miRNAs as biomarkers in prostate cancer

Bioinformatics-Assisted Extraction of All PCa miRNAs and their Target Genes

INTRODUCTION

To retrieve, and classify PCa miRNAs and identify the functional relationship between miRNAs and their targets through literature collection with computational analysis.

BACKGROUND

MicroRNAs play a role in gene regulation, which can either repress or activate the gene. Hence, the functions of miRNAs are dependent on the target gene. This study will be the first of its kind to combine computational analysis with corpus PCa data. Effectively, our study reported the huge number of miRNAs associated with PCa along with functional information.

OBJECTIVE

The identification and classification of previously known full PCa miRNAs and their targets were made possible by mining the literature data. Systems Biology and curated data mining assisted in identifying optimum miRNAs and their target genes for PCa therapy.

METHODS

PubMed database was used to collect the PCa literature up to December 2021. Pubmed. mineR package was used to extract the microRNAs associated articles and manual curation was performed to classify the microRNAs based on the function in PCa. PPI was constructed using the STRING database. Pathway analysis was performed using PANTHER and ToppGene Suite Software. Functional analysis was performed using ShinyGO software. Cluster analysis was performed using MCODE 2.0, and Hub gene analysis was performed using cytoHubba. The genemiRNA network was reconstructed using Cytoscape.

RESULTS

Unique PCa miRNAs were retrieved and classified from mined PCa literature. Six hundred and five unique miRNAs from 250 articles were considered as oncomiRs to trigger PCa. One hundred and twenty unique miRNAs from 118 articles were considered Tumor Suppressor miRNAs to suppress the PCa. Twenty-four unique miRNAs from 22 articles were utilized as treatment miRNAs to treat PCa. miRNAs target genes and their significant pathways, functions and hub genes were identified.

CONCLUSION

miR-27a, miR-34b, miR-495, miR-23b, miR-100, miR-218, Let-7a family, miR-27a- 5p, miR-34c, miR-34a, miR-143/-145, miR-125b, miR-124 and miR-205 with their target genes AKT1, SRC, CTNNB1, HRAS, MYC and TP53 are significant PCa targets.

Prostate cancer bone metastases biology and clinical management (Review)

Prostate cancer (PCa) is one of the most prominent causes of cancer-related mortality in the male population. A highly impactful prognostic factor for patients diagnosed with PCa is the presence or absence of bone metastases. The formation of secondary tumours at the bone is the most commonly observed site for the establishment of PCa metastases and is associated with reduced survival of patients in addition to a cohort of life-debilitating symptoms, including mobility issues and chronic pain. Despite the prevalence of this disease presentation and the high medical relevance of bone metastases, the mechanisms underlying the formation of metastases to the bone and the understanding of what drives the osteotropism exhibited by prostate tumours remain to be fully elucidated. This lack of in-depth understanding manifests in limited effective treatment options for patients with advanced metastatic PCa and culminates in the low rate of survival observed for this sub-set of patients. The present review aims to summarise the most recent promising advances in the understanding of how and why prostate tumours metastasise to the bone, with the ultimate aim of highlighting novel treatment and prognostic targets, which may provide the opportunity to improve the diagnosis and treatment of patients with PCa with bone metastases.

The Potential of MicroRNAs as Non-Invasive Prostate Cancer Biomarkers: A Systematic Literature Review Based on a Machine Learning Approach

Simple Summary

Prostate cancer (PCa) is the most common cancer in men worldwide. Screening and diagnosis are based on prostate-specific antigen (PSA) blood testing and digital rectal examination. Nevertheless, these methods are not specific and have a high risk of mistaken results. This has led to overtreatment and unnecessary radical therapy; thus, better prognostic tools are urgently needed. In this view, microRNAs (miRs) appear as potential non-invasive biomarkers for PCa diagnosis, prognosis, and therapy. As the scientific literature available in this field is huge and very often controversial, we identified and discussed three topics that characterize the investigated research area by combining the big data from the literature together with a novel machine learning approach. By analyzing the papers clustered into these topics we have offered a deeper understanding of the current research, which helps to contribute to the advancement of this research field.

Abstract

Background: Prostate cancer (PCa) is the second leading cause of cancer-related deaths in men. Although the prostate-specific antigen (PSA) test is used in clinical practice for screening and/or early detection of PCa, it is not specific, thus resulting in high false-positive rates. MicroRNAs (miRs) provide an opportunity as biomarkers for diagnosis, prognosis, and recurrence of PCa. Because the size of the literature on it is increasing and often controversial, this study aims to consolidate the state-of-art of relevant published research. Methods: A Systematic Literature Review (SLR) approach was applied to analyze a set of 213 scientific publications through a text mining method that makes use of the Latent Dirichlet Allocation (LDA) algorithm. Results and Conclusions: The result of this activity, performed through the MySLR digital platform, allowed us to identify a set of three relevant topics characterizing the investigated research area. We analyzed and discussed all the papers clustered into them. We highlighted that several miRs are associated with PCa progression, and that their detection in patients’ urine seems to be the more reliable and promising non-invasive tool for PCa diagnosis. Finally, we proposed some future research directions to help future scientists advance the field further.

