Candidate diagnostic miRNAs that can detect cancer in prostate biopsy

LncRNA VPS9D1-AS1 regulates miR-187-3p/fibroblast growth factor receptor-like 1 axis to promote proliferation, migration, and invasion of prostate cancer cells

The morbidity and mortality of prostate cancer are increasing year by year, and the survival rate of prostate cancer patients after treatment is low. Therefore, investigating the molecular mechanism underlying prostate cancer is crucial for developing effective treatments. Recent studies have shown the important role of long-chain non-coding RNAs (lncRNAs) in tumorigenesis. VPS9D1-AS1 can modulate the progression of multiple cancers, but its molecular action mechanism in prostate cancer remains unknown. This study, therefore, intended to investigate the regulatory mechanism of VPS9D1-AS1 in prostate cancer. First, differentially expressed lncRNAs in prostate cancer were identified through bioinformatics approaches. The target lncRNA for the study was determined by reviewing the relevant literature and its downstream miRNA/mRNA axis was uncovered. Then, quantitative reverse transcription polymerase chain reaction was introduced to assess the expression of VPS9D1-AS1, miR-187-3p, and fibroblast growth factor receptor-like 1 (FGFRL1) at a cellular level, and Western blot was conducted to assess the protein level of FGFRL1 in cells. The results indicated that VPS9D1-AS1 and FGFRL1 were highly expressed in prostate cancer while miR-187-3p was less expressed. Besides, MTT, colony formation, wound healing, and cell invasion assays showed that silencing VPS9D1-AS1 inhibited the viability, migration ability, and invasion ability of prostate cancer cells. Dual-luciferase assay and RNA binding protein immunoprecipitation assay were performed to explore the interplay of miR-187-3p and VPS9D1-AS1 or FGFRL1. The results showed that VPS9D1-AS1 could sponge miR-187-3p, and FGFRL1 could serve as a direct target of miR-187-3p. Moreover, combined with the results of the rescue experiment, VPS9D1-AS1 was found to upregulate FGFRL1 by competitively sponging miR-187-3p to accelerate the malignant behaviors of prostate cancer cells. In conclusion, VPS9D1-AS1 could promote the phenotype progression of prostate cancer cells through targeting the miR-187-3p/FGFRL1 axis, and it has the potential to be a target for prostate cancer patients.

MiR-183-5p promotes migration and invasion of prostate cancer by targeting TET1

BACKGROUND

Prostate cancer (PCa) is one of the common malignant tumors worldwide. MiR-183-5p has been reported involved in the initiation of human PCa, this study aimed to investigate whether miR-183-5p affects the development of prostate cancer.

METHODS

In this study, we analyzed the expression of miR-183-5p in PCa patients and its correlation with clinicopathological parameters based on TCGA data portal. CCK-8, migration assay and invasion and wound-healing assay were performed to detect proliferation, migration and invasion in PCa cells.

RESULTS

We found the expression of miR-183-5p was significantly increased in PCa tissues, and high expression of miR-183 was positively associated with poor prognosis of PCa patients. Over-expression of miR-183-5p promoted the migration, invasion capacities of PCa cells, whereas knockdown of miR-183-5p showed reversed function. Furthermore, luciferase reporter assay showed TET1 was identified as a direct target of miR-183-5p, which was negatively correlation with miR-183-5p expression level. Importantly, rescue experiments demonstrated TET1 over-expression could reverse miR-183-5p mimic induced-acceleration of PCa malignant progression.

CONCLUSION

Our results indicated that miR-183-5p could act as a tumor promoter in PCa and it accelerated the malignant progression of PCa by directly targeting and down-regulating TET1.

