Kallikreins as Markers of Disseminated Tumour Cells in Ovarian Cancer – A Pilot Study

Diagnostic value of HE4+ circulating tumor cells in patients with suspicious ovarian cancer

Lacking a satisfactory screening test, ovarian cancer is frequently diagnosed at a late stage, leading to poor patient outcomes. This study investigated the diagnostic value of circulating tumor cells (CTCs) in peripheral blood from patients with suspected ovarian tumors. Sixty-one women suspected of having an ovarian mass were prospectively enrolled in this study. CTCs were identified and counted using microfluidic isolation and immunofluorescent staining of CD45, HE4, and epithelial and mesenchymal (E&M) markers (epithelial cell adhesion molecule, cytokeratins, and vimentin). Thirty (49%) of the patients were diagnosed with ovarian cancer. DAPI+/E&M+/CD45-/HE4+ CTC counts were higher in these patients than in patients with benign tumors (p = 0.016). The receiver operating characteristic (ROC) curve showed that the sensitivity of CTCs was 73.3%, which was superior to that of CA125 (56.7%). In patients with elevated CA125 levels (≥35 U/ml), CTC counts still showed good specificity (86.7%). Our findings suggest the DAPI+/E&M+/CD45-/HE4+ CTC count is a useful diagnostic indicator in patients with suspected ovarian cancer.

Circulating cell-free DNA and circulating tumor cells, the "liquid biopsies" in ovarian cancer

Limited understanding of ovarian cancer (OC) genome portrait has hindered the therapeutic advances. The serial monitoring of tumor genotypes is becoming increasingly attainable with circulating cell-free DNA (cf-DNA) and circulating tumor cells (CTCs) emerging as “liquid biopsies”. They represent non-invasive biomarkers and are viable, as they can be isolated from human plasma, serum and other body fluids. Molecular characterization of circulating tumor DNA (ct-DNA) and CTCs offer unique potentials to better understand the biology of metastasis and resistance to therapies. The liquid biopsies may also give innovative insights into the process of rapid and accurate identification, resistant genetic alterations and a real time monitoring of treatment responses. In addition, liquid biopsies are shedding light on elucidating signal pathways involved in invasiveness and metastasis competence; but the detection and molecular characterization of ct-DNA and CTCs are still challenging, since they are rare, and the amount of available samples are very limited. This review will focus on the clinical potential of ct-DNA and CTCs in both the early and advanced diagnosis, prognosis, and in the identification of resistance mutations in OC.

Methodology and Applications of Disease Biomarker Identification in Human Serum

Biomarkers are biomolecules that serve as indicators of biological and pathological processes, or physiological and pharmacological responses to a drug treatment. Because of the high abundance of albumin and heterogeneity of plasma lipoproteins and glycoproteins, biomarkers are difficult to identify in human serum. Due to the clinical significance the identification of disease biomarkers in serum holds great promise for personalized medicine, especially for disease diagnosis and prognosis. This review summarizes some common and emerging proteomics techniques utilized in the separation of serum samples and identification of disease signatures. The practical application of each protein separation or identification technique is analyzed using specific examples. Biomarkers of cancers of prostate, breast, ovary, and lung in human serum have been reviewed, as well as those of heart disease, arthritis, asthma, and cystic fibrosis. Despite the advancement of technology few biomarkers have been approved by the Food and Drug Administration for disease diagnosis and prognosis due to the complexity of structure and function of protein biomarkers and lack of high sensitivity, specificity, and reproducibility for those putative biomarkers. The combination of different types of technologies and statistical analysis may provide more effective methods to identify and validate new disease biomarkers in blood.

Kallikrein 4 and matrix metalloproteinase-20 immunoexpression in malignant, benign and infiltrative odontogenic tumors

CONTEXT

Matrix metalloproteinase-20 (MMP20) (enamelysin) and kallikrein 4 (KLK4) are enzymes secreted by ameloblasts that play an important role in enamel matrix degradation during amelogenesis. However, studies have shown that neoplastic cells can produce such enzymes, which may affect the tumor infiltrative and metastatic behaviors.

AIMS

The aim of this study is to assess the biological role of MMP20 and KLK4 in odontogenic tumors.

MATERIALS AND METHODS

The enzymes were analyzed immunohistochemically in ameloblastoma, adenomatoid odontogenic tumor (AOT), calcifying epithelial odontogenic tumor, keratocystic odontogenic tumor with or without recurrence and odontogenic carcinoma.

STATISTICAL ANALYSIS USED

Clinicopathological parameters were statistically correlated with protein expression using the Fisher's exact test. Kruskal-Wallis and Wilcoxon-independent methods were used to evaluate the differences in median values.

