Related Experiment Videos
Heat-shock proteins inhibit induction of prostate cancer cell apoptosis
N B Gibbons1, R W Watson, R N Coffey
1Department of Surgery, Mater Misericordiae Hospital, Conway Institute of Biomedicine and Biomolecular Research, University College Dublin, Ireland.
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.