The secreted matrix protein mindin increases prostate tumor progression and tumor-bone crosstalk via ERK 1/2 regulation.

Advanced prostate cancer cells preferentially metastasize to bone by acquiring a bone phenotype that allows metastatic cells to thrive in the skeletal environment. Identification of factors that promote the expression of ectopic bone genes-process known as osteomimicry-leading to tumor progression is crucial to prevent and treat metastatic prostate cancer and prolong life expectancy for patients. Here, we identify the extracelular matrix protein mindin in the secretome of prostate adenocarcinoma cells and show that mindin overexpression in human and mouse TRAMP-C1-induced prostate tumors correlates with upregulated levels of bone-related genes in the tumorigenic prostate tissues. Moreover, mindin silencing decreased osteomimicry in adenocarcinoma cells and in the prostate tumor mice model, as well as reduced tumor cell proliferation, migration and adhesion to bone cells. Inhibition of the extracellular signal-regulated kinase 1/2 (ERK 1/2) phosphorylation decreased the proliferative, migratory and pro-adhesion actions of mindin on prostate tumor cells. In addition, conditioned media obtained by crosstalk stimulation of either osteocytes or osteoblasts with the secretome of TRAMP-C1 cells promoted osteomimicry in prostate tumor cells; an effect inhibited by mindin silencing of TRAMP-C1 cells. In vivo, tibiae of primary tumor-bearing mice overexpressed the pro-angiogenic and pro-metastattic factor vascular endothelial growth factor receptor 2 (VEGFR2) in a mindin-dependent manner. Our findings indicate that mindin is a novel regulator of osteomimicry in prostate tumors and potentially mediates tumor-bone cell crosstalk, suggesting its promising role as a target to inhibit bone metastases.

Expression of lysophosphatidic acid receptor 1 and relation with cell proliferation, apoptosis, and angiogenesis on preneoplastic changes induced by cadmium chloride in the rat ventral prostate.

BACKGROUND: Lysophosphatidic acid (LPA) is a phospholipid growth factor involved in cell proliferation, differentiation, migration, inflammation, angiogenesis, wound healing, cancer invasion, and survival. This study was directed to evaluate the immunoexpression of LPA-1, cell proliferation, apoptosis, and angiogenesis markers in preneoplastic lesions induced with cadmium chloride in rat prostate. METHODS: The following parameters were calculated in ventral prostate of normal rats and rats that received Cd in drinking water during 24 months: percentages of cells immunoreactive to LPA-1 (LILPA1), PCNA (LIPCNA), MCM7 (LIMCM7), ubiquitin (LIUBI), apoptotic cells (LIAPO), and p53 (LIp53); volume fraction of Bcl-2 (VFBcl-2); and length of microvessels per unit of volume (LVMV/mm3). Data were analyzed using Student's t-test and Pearson correlation test. RESULTS: The LILPA1 in dysplastic lesions and normal epithelium of Cd-treated rats was significantly higher than those in the control group. Markers of proliferation were significantly increased in dysplastic lesions, whereas some apoptotic markers were significantly decreased. No significant differences between groups were found in VFBcl-2. Dysplastic lesions showed a significant increase of LIp53. The length of microvessels per unit of volume was elevated in dysplastic acini. Statistically significant correlations were found only between LILPA1 and LIUBI. CONCLUSIONS: Our results suggest that LPA-1 might be implicated in dysplastic lesions induced by cadmium chloride development. More studies are needed to confirm its potential contribution to the disease.

Effect of prolactin on the population of epithelial cells from ventral prostate of intact and cyproterone acetate-treated peripubertal rats: stereological and immunohistochemical study.

The interactions between steroid and nonsteroid hormones in the prostate are of special interest during the growth phase of the gland. The purpose of this work is to study the influence of prolactin (PL), with or without androgenic blockade, on epithelial cells from peripubertal rat ventral prostate. Twenty male peripubertal Sprague-Dawley rats were grouped as controls, or treated with cyproterone acetate (CA), CA plus PL (CA-PL), or PL. The total number (N total) of epithelial cells, and their labeling indices to proliferative cell nuclear antigen (LI PCNA), apoptosis (LI apoptosis) and androgen receptors (LI AR) were measured. CA and PL treatment significantly decrease the N total, but the LI PCNA was unchanged. We have observed a greater LI apoptosis in pharmacologically castrated animals without PL than in the rats with androgenic blockade with PL. The LI AR does not change with CA treatment in the ventral region, but the PL significantly increases it. Androgenic blockade and PL decrease the number of epithelial cells from the ventral prostate. These changes are not attributable to the decrease of cell proliferation, rather to the increase of epithelial apoptosis. The increase of cells expressing AR after treatment with PL might be attributed to the decrease of testosterone secretion caused by the hyperprolactinemia. PL does not modulate the size of the ventral prostate in prepubertal rats.