Characterization of proteins, mRNAs, and miRNAs of circulating extracellular vesicles from prostate cancer patients compared to healthy subjects

Prostate cancer (PC) is the fifth leading cause of death in men globally. Measurement of the blood PSA level is still considered the gold-standard biomarker test for PC despite its high rate of delivering false positives and negatives that result in an inappropriate medical response, including overtreatment. We collected extracellular vesicles (EVs) from the blood plasma of PC patients with organ-confined, extracapsular-invading, and seminal vesicle-invading tumors and from healthy subjects. We examined the protein, mRNA, and miRNA content of these EVs using mass spectrometry (MS), a human PC PCR array, and a miScript miRNA PCR array, respectively. The proteomic analysis showed distinct groups of proteins that are differently expressed in each group of patients, as well as in healthy subjects. Samples from healthy subjects and each tumor type were used for both mRNA and miRNA arrays. The mRNA analysis showed distinct groups of mRNAs that were overexpressed in healthy or in one of the three tumor types but not in the EVs of the other groups. The miRNA analysis showed distinct groups of miRNAs as well. The fold of regulation in the expression of the identified mRNA and miRNA of each stage of the disease from healthy subjects showed that various mRNAs and miRNAs could discriminate the disease stage. Overall, our data suggest many molecular marker candidates for distinguishing between healthy subjects and PC patients using the cargo of circulating vesicles, as well as markers to discriminate between the different tumor types. Once verified, these markers might have a diagnostic value for PC.

Hsa-miR-183-5p Modulates Cell Adhesion by Repression of ITGB1 Expression in Prostate Cancer

Prostate cancer is a major health problem worldwide. MiR-183 is an oncomiR and a candidate biomarker in prostate cancer, affecting various pathways responsible for disease initiation and progression. We sought to discover the most relevant processes controlled by miR-183 through an unbiased transcriptomic approach using prostate cell lines and patient tissues to identify miR-183 responsive genes and pathways. Gain of function experiments, reporter gene assays, and transcript and protein measurements were conducted to validate predicted functional effects and protein mediators. A total of 135 candidate miR-183 target genes overrepresenting cell adhesion terms were inferred from the integrated transcriptomic analysis. Cell attachment, spreading assays and focal adhesion quantification of miR-183-overexpressing cells confirmed the predicted reduction in cell adhesion. ITGB1 was validated as a major target of repression by miR-183 as well as a mediator of cell adhesion in response to miR-183. The reporter gene assay and PAR-CLIP read mapping suggest that ITGB1 may be a direct target of miR-183. The negative correlation between miR-183 and ITGB1 expression in prostate cancer cohorts supports their interaction in the clinical set. Overall, cell adhesion was uncovered as a major pathway controlled by miR-183 in prostate cancer, and ITGB1 was identified as a relevant mediator of this effect.

Recent Advances in the Management of Hormone-Sensitive Oligometastatic Prostate Cancer

After primary treatment for prostate cancer with either radical prostatectomy or radiotherapy, a significant proportion of patients are at risk of developing metastases. In recent years, a deeper understanding of the underlying biology together with improved imaging techniques and the advent of new therapeutic options including metastases-directed therapies and new drugs have revolutionized the management of low-burden metastatic disease, also known as oligometastatic state. The purpose of this narrative review is to report the recent developments in the management of hormone-sensitive oligometastatic prostate cancer patients.

Regulation of Neuroendocrine-like Differentiation in Prostate Cancer by Non-Coding RNAs

Neuroendocrine prostate cancer (NEPC) represents a variant of prostate cancer that occurs in response to treatment resistance or, to a much lesser extent, de novo. Unravelling the molecular mechanisms behind transdifferentiation of cancer cells to neuroendocrine-like cancer cells is essential for development of new treatment opportunities. This review focuses on summarizing the role of small molecules, predominantly microRNAs, in this phenomenon. A published literature search was performed to identify microRNAs, which are reported and experimentally validated to modulate neuroendocrine markers and/or regulators and to affect the complex neuroendocrine phenotype. Next, available patients’ expression datasets were surveyed to identify deregulated microRNAs, and their effect on NEPC and prostate cancer progression is summarized. Finally, possibilities of miRNA detection and quantification in body fluids of prostate cancer patients and their possible use as liquid biopsy in prostate cancer monitoring are discussed. All the addressed clinical and experimental contexts point to an association of NEPC with upregulation of miR-375 and downregulation of miR-34a and miR-19b-3p. Together, this review provides an overview of different roles of non-coding RNAs in the emergence of neuroendocrine prostate cancer.

