Two in situ labeling techniques reveal different patterns of DNA fragmentation during spontaneous apoptosis in vivo and induced apoptosis in vitro.

Abstract

Thus our data show that the DNA fragments formed during spontaneous apoptosis in breast tissues and preferentially during VP16 induced apoptosis in HL60 cells are either 5' recessed or blunt ended, being distinctly different from 3' recessed fragments seen in NHL and HNSCC or with a lesser frequency in VP 16 treated HL60 cells. Specific fragmentation patterns could be a result of activation of different endonucleases which as indicated by our data could be tissue specific and may be differentially activated by different chemotherapeutic agents. Therefore, screening for the presence of specific endonucleases in different tissues and for agents specifically activating them would have major clinical implications.