Quiescence and increased adhesion after mammalian DNA transfection of human fibrosarcoma cells

When a population of human fibrosarcoma HT1080 cells was transfected with a mammalian expression vector and DNA pieces representing either the human whole genome or mouse bulk cDNA, there was a transient increase in the number of adhesive cells in the population. The number of cells with increased adhesion was proportional to the amount of transfected DNA; the increase occurred at a maximal frequency of between 10(-4) and 10(-5) per cell. Increased adhesion in these cells persisted for 9-12 days, corresponding to the period of highly efficient transient transfection, and was accompanied by arrest in cell division. Transfection of non-mammalian DNAs, reduction of transfected mammalian sequence length by restriction enzyme digestion, or omission of expression vector DNA did not permit these shifts in phenotype. The effects seen suggest that expression of specific transfected mammalian DNA sequences suppresses certain phenotypic characteristics in these transformed mammalian cells.