Establishment and characterization of androgen-independent human prostate cancer cell lines, LN-REC4 and LNCaP-SF, from LNCaP

1004 Aim: To investigate the mechanisms of androgen-independent growth in prostate cancer (PCa), we established two PCa cell lines, LN-REC4 and LNCaP-SF, from the androgen-dependent PCa cell line, LNCaP. Materials and methods: LN-Pre and LN-REC4 cells were generated from LNCaP tumors grown on intact and castrated scid mouse, respectively. After we cultured LNCaP cells under a steroid-free conditions for 6 months in vitro, LNCaP-SF cells were established. To show the character of LN-REC4 and LNCaP-SF cells, androgen sensitivity was investigated through examination of growth rate, and prostate-specific antigen (PSA), androgen receptor (AR), p21, p27, and cyclin D1 expression were examined by reverse transcription-polymerase chain reaction (RT-PCR). Angiogenesis assay in vitro was carried out using conditioned medium. To examine the expression level of vascular endothelial growth factor (VEGF), RT-PCR and enzyme-linked immunosorbent assay were also done. We also carried out cDNA microarray analysis to compare the differential expression between LNCaP and LNCaP-SF with or without androgen using IntelliGene DNA tip. Results and conclusions: LN-REC4 cells proliferated better than LNCaP cells in castrated mice and did well irrespective of castration, although responsiveness for androgen of LN-REC4 cells attenuated less than that of LNCaP cells in vitro. LNCaP-SF cells in castrated mice proliferated more rapidly than in normal mice. The PSA expression in LNCaP-SF cells was still induced by androgen. Expression of AR, p21, p27 and cyclin D1 were not changed in LN-REC4 and LNCaP-SF cells. Angiogenesis assay showed that both cells stimulated angiogenesis. LN-REC4 cells induced VEGF more than LNCaP and LN-Pre cells. However, expression of VEGF per cell in LNCaP-SF was lower than LNCaP cells, suggesting that other factors might be involved in angiogenesis. cDNA microarray analysis revealed that more than 200 androgen-regulated genes were up-regulated and down-regulated by androgen in LNCaP and LNCaP-SF cells. These cell lines might be a useful tool for researching androgen-independent growth and treatments of recurred PCa.