Induction of more aggressive tumoral phenotypes in LNCaP and PC3 cells by serum exosomes from prostate cancer patients.

Prostate cancer (PCa) is the second most frequent and sixth most fatal cancer in men worldwide. Despite its high prevalence, our understanding of its etiology and the molecular mechanisms involved in the progression of the disease is substantially limited. In recent years, the potential participation of exosomes in this process has been suggested. Therefore, we aim to study the effect of exosomes isolated from the serum of patients with PCa on various cellular processes associated with increased tumor aggressiveness in two PCa cell lines: LNCaP-FGC and PC3. The exosomes were isolated by filtration wand ultracentrifugation. Their presence was confirmed by immunodetection of specific markers and their size distribution was analyzed by Dynamic Light Scattering (DLS). The results obtained demonstrated that serum exosomes from PCa patients increased migration of PC3 cells and neuroendocrine differentiation of LNCaP-FGC cells regardless of the grade of the tumor. PCa serum exosomes also enhanced the secretion of enzymes related to invasiveness and resistance to chemotherapeutics, such as extracellular matrix metalloproteases 2 and 9, and gamma-glutamyltransferase in both cell lines. Altogether, these findings support the pivotal participation of exosomes released by tumoral cells in the progression of PCa. Future studies on the molecular mechanisms involved in the observed changes could provide crucial information on this disease and help in the discovery of new therapeutic targets.

Anti-proliferative and pro-apoptotic effects of GHRH antagonists in prostate cancer.

Growth hormone-releasing hormone (GHRH) and its receptors have been implicated in the progression of various tumors. In vitro and in vivo studies have demonstrated that GHRH antagonists inhibit the growth of several cancers. GHRH antagonists, JMR-132 and JV-1-38 inhibit the growth of androgen-independent prostate tumors. Here we investigated the involvement of GHRH antagonists in proliferative and apoptotic processes. We used non-tumoral RWPE-1 and tumoral LNCaP and PC3 human prostatic epithelial cells, as well as an experimental model of human tumor PC3 cells. We evaluated the effects of JMR-132 and JV-1-38 antagonists on cell viability and proliferation in the three cell lines by means of MTT and BrdU assays, respectively, as well as on cell cycle and apoptotic process in PC3 cells. The expression levels of PCNA, p53, p21, CD44, Cyclin D1, c-myc, Bax and Bcl2 were determined in both in vivo and in vitro models by means of Western-blot and RT-PCR. GHRH antagonists suppressed cell proliferation and decreased the levels of the proliferation marker, PCNA, in the three cell lines and in PC3 tumor. GHRH antagonists led to an increase of cells in S-phase and a decrease in G1 and G2/M phases, and induced S-phase arrest and increase of apoptotic cells. The effects of GHRH-antagonists on cell cycle could be due to the changes observed in the expression of p21, p53, Bax, Bcl2, CD44, Cyclin D1, c-myc and caspase 3. Present results confirm and extend the role of GHRH antagonists as anti-proliferative and pro-apoptotic molecules in prostate cancer.

El bisfenol A: un factor ambiental implicado en el daño nefrovascular / Bisphenol A: An environmental factor implicated in renal vascular damage

No disponible

Oral administration of bisphenol A induces high blood pressure through angiotensin II/CaMKII-dependent uncoupling of eNOS.

Bisphenol A (BPA) is found in human urine and fat tissue. Higher urinary BPA concentrations are associated with arterial hypertension. To shed light on the underlying mechanism, we orally administered BPA (4 nM to 400 µM in drinking water) to 8-wk-old CD11 mice over 30 d. Mice developed dosage-dependent high blood pressure (systolic 130 ± 12 vs. 170 ± 12 mmHg; EC50 0.4 µM), impairment of acetylcholine (AcH)-induced carotid relaxation (0.66 ± 0.08 vs. 0.44 ± 0.1 mm), a 1.7-fold increase in arterial angiotensin II (AngII), an 8.7-fold increase in eNOS mRNA and protein, and significant eNOS-dependent superoxide and peroxynitrite accumulation. AngII inhibition with 0.5 mg/ml losartan reduced oxidative stress and normalized blood pressure and endothelium-dependent relaxation, which suggests that AngII uncouples eNOS and contributes to the BPA-induced endothelial dysfunction by promoting oxidative and nitrosative stress. Microarray analysis of mouse aortic endothelial cells revealed a 2.5-fold increase in expression of calcium/calmodulin-dependent protein kinase II-α (CaMKII-α) in response to 10 nM BPA, with increased expression of phosphorylated-CaMKII-α in carotid rings of BPA-exposed mice, whereas CaMKII-α inhibition with 100 nM autocamptide-2-related inhibitor peptide (AIP) reduced BPA-mediated increase of superoxide. Administration of CaMKII-α inhibitor KN 93 reduced BPA-induced blood pressure and carotid blood velocity in mice, and reverted BPA-mediated carotid constriction in response to treatment with AcH. Given that CaMKII-α inhibition prevents BPA-mediated high blood pressure, our data suggest that BPA regulates blood pressure by inducing AngII/CaMKII-α uncoupling of eNOS.

