[Establishment of a transplantable rat colon cancer and a model of metastasis]

A new colon cancer metastasis model was developed in inbred rat. Fischer F344 rats receiving 20mg/kg of 1,2-dimethylhydrazine per week for 20 weeks developed adenocarcinoma of the colon. The tumor has been successfully transplanted by subcutaneous inoculation for 9 generations to the present. Pathologically this transplantable tumor (TRC-1) was moderately differentiated adenocarcinoma. Single cell suspensions were obtained from TRC-1. Tumor cells (8 x 10(6)) inoculated into the portal vein of syngenic rats developed no liver metastasis. The subcutaneous tumor was excised and cultured in RPMI-1640 medium with 10% FCS. To the present, the cells were cultured for 2 years. Electron microscopic study revealed microvilli, desmosomes and intermediate filaments. The cultured cells (TRCC-1) injected into the portal vein produced liver metastases. Similarly, the cells injected into the tail vein produced lung metastases. And the cells injected into the peritoneal cavity produced peritoneal dissemination. This rat model seemed to be useful in studying the treatment for colon cancer metastasis.