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Cytotoxic sensitivity to tumor necrosis factor‐α in PC3 and LNCaP prostatic cancer cells is regulated by extracellular levels of SGP‐2 (clusterin)
Author(s) -
Sintich Sharon M.,
Steinberg Joseph,
Kozlowski James M.,
Lee Chung,
Pruden Shaina,
Sayeed Sakina,
Sensibar Julia A.
Publication year - 1999
Publication title -
the prostate
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.295
H-Index - 123
eISSN - 1097-0045
pISSN - 0270-4137
DOI - 10.1002/(sici)1097-0045(19990501)39:2<87::aid-pros2>3.0.co;2-z
Subject(s) - lncap , clusterin , trypan blue , cytotoxic t cell , tumor necrosis factor alpha , extracellular , cytotoxicity , cell culture , biology , cancer cell , cytokine , endocrinology , medicine , apoptosis , cancer research , microbiology and biotechnology , immunology , in vitro , cancer , biochemistry , genetics
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.