Effect of prolactin and bromocriptine on the population of prostate neuroendocrine cells from intact and cyproterone acetate-treated rats: stereological and immunohistochemical study.

This work deals with the quantification of serotonin-immunoreactive prostate neuroendocrine cells (NECs) in rats exposed to prolactin in normal, cyproterone acetate-exposed, and bromocriptine-exposed animals to establish the possible influence of prolactin with or without androgenic blockade on this cell population. Thirty male peripubertal Sprague-Dawley rats were grouped as controls (CT) and those treated with cyproterone acetate (CA), cyproterone acetate plus prolactin, cyproterone acetate plus bromocriptine, prolactin (PL), and bromocriptine (BC). The volume of ductal epithelium (Vep) and total number (NSER) of the NECs serotonin-immunoreactive were measured. NECs were detected in the periurethral ducts. Compared to CT, Vep was increased in PL and BC and NSER was decreased in CA and increased in the prolactin or bromocriptine groups. The androgenic blockade decreases NSER in rat prostate; PL induces in normal and cyproterone acetate-treated rats the increase of NSER; and BC exerts a local effect over the prostate similar to that described for PL.

Immunohistochemical study of cell proliferation, Bcl-2, p53, and caspase-3 expression on preneoplastic changes induced by cadmium and zinc chloride in the ventral rat prostate.

This work was directed to evaluate immunoexpression of markers for apoptosis, resistance to apoptosis, and cell proliferation, as well as estimates of nuclear size in ventral prostate of rats treated with cadmium chloride and cadmium+zinc chloride because a possible protective effect of zinc has been postulated. The following variables were studied: volume fraction (VF) of Bcl-2 immunostaining, percentage of cells immunoreactive to proliferating cell nuclear antigen (LIPCNA) and p53 (LIp53), numerical density of caspase-3 immunoreactive cells (NV caspase-3), and estimates of volume-weighted mean nuclear volume (upsilonV). The LIPCNA and VF of Bcl-2 were significantly increased in the treated animals. The dysplasias (independent of their origin) showed a significant increase of the LIp53, NV caspase-3, and upsilonV in comparison with normal acini from treated and control animals. It can be concluded that cell proliferation is enhanced in long-term cadmium-exposed rats, and exposure to zinc combined with cadmium had no effect on any of the variables studied when comparing with normal acini. The increase of nuclear upsilonV could indicate a more aggressive behavior for pretumoral lesions.

Stereological quantification of nerve fibers immunoreactive to PGP 9.5, NPY, and VIP in rat prostate during postnatal development.

This work was undertaken to study prostate innervation during the postnatal development of rats. It deals with the quantification of nervous fibers throughout all the regions of the rat prostate during the postnatal development using a general marker for nervous tissue, protein gene product 9.5, and 2 neuropeptides (NPY and VIP). Forty male Wistar rats (prepubertals, pubertals, young, and aged adults) were studied for immunohistochemistry of protein gene product (PGP 9.5), neuropeptide Y (NPY), and vasoactive intestinal polypeptide (VIP). They were also evaluated for length density of nerve fibers (L(V) PGP 9.5, L(V) NPY, L(V) VIP). Nerve fibers immunoreactive to the 3 antigens studied were detected in all the groups and in all the prostate zones. Periductal L(V) NPY evidenced a significant increase in the pubertal group, maintained throughout adult life. Periductal L(V) VIP showed a significant increase in young adults. The length densities of VIP and NPY fibers were significantly higher in periductal and ampular locations in comparison with dorsal and ventral sites. It can be concluded that the relative amount of nerve fibers in rat prostate, detected by PGP 9.5, does not change during postnatal development. There were significant changes in NPY and VIP fibers, showing an increase in periurethral ducts at puberty. The abundance of peptidergic innervation around the excretory ducts is related to their contractility. The development of innervation of periurethral ducts is regulated by androgens.

Quantitative and immunohistochemical evaluation of PCNA, androgen receptors, apoptosis, and Glutathione-S-Transferase P1 on preneoplastic changes induced by cadmium and zinc chloride in the rat ventral prostate.

