Human kallikrein 8 expression in salivary gland tumors

KLK8 promotes the proliferation and metastasis of colorectal cancer via the activation of EMT associated with PAR1

Kallikrein-related peptidase 8 (KLK8) acts as an oncogene or anti-oncogene in various tumours, and the abnormal expression of KLK8 is involved in the carcinogenesis of several tumours. However, the role of KLK8 in colorectal cancer (CRC) and the underlying mechanism remain largely unclear. In this study, the carcinogenic effect of KLK8 was determined via CCK-8 and colony formation assays in vitro and a xenograft model in nude mice in vivo. The metastasis-promoting effect of KLK8 was investigated with transwell migration and invasion assays and wound-healing assay in vitro and a metastasis model in nude mice in vivo. Bioinformatics analyses and mechanistic experiments were conducted to elucidate the molecular mechanism. Herein, we reported that KLK8 had a promotive effect on the proliferation, migration and invasion of RKO and SW480 cells. Epithelial-mesenchymal transition (EMT) played an important role in the promotive effects of KLK8 on CRC. In addition, protease-activated receptor-1 (PAR-1) antagonist SCH79797 but not protease-activated receptor-2 (PAR-2) antagonist FSLLRY-NH2 attenuated the proliferation, migration and invasion of KLK8-upregulated RKO and SW480 cells. PAR-1 antagonist SCH79797 reduced the tumour volume of xenograft model and decreased the metastatic nodules in the livers of metastasis model. Furthermore, SCH79797 could reverse the positive impact of KLK8 on the EMT process in CRC both in vitro and in vivo. Taken together, these findings demonstrated for the first time that KLK8 promoted EMT and CRC progression, and this effect might be, at least partly mediated by PAR1-dependent pathway.

Upregulation of KLK8 Predicts Poor Prognosis in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is a growing cause of cancer-related mortality worldwide. Kallikrein-related peptidase 8 (KLK8) has potential clinical values in many cancers. However, the clinicopathological significances of KLK8 in PDAC remain unknown. We explored the relationship of KLK8 to clinicopathological features of PDAC based on public databases. KLK8 expression was examined in human PDAC tissues. Cell proliferation and apoptosis were evaluated in KLK8-overexpressed human pancreatic cancer cell lines Mia-paca-2 and Panc-1. The related signaling pathways of KLK8 involved in pancreatic cancer progression were analyzed by gene set enrichment analysis (GSEA) and further verified in in vitro studies. We found that KLK8 was up-regulated in tumor tissues in the TCGA-PAAD cohort, and was an independent prognostic factor for both overall survival and disease-free survival of PDAC. KLK8 mRNA and protein expressions were increased in PDAC tissues compared with para-cancerous pancreas. KLK8 overexpression exerted pro-proliferation and anti-apoptotic functions in Mia-paca-2 and Panc-1 cells. GSEA analysis showed that KLK8 was positively associated with PI3K-Akt-mTOR and Notch pathways. KLK8-induced pro-proliferation and anti-apoptotic effects in Mia-paca-2 and Panc-1 cells were attenuated by inhibitors for PI3K, Akt, and mTOR, but not by inhibitor for Notch. Furthermore, overexpression of KLK8 in Mia-paca-2 and Panc-1 cells significantly increased epidermal growth factor (EGF) levels in the culture media. EGF receptor (EGFR) inhibitor could block KLK8-induced activation of PI3K/Akt/mTOR pathway and attenuate pro-proliferation and anti-apoptotic of KLK8 in Mia-paca-2 and Panc-1 cells. In conclusion, KLK8 overexpression exerts pro-proliferation and anti-apoptotic functions in pancreatic cancer cells via EGF signaling-dependent activation of PI3K/Akt/mTOR pathway. Upregulated KLK8 in PDAC predicts poor prognosis and may be a potential therapeutic target for PDAC.

