ESTABLISHMENT OF AN EXPERIMENTAL LIVER METASTASIS MODEL BY INTRAPORTAL INJECTION OF A NEWLY DERIVED HUMAN PANCREATIC-CANCER CELL-LINE (KLM-1)

Conclusion: It is suggested that this liver metastasis model formed by a highly metastatic variant (KLM-1) is valuable for the study of the liver metastatic processes of human pancreatic cancer. Background: Liv er metastasis in the early postoperative period is one of the causes f or the poor prognosis of patients with resected pancreatic cancer. The refore, it is necessary to establish an experimental model to study th e mechanisms of liver metastasis in pancreatic cancer. Methods: Human pancreatic cancer cell lines (PK-1, PK-9, and KLM-1) were injected int o the portal vein of nude mice with or without pretreatment with antia sialo GM1, and colonies of liver metastases were counted for compariso n of metastatic ability of these cell lines. Biological and histopatho logical characteristics of the highly liver metastatic cell line (KLM- 1) were compared with its parent cell line (PK-1). Results: PK-1 cells and PK-9 cells rarely formed liver metastasis foci, but pretreatment with antiasialo GM1 promoted liver metastasis. KLM-1 cells formed live r metastases at the rate of 70% even without antiasialo GM1 pretreatme nt. KLM-1 cells had such biological characteristics as short doubling time, short lag phase, and resistance to NK cytotoxicity. After intrap ortal injection of I-125-labeled KLM-1 cells, radioactivity as well as micrometastases were detected in the liver at 72 h.