Downregulated KLK13 expression in bladder cancer highlights tumor aggressiveness and unfavorable patients' prognosis

Kallikrein-related peptidase 13 expression and clinicopathological features in lung squamous cell carcinoma

Lung squamous cell carcinoma (LSCC) is associated with poor prognosis. Molecular targeting drugs have been demonstrated to be effective for lung adenocarcinoma; however, they are often not effective for LSCC. Kallikrein-related peptidase 13 (KLK13) expression enhances the malignancy of lung adenocarcinoma; however, its expression and crucial role in LSCC remain largely unknown. The present study examined the relationship between the KLK13 expression and clinicopathological features of LSCC. A total of 94 patients diagnosed with LSCC who underwent lobectomy, segmentectomy or wedge resection were selected. KLK13 expression was evaluated through immunostaining of formalin-fixed paraffin-embedded sections of surgical specimens. Of the 94 LSCC samples, 70 exhibited no KLK13 expression, while the remaining 24 exhibited ectopic expression. KLK13 expression in tumors was focal and restricted to the cytoplasm of keratinized cells. LSCC cases were classified into KLK13-negative and KLK13-positive groups, and KLK13 expression was positively associated with E-cadherin expression (P=0.0143). Associations between KLK13 expression and keratinization (P=0.0052) or absence of lymphatic vessel invasion (P=0.0603) were observed; however, these trends did not reach statistical significance. The present findings indicated that KLK13 expression in keratinized LSCC may have a protective role in lymphatic vessel invasion of LSCC, which suggests its significance for therapeutic applications against LSCC.

Evaluation of the Small Heat Shock Protein Family Members HSPB2 and HSPB3 in Bladder Cancer Prognosis and Progression

Bladder cancer (BlCa) represents the sixth most commonly diagnosed type of male malignancy. Due to the clinical heterogeneity of BlCa, novel markers would optimize treatment efficacy and improve prognosis. The small heat shock proteins (sHSP) family is one of the major groups of molecular chaperones responsible for the maintenance of proteome functionality and stability. However, the role of sHSPs in BlCa remains largely unknown. The present study aimed to examine the association between HSPB2 and HSPB3 expression and BlCa progression in patients, and to investigate their role in BlCa cells. For this purpose, a series of experiments including reverse transcription-quantitative PCR, Western blotting, MTT assay and flow cytometry were performed. Initial analyses revealed increased vs. human transitional carcinoma cells, expression levels of the HSPB2 and HSPB3 genes and proteins in high grade BlCa cell lines. Therefore, we then evaluated the clinical significance of the HSPB2 and HSPB3 genes expression levels in bladder tumor samples and matched adjusted normal bladder specimens. Total RNA from 100 bladder tumor samples and 49 paired non-cancerous bladder specimens were isolated, and an accurate SYBR-Green based real-time quantitative polymerase chain reaction (qPCR) protocol was developed to quantify HSPB2 and HSPB3 mRNA levels in the two cohorts of specimens. A significant downregulation of the HSPB2 and HSPB3 genes expression was observed in bladder tumors as compared to matched normal urothelium; yet, increased HSPB2 and HSPB3 levels were noted in muscle-invasive (T2-T4) vs. superficial tumors (TaT1), as well as in high-grade vs. low-grade tumors. Survival analyses highlighted the significantly higher risk for post-treatment disease relapse in TaT1 patients poorly expressing HSPB2 and HSPB3 genes; this effect tended to be inverted in advanced disease stages (muscle-invasive tumors) indicating the biphasic impact of HSPB2, HSPB3 genes in BlCa progression. The pro-survival role of HSPB2 and HSPB3 in advanced tumor cells was also evident by our finding that HSPB2, HSPB3 genes expression silencing in high grade BlCa cells enhanced doxorubicin toxicity. These findings indicate that the HSPB2, HSPB3 chaperone genes have a likely pro-survival role in advanced BlCa; thus, they can be targeted as novel molecular markers to optimize treatment efficacy in BlCa and to limit unnecessary interventions.

Analysis of urinary kallikrein-related peptidase 13 for monitoring bladder cancer

BACKGROUND

Bladder cancer (BC) is one of the 10 most common types of cancer worldwide, with approximately 550,000 new cases each year. Early detection and appropriate diagnosis are important factors in successful treatment of the disease.

MATERIAL AND METHODS

We used specific fluorogenic substrate for the quantitative determination of urine kallikrein 13 (KLK13) activity in healthy (n = 15) and BC (n = 54) patients. The proteolytic activity in individual urine samples was determined by fluorescence measurements. Then, immunoenzymatic analyses (ELISA, Western blot) were performed to confirm the presence of KLK13 in the tested samples.