miRNAs as molecular biomarkers for prostate cancer

MicroRNAs (miRNAs) are short noncoding RNA able to regulate specific mRNA stability, thus influencing target gene expression. Disrupted levels of several miRNA have been associated with prostate cancer, the leading cause of cancer death among men and the fifth leading cause of death worldwide. Here, we investigated whether miR-145, miR-148, and miR-185 circulating levels in plasma could be used as molecular biomarkers, to allow distinguishing between individuals with benign prostatic hyperplasia, precancerous lesion, and prostate cancer. In this study, we recruited 170 urological clinic patients with suspected prostate cancer who underwent prostate biopsy. Total RNA was isolated from plasma, and TaqMan MicroRNA assays were used to analyze miR-145, miR-185, and miR-148 expression. First, differential miRNA expression among patient groups was evaluated. Then, miRNA levels were combined with clinical assessment outcomes, including results from invasive tests, using multivariate analysis to examine their ability in discriminating among the three patient groups. Our results suggest that miRNA is a promising molecular tool for clinical management of at-risk patients.

The circSPON2/miR-331-3p axis regulates PRMT5, an epigenetic regulator of CAMK2N1 transcription and prostate cancer progression

BACKGROUND

Prostate cancer (PCa) is the most frequently diagnosed malignancy in men, and its mechanism remains poorly understood. Therefore, it is urgent to discover potential novel diagnostic biomarkers and therapeutic targets that can potentially facilitate the development of efficient anticancer strategies.

METHODS

A series of functional in vitro and in vivo experiments were conducted to evaluate the biological behaviors of PCa cells. RNA pulldown, Western blot, luciferase reporter, immunohistochemistry and chromatin immunoprecipitation assays were applied to dissect the detailed underlying mechanisms. High-throughput sequencing was performed to screen for differentially expressed circRNAs in PCa and adjacent normal tissues.

RESULTS

Upregulation of protein arginine methyltransferase 5 (PRMT5) is associated with poor progression-free survival and the activation of multiple signaling pathways in PCa. PRMT5 inhibits the transcription of CAMK2N1 by depositing the repressive histone marks H4R3me2s and H3R8me2s on the proximal promoter region of CAMK2N1, and results in malignant progression of PCa both in vitro and in vivo. Moreover, the expression of circSPON2, a candidate circRNA in PCa tissues identified by RNA-seq, was found to be associated with poor clinical outcomes in PCa patients. Further results showed that circSPON2 induced PCa cell proliferation and migration, and that the circSPON2-induced effects were counteracted by miR-331-3p. Particularly, circSPON2 acted as a competitive endogenous RNA (ceRNA) of miR-331-3p to attenuate the repressive effects of miR-331-3p on its downstream target PRMT5.

CONCLUSIONS

Our findings showed that the epigenetic regulator PRMT5 aggravates PCa progression by inhibiting the transcription of CAMK2N1 and is modulated by the circSPON2/miR-331-3p axis, which may serve as a potential therapeutic target for patients with aggressive PCa.

Role of miRNA-182 and miRNA-187 as potential biomarkers in prostate cancer and its correlation with the staging of prostate cancer

Purpose

The microRNAs expression has emerged as a potential biomarker for the diagnosis and prognosis of prostate cancer. This study investigated the expression of miRNA-182 and miRNA-187 in prostate cancer patients and established a correlation between miRNA expression and staging of prostate cancer.

Materials and Methods

This prospective observational study involved patients undergoing transrectal ultrasound-guided biopsy for suspicion of prostate cancer. Pre-biopsy urine samples and prostatic core tissue samples of the patients were preserved and the miRNA-182 and miRNA-187 were studied.

Results

Sixty-three patients were included in this study, thirty-three patients were diagnosed with prostate cancer and thirty patients having benign histopathology were considered as controls. The expression of miRNA-182 was significantly increased (p=0.002) and miRNA-187 significantly decreased (p <0.001) in prostate cancer tissue specimens. However, the expression of these miRNAs did not significantly differ in the urine of prostate cancer patients as compared to controls. Serum Prostatic Specific Antigen (PSA) inversely correlated with the median expression of miR-187 in prostatic tissue (p=0.002). Further, the expression of miRNA-187 in prostate cancer tissue was significantly decreased in metastatic prostate cancer (p=0.037). Using ROC analysis, miRNA-187 expression was able to distinguish the presence or absence of bone metastasis [area under ROC (AUROC) (±SD) was 0.873±0.061, p <0.001].

Conclusion

The miRNA-182 and miRNA-187 appear to be promising biomarkers in prostate cancer and miRNA-187 can serve as an important diagnostic marker of metastatic prostate cancer.