miR-148a, miR-152 and miR-200b promote prostate cancer metastasis by targeting DNMT1 and PTEN expression

MicroRNAs (miRs) modulate the expression of target genes in the signal pathway on transcriptome level. The present study investigated the ‘epigenetic-based miRNA (epi-miRNA)-mRNA’ regulatory network of miR-34b, miR-34c, miR-148a, miR-152, miR-200a and miR-200b epi-miRNAs and their target genes, DNA methyltransferase (DNMT1, 3a and 3b), phosphate and tensin homolog (PTEN) and NK3 Homeobox 1 (NKX3.1), in prostate cancer (PCa) using reverse transcription-quantitative PCR. The expression level of NKX3.1 were not significantly different between the PCa, Met-PCa and control groups. However, in the PCa and Met-PCa groups, the expression level of DNMT1 was upregulated, while DNMT3a, DNMT3b and PTEN were downregulated. Overexpression of DNMT1 (~5 and ~6-fold increase in the PCa and Met-PCa groups respectively) was accompanied by a decreased expression in PTEN, indicating a potential negative association. Both groups indicated that a high level of DNMT1 is associated with the aggressiveness of cancer, and there is a a directly proportional relationship between this gene and PSA, GS and TNM staging. A significant ~2 to ~5-fold decrease in the expression levels of DNMT3a and DNMT3b was found in both groups. In the PCa group, significant associations were identified between miR-34b and DNMT1/DNMT3b; between miR-34c/miR-148a and all target genes; between miR-152 and DNMT1/DNMT3b and PTEN; and between miR-200a/b and DNMT1. In the Met-PCa group, miR-148a, miR-152 and miR-200b exhibited a significant association with all target genes. A significant negative association was identified between PTEN and DNMT1 in the Met-PCa group. It was also revealed that that miR-148a, miR-152 and miR-200b increased the expression of DNMT1 and suppressed PTEN. Furthermore, the ‘epi-miRNA-mRNA’ bidirectional feedback loop was emphasised and the methylation pattern in PCa anti-cancer therapeutics was highlighted.

miR-425-5p as an exosomal biomarker for metastatic prostate cancer

Prostate cancer-related deaths are mostly caused by metastasis, which indicates the importance of identifying clinical prognostic biomarkers. In this study, we evaluated the expression profile of exosomal microRNAs (miRNAs) derived from metastatic prostate cancer (mPCa) cell lines (LNCaP and PC-3). miRNA signatures in exosomes and cells were evaluated by miRNA microarray analysis. Fourteen miRNAs were identified as candidates for specific noninvasive biomarkers. The expression of five miRNAs was validated using RT-qPCR, which confirmed that miR-205-5p, miR-148a-3p, miR-125b-5p, miR-183-5p, and miR-425-5p were differentially expressed in mPCa exosomes. Bioinformatic analyses showed that miR-425-5p was associated with residual tumor, pathologic T and N stages, and TP53 status in PCa samples. Gene ontology analysis of negatively correlated and predicted targeted genes showed enrichment of genes related to bone development pathways. The LinkedOmics database indicated that the potential target HSPB8 has a significant negative correlation with miR-425-5p. In conclusion, this study identified a panel of exosomal miRNAs with potential value as prognostic biomarkers for prostate cancer.

Exploring miRNA Signature and Other Potential Biomarkers for Oligometastatic Prostate Cancer Characterization: The Biological Challenge behind Clinical Practice. A Narrative Review

Simple Summary

The oligometastatic prostate cancer state is defined as the presence of a number of lesions ≤ 5 and has been significantly correlated with better survival if compared to a number of metastases > 5. In particular, patients in an oligometastatic setting could benefit from a metastates directed therapy, which could control the disease delaying the start of systemic therapies. For this reason, the selection of true-oligometastatic patients who could benefit from such approach is particularly important in this setting. The aim of the present narrative review is to report the current state of the art on the liquid biopsy-derived analytes and their reliability as biomarkers in the clinics for the identification of true-oligometastatic patients. This kind of molecular profiling could refine current developments in the era of precision oncology allowing patients’ stratification and leading to more refined therapeutic strategies.

