Karyotypic variability in rat kangaroo cell lines cultivated on fibronectin-coated surface

Abstract

Numerical and structural karyotypic variability was investigated in the NBL-3-17 and NBL-3-11 “markerless” rat kangaroo kidney cell lines cultivated on a fibronectin-coated surface. For the NBL-3-17 cell line grown on a fibronectin-coated surface for periods of 1, 2, 4 and 8 days, the chromosome number distribution changed. These changes involved a significant decrease in the frequency of cells with the modal chromosome number and an increase in the frequency of cells with a lower chromosome number. Many new additional structural variants of the karyotype (SVK) appeared. The observed alterations seem to be due to the predominant adhesion of cells with a lower chromosome number, disturbances of the mitotic apparatus and selection for SVK adapted to the changes in culture conditions. Detachment of cells from the fibronectin-coated surface followed by 5 days cultivation on a hydrophilic surface restored the control cell distribution. For the NBL-3-11 cell line cultured on the fibronectin-coated surface for 1, 2, 4 and 8 days, the numerical karyotypic variability did not change compared to control variants. For the NBL-3-17 cell line grown on a fibronectin-coated surface for 1, 2, 4 and 8 days, the frequency of chromosomal aberrations also did not change relatively to the control. In the NBL-3-11 cell line, the frequency of chromosomal aberrations under the same conditions significantly increased, mainly due to chromosome and chromatid breaks and dicentrics (telomeric associations). The differences in the numerical and structural karyotypic variability between NBL-3-17 (hypotriploid) and NBL-3-11 (hypodiploid) cell lines cultivated on fibronectin are discussed. It is assumed that the observed differences in the karyotypic variability between these cell lines were determined by the specific karyotypic structure of the NBL-3-11 cell line and the altered gene expression of the NBL-3-17 hypotriploid cell line caused by increased doses of certain functioning genes.