Comparative intraosseal growth of human prostate cancer cell lines LNCaP and PC-3 in the nude mouse

Background: More than 75% of patients with advanced prostate carcinoma have skeletal involvement which is the principal metastatic site and the major complication of this disease. The goal of this work was to compare the osseous metastasis of androgen-sensitive and insensitive prostate cancers in the nude mouse. Materials and methods: Androgen-sensitive LNCaP or -insensitive PC-3 human prostate carcinoma cells were injected directly into the femur medullas of male nude Beige mice, the animals were then sacrificed at successive time intervals to study the gross and microscopic characteristics of the established tumors. Results: LNCaP and PC-3 both colonized in the bone marrow within a week, then gradually expanded to the entire bone medulla followed by osseous infiltration to produce obvious symptoms in the affected extremities. Based on the morphology, both osteoblastic and osteolytic changes occurred during the course of tumor progression. In addition, PC-3 tumors eventually broke through the bone cortex, invaded the surrounding tissues, and metastasized to the regional lymph nodes. In contrast, LNCaP remained localized within the bone, and appeared to eventually regress and die after displacing the normal bone marrow cells. Immunohistochemically, LNCaP tumors were consistently positive for prostate-specific antigen in bone metastasis, while PC-3 tumors were negative. Tumor cell nuclei of both PC-3 and LNCaP hybridized to a human repealed sequence DNA probe indicating that the proliferating malignant cells were of human origin. Conclusions: These cancel cell lines produced a high incidence of growth in the bone that differed in histogenesis. The relative malignancy of these cell lines was demonstrated in this model.