Suggesting Tissue-Specific MSMB Gene Promoter as a Novel Approach for Prostate Targeted Gene Therapy.

BACKGROUND AND AIM: Prostate cancer is the second most common cancer among men that has affected their quality of life. This study aimed to find prostate tissue-specific genes using bioinformatics methods to specifically target prostate cells in case of metastasis to other tissues. MATERIALS AND METHODS: In this study, after finding a specific gene (MSMB)  that is highly expressed in cancer, the optimal promoter region of this gene was isolated and inserted in an expression vector. Then, this vector was transfected into two prostate cancer cell lines (DU145 and LNCaP) and three non-prostate cell lines  (LX-2, MRC-5, and U87) using the PEI chemical method. The expression of this vector in these cells was examined using fluorescent microscopy and flow cytometry. RESULTS: We observed that the expression of MSMB promoter in DU145 cell line has a much higher activity than the CMV promoter, which is a ubiquitous promoter. The MSMB promoter didn't show any activity in cells other than that of prostate derived cell lines. CONCLUSION: MSMB  gene promoter with specific expression and high efficiency in prostate tissue compared to CMV promoter can play an essential role in gene therapy of prostate cancer.

Prostate secretory protein 94 inhibits sterol binding and export by the mammalian CAP protein CRISP2 in a calcium-sensitive manner.

Members of the CAP protein superfamily are present in all kingdoms of life and have been implicated in many different processes, including pathogen defense, immune evasion, sperm maturation, and cancer progression. Most CAP proteins are secreted glycoproteins and share a unique conserved αßα sandwich fold. The precise mode of action of this class of proteins, however, has remained elusive. Saccharomyces cerevisiae has three CAP family members, termed pathogen related in yeast (Pry). We have previously shown that Pry1 and Pry2 export sterols in vivo and that they bind sterols in vitro. This sterol binding and export function of yeast Pry proteins is conserved in the mammalian CRISP proteins and other CAP superfamily members. CRISP3 is an abundant protein of the human seminal plasma and interacts with prostate secretory protein of 94 amino acids (PSP94), another major protein component in the seminal plasma. Here we examine whether the interaction between CRISP proteins and PSP94 affects the sterol binding function of CAP family members. We show that coexpression of PSP94 with CAP proteins in yeast abolished their sterol export function and the interaction between PSP94 and CAP proteins inhibits sterol binding in vitro. In addition, mutations that affect the formation of the PSP94-CRISP2 heteromeric complex restore sterol binding. Of interest, we found the interaction of PSP94 with CRISP2 is sensitive to high calcium concentrations. The observation that PSP94 modulates the sterol binding function of CRISP2 in a calcium-dependent manner has potential implications for the role of PSP94 and CRISP2 in prostate physiology and progression of prostate cancer.

A mouse testis serine protease, TESP1, as the potential SPINK3 receptor protein on mouse sperm acrosome.

Serine protease inhibitor Kazal type 3 (SPINK3) from mouse seminal vesicles is a Kazal-type trypsin inhibitor. It has been shown to bind to the sperm acrosome and modify sperm activity by influencing the sub-cellular Ca2+ influx. Previously, SPINK3 was reported to suppress in vitro sperm capacitation. However, under natural coitus, SPINK3 is removed from the mouse acrosome in the female reproductive tract, leading to successful fertilisation. Identification of the SPINK3 binding partner becomes essential to develop a contraceptive that works by prolonging the binding of SPINK3 to the sperm acrosome. We identified the SPINK3 receptor by using recombinant SPINK3 (rSPINK3). Testicular serine protease 1 (TESP1) was identified as the receptor for SPINK3 by 2D gel electrophoresis coupled with western blot analysis. To authenticate TESP1 as the receptor for SPINK3, sperm cells were incubated with TESP1 peptide antibody followed by determining the intracellular [Ca2+]i concentration by flow cytometry using Fluo-3 AM as a calcium probe. Furthermore, the 3D structures of SPINK3 and TESP1 were predicted by homology modelling (Schrodinger suite) using the crystal structure of pancreatic secretory trypsin inhibitor (PDB ID-1TGS) and human prostasin (PDB ID-3DFJ) as templates. The modelled protein structures were validated and subjected to molecular dynamics simulation (MDS) using GROMACS v5.0.5. Protein-protein docking was performed using HDOCK and the complex was validated by MDS. The results predicted that SPINK3 and TESP1 had strong binding affinity, with a dock score of -430.70 and 14 hydrogen bonds as key active site residues. If the binding affinity between SPINK3 and TESP1 could be increased, the SPINK3-TESP1 association will be prolonged, which will be helpful in the development of a male contraceptive.

