Genomics of prostate cancer: Is there anything to „translate”?

Prospects of Treating Prostate Cancer through Apalutamide: A Mini-Review

BACKGROUND

Prostate cancer is considered the second most diagnosed cancer, and one of the most common causes of death from cancer in men. Apalutamide is an effective, safe, and well-tolerated agent used for the treatment of men with non-metastatic castration-resistant prostate cancer (nmCRPC) and metastatic hormone-naive prostate cancer (mHNPC). Androgen receptor signaling is a leading factor that drives these prostate tumors. USFDA has approved apalutamide on 14 February 2018 as an agent that targets androgen receptor signaling through inhibition causing significant improvement in metastasis-free survival in patients with prostate cancer. <P> Objective: In this review, various aspects related to apalutamide have been summarized which involve the mechanism of action, chemistry, synthesis, pharmacokinetics, pharmacodynamics, adverse reactions, and safety parameters. <P> Methods: The literature was thoroughly searched in the relevant databases to identify studies published in this field during recent years. Special attention has been given to apalutamide clinical trials phases and its promising future as one of the first-line agents for the treatment of patients with advanced prostate cancer. <P> Results: Ongoing trials are progressing for apalutamide monotherapy and also for its combinations in other disease settings. The expected results of such trials will shape the future scenario of prostate cancer therapy. <P> Conclusion: This review article has highlighted different aspects of Apalutamide like its mechanism of action, adverse effects, pharmacokinetics, pharmacodynamics, clinical trials among others. The contents of this article should make an excellent read for prospective researchers in this field.

Co-delivery of miRNA-15a and miRNA-16-1 using cationic PEGylated niosomes downregulates Bcl-2 and induces apoptosis in prostate cancer cells

OBJECTIVE

Tumor suppressor miRNAs, miR-15a and miR-16-1, with high-specificity and oncogenic targeting of Bcl-2, can target tumor tissues. Disadvantages of the clinical application of free miRNAs include poor cellular uptake and instability in plasma, which can be partially improved by using nanocarriers to deliver anti-cancer agents to the tumor cell.

METHOD

In this study, cationic niosomes were designed and optimized with the specific formulation. Then, the physical characteristics, the cytotoxicity, the impact of transfected miRNAs on the expression of the Bcl-2 gene, and the apoptosis rate of the different formulation into prostate cancer cell were determined.

RESULTS

The optimum formulation containing tween-60: cholesterol: DOTAP: DSPE-PEG2000 at 70:30:25:5 demonstrated that the vesicle size and zeta potentials were 69.7 nm and + 14.83 mV, respectively. Additionally, noisome-loaded miRNAs had higher toxicity against cancer cells comparing with free forms. The transfection of PC3 cells with the combination therapy of nanocarriers loaded of two miRNAs led to a significant decrease in the expression of the Bcl-2 gene and increased the degree of cell death in PC3 cells compared with other treatment groups, and the synergistic effects of co-delivery of miR-15a and miR-16-1 on prostate cancer cells were shown.

CONCLUSION

According to the results, it seems the designed niosomes containing miR-15a and miR-16-1 can target the Bcl-2 gene and provide a cheap, applicable, cost-effective, and safe drug delivery system against prostate cancer.

Inhibition on JNK Mimics Silencing of Wnt-11 Mediated Cellular Response in Androgen-Independent Prostate Cancer Cells

Prostate cancer (PCa) is one of the most common cancers among men, and one of the leading causes of cancer death for men. The c-Jun N-terminal kinase (JNK) pathway is required for several cellular functions, such as survival, proliferation, differentiation, and migration. Wnt-11, a member of the Wnt family, has been identified for its upregulation in PCa; however, downstream signalling of Wnt-11 remains to be fully characterized. In this study, we investigated the role of the JNK pathway as a potential downstream factor for Wnt-11 signalling. For this purpose, LNCaP, DU145, and PC-3 PCa cells and normal epithelial PNT1A cells were treated with a specific JNK kinase inhibitor: JNKVIII. Our results showed that JNK inhibition decreased mitochondrial membrane potential and promoted cell death in a cell type-dependent manner. We found that JNK inhibition led to an increase in autophagy and prevented epithelial–mesenchymal transition (EMT) in independently growing androgen cells. JNK inhibition and the silencing of Wnt-11 showed similar responses in DU145 and PC-3 cells and decreased metastasis-related biomarkers, cell migration, and invasion. Overall, our results suggest that JNK signalling plays a significant role in the pathophysiology of PCa by mediating Wnt-11 induced signals. Our data highlights that both the JNK pathway and Wnt-11 could be a useful therapeutic target for the combinatory application of current PCa.