Human Tissue Kallikreins in Polymorphous Adenocarcinoma: A Polymerase Chain Reaction and Immunohistochemical Study

Polymorphous adenocarcinoma (PAC) is the second most common malignant salivary gland tumour of minor salivary glands. Human tissue kallikreins (KLKs) are a family of highly conserved serine proteases expressed by various tissues and organs. The literature demonstrates a link between KLKs and salivary gland neoplasms. The purpose of this study was to determine levels of KLK mRNA in tissue samples of PAC and to determine if KLK expression is limited to tumour cells. Nineteen cases of PAC were reviewed (1987-2013). The diagnosis was confirmed, demographic data was collected, and formalin fixed paraffin-embedded PAC and normal salivary gland tissue samples were obtained. RNA isolation was achieved, followed by conversion to complementary DNA via reverse transcription. Using PCR, the quantitative level of expression of KLKs1-15 was recorded. Samples exhibiting high and low KLK expression were selected for immunohistochemistry staining. Results revealed a statistically significant increase in mean KLK mRNA expression for KLK1, KLK4, KLK10, KLK12 and KLK15 in PAC tissue samples, compared with normal salivary gland tissue (Mann-Whitney U test, p < 0.05). Immunohistochemistry results demonstrated that KLKs were present in tumor cells. Notably, all samples demonstrating relatively higher KLK mRNA expression showed equivalent or increased staining scores relative to the low KLK mRNA expression samples. In conclusion, there appears to be aberrant kallikrein expression in polymorphous adenocarcinoma, suggesting the possibility of a kallikrein cascade influence on tumor development and progression.

Saliva proteomic patterns in patients with molar incisor hypomineralization

Molar incisor hypomineralization (MIH) is an endemic pediatric disease with an unclear pathogenesis. Considering that saliva controls enamel remineralization and that MIH is associated with higher saliva flow rate, we hypothesized that the protein composition of saliva is linked to disease. To test this, we enrolled 5 children aged 6-14 years with MIH showing at least one hypersensitive molar and 5 caries-free children without hypomineralization. Saliva samples were subjected to proteomic analysis followed by protein classification in to biological pathways. Among 618 salivary proteins identified with high confidence, 88 proteins were identified exclusively in MIH patients and 16 proteins in healthy controls only. Biological pathway analysis classified these 88 patient-only proteins to neutrophil-mediated adaptive immunity, the activation of the classical pathway of complement activation, extracellular matrix degradation, heme scavenging as well as glutathione -and drug metabolism. The 16 controls-only proteins were associated with adaptive immunity related to platelet degranulation and the lysosome. This report suggests that the proteaneous composition of saliva is affected in MIH patients, reflecting a catabolic environment which is linked to inflammation.

Differential roles of protease isoforms in the tumor microenvironment

Alternative splicing of precursor mRNA is a key mediator of gene expression regulation leading to greater diversity of the proteome in complex organisms. Systematic sequencing of the human genome and transcriptome has led to our understanding of how alternative splicing of critical genes leads to multiple pathological conditions such as cancer. For many years, proteases were known only for their roles as proteolytic enzymes, acting to regulate/process proteins associated with diverse cellular functions. However, the differential expression and altered function of various protease isoforms, such as (i) anti-apoptotic activities, (ii) mediating intercellular adhesion, and (iii) modifying the extracellular matrix, are evidence of their specific contribution towards shaping the tumor microenvironment. Revealing the alternative splicing of protease genes and characterization of their protein products/isoforms with distinct and opposing functions creates a platform to understand how protease isoforms contribute to specific cancer hallmarks. Here, in this review, we address cancer-specific isoforms produced by the alternative splicing of proteases and their distinctive roles in the tumor microenvironment.

Kallikrein-Related Peptidase mRNA Expression in Adenoid Cystic Carcinoma of Salivary Glands: A Polymerase Chain Reaction Study

Kallikrein-related peptidases (KLKs) are a group of 15 serine proteases implicated in a variety of biological processes. Aberrant expression of KLKs has been associated with the development of certain cancers. However, the role of KLKs in salivary tumors has not been extensively studied. This study evaluated the expression of KLKs in both adenoid cystic carcinoma (ACC) and normal salivary gland tissue. We isolated total RNA from 39 formalin-fixed, paraffin-embedded samples, which included 24 ACCs and 15 normal salivary gland tissues. Complementary DNA, synthesized by reverse transcription, was combined with gene specific kallikrein primers (KLK1-KLK15) to allow for quantitative real-time PCR. Data was normalized to a β-actin housekeeping gene. Relative quantification analysis was performed using the ΔCq method. KLK1-KLK15 expression was observed in both tissue types. However, KLK1, KLK8, KLK11, and KLK14 were found to be downregulated in ACC. We propose that this may represent a multi-parametric panel providing diagnostic and prognostic information.

