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

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.

KLK14 interactions with HAI-1 and HAI-2 serine protease inhibitors: A molecular dynamics and relative free-energy calculations study

Kallikrein 14 (KLK14) is a serine protease linked to several pathologies including prostate cancer and positively correlates with Gleason score. Though KLK14 functioning in cancer is poorly understood, it has been implicated in HGF/Met signaling, given that KLK14 proteolytically inhibits HGF activator-inhibitor 1 (HAI-1), which strongly inhibits pro-HGF activators, thereby contributing to tumor progression. In this work, KLK14 binding to either hepatocyte growth factor activator inhibitor type-1 (HAI-1) or type-2 (HAI-2) was essayed using homology modeling, molecular dynamic simulations and free-energy calculations through MM/PBSA and MM/GBSA. KLK14 was successfully modeled. Calculated free energies suggested higher binding affinity for the KLK14/HAI-1 interaction than for KLK14/HAI-2. This difference in binding affinity is largely explained by the higher stability of the hydrogen-bond networks in KLK14/HAI-1 along the simulation trajectory. A key arginine residue in both HAI-1 and HAI-2 is responsible for their interaction with the S1 pocket in KLK14. Additionally, MM/GBSA free-energy decomposition postulates that KLK14 Asp174 and Trp196 are hotspots for binding HAI-1 and HAI-2.

In vitro evidence that KLK14 regulates the components of the HGF/Met axis, pro-HGF and HGF-activator inhibitor 1A and 1B

Kallikrein-related peptidase (KLK) 14 is a serine protease linked to several pathologies including prostate cancer. We show that KLK14 has biphasic effects in vitro on activating and inhibiting components of the prostate cancer associated hepatocyte growth factor (HGF)/Met system. At 5–10 nm, KLK14 converts pro-HGF to the two-chain heterodimer required for Met activation, while higher concentrations degrade the HGF α-chain. HGF activator-inhibitor (HAI)-1A and HAI-1B, which inhibit pro-HGF activators, are degraded by KLK14 when protease:inhibitor stoichiometry is 1:1 or the protease is in excess. When inhibitors are in excess, KLK14 generates HAI-1A and HAI-1B fragments known to inhibit pro-HGF activating serine proteases. These in vitro data suggest that increased KLK14 activity could contribute at multiple levels to HGF/Met-mediated processes in prostate and other cancers.

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.

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.

Urinary aHGF, IGFBP3 and OPN as diagnostic and prognostic biomarkers for prostate cancer

AIM

Serum PSA screening for prostate cancer (PCa) is controversial. Here, we identify three urinary biomarkers - aHGF, IGFBP3 and OPN - for PCa screening and prognostication.

METHODS

Urinary aHGF, OPN and IGFBP3 from healthy men (n = 19) and men with localized (n = 65) and metastatic (n = 36) PCa were quantified via ELISA. Mann-Whitney nonparametric t-test and the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) analyses were used to analyze associations.

RESULTS

Mean aHGF and IGFBP3 levels were significantly elevated in PCa patients versus controls (p = 0.0006 and p = 0.0012, respectively), and the area under the curve of the receiver operating characteristic curve (indicator of diagnostic accuracy) for aHGF and IGFBP3 was 0.75 and 0.74, respectively. OPN levels were significantly higher in metastatic groups (p = 0.0060) versus localized and controls (area under the curve = 0.68).

CONCLUSION

Urinary aHGF and IGFBP3 exhibit the capacity for diagnostic discrimination for PCa, whereas OPN may indicate presence of metastatic disease.

Targeted proteomics pipeline reveals potential biomarkers for the diagnosis of metastatic lung cancer in pleural effusion

The ability to discriminate lung cancer malignant pleural effusion (LC-MPE) from benign pleural effusion has profound implications for the therapy and prognosis of lung cancer. Here, we established a pipeline to verify potential biomarkers for this purpose. In the discovery phase, label-free quantification was performed for the proteome profiling of exudative pleural effusion in order to select 34 candidate biomarkers with significantly elevated levels in LC-MPE. In the verification phase, signature peptides for 34 candidates were first confirmed by accurate inclusion mass screening (AIMS). To quantify the candidates in PEs, multiple reaction monitoring mass spectrometry (MRM-MS) with stable isotope-labeled standards (SIS) peptides was performed for the 34 candidate biomarkers using the QconCAT approach for the generation of the SIS peptides. The results of the MRM assay were used to prioritize candidates based on their discriminatory power in 82 exudative PE samples. The five potential biomarkers (ALCAM, CDH1, MUC1, SPINT1, and THBS4; AUC > 0.7) and one three-marker panel (SPINT1/SVEP1/THBS4; AUC = 0.95) were able to effectively differentiate LC-MPE from benign PE. Collectively, these results demonstrate that our pipeline is a feasible platform for verifying potential biomarkers for human diseases.

Hepatocyte growth factor activator inhibitor type 2 (HAI-2) modulates hepcidin expression by inhibiting the cell surface protease matriptase-2

Matriptase-2, a recently identified cell surface protease, is the key enzyme of iron homoeostasis modulating the expression of the liver peptide hormone hepcidin. HAI (hepatocyte growth factor activator inhibitor) types 1 and 2 (HAI-1 and HAI-2 respectively) have been shown to inhibit the close homologue, i.e. matriptase. By co-expressing matriptase-2 and the inhibitor HAI-2 we have identified HAI-2 displaying high inhibitory potential against matriptase-2 at the cell surface as well as in conditioned medium. Accordingly, complex formation between matriptase-2 and HAI-2 was demonstrated by isolation of the complex via immobilizing either HAI-2 or matriptase-2 from lysates and conditioned medium of co-expressing cells. Furthermore, HAI-2 indirectly influences the expression of the hepcidin-encoding gene HAMP. The inhibitor abrogates the matriptase-2-mediated suppression of HAMP expression, presumably by inhibiting the supposed potential of matriptase-2 to cleave membrane-bound HJV (haemojuvelin). Taken together, the results of the present study have characterized HAI-2 as an inhibitor of matriptase-2 that modulates the synthesis of hepcidin and provides new insights into the regulatory mechanism of iron homoeostasis, with clinical importance for a treatment of iron overload diseases.

