Targeting kallikrein-related peptidases in prostate cancer

Introduction: Novel therapeutic compounds are needed for prostate cancer (CaP), given the limitations of already used drugs and the disease’s mortality, often attributed to castrate resistance. Tissue kallikrein and kallikrein-related peptidases (KLKs) form a family of serine proteases aberrantly expressed and broadly implicated in human malignancies. In CaP, KLKs participate in the promotion of cell proliferation, extracellular matrix degradation, tumour cell invasion and metastasis. Areas covered: This review discusses the different ways of inhibiting, modulating and exploiting KLK activity and/or expression as emerging CaP therapeutics. KLKs are targeted by diverse naturally occurring substances, including proteinaceous inhibitors, low-molecular-weight peptides and Zn2+. Synthetic KLK inhibitors include protein/peptide-based inhibitors and small molecules. A re-engineered serpin-based KLK inhibitor is under evaluation in first-in-human trials as a CaP therapeutic, whereas additional potent and selective KLK inhibitors with relevance to CaP have been synthesized. KLK3-activated pro-drugs have entered Phase I and Phase II clinical trials as therapeutics for prostate tumours. The KLK3-based PROSTVAC vaccine is evaluated in Phase III clinical trials. Targeting KLK expression via RNA interference methods could represent another promising therapeutic approach for CaP. Expert opinion: Apart from their immense biomarker potential, KLKs also hold promise as the basis of novel CaP therapeutics

Downregulation and Prognostic Performance of MicroRNA 224 Expression in Prostate Cancer

The extensive use of prostate-specific antigen as a general prostate cancer biomarker has introduced the hazards of overdiagnosis and overtreatment. Recent studies have revealed the immense biomarker capacity of microRNAs (miRNAs) in prostate cancer. The aim of this study was to analyze the expression pattern of miR-224, a cancer-related miRNA, in prostate tumors and investigate its clinical utility

Clinical relevance of the deregulated kallikrein-related peptidase 8 mRNA expression in breast cancer: a novel independent indicator of disease-free survival

Examining for new BC biomarkers has proven that kallikrein-related peptidase (KLK) family members represent promising serum and/or tissue molecular tools for early diagnosis, effective prognosis, and treatment monitoring of patients. The aim of this study was to investigate, the previously unexplored, prognostic significance of KLK8 in BC. KLK8 mRNA expression was quantitatively analyzed in 150 cancerous and 100 corresponding normal breast tissue specimens via a SYBR Green-based Real-Time PCR methodology. Expression data and patients’ clinicopathological parameters were used for extensive biostatistical analyses, including internal validation. KLK8 mRNA expression was significantly downregulated in the cancerous tissue part relative to the non-cancerous counterpart (P\0.001), in the majority of the paired breast tissue samples. KLK8 expression was associated with advanced TNM stage (P = 0.019) and positive nodal status involvement (P = 0.044). Triple negative (TNBC) and HER2 overexpressing tumors exhibited higher KLK8 expression levels (P\0.001), compared to Luminal A and B molecular subtypes. Kaplan–Meier survival curve analysis revealed that BC patients with high KLK8 expression had significantly shorter disease-free survival (DFS) intervals (P\0.001) compared to those belonging in the KLK8-low expression group. Cox univariate analysis confirmed the association between KLK8 expression, analyzed as a continuous variable, and poor patients’ outcome (Hazard ratio [HR] = 3.28, P\0.001). Most importantly, multivariate analysis showed that KLK8 expression is a strong and independent predictor of adverse DFS in BC ([HR] = 2.74; P = 0.002). Our results show that KLK8 mRNA expression is associated with aggressive tumor characteristics and it can serve as a novel independent biomarker of unfavorable prognosis for BC patients

Loss of miR-378 in prostate cancer, a common regulator of KLK2 and KLK4, correlates with aggressive disease phenotype and predicts the short-term relapse of the patients

A large number of prostate cancer (PCa) patients receive treatment without significant benefits, strengthening the need for accurate prognosis, which can be supported by the study of miRNAs. In silico specificity analysis was performed for the identification of miRNAs able to regulate KLK2 and KLK4 expression. Total RNA was extracted from prostate tissues obtained from PCa and benign prostate hyperplasia patients. Thereafter, RNA was polyadenylated and reverse transcribed to cDNA, which was used for qPCR analysis. miR-378 was predicted to target both KLK2 and KLK4 and downregulated levels detected in PCa patients (p = 0.050). The reduction of miR-378 was correlated with higher Gleason score (p = 0.018), larger diameter tumors (p = 0.034), and elevated serum PSA (p = 0.006). Regarding prognosis, miR-378 was able to improve risk stratification according to Gleason score or tumor stage, while higher risk to recur highlighted for the patients expressing lower miR-378 levels. Finally, the loss of miR-378 was able to predict the short-term relapse of ‘high’- and ‘very high’- recurrence-risk patients, independent of Gleason score, tumor stage, PSA, and age as indicated by Kaplan-Meier survival curves (p = 0.030) and multivariate Cox regression analysis (p = 0.018). In conclusion, loss of miR-378 expression increases the risk for PCa progression and relapse, despite active treatment