Effect of Productive Human Papillomavirus 16 Infection on Global Gene Expression in Cervical Epithelium

Human papillomavirus (HPV) infection is the world's most common sexually transmitted infection and is responsible for most cases of cervical cancer. Previous studies of global gene expression changes induced by HPV infection have focused on the cancerous stages of infection, and therefore, not much is known about global gene expression changes at early preneoplastic stages of infection. We show for the first time the global gene expression changes during early-stage HPV16 infection in cervical tissue using 3-dimensional organotypic raft cultures, which produce high levels of progeny virions. cDNA microarray analysis showed that a total of 594 genes were upregulated and 651 genes were downregulated at least 1.5-fold with HPV16 infection. Gene ontology analysis showed that biological processes including cell cycle progression and DNA metabolism were upregulated, while skin development, immune response, and cell death were downregulated with HPV16 infection in cervical keratinocytes. Individual genes were selected for validation at the transcriptional and translational levels, including UBC, which was central to the protein association network of immune response genes, and top downregulated genes RPTN, SERPINB4, KRT23, and KLK8 In particular, KLK8 and SERPINB4 were shown to be upregulated in cancer, which contrasts with the gene regulation during the productive replication stage. Organotypic raft cultures, which allow full progression of the HPV life cycle, allowed us to identify novel gene modulations and potential therapeutic targets of early-stage HPV infection in cervical tissue. Additionally, our results suggest that early-stage productive infection and cancerous stages of infection are distinct disease states expressing different host transcriptomes.IMPORTANCE Persistent HPV infection is responsible for most cases of cervical cancer. The transition from precancerous to cancerous stages of HPV infection is marked by a significant reduction in virus production. Most global gene expression studies of HPV infection have focused on the cancerous stages. Therefore, little is known about global gene expression changes at precancerous stages. For the first time, we measured global gene expression changes at the precancerous stages of HPV16 infection in human cervical tissue producing high levels of virus. We identified a group of genes that are typically overexpressed in cancerous stages to be significantly downregulated at the precancerous stage. Moreover, we identified significantly modulated genes that have not yet been studied in the context of HPV infection. Studying the role of these genes in HPV infection will help us understand what drives the transition from precancerous to cancerous stages and may lead to the development of new therapeutic targets.

Increase of Serum Kallikrein-8 Level After Long-term Telbivudine Treatment

BACKGROUND/AIM

Our previous cDNA microarray study revealed increased cellular mRNA levels of a panel of genes, including kallikrein-8 (KLK8), after long-term telbivudine treatment in chronic hepatitis B patients. The aim of this study was to verify whether serum protein levels of KLK8, a cancer-related enzyme, are indeed increased after telbivudine treatment.

PATIENTS AND METHODS

A total of 83 chronic hepatitis B patients receiving telbivudine for >2 years were retrospectively analyzed. Serum KLK8 protein and estimated glomerular filtration rate (eGFR) changes were compared before and after treatment.

RESULTS

Both serum KLK8 protein and eGFR increased significantly after long-term telbivudine treatment (paired t-test: KLK8, p<0.001; eGFR, p=0.001). No direct correlation was found between KLK8 increase and eGFR change. However, eGFR change was positively associated with post-treatment KLK8 levels following adjustment for body height (p<0.001).

CONCLUSION

Telbivudine treatment resulted in increased levels of serum KLK8 protein. Furthermore, eGFR increase was associated with body height-adjusted, post-treatment KLK8 levels.

Identifying Candidate Biomarkers for Pleomorphic Adenoma: A Case-Control Study

Pleomorphic adenoma (PA) is the most common benign salivary gland tumor. Kallikrein-related peptidases have been identified as biomarkers in many human tumors and may influence tumor behavior. We investigated KLK1-15 messenger ribonucleic acid and proteins in PA specimens to determine a KLK expression profile for this tumor. Fresh frozen PA tissue specimens (n = 26) and matched controls were subjected to quantitative real-time reverse transcription polymerase chain reaction to detect KLK1-15 mRNA. Expression of KLK1, KLK12, KLK13, and KLK8 proteins were then evaluated via immunostaining techniques. Statistical analyses were performed with the level of significance set at P < .05. We observed downregulation of KLK1, KLK12, and KLK13 mRNA expression, and immunostaining studies revealed downregulation of the corresponding proteins. Histologic evidence of capsular perforation was associated with increased KLK1 protein expression. Tumor size was not associated with capsular invasion and/or perforation. This study is the first to detail a KLK expression profile for PA at both the transcriptional level and the protein level. Future work is required to develop clinical applications of these findings.