RESULTS

Positive Immunoexpression was detected in all benign lesions, with a prevalence of 75-100% immunolabeled cells. Patients were predominantly young, Caucasian, female, with slow-growing tumors located in the mandible causing asymptomatic swelling. No KLK4 expression was seen in carcinomas, and the amount of MMP20-positive cells varied between 20% and 80%. Rapid evolution, recurrence and age >60 years characterized the malignant nature of these lesions.

CONCLUSIONS

Data showed that KLK4 and MMP20 enzymes may not be crucial to tumoral infiltrative capacity, especially in malignant tumors, considering the diversity and peculiarity of these lesions. The significant immunoexpression in benign lesions, remarkably in AOT, is likely associated with differentiated tumor cells that can produce and degrade enamel matrix-like substances. This would be expected since the histogenesis of odontogenic tumors commonly comes from epithelium that recently performed a secretory activity in tooth formation.

The serine protease prostasin (PRSS8) is a potential biomarker for early detection of ovarian cancer

Background

Ovarian cancer (OVC) is the deadliest of all gynecologic cancers, primarily as a consequence of asymptomatic progression. The complex nature of OVC creates challenges for early detection, and there is a lack of specific and sensitive biomarkers suitable for screening and detecting early stage OVC.

Methods

Potential OVC biomarkers were identified by bioinformatic analysis. Candidates were further screened for differential expression in a library of OVC cell lines. OVC-specific overexpression of a candidate gene, PRSS8, which encodes prostasin, was confirmed against 18 major human cancer types from 390 cancer samples by qRT-PCR. PRSS8 expression profiles stratified by OVC tumor stage-, grade- and subtype were generated using cDNA samples from 159 OVC samples. Cell-specific expression and localization of prostasin was determined by immunohistological tissue array analysis of more than 500 normal, benign, and cancerous ovarian tissues. The presence of prostasin in normal, benign, and OVC serum samples was also determined.

Results

Gene expression analysis indicated that PRSS8 was expressed in OVC at levels more than 100 fold greater than found in normal or benign ovarian lesions. This overexpression signature was found in early stages of OVC and was maintained in higher stages and grades of OVC. The PRSS8 overexpression signature was specific for OVC and urinary bladder cancer among 18 human cancer types. The majority of ovarian cell lines overexpressed PRSS8. In situ hybridization and histopathology studies of OVC tissues indicated that overexpression of prostasin was largely localized to tumor epithelium and was absent in neighboring stroma. Significantly higher levels of prostasin were found in early stage OVC serum samples compared to benign ovarian and normal donor samples.

Conclusions

The abundant amounts of secreted prostasin found in sera of early stage OVC can potentially be used as a minimally invasive screening biomarker for early stage OVC. Overexpression of PRSS8 mRNA and high levels of prostasin in multiple subtypes of early stage ovarian tumors may provide clinical biomarkers for early detection of OVC, which can potentially be used with CA125 and HE4.

Electronic supplementary material

The online version of this article (doi:10.1186/s13048-016-0228-9) contains supplementary material, which is available to authorized users.

Involvement of Kallikrein-Related Peptidases in Normal and Pathologic Processes

Human kallikrein-related peptidases (KLKs) are a subgroup of serine proteases that participate in proteolytic pathways and control protein levels in normal physiology as well as in several pathological conditions. Their complex network of stimulatory and inhibitory interactions may induce inflammatory and immune responses and contribute to the neoplastic phenotype through the regulation of several cellular processes, such as proliferation, survival, migration, and invasion. This family of proteases, which includes one of the most useful cancer biomarkers, kallikrein-related peptidase 3 or PSA, also has a protective effect against cancer promoting apoptosis or counteracting angiogenesis and cell proliferation. Therefore, they represent attractive therapeutic targets and may have important applications in clinical oncology. Despite being intensively studied, many gaps in our knowledge on several molecular aspects of KLK functions still exist. This review aims to summarize recent data on their involvement in different processes related to health and disease, in particular those directly or indirectly linked to the neoplastic process.