Abstract

In recent years, a growing interest has been directed towards oligometastatic prostate cancer (OMPC), as patients with three to five metastatic lesions have shown a significantly better survival as compared with those harboring a higher number of lesions. The efficacy of local ablative treatments directed on metastatic lesions (metastases-directed treatments) was extensively investigated, with the aim of preventing further disease progression and delaying the start of systemic androgen deprivation therapies. Definitive diagnosis of prostate cancer is traditionally based on histopathological analysis. Nevertheless, a bioptic sample—static in nature—inevitably fails to reflect the dynamics of the tumor and its biological response due to the dynamic selective pressure of cancer therapies, which can profoundly influence spatio-temporal heterogeneity. Furthermore, even with new imaging technologies allowing an increasingly early detection, the diagnosis of oligometastasis is currently based exclusively on radiological investigations. Given these premises, the development of minimally-invasive liquid biopsies was recently promoted and implemented as predictive biomarkers both for clinical decision-making at pre-treatment (baseline assessment) and for monitoring treatment response during the clinical course of the disease. Through liquid biopsy, different biomarkers, commonly extracted from blood, urine or saliva, can be characterized and implemented in clinical routine to select targeted therapies and assess treatment response. Moreover, this approach has the potential to act as a tissue substitute and to accelerate the identification of novel and consistent predictive analytes cost-efficiently. However, the utility of tumor profiling is currently limited in OMPC due to the lack of clinically validated predictive biomarkers. In this scenario, different ongoing trials, such as the RADIOSA trial, might provide additional insights into the biology of the oligometastatic state and on the identification of novel biomarkers for the outlining of true oligometastatic patients, paving the way towards a wider ideal approach of personalized medicine. The aim of the present narrative review is to report the current state of the art on the solidity of liquid biopsy-related analytes such as CTCs, cfDNA, miRNA and epi-miRNA, and to provide a benchmark for their further clinical implementation. Arguably, this kind of molecular profiling could refine current developments in the era of precision oncology and lead to more refined therapeutic strategies in this subset of oligometastatic patients.

Vinculin orchestrates prostate cancer progression by regulating tumor cell invasion, migration, and proliferation

BACKGROUND

Prostate cancer (PCa) is a leading cause of death in men, and effective treatment of PCa requires further development. Our study aimed to investigate the potential role of vinculin (VCL) in PCa progression in vitro and in vivo.

METHODS

We investigated the methylation level of the VCL promoter based on the TCGA database. The knockdown efficacy of VCL gene expression was confirmed by quantitative polymerase chain reaction, Western blot analysis, and immunofluorescence. Furthermore, morphological changes in PCa cells were detected using phalloidin staining. The mobility of PCa cells was measured using transwell assays and high-content analysis. Moreover, cell growth and viability were determined using the colony formation and cell counting kit-8 assays. The role of VCL in tumor growth in vivo was investigated using a subcutaneous xenograft model generated by injecting tumor cells into the right flank of BALB/c nude mice.

RESULTS

The methylation level of the VCL promoter in PCa was significantly downregulated concomitant with age and the progression of nodal metastasis. VCL expression was markedly decreased by shRNA. Importantly, VCL knockdown significantly changed the cell morphology; inhibited the migration, invasion, and movement; and repressed colony formation and viability of PCa cells in vitro. Furthermore, downregulation of VCL suppressed tumor growth in vivo.

CONCLUSIONS

Our study comprehensively evaluated the role of VCL in PCa progression in vivo and in vitro. The findings of the present study suggest that VCL can be a potential target for PCa prognosis and treatment.