Combined proteome and transcriptome analyses for the discovery of urinary biomarkers for urothelial carcinoma

Background:

Proteomic discovery of cancer biomarkers in body fluids is challenging because of their low abundance in a complex background. Altered gene expression in tumours may not reflect protein levels in body fluids. We have tested combining gene expression profiling of tumours with proteomic analysis of cancer cell line secretomes as a strategy to discover urinary biomarkers for bladder cancer.

Methods:

We used shotgun proteomics to identify proteins secreted by three bladder cancer cell lines. Secreted proteins with high mRNA levels in bladder tumours relative to normal urothelium were assayed by ELISA in urine samples from 642 patients.

Results:

Midkine and HAI-1 were significantly increased in bladder cancer patients, with the highest levels in invasive disease (area under the receiver operating characteristic curve 0.89 vs non-cancer). The urinary concentration of both proteins was too high to be explained by bladder cancer associated haematuria and most likely arises by direct tumour secretion.

Conclusions:

This ‘dual-omic' strategy identified tumour secreted proteins whose urine concentrations are increased significantly by bladder cancer. Combined secretome-transcriptome analysis may be more useful than direct proteomic analysis of body fluids for biomarker discovery in both bladder cancer and other tumour types.

Loss of the matriptase inhibitor HAI-2 during prostate cancer progression

BACKGROUND

Prostate cancer progression is accompanied by increased levels of extracellular proteases that are capable of remodeling the extracellular matrix as well as cleaving and activating growth factors and their receptors that are critically involved in pro-cancerous signaling pathways. The membrane anchored serine protease matriptase (also known as MT-SP1, epithin, and TADG15) has been implicated in prostate cancer. Several studies have demonstrated that the expression of this protease, both on the RNA and protein level is significantly increased during prostate cancer progression. Hepatocyte activator growth factor inhibitor-2 (HAI-2) has recently been identified as a physiological inhibitor of matriptase. It has been proposed that the increase of matriptase with a concomitant loss of its inhibitors may play a critical role in cancer progression.

METHODS

In this study, we used immunohistochemistry to determine the expression of HAI-2 protein in 136 prostate cancer samples, 20 prostate benign prostatic hyperplasia (BPH) samples, and 31 normal or tumor-adjacent prostate samples. Specificity of detection was ensured by using two unrelated HAI-2 antibodies and corresponding non-immune IgG antibodies.

RESULTS

We demonstrate that HAI-2 protein is significantly decreased in malignant lesions as compared to normal and BPH lesions, and that the most poorly differentiated tumors (Gleason score 8-10) have the lowest level of HAI-2 expression.

CONCLUSION

These data suggest that the loss of HAI-2 may be actively involved in prostate cancer progression by causing a reduced inhibitory capacity of proteolysis possibly of the physiological target for HAI-2 matriptase.

Serum active hepatocyte growth factor (AHGF) in benign prostatic disease and prostate cancer

BACKGROUND

Hepatocyte growth factor (HGF) is secreted as an inactive single-chain precursor called pro-HGF. Pro-HGF is converted to an active two-chain form by HGF activator and matriptase. We attempted to clarify whether serum levels of active HGF (AHGF) could be used as a marker of prostate cancer.

METHODS

Serum levels of AHGF and total HGF (THGF; pro-HGF + AHGF) were measured by enzyme-linked immunosorbent assay in 38 patients with benign prostatic disease and 160 patients with prostate cancer.

RESULTS

Serum levels of AHGF in patients with untreated prostate cancer (0.37 +/- 0.12 ng/ml) were significantly higher than those in patients with benign prostatic disease (0.28 +/- 0.08 ng/ml) (P = 0.0001). Serum AHGF levels were increased in patients with stage D or D3 compared with stage B. In addition, there were significant differences in serum AHGF levels between patients with well-differentiated and poorly differentiated adenocarcinoma. Furthermore, the mean serum AHGF/THGF ratio in patients with stage D3 prostate cancer was significantly higher than that in patients with stage B.

CONCLUSIONS

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

Exploration of target molecules for prostate cancer gene therapy

BACKGROUND

Focusing on Adv-FZ33, a modified adenovirus in which a synthetic 33-amino-acid immunoglobulin G-binding domain was inserted into the adenoviral fiber protein, we tried to identify suitable target molecules for prostate cancer-specific gene therapy.

METHODS

Hybridomas were established from mice immunized with prostate cancer cell lines. The hybridomas were screened using Adv-FZ33 to create monoclonal antibodies (mAbs) that induced high gene transfer efficiency for PC-3 cells. Furthermore, we identified target antigens of the mAbs by immunoprecipitation and mass spectrometry, and investigated the expression of target molecules by flow cytometry and immunocytochemistry.

RESULTS

Using Adv-FZ33, we established four different mouse mAbs that increased transduction efficiency for PC-3. The target antigens identified were Ep-CAM, CD155, HAI-1, and Na,K-ATPase beta1. These antigens were expressed in several cancer cell lines, including prostate cancer. Human prostatic myofibroblast cells lacked expression of Ep-CAM and HAI-1.

CONCLUSIONS

We established anti-Ep-CAM mAb and anti- HAI-1 mAbs. Gene transduction via Ep-CAM and HAI-1 may be a novel strategy for treatment of prostate cancer.