Internucleosomal DNA fragmentation. HUVECs treated with staurosporine (lane 2) or kept in suspension with serum deprivation (lane 3) for 6 hours were lysed and total cellular DNA was separated on a 2% agarose gel. HUVECs in lanes 2 and 3 show typical oligonucleosomal banding. Lanes M and 1 represent molecular weight markers (in kilobases) and normal HUVECs, respectively.