Increase of Serum Kallikrein-8 Level After Long-term Telbivudine Treatment

BACKGROUND/AIM

Our previous cDNA microarray study revealed increased cellular mRNA levels of a panel of genes, including kallikrein-8 (KLK8), after long-term telbivudine treatment in chronic hepatitis B patients. The aim of this study was to verify whether serum protein levels of KLK8, a cancer-related enzyme, are indeed increased after telbivudine treatment.

PATIENTS AND METHODS

A total of 83 chronic hepatitis B patients receiving telbivudine for >2 years were retrospectively analyzed. Serum KLK8 protein and estimated glomerular filtration rate (eGFR) changes were compared before and after treatment.

RESULTS

Both serum KLK8 protein and eGFR increased significantly after long-term telbivudine treatment (paired t-test: KLK8, p<0.001; eGFR, p=0.001). No direct correlation was found between KLK8 increase and eGFR change. However, eGFR change was positively associated with post-treatment KLK8 levels following adjustment for body height (p<0.001).

CONCLUSION

Telbivudine treatment resulted in increased levels of serum KLK8 protein. Furthermore, eGFR increase was associated with body height-adjusted, post-treatment KLK8 levels.

Human Kallikrein 14 (Klk14) Expression in Salivary Gland Tumors

Objective

To analyze the expression of human kallikrein 14 (KLK14) in salivary gland tumors.

Methods

A standard immunoperoxidase staining technique was used to assess the expression profile of KLK14 in normal salivary glands and tumors including pleomorphic adenoma (PA; n=17), adenoid cystic carcinoma (ACC; n=13) and mucoepidermoid carcinoma (MEC; n=9). Tumor stage, grade, patient age and gender, and site of occurrence were recorded. These clinical parameters were correlated with KLK14 levels in malignant tumors. The expression profiles for KLK3, 5, 6, 8 and 13 were also retrieved.

Results

Normal salivary glands, PA, ACC and MEC showed strong expression of KLK14 in ductal and non-ductal cells. Both PA and ACC showed higher KLK14 levels than normal glands and MEC tissues. There were no statistically significant associations between levels of KLK14 and clinical parameters.

Conclusions

The differences in the levels of KLK14 suggest that KLKs may aid in the differential diagnosis of salivary gland tumors. The coexpression of KLKs suggests their possible involvement in an enzymatic pathway activated in salivary gland. KLK14 may be a promising new biomarker in salivary gland tumors.

Elevated expression of KLK8 predicts poor prognosis in colorectal cancer

KLK8, also known as neuropsin, is one of fifteen members of the human kallikrein-related peptidase (KLK) gene family, which consists of enzymes with serine protease enzymatic activity. Aberrant KLK8 expression has been reported in several malignancies. However, the clinicopathological significance and prognostic value of KLK8 expression in colorectal cancer (CRC) are unknown. Therefore, analysis of public datasets, quantitative real-time PCR and western blot analysis were performed to assess KLK8 expression in CRC at both the mRNA and protein level. KLK8 expression was also assessed by immunohistochemistry in a tissue microarray containing 124 CRC specimens. We observed that KLK8 was overexpressed in CRC tissues and was significantly associated with TNM stage, vascular invasion, differentiation and AJCC stage. Univariate and multivariate Cox analyses confirmed that KLK8 is a significant independent prognostic factor for both DFS and OS. Cell function assays also indicated that KLK8 could facilitate CRC cell proliferation, migration and invasion in vitro. In conclusion, elevated KLK8 expression was correlated with the progression of CRC and is a potential independent prognostic indicator for CRC.