Optimizing molecular-targeted therapies in ovarian cancer: the renewed surge of interest in ovarian cancer biomarkers and cell signaling pathways

The hallmarks of ovarian cancer encompass the development of resistance, disease recurrence and poor prognosis. Ovarian cancer cells express gene signatures which pose significant challenges for cancer drug development, therapeutics, prevention and management. Despite enhancements in contemporary tumor debulking surgery, tentative combination regimens and abdominal radiation which can achieve beneficial response rates, the majority of ovarian cancer patients not only experience adverse effects, but also eventually relapse. Therefore, additional therapeutic possibilities need to be explored to minimize adverse events and prolong progression-free and overall response rates in ovarian cancer patients. Currently, a revival in cancer drug discovery is devoted to identifying diagnostic and prognostic ovarian cancer biomarkers. However, the sensitivity and reliability of such biomarkers may be complicated by mutations in the BRCA1 or BRCA2 genes, diverse genetic risk factors, unidentified initiation and progression elements, molecular tumor heterogeneity and disease staging. There is thus a dire need to expand existing ovarian cancer therapies with broad-spectrum and individualized molecular targeted approaches. The aim of this review is to profile recent developments in our understanding of the interrelationships among selected ovarian tumor biomarkers, heterogeneous expression signatures and related molecular signal transduction pathways, and their translation into more efficacious targeted treatment rationales.

The physiology and pathobiology of human kallikrein-related peptidase 6 (KLK6)

The human kallikrein-related peptidase 6 (KLK6) gene belongs to the 15-member kallikrein (KLK) gene family mapping to chromosome 19q13.3-13.4. Encoding for an enzyme with trypsin-like properties, KLK6 can degrade components of the extracellular matrix. The successful utilisation of another KLK member (KLK3/PSA) for prostate cancer diagnosis has led many to evaluate KLK6 as a potential biomarker for other cancer and diseased states. The observed dysregulated expression in cancers, neurodegenerative diseases and skin conditions has led to the discovery that KLK6 participates in other cellular pathways including inflammation, receptor activation and regulation of apoptosis. Moreover, the improvements in high-throughput genomics have not only enabled the identification of sequence polymorphisms, but of transcript variants, whose functional significances have yet to be realised. This comprehensive review will summarise the current findings of KLK6 pathophysiology and discuss its potential as a viable biomarker.

Functional proteomics of kallikrein-related peptidases in ovarian cancer ascites fluid

Kallikrein-related peptidases (KLKs) are secreted serine proteinases with trypsin or chymotrypsin-like activity. Several family members, such as KLKs 6 and 10, are potential ovarian cancer biomarkers. Recently, using a newly developed assay for active KLK6, we found that only a very small proportion of immunoreactive KLK6 in tumor-derived clinical samples (malignant ascites fluid), in cerebrospinal fluid, and in cancer cell line supernatants is enzymatically active. We therefore hypothesized that a proportion of other immunoreactive KLKs in such samples could be present, but might be partly complexed to endogenous serine proteinase inhibitors. Using a combination of immunological isolation of the enzymes, activity-based probe analysis and proteomics, we identified active KLK10 in ovarian cancer ascites and we provide preliminary data that the activity of other KLKs present in these samples can be decreased by known proteinase inhibitors (e.g., alpha2-macroglobulin, alpha1-antitrypsin). Our data suggest that the enzymatic activity of ovarian cancer-released KLKs that are detected by regular immunoassays is low in vivo and very likely regulated by proteinase inhibitors.

Expression analysis and study of the KLK15 mRNA splice variants in prostate cancer and benign prostatic hyperplasia

Prostate cancer is the most commonly diagnosed malignancy in male populations in the Western world. The KLK15 gene, the newest member of the kallikrein family, is expressed in the prostate gland. The purpose of this study is the expression analysis and the clinical evaluation of the KLK15 mRNA spliced variants in prostate cancer (CaP) and benign prostatic hyperplasia (BPH) patients. Total RNA was isolated from 104 CaP and BPH tissue specimens. After testing the quality of the RNA, cDNA was produced by reverse transcription, and PCR was performed for the amplification of the KLK15 mRNA transcripts. GAPDH and HPRT genes were used as endogenous controls Our data revealed that mRNA spliced variants of KLK15 were differentially expressed in prostate tissue specimens. Analysis of data showed a statistically significant (P < 0.001) increase in the frequency of overexpression of KLK15 transcripts encoding for both the active isoform and for the isoform 3 in CaP compared to BPH samples. Furthermore, KLK15 transcripts were found to be highly expressed in more aggressive tumors (P = 0.017). These results suggest that KLK15 expression analysis could be employed as a valuable tool for the discrimination between BPH and CaP tissue specimens and as an unfavorable prognostic marker for prostate cancer.

Phase II trial of single agent cetuximab in patients with persistent or recurrent epithelial ovarian or primary peritoneal carcinoma with the potential for dose escalation to rash

OBJECTIVES

Determine if cetuximab dose escalation to induce grade 2 rash correlates with anti-tumor activity and if sera-based markers could predict likelihood of response.

