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Characterization of distinct consecutive phases in non-genotoxic p53-induced apoptosis of Ewing tumor cells and the rate-limiting role of caspase 8.
Oncogene. 2000 Aug 24; 19(36):4096-107.O

Abstract

To dissect the p53-dependent apoptotic pathway, events following induction of temperature sensitive (ts) p53val138 were studied in a Ewing tumor cell line. Transcriptional deregulation of p53 targets first observable after 1 h at 32 degrees C preceded activation of caspases and the break-down of mitochondrial respiratory activity. Activation of caspases was first observed 4 h after p53 induction. Using peptide inhibitors we identified activation of caspase 8 upstream of caspases-9 and -3. Although the caspase 8 specific inhibitor z-IETD.fmk did not affect translocation of BAX to the mitochondrial membrane and cytochrome C release it almost completely blocked cleavage of the prototype caspase substrate PARP and DNA fragmentation while enforcing mitochondrial depolarization and production of reactive oxygene species (ROS). Activation of caspase 8 did not involve death-domain receptor signaling. Expression of BCL2 only partially suppressed caspase activation but blocked apoptosis. Replacement of the N-terminus of p53val138 by the related VP16 transactivation domain created a ts p53 with a tanscriptional activity indistinguishable from p53val138 until the time of caspase activation. However, the VP16 - p53 fusion failed to trigger caspases and subsequent induction of the ROS producing gene pig3 paralleled by complete loss of apoptotic activity. These results indicate that p53-dependent transcriptional deregulation, triggering of the caspase cascade and the mitochondrial break-down occur in a timely ordered sequence coordinated by the genuine p53 amino terminus and suggest caspase 8 and PIG3 as key regulatory elements in this process. Oncogene (2000) 19, 4096 - 4107

Authors+Show Affiliations

Children's Cancer Research Institute, St. Anna Kinderspital, Vienna, Austria.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

10962570

Citation

Kovar, H, et al. "Characterization of Distinct Consecutive Phases in Non-genotoxic P53-induced Apoptosis of Ewing Tumor Cells and the Rate-limiting Role of Caspase 8." Oncogene, vol. 19, no. 36, 2000, pp. 4096-107.
Kovar H, Jug G, Printz D, et al. Characterization of distinct consecutive phases in non-genotoxic p53-induced apoptosis of Ewing tumor cells and the rate-limiting role of caspase 8. Oncogene. 2000;19(36):4096-107.
Kovar, H., Jug, G., Printz, D., Bartl, S., Schmid, G., & Wesierska-Gadek, J. (2000). Characterization of distinct consecutive phases in non-genotoxic p53-induced apoptosis of Ewing tumor cells and the rate-limiting role of caspase 8. Oncogene, 19(36), 4096-107.
Kovar H, et al. Characterization of Distinct Consecutive Phases in Non-genotoxic P53-induced Apoptosis of Ewing Tumor Cells and the Rate-limiting Role of Caspase 8. Oncogene. 2000 Aug 24;19(36):4096-107. PubMed PMID: 10962570.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Characterization of distinct consecutive phases in non-genotoxic p53-induced apoptosis of Ewing tumor cells and the rate-limiting role of caspase 8. AU - Kovar,H, AU - Jug,G, AU - Printz,D, AU - Bartl,S, AU - Schmid,G, AU - Wesierska-Gadek,J, PY - 2000/8/30/pubmed PY - 2000/10/7/medline PY - 2000/8/30/entrez SP - 4096 EP - 107 JF - Oncogene JO - Oncogene VL - 19 IS - 36 N2 - To dissect the p53-dependent apoptotic pathway, events following induction of temperature sensitive (ts) p53val138 were studied in a Ewing tumor cell line. Transcriptional deregulation of p53 targets first observable after 1 h at 32 degrees C preceded activation of caspases and the break-down of mitochondrial respiratory activity. Activation of caspases was first observed 4 h after p53 induction. Using peptide inhibitors we identified activation of caspase 8 upstream of caspases-9 and -3. Although the caspase 8 specific inhibitor z-IETD.fmk did not affect translocation of BAX to the mitochondrial membrane and cytochrome C release it almost completely blocked cleavage of the prototype caspase substrate PARP and DNA fragmentation while enforcing mitochondrial depolarization and production of reactive oxygene species (ROS). Activation of caspase 8 did not involve death-domain receptor signaling. Expression of BCL2 only partially suppressed caspase activation but blocked apoptosis. Replacement of the N-terminus of p53val138 by the related VP16 transactivation domain created a ts p53 with a tanscriptional activity indistinguishable from p53val138 until the time of caspase activation. However, the VP16 - p53 fusion failed to trigger caspases and subsequent induction of the ROS producing gene pig3 paralleled by complete loss of apoptotic activity. These results indicate that p53-dependent transcriptional deregulation, triggering of the caspase cascade and the mitochondrial break-down occur in a timely ordered sequence coordinated by the genuine p53 amino terminus and suggest caspase 8 and PIG3 as key regulatory elements in this process. Oncogene (2000) 19, 4096 - 4107 SN - 0950-9232 UR - https://www.unboundmedicine.com/medline/citation/10962570/Characterization_of_distinct_consecutive_phases_in_non_genotoxic_p53_induced_apoptosis_of_Ewing_tumor_cells_and_the_rate_limiting_role_of_caspase_8_ L2 - https://doi.org/10.1038/sj.onc.1203780 DB - PRIME DP - Unbound Medicine ER -