Basal Cell Carcinoma of Prostate With MSMB-NCOA4 Fusion and a Probable Basal Cell Carcinoma In Situ: Case Report.

Basal cell carcinomas of prostate (BCCP) are very rare. Most arise in the transition zone and thus are associated with lower urinary tract symptoms and rarely associated with elevated prostate-specific antigen (PSA). These features make diagnosis/early diagnosis difficult because of the routine protocols followed. Basal cell carcinomas have distinctive histopathological, immunohistochemical, and to some extent also different molecular characteristics. Basal cell carcinoma in situ (BCCIS) is a nonexistent histological lesion as per the current literature, but here is an attempt to describe it through this case.A 74-year-old man presented with hematuria and previous diagnosis of prostatic hyperplasia. Based on this history, he underwent a prostatectomy ad modum Freyer. Pathological examination surprisingly revealed a diffusely infiltrative tumor with nonacinar adenocarcinoma morphology and many glandular structures probably representing BCCIS. Tumor was diagnosed as BCCP. Patient presented with metastasis to the abdominal wall 8 months postprostatectomy.BCCP is an aggressive type of prostate cancer, which might be challenging to diagnose based on routine protocols. This results in delayed diagnosis and treatment and thus poor prognosis. Furthermore, patients with this subtype of prostate cancer need appropriately designed, and maybe a totally different follow-up regimen as PSA is of no use for BCCP patients. Finally, diagnosis of BCCIS, if agreed upon its existence needs to be studied in larger cohorts as a precursor lesion.

Mouse model suggests limited role for human mesotrypsin in pancreatitis.

Mesotrypsin is a low-abundance human trypsin isoform with a unique evolutionary mutation that conferred resistance to trypsin inhibitors and restricted substrate specificity. Mesotrypsin degrades the serine protease inhibitor Kazal type 1 (SPINK1) and thereby might increase risk for pancreatitis. Here, we report a mouse model designed to test the role of mesotrypsin in pancreatitis. We introduced the human mesotrypsin evolutionary signature mutation into mouse cationic trypsinogen (isoform T7), resulting in a Gly to Arg change at the corresponding position 199. In biochemical experiments using purified proteins, the p.G199R T7 mutant recapitulated all salient features of human mesotrypsin. T7G199R mice developed normally with no spontaneous pancreatitis or other obvious phenotypic changes. Cerulein-induced acute pancreatitis in C57BL/6N and T7G199R mice showed similar severity with respect to inflammatory parameters and acinar cell necrosis while plasma amylase activity was higher in T7G199R mice. Neither SPINK1 degradation nor elevated intrapancreatic trypsin activation was apparent in T7G199R mice. The results indicate that in T7G199R mice the newly created mesotrypsin-like activity has no significant impact on cerulein-induced pancreatitis. The observations suggest that human mesotrypsin is unimportant for pancreatitis; a notion that is consistent with published human genetic studies.

Validation of prostate cancer risk variants rs10993994 and rs7098889 by CRISPR/Cas9 mediated genome editing.

