Chromosomal instability and progressive loss of chromosomes in HeLa cells during adaptation to hyperoxic growth conditions.
By sequential selection for resistance to stepwise increased levels of atmospheric O2, a genetic variant of HeLa cells was obtained capable of stable proliferation under an atmosphere containing 80% O2 (HeLa-80). This cell strain has previously been characterized in terms of growth characteristics, morphology and antioxidant status (Joenje et al., 1985). In an attempt to find cytogenetic clues possibly related to the O2-tolerant character, metaphases of HeLa-80 cells were analyzed and compared to the parental (HeLa-20) strain. Numerical analysis revealed a progressive decrease in the number of chromosomes per cell during selection for O2 resistance, from a modal number of 112 in HeLa-20 cells to 84 in HeLa-80 cells. Cytogenetic endpoints for genetic damage revealed increased frequencies in HeLa-80 cells of both chromosomal aberrations (29.7 versus 6.9% aberrant cells) and sister-chromatid exchanges (0.46 +/- 0.13 versus 0.31 +/- 0.10 SCE/chromosome). G-banded metaphases failed to reveal cytogenetic evidence of gene amplification (homogeneously staining regions, double minutes) in the karyotype of HeLa-80 cells.
Institute of Human Genetics, Free University, Amsterdam, The Netherlands.
J J
JJ
Gille
H
H
Joenje
D002455:Cell Division / Q000187:drug effects; D002871:Chromosome Banding; D002872:Chromosome Deletion; D004361:Drug Tolerance; D006367:HeLa Cells; D006801:Humans; D010100:Oxygen / Q000494:pharmacology*; D012854:Sister Chromatid Exchange
D010100:Oxygen