OBJECTIVETo detect the expression of prostate cancer antigen-1 (PCA-1) in prostate cancer, and to analyze the effects of downregulation of PCA-1 expression on malignant biological behavior of prostate cancer LNCaP cells, and to explore their possible molecular mechanisms.

METHODSPCA-1-siRNA and control siRNA were transfected into LNCaP cells with lipofectamine 2000. The cell cycle, proliferation and migration were determined by methyl thiazolyl tetrazolium (MTT) assay, flow cytometry and Transwell chambers, respectively. Western blotting was used to detect the expression of cyclin E, matrix metallopeptidase 9 (MMP-9) and p21. Immunohistochemistry was used to detect the expression of PCA-1 protein in 126 cases of prostate cancer and 88 cases of benign prostatic hyperplasia (BPH).

RESULTSThe positive rate of PCA-1 expression was 77.8% (98/126) in prostate cancer, and 10.2% (9/88) in BPH, and its expression was not significantly related to age, prostate specific antigen (PSA), Eastern Cooperative Oncology Group (ECOG) score (P > 0.05), and was associated with Gleason score, TNM staging and bone metastasis (P < 0.05). Downregulation of PCA-1 expression inhibited cell proliferation, arrested cell cycle at S phase and decreased cell migration of LNCaP cells. The downregulation of PCA-1 expression decreased the expression of Bcl-xl, cyclin E and MMP-9 proteins, but increased the expression of p21 proteins.

CONCLUSIONSPCA-1 may play an important role in the development of prostate cancer. The downregulation of PCA-1 expression can lead to changes in the proliferation, cell cycle and migration of prostate cancer LNCaP cells, and these effects may be associated with the decrease of Bcl-xl, cyclin E and MMP-9 proteins and increase of p21 protein.