GWAS have identified numerous SNPs associated with prostate cancer risk. One such SNP is rs10993994. It is located in the ß-microseminoprotein (MSMB) promoter region, mediates MSMB prostate secretion levels, and is linked to mRNA expression changes in both MSMB and the adjacent gene NCOA4. In addition, our previous work showed a second SNP, rs7098889, is in positive linkage disequilibrium with rs10993994 and associated with MSMB expression independent of rs10993994. Here, we generate a series of clones with single alleles removed by double guide RNA (gRNA) mediated CRISPR/Cas9 deletions, through which we demonstrate that each of these SNPs independently and greatly alters MSMB expression in an allele-specific manner. We further show that these SNPs have no substantial effect on the expression of NCOA4. These data demonstrate that a single SNP can have a large effect on gene expression and illustrate the importance of functional validation studies to deconvolute observed correlations. The method we have developed is generally applicable to test any SNP for which a relevant heterozygous cell line is available. AUTHOR SUMMARY: In pursuing the underlying biological mechanism of prostate cancer pathogenesis, scientists utilized the existence of common single nucleotide polymorphisms (SNPs) in the human genome as genetic markers to perform large scale genome wide association studies (GWAS) and have so far identified more than a hundred prostate cancer risk variants. Such variants provide an unbiased and systematic new venue to study the disease mechanism, and the next big challenge is to translate these genetic associations to the causal role of altered gene function in oncogenesis. The majority of these variants are waiting to be studied and lots of them may act in oncogenesis through gene expression regulation. To prove the concept, we took rs10993994 and its linked rs7098889 as an example and engineered single cell clones by allelic-specific CRISPR/Cas9 deletion to separate the effect of each allele. We observed that a single nucleotide difference would lead to surprisingly high level of MSMB gene expression change in a gene specific and cell-type specific manner. Our study strongly supports the notion that differential level of gene expression caused by risk variants and their associated genetic locus play a major role in oncogenesis and also highlights the importance of studying the function of MSMB encoded ß-MSP in prostate cancer pathogenesis.

Prostate cancer risk SNP rs10993994 is a trans-eQTL for SNHG11 mediated through MSMB.

How genome-wide association studies-identified single-nucleotide polymorphisms (SNPs) affect remote genes remains unknown. Expression quantitative trait locus (eQTL) association meta-analysis on 496 prostate tumor and 602 normal prostate samples with 117 SNPs revealed novel cis-eQTLs and trans-eQTLs. Mediation testing and colocalization analysis demonstrate that MSMB is a cis-acting mediator for SNHG11 (P < 0.01). Removing rs10993994 in LNCaP cell lines by CRISPR/Cas9 editing shows that the C-allele corresponds with an over 100-fold increase in MSMB expression and 5-fold increase in SNHG11 compared with the T-allele. Colocalization analysis confirmed that the same set of SNPs associated with MSMB expression is associated with SNHG11 expression (posterior probability of shared variants is 66.6% in tumor and 91.4% in benign). These analyses further demonstrate variants driving MSMB expression differ in tumor and normal, suggesting regulatory network rewiring during tumorigenesis.

A meta-analysis of influence of MSMB promoter rs10993994 polymorphisms on prostate cancer risk.

OBJECTIVE: The aim of this meta-analysis was to assess the association between beta-microseminoprotein gene (MSMB) rs10993994 polymorphism and prostate cancer (PCa) risk. MATERIALS AND METHODS: Relevant databases were searched to identify studies investigating the association between rs10993994 polymorphisms and the risk of PCa using allele contrast, recessive, dominant, and additive models. The assessment of the association was used by odds ratios (ORs) with 95% confidence intervals (CIs). Hardy-Weinberg equilibrium (HWE) was checked for each study. The sensitivity analysis and the assessment of publication bias were also performed. RESULTS: Six reports involving 13 eligible studies (a total of 11,385 PCa patients and 9,115 controls) were included in the meta-analysis. Our data revealed that the T allele of MSMB rs10993994 polymorphism was significantly associated with PCa in all subjects (allele contrast: OR=1.24, 95% CI=1.19-1.29, p<0.001). Similarly, for recessive, dominant, and additive genetic models, significant associations were also found (recessive: OR=1.40, 95% CI=1.30-1.51; dominant: OR=1.28, 95% CI=1.21-1.36; and additive: OR=1.56, 95% CI=1.44-1.70). Significant associations were also found in Caucasians. The data for Asians showed significant association in allele contrast and recessive, additive genetic models, whereas no statistical significance was found in the dominant genetic model. CONCLUSIONS: This study demonstrated a significant association between the MSMB rs10993994 polymorphisms and PCa risk. Further large-scale studies are warranted to confirm our findings.