Prognostic and predictive biomarkers in prostate cancer

Prostate cancer (PCa) is one of the leading causes of cancer death among males, especially in more developed countries. Diagnosis is often achieved at an early stage of the disease with prostate biopsy, following a screening test showing elevated serum levels of prostate-specific antigen or a positive digital rectal examination. Early detection of PCa has led to a substantial decline in the number of metastatic patients. However, the prostate-specific antigen screening test has proved to be a double-edged sword so far, as it also accounts for PCa overdiagnosis. Due to the variability of PCa features, accurate prognosis of PCa patients is very important for determining treatment options. Therefore, this review focuses on the most promising prognostic and predictive biomarkers in PCa, which are likely to play a pivotal role, alone or in panels, in the personalized medicine era that has recently emerged

The loss of the tumour-suppressor miR-145 results in the shorter disease-free survival of prostate cancer patients

Background: Prostate cancer (PCa) is characterised by great heterogeneity of the disease progression rate. Tumours range from insignificant and not life threatening to high risk for relapse ones. Consequently, a large number of patients undergo unnecessary treatment. miR-145 is a well-documented tumour suppressor and its expression, which is regulated by the p53 pathway, has been found to be decreased in the majority of human malignancies. The aim of our study was to evaluate the clinical utility of miR-145 for the prognostication of PCa. Methods: Total RNA was isolated from 137 prostate tissue specimens obtained from 73 radical prostatectomy-treated PCa patients and 64 transurethral- or open prostatectomy-treated benign prostate hyperplasia (BPH) patients. Following polyadenylation and reverse transcription, miR-145 levels were determined by quantitative real-time PCR assay, using SNORD48 (RNU48) for normalisation purposes. Results: Downregulated miR-145 expression was found in PCa compared with BPH patients. The reduction of miR-145 expression in PCa was correlated with higher Gleason score, advanced clinical stage, larger tumour diameter and higher prostate-specific antigen (PSA) and follow-up PSA levels. In addition, higher risk for biochemical recurrence and significantly shorter disease-free survival (DFS) was found for the PCa patients expressing lower miR-145. Focusing on ‘low- and intermediate-recurrence risk’ PCa patients, miR-145 loss was revealed to be a reliable predictor of biochemical relapse and poor DFS independent from Gleason score, clinical stage, PSA and patients’ age. Conclusion: The loss of the tumour-suppressor miR-145 increases the risk for disease progression and predicts the poor survival of PCa patients

Quantitative expression analysis of the apoptotic gene BCL2L12 in breast cancer: association with clinical and molecular prognostic parameters

Apoptosis is a highly orchestrated, genetically regulated form of cell death, the impairment of which is crucial in breast cancer (BC) development and progression. BCL2L12, a member of the BCL2 family of apoptosis-related genes, has been studied in various malignancies, revealing its potential role as a tumor biomarker. It has been recently found that BCL2L12 is subjected to alternative splicing, resulting in the generation of 13 alternatively spliced variants. The aim of this study was the quantification of BCL2L12 splice variants 1 and 2 (v.1 and v.2) expression at the mRNA level and the assessment of their biomarker potential in BC

Codon 89 polymorphism in the human 5 α -reductase gene in primary breast cancer

The enzyme human steroid 5-α reductase type II (SRD5A2) and androgen receptor (AR) are critical mediators of androgen action, suggesting a potential role in hormonally related cancers. The SRD5A2 gene harbours two frequent polymorphic sites, one in the coding region, at codon 89 of exon 1, where valine is substituted by leucine (V89L) and the other in the 3′ untranslated region (3′ UTR) where a variable number of dinucleotide TA repeat lengths exists. The V89L polymorphism is known to alter the activity of this enzyme. In the present study we examined 144 sporadic breast tumours from Italian patients for the V89L and TA polymorphisms by sequence and fragment analysis, respectively. Tumour extract prostate specific antigen (PSA) concentration as well as a number of well-established clinical and pathological parameters were evaluated. The results show that 53% of the tumours were homozygous for VV alleles, 37% were heterozygous for VL alleles and 10% were homozygous for LL alleles. TA(0) repeats were found in tumours with VV, LL and VL genotypes. TA(9) repeats were only found in VV homozygotes and were totally absent from either LL homozygotes or VL heterozygotes. PSA expression was significantly elevated in tumours with VV genotype. The presence of LL alleles in breast tumours is associated with earlier onset and shorter disease-free (RR = 2.65;P = 0.013) and overall survival (RR = 3.06;P = 0.014) rates. The VV genotype is associated with a more favourable prognosis. Our study suggests that the polymorphism in codon 89 of exon 1 of the human 5α-reductase gene is related with TA repeat genotypes, PSA expression and breast cancer prognosis. More specifically, we found that the LL genotype is also associated with earlier onset and more aggressive forms of breast cancer. Long-term-outcome studies are needed to investigate the relevance of this polymorphism to breast cancer susceptibility. © 2001 Cancer Research Campaign http://www.bjcancer.co

BAX (BCL2-associated X protein)

Review on BAX (BCL2-associated X protein), with data on DNA, on the protein encoded, and where the gene is implicated