Snail knockdown reverses stemness and inhibits tumour growth in ovarian cancer.

To develop effective therapies for advanced high grade serous ovarian cancer (HGSOC), understanding mechanisms of recurrence and metastasis is necessary. In this study, we define the epithelial/mesenchymal status of cell lines that accurately model HGSOC, and evaluate the therapeutic potential of targeting Snai1 (Snail), a master regulator of the epithelial/mesenchymal transition (EMT) in vitro and in vivo. The ratio of Snail to E-cadherin (S/E index) at RNA and protein levels was correlated with mesenchymal morphology in four cell lines. The cell lines with high S/E index (OVCAR8 and COV318) showed more CSC-like, motile, and chemoresistant phenotypes than those with low S/E index (OVSAHO and Kuramochi). We tested the role of Snail in regulation of malignant phenotypes including stemness, cell motility, and chemotherapy resistance: shRNA-mediated knockdown of Snail reversed these malignant phenotypes. Interestingly, the expression of let-7 tumour suppressor miRNA was upregulated in Snail knockdown cells. Furthermore, knockdown of Snail decreased tumour burden in an orthotopic xenograft mouse model. We conclude that Snail is important in controlling HGSOC malignant phenotypes and suggest that the Snail/Let-7 axis may be an attractive target for HGSOC treatment.

[AN EXPERIMENTAL STUDY OF THE HISTOLOGICAL FIBRO GENESIS ABILITIES IN THE AREA OF IMPLANTATION OF ALOTRANSPLANTATES APPLYING INTRAABDOMINAL AND PREPERITONEAL PLASTIC SURGERY].

The histological fibro genesis abilities in the area of implantation of allotransplantates applying intraabdominal and preperitoneal plastic surgery were examined during experimental research. The experiment involved 12 Russian chinchilla rabbits. The animals were spitted into two groups: I group--operated using IPOM methodology (intraperitonealonlaymesh, n = 6) with the installation "Proceed" mesh made by "Ethicon", group II--modeling preperitoneal plastics with the installation of "Ethicon's Ultrapro" mesh (n = 6). After removing the animals from the experiment, the implants with adhering musculo-aponeurotic tissue layer were excised and sent for histological examination. At the same time the severity of the inflammatory process were rated, the composition of the inflammatory infiltrate, germination of the connective tissue through the pores of the prosthesis and neovascularization. Analyzing the research data of histological connective abilities complexes formed in the area of the allotransplants implantation using intra-abdominal and pre-peritoneal plastic during the experiment, we can conclude that intra-abdominal installation of mesh prostheses reduces the severity of inflammatory changes surrounding tissues and reduces the probability of seroma formation in comparison with the placement of the pre-peritoneal implant.

Hormone receptor expression in uterine sarcomas: prognostic and therapeutic roles.

OBJECTIVES.: The utility of hormone therapy in the management of uterine sarcomas is poorly defined. We hypothesize that estrogen receptor (ER) expression is common in uterine sarcomas, and carries prognostic significance. Further, we hypothesize that ER-positive uterine sarcomas respond to hormone therapy. METHODS.: We retrospectively reviewed charts of patients with uterine sarcomas. Stepwise Cox proportional hazards regression model was used to evaluate variables related to the risk of death: age, histology, stage, use of pelvic radiotherapy, and ER expression. In addition, we examined clinical outcomes in patients treated with aromatase inhibitors, megestrol acetate, depot medroxyprogesterone acetate, and tamoxifen. RESULTS.: Fifty-four patients underwent immunohistochemical staining, and 34 (63%) were ER-positive. Kaplan-Meier survival analysis and log-rank test indicated that patients with ER-positive sarcomas demonstrated improved overall survival when compared with ER-negative patients (median OS 36 vs. 16 months, p=0.004). Upon multivariate analysis, ER positivity retained significance as an independent predictor of survival (HR=0.32, CI 0.12-0.89, p=0.03). Four patients received hormonal treatment in the adjuvant setting and remained in remission (range of follow up: 18-68 months). Eighteen patients received hormone therapy in the setting of recurrent or progressive disease: fourteen (78%) demonstrated stable disease or complete or partial response (range of follow up: 6-124 months). CONCLUSIONS.: ER expression is common and is associated with improved overall survival in uterine sarcomas. Conducting immunohistochemical staining to ascertain ER status may aid with prognostication in this disease. Hormone therapy should be considered in patients with primary and recurrent ER-positive uterine sarcomas.

Paradoxical antagonism of PACAP receptor signaling by VIP in Xenopus oocytes via the type-C natriuretic peptide receptor.