Structural and molecular biology of PSP94: Its significance in prostate pathophysiology.

Prostate secretory protein of 94 amino acids (PSP94), primarily found in the prostatic secretion, was originally isolated and purified from human seminal plasma. PSP94 has several putative biological functions and is considered a marker of prostate cancer (PCa). Here, we review the structural-functional relationships of PSP94, address its fungicidal activity and role as an inhibitor of sperm motility and protection from female immune surveillance, and review its role in tumor suppression. We also review the diagnostic assays that are developed for PSP94 for use in the diagnosis of PCa and use of such tests in the differential diagnosis of PCa from benign prostatic hyperplasia (BPH).

MSMB gene rs10993994 polymorphism increases the risk of prostate cancer.

Genome-wide association studies (GWASs) identified microseminoprotein-ß (MSMB) gene rs10993994 polymorphism was significantly associated with prostate cancer (PC) risk. However, the association between MSMB gene rs10993994 polymorphism and PC risk remains controversial. Therefore, we performed a systematic review and meta-analysis by searching in the databases of PubMed, and Embase. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by using fixed-effect or random-effect models. A total of 11 publications containing 13 case-control studies for rs10993994 polymorphism were included in our analysis. Our data indicated that MSMB gene rs10993994 polymorphism was associated with an increased risk of PC. Stratification analyses of ethnicity suggested rs10993994 polymorphism increased the risk of PC among Caucasians, but not among Asians. In conclusion, this meta-analysis indicates that MSMB gene rs10993994 polymorphism increases the risk of PC.

Iron oxide nanoparticles modulate heat shock proteins and organ specific markers expression in mice male accessory organs.

With increased industrial utilization of iron oxide nanoparticles (Fe2O3-NPs), concerns on adverse reproductive health effects following exposure have been immensely raised. In the present study, the effects of Fe2O3-NPs exposure in the seminal vesicle and prostate gland were studied in mice. Mice were exposed to two different doses (25 and 50 mg/kg) of Fe2O3-NPs along with the control and analyzed the expressions of heat shock proteins (HSP60, HSP70 and HSP90) and organ specific markers (Caltrin, PSP94, and SSLP1). Fe2O3-NPs decreased food consumption, water intake, and organo-somatic index in mice with elevated iron levels in serum, urine, fecal matter, seminal vesicle and prostate gland. FTIR spectra revealed alterations in the functional groups of biomolecules on Fe2O3-NPs treatment. These changes are accompanied by increased lactate dehydrogenase levels with decreased total protein and fructose levels. The investigation of oxidative stress biomarkers demonstrated a significant increase in reactive oxygen species, nitric oxide, lipid peroxidation, protein carbonyl content and glutathione peroxidase with a concomitant decrement in the glutathione and ascorbic acid in the male accessory organs which confirmed the induction of oxidative stress. An increase in NADPH-oxidase-4 with a decrease in glutathione-S-transferase was observed in the seminal vesicle and prostate gland of the treated groups. An alteration in HSP60, HSP70, HSP90, Caltrin, PSP94, and SSLP1 expression was also observed. Moreover, accumulation of Fe2O3-NPs brought pathological changes in the seminal vesicle and prostate gland of treated mice. These findings provide evidence that Fe2O3-NPs could be an environmental risk factor for reproductive disease.

Overexpression and purification of folded domain of prostate cancer related proteins MSMB and PSA.

Overexpression of domains of a human protein using recombinant DNA technology has been challenging because individual domains intend to accumulate as non-soluble aggregate when expressed separately. Studies on identifying right sequences for a domain to be able to fold independently may help understand the folding pattern and underlying protein-engineering events to isolate the functional domains of a protein. In this report, individual domains of prostate cancer related biomarkers; MSMB and PSA were overexpressed in bacterial system and purified in their folded forms using affinity chromatography. The western blotting experiment using domain specific antibodies further confirmed these proteins. The designed nucleotide sequences domains were truncated using fold index software and folding were predicted by phyre2 and I-TASSER software. Other parameters were optimized for their overexpression and purification using Co-NTA affinity chromatography. Purified domains of each protein showed secondary structures such as α + ß type for PSA, α/ß and ß type for the each domains of PSA and MSMB respectively. This is the first report on producing PSA and MSMB individual domains in functional folded forms. This study may help produce the folded domain of many such proteins to be used for better diagnostic purpose.

