ABSTRACT
PURPOSE: In order to characterize the effects of growth factors (EGF, bFGF, KGF) on the regulation of the PSA secretion and the PSA mRNA expression of androgen- dependent LNCaP prostate cancer cell line in serum-free conditions. MATERIALS AND METHODS: LNCaP cells at a concentration of 1x104cells/well, suspended in T-medium containing 2% TCM, were seeded in 24 well plates and were exposed to four different concentrations of these growth factors to evaluate the molecular basis of PSA secretion. Cell numbers were evaluated by crystal violet assay on day 5. PSA concentrations in conditioned medium were determined on day 5, and PSA/cell number was also calculated to measure net PSA secretion per cell. PSA mRNA expression of LNCaP was assessed by RT-PCR and Northern blot analysis on day 5. RESULTS: bFGF and KGF had significant stimulatory effects (p<0.05) on the proliferation of LNCaP. However, EGF had minimal, not significant, growth stimulatory effects. EGF, bFGF and KGF did not increase the PSA secretion of LNCaP and no apparent increase or decrease in the steady-state levels of the PSA mRNA expression of LNCaP could not be detected in spite of addition of EGF, bFGF and KGF. CONCLUSIONS: bFGF and KGF, not EGF, directly stimulate the proliferation of LNCaP cells. However, bFGF and KGF as well as EGF do not affect the PSA secretion and the PSA mRNA expression of androgen-dependent LNCaP in the absence of androgenic milieu. The regulation of the PSA secretion and the PSA mRNA expression of LNCaP is not directly associated with EGF, bFGF and KGF.
Subject(s)
Blotting, Northern , Cell Count , Cell Line , Culture Media, Conditioned , Epidermal Growth Factor , Fibroblast Growth Factor 2 , Fibroblast Growth Factor 7 , Gentian Violet , Intercellular Signaling Peptides and Proteins , Keratinocytes , Prostate , Prostatic Neoplasms , RNA, MessengerABSTRACT
PURPOSE: The growth and PSA secretion of prostate carcinoma is predominantly regulated by androgens. However, locally produced growth factors(GFs) also have been shown to play a crucial role in the proliferation of androgen-dependent prostatic tumor cells. Androgen has been proposed to stimulate the cell proliferation and PSA secretion by modulating the activity of some of these growth factors. The objectives of this study are to determine the effects of various GFs (epidermal growth factor; EGF, basic fibroblast growth factor; bFGF, keratinocyte growth factor; KGF, hepatocyte growth factor; HGF) on the growth and PSA secretion of androgen-dependent LNCaP prostate cancer cell line. MATERIALS AND METHODS: To determine the effects of EGF, bFGF, KGF and HGF on the growth and PSA secretion of LNCaP, LNCaP cells at a concentration of 3 x 103 cells/well, suspended in T-medium containing 2% TCM, were seeded in 96 well plates. Cells were exposed to six different concentrations (0.5, 1, 5, 10, 20 and 40 ng/ml) of GFs. Cell numbers were evaluated by crystal violet assay on day 3, 5 and 7, and PSA concentrations in conditioned medium were determined on day 5. RESULTS: EGF and HGF had minimal, not significant, stimulatory effects on the growth of LNCaP. However, bFGF and KGF had significant growth stimulatory effects (P<0.05). EGF, bFGF, KGF and HGF did not have any stimulatory effects on the PSA secretion of androgen-dependent LNCaP cell line. CONCLUSIONS: bFGF and KGF, not EGF and HGF, directly stimulate the growth of LNCaP cells. However, bFGF and KGF as well as EGF and HGF do not affect the PSA secretion of LNCaP. There seems to be another signal transduction pathway, which is not associated with GFs mentioned above, for PSA secretion of androgen-dependent LNCaP cell line.