Cancer Chemotherapy and Pharmacology

, Volume 57, Issue 3, pp 357–367

Bcl-2-mediated potentiation of neocarzinostatin-induced apoptosis: requirement for caspase-3, sulfhydryl groups, and cleavable Bcl-2

  • Zhiping Mi
  • Borah Hong
  • Zeljka Korade Mirnics
  • Yulia Y. Tyurina
  • Valerian E. Kagan
  • Ye Liang
  • Nina Felice Schor
Original Article

DOI: 10.1007/s00280-005-0054-z

Cite this article as:
Mi, Z., Hong, B., Mirnics, Z.K. et al. Cancer Chemother Pharmacol (2006) 57: 357. doi:10.1007/s00280-005-0054-z

Abstract

Overexpression of antiapoptotic Bcl-2 family members is thought to contribute to chemotherapeutic resistance of neural crest tumors. Paradoxical potentiation by Bcl-2 of apoptosis induced by the antineoplastic prodrug, neocarzinostatin (NCS), has been observed in PC12 pheochromocytoma cells. Prior studies have indicated that the cleavage of Bcl-2 to its proapoptotic counterpart mediated by caspase-3 is responsible for this potentiation of apoptosis. This has led to the hypothesis that induction of caspase-3 expression in bcl-2-transfected, caspase-3-deficient MCF-7 cells, will result in Bcl-2 cleavage and Bcl-2-dependent potentiation of NCS-induced apoptosis. These studies have further led to the hypothesis that both cleavable Bcl-2 and sulfhydryl groups are required for the activity of caspase-3 in this regard. As hypothesized, co-transfection of bcl-2-transfected MCF-7 cells with a caspase-3 expression construct results in cleavage of Bcl-2 and potentiation of dose-dependent, NCS-mediated cell death. Furthermore, PC12 cells transfected with an expression construct for cleavage-resistant Bcl-2 demonstrated attenuated potentiation of apoptosis relative to their counterparts transfected with wild-type bcl-2. Finally, irreversible oxidative titration of sulfhydryl groups resulted in concentration-dependent attenuation of apoptosis in PC12 cells, along with prevention of caspase-3 activation and Bcl-2 cleavage. These results definitively demonstrate the requirement for caspase-3, cleavable Bcl-2, and available sulfhydryl groups (separate from those required for NCS activation) in potentiation of NCS-induced apoptosis by Bcl-2.

Keywords

Caspase-3 Apoptosis Chemotherapeutic agent Enediyne Reduced glutathione 

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Zhiping Mi
    • 1
    • 2
  • Borah Hong
    • 1
    • 2
  • Zeljka Korade Mirnics
    • 1
    • 2
  • Yulia Y. Tyurina
    • 3
  • Valerian E. Kagan
    • 3
  • Ye Liang
    • 1
    • 2
  • Nina Felice Schor
    • 1
    • 2
  1. 1.Division of Child Neurology, Pediatric Center for NeuroscienceChildren’s Hospital of Pittsburgh of UPMCPittsburghUSA
  2. 2.Department of PediatricsUniversity of PittsburghPittsburghUSA
  3. 3.Department of Environmental and Occupational HealthUniversity of PittsburghPittsburghUSA