METHODS

Patients with persistent/recurrent ovarian or primary peritoneal carcinoma received an initial dose of cetuximab 400 mg/m(2), then 250 mg/m(2) weekly for two 3-week cycles. Patients who had stable disease (SD) and <grade 2 rash were dose escalated in 75 mg/m(2) increments every 3 weeks until grade 2 rash or to a maximum weekly dose of 400 mg/m(2). Pre- and post-treatment serum samples were evaluated for potential predictive markers of response.

RESULTS

One of 25 patients achieved partial remission (PR) and 9 patients had SD. The median progression free survival was 2.1 months; the 1-year survival rate was 54.8%. Rash (96%) was the most common drug-related adverse event. At first response assessment, 4 patients remained at 250 mg/m(2); 8 patients were dose-escalated to 325 mg/m(2); of these, 4 ultimately were increased to 400 mg/m(2). Patients with progressive disease (PD) were removed from the study. Ninety-two serologic markers were analyzed from 20 patients to identify markers associated with clinical activity and/or predictive of outcome. Pretreatment levels of twelve markers were significantly elevated in patients exhibiting PD versus SD or PR; however, changes in marker levels during the course of treatment were not significant indicators of response.

CONCLUSIONS

Single-agent cetuximab showed minimal activity in patients with recurrent ovarian cancer. Patients with elevated levels of 12 serologic markers at baseline were more likely to have earlier disease progression.

Prediction of ovarian cancer prognosis and response to chemotherapy by a serum-based multiparametric biomarker panel

Currently, there are no effective biomarkers for ovarian cancer prognosis or prediction of therapeutic response. The objective of this study was to examine a panel of 10 serum biochemical parameters for their ability to predict response to chemotherapy, progression and survival of ovarian cancer patients. Sera from ovarian cancer patients were collected prior and during chemotherapy and were analysed by enzyme-linked immunosorbent assay for CA125, kallikreins 5, 6, 7, 8, 10 and 11, B7-H4, regenerating protein IV and Spondin-2. The odds ratio and hazard ratio and their 95% confidence interval (95% CI) were calculated. Time-dependent receiver-operating characteristic (ROC) curves were utilised to evaluate the prognostic performance of the biomarkers. The levels of several markers at baseline (c₀), or after the first chemotherapy cycle (rc₁), predicted chemotherapy response and overall or progression-free survival in univariate analysis. A multiparametric model (c₀ of CA125, KLK5, KLK7 and rc₁ of CA125) provided predictive accuracy with area under the ROC curve (AUC) of 0.82 (0.62 after correction for overfitting). Another marker combination (c₀ of KLK7, KLK10, B7-H4, Spondin-2) was useful in predicting short-term (1-year) survival with an AUC of 0.89 (0.74 after correction for overfitting). All markers examined, except KLK7 and regenerating protein IV, were powerful predictors of time to progression (TTP) among chemotherapy responders. Individual and panels of biomarkers from the kallikrein family (and other families) can predict response to chemotherapy, overall survival, short-term (1-year) survival, progression-free survival and TTP of ovarian cancer patients treated with chemotherapy.

Distribution of 15 Human Kallikreins in Tissues and Biological Fluids

Background: Kallikreins (KLKs) are a group of 15 secreted serine proteases. Some KLKs are established or candidate cancer biomarkers, but for most the physiological function is unknown. We characterized the protein and mRNA abundance patterns of all 15 KLKs in multiple panels of human tissues and biological fluids.

Methods: We used sensitive and specific sandwich-type ELISAs for each KLK. Reverse transcription PCR was used for transcript amplification. Multiple panels of human tissue extracts (adult and fetal) were tested, along with various biological fluids.

Results: Quantitative protein expression data on 7 sets of adult and 3 sets of fetal tissues were collected for all 15 KLKs. KLKs were also quantified in the following biological fluids: seminal plasma, breast milk, follicular fluid, breast cyst fluid, breast cancer cytosol, amniotic fluid, ovarian cancer ascites, cerebrospinal fluid, cervicovaginal fluid, and urine. The data were used to generate heat maps of KLK concentrations in tissues and fluids and categorize KLK abundance as highly restricted (KLK2 and KLK3 in prostate), restricted (KLK5 in skin, salivary gland, breast, and esophagus; KLK6 in brain and central nervous system; KLK7 in esophagus, heart, liver, and skin; KLK8 in breast, esophagus, skin, and tonsil; KLK13 in esophagus and tonsil), or wide (KLKs 1, 4, 9, 10, 11, 12, 14, and 15).