Genomic and transcriptomic analysis of imatinib resistance in gastrointestinal stromal tumors

Gastrointestinal stromal tumors represent the most common mesenchymal tumor of the digestive tract, driven by gain‐of‐function mutations in KIT. Despite its proven benefits, half of the patients treated with imatinib show disease progression within 2 years due to secondary resistance mutations in KIT. It remains unclear how the genomic and transcriptomic features change during the acquisition of imatinib resistance. Here, we performed exome sequencing and microarray transcription analysis for four imatinib‐resistant cell lines and one cell line briefly exposed to imatinib. We also performed exome sequencing of clinical tumor samples. The cell line briefly exposed to imatinib exhibited few single‐nucleotide variants and copy‐number alterations, but showed marked upregulation of genes related to detoxification and downregulation of genes involved in cell cycle progression. Meanwhile, resistant cell lines harbored numerous genomic changes: amplified genes related to detoxification and deleted genes with cyclin‐dependent kinase activity. Some variants in the resistant samples were traced back to the drug‐sensitive samples, indicating the presence of ancestral subpopulations. The subpopulations carried variants associated with cell death. Pre‐existing cancer cells with genetic alterations promoting apoptosis resistance may serve as a basis whereby cancer cells with critical mutations, such as secondary KIT mutations, can establish full imatinib resistance. © 2017 The Authors Genes, Chromosomes and Cancer Published by Wiley Periodicals, Inc.

Expression of Human Kallikreins 4, 8, 10, 11 and 13 in Pleomorphic Adenomas and Mucoepidermoid Carcinomas

BACKGROUND

In cancers of prostate, breast, oropharynx, lung, hypopharynx and skin, human tissue kallikreins has been demonstrated as a main role in these problems. There are many research works in which some human tissue kallikreins are expressed in salivary glands. In the present study, the main goal was to determine expression of human tissue kallikreins 4, 8, 10, 11 and 13 in pleomorphic adenomas and mucoepidermoid carcinomas.

METHODS

Sixty-six specimens (45 cases of pleomorphic adenomas and 21 cases mucoepidermoid carcinomas) were selected for final analysis by immunohistochemistry. For doing association test, clinical parameters obtained from the patients' medical charts, which included age, gender were used and the nonparametric tests employed for statistical analyses.

RESULTS

The expression of human kallikreins 4, 8, 11 and 13 was more prominent in benign and malignant tumors compared to that in normal tissues and the difference was significant. In addition, the expression of human kallikreins 4, 8, 10 and 11 in malignant tumors was more than that in benign tumors, with statistically significant differences.

CONCLUSION

The differences in the levels of human kallikreins 4, 8, 11 and 13 suggest that kallikreins may benefit in determining tumor behavior of salivary gland tumors.

Functional Histology of Salivary Gland Pleomorphic Adenoma: An Appraisal

The complex microstructure of salivary gland pleomorphic adenoma is examined in relation to function. Events related to secretion of macromolecules and absorption, responses to the altered microenvironment and controversies concerning epithelial-mesenchymal transition versus modified myoepithelial differentiation are explored. Their effects on tumor cell phenotypes and arrangements are emphasized. Heterotopic differentiation and attempts at organogenesis are also considered. The approach allows interpreting microstructure independently of histogenetic perceptions, envisaging the tumor cells as a continuum, endorsing luminal structures as the principal components, and defining pleomorphic adenoma as a benign epithelial tumour characterized by variable epithelial-mesenchymal transition, secretion/differentiation and metaplasia.

Kallikrein-related peptidase 10 expression in salivary gland tissues and tumours

OBJECTIVES

Kallikrein-related peptidase 10 (KLK10) has been implicated in the development of several types of cancer. The purpose of this study was to analyze the expression of KLK10 in 3 types of salivary gland tumour and normal salivary glands.

MATERIALS AND METHODS

A standard immunoperoxidase staining technique was used to assess the immunoexpression profile of KLK10 in normal salivary glands and 3 types of salivary gland tumour: pleomorphic adenoma, adenoid cystic carcinoma and mucoepidermoid carcinoma.

RESULTS

Pleomorphic adenomas showed significantly lower KLK10 levels than control tissues. Neither of the malignant tumours (adenoid cystic carcinoma and mucoepidermoid carcinoma) showed a significant alteration in the immunoreactive scores of KLK10 in comparison with the normal salivary gland tissues. KLK10 immunoreactive scores were comparable in adenoid cystic carcinoma and mucoepidermoid carcinoma. Pleomorphic adenoma had significantly lower levels of KLK10 than mucoepidermoid carcinoma.

CONCLUSIONS

The finding of lower KLK10 levels in pleomorphic adenoma suggests aberrant expression in a tumour that develops primarily from myoepithelial cells. A kallikrein cascade may play a role in the development and/or outcome of some salivary gland tumours.