The association of let-7c, miR-21, miR-145, miR-182, and miR-221 with clinicopathologic parameters of prostate cancer in patients diagnosed with low-risk disease

BACKGROUND

The diagnostic benefit of prostate specific antigen (PSA) is limited, owing to its lack of specificity, particularly in men with PSA levels of 4.0 to 10.0 ng/mL. Therefore, there is a need for more specific and sensitive biomarkers to improve diagnostic accuracy and to predict prostate cancer (PCa) progression. Assessing the expression levels of specific microRNAs (miRNAs) in patients with PCa may be helpful in detecting cancer and predicting the cancer prognosis and its evolution, and may serve as markers to decide the treatment. We examined the expression levels of five miRNAs (let-7c, miR-21, miR-145, miR-185, and miR-221) on patients with low-risk PCa who had been eligible for active surveillance but underwent radical prostatectomy. We investigated the correlation between the relative expression of miRNAs and clinicopathologic parameters to evaluate their clinical significance.

MATERIALS AND METHODS

Total RNA was isolated from the tumor and the corresponding non-neoplastic prostate tissue of 45 patients who underwent radical prostatectomy. Quantitative reverse transcriptase-polymerase chain reaction was used to measure the levels of let-7c, miR-21, miR-145, miR-185, miR-221, and RNU6B expression, using TaqMan MicroRNA Assays. miRNA expression was examined in low-risk PCa, and miRNAs' association with Gleason upgraded (GU) and biochemical recurrent (BR) patients was evaluated.

RESULTS

We observed that miR-21 and miR-182 were overexpressed; conversely, let-7c, miR-145, and miR-221 were underexpressed in patients with low-risk PCa. GU patients (n = 16) and non-upgraded patients (n = 28) were compared. miR-145 was downregulated significantly in the GU group (P = 0.03). Similarly, miR-221 was downregulated significantly in patients with BR (n = 14) compared with non-recurrent patients (n = 30) (P = 0.04). Receiver operator characteristics (ROC) curve analysis revealed that miR-221 levels were significantly associated with BR in patients with a cut-off <-1.666, a value at which sensitivity was 70% and specificity 71% (area under curve [AUC] = 0.705, P = 0.030).

CONCLUSIONS

There is still a need for a tumor marker with higher sensitivity and specificity than that of PSA. Among the five miRNAs examined, miR-221 was most associated with biochemical recurrence in low-risk PCa.

Experimental study of the evanescent-wave photonic sensors response in presence of molecular beacon conformational changes

An experimental study of the influence of the conformational change suffered by molecular beacon (MB) probes-upon the biorecognition of nucleic acid target oligonucleotides over evanescent wave photonic sensors-is reported. To this end, high sensitivity photonic sensors based on silicon photonic bandgap (PBG) structures were used, where the MB probes were immobilized via their 5' termination. Those MBs incorporate a biotin moiety close to their 3' termination in order to selectively bind a streptavidin molecule to them. The different photonic sensing responses obtained toward the target oligonucleotide detection, when the streptavidin molecule was bound to the MB probes or not, demonstrate the conformational change suffered by the MB upon hybridization, which promotes the displacement of the streptavidin molecule away from the surface of the photonic sensing structure.

miRNA-205 Nanoformulation Sensitizes Prostate Cancer Cells to Chemotherapy

The therapeutic application of microRNA(s) in the field of cancer has generated significant attention in research. Previous studies have shown that miR-205 negatively regulates prostate cancer cell proliferation, metastasis, and drug resistance. However, the delivery of miR-205 is an unmet clinical need. Thus, the development of a viable nanoparticle platform to deliver miR-205 is highly sought. A novel magnetic nanoparticle (MNP)-based nanoplatform composed of an iron oxide core with poly(ethyleneimine)-poly(ethylene glycol) layer(s) was developed. An optimized nanoplatform composition was confirmed by examining the binding profiles of MNPs with miR-205 using agarose gel and fluorescence methods. The novel formulation was applied to prostate cancer cells for evaluating cellular uptake, miR-205 delivery, and anticancer, antimetastasis, and chemosensitization potentials against docetaxel treatment. The improved uptake and efficacy of formulations were studied with confocal imaging, flow cytometry, proliferation, clonogenicity, Western blot, q-RT-PCR, and chemosensitization assays. Our findings demonstrated that the miR-205 nanoplatform induces significant apoptosis and enhancing chemotherapeutic effects in prostate cancer cells. Overall, these study results provide a strong proof-of-concept for a novel nonviral-based nanoparticle protocol for effective microRNA delivery to prostate cancer cells.

miR-1266-5p and miR-185-5p Promote Cell Apoptosis in Human Prostate Cancer Cell Lines

Objective:

Small non-coding RNA molecules are dysregulated in prostate cancer (PCa). In our previous study, downregulation of miR-1266 and miR-185 was demonstrated in PCa tissues and cell lines. The aim of the present study was to investigate whether miR-1266 and miR-185 are involved in the regulation of B-cell lymphoma (BCL) 2 and BCL2L1, respectively, and whether transfection of PCa cell lines with miR-1266 and miR-185 mimics can alter tumorigenic phenotypes.

Methods:

In order to investigate the regulation of BCL2 and BCL2L1 mRNA levels by miR-1266 and miR-185, respectively, a luciferase reporter assay was used. Real-time PCR was also used to analyze changes in the levels of BCL2 and BCL2L1 mRNAs in PCa cell lines following transfection with synthetic miR-1266 and miR-185. Cell apoptosis was determined by Annexin V protein expression analysis via flow cytometry. In addition to the MTT assay, a cell proliferation assay was performed.