Genetic and molecular determinants of prostate cancer among Iranian patients: An update

Prostate cancer (PCa) is one of the most common age-related cancers among men. Various environmental and genetic factors are involved in the development and progression of PCa. In most cases, the primary symptoms of disease are not severe. Therefore, it is common for patients to be referred with severe clinical manifestations at advanced stages of disease. Since this malignancy is age related and Iran will face a significant increase in the number of seniors, it is expected that the prevalence of PCa among Iranian men will rise. PCa progression has been observed to be associated with genetic and ethnic factors. It may therefore be clinically useful to determine a panel of genetic markers, in addition to routine diagnostic methods, to detect tumors in the early stages. In the present review, we have summarized the reported genetic markers in PCa Iranian patients to pave the way for the determination of an ethnic specific genetic marker panel for the early detection of PCa. To understand the genetic and molecular biology of PCa among Iranians, we have categorized these genetic markers based on their cellular functions.

Exosomal microRNAs in liquid biopsies: future biomarkers for prostate cancer

Prostate cancer is the second most diagnosed cancer in males in the world. Plasma quantification of prostate-specific antigen substantially improved the early detection of prostate cancer, but still lacks the required specificity. Clinical management of prostate cancer needs advances in the development of new non-invasive biomarkers, ameliorating current diagnosis and prognosis and guiding therapeutic decisions. microRNAs (miRNAs) are a class of small non-coding RNAs that regulate gene expression at the post-transcriptional level. These miRNAs are expressed in the cells and are also present in cell-derived extracellular vesicles such as exosomes. Exosomes have been shown to act as mediators for cell to cell communication because of the regulatory functions of their content. High levels of exosomes are found in several body fluids from cancer patients and could be a potential source of non-invasive biomarkers. In this review, we summarize the diagnostic and prognostic utility of exosomal miRNAs in prostate cancer.

DNA alterations in the tumor genome and their associations with clinical outcome in prostate cancer

Although most prostate cancer (PCa) cases are not life-threatening, approximately 293 000 men worldwide die annually due to PCa. These lethal cases are thought to be caused by coordinated genomic alterations that accumulate over time. Recent genome-wide analyses of DNA from subjects with PCa have revealed most, if not all, genetic changes in both germline and PCa tumor genomes. In this article, I first review the major, somatically acquired genomic characteristics of various subtypes of PCa. I then recap key findings on the relationships between genomic alterations and clinical parameters, such as biochemical recurrence or clinical relapse, metastasis and cancer-specific mortality. Finally, I outline the need for, and challenges with, validation of recent findings in prospective studies for clinical utility. It is clearer now than ever before that the landscape of somatically acquired aberrations in PCa is highlighted by DNA copy number alterations (CNAs) and TMPRSS2-ERG fusion derived from complex rearrangements, numerous single nucleotide variations or mutations, tremendous heterogeneity, and continuously punctuated evolution. Genome-wide CNAs, PTEN loss, MYC gain in primary tumors, and TP53 loss/mutation and AR amplification/mutation in advanced metastatic PCa have consistently been associated with worse cancer prognosis. With this recently gained knowledge, it is now an opportune time to develop DNA-based tests that provide more accurate patient stratification for prediction of clinical outcome, which will ultimately lead to more personalized cancer care than is possible at present.

Study of NGEP expression pattern in cancerous tissues provides novel insights into prognostic marker in prostate cancer

AIM

The aim of this study was to produce a novel polyclonal antibody against extracellular domain of NGEP protein and explore its role in prognosis of prostate cancer.

MATERIALS & METHODS

Polyclonal antibodies against two peptides (NGEP-p1 and NGEP-p2) derived extracellular domains of NGEP were prepared and the intensity and distribution of NGEP expression analyzed in large series of prostate tissue specimens.

RESULTS

We found a significant inverse correlation between NGEP expression and prognostic features such as Gleason score, pathologic tumor stage and prostate-specific antigen level using anti-NGEP-p2 antibody.

