previous studies have shown that HAI-1 is expressed on the basolateral surface of various epithelial cells. In this study, we analyzed the expression of HAI-1 in human endothelial cells. Immunohistochemically, HAI-1 protein was observed in the endothelial cells of capillaries, venules and lymph vessels. On the other hand, arterial endothelial cells were poorly stained for HAI-1. Mesothelial cells on the serous surface were also positively immunostained. The endothelial expression of HAI-1 was also examined in cultured human endothelial cells of various origins, such as umbilical vein, microvessels and aorta. Notably, in accordance with the results of immunohistochemistry, HAI-1 mRNA and protein levels were high in the endothelial cells derived from umbilical vein and were hardly detectable in those derived from aorta. A low but distinct level of HAI-1 expression was also observed in endothelial cells from microvessels. As these HAI-1-positive endothelial cells also expressed MET tyrosine kinase, the specific receptor of HGF/SF, it is conceivable that HAI-1 might have an important regulatory role in the HGF/SF-MET signaling axis of endothelial cells, which could be involved in the process of angiogenesis.

Hepatocyte growth factor activator inhibitor-1 (HAI-1) is essential for the integrity of basement membranes in the developing placental labyrinth

Hepatocyte growth factor activator inhibitor-1 (HAI-1) is a membrane-associated Kunitz-type serine protease inhibitor that regulates cell surface and extracellular serine proteases involved in tissue remodeling and tumorigenesis, such as HGFA, matriptase, prostasin and hepsin. We generated HAI-1 deficient mice, which died in utero due to placental defects. The HAI-1(-/-) placental labyrinth exhibited a complete failure of vascularization and a compact morphology of the trophoblast layer. Immunofluorescent staining of collagen IV and laminin and electron microscopy analysis revealed that this aberrant labyrinth architecture was associated with disrupted basement membranes located at the interface of chorionic trophoblasts and allantoic mesoderm. Unlike the placental labyrinth, basement membranes and vasculogenesis were normal in embryo and yolk sac. Therefore, basement membrane defects appear to be the underlying cause for the greatly impaired vascularization and trophoblast branching in HAI-1(-/-) placentas. In wild-type placentas, the expression of matriptase and prostasin co-localized with their physiological inhibitor HAI-1 to the labyrinthine trophoblast cells in proximity to basement membranes. In HAI-1(-/-) placentas, both the localization and expression of the two proteases remained unchanged, implying uncontrolled proteolytic activities of the two enzymes. Our study demonstrates the important role of HAI-1 in maintaining the integrity of basement membrane most likely by regulating extracellular proteolytic activities during placental development.

The ratio of Matriptase/HAI-1 mRNA is higher in colorectal cancer adenomas and carcinomas than corresponding tissue from control individuals

Background

It has recently been shown that overexpression of the serine protease, matriptase, in transgenic mice causes a dramatically increased frequency of carcinoma formation. Overexpression of HAI-1 and matriptase together changed the frequency of carcinoma formation to normal. This suggests that the ratio of matriptase to HAI-1 influences the malignant progression. The aim of this study has been to determine the ratio of matriptase to HAI-1 mRNA expression in affected and normal tissue from individuals with colorectal cancer adenomas and carcinomas as well as in healthy individuals, in order to determine at which stages a dysregulated ratio of matriptase/HAI-1 mRNA is present during carcinogenesis.

Methods

Using quantitative RT-PCR, we have determined the mRNA levels for matriptase and HAI-1 in colorectal cancer tissue (n = 9), severe dysplasia (n = 15), mild/moderate dysplasia (n = 21) and in normal tissue from the same individuals. In addition, corresponding tissue was examined from healthy volunteers (n = 10). Matriptase and HAI-1 mRNA levels were normalized to β-actin.

Results

Matriptase mRNA level was lower in carcinomas compared to normal tissue from healthy individuals (p < 0.01). In accordance with this, the matriptase mRNA level was also lower in adenomas/carcinomas combined as compared to their adjacent normal tissue (p < 0.01). HAI-1 mRNA levels in both normal and affected tissue from individuals with severe dysplasia or carcinomas and in affected tissue with mild/moderate dysplasia were all significantly lower than mRNA levels observed in corresponding tissue from healthy control individuals. HAI-1 mRNA was lower in carcinomas as compared to normal tissue from healthy individuals (p < 0.001). HAI-1 mRNA levels were significantly lower in tissue displaying mild/moderate (p < 0.001) and severe (p < 0.01) dysplasia compared to normal tissue from the same patients. Both adenomas and carcinomas displayed a significantly different matriptase/HAI-1 mRNA ratio than corresponding normal tissue from healthy control individuals (p < 0.05). In addition statistically significant difference (p < 0.001) could be observed between mild/moderate and severe adenomas and their adjacent normal tissue.

