Acute apoptosis by cisplatin requires induction of reactive oxygen species but is not associated with damage to nuclear DNA.
Cisplatin is a broad-spectrum anticancer drug that is also widely used in experimental studies on DNA damage-induced apoptosis. Induction of apoptosis within 24-48 hr requires cisplatin concentrations that are at least one order of magnitude higher than the IC(50). Here, we show that such high, apoptosis-inducing cisplatin concentrations induce cellular superoxide formation and that apoptosis is inhibited by superoxide scavengers. The same concentration limit and the requirement for superoxide are also true for induction of caspase activation in enucleated cells (cytoplasts), showing that cisplatin-induced apoptosis occurs independently of nuclear DNA damage. In contrast, lower cisplatin concentrations, which do not induce acute apoptosis, are sufficient for induction of DNA damage signaling. We propose that the antiproliferative effects of cisplatin at IC(50) doses involve premature senescence and secondary, nonstress-induced apoptosis. The higher doses currently used in in vitro studies lead to acute, stress-induced apoptosis that involves induction of superoxide but is largely DNA damage-independent.
Berndtsson
Maria
M
Department of Oncology and Pathology, Cancer Center Karolinska, Karolinska Institute and Hospital, Stockholm, Sweden.
Hägg
Maria
M
Panaretakis
Theocharis
T
Havelka
Aleksandra Mandic
AM
Shoshan
Maria C
MC
Linder
Stig
S
D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism; D053148:Caspase 3 / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism*; D002945:Cisplatin / Q000494:pharmacology*; D003593:Cytoplasm / Q000378:metabolism; D004249:DNA Damage / Q000187:drug effects*; D004789:Enzyme Activation / Q000187:drug effects; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D045325:HCT116 Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D017382:Reactive Oxygen Species / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000502:physiology
D000970:Antineoplastic Agents; D017382:Reactive Oxygen Species; D016159:Tumor Suppressor Protein p53; D053148:Caspase 3; D002945:Cisplatin; D002118:Calcium