[Expression of PIAS3 an inhibitor of activated STAT3 protein in human prostate cancer].

OBJECTIVE: To compare the expressions of PIAS3, an inhibitor of activated STAT3 protein in human androgen-dependent prostate cancer (ADPC) and androgen-independent prostate cancer (AIPC) and to explore the relationship between PIAS3 and the development of AIPC.

METHODS: (1) cDNA microarray technique was used to detect the PIAS3 gene in 20 samples of ADPC and 5 samples of AIPC obtained during operation. (2) Carcinoma of prostate (CaP) cells of the lines LNCaP, DU145, and PC3 were cultured and underwent semi-quantitative RT-PCR and Western blotting to detect the mRNA and protein expression of PIAS3 gene. (3) Ten samples of ADPC tissue and 5 samples of AIPC tissue obtained during operation underwent immunohistochemistry to observe the expression of PIAS3 protein.

RESULTS: (1) cDNA microarray technique showed that there were 17 genes significantly down-regulated and 22 were significantly up-regulated in the AIPC tissues in comparison with the AIPC tissues, (2) The mRNA and protein expressions of PIAS3 in the AIPC cells of the lines PC3 and DU145 were higher than those in the ADPC cells of the line LNCaP. (3) The expression of PIAS3 protein in the AIPC tissues was significantly higher than that in the ADPC tissues (P < 0.05).

CONCLUSIONS: Our results suggested that PIAS3 gene may play an important role in the development of androgen independent prostate cancer so as to promote the continuous cellular proliferation without androgen.