[Comparative study of metastasis-associated characteristics of tumor cells with different metastatic capacities]

To investigate the relationship between metastatic potential and other biological properties of tumor cells.

Three human colon carcinoma cell lines WiDr, HT-29 and HT-29b with similar genetic background were hetero-transplanted into nude rats by mesenteric intravenous inoculation and their dissemination was observed. Homotypic aggregation, target organ colonization, cell proliferation and apoptosis, expression of c-erbB-2, EGFR, p53 and mucin, CA19-9 and CEA of tumor cells of these 3 cell lines were comparatively studied by using three dimensional spheroid cell culture, TUNEL and immunocytochemistry.

The three cell lines differed significantly in their metastatic capacities. HT29b and HT29 cells metastasized to the liver, lungs and other parts of the body but the metastasis was more marked in the former than in the latter. WiDr cells did not metastasize at all. In 50%-60% of nude rats with HT-29 and HT29b xenografts, tumor cells were colonized in the liver while no such colonization was seen in rats with WiDr xenograft. The metastatic potential was found to be negatively correlated with the in vitro homotypic aggregating capacity of the tumor cells. The tumor cells with high metastatic potential were found to have higher cell proliferation index but lower cell apoptosis index as compared to those with low metastatic potential. Higher expression of EGFR and mutant p53 in tumor cells with high than in those with low metastatic potential was also observed. No such difference existed in the expression of mucin, CA19-9 and CEA.

The metastatic capacity of colon carcinoma is associated with such biological properties of tumor cells as homotypic adhesion, target organ colonization, status of cell proliferation and apoptosis, and expression of EGFR and mutant p53.