Bisphenol-A induces podocytopathy with proteinuria in mice.

Bisphenol-A, a chemical used in the production of the plastic lining of food and beverage containers, can be found in significant levels in human fluids. Recently, bisphenol-A has been associated with low-grade albuminuria in adults as well as in children. Since glomerular epithelial cells (podocytes) are commonly affected in proteinuric conditions, herein we explored the effects of bisphenol-A on podocytes in vitro and in vivo. On cultured podocytes we first observed that bisphenol-A-at low or high concentrations-(10 nM and 100 nM, respectively) was able to induce hypertrophy, diminish viability, and promote apoptosis. We also found an increase in the protein expression of TGF-ß1 and its receptor, the cyclin-dependent kinase inhibitor p27Kip1, as well as collagen-IV, while observing a diminished expression of the slit diaphragm proteins nephrin and podocin. Furthermore, mice intraperitoneally injected with bisphenol-A (50 mg/Kg for 5 weeks) displayed an increase in urinary albumin excretion and endogenous creatinine clearance. Renal histology showed mesangial expansion. At ultrastructural level, podocytes displayed an enlargement of both cytoplasm and foot processes as well as the presence of condensed chromatin, suggesting apoptosis. Furthermore, immunohistochemistry for WT-1 (specific podocyte marker) and the TUNEL technique showed podocytopenia as well as the presence of apoptosis, respectively. In conclusion, our data demonstrate that Bisphenol-A exposure promotes a podocytopathy with proteinuria, glomerular hyperfiltration and podocytopenia. Further studies are needed to clarify the potential role of bisphenol-A in the pathogenesis as well as in the progression of renal diseases.

Novel role of parathyroid hormone-related protein in the pathophysiology of the diabetic kidney: evidence from experimental and human diabetic nephropathy.

Parathyroid hormone-related protein (PTHrP) and its receptor type 1 (PTH1R) are extensively expressed in the kidney, where they are able to modulate renal function. Renal PTHrP is known to be overexpressed in acute renal injury. Recently, we hypothesized that PTHrP involvement in the mechanisms of renal injury might not be limited to conditions with predominant damage of the renal tubulointerstitium and might be extended to glomerular diseases, such as diabetic nephropathy (DN). In experimental DN, the overexpression of both PTHrP and the PTH1R contributes to the development of renal hypertrophy as well as proteinuria. More recent data have shown, for the first time, that PTHrP is upregulated in the kidney from patients with DN. Collectively, animal and human studies have shown that PTHrP acts as an important mediator of diabetic renal cell hypertrophy by a mechanism which involves the modulation of cell cycle regulatory proteins and TGF- ß 1. Furthermore, angiotensin II (Ang II), a critical factor in the progression of renal injury, appears to be responsible for PTHrP upregulation in these conditions. These findings provide novel insights into the well-known protective effects of Ang II antagonists in renal diseases, paving the way for new therapeutic approaches.

Parathyroid hormone-related protein is a hypertrophy factor for human mesangial cells: Implications for diabetic nephropathy.

Hypertrophy of human mesangial cells (HMC) is among the earliest characteristics in patients with diabetic nephropathy (DN). Recently, we observed the upregulation of parathyroid hormone (PTH)-related protein (PTHrP) in experimental DN, associated with renal hypertrophy. Herein, we first examined whether PTHrP was overexpressed in human DN, and next assessed the putative role of this protein on high glucose (HG)-induced HMC hypertrophy. As previously found in mice, kidneys from diabetic patients showed an increased tubular and glomerular immunostaining for PTHrP. In HMC, HG medium increased PTHrP protein expression associated with the development of hypertrophy as assessed by cell protein content. This effect was also induced by PTHrP(1-36). HG and PTHrP(1-36)-induced hypertrophy were associated with an increase in cyclin D1 and p27Kip1 protein expression, a decreased cyclin E expression, and the prevention of cyclin E/cdk2 complex activation. Both PTHrP neutralizing antiserum (α-PTHrP) and the PTH/PTHrP receptor antagonist (JB4250) were able to abolish HG induction of hypertrophy, the aforementioned changes in cell cycle proteins, and also TGF-ß1 up-regulation. Moreover, the capability of both HG and PTHrP(1-36) to induce HMC hypertrophy was abolished by α-TGFß1. These data show for the first time that PTHrP is upregulated in the kidney of patients with DN. Our findings also demonstrate that PTHrP acts as an important mediator of HG-induced HMC hypertrophy by modulating cell cycle regulatory proteins and TGF-ß1.

