Genome-wide association studies in the Japanese population identified genetic loci and target gene associated with epidermal turnover

The epidermis is an essential organ for life by retaining water and as a protective barrier. The epidermis is maintained through metabolism, in which basal cells produced from epidermal stem cells differentiate into spinous cells, granular cells and corneocytes, and are finally shed from the epidermal surface. This is epidermal turnover, and with aging, there is a decline in epidermis function. Other factors that may affect epidermal turnover include ultraviolet damage and genetic factors. These genetic factors are of particular interest as little is known. Although recent skin-focused genome-wide association studies (GWAS) have been conducted, the genetic regions associated with epidermal turnover are almost uninvestigated. Therefore, we conducted a GWAS on epidermal turnover in the Japanese population, using the corneocyte area, which correlates to the rate of epidermal turnover, as an indicator. As a result, rs2278431 (p = 1.29 × 10-7 ) in 19q13.2 was associated with corneocyte size. Furthermore, eQTL analysis suggested that rs2278431 was related to the SPINT2 gene. In addition, SPINT2 knockdown studies using epidermal keratinocytes revealed that SPINT2 is involved in keratinocyte proliferation and in corneocyte size regulation in reconstructed epidermis. These results suggest that rs2278431 is involved in the expression of SPINT2 and affects epidermal turnover.

Proteases and HPV-Induced Carcinogenesis

Simple Summary

Human papillomavirus (HPV) infection is a sexually transmitted disease with high prevalence worldwide. Although most HPV infections do not lead to cancer, some HPV types are correlated with the majority of cervical cancers, and with some anogenital and oropharyngeal cancers. Moreover, enzymes known as proteases play an essential role in the pathogenic process in HPV-induced carcinogenesis. This review highlights the role of proteases and recent epidemiological data regarding HPV-dependent carcinogenesis.

Abstract

Persistent infection with Human papillomavirus (HPV) is the main etiologic factor for pre-malignant and malignant cervical lesions. Moreover, HPV is also associated with oropharynx and other anogenital carcinomas. Cancer-causing HPV viruses classified as group 1 carcinogens include 12 HPV types, with HPV 16 and 18 being the most prevalent. High-risk HPVs express two oncoproteins, E6 and E7, the products of which are responsible for the inhibition of p53 and pRB proteins, respectively, in human keratinocytes and cellular immortalization. p53 and pRB are pleiotropic proteins that regulate the activity of several signaling pathways and gene expression. Among the important factors that are augmented in HPV-mediated carcinogenesis, proteases not only control processes involved in cellular carcinogenesis but also control the microenvironment. For instance, genetic polymorphisms of matrix metalloproteinase 1 (MMP-1) are associated with carcinoma invasiveness. Similarly, the serine protease inhibitors hepatocyte growth factor activator inhibitor-1 (HAI-1) and -2 (HAI-2) have been identified as prognostic markers for HPV-dependent cervical carcinomas. This review highlights the most crucial mechanisms involved in HPV-dependent carcinogenesis, and includes a section on the proteolytic cascades that are important for the progression of this disease and their impact on patient health, treatment, and survival.

The Kunitz-type serine protease inhibitor Spint2 is required for cellular cohesion, coordinated cell migration and cell survival during zebrafish hatching gland development

