The Isoflavanoid (+)-PTC Regulates Cell-Cycle Progression and Mitotic Spindle Assembly in a Prostate Cancer Cell Line.

Prostate cancer is the second most common malignancy in men and the development of effective therapeutic strategies remains challenging when more advanced, androgen-independent or insensitive forms are involved. Accordingly, we have evaluated, using flow cytometry, confocal microscopy and image analysis, the anti-proliferative effects of (+)-2,3,9-trimethoxypterocarpan [(+)-PTC, 1] on relevant human prostate cancer cells as well as its capacity to control mitosis within them. In particular, the studies reported herein reveal that (+)-PTC exerts anti-proliferative activity against the PC-3 cell lines by regulating cell-cycle progression with mitosis being arrested in the prophase or prometaphase. Furthermore, it emerges that treatment of the target cells with this compound results in the formation of monopolar spindles, disorganized centrosomes and extensively disrupted γ-tubulin distributions while centriole replication remains unaffected. Such effects suggest (+)-PTC should be considered as a possible therapy for androgen-insensitive/independent prostate cancer.

Mechanisms of programmed cell death in the midgut and salivary glands from Bradysia hygida (Diptera: Sciaridae) during pupal-adult metamorphosis.

Programmed cell death is involved with the degeneration/remodeling of larval tissues and organs during holometabolous development. The midgut is a model to study the types of programmed cell death associated with metamorphosis because its structure while degenerating is a substrate for the formation of the adult organ. Another model is the salivary glands from dipteran because their elimination involves different cell death modes. This study aimed to investigate the models of programmed cell death operating during midgut replacement and salivary gland histolysis in Bradysia hygida. We carried out experiments of real-time observations, morphological analysis, glycogen detection, filamentous-actin localization, and nuclear acridine orange staining. Our findings allow us to establish that an intact actin cytoskeleton is required for midgut replacement in B. hygida and nuclear condensation and acridine orange staining precede the death of the larval cells. Salivary glands in histolysis present cytoplasmic blebbing, nuclear retraction, and acridine orange staining. This process can be partially reproduced in vitro. We propose that the larval midgut death involves autophagic and apoptotic features and apoptosis is a mechanism involved with salivary gland histolysis.

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.

Castration-induced prostate epithelial cell apoptosis results from targeted oxidative stress attack of M1142 -macrophages.

Prostate development and function are regulated by androgens. Epithelial cell apoptosis in response to androgen deprivation is caspase-9-dependent and peaks at Day 3 after castration. However, isolated epithelial cells survive in the absence of androgens. Znf142 showed an on-off expression pattern in intraepithelial CD68-positive macrophages, with the on-phase at Day 3 after castration. Rats treated with gadolinium chloride to deplete macrophages showed a significant drop in apoptosis, suggesting a causal relationship between macrophages and epithelial cell apoptosis. Intraepithelial M1-polarization was also limited to Day 3, and the inducible nitric oxide synthase (iNOS) knockout mice showed significantly less apoptosis than wild-type controls. The epithelial cells showed focal DNA double-strand breaks (DSB), 8-oxoguanine, and protein tyrosine-nitrosylation, fingerprints of exposure to peroxinitrite. Cultured epithelial cells induced M1-polarization and showed focal DSB and underwent apoptosis. The same phenomena were reproduced in LNCaP cells cocultured with Raw 264.7 macrophages. In conclusion, the M1 142 -macrophage (named after Znf142) attack causes activation of the intrinsic apoptosis pathway in epithelial cells after castration.

Desquamation takes center stage at the origin of proliferative inflammatory atrophy, epithelial-mesenchymal transition, and stromal growth in benign prostate hyperplasia.