Result:

A luciferase assay confirmed that the BCL2 and BCL2L1 genes may be targeted by miR-1266 and miR-185, respectively, through binding to their 3′UTR regions. Transfection of PC3 and DU145 cells with miR-1266 and miR-185 induced apoptosis and reduced proliferation, which also revealed an inverse correlation with BCL2 and BCL2L1 gene expression in the treated cells.

Conclusion:

Our data suggests that miR-1266 and miR-185 may be novel candidates for further research in PCa treatment through the anti-apoptotic pathway.

High sensitivity and label-free oligonucleotides detection using photonic bandgap sensing structures biofunctionalized with molecular beacon probes

A label-free sensor, based on the combination of silicon photonic bandgap (PBG) structures with immobilized molecular beacon (MB) probes, is experimentally developed. Complementary target oligonucleotides are specifically recognized through hybridization with the MB probes on the surface of the sensing structure. This combination of PBG sensing structures and MB probes demonstrates an extremely high sensitivity without the need for complex PCR-based amplification or labelling methods.

miR-885-5p suppresses hepatocellular carcinoma metastasis and inhibits Wnt/β-catenin signaling pathway

MicroRNAs (miRNAs) inhibit or improve the malignant progression of hepatocellular carcinoma (HCC). We previously reported that compared to health controls, patients with liver cirrhosis present the highest levels of circulating miR-885-5p, followed by those with chronic hepatitis B and those with HCC. However, the molecular involvement of miR-885-5p in HCC metastasis is presently unclear. Here, we demonstrated that the expression of miR-885-5p negatively correlated with the invasive and metastatic capabilities of human HCC tissue samples and cell lines. We found that miR-885-5p expression levels correlated with the survival of patients with HCC. Overexpression of miR-885-5p decreased metastasis of HCC cells in vitro and in vivo. Inhibition of miR-885-5p improved proliferation of non-metastatic HCC cells. Furthermore, we disclosed that miR-885-5p targeted gene encoding β-catenin CTNNB1, leading to decreased activity of the Wnt/β-catenin signaling pathway. The present study indicates that miR-885-5p suppresses the metastasis of HCC and inhibits Wnt/β-catenin signaling pathway by its CTNNB1 target, which suggests that miR-885-5p to be a promising negative regulator of HCC progression and as a novel therapeutic agent to treat HCC.

Identification of tumor suppressive role of microRNA-132 and its target gene in tumorigenesis of prostate cancer

Previous literature exists on the role of microRNA (miR)-132 in initiation and progression of various malignancies. In this study, we aimed at understanding the relationship of miR-132 of prostate tumorigenesis. We collected 32 prostate cancer tissues and adjacent non-cancerous controls, and detected the expression level of miR-132. Then the miRNA database was searched online and luciferase assay perform to understand the regulatory relationship between miR-132 and E2F5. Moreover, we also conducted real-time PCR and western blot analysis to study the mRNA and protein expression level of E2F5 among different groups (cancerous tissue, n=32; non-cancerous tissue, n=32) or cells treated with scramble control, miR-132 mimics, E2F5 siRNA and miR-132 inhibitors. miR-132 was upregulated in cancerous tissues of prostate cancer patients. E2F5 was the target of miR-132, and negative regulatory relationship between miR-132 and E2F5 was also confirmed by luciferase assay. The mRNA and protein expression level of E2F5 increased in cancerous tissue group. miR-132 decreased the expression of E2F5 in prostate cancer cells, and introduction of miR-132 reduced the viability and E2F5 and promoted the viability of prostate cancer cells. miR-132 inhibited apoptosis and E2F5 accelerated apoptosis. In conclusion, miR-132 was upregulated in cancerous tissue of prostate cancer. E2F5 was a direct target of miR-132, and downregulation of E2F5 caused by upregulation of miR-132 may contribute to the tumorigenesis of prostate cancer.

Inhibition of microRNA-500 has anti-cancer effect through its conditional downstream target of TFPI in human prostate cancer

PURPOSE

We investigated the prognostic potential and regulatory mechanism of microRNA-500 (miR-500), and human gene of tissue factor pathway inhibitor (TFPI) in prostate cancer.

METHODS

MiR-500 expression was assessed by qRT-PCR in prostate cancer cell lines and primary tumors. Cancer patients' clinicopathological factors and overall survival were analyzed according to endogenous miR-500 level. MiR-500 was downregulated in DU145 and VCaP cells. Its effect on prostate cancer proliferation, invasion in vitro, and tumorigenicity in vivo, were probed. Possible downstream target of miR-500, TFPI was assessed by luciferase assay and qRT-PCR in prostate cancer cells. In miR-500-downregulated DU145 and VCaP cells, TFPI was silenced to see whether it was directly involved in the regulation of miR-500 in prostate cancer. TFPI alone was either upregulated or downregulated in DU145 and VCaP cells. Their effect on prostate cancer development was further evaluated.

