Spatiotemporal activation of caspase-dependent and -independent pathways in staurosporine-induced apoptosis of p53wt and p53mt human cervical carcinoma cells.
BACKGROUND
Caspase-dependent and -independent death mechanisms are involved in apoptosis in a variety of human carcinoma cells treated with antineoplastic compounds. Our laboratory has reported that p53 is a key contributor of mitochondrial apoptosis in cervical carcinoma cells after staurosporine exposure. However, higher mitochondrial membrane potential dissipation and greater DNA fragmentation were observed in p53wt (wild-type p53) HeLa cells compared with p53mt (mutated p53) C-33A cells. Here, we have studied events linked to the mitochondrial apoptotic pathway.


RESULTS
Staurosporine can induce death of HeLa cells via a cytochrome c/caspase-9/caspase-3 mitochondrial-dependent apoptotic pathway and via a delayed caspase-independent pathway. In contrast with p53wt cells, p53mt C-33A cells exhibit firstly caspase-8 activation leading to caspase-3 activation and Bid cleavage followed by cytochrome c release. Attenuation of PARP-1 [poly(ADP-ribose) polymerase-1] cleavage as well as oligonucleosomal DNA fragmentation in the presence of z-VAD-fmk points toward a major involvement of a caspase-dependent pathway in staurosporine-induced apoptosis in p53wt HeLa cells, which is not the case in p53mt C-33A cells. Meanwhile, the use of 3-aminobenzamide, a PARP-1 inhibitor known to prevent AIF (apoptosis-inducing factor) release, significantly decreases staurosporine-induced death in these p53mt carcinoma cells, suggesting a preferential implication of caspase-independent apoptosis. On the other hand, we show that p53, whose activity is modulated by pifithrin-alpha, isolated as a suppressor of p53-mediated transactivation, or by PRIMA-1 (p53 reactivation and induction of massive apoptosis), that reactivates mutant p53, causes cytochrome c release as well as mitochondrio-nuclear AIF translocation in staurosporine-induced apoptosis of cervical carcinoma cells.


CONCLUSIONS
The present paper highlights that staurosporine engages the intrinsic mitochondrial apoptotic pathway via caspase-8 or caspase-9 signalling cascades and via caspase-independent cell death, as well as through p53 activity.
Nicolier
Magali
M
CHU Jean Minjoz, EA 3181, IFR 133, Université de Franche-Comté, UFR Médecine et Pharmacie, Besançon, France.
Decrion-Barthod
Anne-Zélie
AZ
Launay
Sophie
S
Prétet
Jean-Luc
JL
Mougin
Christiane
C
D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002277:Carcinoma / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D061945:Caspase Inhibitors; D020169:Caspases / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D006801:Humans; D009154:Mutation; D015398:Signal Transduction / Q000187:drug effects*; D019311:Staurosporine / Q000494:pharmacology*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics* / Q000378:metabolism; D002583:Uterine Cervical Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology
D000970:Antineoplastic Agents; D061945:Caspase Inhibitors; D016159:Tumor Suppressor Protein p53; D020169:Caspases; D019311:Staurosporine