Conclusion

Our results show that dysregulation of the matriptase/HAI-1 mRNA ratio occurs early during carcinogenesis. Future studies are required to clarify whether the dysregulated matriptase/HAI-1 ratio was causing the malignant progression or is a consequence of the same.

A novel biomarker for staging human prostate adenocarcinoma: overexpression of matriptase with concomitant loss of its inhibitor, hepatocyte growth factor activator inhibitor-1

BACKGROUND

Matriptase, a type II transmembrane serine protease is involved in angiogenesis, degradation of extracellular matrix, and in the progression of some epithelial cancers. Here, we establish the clinical significance of matriptase and its inhibitor, hepatocyte growth factor activator inhibitor-1 (HAI-1), during the progression of human prostate cancer (CaP).

METHODS

The expression patterns of matriptase and HAI-1 were determined in primary cultures of normal human prostate epithelial (NHPE) cells, human CaP cells LNCaP, DU-145, CWR22Rnu1, and PC-3, and in tissue samples of 172 patients with normal prostate, benign prostatic hyperplasia (BPH), prostatic intraepithelial neoplasia (PIN), and adenocarcinoma of different tumor grades.

RESULTS

The protein and mRNA levels of matriptase were significantly higher in all carcinoma cells as compared with NHPE cells. Conversely, all CaP cells exhibited a reduced expression of HAI-1 as compared with NHPE cells. A progressive increase in the protein levels of matriptase was observed with increasing tumor grade in CaP specimens as compared with normal and BPH tissue specimens. Tissue samples of normal prostate exhibited a high constitutive protein level of HAI-1 compared with BPH and low-grade cancer with a progressive loss with increasing tumor grade.

CONCLUSION

The increased expression of matriptase and loss of HAI-1 may be an important event during the progression of CaP in humans. We suggest that the ratio of these two gene products may serve as a promising biomarker for CaP progression and a potential marker for establishing the efficacy of therapeutic and chemopreventive interventions.

Serum hepatocyte growth factor activator inhibitor type I (HAI-I) and type 2 (HAI-2) in prostate cancer

BACKGROUND

Hepatocyte growth factor activator inhibitor type 1 (HAI-1) and type 2 (HAI-2) are Kunitz-type serine protease inhibitors for hepatocyte growth factor activator (HGFA). We attempted to clarify whether serum levels of HAI-1 and HAI-2 could be a useful marker in patients with prostate cancer.

METHODS

Serum levels of HAI-1 and HAI-2 were measured by enzyme-linked immunosorbent assay in 27 patients with benign prostatic hyperplasia (BPH) and 118 patients with prostate cancer.

RESULTS

The mean serum levels of HAI-1 in patients with prostate cancer were significantly higher than those in patients with BPH. Furthermore, the serum HAI-1 levels in patients with distant metastasis and hormone resistant prostate cancer were significantly elevated compared with those in patients with organ-confined diseases. There were no significant differences in serum HAI-2 levels among prostate cancer subgroups according to clinical stage. Significantly elevated levels of HAI-1 were detected in 38 patients with prostate cancer before any treatment.

CONCLUSIONS

HAI-1 may be a potential tumor marker for prostate cancer. Further studies in large groups of patients are needed to define the clinical value of HAI-1.

Identification of antibodies against HAI-1 and integrin alpha6beta4 as immunohistochemical markers of human villous cytotrophoblast

Syncytiotrophoblast and invasive extravillous trophoblast arise from a common stem cell, namely villous cytotrophoblast, but have very different characteristics. The study of the differentiation process relies on the availability of suitable markers for these different cell types of developing placenta. In this work, we have produced monoclonal antibodies that are specific to human villous cytotrophoblast. Monoclonal antibody (MAb) MG2 was specific to villous cytotrophoblast across gestation, and recognizes hepatocyte growth factor activator inhibitor type 1. MAb MD10 stained villous cytotrophoblast across gestation and also some endothelial cells, particularly in the second or third trimester. MAb MD10 recognizes human integrin alpha6beta4. As a test for specificity, the novel MAbs were also used for staining of frozen tissue from human colon carcinoma. The results show that the two antibodies can be used as tools to study human villous cytotrophoblasts and also human tumors. The MG2 antibody seems most specific and promising for the study of various aspects of human villous cytotrophoblast.

Expression of serine protease SNC19/matriptase and its inhibitor hepatocyte growth factor activator inhibitor type 1 in normal and malignant tissues of gastrointestinal tract

AIM: To provide the expression profile of serine protease SNC19/matriptase and its inhibitor hepatocyte growth factor activator inhibitor type 1 (HAI-1) in normal and malignant tissues of gastrointestinal tract at mRNA level for further study on their correlations with tumor progression and metastasis.