RESULTS

Urine samples from patients with G2 and G3 grade BC contained proteolytically active KLK13, as confirmed by kinetic analysis and immunochemical detection. KLK13 was not detected in the urine of patients with G1 grade BC.

DISCUSSION

Previous clinical study reveals the KLK13 significance for BC prognosis as increased KLK13 expression was highlighted in bladder tumours compared to normal adjacent tissues. Our findings correlate to the report. KLK13 activity was confirmed in BC patients with G2 and G3 stage of disease development.

CONCLUSIONS

Using specific chromogenic/fluorogenic peptides could be useful for the non-invasive disease monitoring of BC progress.

Risk stratification of cutaneous melanoma reveals carcinogen metabolism enrichment and immune inhibition in high-risk patients

Cutaneous melanoma (CM) is the most lethal form of skin cancer. Risk assessment should facilitate stratified surveillance and guide treatment selection. Here, based on the mRNA-seq data from 419 CM patients in the Cancer Genome Atlas (TCGA), we developed a prognostic 21-gene signature to distinguish the outcomes of high- and low-risk patients, which was further validated in two external cohorts. The signature achieved a higher C-index as compared with other known biomarkers and clinical characteristics in both the TCGA and validation cohorts. Notably, in high-risk patients the expression levels of three driver genes, BRAF, NRAS, and NF1 in the MAPK pathway, were lower but exhibited a stronger positive correlation as compared with low-risk patients. Moreover, the genes involved in nicotinamide adenine dinucleotide metabolism were negatively correlated with the expression of BRAF in the high-risk group. Function analysis revealed that the upregulated genes in the high-risk group were enriched in the cytochrome P450-mediated metabolism of chemical carcinogens. Furthermore, the low-risk group had high levels of gamma delta T cells infiltration, while regulatory T cells were accumulated in the high-risk group. The present study offers a promising new prognostic signature for CM, and provides insight into the mechanisms of melanoma progression.

Cancer-related proteins in serum are altered in workers occupationally exposed to polycyclic aromatic hydrocarbons: a cross-sectional study

Exposure to some polycyclic aromatic hydrocarbons (PAH) increases the risk of cancer and is common particularly for workers in occupations such as chimney sweeping. In exposed workers, screening of early cancer-related markers provides important information to identify individuals at risk. Here, we aimed to elucidate the associations between PAH exposure and serum levels of cancer-related proteins in 118 chimney sweeps and 126 occupationally unexposed controls, all non-smoking males from Sweden. Monoydroxylated metabolites of pyrene, phenanthrene, benzo[a]pyrene and benzo[a]anthracene were measured in urine using liquid chromatography coupled to tandem mass spectrometry and 90 cancer-related proteins were measured in serum using a proximity extension assay. Linear regression analysis adjusted for age and body mass index, and false discovery rate (FDR) identified 17 serum proteins that were differentially expressed (16 upregulated and 1 downregulated) in chimney sweeps compared with controls (FDR < 0.05). Concentrations of the peptidase kallikrein 13 (KLK13) showed significant positive associations with urinary concentrations of the PAH metabolites 3-hydroxybenzo[a]pyrene (3-OH-BaP) [B, 95% confidence interval (CI): 0.042, 0.008–0.076] and 3-hydroxybenzo[a]anthracene (3-OH-BaA) (B, 95% CI: 0.068, 0.002–0.134). Moreover, dose–response relationships were observed between KLK13 and 3-OH-BaP (trend test P = 0.027) and 3-OH-BaA (P = 0.035). Pathway and gene ontology analyses showed that cell movement, cell adhesion and cell migration were the predominant molecular functions associated with the top differentially expressed proteins. In conclusion, we found a number of putative cancer-related proteins differentially expressed in workers exposed to PAH. This warrants effective measure to reduce PAH exposure among workers as well as further investigation to confirm these findings.

Biomarkers predicting oncological outcomes of high-risk non-muscle-invasive bladder cancer

INTRODUCTION

The European Organization for Research and Treatment of Cancer (EORTC) and the Spanish Urological Club for Oncological Treatment (CUETO) scoring systems show limited accuracy for the prediction of disease recurrence and progression of non-muscle-invasive bladder cancer (NMIBC). This aspect is even more relevant in the category of HR NMIBC. Biomarkers might potentially help to further categorize the outcomes of these patients. Therefore, we sought to review the evidence available on tissue-based, urinary, and serum biomarkers for the prediction of recurrence, progression, and survival in HR NMIBC.

