Syndecan Family Gene and Protein Expression and Their Prognostic Values for Prostate Cancer.

Prostate cancer (PCa) is the leading cause of cancer-associated mortality in men, and new biomarkers are still needed. The expression pattern and protein tissue localization of proteoglycans of the syndecan family (SDC 1-4) and syntenin-1 (SDCBP) were determined in normal and prostatic tumor tissue from two genetically engineered mouse models and human prostate tumors. Studies were validated using SDC 1-4 and SDCBP mRNA levels and patient survival data from The Cancer Genome Atlas and CamCAP databases. RNAseq showed increased expression of Sdc1 in Pb-Cre4/Ptenf/f mouse Pca and upregulation of Sdc3 expression and downregulation of Sdc2 and Sdc4 when compared to the normal prostatic tissue in Pb-Cre4/Trp53f/f-;Rb1f/f mouse tumors. These changes were confirmed by immunohistochemistry. In human PCa, SDC 1-4 and SDCBP immunostaining showed variable localization. Furthermore, Kaplan-Meier analysis showed that patients expressing SDC3 had shorter prostate-specific survival than those without SDC3 expression (log-rank test, p = 0.0047). Analysis of the MSKCC-derived expression showed that SDC1 and SDC3 overexpression is predictive of decreased biochemical recurrence-free survival (p = 0.0099 and p = 0.045, respectively), and SDC4 overexpression is predictive of increased biochemical recurrence-free survival (p = 0.035). SDC4 overexpression was associated with a better prognosis, while SDC1 and SDC3 were associated with more aggressive tumors and a worse prognosis.

Transcriptional regulators and regulatory pathways involved in prostate gland adaptation to a hypoandrogen environment.

Anti-androgen therapies, including orchiectomy, are effective at promoting prostate cancer remission, but are followed by progression to the more aggressive castration-resistant prostate cancer (CRPC). Castration promotes gland and tumor shrinkage. However, prostate adaptation to androgen deprivation involves striking parallel events, all requiring changes in gene expression. We hypothesized that transcription factors (TF) and other transcription-related genes are needed to orchestrate those changes. In this work, downstream analysis using bioinformatic tools and published microarray data allowed us to identify sixty transcriptional regulators (including 10 TF) and to integrate their function in physiologically relevant networks. Functional associations revealed a connection between Arnt, Bhlhe41 and Dbp circadian rhythm genes with the Ar circuitry and a small gene network centered in Pex14, which might indicate a previously unanticipated metabolic shift. We have also identified human homologs and mapped the corresponding genes to human chromosome regions commonly affected in prostate cancer, with particular attention to the PTEN/HHEX/MXI1 cluster at 10q23-25 (frequently deleted in PCa) and to MAPK1 at 22q11.21 (delete in intermediate risk but not in high risk PCa). Twenty genes were found mutated or with copy number alterations in at least five percent of three cancer cohorts and six of them (PHOX2A, NFYC, EST2, EIF2S1, SSRP1 and PARP1) associated with impacted patient survival. These changes are specific to the adaptation to the hypoandrogen environment and seem important for the progression to CRPC when mutated.

Heparanase-1 activity and the early postnatal prostate development.

Ventral prostate (VP) morphogenesis starts during embryonic development and continues for the first three postnatal weeks. Heparan sulfate (HS) affects paracrine signaling. Heparanase-1 (HPSE) is the only enzyme capable of cleaving HS. HPSE releases the HS bioactive fragment and mobilizes growth factors. Little is known, however, about HS turnover and HPSE function during VP morphogenesis. In this study, we measured HSPG expression and analyzed the expression and distribution of HPSE in the rat VP. HPSE was predominantly expressed by the VP epithelium. The VP was treated with heparin in ex vivo cultures to interfere with HS and resulted in delayed epithelial growth. Hpse knockdown using siRNA delayed epithelial growth in the first postnatal week ex vivo, which was similar to treating with the lower concentration of heparin. Hpse silencing was related to changes in HS chain length (as determined by size-exclusion chromatography, up-regulation of Mmp9, and down-regulation of Mmp2 expression). It also down-modulated ERK1/2 phosphorylation, suggesting a reduction in signaling, likely due to decreased HS cleavage and growth factor bioavailability. Our results showed that HPSE played a role in early epithelial growth during the first week of VP postnatal development. Developmental Dynamics 248:211-220, 2019. © 2019 Wiley Periodicals, Inc.

The role of SDF1 in prostate epithelial morphogenesis.

Androgens induce rat prostate induction from the urogenital sinus epithelium at embryonic day 17.5. Subsequent morphogenesis, including epithelial cord growth, branching, and canalization, results from concerted paracrine interactions with the stroma. A significant number of paracrine factors bind heparan sulfate (HS). We hypothesized that interfering with overall sulfation could disrupt the signaling mediated by HS-binding factors and that the undersulfated environment would allow investigation of individual exogenous morphogens. First, we investigated whether acinar morphogenesis involved HS-proteoglycan expression and found that syndecans 1 and 3 were upregulated in RWPE1 cells in the transition from two- to three-dimensional (3D) Matrigel, capable of promoting spheroid formation. We then investigated whether sodium chlorate, a general sulfation inhibitor, interfered with spheroid formation by RWPE1 cells and acinar morphogenesis in ex vivo ventral prostate (VP) organ culture. As expected, treatment with sodium chlorate inhibited spheroid formation by RWPE1 cells in 3D culture. Chlorate also inhibited ex vivo VP epithelial branching and canalization, resulting in long branchless epithelial structures. We then investigated whether the HS-binding factors, FGF10, TGFß1, and SDF1, could reverse the effect of sodium chlorate. Although no effect was seen in the FGF10- and TGFß1-treated samples, SDF1 promoted epithelial canalization in the low sulfated environment, highlighting its specific role in lumen formation. Altogether, the results show that sodium chlorate perturbed prostate morphogenesis and allowed investigation of factors involved in branching and/or canalization, implicating SDF1 signaling in epithelial canalization.

