Proteomic and Phosphoproteomic Reprogramming in Epithelial Ovarian Cancer Metastasis.

Epithelial ovarian cancer (EOC) is a high-risk cancer presenting with heterogeneous tumors. The high incidence of EOC metastasis from primary tumors to nearby tissues and organs is a major driver of EOC lethality. We used cellular models of spheroid formation and readherence to investigate cellular signaling dynamics in each step toward EOC metastasis. In our system, adherent cells model primary tumors, spheroid formation represents the initiation of metastatic spread, and readherent spheroid cells represent secondary tumors. Proteomic and phosphoproteomic analyses show that spheroid cells are hypoxic and show markers for cell cycle arrest. Aurora kinase B abundance and downstream substrate phosphorylation are significantly reduced in spheroids and readherent cells, explaining their cell cycle arrest phenotype. The proteome of readherent cells is most similar to spheroids, yet greater changes in the phosphoproteome show that spheroid cells stimulate Rho-associated kinase 1 (ROCK1)-mediated signaling, which controls cytoskeletal organization. In spheroids, we found significant phosphorylation of ROCK1 substrates that were reduced in both adherent and readherent cells. Application of the ROCK1-specific inhibitor Y-27632 to spheroids increased the rate of readherence and altered spheroid density. The data suggest ROCK1 inhibition increases EOC metastatic potential. We identified novel pathways controlled by Aurora kinase B and ROCK1 as major drivers of metastatic behavior in EOC cells. Our data show that phosphoproteomic reprogramming precedes proteomic changes that characterize spheroid readherence in EOC metastasis.

Materials for restoration of primary teeth: 2. Glass ionomer derivatives and compomers.

A wide variety of materials have been used for the restoration of primary teeth. Resin-modified glass ionomers and the more recently introduced viscous glass ionomers have been developed from conventional glass ionomer materials in an attempt to overcome the suboptimal properties of conventional glass ionomers. These materials would appear to have the necessary physical characteristics for restorations in load-bearing situations in primary teeth, as have the resin-based compomer materials, which now have well documented success rates in a number of studies. The first of these two articles described 'traditional' restorative materials, including amalgam and conventional glass ionomer, for the restoration of primary teeth. This paper describes materials derived from traditional glass ionomers in an attempt to overcome the suboptimal properties of conventional glass ionomers and resin-based materials such as compomer.

Materials for restoration of primary teeth: I. Conventional materials and early glass ionomers.

This paper demonstrates how the treatment of primary dentition may present the clinician with increased difficulties compared with the preparation and placement of restorations in adult dentition. Established dental materials (dental amalgam and conventional glass ionomer cements) and less well established alternative materials (copper cements) are reviewed. The use of amalgam to restore primary dentition is the subject of concern amongst the dental profession in terms of lack of adhesion and potential toxicity concerns, while the low tensile strength of traditional glass ionomer cements make them less suitable for the restoration of primary dentition.

Seasonal changes in plasma sex steroid levels in the male tuatara, Sphenodon punctatus, from Stephens Island, New Zealand.

A unique opportunity, occasioned by the sacrifice of five male tuataras (Sphenodon punctatus), was taken to measure the circulating levels of a number of sex steroids, and other parameters, at different seasons throughout the year on Stephens Island, New Zealand. Male tuataras exhibit continuous spermatocytogenesis throughout the year (H. Saint Girons and D. G. Newman, 1987, N.Z.J.Zool. 14,231-237) but levels of sex steroids showed significant seasonal variation nonetheless, with testosterone concentrations being positively correlated with the height of the epithelium lining the epididymal ducts. Plasma testosterone and 5 alpha-dihydrotestosterone levels were highest in February, coincident with the mating season when spermiogenesis is maximal and epididymal ducts are hypertrophied, but DHT concentrations were generally lower and more constant throughout the year. Circulating levels of progesterone, 17 beta-oestradiol, and corticosterone showed no significant changes over the period of sampling which extended from February until August. The tuatara is the only surviving member of the ancient Sub-Order Rhynchocephalia, and it seems likely that testosterone functions as a male sex hormone in this species, as it does in other members of the Class Reptilia.

Determination of 18O by prompt nuclear reaction analysis: application for measurement of microsamples.

A method is described for the routine determination of 18O concentrations in microsamples of biological fluids. The method utilizes the prompt nuclear reaction 18O(p, alpha o)15N, and 846-keV protons from a 3-MeV Van de Graaff Accelerator are focused on approximately 2,000-A-thick Ta2O5 targets prepared by anodic oxidation from 50-microliter samples of water distilled from blood or other biological fluids. The broad cross section of the resonance peak for this nuclear reaction (47 keV) ensures high yields, especially at small reaction angles, and the high-energy alpha particles produced by the reaction (4 MeV) are readily separated from scattered protons by the use of an aluminized Mylar foil of suitable thickness. Background levels of 18O (0.204 atom%) can be detected with run times of approximately 5-8 min, and the sensitivity of the method is of the order of 0.05 atom %. Experimental error due to sample preparation was found to be 1.7%, and counting errors were close to theoretical limits so that total error was of the order of 2.5%. Duplicate samples were analyzed by use of the 18O(p, alpha o)15N reaction at Lucas Heights, Australia, and the 18O(p,n)18F reaction by the method of Wood et al. (Anal. Chem. 47: 646-650, 1975) at the University of California, Los Angeles, and the agreement was excellent (y = 1.0123x - 0.0123, r = 0.991, P less than 0.001). The theoretical limitations and the general applicability of the method in biological studies designed to estimate the rate of metabolism of free-ranging animals are discussed.

Characterization and properties of a progesterone receptor in the uterus of the quokka (Setonix brachyurus).

A progesterone receptor system, with a high specificity for progestins, was detected in the uterine tissue of the marsupial, Setonix brachyurus (quokka), using the synthetic progestin 17 alpha, 21-dimethyl-19-nor-4,9-pregnadiene-3,20-dione (R5020). The apparent equilibrium dissociation constant of the ligand binding to the cytosolic component was 2.2 nmol/l, and to the nuclear component 4.8 nmol/l. Significant loss of binding ability of the receptor occurred when cytosol was pretreated with dextran-coated charcoal. All binding studies were performed, therefore, in the presence of endogenous steroid which was demonstrated to affect the dissociation constant but have no effect on the estimation of the concentration of binding sites. Cytosolic binding was increased sixfold by oestradiol-17 beta treatment in vivo, and the translocation of the bound complex into the nucleus was effected by progesterone. It is suggested that the binding component described plays a role in the action of progesterone on the uterine tissue of the quokka.

Difference in concentration of progesterone in plasma between pregnant and non-pregnant quokkas (Setonix brachyurus).

The plasma progesterone concentrations during pregnancy and the oestrous cycle of the quokka were measured daily after each had been initiated by the removal of pouch young. Progesterone levels ranged from 0.6 ng/ml in the early stages of the oestrous cycle to about 2.5 ng/ml at the peak of the luteal phase. There was no significant difference between pregnant and non-pregnant states before the removal of the pouch young nor in the latter half of the cycle. However, the plasma progesterone concentration on days 3--4 after removal of the pouch young was significantly greater in pregnant animals when compared with non-pregnant animals at the same stage and also when compared with the levels before removal of young. This early peak in the concentration of progesterone in peripheral plasma is discussed in relation to the development of the previously dormant blastocyst.