EVIDENCE ACQUISITION

A systematic literature review without time restrictions was performed using PubMed/EMBASE, Web of Science, SCOPUS, and the Cochrane Libraries. The search was filtered for articles in the English, Italian, German, French, and Spanish languages, involving patients with more than 18 years of age. Relevant papers on tissue-based, serum and urinary biomarkers related to the prediction of oncological outcomes for high-risk bladder cancer patients were included in the analyses.

EVIDENCE SYNTHESIS

Overall, 71 studies were eligible for inclusion in this review. The majority of the investigations performed so far focused on immunohistochemical analyses on tumoral tissue. Overall, p53 was the most studied biomarker, but results regarding its prognostic and predictive role were contradictory. Ki67 seems to be a promising biomarker in the prediction of recurrence. Recently, PD-L1 has been associated with the prediction of recurrence free survival and of treatment-refractory disease. Markers developed un urine samples are focused on commercially available kits, which currently do not unequivocally show strongly superior levels of accuracy to cytology. However, they have demonstrated to be potentially helpful in the prediction of recurrence. Blood-based biomarkers represent an emerging reality with promising future applications.

CONCLUSIONS

Despite a long history of attempts to discover accurate biomarkers predicting oncological outcomes for HR NMIBC, contradictory or uncertain findings render the adoption of this ancillary techniques in clinical practice still unlikely. Future attempts should be directed to the development of prospective trials and the definition of standardized cut-off levels to render findings worthy of comparison.

An eight-mRNA signature predicts the prognosis of patients with bladder urothelial carcinoma

Background

Bladder cancer is one of the most common cancers, and its histopathological type is mainly bladder urothelial carcinoma, accounting for about 90%. The prognostic biomarkers of bladder cancer are classified into clinical features biomarkers and molecular biomarkers. Nevertheless, due to the existence of individual specificity, patients with similar pathological characteristics still have great differences in the risk of disease recurrence. Therefore, it is often inaccurate to predict the survival status of patients based on clinical characteristic biomarkers, and a prognostic molecular biomarker that can grade the risk of bladder cancer patients is needed.

Methods

A total of three bladder urothelial carcinoma datasets were used in this study from the Cancer Genome Atlas database and Gene Expression Omnibus database. In order to avoid overfitting, all samples were randomly divided into one training set and three validation sets, which were used to construct and test the prognostic biomarker model of bladder urothelial carcinoma. Univariate and multivariate Cox regression were used to screen candidate mRNAs and construct prognostic biomarkers model. Kaplan-Meier survival analysis and the receiver operating characteristic (ROC) curve were used to evaluate the predictive performance of the model.

Results

A prognostic biomarker model of bladder urothelial carcinoma combining with eight mRNA was constructed. Kaplan-Meier analyses indicated that a significant difference in the survival time of patients between the high-risk and the low-risk group. The area under the ROC curve were 0.632 (95% confidence interval (CI) [0.541-0.723]), 0.693 (95% CI [0.601-0.784]) and 0.686 (95% CI [0.540-0.831]) when the model was used to predict the patient's survival time in three validation datasets. The model showed high accuracy and applicability.

The miRNA-kallikrein interaction: a mosaic of epigenetic regulation in cancer

The kallikrein-related peptidases (KLKs) constitute a family of 15 highly conserved serine proteases with trypsin- and chymotrypsin-like activities. Dysregulated expression and/or aberrant activation of KLKs has been linked to various pathophysiological processes, including cancer. Many KLKs have been identified as potential cancer biomarkers. microRNAs (miRNAs) are a class of small non-coding RNAs that regulate gene expression by pairing to the 3' untranslated region (UTR) of complimentary mRNA targets. miRNAs are dysregulated in many cancers, including prostate, kidney and ovarian cancers. Several studies have shown that miRNAs are involved in the post-transcriptional regulation of KLKs. However, recent evidence suggests that miRNAs can also act as downstream effectors of KLKs. In this review, we provide an update on the epigenetic regulation of KLKs by miRNAs. We also present recent experimental evidence that supports the regulatory role of KLKs on miRNA networks. The potential diagnostic and therapeutic applications of miRNA-kallikrein interactions are also discussed.

MicroRNA-3162-5p-Mediated Crosstalk between Kallikrein Family Members Including Prostate-Specific Antigen in Prostate Cancer

BACKGROUND

MicroRNAs mediate biological processes through preferential binding to the 3' untranslated region (3' UTR) of target genes. Studies have shown their association with prostate cancer (PCa) risk through single-nucleotide polymorphisms (SNPs), known as miRSNPs. In a European cohort, 22 PCa risk-associated miRSNPs have been identified. The most significant miRSNP in the 3' UTR of Kallikrein-related peptidase 3 (KLK3) created a binding site for miR-3162-5p. Here we investigated the miR-3162-5p-KLK interaction and the clinical implication of miR-3162-5p in PCa.