Peripheral Blood Cells from Patients with Hodgkin's and Diffuse Large B Cell Lymphomas May Be a Better Source of Candidate Diagnostic miRNAs Than Circulating miRNAs

Hodgkin lymphoma (HL) and diffuse large B cell lymphoma (DLBCL) represent 15% and 20%, respectively, of all lymphoma types. The aim of this study was to identify and compare circulating serum miRNA (c-miRNA) and peripheral whole blood miRNA (wb-miRNA) profiles in patients with these lymphomas. Serum samples (20 HL, 21 DLBCL, and 30 healthy controls) and whole blood samples (21 HL, 17 DLBCL patients, and 30 healthy controls) were collected at the time of diagnosis. Serum and whole blood were also collected from 18 HL/17 DLBCL and eight HL/nine DLBCL patients, respectively, after treatment. Pairwise comparisons identified 125 c-miRNAs (adjusted P value < 0.05) showing significant dysregulation between 30 healthy controls and patients; of these, 47 and 55 differentiated controls from pretherapeutic HL and DLBCL patients, respectively. In addition, 60 and 16 c-miRNAs differentiated controls from posttherapeutic HL and DLBCL, respectively. Pairwise comparisons identified 292 wb-miRNAs (adjusted P value < 0.05) showing significant dysregulation between 30 controls and patients; of these, 103 and 169 differentiated controls from pretherapeutic HL and DLBCL, respectively, and 142 and 151 wb-miRNAs differentiated controls from posttherapeutic HL and DLBCL, respectively. Thus, lymphoma-associated miRNAs may be a better source of noninvasive candidate biomarkers than miRNAs in serum. It is unclear whether miRNA alterations in lymphoma cells are similar to those observed in white blood cells.

Plasma hsa_circ_0027089 is a diagnostic biomarker for hepatitis B virus-related hepatocellular carcinoma

Circular RNAs (circRNAs) have recently been identified as a new member of endogenous noncoding RNAs. CircRNAs exhibit high stability and can thus can be used as valuable biomarkers for monitoring the occurrence and development of hepatocellular carcinoma (HCC). The present study sought to explore the diagnostic significance of plasma circRNAs in hepatitis B virus (HBV)-related HCC. Plasma circRNAs from 10 patients with hepatitis B (HBV)-related HCC and 5 patients with HBV-related liver cirrhosis were investigated by microarray to screen differentially expressed circRNAs, 157 upregulated and 161 downregulated circRNAs were found. Twenty-four circRNAs were further investigated via quantitative reverse-transcriptase–polymerase chain reaction assay in a training cohort (n = 48), hsa_circ_0027089 exhibited the highest significance and further distinguished 64 HCC patients from 40 cirrhosis patients and 72 healthy participants in a validation cohort. These results indicate that plasma hsa_circ_0027089 can serve as a new marker for the diagnosis of HBV-related HCC.

MiR-93/miR-375: Diagnostic Potential, Aggressiveness Correlation and Common Target Genes in Prostate Cancer

Dysregulation of miRNAs has a fundamental role in the initiation, development and progression of prostate cancer (PCa). The potential of miRNA in gene therapy and diagnostic applications is well documented. To further improve miRNAs’ ability to distinguish between PCa and benign prostatic hyperplasia (BPH) patients, nine miRNA (-21, -27b, -93, -141, -205, -221, -182, -375 and let-7a) with the highest reported differentiation power were chosen and for the first time used in comparative studies of serum and prostate tissue samples. Spearman correlations and response operating characteristic (ROC) analyses were applied to assess the capability of the miRNAs present in serum to discriminate between PCa and BPH patients. The present study clearly demonstrates that miR-93 and miR-375 could be taken into consideration as single blood-based non-invasive molecules to distinguish PCa from BPH patients. We indicate that these two miRNAs have six common, PCa-related, target genes (CCND2, MAP3K2, MXI1, PAFAH1B1, YOD1, ZFYVE26) that share the molecular function of protein binding (GO:0005515 term). A high diagnostic value of the new serum derived miR-182 (AUC = 0.881, 95% confidence interval, CI = 0.816–0.946, p < 0.0001, sensitivity and specificity were 85% and 79%, respectively) is also described.

