Establishment of a novel species- and tissue-specific metastasis model of human prostate cancer in humanized non-obese diabetic/severe combined immunodeficient mice engrafted with human adult lung and bone.

Bone is the most common site of metastasis in prostate cancer (PC), and to generate an animal model to investigate the basis of the unique organ tropism of PC cells for bone, we engrafted humanized non-obese diabetic/severe combined immunodeficient (NOD/SCID-hu) mice with human adult bone (HAB) and lung (HAL). Human PC cell lines LNCaP (1 x 10(7)) and PC-3 (5 x 10(6)) were injected into male NOD/SCID-hu mice via the lateral tail vein at 3-4 weeks after implantation. At 8 weeks after the injection, LNCaP and PC-3 cells had metastasized specifically to HAB in 35 and 65%, respectively, of the mice. The tumors formed by LNCaP appeared to be the osteoblastic type, whereas the PC-3 tumors consisted of osteolytic lesions without any surrounding osteogenic response. A feature of experimental metastasis of PC in NOD/SCID-hu mice was its specificity for HAB tissue. Human PC cells had no or very low metastatic potential in regard to implanted HAL, mouse bone, or native mouse bone. These findings indicate that metastasis of PC cells to HAB is both species and tissue specific. The availability of this small animal model could provide a useful tool for identifying and analyzing important features of the human PC metastatic process that cannot be addressed in conventional metastasis models.