We have previously shown that the Kunitz-type serine protease inhibitor Spint1a, also named Hai1a, is required in the zebrafish embryonic epidermis to restrict the activity of the type II transmembrane serine protease (TTSP) Matriptase1a/St14a, thereby ensuring epidermal homeostasis. A closely related Kunitz-type inhibitor is Spint2/Hai2, which in mammals plays multiple developmental roles that are either redundant or non-redundant with those of Spint1. However, the molecular bases for these non-redundancies are not fully understood. Here, we study spint2 during zebrafish development. It is co-expressed with spint1a in multiple embryonic epithelia, including the outer/peridermal layer of the epidermis. However, unlike spint1a, spint2 expression is absent from the basal epidermal layer but present in hatching gland cells. Hatching gland cells derive from the mesendodermal prechordal plate, from where they undergo a thus far undescribed transit into, and coordinated sheet migration within, the interspace between the outer and basal layer of the epidermis to reach their final destination on the yolk sac. Hatching gland cells usually survive their degranulation that drives embryo hatching but die several days later. In spint2 mutants, cohesion among hatching gland cells and their collective intra-epidermal migration are disturbed, leading to a discontinuous organization of the gland. In addition, cells undergo precocious cell death before degranulation, so that embryos fail to hatch. Chimera analyses show that Spint2 is required in hatching gland cells, but not in the overlying periderm, their potential migration and adhesion substrate. Spint2 acts independently of all tested Matriptases, Prostasins and other described Spint1 and Spint2 mediators. However, it displays a tight genetic interaction with and acts at least partly via the cell-cell adhesion protein E-cadherin, promoting both hatching gland cell cohesiveness and survival, in line with formerly reported effects of E-cadherin during morphogenesis and cell death suppression. In contrast, no such genetic interaction was observed between Spint2 and the cell-cell adhesion molecule EpCAM, which instead interacts with Spint1a. Our data shed new light onto the mechanisms of hatching gland morphogenesis and hatching gland cell survival. In addition, they reveal developmental roles of Spint2 that are strikingly different from those of Spint1, most likely due to differences in the expression patterns and relevant target proteins.

A five-mRNA signature associated with post-translational modifications can better predict recurrence and survival in cervical cancer

High mortality of patients with cervical cancer (CC) stresses the imperative of prognostic biomarkers for CC patients. Additionally, the vital status of post‐translational modifications (PTMs) in the progression of cancers has been reported by numerous researches. Therefore, the purpose of this research was to dig a prognostic signature correlated with PTMs for CC. We built a five‐mRNA (GALNTL6, ARSE, DPAGT1, GANAB and FURIN) prognostic signature associated with PTMs to predict both disease‐free survival (DFS) (hazard ratio [HR] = 3.967, 95% CI = 1.985‐7.927; P < .001) and overall survival (HR = 2.092, 95% CI = 1.138‐3.847; P = .018) for CC using data from The Cancer Genome Atlas database. Then, the robustness of the signature was validated using GSE44001 and the Human Protein Atlas (HPA) database. CIBERSORT algorithm analysis displayed that activated CD4 memory T cell was also an independent indicator for DFS (HR = 0.426, 95% CI = 0.186‐0.978; P = .044) which could add additional prognostic value to the signature. Collectively, the PTM‐related signature and activated CD4 memory T cell can provide new avenues for the prognostic predication of CC. These findings give further insights into effective treatment strategies for CC, providing opportunities for further experimental and clinical validations.

Cell surface-anchored serine proteases in cancer progression and metastasis

Over the last two decades, a novel subgroup of serine proteases, the cell surface-anchored serine proteases, has emerged as an important component of the human degradome, and several members have garnered significant attention for their roles in cancer progression and metastasis. A large body of literature describes that cell surface-anchored serine proteases are deregulated in cancer and that they contribute to both tumor formation and metastasis through diverse molecular mechanisms. The loss of precise regulation of cell surface-anchored serine protease expression and/or catalytic activity may be contributing to the etiology of several cancer types. There is therefore a strong impetus to understand the events that lead to deregulation at the gene and protein levels, how these precipitate in various stages of tumorigenesis, and whether targeting of selected proteases can lead to novel cancer intervention strategies. This review summarizes current knowledge about cell surface-anchored serine proteases and their role in cancer based on biochemical characterization, cell culture-based studies, expression studies, and in vivo experiments. Efforts to develop inhibitors to target cell surface-anchored serine proteases in cancer therapy will also be summarized.

Loss of SPINT2 expression frequently occurs in glioma, leading to increased growth and invasion via MMP2

PURPOSE

High-grade gliomas (HGG) remain one of the most aggressive tumors, which is primarily due to its diffuse infiltrative nature. Serine proteases and metalloproteases are known to play key roles in cellular migration and invasion mechanisms. SPINT2, also known as HAI-2, is an important serine protease inhibitor that can affect MET signaling. SPINT2 has been found to be frequently downregulated in various tumors, whereby hypermethylation of its promoter appears to serve as a common mechanism. Here, we assessed the clinical relevance of SPINT2 expression and promoter hypermethylation in pediatric and adult HGG and explored its functional role.

