Experimental nude mouse model of human colorectal cancer liver metastases.

A nude mouse model (BALB/c) was established for investigating the production of hepatic metastases by human colorectal carcinoma (HCC) cells. The malignant potentials of 3 different HCCs derived from a primary tumor (HCC-P4733), a lymph node metastasis (HCC-M14328), and a hepatic metastasis (HCC-M1410) were investigated following implantation into the spleens of athymic nude mice. Cells of the HCC-M1410 line produced extensive liver tumors in all mice by 30 days after injection. Cells of the HCC-M14328 and HCC-P4733 lines produced few liver tumors in the inoculated mice and then only after a 90-day period. Isozyme and karyotype analyses ascertained the human origin of all the tumors. Studies with [125I]IdUrd-labeled HT-29 carcinoma cells suggested that tumor cells reached the liver shortly after injection into the spleen. Thus the production of HCC tumors in livers of nude mice was determined by the ability of HCC cells to proliferate in the liver parenchyma rather than by the ability of the cells to reach the liver. The results suggest that the intrasplenic injection of HCC cells can provide a valuable model for the study of the biology and therapy of the liver metastases.