Establishment of rat hepatocellular carcinoma cell lines with differing metastatic potential in nude mice

For better understanding of cancer metastasis, we have established an in vi vo model for induction of highly metastatic hepatocellular carcinomas (HCC) in male F344 rats. From I tumor, 4 cell lines with differing metastatic po tential (C1, C2, C6, C5F) were established by subcloning using the limited- dilution cloning technique, Two other lines, N1 and L2, arose from another primary HCC and a lung metastatic lesion, respectively. Although cell adhes ion of each cell line in culture medium was different, tumors developing in the subcutis of nude mice after transplantation were all moderately differ entiated HCC with a trabecular pattern. On subcutaneous injection into nude mice, all 6 cell lines proved to be tumorigenic in the injection site and C5F was highly metastatic to the lung. With injection into the tail vein, N 1 and L2 formed frequent metastases in the lung as well as in lymph nodes. Using intraperitoneal injection, CI, C6, NI and L2 showed marked disseminat ed growth in the abdominal cavity with bloody ascitis. Northern blot analys is revealed expression of known metastasis-related genes, KA11 and heparana se, to be decreased in C5F, but no differences in expression of nm23-H1 wer e evident. A point mutation in the GSK-3 beta phosphorylation site of the b eta -catenin gene was found in L2. These transplantable HCC cell lines that have different metastatic ability should be useful for elucidation of mech anisms of metastasis. (C) 2001 Wiley-Liss, Inc.