BACKGROUND: This study was directed to evaluate the immunoexpression of markers for cell proliferation, apoptosis, nuclear androgen receptors, and Glutathione-S-Transferase P1 (GSTP1), in preneoplastic changes induced by cadmium chloride (Cd) and cadmium plus zinc chloride (Cd + Zn) in rat prostate. METHODS: The following parameters were calculated in ventral prostate of normal rats and rats that received Cd or Cd + Zn in drinking water during 24 months: numerical densities of columnar, basal, and GSTP1 immunoreactive epithelial cells; percentages of cells immunoreactive to: PCNA, (LI(PCNA)), androgen receptors (LI(AR)), and of apoptotic cells. RESULTS: The LI(PCNA) was significantly increased in the animals exposed to Cd + Zn, whereas the numerical densities of both columnar (N(V) columnar cells), and GSTP1 immunoreactive (N(V) GSTP1+) cells were significantly increased in the animals treated with metals in comparison with the controls. No significant differences between the two sources of dysplasias (Cd and Cd + Zn) respecting to LI(PCNA), N(V) columnar cells, and N(V) GSTP1+ were observed. The two types of dysplasias considered together showed a significant increase for the N(V) basal, N(V) columnar, and N(V) GSTP1+ cells in comparison with normal acini of treated and controls. The percentage of apoptotic nuclei did not show significant differences among the three groups studied. CONCLUSIONS: (1) The zinc has little influence in the development of the dysplastic changes of the rat prostate mediated by cadmium. (2) The decrease of apoptosis has little influence in the development of dysplasia. (3) GSTP1 could play a role in the response to the oxidative stress in the dysplastic changes caused by cadmium.

Synthesis and biological evaluation of analogues of butyrolactone I and molecular model of its interaction with CDK2.

A series of analogues of butyrolactone I, a natural product isolated from Aspergillus terreus that selectively inhibits the CDK2 and CDK1 kinases and that has been found to exhibit an interesting antiproliferative activity, have been synthesized. Its antitumor activity has been tested. Molecular models of the complex between butyrolactone I and the CDK2 active site have been built using a combination of conformational search and automated docking techniques. The stability of the resulting complexes has been assessed by molecular dynamics simulations and the experimental results obtained for the synthesized analogues are rationalized based on the molecular models.

New analogues of amonafide and elinafide, containing aromatic heterocycles: synthesis, antitumor activity, molecular modeling, and DNA binding properties.

Amonafide- and elinafide-related mono and bisintercalators, modified by the introduction of a pi-excedent furan or thiophene ring fused to the naphthalimide moiety, have been synthesized. These compounds have shown an interesting antitumor profile. The best compound, 9, was 2.5-fold more potent than elinafide against human colon carcinoma cells (HT-29). Molecular dynamic simulations and physicochemical experiments have demonstrated that these compounds are capable of forming stable DNA complexes. These results, together with those previously reported by us for imidazo- and pyrazinonaphthalimide analogues, have prompted us to propose that the DNA binding process does not depend on the electronic nature of the fused heterocycle.

Presence of neuroendocrine cells during postnatal development in rat prostate: Immunohistochemical, molecular, and quantitative study.

BACKGROUND: This work was undertaken to study the prostate neuroendocrine cells (PNEC) during the post-natal development of rats. METHODS: Forty male Wistar rats (pre-pubertals, pubertals, young, and aged adults) were used for immunohistochemistry of chromogranin A (cgA), serotonin (SER), and protein gene product 9.5 (PGP9.5). They were also evaluated for numerical cell density (NV SER) and PNEC number per prostate (N SER). Five additional young adult rats were used for a RT-PCR study (mRNA cgA detection). RESULTS: Weak immunoreactivity to cgA was observed in pubertal rats. No PNEC immunostained to PGP 9.5 was observed. Cells expressing SER were detected in all the groups exclusively located in periurethral ducts. The NV SER increased significantly in pubertal animals. In aged animals, it decreased to levels observed in pre-pubertal rats. The N SER increased significantly from pre-pubertal to young adults, decreasing in aged adults. There was weak production of cgA mRNA, with more expression in the dorsal prostate. CONCLUSIONS: PNEC differ in rats when compared to humans: they are weakly immunopositive to cgA, do not express PGP 9.5, only show immunoreactivity to SER, and do not appear in acini. The changes in the amount of rat PNEC during the post-natal development suggest an androgenic influx. PNEC might regulate the contractility of periurethral ducts.

Synthesis, biological evaluation and DNA binding properties of novel mono and bisnaphthalimides.

A novel series of mono and bisnaphthalimides was synthesized and their antiproliferative activities were evaluated against three tumor cell lines. Bisnaphthalimides 3 and 4, bearing a pyrazine ring fused to the naphthalimide system, showed activities in the order of 10(-8) microM, similar to elinafide. DNA binding properties and the ability to induce DNA damage were studied for some of the most active compounds.