BackgroundJaagsiekte sheep retrovirus (JSRV) is the causative agent of ovine pulmonary adenocarcinoma (OPA), a transmissible neoplastic disease of sheep. OPA is an economically important veterinary disease and is also a valuable naturally occurring animal model of human lung cancer, with which it shares a similar histological appearance and the activation of common cell signaling pathways. Interestingly, the JSRV Env protein is directly oncogenic and capable of driving cellular transformation in vivo and in vitro. Previous studies of JSRV infection in cell culture have been hindered by the lack of a permissive cell line for the virus. Here, we investigated the ability of JSRV to infect slices of ovine lung tissue cultured ex vivo.ResultsWe describe the use of precision cut lung slices from healthy sheep to study JSRV infection and transformation ex vivo. Following optimization of the culture system we characterized JSRV infection of lung slices and compared the phenotype of infected cells to natural field cases and to experimentally-induced OPA tumors from sheep. JSRV was able to infect cells within lung slices, to produce new infectious virions and induce cell proliferation. Immunohistochemical labeling revealed that infected lung slice cells express markers of type II pneumocytes and phosphorylated Akt and ERK1/2. These features closely resemble the phenotype of natural and experimentally-derived OPA in sheep, indicating that lung slice culture provides an authentic ex vivo model of OPA.ConclusionsWe conclude that we have established an ex vivo model of JSRV infection. This model will be valuable for future studies of JSRV replication and early events in oncogenesis and provides a novel platform for studies of JSRV-induced lung cancer.

Objective: Acute mouse models of inflammatory bowel disease (IBD) fail to mirror the chronic nature of IBD in patients. We sought to develop a chronic mouse IBD model for assessing long-term anti-inflammatory effects with ultrasound molecular imaging (USMI) by using dual P- and E-selectin targeted microbubbles (MBSelectin).Materials and Methods: Interleukin 10 deficient (IL-10-/- on a C57BL/6 genetic background; n=55) and FVB (n=16) mice were used. In IL-10-/-mice, various experimental regimens including piroxicam, 2,4,6-trinitrobenzenesulfonic acid (TNBS) or dextran sulfate sodium (DSS), respectively were used for promoting colitis; colitis was induced with DSS in FVB mice. Using clinical and small animal ultrasound scanners, evolution of inflammation in proximal, middle and distal colon, was monitored with USMI by using MBSelectin at multiple time points. Imaged colon segments were analyzed ex vivo for inflammatory changes on H&E staining and for P-selectin expression on immunofluorescence staining.Results: Sustained colitis was not detected with USMI in IL-10-/- or FVB mice with various experimental regimens. USMI signals either gradually decreased after the colitis enhancing/inducing drug/agents were discontinued, or the mortality rate of mice was high. Inflammation was observed on H&E staining in IL-10-/- mice with piroxicam promotion, while stable overexpression of P-selectin was not found on immunofluorescence staining in the same mice.Conclusion: Sustained colitis in IL-10-/- mice induced with piroxicam, TNBS or DSS, and in FVB mice induced with DSS, was not detected with USMI using MBSelectin, and this was verified by immunofluorescence staining for inflammation marker P-selectin. Thus, these models may not be appropriate for long-term monitoring of chronic colitis and subsequent treatment response with dual-selectin targeted USMI.

An 11-year-old, spayed female domestic shorthair cat was presented for a right flank wound. On clinical examination, a single non-painful skin tear lesion with irregular edges was detected. During the examination, star-shaped cigarette paper-like skin lesions appeared spontaneously. An abdominal mass was also palpated. Feline skin fragility syndrome (FSFS) was suspected and a multicentric lymphoma was diagnosed by fine needle aspiration. The cat's condition declined and it died spontaneously. Post-mortem examination confirmed the diagnosis of lymphoma. Neoplastic lymphocytes were not observed in the skin. Histological analysis of the skin was consistent with the morphological aspects of FSFS. A possible direct link between the two conditions remains a matter of speculation, but this case report provides the first description of FSFS associated with multicentric follicular lymphoma. Thus, multicentric follicular lymphoma should be considered as a differential diagnosis in cats presenting with FSFS.

Melanoma diagnosis in dogs can be challenging due to the variety of histological appearances of canine melanocytic neoplasms. Markers of malignancy are needed. Receptor for activated C-kinase 1 (RACK1) was found to characterize melanomas in other mammals. We investigated the value of RACK1 detection in the classification of 19 cutaneous and 5 mucosal melanocytic neoplasms in dogs. These tumors were categorized as melanocytomas or benign and melanomas or malignant after evaluation of their morphology, mitotic index, and Ki-67 growth fraction. Using immunofluorescence, we confirmed microphthalmia-associated transcription factor (MITF) as a marker of normal and transformed melanocytic cells in dog tissues. All control (n ¼ 10) and tumoral (n ¼ 24) samples stained positively for MITF (34/34, 100%). Whereas RACK1 was not detected in healthy skin melanocytes, melanocytic lesions were all positive for RACK1 signal (24/24, 100%). RACK1 cytoplasmic staining appeared with 2 distinct distribution patterns: strong, diffuse, and homogeneous or granular and heterogeneous. All melanoma samples (13/13, 100%) stained homogeneously for RACK1. All melanocytomas (11/11, 100%) stained heterogeneously for RACK1. Immunohistochemistry was less consistent than immunofluorescence for all labelings in melanocytic lesions, which were often very pigmented. Thus, the fluorescent RACK1-MITF labeling pattern helped to distinguish melanomas from melanocytomas. Furthermore, RACK1 labeling correlated with 2 of 11 morphological features linked to malignancy: cell and nuclear size. These results suggest that RACK1 may be used as a marker in dog melanomas.

