Author(s): Gibbons NB, Watson RW, Coffey RN, Brady HP, Fitzpatrick JM
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Abstract BACKGROUND: Resistance to apoptosis remains a significant problem in the treatment of prostate cancer. Heat-shock proteins (HSP) have been correlated with tumor progression. The role of HSP in prostate cancer resistance to apoptosis is unknown. METHODS: PC-3 and LNCaP prostate cancer cells were heat-shocked and then treated with or without diethyl-maleate, etoposide, cycloheximide, or 3 Gray irradiation. Percent apoptosis was assessed by propidium iodide DNA incorporation. Protein was also extracted for analysis by SDS-PAGE Western blotting. RESULTS: Western blotting confirmed an increase in HSP 27 and 72. These cells were resistant to both chemical- and radiation-induced apoptosis. Cycloheximide and specific oligonucleotides to HSP 72 blocked the increased expression of HSP 72 and the resistance to apoptosis. Mcl-1, Bcl-2, Bcl-X(L), and glutathione-S-transferase (GST) expression were increased in a time-dependent manner after heat shock. CONCLUSIONS: This study demonstrates that HSP expression, specifically HSP 72, inhibits apoptosis in prostate tumor cell lines, which may be mediated by the production of survival factors. Copyright 2000 Wiley-Liss, Inc.
This article was published in Prostate
and referenced in Journal of Gastrointestinal & Digestive System