Selective antagonism of the prostaglandin F2α receptor does not cause constriction of the ductus arteriosus in fetal rats

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Abstracts / Toxicology Letters 258S (2016) S62–S324

same NRTIs. Protein expression of Lon, SIRT3, heat shock protein (HSP) 60, phospho-eukaryotic translation initiation factor 2␣ (p-eIF2␣; Ser51) and phospho-c-jun N-terminal kinase (pJNK; Thr183/Tyr185) were quantified by western blots. The data showed all stress responses were significantly increased in HepG2 cells by all antiretroviral drugs at 24 h (p < 0.0001); however, at 120 h, a significant depletion in the ATP-dependent proteins Lon (p = 0.00013) and HSP60 (p < 0.0001) was observed. Proteins initiated by endoplasmic reticulum stress: p-eIF2␣ (p = 0.001) and p-JNK (p = 0.0029), were significantly reduced following prolonged treatment. SIRT3 was maintained at elevated levels in the treated cells following prolonged exposure (p < 0.001). We conclude that the ATP dependent proteins are more relevant to acute toxicity, while SIRT3 confers protection over prolonged periods of toxicity. http://dx.doi.org/10.1016/j.toxlet.2016.06.1525 P06-033 Selective antagonism of the prostaglandin F2␣ receptor does not cause constriction of the ductus arteriosus in fetal rats O. Pohl 1,∗ , F. Spézia 2 , F. Gervais 2 , P. Bennett 3 , A. Chollet 1 , E. Loumaye 1 1

ObsEva SA, Plan-les-Ouates, Switzerland CiToxLAB, Evreux, France 3 Institute for Reproductive and Developmental Biology, Imperial College, London, United Kingdom 2

Prostaglandins play an essential role in term and preterm labor. Tocolysis with non-steroidal anti-inflammatory drugs (NSAID), which inhibit prostaglandin synthesis, is an effective treatment for preterm labor (PTL). However, the use of NSAIDs is limited to 48 h and complicated by in-utero constriction of the ductus arteriosus (DA). OBE002 is a new, orally-active, selective prostaglandin F2␣ (PGF2␣) receptor antagonist which is being developed to delay PTL. To clarify the potential of OBE002 to constrict the DA, we administered vehicle, OBE002 or the NSAID indomethacin to near-term rats on gestation day 21. Four hours after treatment cesarean section was performed, neonates were euthanized and direct examination of the DA was performed. Constriction of the DA was graded from “no constriction (0)” to “DA fully constricted (3)”. OBE002 (20 mg/kg) or vehicle (PEG400), administered intravenously to the rat, did not constrict the fetal DA, whereas indomethacin treated rats had constricted DA; mean grades were 0.03 ± 0.18, 0.00 ± 0.00 and 0.83 ± 0.19, respectively. These results indicate that the PGF2␣ receptor does not play a major role in the constriction of the fetal DA and show that PGF2␣ antagonists such as OBE002 may be devoid of the safety limitations of NSAIDs for the treatment of PTL. http://dx.doi.org/10.1016/j.toxlet.2016.06.1526

P06-034 Determination of telomerase activity and associated TERT, PTEN protein expressions in stanozolol exposed rat liver E. Ozcagli 1,∗ , M. Kara 1 , T. Kotil 2 , B. Alpertunga 1 1

Department of Pharmaceutical Toxicology, Faculty of Pharmacy, Istanbul University, Istanbul, Turkey 2 Department of Histology and Embryology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey Stanozolol is an anabolic androgenic steroid (AAS), structurally 17␣-alkylated derivatives of testosterone. Stanozolol is commonly misused to improve muscle strength and athletic performance and it has a widespread usage among athletes and teenagers. Stanozolol misuse has been associated with several adverse effects on immune, cardiovascular, sebaceous, endocrine and urogenital system. Stanozolol misuse has been also associated with several cancers including hepatocellular adenomas. Telomerase plays an important role in the mechanism of cellular aging and tumorogenesis. Telomerase activity is also an important molecular factor for hepatocellular carcinoma mechanism. Telomerase associated PTEN and TERT proteins work on the opposite expression pattern. The purpose of this study was to investigate stanozolol’s effects on telomerase activity and PTEN, TERT expression profile at the supraphysiological doses in Sprague-Dawley male rats. 34 male rats were divided into 5 groups as I-control (n = 5), II-solvent control (n = 5), III-stanozolol (n = 8), IV-solvent control-exercise (n = 8) and V-stanozolol-exercise (n = 8). Also expression levels of telomerase associated TERT and PTEN proteins were assessed and immunohistochemical determination was performed. According to our preliminary results, TERT gene expression was increased in Group III and PTEN gene expression was increased in Group V compared to controls (Group I). Our results demonstrated preventive role of exercise in stanozolol misuse. These results are in line with telomerase activity and immunohistochemical analysis. http://dx.doi.org/10.1016/j.toxlet.2016.06.1527 P06-035 3D hepatic spheroid models for the detection and study of compounds with cholestatic liability D.F. Hendriks 1 , L. Fredriksson Puigvert 1 , S. Messner 2,∗ , W. Moritz 2 , M. Ingelman Sundberg 1

1

Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden 2 InSphero AG, Schlieren, Canton of Zürich, Switzerland Drug-induced cholestasis is clinically important and causes withdrawal of drugs in development. At present the screening for potentially cholestatic drugs is restricted to the ability of the drug candidate to inhibit the bile salt export pump (BSEP). Three different 3D hepatic spheroid models, 2 consisting of primary human hepatocytes (PHH) and one with HepaRG cells, were shown to preserve a highly differentiated phenotype for 5 weeks of culture. Here, we evaluated whether these models could be useful for identification of cholestatic drugs. By repeatedly co-exposing both spheroid models for 8 days we observed selective synergistic toxicity between compounds known to cause cholestasis in vivo in man and a non-toxic human bile acid mix (BAs), whereas no such synergism was observed using the non-cholestatic hepatotoxicants. The synergistic toxic interaction intensified in both PHH and Hep-