Endothelin A receptor blockade does not alter PSA secretion in prostate cancer cell lines

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. © 2004 Wiley‐Liss, Inc.