METHODS

A series of 371 adult and 77 pediatric primary HGG samples was assessed for SPINT2 protein expression (immunohistochemistry) and promoter methylation (methylation-specific PCR) patterns. After SPINT2 knockdown and knock-in in adult and pediatric HGG cell lines, a variety of in vitro assays was carried out to determine the role of SPINT2 in glioma cell viability and invasion, as well as their mechanistic associations with metalloprotease activities.

RESULTS

We found that SPINT2 protein expression was frequently absent in adult (85.3%) and pediatric (100%) HGG samples. The SPINT2 gene promoter was found to be hypermethylated in approximately half of both adult and pediatric gliomas. Through functional assays we revealed a suppressor activity of SPINT2 in glioma cell proliferation and viability, as well as in their migration and invasion. These functions appear to be mediated in part by MMP2 expression and activity.

CONCLUSIONS

We conclude that dysregulation of SPINT2 is a common event in both pediatric and adult HGG, in which SPINT2 may act as a tumor suppressor.

STYK1 promotes tumor growth and metastasis by reducing SPINT2/HAI-2 expression in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the leading cause of cancer deaths worldwide. However, the molecular mechanisms underlying NSCLC progression remains not fully understood. In this study, 347 patients with complete clinicopathologic characteristics who underwent NSCLC surgery were recruited for the investigation. We verified that elevated serine threonine tyrosine kinase 1 (STYK1) or decreased serine peptidase inhibitor Kunitz type 2 (SPINT2/HAI-2) expression significantly correlated with poor prognosis, tumor invasion, and metastasis of NSCLC patients. STYK1 overexpression promoted NSCLC cells proliferation, migration, and invasion. STYK1 also induced epithelial–mesenchymal transition by E-cadherin downregulation and Snail upregulation. Moreover, RNA-seq, quantitative polymerase chain reaction (qRT-PCR), and western blot analyses confirmed that STYK1 overexpression significantly decreased the SPINT2 level in NSCLC cells, and SPINT2 overexpression obviously reversed STYK1-mediated NSCLC progression both in vitro and in vivo. Further survival analyses showed that NSCLC patients with high STYK1 level and low SPINT2 level had the worst prognosis and survival. These results indicated that STYK1 facilitated NSCLC progression via reducing SPINT2 expression. Therefore, targeting STYK1 and SPINT2 may be a novel therapeutic strategy for NSCLC.

Study on the methylation status of SPINT2 gene and its expression in cervical carcinoma

BACKGROUND

Cervical cancer is one of the malignant tumors which seriously threaten the women health worldwide. SPINT2 is an endogenous inhibitor of hepatocyte growth factor activator and down regulated or even silenced in many human malignant tumors.

OBJECTIVE

This study was performed to explore the promoter methylation status of SPINT2 gene and the effect on its expression in cervical carcinoma.

METHODS

HPV-positive and -negative cervical cancer cell lines, 50 cases of cervical carcinoma tissues, and 20 cases of normal cervical tissues were used for this study. The methylation status of promoter and the first exon of SPINT2 gene were analyzed. The expression of SPINT2 was analyzed by qRT-PCR.

RESULTS

HPV E6/E7 infection affects SPINT2 methylation rate in cell lines. SPINT2 methylation rate of HT-3E6/E7 was 8.8%, while the methylation rate of SPINT2 in HT-3 was 0%. In cervical tissues, the methylation rate of SPINT2 in cervical cancers was 54%, while the methylation rate of SPINT2 in normal cervical samples was 25%. As for cervical cancers, the methylation rate of SPINT2 gene was higher in grade 3 than those of grade 2.

CONCLUSIONS

The expression of SPINT2 gene is regulated by its methylation status, and the methylation status of SPINT2 is altered by HPV infection. The aberrant methylation status of SPINT2 gene may play an important role in the development of cervical cancer.

