Effect of polyamines on the uptake of poly (2′‐fluoro‐2′‐deoxyuridylic acid) by a mammalian cell line

Abstract

VERO cells can take up poly(dUfl)1 from the medium. The uptake involves surface adsorption and, most probably, intracellular penetration. Part of the poly(dUfl) is hydrolyzed during incubation with the cells but the hydrolysis products are not incorporated into de novo synthesized nucleic acids. The uptake is reduced by serum and stimulated by polycationic ionenes. The magnitude of stimulation depends on the structure of the ionene and the treatment regimen.

Effects of Ionenes on Interferon Induction by Poly(Inosinic Acid)·Poly(Cytidylic Acid)

“…DEAE-dextran greatly enhances the rate of uptake of (I), -(C),, by the cells (1, 3). Ionenes, too, exhibit uptake-stimulating properties, whereby 6,10-ionene is by far more effective than 6,6-and 3,3-ionenes (12). In neither case, however, has it been determined with certainty whether this uptake represents penetration of the polynucleotide across the cell membrane or only a cell surface adsorption.…”

“…In neither case, however, has it been determined with certainty whether this uptake represents penetration of the polynucleotide across the cell membrane or only a cell surface adsorption. DEAE-dextran and quarternary polyamines also protect various polynucleotides against hydrolysis by endonucleases (7,11,12,22), which can be present in the serum (14,20,25) and/or associated with the cells (24). In general, the stimulatory effects of polycations seem to be exerted through neutralization of the negative cell surface charges and consequent destabilization of the cell membrane (18,21) and through interaction with polynucleotides which may result in reduction of their repulsion from the cell surface (17), stabilization oftheir conformation, and protection against enzymatic degradation (11,17,21 …”