CONCLUSION

The results indicate that the high level of expression could be associated with good prognosis in prostate cancer. However, additional studies are required to evaluate NGEP as an independent prognostic factor for prostate carcinoma.

Role of miRNA let-7 and its major targets in prostate cancer

Prostate cancer is worldwide the sixth leading cause of cancer related death in men thus early detection and successful treatment are still of major interest. The commonly performed screening of the prostate-specific antigen (PSA) is controversially discussed, as in many patients the prostate-specific antigen levels are chronically elevated in the absence of cancer. Due to the unsatisfying efficiency of available prostate cancer screening markers and the current treatment outcome of the aggressive hormone refractory prostate cancer, the evaluation of novel molecular markers and targets is considered an issue of high importance. MicroRNAs are relatively stable in body fluids orchestrating simultaneously the expression of many genes. These molecules are currently discussed to bear a greater diagnostic potential than protein-coding genes, being additionally promising therapeutic drugs and/or targets. Herein we review the potential impact of the microRNA let-7 family on prostate cancer and show how deregulation of several of its target genes could influence the cellular equilibrium in the prostate gland, promoting cancer development as they do in a variety of other human malignant neoplasias.

A 12-gene expression signature is associated with aggressive histological in prostate cancer: SEC14L1 and TCEB1 genes are potential markers of progression

The main challenge for clinical management of prostate cancer is to distinguish tumors that will progress faster and will show a higher tendency to recur from the more indolent ones. We have compared expression profiles of 18 prostate cancer samples (seven with a Gleason score of 6, eight with a Gleason score of 7, and three with a Gleason score of ≥8) and five nonneoplastic prostate samples, using the Affymetrix Human Array GeneChip Exon 1.0 ST. Microarray analysis revealed 99 genes showing statistically significant differences among tumors with Gleason scores of 6, 7, and ≥8. In addition, mRNA expression of 29 selected genes was analyzed by real-time quantitative RT-PCR with microfluidic cards in an extended series of 30 prostate tumors. Of the 29 genes, 18 (62%) were independently confirmed in the extended series by quantitative RT-PCR: 14 were up-regulated and 4 were down-regulated in tumors with a higher Gleason score. Twelve of these genes were differentially expressed in tumors with a Gleason score of 6 to 7 versus ≥8. Finally, IHC validation of the protein levels of two genes from the 12-gene signature (SEC14L1 and TCEB1) showed strong protein expression levels of both genes, which were statistically associated with a high combined Gleason score, advanced stage, and prostate-specific antigen progression. This set of genes may contribute to a better understanding of the molecular basis of prostate cancer. TCEB1 and SELC14L1 are good candidate markers for predicting prognosis and progression of prostate cancer.

Interrogating genomic and epigenomic data to understand prostate cancer

Major breakthroughs at the beginning of this century in high-throughput technologies have profoundly transformed biological research. Significant knowledge has been gained regarding our biological system and its disease such as malignant transformation. In this review, we summarize leading discoveries in prostate cancer research derived from the use of high-throughput approaches powered by microarrays and massively parallel next-generation sequencing (NGS). These include the seminal discovery of chromosomal translocations such as TMPRSS2-ERG gene fusions as well as the identification of critical oncogenes exemplified by the polycomb group protein EZH2. We then demonstrate the power of interrogating genomic and epigenomic data in understanding the plethora of mechanisms of transcriptional regulation. As an example, we review how androgen receptor (AR) binding events are mediated at multiple levels through protein-DNA interaction, histone and DNA modifications, as well as high-order chromatin structural changes.

Expression of two testis-specific genes, SPATA19 and LEMD1, in prostate cancer

BACKGROUND AND AIMS

Screening methods for early detection of prostate cancer have some limitations regarding specificity and sensitivity, so there is a continuing search to find new cancer biomarkers. Cancer-testis genes are a group of genes with expression almost limited to testis and different kinds of tumors. Since testis is an immune privileged site, if these genes are expressed in tumors, they can be immunogenic. We undertook this study to find new members of the cancer-testis gene family appropriate for cancer immunotherapy

METHODS

We analyzed the expression of six testis-specific genes called ODF1, ODF2, ODF3, ODF4, LEMD1 and SPATA19 in 30 prostate cancer and 25 benign prostate hyperplasia (BPH) samples by RT-PCR and restriction fragment length polymorphism (RFLP).