Serine peptidase inhibitor Kunitz type 2 (SPINT2) in cancer development and progression

Understanding the molecular basis and mechanisms involved in neoplastic transformation and progression is important for the development of novel selective target therapeutic strategies. Hepatocyte growth factor (HGF)/c-MET signaling plays an important role in cell proliferation, survival, migration and motility of cancer cells. Serine peptidase inhibitor Kunitz type 2 (SPINT2) binds to and inactivates the HGF activator (HGFA), behaving as an HGFA inhibitor (HAI) and impairing the conversion of pro-HGF into bioactive HGF. The scope of the present review is to recapitulate and review the evidence of SPINT2 participation in cancer development and progression, exploring the clinical, biological and functional descriptions of the involvement of this protein in diverse neoplasias. Most studies are in agreement as to the belief that, in a large range of human cancers, the SPINT2 gene promoter is frequently methylated, resulting in the epigenetic silence of this gene. Functional assays indicate that SPINT2 reactivation ameliorates the malignant phenotype, specifically reducing cell viability, migration and invasion in diverse cancer cell lines. In sum, the SPINT2 gene is epigenetically silenced or downregulated in human cancers, altering the balance of HGF activation/inhibition ratio, which contributes to cancer development and progression.

Hepatocyte growth factor activator inhibitor type-2 (HAI-2)/SPINT2 contributes to invasive growth of oral squamous cell carcinoma cells

Hepatocyte growth factor activator inhibitor (HAI)-1/SPINT1 and HAI-2/SPINT2 are membrane-anchored protease inhibitors having homologous Kunitz-type inhibitor domains. They regulate membrane-anchored serine proteases, such as matriptase and prostasin. Whereas HAI-1 suppresses the neoplastic progression of keratinocytes to invasive squamous cell carcinoma (SCC) through matriptase inhibition, the role of HAI-2 in keratinocytes is poorly understood. In vitro homozygous knockout of the SPINT2 gene suppressed the proliferation of two oral SCC (OSCC) lines (SAS and HSC3) but not the growth of a non-tumorigenic keratinocyte line (HaCaT). Reversion of HAI-2 abrogated the growth suppression. Matrigel invasion of both OSCC lines was also suppressed by the loss of HAI-2. The levels of prostasin protein were markedly increased in HAI-2-deficient cells, and knockdown of prostasin alleviated the HAI-2 loss-induced suppression of OSCC cell invasion. Therefore, HAI-2 has a pro-invasive role in OSCC cells through suppression of prostasin. In surgically resected OSCC tissues, HAI-2 immunoreactivity increased along with neoplastic progression, showing intense immunoreactivities in invasive OSCC cells. In summary, HAI-2 is required for invasive growth of OSCC cells and may contribute to OSCC progression.

The Kunitz Domain I of Hepatocyte Growth Factor Activator Inhibitor-2 Inhibits Matriptase Activity and Invasive Ability of Human Prostate Cancer Cells

Dysregulation of pericellular proteolysis is often required for tumor invasion and cancer progression. It has been shown that down-regulation of hepatocyte growth factor activator inhibitor-2 (HAI-2) results in activation of matriptase (a membrane-anchored serine protease), human prostate cancer cell motility and tumor growth. In this study, we further characterized if HAI-2 was a cognate inhibitor for matriptase and identified which Kunitz domain of HAI-2 was required for inhibiting matriptase and human prostate cancer cell motility. Our results show that HAI-2 overexpression suppressed matriptase-induced prostate cancer cell motility. We demonstrate that HAI-2 interacts with matriptase on cell surface and inhibits matriptase proteolytic activity. Moreover, cellular HAI-2 harnesses its Kunitz domain 1 (KD1) to inhibit matriptase activation and prostate cancer cell motility although recombinant KD1 and KD2 of HAI-2 both show an inhibitory activity and interaction with matriptase protease domain. The results together indicate that HAI-2 is a cognate inhibitor of matriptase, and KD1 of HAI-2 plays a major role in the inhibition of cellular matritptase activation as well as human prostate cancer invasion.

The crystal structure of a multidomain protease inhibitor (HAI-1) reveals the mechanism of its auto-inhibition

Hepatocyte growth factor activator inhibitor 1 (HAI-1) is a membrane-bound multidomain protein essential to the integrity of the basement membrane during placental development and is also important in maintaining postnatal homeostasis in many tissues. HAI-1 is a Kunitz-type serine protease inhibitor, and soluble fragments of HAI-1 with variable lengths have been identified in vivo The full-length extracellular portion of HAI-1 (sHAI-1) shows weaker inhibitory activity toward target proteases than the smaller fragments, suggesting auto-inhibition of HAI-1. However, this possible regulatory mechanism has not yet been evaluated. Here, we solved the crystal structure of sHAI-1 and determined the solution structure by small-angle X-ray scattering. These structural analyses revealed that, despite the presence of long linkers, sHAI-1 exists in a compact conformation in which sHAI-1 active sites in Kunitz domain 1 are sterically blocked by neighboring structural elements. We also found that in the presence of target proteases, sHAI-1 adopts an extended conformation that disables the auto-inhibition effect. Our results also reveal the roles of non-inhibitory domains of this multidomain protein and explain the low activity of the full-length protein. The structural insights gained here improve our understanding of the regulation of HAI-1 inhibitory activities and point to new approaches for better controlling these activities.

