Orthotopic implantation of human prostate cancer cell lines: A clinically relevant animal model for metastatic prostate cancer

BACKGROUND: To study the metastatic behavior of human prostate cancer cell lines, orthotopic injection in nude mice was performed. METHODS: Local tumor growth, metastasis formation, prostate-specific antigen, and androgen receptor expression were examined. RESULTS: Hormone-independent cell lines (PC-3, PC-3-125-IL, and TSU-Pr1) were highly tumorigenic and had a higher rate of lymph node metastasis after orthotopic than after subcutaneous implantation. PC-3 cell lines also consistently metastasized to the lungs. The androgen-sensitive LNCaP cell line showed local growth in 7 of 10, and lymph node metastasis in 4 animals. Significant serum PSA levels and strong receptor expression in primary and metastatic tumor tissues were observed. CONCLUSIONS: These results demonstrates that orthotopic implantation of human prostate cancer cell lines, including LNCaP, reproducibly leads to metastasis formation in nude mice.