METHODS

We tested the role of miR-3162-5p in PCa etiology using IncuCyte live-cell imaging and anchorage-independent growth assays. The effect of miR-3162-5p on KLK and androgen receptor (AR) expression was measured by RT-quantitative (q)PCR and target pulldown assays. KLK3 proteolytic activity was determined by DELFIA^® immunoassay. Mass spectrometry identified pathways affected by miR-3162-5p. miR-3162-5p expression was measured in clinical samples using RT-qPCR.

RESULTS

miR-3162-5p affected proliferation, migration, and colony formation of LNCaP cells by regulating the expression of KLK2-4 and AR by direct targeting. KLK3 protein expression was regulated by miR-3162-5p consistent with lower KLK3 proteolytic activity observed in LNCaP-conditioned media. KLK/AR pulldown and mass spectrometry analysis showed a potential role of miR-3162-5p in metabolic pathways via KLK/AR and additional targets. Increased miR-3162-5p expression was observed in prostate tumor tissues with higher Gleason grade.

CONCLUSIONS

Our study provides an insight into possible involvement of miR-3162-5p in PCa etiology by targeting KLKs and AR. It highlights clinical utility of miR-3162-5p and its interactive axis as a new class of biomarkers and therapeutic targets for PCa.

Functional proteomic profiling reveals KLK13 and TMPRSS11D as active proteases in the lower female reproductive tract

Background: Cervical-vaginal fluid (CVF) hydrates the mucosa of the lower female reproductive tract and is known to contain numerous proteases. The low pH of CVF (4.5 or below in healthy women of reproductive age) is a uniquely human attribute and poses a challenge for the proteolytic functioning of the proteases identified in this complex biological fluid. Despite the abundance of certain proteases in CVF, the proteolytic activity and function of proteases in CVF is not well characterized.

Methods: In the present study, we employed fluorogenic substrate screening to investigate the influence of pH and inhibitory compounds on the proteolytic activity in CVF. Activity-based probe (ABP) proteomics has evolved as a powerful tool to investigate active proteases within complex proteomes and a trypsin-specific ABP was used to identify active proteases in CVF.

Results: Serine proteases are among the most abundant proteins in the CVF proteome. Labeling human CVF samples with the trypsin-specific ABP revealed serine proteases transmembrane protein serine 11D and kallikrein-related peptidase 13 as active proteases in CVF. Furthermore, we demonstrated that the proteolytic activity in CVF is highly pH-dependent with an almost absolute inhibition of trypsin-like proteolytic activity at physiological pH levels.

Conclusions: These findings provide a framework to understand proteolytic activity in CVF. Furthermore, the present results provide clues for a novel regulatory mechanism in which fluctuations in CVF pH have the potential to control the catalytic activity in the lower female reproductive tract.

Kallikrein-related peptidases and associated microRNAs as promising prognostic biomarkers in gastrointestinal malignancies

Gastrointestinal (GI) malignancies represent a wide spectrum of diseases of the GI tract and its accessory digestive organs, including esophageal (EC), gastric (GC), hepatocellular, pancreatic (PC) and colorectal cancers (CRC). Malignancies of the GI system are responsible for nearly 30% of cancer-related morbidity and approximately 40% of cancer-related mortality, worldwide. For this reason, the discovery of novel prognostic biomarkers that can efficiently provide a better prognosis, risk assessment and prediction of treatment response is an imperative need. Human kallikrein-related peptidases (KLKs) are a subgroup of trypsin and chymotrypsin-like serine peptidases that have emerged as promising prognosticators for many human types of cancer, being aberrantly expressed in cancerous tissues. The aberrant expression of KLKs in human malignancies is often regulated by KLK/microRNAs (miRNAs) interactions, as many miRNAs have been found to target KLKs and therefore alter their expression levels. The biomarker utility of KLKs has been elucidated not only in endocrine-related human malignancies, including those of the prostate and breast, but also in GI malignancies. The main purpose of this review is to summarize the existing information regarding the prognostic significance of KLKs in major types of GI malignancies and highlight the regulatory role of miRNAs on the expression levels of KLKs in these types of cancer.

Diagnostic and prognostic biomarker potential of kallikrein family genes in different cancer types

Purpose

The aim of this study was to compare and contrast the expression of all members of the Kallikrein (KLK) family of genes across 15 cancer types and to evaluate their utility as diagnostic and prognostic biomarkers.