SPINT2 Deregulation in Prostate Carcinoma

SPINT2 is a tumor suppressor gene that inhibits proteases implicated in cancer progression, like HGFA, hepsin and matriptase. Loss of SPINT2 expression in tumors has been associated with gene promoter hypermethylation; however, little is known about the mechanisms of SPINT2 deregulation in prostate cancer (PCa). We aimed to analyze SPINT2 expression levels and understand the possible regulation by SPINT2 promoter hypermethylation in PCa. In a cohort of 57 cases including non-neoplastic and PCa tissues, SPINT2 expression and promoter methylation was analyzed by immunohistochemistry and methylation-specific PCR, respectively. Methylation status of the SPINT2 promoter was also evaluated by bisulfite sequencing and 5-aza-2'-deoxycytidine treatment. Oncomine and TCGA databases were used to perform in silico PCa analysis of SPINT2 mRNA and methylation levels. A reduction in SPINT2 expression levels from non-neoplastic to PCa tissues was observed; however, none of the cases exhibited SPINT2 promoter methylation. Both bisulfite sequencing and 5-aza demonstrated that SPINT2 promoter is not methylated in PCa cells. Bioinformatics approaches did not show downregulation of SPINT2 at the mRNA level and, in corroboration with our results, SPINT2 promoter region is reported to be unmethylated. Our study suggests an involvement of SPINT2 in PCa tumorigenesis, probably in association with a post-translational regulation of SPINT2.

Recent Progress and Advances in HGF/MET-Targeted Therapeutic Agents for Cancer Treatment

The hepatocyte growth factor (HGF): MET axis is a ligand-mediated receptor tyrosine kinase pathway that is involved in multiple cellular functions, including proliferation, survival, motility, and morphogenesis. Aberrancy in the HGF/MET pathway has been reported in multiple tumor types and is associated with tumor stage and prognosis. Thus, targeting the HGF/MET pathway has become a potential therapeutic strategy in oncology development in the last two decades. A number of novel therapeutic agents-either as therapeutic proteins or small molecules that target the HGF/MET pathway-have been tested in patients with different tumor types in clinical studies. In this review, recent progress in HGF/MET pathway-targeted therapy for cancer treatment, the therapeutic potential of HGF/MET-targeted agents, and challenges in the development of such agents will be discussed.

Matriptase promotes inflammatory cell accumulation and progression of established epidermal tumors

Deregulation of matriptase is a consistent feature of human epithelial cancers and correlates with poor disease outcome. We have previously shown that matriptase promotes multi-stage squamous cell carcinogenesis in transgenic mice through dual activation of pro-hepatocyte growth factor-cMet-Akt-mTor proliferation/survival signaling and PAR-2-Gαi-NFκB inflammatory signaling. Matriptase was congenitally and constitutively deregulated in our prior studies, and therefore it was unclear if aberrant matriptase signaling supports only initiation of tumor formation or if it is also critical for the progression of established tumors. To determine this, we here have generated triple-transgenic mice with constitutive deregulation of matriptase and simultaneous inducible expression of the cognate matriptase inhibitor, hepatocyte growth factor inhibitor (HAI)-2. As expected, constitutive expression of HAI-2 suppressed the formation of matriptase-dependent tumors in 7,12-Dimethylbenz(a)anthracene-treated mouse skin. Interestingly, however, the induction of HAI-2 expression in already established tumors markedly impaired malignant progression and caused regression of individual tumors. Tumor regression correlated with reduced accumulation of tumor-associated inflammatory cells, likely caused by diminished expression of pro-tumorigenic inflammatory cytokines. The data suggest that matriptase-dependent signaling may be a therapeutic target for both squamous cell carcinoma chemoprevention and for the treatment of established tumors.

