Relation between cytogenetic characteristics of two human colonic adenocarcinoma cell lines and their ability to grow locally or metastasize or both: an experimental study in the nude mouse.

This study was aimed at elucidating the relation between the cytogenetic characteristics and the invasive ability of two human colonic adenocarcinoma cells lines, HT29 and CaCO2. These two cell lines have very different tumorigenic and metastatic capacities after intrasplenic injection into nude mice: high for HT29 and relatively weak for CaCO2. At the time of injection, cytogenetic studies of the two cell lines revealed shared abnormalities: paratriploidy with seven common extra chromosomes or chromosome regions and specific particularities. In HT29 cells, we observed a large marker of unknown origin, an isochromosome i(11)(q10) and 5, 12, 13, 15, 19, and (19q+) supernumerary chromosomes, and, finally, the absence of one chromosome 16. In CaCO2 cells, we observed a chromosome 1-derived marker with q24-31 duplication, 12q and 16 supernumerary chromosomes, and a der(16) marker. The most striking difference between the karyotypes of these two cell lines concerned chromosome 16 (under- and overexpressed in HT29 and CaCO2 cells, respectively), overexpression of chromosomes 13, 15, and 19 in HT29 cells, and the relative loss of 12p in CaCO2 cells. Although some differences may be due to the intrinsic characteristics of the stem line, the establishment of specific cytogenetic abnormalities points out the role of many regions of the genome in tumorigenic and metastatic capacities of malignant cells.