Abstract: Objective To evaluate whether down-regulating antizyme inhibitor(AZIN) can regulate the expression of ornithine decarboxylase(ODC) and the proliferation of prostate cancer cell PC3 or not. Methods siRNA-AZIN transfected prostate cancer cell PC3, the level of antizyme(AZ), AZIN and ODC were measured by RT-PCR and westernblot. MTT was used to measure the proliferation of cells. Results The mRNA level of AZIN declined（P＜0.01）; the protein level of AZIN and ODC declined（P＜0.05）. Knockdown of AZIN significantly inhibited the proliferation of PC3（P＜0.05）. Conclusions Transfecting siRNA-AZIN can decrease the level of AZIN, then the decline level of ODC inhibits the proliferation of PC3.

Key words: antizyme inhibitor, ornithine decarboxylase, antizyme, siRNA