Abrogation of heat-shock protein (HSP)70 expression induced cell growth inhibition and apoptosis in human androgen-independent prostate cancer cell line PC-3m.
OBJECTIVE
To 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.


METHODS
PC-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.


RESULTS
Antisense 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.


CONCLUSIONS
HSP70 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.
Zhao
Zhi-Gang
ZG
Department of Urology, Shantou University Medical College, 515031, China. zgzhaodr@yahoo.com.cn.
Ma
Qing-Zheng
QZ
Xu
Chun-Xiao
CX
D000728:Androgens / Q000502:physiology*; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D015153:Blotting, Western; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004273:DNA, Neoplasm / Q000096:biosynthesis / Q000302:isolation & purification; D004305:Dose-Response Relationship, Drug; D004587:Electrophoresis, Agar Gel; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis*; D006801:Humans; D007700:Kinetics; D008297:Male; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology*
D000728:Androgens; D004273:DNA, Neoplasm; D018840:HSP70 Heat-Shock Proteins; D016376:Oligonucleotides, Antisense