Impact of Body Mass Index, Age, Prostate Volume, and Genetic Polymorphisms on Prostate-specific Antigen Levels in a Control Population.

UNLABELLED: Prostate-specific antigen (PSA) is still the cornerstone of prostate cancer (PCa) screening and diagnosis in both research and current clinical practice. Inaccuracy of PSA is partly due to the influence of a number of genetic, clinical, and biological factors modifying PSA blood levels. In the present study, we detailed the respective influence of each factor among age, body mass index (BMI), prostate volume, and five single-nucleotide polymorphisms-rs10788160 (10q26), rs10993994 (10q11), rs11067228 (12q24), rs17632542 (19q13.33), and rs2928679 (8p21)-on PSA values in a cohort of 1374 men without PCa. Our results show that genetic factors, when risk variants are combined, influence PSA levels with an effect size similar to that of BMI. Taken together, the respective correlations of clinical parameters and genetic parameters would make it possible to correct and adjust PSA values more effectively in each individual. These results establish the basis to understand and implement a more personalised approach for the interpretation of PSA blood levels in the context of PCa screening and diagnosis. PATIENT SUMMARY: Prostate-specific antigen (PSA) values in an individual may vary according to genetic predisposition. The effect size of this variation can be significant, comparable with those resulting from clinical characteristics. Personalised PSA testing should take this into account.

Altered intestinal functions and increased local inflammation in insulin-resistant obese subjects: a gene-expression profile analysis.

BACKGROUND: Metabolic alterations relevant to postprandial dyslipidemia were previously identified in the intestine of obese insulin-resistant subjects. The aim of the study was to identify the genes deregulated by systemic insulin resistance in the intestine of severely obese subjects. METHODS: Transcripts from duodenal samples of insulin-sensitive (HOMA-IR < 3, n = 9) and insulin-resistant (HOMA-IR > 7, n = 9) obese subjects were assayed by microarray (Illumina HumanHT-12). RESULTS: A total of 195 annotated genes were identified as differentially expressed between these two groups (Fold change > 1.2). Of these genes, 36 were found to be directly involved in known intestinal functions, including digestion, extracellular matrix, endocrine system, immunity and cholesterol metabolism. Interestingly, all differentially expressed genes (n = 8) implicated in inflammation and oxidative stress were found to be upregulated in the intestine of insulin-resistant compared to insulin-sensitive subjects. Metabolic pathway analysis revealed that several signaling pathways involved in immunity and inflammation were significantly enriched in differently expressed genes and were predicted to be activated in the intestine of insulin-resistant subjects. Using stringent criteria (Fold change > 1.5; FDR < 0.05), three genes were found to be significantly and differently expressed in the intestine of insulin-resistant compared to insulin-sensitive subjects: the transcripts of the insulinotropic glucose-dependant peptide (GIP) and of the ß-microseminoprotein (MSMB) were significantly reduced, but that of the humanin like-1 (MTRNR2L1) was significantly increased. CONCLUSION: These results underline that systemic insulin resistance is associated with remodeling of key intestinal functions. Moreover, these data indicate that small intestine metabolic dysfunction is accompanied with a local amplification of low-grade inflammatory process implicating several pathways. Genes identified in this study are potentially triggered throughout the development of intestinal metabolic abnormalities, which could contribute to dyslipidemia, a component of metabolic syndrome and diabetes.

PSP94, an upstream signaling mediator of prostasin found highly elevated in ovarian cancer.