METHODS: Total RNAs were prepared from 37 samples of colorectal cancer tissues, 40 samples of gastric cancer tissues, and their adjacent normal tissues. The expression of SNC19/matriptase and HAI-1 in these samples was detected by real-time fluorescent quantitative PCR using glyceraldehyde-3-phosphate dehydrogenase as internal standard, and the clinical significance for the correlation with clinicopathological parameters was evaluated.

RESULTS: In gastric cancer tissues the expression of HAI-1 and SNC19/matriptase was significantly lower than that in the corresponding adjacent normal tissues (Z = -3.280, P = 0.006; Z = -4.651, P = 0.000). HAI-1:SNC19/matriptase ratio showed no difference between normal and malignant tissues (P>0.05). Analysis of clinicopathological parameters showed decreased expression of HAI-1 and HAI-1:SNC19/matriptase ratio associated with stage III/IV gastric tumors as compared to stage I/II ones (Z = -2.140, P = 0.031; Z = -2.155, P = 0.031), and with lymph node-positive gastric cancer tissues as compared to lymph node-negative ones (Z = -2.081, P = 0.036; Z = -2.686, P = 0.006). The expression of SNC19/matriptase had no relationship with stages and lymph node metastasis (P>0.05). The expression of HAI-1 and HAI-1:SNC19/matriptase ratio increased in well-differentiated gastric cancer tissues, but there was no statistical significance (P>0.05). The difference of SNC19/matriptase expression was not significant in gastric cancer tissues of different histological differentiation status (P>0.05). In colorectal cancer tissues, the expression of HAI-1 and SNC19/matriptase was also markedly lower than that in their adjacent normal tissues (Z = -3.100, P = 0.002; Z = -2.731, P = 0.006), whereas HAI-1:SNC19/matriptase ratio showed no difference. Decreased expression of HAI-1 was associated with increased invasive depth and lymph node metastasis, but there was no statistical significance (P>0.05). The difference of SNC19/matriptase expression and HAI-1:SNC19/matriptase ratio was not significant in different stages and different lymph node metastasis status (P>0.05). The expression of SNC19/matriptase, HAI-1 or HAI-1:SNC19/matriptase ratio showed no difference in colorectal cancer tissues of different histological differentiation status (P>0.05).

CONCLUSION: The expressions of SNC19/matriptase and its inhibitor HAI-1 are decreased in gastrointestinal cancer tissues compared to their normal counterparts, and the decreased expression of HAI-1 may correlate with invasion and lymph node metastasis. The possible mechanisms involved need to be further investigated.

Diverse roles of hepatocyte growth factor activator inhibitor type 1 (HAI-1) in the growth of glioblastoma cells in vivo

Hepatocyte growth factor activator inhibitor type-1 (HAI-1) is an integral-membrane proteinase inhibitor. In this study, we examined the effects of HAI-1 on human glioblastoma cells. Two glioblastoma cell lines (YKG-1, U251) were stably transfected with expression plasmid harboring mature membrane-form or truncated secreted-form HAI-1. Culture characteristics were not altered by the expression of HAI-1, whereas in vitro invasiveness of U251 was suppressed. On the other hand, the expression of membrane-form HAI-1 resulted in significantly enhanced tumorigenicity of both cell lines in vivo. In contrast, secreted-form HAI-1 did not promote the tumorigenicity. These results suggest that HAI-1 may play complex roles in progression of glioblastoma cells, and membrane-form HAI-1 may mediate an undefined important signaling in the cells.

Hepatocyte growth factor activator inhibitor type 1 (HAI-1) is required for branching morphogenesis in the chorioallantoic placenta

Hepatocyte growth factor activator inhibitor type 1 (HAI-1) is a membrane-associated Kunitz-type serine proteinase inhibitor that was initially identified as a potent inhibitor of hepatocyte growth factor activator. HAI-1 is also a cognate inhibitor of matriptase, a membrane-associated serine proteinase. HAI-1 is expressed predominantly in epithelial cells in the human body. Its mRNA is also abundant in human placenta, with HAI-1 specifically expressed by villous cytotrophoblasts. In order to address the precise roles of HAI-1 in vivo, we generated HAI-1 mutant mice by homozygous recombination. Heterozygous HAI-1+/- mice underwent normal organ development. However, homozygous HAI-1-/- mice experienced embryonic lethality which became evident at embryonic day 10.5 postcoitum (E10.5). As early as E9.5, HAI-1-/- embryos showed growth retardation that did not reflect impaired cell proliferation but resulted instead from failed placental development and function. Histological analysis revealed severely impaired formation of the labyrinth layer, in contrast all other placental layers, such as the spongiotrophoblast layer and giant cell layer, which were formed. Our results indicate that mouse HAI-1 is essential for branching morphogenesis in the chorioallantoic placenta and lack of HAI-1 function may result in placental failure.