Conclusions: Quantitative KLK concentrations in tissues and fluids aid in the elucidation of KLK function, and coexpression patterns provide clues for KLK participation in proteolytic cascades.

Ovarian cancer specific kallikrein profile in effusions

OBJECTIVE

Kallikreins belong to the serine protease family and their roles as cancer associated markers have been proposed. However, a comprehensive and parallel analysis of different secreted kallikreins in ovarian cancer has not been performed. This study was undertaken to profile the secreted kallikreins in cancer effusion supernatants.

METHODS

We applied ELISA to measure the protein levels of nine kallikreins (4-8, 10, 11, 13, and 14) in a total of 221 effusion supernatants obtained from ovarian cancer, benign non-neoplastic diseases and a variety of other neoplastic diseases.

RESULTS

Our results demonstrated that ovarian cancer effusions contained higher levels of all kallikreins analyzed except kallikrein 4, as compared to benign effusions (p<0.0005) and other cancer types (p<0.03). Unsupervised principal component analyses demonstrated a unique cluster of ovarian cancer samples which were distinct from benign effusions and other cancer groups based on measurements of secreted kallikreins 5-8, 10, 11, 13 and 14. Supervised combinations of the eight kallikreins achieved areas under ROC curve of 0.994 and 0.961 in separating ovarian cancer from benign effusion groups and other cancer groups, respectively. Among kallikreins, kallikreins 6, 7, 8, and 10 showed the highest statistical power in distinguishing ovarian cancer from benign controls and other cancer groups and these kallikreins could diagnose false negative cases based on cytology.

CONCLUSIONS

The above findings indicate that kallikreins 6, 7, 8 and 10 are the four most specific secreted kallikreins in ovarian cancer. These kallikreins may have clinical implications in the differential diagnosis of ovarian carcinoma from benign diseases and other cancer types.

Placental mesenchymal dysplasia associated with hepatic mesenchymal hamartoma in the newborn

Placental mesenchymal dysplasia is an uncommon disorder in which the placenta is enlarged with abnormal, large, and often cystic villi with dilated and/or thick-walled vessels. These placental changes can mimic a partial hydatidiform mole but in contrast to a partial mole can coexist with a fully viable fetus. Fetal anatomical and vascular anomalies frequently coexist with placental mesenchymal dysplasia. In this case, placental mesenchymal dysplasia was associated with preterm labor at 33 weeks' gestation, fetal compromise, and a large abdominal mass with a large hepatic cyst that was de-roofed at exploratory laparotomy. The neonate remained critically ill with hypoxic ischaemic encephalopathy and coagulopathy and died despite intensive care. Biopsy and autopsy findings showed a large cystic mesenchymal hamartoma affecting the left lobe of the liver. This appears to be the 3rd histologically confirmed association of placental mesenchymal dysplasia with mesenchymal hamartoma of the liver in the English language literature.

Coordinated steroid hormone-dependent and independent expression of multiple kallikreins in breast cancer cell lines

The regulation of gene expression by steroid hormones plays an important role in the normal development and function of many organs, as well in the pathogenesis of endocrine-related cancers. Previous experiments have shown that many kallikrein genes are under steroid hormone regulation in breast cancer cell lines. We here examine the coordinated expression of multiple kallikrein genes in several breast cancer cell lines after steroid hormone stimulation. Breast cancer cell lines were treated with various steroid hormones and kallikrein (KLK/hK) expression of hK3 (prostate-specific antigen, PSA), hK5, hK6, hK7, hK8, hK10, hK11, hK13, and hK14 was analyzed at the RNA level via RT-PCR and at the protein level by immunofluorometric ELISA assays. We identified several distinct hK hormone-dependent and hormone-independent expression patterns. Hormone-specific modulation of expression was seen for several kallikreins in BT-474, MCF-7, and T-47D cell lines. hK6 was specifically up-regulated upon estradiol treatment in all three cell lines whereas PSA expression was induced by dihydrotestosterone (DHT) and norgestrel stimulation in BT-474 and T-47D. hK10, hK11, hK13, and hK14 were specifically up-regulated by DHT in T-47D and by estradiol in BT-474 cells. Bioinformatic analysis of upstream proximal promoter sequences for these hKs did not identify any recognizable hormone-response elements (HREs), suggesting that the coordinated activation of these four hKs represents a unique expression "cassette", utilizing a common hormone-dependent mechanism. We conclude that groups of human hKs are coordinately expressed in a steroid hormone-dependent manner. Our data supports clinical observations linking expression of multiple hKs with breast cancer prognosis.