AIMTo investigate the effect of abrogating heat shock protein (HSP) 70 expression by antisense HSP70 oligonucleotides treatment on human androgen-independent prostate cancer cell line PC-3m growth.

METHODSPC-3m cells were treated with 0-16 mmol/L antisense HSP70 oligomers for 0-100 hr. Cell growth inhibition was analyzed using a trypan blue dye exclusion test. Apoptotic cells were detected and confirmed by flow cytometric analysis and DNA fragmentation analysis. The protein expression of HSP70 and bcl-2 affected by antisense HSP70 oligomers were determined using Western blot.

RESULTSAntisense HSP70 oligomer induced apoptosis and then inhibited proliferation of PC-3m cells in a dose- and time-dependent manner. Ladder-like patterns of DNA fragments were observed in PC-3m cells treated with 10 mmol/L antisense HSP70 oligomer for 48 hr or 8 mmol/L for 72 hr on agarose gel electrophoresis. Antisense HSP70 oligomer pretreatment enhanced the subsequent induction of apoptosis by heat shock in PC-3m cells. In addition, undetectable HSP70 expression was observed at a concentration of 10 mmol/L antisense HSP70 oligomer treatment for 48 hr or 8 mmol/L for 72 hr in Western blot, which was paralleled by decreased expression levels of anti-apoptotic protein bcl-2.

CONCLUSIONHSP70 antisense oligomer treatment abrogates the expression of HSP70, which may disrupt HSP70-bcl-2-interactions and further down-regulate bcl-2 expression, in turn inducing apoptosis and inhibiting cell growth in PC-3m cells.