BACKGROUND SGP‐2 is a ubiquitous secreted glycoprotein that prevents cellular apoptosis. This study was carried out to determine the extracellular action of SGP‐2 in a model of tumor necrosis factor‐α (TNF)‐induced cytotoxicity using two human prostatic cancer lines, LNCaP and PC3. These two lines were selected because LNCaP cells are highly sensitive to the cytotoxic effect of TNF, while PC3 cells are resistant to TNF at 24 hr. METHODS Cells were cultured in the presence or absence of TNF (10 ng/ml). LNCaP cells were treated with varying concentrations of exogenous SGP‐2, while PC3 cells were treated with antisera to SGP‐2 with and without exogenous SGP‐2. Following a 24‐hr treatment, cultures were assessed by counting of cell number and by the trypan blue exclusion assay. RESULTS Western blot analysis of conditioned media revealed that PC3 secreted more SGP‐2 than did LNCaP. The sensitivity to TNF in LNCaP cells was reduced by the addition of exogenous SGP‐2. PC3 cells became sensitive to TNF when SGP‐2 antibody was added to the culture. The effect of SGP‐2 antibody on PC3 cells was reversed by the addition of exogenous SGP‐2 to the culture. CONCLUSIONS These results suggest that SGP‐2 can act as an extracellular mediator of anti‐TNF‐induced cytotoxicity. Prostate 39:87–93, 1999. © 1999 Wiley‐Liss, Inc.

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BACKGROUND LNCaP cells are androgen‐sensitive human prostate cancer cells. They are characterized by a bell‐shaped growth curve in response to increasing doses of dihydrotestosterone (DHT) in culture. At a low concentration of DHT (0.1 nM), these cells show an increase in proliferation, but their growth is arrested at a high concentration (100 nM) of DHT. Results of our previous study demonstrated that the inhibitory effect of DHT at a high concentration was mediated through the action of TGF‐β1. The objective of the present study was to elucidate the mechanism of the proliferative effect of DHT in LNCaP cells. METHODS AND RESULTS DHT stimulated LNCaP proliferation only when cells were cultured in the presence of serum. In serum‐free cultures, the characteristic DHT‐induced proliferation was not observed. The addition of neutralizing antibody against FGF‐2 (basic fibroblast growth factor) was able to inhibit this DHT‐induced proliferation. These results suggest that the proliferative effect of DHT was mediated through the action of FGF‐2. However, results of the reverse transcriptase polymerase chain reaction indicated that LNCaP cells did not express FGF‐2 message. As a result, the source of FGF‐2 in these cultures must be the serum supplemented in the culture media. FGF‐2 can bind to heparin sulfate chains within the extracellular matrix (ECM). In cultures treated with exogenous heparin, the proliferative effect of DHT was abolished. These results led to the development of the hypothesis that DHT treatment mediates the release of FGF‐2 entrapped in the ECM through increased heparinase activity. The addition of heparinase to cultures of LNCaP cells, in the absence of DHT, was able to stimulate cell proliferation. Moreover, 0.1 nM DHT caused a significant increase in heparinase activity. CONCLUSIONS These results provide a possible mechanism for DHT action in LNCaP cells. In the absence of DHT, FGF‐2 in culture was trapped in the extracellular matrix and was not available to interact with LNCaP cells. However, in the presence of 0.1 nM DHT, heparinase activity in the culture was elevated and, as a result, it liberated the trapped FGF‐2 which, in turn, stimulated proliferation in LNCaP cells. Prostate 44:124–132, 2000. © 2000 Wiley‐Liss, Inc.

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In order to determine if hantaviruses were present in mice and other small mammals in Indiana (USA), small mammals were trapped in Brown, LaPorte, Tippecanoe and Whitley counties. Sixty-seven small mammals were trapped during August and September 1994. Sixty-three Peromyscus leucopus, one Microtus pennsylvanicus, one Zapus hudsonius and two Blarina brevicauda were captured and tested for hantaviruses. Six P. leucopus were found to have antibody to Sin Nombre virus (SN) by IgG ELISA, and a 139 bp fragment of SN-like hantavirus was amplified from five of them. All six of the positive P. leucopus were from LaPorte County. No other small mammals had evidence of infection with SN virus. This study presents the first report of Sin Nombre-like hantavirus in P. leucopus from Indiana.