RESULTS

Of the prostate cancer samples, 10, 10, 23 and 40% showed ODF1, ODF2, LEMD1 and SPATA19 specific bands, respectively, but none of the BPH samples expressed any of these genes. The difference between prostate cancer and BPH groups for LEMD1 and SPATA19 expression was significant. Mean serum PSA level was significantly higher in patients expressing ODF2 than in the other patients.

CONCLUSIONS

ODF1, ODF2, SPATA19 and LEMD1 are members of cancer-testis gene family. In addition, LEMD1 and SPATA19 are putative cancer biomarkers and promising targets for active immunotherapy.

Interest in genetic testing among affected men from hereditary prostate cancer families and their unaffected male relatives

PURPOSE

The objective of this study was to evaluate potential sociodemographic, medical, psychosocial, and behavioral correlates of interest in genetic testing in men from hereditary prostate cancer families.

METHODS

Family members affected with prostate cancer (n = 559) and their unaffected male relatives (n = 370) completed a mailed survey. Multivariable logistic regression models were used to examine the association between potential correlates and interest in genetic testing for prostate cancer.

RESULTS

Forty-five percent of affected and 56% of unaffected men reported that they definitely would take a genetic test for prostate cancer. More affected men reported high levels of familiarity with genetic testing than unaffected men (46 vs. 25%). There were several variables that were significantly correlated with interest in either affected or unaffected men, but only age and familiarity with genetics were significant in both groups. After controlling for confounding variables, only familiarity remained a significant correlate in both groups.

CONCLUSIONS

The contrast between low levels of familiarity with genetics and high test interest among unaffected men highlights the need for increased educational efforts targeting hereditary prostate cancer families. Overall, results illuminated several novel characteristics of men from hereditary prostate cancer families that should be considered when developing future informed consent procedures or educational materials for prostate cancer genetic testing.

FGFR3 mutations in prostate cancer: association with low-grade tumors

Prostate cancer is the second cause of cancer-related death in men of the Western World. The role of FGFR3 and its abnormalities in prostate cancer are not known. FGFR3 mutations have been reported in some human tumors. Few studies have analyzed the mutations of FGFR3 in prostate tumors, and no mutations have been previously reported. Prevalence of FGFR3 somatic mutations was investigated in a series of prostate tumors. The presence of other tumors in these patients, including urothelial, skin, colon, and lung neoplasms, was recorded. Mutational analysis of exons 7, 10, and 15 of FGFR3 revealed 9 mutations in the 112 prostate tumors studied (8%). Most of them consisted of the missense change S249C. The prevalence of mutations in tumors with combined Gleason score=6 is 18% (8/45) compared to 3% (1/36) for tumors with grade=7, and 0% (0/31) for those with grade >or=8 and metastases (P=0.007). The frequency of FGFR3 mutations in autopsy and biopsy samples was 6 and 9%, respectively. The prevalence of FGFR3 mutations in prostate tumors from patients with only prostate cancer was 2% compared to 23% in prostate tumors from patients with other associated neoplasms (P=0.001). This is the first report of molecular changes of FGFR3 in prostate cancer. This gene does not seem to be central to the pathogenesis of prostate cancer, but it is significantly associated with a subgroup of low-grade prostate tumors, and with the finding of other tumors, mainly arising in bladder and skin.

Suitable reference genes for real-time PCR in human HBV-related hepatocellular carcinoma with different clinical prognoses

Background

Housekeeping genes are routinely used as endogenous references to account for experimental differences in gene expression assays. However, recent reports show that they could be de-regulated in different diseases, model animals, or even under varied experimental conditions, which may lead to unreliable results and consequently misinterpretations. This study focused on the selection of suitable reference genes for quantitative PCR in human hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) with different clinical outcomes.

Methods

We evaluated 6 commonly used housekeeping genes' expression levels in 108 HBV-related HCCs' matched tumor and non-tomor tissue samples with different clinical outcomes and 26 normal liver specimens by real-time PCR. The expression stability of the 6 genes was compared using the software programs geNorm and NormFinder. To show the impact of reference genes on data analysis, we took PGK1 as a target gene normalized by each reference gene, and performed one-way ANOVA and the equivalence test.