Menthol inhibits detrusor contractility independently of TRPM8 activation.

Agonists such as icilin and menthol can activate the cool temperature-sensitive ion channel TRPM8. However, biological responses to menthol may occur independently of TRPM8 activation. In the rodent urinary bladder, menthol facilitates the micturition reflex but inhibits muscarinic contractions of the detrusor smooth muscle. The site(s) of TRPM8 expression in the bladder are controversial. In this study we investigated the regulation of bladder contractility in vitro by menthol. Bladder strips from wild type and TRPM8 knockout male mice (25-30 g) were dissected free and mounted in organ baths. Isometric contractions to carbachol (1 nM-30 µM), CaCl2 (1 µM to 100 mM) and electrical field stimulation (EFS; 8, 16, 32 Hz) were measured. Strips from both groups contracted similarly in response to both carbachol and EFS. Menthol (300 µM) or nifedipine (1 µM) inhibited carbachol and EFS-induced contractions in both wild type and TRPM8 knockout bladder strips. Incubation with the sodium channel blocker tetrodotoxin (1 µM), replacement of extracellular sodium with the impermeant cation N-Methyl-D-Glucamine, incubation with a cocktail of potassium channel inhibitors (100 nM charybdotoxin, 1 µM apamin, 10 µM glibenclamide and 1 µM tetraethylammonium) or removal of the urothelium did not affect the inhibitory actions of menthol. Contraction to CaCl2 was markedly inhibited by either menthol or nifedipine. In cultured bladder smooth muscle cells, menthol or nifedipine abrogated the carbachol or KCl-induced increases in [Ca2+]i. Intravesical administration of menthol increased voiding frequency while decreasing peak voiding pressure. We conclude that menthol inhibits muscarinic bladder contractions through blockade of L-type calcium channels, independently of TRPM8 activation.

Transcription factors involved in prostate gland adaptation to androgen deprivation.

Androgens regulate prostate physiology, and exert their effects through the androgen receptor. We hypothesized that androgen deprivation needs additional transcription factors to orchestrate the changes taking place in the gland after castration and for the adaptation of the epithelial cells to the androgen-deprived environment, ultimately contributing to the origin of castration-resistant prostate cancer. This study was undertaken to identify transcription factors that regulate gene expression after androgen deprivation by castration (Cas). For the sake of comparison, we extended the analysis to the effects of administration of a high dose of 17ß-estradiol (E2) and a combination of both (Cas+E2). We approached this by (i) identifying gene expression profiles and enrichment terms, and by searching for transcription factors in the derived regulatory pathways; and (ii) by determining the density of putative transcription factor binding sites in the proximal promoter of the 10 most up- or down-regulated genes in each experimental group in comparison to the controls Gapdh and Tbp7. Filtering and validation confirmed the expression and localized EVI1 (Mecom), NFY, ELK1, GATA2, MYBL1, MYBL2, and NFkB family members (NFkB1, NFkB2, REL, RELA and RELB) in the epithelial and/or stromal cells. These transcription factors represent major regulators of epithelial cell survival and immaturity as well as an adaptation of the gland as an immune barrier in the absence of functional stimulation by androgens. Elk1 was expressed in smooth muscle cells and was up-regulated after day 4. Evi1 and Nfy genes are expressed in both epithelium and stroma, but were apparently not affected by androgen deprivation.

Desquamation is a novel phenomenon for collective prostate epithelial cell deletion after castration.

The mechanism underlying castration-induced prostate regression, which is a classical physiological concept translated into the therapeutic treatment of advanced prostate cancer, involves epithelial cell apoptosis. In searching for events and mechanisms contributing to prostate regression in response to androgen modulation, we have frequently observed the collective deletion of epithelial cells. This work was undertaken to characterize this phenomenon hereafter named desquamation and to verify its presence after 17ß-estradiol (E2) administration. Electron microscopy revealed that the desquamating cells had preserved cell-cell junctions and collapsed nuclear contents. The TUNEL reaction was negative for these cells, which were also negative for cleaved caspases-8, -9, -3 and nuclear apoptosis-inducing factor. Detailed analyses revealed that the condensed chromatin was first affected detaching from the nuclear lamina, which was observable after lamin A immunohistochemistry, suggesting the lack of lamin A degradation. A search in animals treated with supraphysiological E2 employed as an alternative anti-androgen treatment revealed no desquamation. The combined treatment (Cas + E2 group) caused changes particular to each treatment, including desquamation. In conclusion, desquamation appeared as a novel phenomenon contributing to collective prostate epithelial cell deletion, distinct from the classical castration-induced apoptosis and particular to the androgen deprivation resulting from surgical castration, and should be considered as part of the mechanisms promoting organ regression.