B7-H3 over expression in prostate cancer promotes tumor cell progression.

PURPOSE: We compared B7-H3 expression in benign prostatic hyperplasia and prostate cancer tissue specimens, and determined the effects of low B7-H3 expression on the PC-3 human prostate cancer cell line using RNA interference.

MATERIALS AND METHODS: B7-H3 expression in prostate specimens was determined by enzyme-linked immunosorbent assay. A PC-3 cell line with low B7-H3 expression was established by RNA interference to investigate the effect of B7-H3 on cell proliferation, adhesion, migration and invasion in vitro.

RESULTS: B7-H3 in tissue samples was significantly higher in the prostate cancer group than in the benign prostatic hyperplasia group (mean±SEM 174.73±56.80 vs 82.69±46.19 ng/gm, p<0.001). B7-H3 expression down-regulated by small interfering RNA decreased cell adhesion to PC-3 fibronectin more than 30%, and migration and Matrigel™ invasion up to 50%. No apparent impact was observed on cell proliferation.

CONCLUSIONS: B7-H3 is aberrantly expressed in prostate cancer. In addition to modulating tumor immunity, B7-H3 may have a novel role in regulating PC-3 cell progression.