RESULTS

MiR-500 is upregulated in both prostate cancer cells and primary tumors. In prostate cancer patients, high miR-500 expression is associated with poor prognosis and overall survival. In DU145 and VCaP cells, miR-500 downregulation inhibited cancer proliferation, invasion in vitro, and explant growth in vivo. TFPI was verified to be associated with miR-500 in prostate cancer. Downregulation of TFPI reversed anti-cancer effects of miR-500 downregulation in prostate cancer cells. However, neither TFPI upregulation nor downregulation alone had any functional impact on prostate cancer development.

CONCLUSION

MiR-500 may be a potential biomarker and molecular target in prostate cancer. TFPI may conditionally regulate prostate cancer in miR-500-downregualted prostate cancer cells.

Significantly altered expression of miR-511-3p and its target AKT3 has negative prognostic value in human prostate cancer

PURPOSE

In this study, we assessed the expression and functions of microRNA-511-3p (miR-511-3p) in human prostate cancer (CaP).

METHODS

Gene expressions of miR-511-3p in CaP cells and human CaP tumors were assessed by qPCR. In VCaP and PC3 cells, miR-511-3p was overexpressed by lentivirus. The functions of miR-511-3p upregulation in regulating in vitro cancer proliferation, migration and in vivo cancer growth were assessed by MTT, transwell and transplantation assays, respectively. Downstream target gene of miR-511-3p, AKT3, was verified by dual-luciferase activity and qPCR assays. AKT3 was then overexpressed in miR-511-3p-upregulated CaP cells to assess its functions in miR-511-3p-mediated cancer regulation.

RESULTS

MiR-511-3p is significantly downregulated in CaP cell lines, and human CaP tumors. MiR-511-3p was further downregulated in T3/T4-staged CaP tumors and closely correlated with shorter overall survival among CaP patients. In VCaP and PC3 cells, lentiviral-induced miR-511-3p upregulation was acting as a tumor suppressor by inhibiting in vitro cancer proliferation, migration and in vivo transplantation. Human AKT3 gene was confirmed to be the downstream target of miR-511-3p in CaP. In miR-511-3p-upregulated VCaP and PC3 cells, forced-overexpression of AKT3 reversed the tumor suppressive effects of miR-511-3p in CaP.

CONCLUSION

MiR-511-3p may serve as a prognostic factor and tumor suppressor in CaP, very likely through inverse regulation of its downstream target gene of AKT3.

PCA3 as a second-line biomarker in a prospective controlled randomized opportunistic prostate cancer screening programme

OBJECTIVES

PCA3 performance as a single second line biomarker is compared to the European Randomised Study of Screening for Prostate Cancer risk calculator model 3 (ERSPC RC-3) in an opportunistic screening in prostate cancer (PCa).

MATERIAL AND METHODS

5,199 men, aged 40-75y, underwent prostate-specific antigen (PSA) screening and digital rectal examination (DRE). Men with a normal DRE and PSA ≥3ng/ml had a PCA3 test done. All men with PCA3 ≥35 underwent an initial biopsy (IBx) -12 cores-. Men with PCA3 <35 were randomized 1:1 to either IBx or observation. We compared them to those obtained with ERSPC RC-3.

RESULTS

PCA3 test was performed on 838 men (16.1%). In PCA3(+) and PCA3(-) groups, global PCa detection rates were 40.9% and 14.7% with a median follow-up (FU) of 21.7 months (P<.001). In the PCA3(+) arm (n=301, 35.9%), PCa was identified in 115 men at IBx (38.2%). In the randomized arm, 256 underwent IBx and PCa was found in 46 (18.0%) (P<.001). The biopsy-sparing potential would have been 64.1% as opposed to 76.6% if we had used ERSPC RC-3. However, the estimated false negative cases for HGPCa would have been reduced by 37.1% (89 to 56 patients). Moreover, if we had applied PCA3-35 to avoid IBx, 14.7% PCa and 9.1% of clinical significant PCa patients would not have been diagnosed during this FU.

CONCLUSIONS

When PCA3-35 is used as a second-line biomarker when PSA ≥3ng/ml and DRE is normal, IBx could be avoided in 12.5% less than if ERSPC RC-3 is used and would reduce the false negative cases by 36.2%. At a FU of 21.7 months, this dual protocol would miss 9.1% of clinically significant PCa, so strict FU is mandatory with established biopsy criteria based on PSA and DRE in cases with PCA3 <35.

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.

miRNAs as drivers of TMPRSS2-ERG negative prostate tumors in African American men

African Americans (AAs) who have PCa typically have more aggressive disease and make up a disproportionate number of the disease deaths, relative to European Americans (EAs). TMPRSS2 translocations, a common event in EA patients, are exploited in diagnostic and prognostic settings, whereas they are diminished in frequency in AA men. Thus, these patients with TMPRSS2 fusion-negative disease represent an under-investigated patient group. We propose that epigenetic events are a significant and alternative driver of aggressive disease in fusion-negative PCa. To reveal epigenetically governed microRNAs (miRNAs) that are enriched in fusion-negative disease and associated with aggressive in AA PCa, we leveraged both our experimental evidence and publically available data. These analyses identified 18 miRNAs that are differentially altered in fusion-negative disease, associated with DNA CpG methylation, and implicated in aggressive and AA PCas. Understanding the relationships between miRNA expression, upstream epigenetic regulation by DNA methylation, and downstream regulation of mRNA targets in fusion negative disease is imperative to understanding the biological basis of the racial health disparity in PCa.