Hormone-sensitive lipase expression and IHC localization in the rat ovary, oviduct, and uterus.

Hormone-sensitive lipase (HSL) is a key regulator of cholesterol esters metabolism. The aim of this study was to determine HSL localization in rat female reproductive organs during the ovarian cycle by IHC methods. HSL was located in the ovarian epithelium. The granulosa cells and oocytes of primordial follicles were immunonegative. In mature follicles, HSL was found in oocytes and theca and granulosa cells. However, HSL expression in theca cells and oocytes decreased during follicular atresia. Luteal cells showed HSL staining in cytoplasm during proestrus and estrus, in the nucleus during metestrus, and in cytoplasm and the nucleus during diestrus. In the tubaric ampulla, HSL was located in the epithelial cells nuclei and in the cilia during proestrus and estrus but mainly in the nucleus during metestrus and diestrus. In the isthmus, cells showed HSL immunolabeling in the nucleus and cilia during proestrus, but only in the cilia during estrus, metestrus, and diestrus. In the uterus, HSL was found in the epithelial cells nuclei. HSL-immunoreactive bands at 84, 67, 54, and 43 kDa were found in rat female reproductive organs. HSL labeling in the nucleus of epithelial and germ cells suggests an as yet unknown function for this protein, probably related to oogenesis and cell proliferation.

PCPH/ENTPD5 expression enhances the invasiveness of human prostate cancer cells by a protein kinase C delta-dependent mechanism.

Previous reports showed that PCPH is mutated or deregulated in some human tumors, suggesting its participation in malignant progression. Immunohistochemical analyses showed that PCPH is not expressed in normal prostate, but its expression increases along cancer progression stages, being detectable in benign prostatic hyperplasia, highly expressed in prostatic intraepithelial neoplasia, and remaining at high levels in prostate carcinoma. Experiments designed to investigate the contribution of PCPH to the malignant phenotype of prostate cancer cells showed that PCPH overexpression in PC-3 cells, which express nearly undetectable PCPH levels, increased collagen I expression and enhanced invasiveness, whereas shRNA-mediated PCPH knockdown in LNCaP cells, which express high PCPH levels, down-regulated collagen I expression and decreased invasiveness. PCPH regulated invasiveness and collagen I expression by a mechanism involving protein kinase C delta (PKC delta): (a) PCPH knockdown in LNCaP cells decreased PKC delta levels relative to control cells; (b) PKC delta knockdown in LNCaP cells recapitulated all changes caused by PCPH knockdown; and (c) forced expression of PKC delta in cells with knocked down PCPH reverted all changes provoked by PCPH down-regulation and rescued the original phenotype of LNCaP cells. These results strongly suggested that the expression level and/or mutational status of PCPH contributes to determine the invasiveness of prostate cancer cells through a mechanism involving PKC delta. Data from immunohistochemical analyses in serial sections of normal, premalignant, and malignant prostate specimens underscored the clinical significance of our findings by showing remarkably similar patterns of expression for PCPH and PKC delta, thus strongly suggesting their likely coregulation in human tumors.

The antidepressant imipramine inhibits M current by activating a phosphatidylinositol 4,5-bisphosphate (PIP2)-dependent pathway in rat sympathetic neurones.