Comparative analysis of epi-miRNA expression levels in local/locally advanced and metastatic prostate cancer patients

Abnormal expression of enzymes involved in epigenetic mechanisms, such as DNA methyl transferases, can trigger large chaos in cellular gene expression networks and eventually lead to cancer progression. In our study, which is a pioneer in the literature that clinicopathologically evaluates the expression of 30 epi-miRNAs in prostate cancer (PCa), we investigated which of the new miRNA class epi-miRNAs could be an effective biomarker in the diagnosis and progression of PCa. In this study, the expression levels of 30 epi-miRNAs in whole blood samples from 25 control, 25 PCa and 40 metastatic PCa patients were investigated by the Quantitative Real-Time PCR method. Then, promoter methylation levels of 11 epi-miRNAs, whose expression levels were found to be significantly higher, were examined by methylation-specific qPCR method. The correlations between miRNA expression levels and clinicopathological parameters (Gleason Score (GS), PSA levels, TNM Staging) in different stages of PCa groups as well as disease-specific expression levels were examined. We found a hypomethylation in the promoter regions of miRNAs that showed a direct proportional increase with PSA levels (miR-34b/c, miR-148a, miR-152), GS's (miR-34a-5p, miR-34b/c, miR-101-2, miR-126, miR-148a, miR- 152, miR-185-5p) and T staging (miR-34a-5p, miR-34b/c, miR-101-2, miR-126, miR-140, miR-148a, miR-152, miR-185-5p) (p < 0.05). When miR-200a/b was evaluated according to clinicopathological parameters, it acted as an onco-miR in local/local advanced PCa and as a tumor-suppressor-miR in metastatic stage. This study is novel in the sense that our findings draw attention to the important role of miRNAs as diagnostic and prognostic biomarkers in PCa.

Differences between Well-Differentiated Neuroendocrine Tumors and Ductal Adenocarcinomas of the Pancreas Assessed by Multi-Omics Profiling

Most pancreatic neuroendocrine tumors (PNETs) are indolent, while pancreatic ductal adenocarcinomas (PDACs) are particularly aggressive. To elucidate the basis for this difference and to establish the biomarkers, by using the deep sequencing, we analyzed somatic variants across coding regions of 409 cancer genes and measured mRNA/miRNA expression in nine PNETs, eight PDACs, and four intestinal neuroendocrine tumors (INETs). There were 153 unique somatic variants considered pathogenic or likely pathogenic, found in 50, 57, and 24 genes in PDACs, PNETs, and INETs, respectively. Ten and 11 genes contained a pathogenic mutation in at least one sample of all tumor types and in PDACs and PNETs, respectively, while 28, 34, and 11 genes were found to be mutated exclusively in PDACs, PNETs, and INETs, respectively. The mRNA and miRNA transcriptomes of PDACs and NETs were distinct: from 54 to 1659 differentially expressed mRNAs and from 117 to 250 differentially expressed miRNAs exhibited high discrimination ability and resulted in models with an area under the receiver operating characteristics curve (AUC-ROC) >0.9 for both miRNA and mRNA. Given the miRNAs high stability, we proposed exploring that class of RNA as new pancreatic tumor biomarkers.

Challenges in Cancer Biomarker Discovery Exemplified by the Identification of Diagnostic MicroRNAs in Prostate Tissues