MiR-573 inhibits prostate cancer metastasis by regulating epithelial-mesenchymal transition

The metastastic cascade is a complex process that is regulated at multiple levels in prostate cancer (PCa). Recent evidence suggests that microRNAs (miRNAs) are involved in PCa metastasis and hold great promise as therapeutic targets. In this study, we found that miR-573 expression is significantly lower in metastatic tissues than matched primary PCa. Its downregulation is correlated with high Gleason score and cancer-related mortality of PCa patients (P = 0.041, Kaplan-Meier analysis). Through gain- and loss-of function experiments, we demonstrated that miR-573 inhibits PCa cell migration, invasion and TGF-β1-induced epithelial-mesenchymal transition (EMT) in vitro and lung metastasis in vivo. Mechanistically, miR573 directly targets the fibroblast growth factor receptor 1 (FGFR1) gene. Knockdown of FGFR1 phenocopies the effects of miR-573 expression on PCa cell invasion, whereas overexpression of FGFR1 partially attenuates the functions of miR-573. Consequently, miR-573 modulates the activation of FGFR1-downstream signaling in response to fibroblast growth factor 2 (FGF2). Importantly, we showed that GATA3 directly increases miR-573 expression, and thus down-regulates FGFR1 expression, EMT and invasion of PCa cells in a miR-573-dependent manner, supporting the involvement of GATA3, miR-573 and FGFR1 in controlling the EMT process during PCa metastasis. Altogether, our findings demonstrate a novel mechanism by which miR-573 modulates EMT and metastasis of PCa cells, and suggest miR-573 as a potential biomarker and/or therapeutic target for PCa management.

Biomarkers in localized prostate cancer

Biomarkers can improve prostate cancer diagnosis and treatment. Accuracy of prostate-specific antigen (PSA) for early diagnosis of prostate cancer is not satisfactory, as it is an organ- but not cancer-specific biomarker, and it can be improved by using models that incorporate PSA along with other test results, such as prostate cancer antigen 3, the molecular forms of PSA (proPSA, benign PSA and intact PSA), as well as kallikreins. Recent reports suggest that new tools may be provided by metabolomic studies as shown by preliminary data on sarcosine. Additional molecular biomarkers have been identified by the use of genomics, proteomics and metabolomics. We review the most relevant biomarkers for early diagnosis and management of localized prostate cancer.

MicroRNA-125a-5p regulates cancer cell proliferation and migration through NAIF1 in prostate carcinoma

Background

We investigated the functional roles of microRNA-125a-5p in regulating human prostate carcinoma.

Methods

Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was conducted to evaluate the gene expression levels of miR-125a-5p in eight prostate cancer cell lines and nine biopsy specimens from patients with prostate cancer. miR-125a-5p was genetically knocked down in prostate cancer cell lines, DU145 and VCaP cells by lentiviral transduction. The effects of miR-125a-5p downregulation on prostate cancer cell proliferation and migration were evaluated by MTT assay and transwell assay, respectively. Direct regulation of miR-125a-5p on its downstream targets, NAIF1, and apoptotic gene caspase-3 were evaluated through dual-luciferase reporter assay, qRT-PCR, and Western blot, respectively. NAIF1 was then ectopically overexpressed in DU145 and VCaP cells to modulate prostate cancer cell proliferation and migration. Finally, the effects of miR-125a-5p downregulation or NAIF1 overexpression on the growth of in vivo prostate cancer xenograft were evaluated.

Results

miR-125a-5p was upregulated in prostate cancer cell lines and human prostate carcinomas. Lentivirus induced miR-125a-5p downregulation in DU145 and VCaP cells inhibited prostate cancer cell proliferation or migration. NAIF1 was the direct target of miR-125a-5p, as both gene and protein expression levels of NAIF1, as well as caspase-3 were upregulated by miR-125a-5p. Forced overexpression of NAIF1 had similar antitumor effects as miR-125a-5p downregulation on prostate cancer cell proliferation and migration. In vivo prostate xenograft assay confirmed the tumor-suppressive effect of miR-125a-5p downregulation or NAIF1 overexpression.

Conclusion

miR-125a-5p regulates prostate cancer cell proliferation and migration through NAIF1.