In this commentary, we propose a relationship between desquamation, initially described as the collective detachment and deletion of epithelial cell in the prostate gland after castration, and proliferative inflammatory atrophy (PIA) and stromal growth in benign prostate hyperplasia (BPH). First, in response to diverse stimuli, including inflammatory mediators, epithelial cells desquamate and leave a large surface of the luminal side of the basement membrane (BM) exposed. Basal cells are activated into intermediate-type cells, which change morphology to cover and remodel the exposed BM (simple atrophy) to a new physiological demand (such as in the hypoandrogen environment, simulated by surgical and/or chemical castration) and/or to support re-epithelialization (under normal androgen levels). In the presence of inflammation (that might be the cause of desquamation), the intermediate-type cells proliferate and characterize PIA. Second, in other circumstances, desquamation is an early step of epithelial-to-mesenchymal transition (EMT), which contributes to stromal growth, as suggested by some experimental models of BPH. The proposed associations correlate unexplored cell behaviors and reveal the remarkable plasticity of the prostate epithelium that might be at the origin of prostate diseases.

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.

Neonatal exposure to high doses of 17ß-estradiol results in inhibition of heparanase-1 expression in the adult prostate.

Heparanase-1 (HPSE-1) is an endoglycosidase that cleaves heparan sulfate. The physiological functions of HPSE-1 include embryo development, hair growth, wound healing, tumor growth, angiogenesis, metastasis, and inflammation. HPSE-1 expression was found to increase temporarily in the rat ventral prostate (VP) after castration. The promoter region of the Hpse-1 gene has estrogen-responsive elements, suggesting that the gene is regulated by estrogens. In this study, we investigated the expression of HPSE-1 in the VP of 90-day-old rats after neonatal exposure to a high dose of 17ß-estradiol. HPSE-1 was not found by immunohistochemistry in the epithelium of estrogenized animals. To determine whether inhibition of Hpse-1 expression in the epithelium was due to pre- or post-transcriptional regulation, epithelial cells were isolated by centrifugation in Percoll gradient and the presence of Hpse-1 mRNA was investigated by RT-PCR. Hpse-1 mRNA was not detected in the estrogenized animals. Considering that Hpse-1 transcription could be inhibited by DNA methylation, we used the methylation-sensitive restriction enzyme HpaII and PCR to show that a single CCGG site at position +185 was more frequently methylated in the epithelium of estrogenized than in control animals. Immunohistochemistry for 5-methylcytidine revealed that the epithelial cell nuclei in estrogenized animals were heavily methylated. These results suggest that Hpse-1 expression was blocked in the epithelial cells of the VP, by estrogen imprinting by a pre-transcriptional mechanism involving DNA methylation.

MMP-2 contributes to the development of the mouse ventral prostate by impacting epithelial growth and morphogenesis.

Epithelial growth, branching, and canalization are important morphogenetic events of the rodent ventral prostate (VP) that take place during the first postnatal week. In this study, we evaluated the effect of knocking out MMP-2 (MMP-2(-/-)), by examining developmental and structural aspects of the VP in MMP-2(-/-) mice. Neonate (day 6) MMP-2(-/-) mice showed fewer epithelial tips, a lower epithelial cell proliferation rate, and also reticulin fiber accumulation. The VP of adult MMP-2(-/-) mice showed lower relative weight, smaller epithelial and smooth-muscle cell volume, and a larger amount of thicker reticulin fibers. No differences in cell proliferation or apoptotic index were noted between adult MMP-2(-/-) and wild-type mice. MMP-9 was found in the adult MMP-2(-/-), but not in the wild-type. In conclusion, MMP-2 function is essential for the epithelial morphogenesis of the mouse VP, and expression of MMP-9 is not sufficient for acquisition of the normal adult histology.

MMP-2 regulates rat ventral prostate development in vitro.

We have hypothesized that epithelial growth, branching, and canalization in the rodent ventral prostate (VP) would require matrix remodeling, and hence matrix metalloproteinase (MMP) activity. Therefore, the aim of this study was to evaluate the impact of blocking MMP-2, using whole organ culture. siRNA was employed to inhibit MMP-2 expression, and this was compared to GM6001's (a broad-spectrum MMP inhibitor) inhibition of general MMPs. These blocks impaired VP morphogenesis. MMP-2 silencing reduced organ size, epithelial area, and the number of tips, as well as caused a dilation of the distal parts of the epithelium. Histology, 3-D reconstruction, biochemistry, and second harmonic generation (SHG) revealed that MMP-2 silencing affected VP architecture by interfering in epithelial cell proliferation, lumen formation, and cellular organization of both epithelium and stroma, besides intense accumulation of collagen fibers. These data suggest that MMP-2 plays important roles in prostate growth, being directly involved with epithelial morphogenesis.