Tumor-targeting contrast agents may facilitate resection of solid neoplasms during fluorescence-guided surgery. Preliminary safety and imaging efficacy of the near-infrared fluorescent probe DA364 were evaluated during surgical resection of spontaneous solid tumors in 24 dogs. Intra-operative imaging was performed in situ and on excised specimens to evaluate fluorescence intensities of tumor and adjacent tissues. After standard-of-care tumor resection, the wound bed was imaged again, and additional tissue was excised if residual fluorescence was detected. DA364 was well tolerated after intravenous administration. The median tumorto-background ratio in situ for mammary tumors, mast cell tumors and sarcomas was 1.8 (range 1.2-3.9), 2.2 (range 1.0-5.6), and 4.2 (range 2.0-4.3), respectively. Qualitative intra-operative tumor identification was feasible in half of the cases. Remaining fluorescence was detected in four wound beds that contained residual disease, and in11 tumor-free wound beds, confirmed by histopathology. Overall, DA364 did not raise safety concerns and showed accumulation in different types of spontaneous tumors, showing potential to pinpoint residual disease. Larger clinical trials are necessary to select accurate dosing and imaging protocols for specific indications to evaluate the sensitivity and specificity of the agent.

Fetal hydrops or hydrops foetalis refers to an excessive fluid accumulation within the fetal extravascular compartments including the body cavities (Bellini and others 2009). It is an end-stage syndrome, well documented in human medicine, for which multiple aetiologies are recognised. Fetal sheep have been used as experimental models for this condition in human beings (andres and Brace 1990,

Bilateral multifocal corneal opacity was detected in a 4.5-year-old male captive gray mouse lemur (Microcebus murinus) without other clinical ocular changes. Histopathological examination revealed a severe diffuse granulomatous scleritis and focal keratitis with intralesional cholesterol, consistent with xanthomatous inflammation. This is the first report of xanthomatous inflammation in a gray mouse lemur. This condition may be the result of systemic factors (lipid metabolism disorders) and/or local predisposing factors such as hemorrhage or inflammation. The pathogenesis in this case could not be fully determined. Further studies on lemurs are required for a better understanding of their lipid metabolism, as well as for diagnosing and evaluating the incidence of xanthomatous inflammation in these species.

Background: In absence of ligand, PRA and PRB are evenly distributed in nuclei in cell lines. Upon ligand binding, PRA and PRB dimerizes and form discrete focal subnuclear distribution patterns, which are associated with transcriptional activation of PR. This pattern corresponds to the transcriptionally active form of PR and serves as an APR biomarker. The expression of APR in cell lines was demonstrated to be predictive of onapristone antiproliferative effects (Serin, Abs # 473, NCI-AACR-EORTC 2012). In this study the correlation of APR to the antiproliferative effects of different antiprogestins (Type I & type II, and steroidal/non-steroidal chemical structures) is examined. Method: T47D and CAMA-1, two PR expressing breast cancer cell lines, were grown in either FBS or Steroid Free FBS (SFFBS). In FBS, single agent anti-progestins were studied; in SFFBS, cell lines were stimulated with estradiol (E2) or progesterone (P4) and antiprogestins tested. All experiments were performed in duplicate. APR was analyzed at 6h and 30h using paraffin embedded cellular pellets, and processed with standard IHC techniques. Cellular viability was measured by the MTS assay at 30h, 4d and 7d. Antiprogestin drugs tested included: Aglepristone, Mifepristone, Onapristone, PF02413873, ZK230211, and ZM150271. Results: In the T47D cell line, in FBS between zero and ∼ 40% antiproliferative activity was observed from D1 to D7 for all antiprogestins. In SFFBS, T47D proliferation at D7 was increased >300% by E2 and >200% by P4. All antiprogestins opposed P4 and E2 proliferative effects at D7, with a max of 80% inhibition relative to control. In the CAMA-1 cell line, in FBS weak antiprogestin antiproliferative effect was observed (<20% inhibition); with SFFBS, P4 and E2 were weakly stimulatory and antiprogestins had an inconsistent and weak treatment effect. The effect of antiprogestins were not dose dependent. APR: in T47D and FBS, APR was observed at 6h consistently for PR A and PR B. At 30h, controls were APR positive, and with Aglepristone, Mifepristone and Onapristone treatment, the surviving cells were APR neg; PF02413873, ZK230211and ZM150271 APR effect was inconsistent. Specimens from SFFBS are under evaluation. For CAMA-1, in FBS PRA and PRB were weakly expressed i.e. in 5% of the cells; APR was always negative. Specimens from SFFBS are under evaluation. Conclusion: The cell line expressing APR, T47D, is sensitive to direct antiprogestins effect in FBS, to E2 and P4 growth stimulation in SFFBS. In T47D, there was an antagonism by all antiprogestins at D7 and APR status was reversed at 30 h completely in 3/6 cases and incompletely in 3/6. CAMA-1 does not express APR, is weakly stimulated by E2 and P4, and antiprogestins have inconsistent effects in this cell line. APR status is a predictor of antiprogestin action. Citation Format: Alexander Zukiwski, Erard Gilles, Guillaume Serin, Jacques Bosq, Charline Alleaume. Comparative assessment of in vitro activity and aactivated progesterone receptor (APR) biomarker predictivity for multiple antiprogestins. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3471. doi:10.1158/1538-7445.AM2015-3471