Epigenetic inactivation of SPINT2 is associated with tumor suppressive function in esophageal squamous cell carcinoma

Hepatocyte growth factor activator inhibitor type 2 (SPINT2), a Kunitz-type serine proteinase inhibitor, has been identified as a putative tumor suppressor gene silenced by promoter methylation. We aimed to investigate whether SPINT2 might act as an esophageal squamous cell carcinoma (ESCC) tumor suppressor gene. Four ESCC cell lines, Fifty-two ESCC tissues and twenty-nine neighboring non-cancerous tissues were included in this study. The expression of SPINT2 was monitored by real time PCR. Bisulfite genomic sequencing and methylation-specific PCR were used to analyze methylation status. The effect of SPINT2 on cell proliferation and apoptosis in EC109 and EC9706 cells was observed by CCK-8 assay and flow cytometric analysis. We found that silencing of SPINT2 was associated with promoter methylation in ESCC cell lines. The densely methylated SPINT2 promoter region was confirmed by bisulfite genomic sequencing. Ectopic expression of SPINT2 inhibited cell proliferation through inducing cell apoptosis in vitro. Furthermore, methylation-specific PCR analysis revealed that SPINT2 promoter methylation was prominent in carcinoma tissues (52.08%) compared with neighboring non-cancerous tissues (22.58%). Kaplan-Meier analysis showed that patients with SPINT2 hypermethylation had shorter survival time. The tumor suppressor gene of SPINT2 is commonly silenced by promoter hypermethylation in human ESCC and SPINT2 hypermethylation is correlated with poor overall survival, implicating SPINT2 is an underlying prognostic marker for human ESCC.

The role of hepatocyte growth factor activator inhibitor (HAI)-1 and HAI-2 in endometrial cancer

Hepatocyte growth factor activator inhibitors (HAI-1 and HAI-2) are Kunitz-type serine protease inhibitors that have a broad inhibitory spectrum against serine proteases. This is the first study to investigate the role of HAI-1 and HAI-2 in endometrial cancer. We investigated the biological functions of HAI-1 and HAI-2 using KLE and HEC-251 endometrial cancer cell lines, thus HAI-1 and HAI-2 were examined in uterine normal endometrium, endometrial hyperplasia and cancer specimens by immunohistochemistry. HAI-1 and HAI-2 showed potential inhibitory effects on cell proliferation, migration and cellular invasion by reduction of matriptase and hepsin expression. This in turn led to an increase in the levels of E-cadherin and Slug, and a reduction in the levels of Vimentin, SIP1, Snail and Twist, and hence ER and PR signal transduction in endometrial cancer cells. The levels of HAI-1 and HAI-2 expression were significantly decreased in endometrial cancer specimens relative to the corresponding normal endometrium specimens. Low HAI-1 and HAI-2 expression was a significant predictor for a poor prognosis compared with high HAI-1 and HAI-2 expression. These findings indicate that HAI-1 and HAI-2 could be considered as therapeutic targets and used as favorable prognosis markers for endometrial cancer.

Hepatocyte growth factor activator (HGFA): pathophysiological functions in vivo

Hepatocyte growth factor activator (HGFA) is a serine protease initially identified as a potent activator of hepatocyte growth factor/scatter factor. Hepatocyte growth factor/scatter factor is known to be critically involved in tissue morphogenesis, regeneration, and tumor progression, via its receptor, MET. In vivo, HGFA also activates macrophage-stimulating protein, which has roles in macrophage recruitment and inflammatory processes, cellular survival and wound healing through its receptor, RON. Therefore, the pericellular activity of HGFA might be an important factor regulating the activities of these multifunctional cytokines in vivo. HGFA is secreted mainly by the liver, circulates in the plasma as a zymogen (pro-HGFA), and is activated in response to tissue injury, including tumor growth. In addition, local production of pro-HGFA by epithelial, stromal or tumor cells has been reported. Although the generation of HGFA-knockout mice revealed that the role played by HGFA in normal development and physiological settings can be compensated for by other protease systems, HGFA has important roles in regeneration and initial macrophage recruitment in injured tissue in vivo. Insufficient activity of HGFA results in impaired regeneration of severely damaged mucosal epithelium, and may contribute to the progression of fibrotic lung diseases. On the other hand, deregulated excess activity of HGFA may be involved in the progression of some types of cancer.