Differential regulation of phosphatidylserine externalization and DNA fragmentation by caspases in anticancer drug-induced apoptosis of rat mammary adenocarcinoma MTLn3 cells22Abbreviations: PS, phosphatidylserine; AV, annexin V; PI, propidium iodide; LDH, lactate dehydrogenase; zVAD-fmk, benzyloxycarbonyl-Val-Ala-DL-Asp-fluoromethylketone; PKC, protein kinase C; PARP, poly(ADP) ribose polymerase; AMC, 7-amino-4-methylcoumarin; alpha-MEM, alpha minimal essential medium; and FBS, fetal bovine serum.