Identification and clinical translation of routinely tested biomarkers require a complex and multistep workflow. Here, we described a confirmatory process estimating the utility of previously identified candidate tissue miRNAs for diagnosis of prostate cancer (PCa). RNA was isolated from formalin-fixed paraffin-embedded (FFPE) prostate tissue surgically resected from 44 patients with PCa and 24 patients with benign prostate hyperplasia (BPH). Of the 92 RNA samples obtained, 68 represented 42 malignant (PCa) areas and 26 represented nonmalignant (PCa 0%) areas of the prostate tissue sections. The levels of miR-32-5p, miR-183-5p, miR-141-5p, miR-187-3p, miR-375, miR-663b, miR-615-3p, miR-205-5p, miR-221-3p, and miR-222-3p were evaluated using Exiqon chemistry. Five (miR-32-5p, miR-141-5p, miR-187-3p, miR-375, and miR-615-3p), one (miR-32-5p), and two (miR-32-5p and miR-141-5p) miRNAs discriminated between BPH and areas of cancer-bearing prostate tissue harboring different numbers of cancer cells (PCa 15–70%, PCa 2–10%, and PCA 0%, respectively), with an area under the receiver operating characteristics curve (AUC-ROC) > 0.9. Only miRNA 32-5p discriminated BPH specimens from sections of cancer-bearing prostate tissue with a low percentage, a high percentage, or no dysplastic cells. miR-32-5p could be considered as potential diagnostic biomarker discriminating BPH from noncancerous areas within cancer-bearing prostate tissue. However, further clinical studies are warranted to confirm its diagnostic utility.

For Physicians Managing Voiding Dysfunction, Improving the Detection Rate of Early Prostate Cancer and Discrimination From Benign Prostatic Hyperplasia, in a Molecular Biomarker Aspects

Prostate cancer (CaP) is the most common cancer diagnosed among men in the United States and the fifth most common cancer among men in Korea. Unfortunately, the early stages of CaP may have no symptoms. Thus, early detection is very important and physicians managing voiding dysfunction must have awareness about CaP. The traditional tests used for early detection of CaP are the prostate-specific antigen (PSA) blood test and digital rectal examination. However, a high PSA level is not specific for CaP. Benign prostatic hyperplasia, prostatitis, urinary tract infection, and urinary retention can all cause a high PSA level. Thus, no test shows sufficient accuracy to truly be useful for screening men for CaP. A prostate biopsy is the only method that yields a definitive diagnosis of CaP; however, this test is invasive and uncomfortable. Recently, new biomarkers for CaP detection have been proposed to improve the accuracy of the PSA test. In this review, we summarize our knowledge of various new biomarkers, including PSA-associated biomarkers (the prostate health index and 4Kscore), molecular biomarkers (PCA3, TMPRSS2: ERG fusion gene, and various miRNAs), and proteomics-associated biomarkers, and the ways in which they may improve the detection rate of CaP. Accordingly, this review can raise awareness about CaP to physicians managing voiding dysfunction and be a good reference for them.

Functional roles and potential clinical application of miRNA-345-5p in prostate cancer

BACKGROUND

MicroRNAs (miRNAs) are small non-coding RNAs, which negatively regulate gene expression and impact prostate cancer (PCa) growth and progression. Circulating miRNAs are stable and detectable in cell-free body fluids, such as serum. Investigation of circulating miRNAs presents great potential in uncovering new insights into the roles of miRNAs in PCa diagnosis and therapy.

METHODS

Using TaqMan miRNA quantitative reverse transcription polymerase chain reaction (RT-qPCR), we compared the expression levels of five miRNAs (miR-193a-3p, miR-9-3p, miR-335-5p, miR-330-3p, and miR-345-5p) in serum samples from 20 normal individuals without cancer, 25 patients with localized disease, 25 patients with hormone-naïve or hormone sensitive metastatic disease, and 25 patients with metastatic castration-resistant prostate cancer (CRPC). These five miRNAs were identified as potential oncogenes in our previous studies. MiR-345-5p was further investigated for its functional roles in CRPC cells.

RESULTS

We discovered that miR-9-3p, miR-330-3p-3p, and miR-345-5p were significantly overexpressed in serum from PCa patients when compared to serum from individuals without cancer. No differential expression patterns were observed between different disease categories. However, patients who were in remission after androgen deprivation therapy (ADT) appeared to have significantly lower miR-345-5p levels compared to the rest of the groups. We further demonstrated that miR-345-5p promotes CRPC cell growth and migration in vitro and validated that CDKN1A (the gene encoding p21) is the direct target of miR-345-5p.

