Figure 4. Effect of genistein on PGE₂ levels and cell growth.

Panel A: Sub-confluent cultures of LNCaP, PC-3 and the primary normal prostatic epithelial cells E-PZ-1 and E-PZ-5 were treated with 0.01% ethanol vehicle (control, Con) or 10 μM genistein (G) for 72 h. Conditioned media from vehicle and genistein-treated cultures were collected and PGE₂ levels were determined using an EIA kit as described in Materials and Methods. Values are given as a percent of PGE₂ levels in vehicle-treated control set at 100%, which corresponded to 0.262 ± 0.04 pg/μg protein in LNCaP, 5.9 ± 1.2 pg/μg in PC-3, 175 ± 8.6 pg/μg in E-PZ-1and 0.029 ± 0.003 pg/μg in E-PZ-5 cells. Values represent mean ± SE from three experiments. *p< 0.05 and ** p< 0.01 as compared to control.

Panel B: Primary prostatic epithelial cells derived from normal human prostate tissue were seeded and cultured in defined growth media containing vehicle (0.01% ethanol) or 10 μM genistein. Cell growth at the end of 10 days was determined by a high-density growth assay as described in Materials and Methods. Values represented are mean ± SE from three experiments. *** p< 0.001 as compared to control.

Panel C: Semi-confluent LNCaP cells cultures in RPMI + 2% FBS were treated with 0.1% ethanol vehicle (control, Con), arachidonic acid (AA, 3 μM), PGE₂ (10 μM) or PGF_2α (10 μM) in the absence or presence of 10 μM genistein (G) added to the media. Fresh media and the various agents were replenished at the end of 3 days. Cell growth was determined at the end of 6 days by measuring DNA content as described in Materials and Methods. Values are expressed as μg of DNA/well and represent mean ± SE of at least three experiments. * p< 0.05, ** p< 0.01 and *** p< 0.001 when compared to vehicle. +++ p< 0.001 when compared to AA, PGE₂ or PGF_2α alone.