Ovarian cancer is a leading cause of cancer death as diagnosis is frequently delayed to an advanced stage. Effective biomarkers and screening strategies for early detection are urgently needed. In the current study, we identify PSP94 as a key upstream factor in mediating prostasin (a protein previously reported to be overexpressed in ovarian cancer) signaling that regulates prostasin expression and action in ovarian cancer cells. PSP94 is overexpressed in ovarian cancer cell lines and patients, and is significantly correlated with prostasin levels. Signaling pathway analysis demonstrated that both PSP94 and prostasin, as potential upstream regulators of the Lin28b/Let-7 pathway, regulate Lin28b and its downstream partner Let-7 in ovarian cancer cells. Expression of PSP94 and prostasin show a strong correlation with the expression levels of Lin28b/Let-7 in ovarian cancer patients. Thus, PSP94/prostasin axis appears to be linked to the Lin28b/Let-7 loop, a well-known signaling mechanism in oncogenesis in general that is also altered in ovarian cancer. The findings suggest that PSP94 and PSP94/prostasin axis are key factors and potential therapeutic targets or early biomarkers for ovarian cancer.

Deletion of atbf1/zfhx3 in mouse prostate causes neoplastic lesions, likely by attenuation of membrane and secretory proteins and multiple signaling pathways.

The ATBF1/ZFHX3 gene at 16q22 is the second most frequently mutated gene in human prostate cancer and has reduced expression or mislocalization in several types of human tumors. Nonetheless, the hypothesis that ATBF1 has a tumor suppressor function in prostate cancer has not been tested. In this study, we examined the role of ATBF1 in prostatic carcinogenesis by specifically deleting Atbf1 in mouse prostatic epithelial cells. We also examined the effect of Atbf1 deletion on gene expression and signaling pathways in mouse prostates. Histopathologic analyses showed that Atbf1 deficiency caused hyperplasia and mouse prostatic intraepithelial neoplasia (mPIN) primarily in the dorsal prostate but also in other lobes. Hemizygous deletion of Atbf1 also increased the development of hyperplasia and mPIN, indicating a haploinsufficiency of Atbf1. The mPIN lesions expressed luminal cell markers and harbored molecular changes similar to those in human PIN and prostate cancer, including weaker expression of basal cell marker cytokeratin 5 (Ck5), cell adhesion protein E-cadherin, and the smooth muscle layer marker Sma; elevated expression of the oncoproteins phospho-Erk1/2, phospho-Akt and Muc1; and aberrant protein glycosylation. Gene expression profiling revealed a large number of genes that were dysregulated by Atbf1 deletion, particularly those that encode for secretory and cell membrane proteins. The four signaling networks that were most affected by Atbf1 deletion included those centered on Erk1/2 and IGF1, Akt and FSH, NF-κB and progesterone and ß-estradiol. These findings provide in vivo evidence that ATBF1 is a tumor suppressor in the prostate, suggest that loss of Atbf1 contributes to tumorigenesis by dysregulating membrane and secretory proteins and multiple signaling pathways, and provide a new animal model for prostate cancer.

Autophagy regulation in pancreatic acinar cells is independent of epidermal growth factor receptor signaling.

Autophagy is an intracellular degradation system in eukaryotic cells that occurs at a basal level. It can also be induced in response to environmental signals including nutrients, hormones, microbial pathogens, and growth factors, although the mechanism is not known in detail. We previously demonstrated that excessive autophagy is induced within pancreatic acinar cells deficient in Spink3, which is a trypsin inhibitor. SPINK1, the human homolog of murine Spink3, has structural similarity to epidermal growth factor (EGF), and can bind and stimulate the EGF receptor (EGFR). To analyze the role of the EGFR in pancreatic development, in the regulation of autophagy in pancreatic acinar cells, and in cerulein-induced pancreatitis, we generated and examined acinar cell-specific Egfr-deficient (Egfr(-/-)) mice. Egfr(-/-) mice showed no abnormalities in pancreatic development, induction of autophagy, or cerulein-induced pancreatitis, suggesting that Egfr is dispensable for autophagy regulation in pancreatic acinar cells.

Generation and analysis of serine protease inhibitor kazal type 3-cre driver mice.

