ABSTRACT
BACKGROUND: Some men treated with atrasentan (ABT-627), an endothelin A (ETA) receptor inhibitor, had declines in their serum PSA levels. It is our hypothesis that this decrease is due to anti-tumoral activity and not a reduction in PSA secretion at the cellular level. METHODS: Two PSA secreting prostate cancer cell lines (LAPC4 and LNCaP) were treated with atrasentan and an ETB receptor antagonist (A192621) in varying concentrations (10(-6)-10(-10) M) and PSA levels were measured in the culture media. RESULTS: LNCaP and LAPC4 cells both express ETA receptors. Neither the ETA or ETB antagonist altered PSA secretion, while addition of DHT, a positive control, produced a marked increase in PSA secretion. CONCLUSIONS: Blockade of the ETA receptor does not affect the secretion of PSA in prostate cancer cell lines.