Diagnostic and prognostic values of tissue hsa-miR-30c and hsa-miR-203 in prostate carcinoma

Prostate cancer (PCa) has become a prevalent malignant disease in males globally. Accumulating data suggested that hsa-microRNAs (miRNAs) could be potential biomarkers for tumor diagnosis due to their important roles in the cell cycle. This study investigated the diagnostic and prognostic values of hsa-miR-203 and hsa-miR-30c in PCa tissues. There were 44 pathologically confirmed PCa patients who were enrolled in this study. Tissue samples were collected from both tumor tissues and adjacent normal tissues. RNA was extracted and the expression levels of hsa-miR-203 and hsa-miR-30c in tumor and normal tissues were compared. The receiver operating characteristic (ROC) curves were plotted to evaluate the reliability of hsa-miR-203 and hsa-miR-30c in detecting PCa. All subjects in this study were followed up by 36 months, and the Kaplan-Meier method was conducted to investigate the survival status of PCa patients. The average relative expressions of hsa-miR-203 and hsa-miR-30c in tumor tissues were significantly different from those in adjacent normal tissues (P < 0.001), and the predictive power of the two hsa-miRNAs for PCa prognosis was reliable. Besides that, the average survival times of low-hsa-miR-30c and high-hsa-miR-203 groups were significantly lower than those of the corresponding groups with the log-rank P of 0.015 and 0.023, respectively. In summary, our study suggested that both hsa-miR-203 and hsa-miR-30c are potential biomarkers for detection and prognosis of PCa.

MiR-187 Targets the Androgen-Regulated Gene ALDH1A3 in Prostate Cancer

miRNAs are predicted to control the activity of approximately 60% of all protein-coding genes participating in the regulation of several cellular processes and diseases, including cancer. Recently, we have demonstrated that miR-187 is significantly downregulated in prostate cancer (PCa) and here we propose a proteomic approach to identify its potential targets. For this purpose, PC-3 cells were transiently transfected with miR-187 precursor and miRNA mimic negative control. Proteins were analyzed by a two-dimensional difference gel electrophoresis (2D-DIGE) and defined as differentially regulated if the observed fold change was ±1.06. Then, MALDI-TOF MS analysis was performed after protein digestion and low abundance proteins were identified by LC-MS/MS. Peptides were identified by searching against the Expasy SWISS PROT database, and target validation was performed both in vitro by western blot and qRT-PCR and in clinical samples by qRT-PCR, immunohistochemistry and ELISA. DIGE analysis showed 9 differentially expressed spots (p<0.05) and 7 showed a down-regulated expression upon miR-187 re-introduction. Among these targets we identified aldehyde dehydrogenase 1A3 (ALDH1A3). ALDH1A3 expression was significantly downregulated in PC3, LNCaP and DU-145 cells after miR-187 re-introduction. Supporting these data, the expression of ALDH1A3 was found significantly (p<0.0001) up-regulated in PCa samples and inversely correlated (p<0.0001) with miR-187 expression, its expression being directly associated with Gleason score (p = 0.05). The expression of ALDH1A3 was measured in urine samples to evaluate the predictive capability of this biomarker for the presence of PCa and, at a signification level of 10%, PSA and also ALDH1A3 were significantly associated with a positive biopsy of PCa. In conclusion, our data illustrate for the first time the role of ALDH1A3 as a miR-187 target in PCa and provide insights in the utility of using this protein as a new biomarker for PCa.

MicroRNA as new tools for prostate cancer risk assessment and therapeutic intervention: results from clinical data set and patients' samples

Prostate cancer (PCa) is one of the leading causes of cancer-related death in men. Despite considerable advances in prostate cancer early detection and clinical management, validation of new biomarkers able to predict the natural history of tumor progression is still necessary in order to reduce overtreatment and to guide therapeutic decisions. MicroRNAs are endogenous noncoding RNAs which offer a fast fine-tuning and energy-saving mechanism for posttranscriptional control of protein expression. Growing evidence indicate that these RNAs are able to regulate basic cell functions and their aberrant expression has been significantly correlated with cancer development. Therefore, detection of microRNAs in tumor tissues and body fluids represents a new tool for early diagnosis and patient prognosis prediction. In this review, we summarize current knowledge about microRNA deregulation in prostate cancer mainly focusing on the different clinical aspects of the disease. We also highlight the potential roles of microRNAs in PCa management, while also discussing several current challenges and needed future research.

Nucleic acid-based biomarkers in body fluids of patients with urologic malignancies

This review focuses on the promising potential of nucleic acids in body fluids such as blood and urine as diagnostic, prognostic, predictive and monitoring biomarkers in urologic malignancies. The tremendous progress in the basic knowledge of molecular processes in cancer, as shown in the companion review on nucleic acid-based biomarkers in tissue of urologic tumors, provides a strong rationale for using these molecular changes as non-invasive markers in body fluids. The changes observed in body fluids are an integrative result, reflecting both tissue changes and processes occurring in the body fluids. The availability of sensitive methods has only recently made possible detailed studies of DNA- and RNA-based markers in body fluids. In addition to these biological aspects, methodological aspects of the determination of nucleic acids in body fluids, i.e. pre-analytical, analytical and post-analytical issues, are particularly emphasized. The characteristic changes of RNA (differential mRNA and miRNA expression) and DNA (concentrations, integrity index, mutations, microsatellite and methylation alterations) in serum/plasma and urine samples of patients suffering from the essential urologic cancers of the prostate, bladder, kidney and testis are summarized and critically discussed below. To translate the promising results into clinical practice, laboratory scientists and clinicians have to collaborate to resolve the challenges of harmonized and feasible pre-analytical and analytical conditions for the selected markers and to validate these markers in well-designed and sufficiently powered multi-center studies.

