About the possible origin and mechanism of circulating DNA - Apoptosis and active DNA release

Background: In addition to cell lysis, apoptosis has been advanced as the origin of circulating DNA on the basis of several observations. Plasma or serum DNA often presents a ladder pattern reminiscent of that displayed by apoptotic cells when subjected to electrophoresis. However, the phenomenon of active release of DNA from cells might also be expected to result in a ladder pattern on electrophoresis. Non-dividing cells, such as lymphocytes, frog auricles and cultured cell lines including HL-60, spontaneously release a nucleoprotein complex within a homeostatic system in which newly synthesized DNA is preferentially released. Conclusion: In relation to DNA synthesis, the phenomenon of extracellular DNA in different culture conditions favors apoptosis or spontaneous active DNA release. (C) 2001 Published by Elsevier Science B.V.