Results

With the geNorm and NormFinder software programs, analysis of TBP and HPRT1 showed the best stability in all tissue samples, while 18s and ACTB were less stable. When 18s or ACTB was used for normalization, no significant difference of PGK1 expression (p > 0.05) was found among HCC tissues with and without metastasis, and normal liver specimens; however, dramatically differences (p < 0.001) were observed when either TBP or the combination of TBP and HPRT1 were selected as reference genes.

Conclusion

TBP and HPRT1 are the most reliable reference genes for q-PCR normalization in HBV-related HCC specimens. However, the well-used ACTB and 18S are not suitable, which actually lead to the misinterpretation of the results in gene expression analysis.

Molecular Pathology of the Genitourinary Tract: Prostate and Bladder

The knowledge of cellular mechanisms in tumors of the prostate and bladder has grown exponentially. Molecular technologies have led to the discovery of TMPRSS2 in prostate cancer and the molecular pathways distinguishing low- and high-grade urothelial neoplasms. UroVysion with fluorescence in situ hybridization is already commonplace as an adjunct to cytologic diagnosis of urothelial neoplasms. This trend portends the future in which classification and diagnosis of tumors of the prostate and bladder through morphologic analysis will be supplemented by molecular information correlating with prognosis and targeted therapy. This article outlines tumor molecular pathology of the prostate and bladder encompassing current genomic, epigenomic, and proteonomic findings.

KLF6 and TP53 mutations are a rare event in prostate cancer: distinguishing between Taq polymerase artifacts and true mutations

Krüppel-like factor 6 (KLF6) has been reported to act as a tumor suppressor gene involved in the regulation of the cell cycle by activating p21 in a p53-independent manner. Many studies suggest that KLF6 is inactivated by allelic loss and somatic mutation. However, there is a high variability in the reported frequency of mutations (from 1 to 55%). TP53 also regulates the cell cycle through the activation of p21. In prostate cancer, the reported frequency of TP53 mutations ranges from 3 to 42%. In all these reports, there is a considerable degree of methodological heterogeneity. Our aim was to determine the frequency of KLF6 and TP53 mutations in a well-defined group of prostate tumors with different stages and Gleason grades. The four exons of KLF6 and exons 4-9 of TP53 were studied in 103 cases, including 90 formalin-fixed, paraffin-embedded (FFPE) and 13 frozen samples. All tumors were analyzed through PCR and direct sequencing. All changes found were confirmed by a second independent PCR and sequencing reaction. For KLF6, mutation (E227G) was only detected in one tumor (1%) and for TP53, three different mutations (L130H, H214R, and Y234C) were detected in five tumors (5%). This low mutation index is in keeping with recent papers on the subject. Our study strongly supports the notion that KLF6 and TP53 mutations are not frequent events in prostate cancer. When using FFPE tissues, it is mandatory to perform at least two independent rounds of PCR and sequencing to confirm mutations and exclude Taq polymerase-induced artifacts.

Overexpression of CD24, c-myc and phospholipase 2A in prostate cancer tissue samples obtained by needle biopsy

Altered CD24, c-myc and phospholipase 2a expression was reported in different cancers. Our aim was to measure the expression of these genes in prostate cancer tissues, and compare it to non-cancerous samples. Prostate tissue samples were collected by needle biopsy from 20 prostate cancer (PCA) and 11 benign prostate hyperplasic (BPH) patients. RNA was isolated; cDNA synthetized, CD24, c-myc and phospholipase 2A (PL2A) expressions were determined by quantitative real-time PCR method. The expression of beta-globin gene was measured for normalization of the gene expression results. Serum prostate specific antigen (PSA) levels were determined by microparticle enzyme immunoassay (MEIA) method. PSA levels were significantly different between the PCA and BPH groups, 252.37 +/- 308.33 ng/ml vs. 3.5 +/- 2.14 ng/ml (p = 0.001), respectively. CD24 expression was 988.86 +/- 3041 ng/microl in prostate tumor and 4.00 +/- 4.25 ng/microl in the BPH group (p = 0.035). The c-myc expression was 88.32 +/- 11.93 ng/microl in the prostate tumor and 17.08 +/- 21.75 ng/microl in the BPH group (p = 0.02), and the PL2A 31.36 +/- 67.02 ng/microl was in PCA and 5.56 +/- 14.08 ng/microl in BPH (p = 0.025). Gleason's scores showed correlation with c-myc (p = 0.019) and PSA (p = 0.033) levels. Overexpression of PL2A, CD24 and c-myc was observed in prostate cancer samples using quantitative real-time PCR method.

