It has been shown previously that ovine prion protein (PrP C ) renders rabbit epithelial RK13 cells permissive to the multiplication of ovine prions, thus providing evidence that species barriers can be crossed in cultured cells through the expression of a relevant PrP C . The present study significantly extended this observation by showing that mouse and bank vole prions can be propagated in RK13 cells that express the corresponding PrP C . Importantly, the respective molecular patterns of abnormal PrP (PrP res ) and, where examined, the neuropathological features of the infecting strains appeared to be maintained during the propagation in cell culture. These findings indicate that RK13 cells can be genetically engineered to replicate prion strains faithfully from different species. Such an approach may facilitate investigations of the molecular basis of strain identity and prion diversity.

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Despite circumstantial evidence that prions can be found extracellularly or at the surface of infected cells, little is known about how these infectious agents spread from cell to cell. In order to gain better insight into this critical issue, this study used two different cell lines (neuroglial MovS and epithelial Rov cells) that have previously been shown to be permissive for ovine prion multiplication. Co-culture of infected cells and uninfected target cells at a ratio of 1 : 9 resulted in total infection of MovS cells within 10 days but not of Rov cell cultures, suggesting that the efficiency of prion dissemination may vary greatly depending on the type of permissive cell. Analysis of the spatial distribution of the newly infected cells revealed that, although long-range spread could also occur, cells proximal to the infected donor cells consistently accumulated more abnormal PrP, consistent with preferential infection of nearby cells. This experimental approach, focused on dissemination among living cells, could help in the analysis of mechanisms involved in the cell-to-cell spread of prion infections. METHODS Antibodies. Immunoblot analysis of PrP was performed with the monoclonal antibody (mAb) ICSM18 (Beringue et al., 2003).

Androgen deprivation therapy (ADTh) remains a mainstay of prostate cancer treatment, but its efficacy is bypassed by mechanisms that are not fully understood. In human prostate cancer cells, androgen glucuronidation, catalyzed by the two UDP-glucuronosyltransferase (UGT) enzymes UGT2B15 and UGT2B17, is the major androgen inactivation pathway. In this study, we investigated the effect of ADTh on androgen glucuronidation to evaluate its potential clinical utility for prostate cancer prognosis or therapy. UGT2B15 and UGT2B17 expression was evaluated in prostate cancer specimens from untreated or treated patients and in cell models of prostate cancer exposed to clinically relevant antiandrogens. UGT2B15 and UGT2B17 protein levels in prostate were increased after 5 months of ADTh when compared with specimens from untreated patients. UGT2B15 expression remained elevated for up to 12 months, but UGT2B17 returned to initial levels as soon as after 6 months. Several androgen receptor (AR) antagonists tested caused a dose-and time-dependent stimulation of UGT2B15 and UGT2B17 expression and androgen glucuronidation in prostate cancer cell lines. The role of AR in these regulatory events was confirmed using AR-deficient LNCaP cells, in which UGT2B attenuation reduced the antiproliferative effects of AR pharmacologic antagonists. Through this combination of clinical and functional investigations, our work revealed that ADTh stimulates a local androgen metabolism in prostate cells, establishing a foundation to evaluate the potential of UGT2B15 and UGT2B17 as drug targets and/or molecular markers for ADTh responsiveness and maintenance in prostate cancer. Cancer Res; 73(23); 6963-71. Ó2013 AACR.