CONCLUSIONS

Our results set the stage for a further investigation on the potential application of circulating miR-345-5p as a biomarker for PCa diagnosis and therapeutic response. The oncogenic roles of miR-345-5p through targeting CDKN1A render it a potential therapeutic target for PCa.

Downregulation of MicroRNA eca-mir-128 in Seminal Exosomes and Enhanced Expression of CXCL16 in the Stallion Reproductive Tract Are Associated with Long-Term Persistence of Equine Arteritis Virus

Equine arteritis virus (EAV) can establish long-term persistent infection in the reproductive tract of stallions and is shed in the semen. Previous studies showed that long-term persistence is associated with a specific allele of the CXCL16 gene (CXCL16S) and that persistent infection is maintained despite the presence of a local inflammatory and humoral and mucosal antibody responses. In this study, we demonstrated that equine seminal exosomes (SEs) are enriched in a small subset of microRNAs (miRNAs). Most importantly, we demonstrated that long-term EAV persistence is associated with the downregulation of an SE-associated miRNA (eca-mir-128) and with an enhanced expression of CXCL16 in the reproductive tract, a putative target of eca-mir-128. The findings presented here suggest that SE eca-mir-128 is implicated in the regulation of the CXCL16/CXCR6 axis in the reproductive tract of persistently infected stallions, a chemokine axis strongly implicated in EAV persistence. This is a novel finding and warrants further investigation to identify its specific mechanism in modulating the CXCL16/CXCR6 axis in the reproductive tract of the EAV long-term carrier stallion.IMPORTANCE Equine arteritis virus (EAV) has the ability to establish long-term persistent infection in the stallion reproductive tract and to be shed in semen, which jeopardizes its worldwide control. Currently, the molecular mechanisms of viral persistence are being unraveled, and these are essential for the development of effective therapeutics to eliminate persistent infection. Recently, it has been determined that long-term persistence is associated with a specific allele of the CXCL16 gene (CXCL16S) and is maintained despite induction of local inflammatory, humoral, and mucosal antibody responses. This study demonstrated that long-term persistence is associated with the downregulation of seminal exosome miRNA eca-mir-128 and enhanced expression of its putative target, CXCL16, in the reproductive tract. For the first time, this study suggests complex interactions between eca-mir-128 and cellular elements at the site of EAV persistence and implicates this miRNA in the regulation of the CXCL16/CXCR6 axis in the reproductive tract during long-term persistence.

Role of Stromal Paracrine Signals in Proliferative Diseases of the Aging Human Prostate

Androgens are essential for the development, differentiation, growth, and function of the prostate through epithelial–stromal interactions. However, androgen concentrations in the hypertrophic human prostate decrease significantly with age, suggesting an inverse correlation between androgen levels and proliferative diseases of the aging prostate. In elderly males, age- and/or androgen-related stromal remodeling is spontaneously induced, i.e., increased fibroblast and myofibroblast numbers, but decreased smooth muscle cell numbers in the prostatic stroma. These fibroblasts produce not only growth factors, cytokines, and extracellular matrix proteins, but also microRNAs as stromal paracrine signals that stimulate prostate epithelial cell proliferation. Surgical or chemical castration is the standard systemic therapy for patients with advanced prostate cancer. Androgen deprivation therapy induces temporary remission, but the majority of patients eventually progress to castration-resistant prostate cancer, which is associated with a high mortality rate. Androgen deprivation therapy-induced stromal remodeling may be involved in the development and progression of castration-resistant prostate cancer. In the tumor microenvironment, activated fibroblasts stimulating prostate cancer cell proliferation are called carcinoma-associated fibroblasts. In this review, we summarize the role of stromal paracrine signals in proliferative diseases of the aging human prostate and discuss the potential clinical applications of carcinoma-associated fibroblast-derived exosomal microRNAs as promising biomarkers.