on 05-01-201210:31 AM - edited on 10-15-202111:45 AM by Closed Account
Viner R, Bomgarden R, Zhang T, Major M, Zabrouskov V. Application Note 445 The DNA damage response pathway is critical to maintaining genome stability, and proteins within this pathway are commonly misregulated in cancer cells. Camptothecin, an anti-cancer drug, inhibits topoisomerase I DNA unwinding and leads to DNA damage in cells undergoing DNA replication. It has been shown that protein concentrations change in response to DNA damage and other cellular stresses through post-translational modifications, specifically phosphorylation.
Depending on the type of DNA damaging agent, phosphorylation can be rapid—reaching a maximum 2 hours after treatment—or more robust and prolonged with a maximum between 8 and 24 hours after treatment. Quantitation of the responses of different proteins or phosphorylation sites to camptothecin or other agents may help to elucidate the signaling pathways critical to the development of new anti-cancer drugs. Previous studies indicated that the Thermo Scientific LTQ Orbitrap XL mass spectrometer with an HCD cell can be successfully used to accurately and precisely quantify iTRAQ-labeled peptides. Here, we extended our efforts to use iTRAQ labeling and the LTQ Orbitrap XL equipped with an HCD cell to identify and characterize the dynamics of DNA damage response proteins in A549 cells over a period of 24 hours after treatment with camptothecin.