Cisplatin reprogramming of protein phosphorylation

Abstract

ABSTRACTCisplatin is a DNA-targeting chemotherapeutic. We have utilized a forward chemical genetics strategy to map cisplatin-damaged genes (CDGs) in A549 human lung cancer cells. Importantly, we found that cisplatin targets 77% of protein kinase genes and 96% of protein phosphatase genes in the human genome, suggesting that cisplatin can reprogram protein phosphorylation genome-wide. Further, we profiled the differentially expressed proteins (DEPs) and differentially phosphorylated proteins (DPPs) in NCCIT human testicular cancer cells subjected to cisplatin treatment. We demonstrated that ca.75% of downregulated proteins are encoded by CDGs, which caused the changes in the expression of a series of protein kinases and protein phosphates, leading to significant changes in the phosphorylation level of >600 proteins in NCCIT cells, and evidencing the proteome-wide reprograming of protein phosphorylation by cisplatin. More importantly, the reprogrammed protein phosphorylation activated the G2/M DNA damage checkpoint regulation and ATM signalling pathways, causing cell cycle arrest at G2/M phase and allowing the cell apoptosis/death via cisplatin inhibition of protein synthesis.