Androgen receptor isoforms in human prostatic cancer tissue and LNCaP cell line

Aim: To investigate the androgen receptor (AR) isoform expressions in human prostatic cancer tissue and LNCaPcell line. Methods: With high resolution isoelectric focusing (IEF) method we demonstrated the different expres-sions of AR isoforms in human prostatic cancer tissues and LNCaP cell line. Results; Data were obtained from threeprostatic cancer specimens and the LNCaP cell line. Three types of AR isoforms were detected with pI values at 6.5,6.0, and 5.3. For the 3 prostatic cancer specimens, 1 sample showed all the three types of AR isoforms, the secondspecimen expressed at 6.5 and 6.0, and the third failed to show any type of isoforms. The LNCaP cell line expressedall the three AR isoforms. Binding of ~3H-dihydrotestosterone (~3H-DHT) to these three isoforms was inhibited by the ad-dition of 100-fold excess of DHT or testosterone, while not by progesterone, oestradiol and diethylstilboestrol. Conclu-sion : The expression of AR isoforms is different in different prostate cancer tissues, which may be related to the dif-ference in the effect of anti-androgen therapy in different patients. (Asian J Androl 2001 Sep; 3: 223 - 225)

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

Aim: 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 μmol/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 μmol/L antisense HSP70 oligomer for 48 hr or 8 μmol/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 μmol/L antisense HSP70 oligomer treatment for 48 hr or 8 μmol/L for 72 hr in Western blot, which was paralleled by decreased expression levels of anti-apoptotic protein bcl-2. Conclusion: 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.