Serine protease inhibitor Kazal type 1 (SPINK1; mouse homologue Spink3) was initially discovered as a trypsin-specific inhibitor in the pancreas. However, previous studies have suggested that SPINK1/Spink3 is expressed in a wide range of normal tissues and tumors, although precise characterization of its gene expression has not been described in adulthood. To further analyze Spink3 expression, we generated two mouse lines in which either lacZ or Cre recombinase genes were inserted into the Spink3 locus by Cre-loxP technology. In Spink3(lacZ) mice, ß-galactosidase activity was found in acinar cells of the pancreas and kidney, as well as epithelial cells of the bronchus in the lung, but not in the gastrointestinal tract or liver. Spink3(cre) knock-in mice were crossed with Rosa26 reporter (R26R) mice to monitor Spink3 promoter activity. In Spink3(cre);R26R mice, ß-galactosidase activity was found in acinar cells of the pancreas, kidney, lung, and a small proportion of cells in the gastrointestinal tract and liver. These data suggest that Spink3 is widely expressed in endoderm-derived tissues, and that Spink3(cre) knock-in mice are a useful tool for establishment of a conditional knockout mice to analyze Spink3 function not only in normal tissues, but also in tumors that express SPINK1/Spink3.

MSMB variation and prostate cancer risk: clues towards a possible fungal etiology.

BACKGROUND. With recent advances in high-throughput sequencing technologies, many prostate cancer risk loci have been identified, including rs10993994, a single nucleotide polymorphism (SNP) located near the MSMB gene. Variant allele (T) carriers of this SNP produce less prostate secretory protein 94 (PSP94), the protein product of MSMB, and have an increased risk of prostate cancer (approximately 25% per T allele), suggesting that PSP94 plays a protective role in prostate carcinogenesis, although the mechanisms for such protection are unclear. METHODS. We reviewed the literature on possible mechanisms for PSP94 protection for prostate cancer. RESULTS. One possible mechanism is tumor suppression, as PSP94 has been observed to inhibit cell or tumor growth in in vitro and in vivo models. Another novel mechanism, which we propose in this review article, is that PSP94 may protect against prostate cancer by preventing or limiting an intracellular fungal infection in the prostate. This mechanism is based on the recent discovery of PSP94's fungicidal activity in low-calcium environments (such as the cytosol of epithelial cells), and accumulating evidence suggesting a role for inflammation in prostate carcinogenesis. We provide further details of our proposed mechanism in this review article. CONCLUSIONS. To explore this mechanism, future studies should consider screening prostate specimens for fungi using the rapidly expanding number of molecular techniques capable of identifying infectious agents from the entire tree of life.

MALDI MS profiling of post-DRE urine samples highlights the potential of ß-microseminoprotein as a marker for prostatic diseases.

BACKGROUND: To use spectra acquired by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) from pre- and post-digital rectal examination (DRE) urine samples to search for discriminating peaks that can adequately distinguish between benign and malignant prostate conditions, and identify the peaks' underlying biomolecules. METHODS: Twenty-five participants with prostate cancer (PCa) and 27 participants with a variety of benign prostatic conditions as confirmed by a 10-core tissue biopsy were included. Pre- and post-DRE urine samples were prepared for MALDI MS profiling using an automated clean-up procedure. Following mass spectra collection and processing, peak mass and intensity were extracted and subjected to statistical analysis to identify peaks capable of distinguishing between benign and cancer. Logistic regression was used to combine markers to create a sensitive and specific test. RESULTS: A peak at m/z 10,760 was identified as ß-microseminoprotein (ß-MSMB) and found to be statistically lower in urine from PCa participants using the peak's average areas. By combining serum prostate-specific antigen (PSA) levels with MALDI MS-measured ß-MSMB levels, optimum threshold values obtained from Receiver Operator characteristics curves gave an increased sensitivity of 96% at a specificity of 26%. CONCLUSIONS: These results demonstrate that with a simple sample clean-up followed by MALDI MS profiling, significant differences of MSMB abundance were found in post-DRE urine samples. In combination with PSA serum levels, obtained from a classic clinical assay led to high classification accuracy for PCa in the studied sample set. Our results need to be validated in a larger multicenter prospective randomized clinical trial.