Results

Severe alterations were found in the expression of different Kallikrein genes across various cancers. Interestingly, renal clear cell and papillary carcinomas have similar kallikrein expression profiles, whereas, chromophobe renal cell carcinoma has a unique expression profile. Several KLK genes have excellent biomarker potential (AUC > 0.90) for chromophobe renal cell carcinoma (KLK2, KLK3, KLK4, KLK7, KLK15), renal papillary carcinoma (KLK1, KLK6, KLK7), clear cell renal cell carcinoma (KLK1, KLK6), thyroid carcinoma (KLK2, KLK4, KLK13, KLK15) and colon adenocarcinoma (KLK6, KLK7, KLK8, KLK10). Several KLK genes were significantly associated with mortality in clear cell renal cell carcinoma (KLK2: HR = 1.69; KLK4: HR = 1.63; KLK8: HR = 1.71; KLK10: HR = 2.12; KLK11: HR = 1.76; KLK14: HR = 1.86), papillary renal cell carcinoma (KLK6: HR = 3.38, KLK7: HR = 2.50), urothelial bladder carcinoma (KLK5: HR = 1.89, KLK6: HR = 1.71, KLK8: HR = 1.60), and hepatocellular carcinoma (KLK13: HR = 1.75).

Methods

The RNA-seq gene expression data were downloaded from The Cancer Genome Atlas (TCGA). Statistical analyses, including differential expression analysis, receiver operating characteristic curves and survival analysis (Cox proportional-hazards regression models) were performed.

Conclusions

A comprehensive analysis revealed the changes in the expression of different KLK genes associated with specific cancers and highlighted their potential as a diagnostic and prognostic tool.

Expression of kallikrein-related peptidase 13 is associated with poor prognosis in esophageal squamous cell carcinoma

OBJECTIVE

Our previous differential transcriptome analysis between a paired specimen of normal and esophageal squamous cell carcinoma (ESCC) tissues found aberrant expression of kallikrein-related peptidase 13 (KLK13) in tumors. In this study, we evaluated the expression of KLK13 in many ESCC cases in relation with clinical features, and the prognosis.

METHODS

Eighty-eight ESCC cases were subjected to immunohistological staining for KLK13 and classified into KLK13-negative and KLK13-positive groups. Difference of clinical features and the prognosis between the groups was analyzed.

RESULTS

In normal esophageal mucosa, KLK13 expression was evident but limited in the stratum granulosum in all cases. By contrast, only 27 of 88 ESCC samples showed KLK13 expression, whereas the remaining 61 tumors showed no KLK13 expression. The KLK13-positive group was significantly associated with pT classification (deeper tumor invasions; P = 0.0282), pN classification (lymph node metastasis; P = 0.0163), and advanced TNM stage (P = 0.0198). In KLK13-positive samples, KLK13-expressing cells often expressed Ki67, a proliferation marker, unlike normal mucosa, in which Ki67-expressing cells were limited to the basal layer and did not express KLK13. Compared with patients with KLK13-negative group, KLK13-positive group showed poorer postoperative prognosis.

CONCLUSION

Relatively high levels of KLK13 expression in ESCC were associated with cell proliferation and correlated with tumor progression, advanced cancer stage, and poor prognosis.

Downregulation of KLK13 promotes the invasiveness and metastasis of oesophageal squamous cell carcinoma

KLK13 downregulation occurs in tumour tissues in comparison with adjacent normal tissues from patients with oesophageal squamous cell carcinoma (OSCC). KLK13 mRNA levels were tested in OSCC tumour tissues and adjacent noncancerous tissues from 138 patients. In addition, the correlation between KLK13 mRNA levels and OSCC clinicopathologic features was analysed. KLK13 mRNA levels decreased notably in tumour tissues compared with those in adjacent noncancerous tissues. And decreased KLK13 mRNA levels indicated significant correlations with higher tumour grade, elevated TNM (UICC, 2009) stage classification, deeper infiltration and more lymph node metastases. And thus KLK13 may be a promising diagnostic marker. Decreased KLK13 mRNA levels also correlate with poor survival, which indicates that KLK13 mRNA expression may be a potential prognostic marker, although it could not be an independent prognostic factor by multivariate analysis. In vitro experiments of the OSCC cell lines KYSE150 and KYSE450 demonstrated that overexpression of KLK13 inhibits cell invasion and migration. Thus, KLK13 is a unique novel molecule useful for monitoring OSCC progression. Full elucidation of the role of KLK13 in OSCC may reveal avenues for investigating the molecule's functional potential as a novel therapeutic drug for targeting OSCC.