Establihment of an experimental liver metastasis model by intraportal injection of a newly derived human pancreatic cancer cell line (KLM-1)

Summary 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 Liver metastasis in the early postoperative period is one of the causes for the poor prognosis of patients with resected pancreatic cancer. Therefore, it is necessary to establish an experimental model to study the mechanisms of liver metastasis in pancreatic cancer. Methods Human pancreatic cancer cell lines (PK-1, PK-9, and KLM-1) were injected into the portal vein of nude mice with or without pretreatment with antiasialo GM1, and colonies of liver metastases were counted for comparison of metastatic ability of these cell lines. Biological and histopathological 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 liver metastases at the rate of 70% even without antiasialo GM1 pretreatment. KLM-1 cells had such biological characteristics as short doubling time, short lag phase, and resistance to NK cytotoxicity. After intraportal injection of¹²⁵I-labeled KLM-1 cells, radioactivitiy as well as micrometastases were detected in the liver at 72 h.