Atrial natriuretic peptide (ANP) and the closely-related peptides BNP and CNP are highly conserved cardiovascular hormones. They bind to single transmembrane-spanning receptors, triggering receptor-intrinsic guanylyl cyclase activity. The "truncated" type-C natriuretic peptide receptor (NPR-C) has long been called a clearance receptor because it lacks the intracellular guanylyl cyclase domain, though data suggest it might negatively couple to adenylyl cyclase via G(i). Here we report the molecular cloning and characterization of the Xenopus laevis type-C natriuretic peptide receptor (XNPR-C). Analysis confirms the presence of a short intracellular C-terminus, as well as a high similarity to fish and mammalian NPR-C. Injection of XNPR-C mRNA into Xenopus oocytes resulted in expression of high affinity [(125)I]ANP binding sites that were competitively and completely displaced by natriuretic analogs and the unrelated neuropeptide vasoactive intestinal peptide (VIP). Measurement of cAMP levels in mRNA-injected oocytes revealed that XNPR-C is negatively coupled to adenylyl cyclase in a pertussis toxin-sensitive manner. When XNPR-C was co-expressed with PAC(1) receptors for pituitary adenylyl cyclase-activating polypeptide (PACAP), VIP and natriuretic peptides counteracted the cAMP induction by PACAP. These results suggest that VIP and natriuretic peptides can potentially modulate the action of PACAP in cells where these receptors are co-expressed.

Proliferative actions of natriuretic peptides on neuroblastoma cells. Involvement of guanylyl cyclase and non-guanylyl cyclase pathways.

To identify neural tumor cell lines that could be used as models to study growth-related natriuretic peptide actions, we determined the effects of these peptides on the proliferation of human and rodent neuroblastoma cell lines. Subnanomolar concentrations of atrial natriuretic peptide (ANP) and type C natriuretic peptide (CNP) stimulated proliferation in all four cell lines. These actions were associated with cGMP elevation and were blocked by a protein kinase G inhibitor. These data imply the involvement of guanylyl cyclase (GC)-coupled natriuretic receptors. However, higher concentrations of ANP and CNP, and low concentrations of des-[Gln(18),Ser(19),Gly(20),Leu(21),Gly(22)]-ANP(4-23)-NH(2) (desANP(4-23)) (analog for NPR-C receptor) exerted antiproliferative actions in three of the cell lines. These effects were insensitive to a protein kinase G inhibitor and to HS-142-1, suggesting that growth-inhibitory actions involved a non-GC receptor. They did not appear to involve cAMP, protein kinase A, protein kinase C, or calcium mobilization but were abolished when constitutive mitogen-activated protein kinase activity was inhibited. Radioligand binding experiments revealed the presence of a uniform class of binding sites in NG108 cells and multiple binding sites in Neuro2a cells. Northern and reverse transcriptase-polymerase chain reaction analyses revealed differential gene expression for NPR-A/B/C in NG108 and Neuro2a cells. The results indicate that natriuretic peptides stimulate neuroblastoma cell proliferation through type NPR-A/B (GC) receptors. Higher concentrations of ANP and CNP exerted a mitogen-activated protein kinase-dependent antiproliferative action mediated by a non-GC receptor that interacts with desANP(4-23) with relatively high affinity.

Pituitary adenylyl cyclase-activating polypeptide stimulates DNA synthesis but delays maturation of oligodendrocyte progenitors.

The neuropeptide pituitary adenylyl cyclase-activating peptide (PACAP) and one of its receptors (PAC(1)) are expressed in embryonic neural tube, where they appear to regulate neurogenesis and patterning. We now show that PAC(1) gene expression is also present in neonatal rats in the ventricular and subventricular zones and in the optic chiasm, areas that are rich in oligodendrocyte (OL) progenitors (OLP). Because actions of PACAP on OLP have not been reported, we examined the effects of PACAP on the proliferation of purified OLP in culture and on myelinogenesis in cerebellar slices. Northern analyses on total RNA from purified glial cell subtypes revealed an abundant 7 kb hybridizing transcript in OLP, which was confirmed to correspond to the PAC(1) receptor by reverse transcription-PCR. The presence of this receptor was also corroborated by radioligand binding and cAMP assay. In cultured OL, receptor density decreased during maturation but was partially counterbalanced by the appearance of sites that bound both PACAP and the related peptide vasoactive intestinal peptide. PACAP increased DNA synthesis in OLP cultures almost twofold and increased the bromodeoxyuridine-labeling index in O4-positive OLP. PACAP treatment also resulted in decreased sulfate incorporation into sulfatide in cultures of differentiating OL. The PACAP effect on sulfatide synthesis was fully reproduced in a cerebellar explant model. These findings indicate that PACAP may act at two stages during OL development to (1) stimulate proliferation and (2) delay maturation and/or myelinogenesis.