Prostate cancer

In developed countries, prostate cancer is the second most frequently diagnosed cancer, and the third most common cause of death from cancer in men. Apart from age and ethnic origin, a positive family history is probably the strongest known risk factor. Clinically, prostate cancer is diagnosed as local or advanced, and treatments range from surveillance to radical local treatment or androgen-deprivation treatment. Androgen deprivation reduces symptoms in about 70-80% of patients with advanced prostate cancer, but most tumours relapse within 2 years to an incurable androgen-independent state. The recorded incidence of prostate cancer has substantially increased in the past two decades, probably because of the introduction of screening with prostate-specific antigen, the use of improved biopsy techniques for diagnosis, and increased public awareness. Trends in mortality from the disease are less clearcut. Mortality changes are not of the same magnitude as the changes in incidence, and in some countries mortality has been stable or even decreased. The disparity between reported incidence and mortality rates leads to the probable conclusion that only a small proportion of diagnosed low-risk prostate cancers will progress to life-threatening disease during the lifetime of the patient.

Androgen-response elements in hormone-refractory prostate cancer: implications for treatment development

Many attempts have been made to derive genetic signatures for progressive prostate cancer for both prognostic and therapeutic purposes. These investigations have resulted in the discovery of many pathways, but the signatures exhibit heterogeneity and restricted reproducibility. A thorough and disciplined analysis of genes with androgen-response elements that are expressed in progressive, castration-resistant prostate cancer is an integral step towards the development of new therapeutic or diagnostic targets. We discuss the effects of bona-fide downstream targets of the androgen receptor on cellular proliferation, evasion of apoptosis, and angiogenesis, and consider the clinical potential of these targets.

De-regulation of common housekeeping genes in hepatocellular carcinoma

Background

Tumorigenesis is associated with changes in gene expression and involves many pathways. Dysregulated genes include "housekeeping" genes that are often used for normalization for quantitative real-time RT-PCR (qPCR), which may lead to unreliable results. This study assessed eight stages of hepatitis C virus (HCV) induced hepatocellular carcinoma (HCC) to search for appropriate genes for normalization.

Results

Gene expression profiles using microarrays revealed differential expression of most "housekeeping" genes during the course of HCV-HCC, including glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and beta-actin (ACTB), genes frequently used for normalization. QPCR reactions confirmed the regulation of these genes. Using them for normalization had strong effects on the extent of differential expressed genes, leading to misinterpretation of the results.

Conclusion

As shown here in the case of HCV-induced HCC, the most constantly expressed gene is the arginine/serine-rich splicing factor 4 (SFRS4). The utilization of at least two genes for normalization is robust and advantageous, because they can compensate for slight differences of their expression when not co-regulated. The combination of ribosomal protein large 41 (RPL41) and SFRS4 used for normalization led to very similar results as SFRS4 alone and is a very good choice for reference in this disease as shown on four differentially expressed genes.

Molecular markers for prostate cancer

Serum PSA testing has been used for over 20 years as an aid in the diagnosis and management of prostate cancer. Although highly sensitive, it suffers from a lack of specificity, showing elevated serum levels in a variety of other conditions including prostatitis, benign prostate hyperplasia, and non-cancerous neoplasia. During this period, numerous serum protein analytes have been investigated as alternative and/or supplemental tests for PSA, however in general these analytes have likewise suffered from a lack of specificity, often showing serum elevations in other clinical presentations. More recently, molecular assays targeting prostate disease at the DNA or RNA level have been investigated for potential diagnostic and prognostic utility. With the aid of modern genomics technologies, a variety of molecular biomarkers have been discovered that show potential for specific correlation with prostate cancer. Much of this discovery has been retrospective, using microdissected tissue from prostatectomy. The goal of current research is to apply genomic assays to noninvasive specimens such as blood and urine. Progress in this area is the subject of this review.