Little is known about the intracellular actions of imipramine (IMI) in the regulation of ion channels. We tested the action of IMI on the intracellular cascade that regulates M current (I(M)) in superior cervical ganglion neurones (SCGs). Dialysis of the cells with GDPbetaS, a G protein signaling blocker, did not disrupt the inhibition of I(M). When we incubated the cells with the phospholipase C (PLC) inhibitor U73122, it prevented the I(M) inhibition by IMI. Also, when we dialyzed the cells with an intracellular Ca2+ chelator, it did not disrupt I(M) inhibition by IMI, as occurs in the M1 cascade. When we incubated the cells with the generic kinase inhibitor wortmannin, it prevented the recovery of I(M) from the inhibition by IMI. Also, when we applied phosphatidylinositol 4,5-bisphosphate (PIP2) intracellularly, it diminished the inhibition of I(M) by IMI. Our findings suggest that PLC is the target for IMI, that recovery of I(M) needs lipid phosphorylation for PIP2 resynthesis, and that IMI inhibits I(M) by activating a PLC-dependent pathway, likely by decreasing the concentration of PIP2.

Deregulated expression of the PCPH proto-oncogene in human breast cancers.

We performed a study on the expression of the PCPH protein in samples corresponding to normal, pre-malignant and malignant stages of the human mammary gland by using protocols of immunohistochemistry and Western blot analysis with anti-PCPH specific antibodies. Results obtained from the immunohistochemical study showed that PCPH was undetectable in samples of normal breast and of benign diseases, with the exception of glands presenting apocrine metaplasia, in which an intense PCPH stain was observed both in the basal cytoplasm of the secretory cells and in the apocrine secretion. On the contrary, an intense labeling was observed in the cytoplasm of neoplastic cells in samples of both ductal and lobular carcinoma in situ, with this immunostaining increasing even further in samples of infiltrating carcinoma, both ductal and lobular. Western blot analyses of the same set of samples detected a 47 kDa form as the main PCPH polypeptide present in all cases studied. However, whereas this 47 kDa polypeptide was the only PCPH form detected in normal and pre-malignant samples, multiple forms could be detected in carcinoma samples, indicating the presence of altered PCPH polypeptides at these disease stages. These results were in agreement with those from the immunohistochemical study and together indicated that PCPH protein expression represents a good molecular marker to follow the process of human breast carcinogenesis. Furthermore, these results suggested that characterization of the pattern and level of PCPH expression may be a useful tool for early identification of breast cancers.

Cloning, expression, and regulation by androgens of a putative member of the oxytocinase family of proteins in the rat prostate.

BACKGROUND: Proteases are relevant in the physiology of the prostate, and its expression is regulated by androgens. METHODS: Isolation of a novel cDNA from the rat prostate was done by reverse transcriptase-polymerase chain reaction and rapid amplification of cDNA ends. By Northern blot, we analyzed the RNA expression in different tissues and in the prostate after orchidectomy and androgen treatment. By using in situ hybridization, we studied the cellular localization of the RNA. RESULTS: The cDNA codes a putative novel form of the vp-165 aminopeptidase family of proteins that we named short-vp. The short-vp probe labels one mRNA of 1.3 kb in the prostate, brain, testis, heart, and kidney. In the prostate, the levels of short-vp mRNA decrease after orchidectomy and increase with testosterone treatment. The short-vp mRNA is expressed by the prostatic epithelial cells. CONCLUSION: We isolated one putative member of the oxytocinase family of proteins that is expressed in various tissues and by the epithelial cells of the prostate. The expression of short-vp mRNA in the prostate depends on androgen levels.

Regulation of proliferation/apoptosis equilibrium by mitogen-activated protein kinases in normal, hyperplastic, and carcinomatous human prostate.

This study investigate the expression of the mitogen-activated protein kinases (MAPKs) in normal prostate, benign prostatic hyperplasia (BPH), and prostatic cancer (PC), and also the possible relationship between the activity of these MAPKs and the apoptosis/proliferation index. Immunochemical techniques were carried out using 2 mouse monoclonal antibodies against human extracellular signal-regulated protein kinase (ERK) and Jun N-terminal kinase (JNK), and 1 goat polyclonal antibody against mouse p38. To compare the results obtained in the 3 specimens, the average percentages of both epithelial and stromal immunostained cells were calculated on immunostained sections. For each of the 3 kinases studied, the percentage of immunostained stromal cells did not change with prostatic alterations. For both ERK and p38, the percentage of immunostained epithelial cells increased significantly in BPH and even more so in PC. For JNK, the percentage of immunostained epithelial cells increased significantly only in PC. These results suggest that ERK could be involved in the elevated proliferation indexes reported in BPH and PC, whereas p38 might contribute to the increased apoptotic index reported in PC. The most probable action of JNK in PC would be cell proliferation stimulation. Overexpression of MAPKs, involved in the development of prostatic hyperplasia and neoplasia, might be secondary to the overexpression of several growth factors.