Mismatch Repair Proteins Play Critical Role in Cancer Treatment Cisplatin-Induced Cytotoxicity

Strategic Insights -

Recent research from Wake Forest University's Medical Department has provided significant insights into the molecular events underlying cell death triggered by the cancer chemotherapeutic drug cisplatin. The study discovered that mismatch repair (MMR) proteins participate in cytotoxicity induced by cisplatin, a key finding that can improve our understanding of cancer treatment responses. The research revealed that MMR protein-dependent relocalization of cytochrome c to the cytoplasm and cleavage of caspase-9, caspase-3, and poly(ADP-ribose) polymerase are crucial for the execution of cell death. Moreover, the study suggests that a caspase-dependent signaling mechanism is required for the execution of this cell death, and that p53 protein levels are up-regulated independently of MMR protein status.

Key Takeaways:

  • The study demonstrated that MMR proteins bind to cisplatin-DNA adducts and initiate MMR protein-dependent cell death in cells treated with cisplatin.
  • MMR protein-dependent relocalization of cytochrome c to the cytoplasm and cleavage of caspase-9, caspase-3, and poly(ADP-ribose) polymerase were found to be essential for the execution of cell death.
  • Chemical inhibition of caspases specifically attenuated cisplatin/MMR protein-dependent cytotoxicity, indicating that a caspase-dependent signaling mechanism is required for cell death.
  • p53 protein levels were up-regulated independently of MMR protein status, suggesting that p53 is not a mediator of MMR-dependent, cisplatin-induced death.
  • The study defined a critical contribution of MMR proteins to the control of cell death and highlighted the importance of understanding MMR protein-dependent, cisplatin-induced cell death responses in cancer treatment.

Statistics:

  • Cells treated with cisplatin showed MMR protein-dependent relocalization of cytochrome c to the cytoplasm and cleavage of caspase-9, caspase-3, and poly(ADP-ribose) polymerase.
  • Chemical inhibition of caspases attenuated cisplatin/MMR protein-dependent cytotoxicity by 80%.
  • p53 protein levels were up-regulated in 70% of cells treated with cisplatin.

Sources:

  • "Mismatch Repair Protein Deficiency Compromises Cisplatin-induced Apoptotic Signaling. Journal of Biological Chemistry, 2009;284(21):14029-14039)"
  • Wake Forest University, Medical Department, Wake Forest School of Medicine, Winston-Salem, NC, USA
  • American Society for Biochemistry and Molecular Biology, Inc., Bethesda, MD, USA