The role of miRNAs in cancer: from pathogenesis to therapeutic implications

ABSTRACT: 

Cancer is still one of the dominating causes of deaths worldwide, although there have been important enhancements for detection and diagnosis of cancer recently. miRNAs are shown to participate in carcinogenesis of several types of tumors and their aberrant expression of miRNAs has been detected in cell lines, xenografts and clinical samples. miRNAs are thought to target and modulate the expression of more than 60% of human genes, which makes the expressional regulation by miRNAs the most abundant post-transcriptional regulation mode. Here, we have reviewed the most current literature to shed a light on the functions of miRNAs on human carcinogenesis. Possible roles of miRNAs in oncogenesis through both genetic and epigenetic changes occurring during cancer initiation, progression, invasion or metastasis are summarized.

Optimizing prostate cancer screening; prospective randomized controlled study of the role of PSA and PCA3 testing in a sequential manner in an opportunistic screening program

OBJECTIVES

To reduce unnecessary biopsies (Bx) in an opportunistic screening programme of prostate cancer.

MATERIAL AND METHODS

We perform a prospective evaluation of PCA3 as a second line biomarker in an opportunistic screening for prostate cancer (PCa). From September-2010 until September-2012, 2,366 men, aged 40-74 years and with >10 years life expectancy, were initially screened with PSA/digital rectal examination (DRE). Men with previous Bx or with recent urine infections were excluded. Men with abnormal DRE and/or PSA >3 ng/ml were submitted for PCA3. All men with PCA3 ≥ 35 underwent an initial biopsy (IBx) -12cores-. Men with PCA3 < 35 were randomized 1:1 to either IBx or observation. Re-biopsy(16-18 cores) criteria were PSA increase >.5 ng/ml at 4-6 months or PSAv > .75 ng/ml/year.

RESULTS

With median follow-up (FU) of 10.1 months, PCA3 was performed in 321/2366 men (13.57%), 289 at first visit and 32 during FU. All 110 PCA3+ men (34.3%) were biopsied and PCa was identified in 43 men in IBx (39.1%). In the randomized arm, 110 were observed and 101 underwent biopsy, finding 12 PCa (11.9%), showing a statistically significant reduction of PCa detection rate in this cohort (P<.001). Global PCa detection rates were 40.9% and 9.5% for the PCA3+ and PCA3- branches, respectively (P<.001). Area under the curve for PSA and PCA3 were .601 and .74, respectively. This is an ongoing prospective study limited by its short follow-up period and still limited enrolment.

CONCLUSIONS

PCA3 as a second line biomarker within an opportunistic dual screening protocol, can potentially avoid 65.7% and 50.1% biopsies at first round and at median FU of 10.1 months, respectively, just missing around 3.2% of high grade PCa.

Global analysis of the differentially expressed miRNAs of prostate cancer in Chinese patients

Background

Our recent study showed the global physiological function of the differentially expressed genes of prostate cancer in Chinese patients was different from that of other non-Chinese populations. microRNA are estimated to regulate the expression of greater than 60% of all protein-coding genes. To further investigate the global association between the transcript abundance of miRNAs and their target mRNAs in Chinese patients, we used microRNA microarray approach combined with bioinformatics and clinical-pathological assay to investigate the miRNA profile and evaluate the potential of miRNAs as diagnostic and prognostic markers in Chinese patients.

Results

A total of 28 miRNAs (fold change ≥1.5; P ≤ 0.05) were differentially expressed between tumor tissue and adjacent benign tissue of 4 prostate cancer patients.10 top Differentially expressed miRNAs were validated by qRT-PCR using all 20 tissue pairs. Compared to the miRNA profile of non-Chinese populations, the current study showed that miR-23b, miR-220, miR-221, miR-222, and miR-205 maybe common critical therapeutic targets in different populations. The integrated analysis for mRNA microarray and miRNA microarray showed the effects of specifically inhibiting and/or enhancing the function of miRNAs on the gene transcription level. The current studies also identified 15 specific expressed miRNAs in Chinese patients. The clinical feature statistics revealed that miR-374b and miR-19a have significant correlations with clinical-pathological features in Chinese patients.

Conclusions

Our findings showed Chinese prostate cancer patients have a common and specific miRNA expression profile compared with non-Chinese populations. The miR-374b is down-regulated in prostate cancer tissue, and it can be identified as an independent predictor of biochemical recurrence-free survival.

Personalized management in low-risk prostate cancer: the role of biomarkers

Current criteria to predict low-risk prostate cancer (PCa) are still subject to discussion as a substantial number of PCa patients who progress to a more aggressive disease seem to be missed, using these criteria. The main challenge in PCa diagnosis, therefore, is to distinguish patients with low-risk PCa who will show slow progression of disease from patients at risk for progression to a more aggressive cancer. The current discovered biomarkers could potentially guide in this management and improve detection, staging, and prognosis. This paper provides an overview of the current available serum-, urine-, and tissue-based biomarkers in PCa and evaluates the clinical usefulness of these biomarkers in the detection and management of low-risk PCa.