The Neurobiology of Zika Virus: New Models, New Challenges.

The Zika virus (ZIKV) attracted attention due to one striking characteristic: the ability to cross the placental barrier and infect the fetus, possibly causing severe neurodevelopmental disruptions included in the Congenital Zika Syndrome (CZS). Few years after the epidemic, the CZS incidence has begun to decline. However, how ZIKV causes a diversity of outcomes is far from being understood. This is probably driven by a chain of complex events that relies on the interaction between ZIKV and environmental and physiological variables. In this review, we address open questions that might lead to an ill-defined diagnosis of CZS. This inaccuracy underestimates a large spectrum of apparent normocephalic cases that remain underdiagnosed, comprising several subtle brain abnormalities frequently masked by a normal head circumference. Therefore, new models using neuroimaging and artificial intelligence are needed to improve our understanding of the neurobiology of ZIKV and its true impact in neurodevelopment.

Impaired Gene Expression Due to Iodine Excess in the Development and Differentiation of Endoderm and Thyroid Is Associated with Epigenetic Changes.

Background: Thyroid hormone (TH) synthesis is essential for the control of development, growth, and metabolism in vertebrates and depends on a sufficient dietary iodine intake. Importantly, both iodine deficiency and iodine excess (IE) impair TH synthesis, causing serious health problems especially during fetal/neonatal development. While it is known that IE disrupts thyroid function by inhibiting thyroid gene expression, its effects on thyroid development are less clear. Accordingly, this study sought to investigate the effects of IE during the embryonic development/differentiation of endoderm and the thyroid gland. Methods: We used the murine embryonic stem (ES) cell model of in vitro directed differentiation to assess the impact of IE on the generation of endoderm and thyroid cells. Additionally, we subjected endoderm and thyroid explants obtained during early gestation to IE and evaluated gene and protein expression of endodermal markers in both models. Results: ES cells were successfully differentiated into endoderm cells and, subsequently, into thyrocytes expressing the specific thyroid markers Tshr, Slc5a5, Tpo, and Tg. IE exposure decreased the messenger RNA (mRNA) levels of the main endoderm markers Afp, Crcx4, Foxa1, Foxa2, and Sox17 in both ES cell-derived endoderm cells and embryonic explants. Interestingly, IE also decreased the expression of the main thyroid markers in ES cell-derived thyrocytes and thyroid explants. Finally, we demonstrate that DNA methyltransferase expression was increased by exposure to IE, and this was accompanied by hypermethylation and hypoacetylation of histone H3, pointing to an association between the gene repression triggered by IE and the observed epigenetic changes. Conclusions: These data establish that IE treatment is deleterious for embryonic endoderm and thyroid gene expression.

Transcription regulators are transiently expressed during the prostate gland adaptation to the hypoandrogenic environment.

The high incidence of prostatic diseases, including malignant tumors, makes the understanding of prostate biology very important. Androgen deprivation, blockade by orchiectomy, or chemical castration causes prostate and tumor shrinkage. The gene networks involved in a cell type-specific fashion are rather unknown. This work was undertaken to identify genes with annotated function in transcription regulation that might define transitions in gene expression. A total of 15 potential regulatory genes were identified. Validation by qRT-PCR showed that Zfp703 and Arid1a exhibit expression maxima at day 1; Ash2l, Nelf, Pbx3, Eya2 at day 4; Dmrt2 at day 5 and Lbh and Sox1 at day 7 after castration. Using immunohistochemistry, we further determined that PBX3 was found in both stromal and epithelial cells, whereas ARID1A and NELF were restricted to the epithelium, and DMRT2 and EYA2 were exclusively found in the stroma. Though the proteins ZFP703 and ASH2l were not found in any experimental condition, their mRNAs were located by in situ hybridization in both epithelium and stroma. In conclusion, androgen deprivation triggers the expression of temporally regulated gene sets in both epithelial and stromal cells. These gene subsets will help establish the regulatory gene expression programs orchestrating the castration-induced remodeling of the prostate gland, and represent putative targets to increase the efficacy of androgen-deprivation to induce epithelial (and cancer) cell death.

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.