ABSTRACT
Why do seemingly identical cells respond differently to a drug? To address this, we studied the dynamics and variability of the protein response of human cancer cells to a chemotherapy drug, camptothecin. We present a dynamic-proteomics approach that measures the levels and locations of nearly 1000 different endogenously tagged proteins in individual living cells at high temporal resolution. All cells show rapid translocation of proteins specific to the drug mechanism, including the drug target (topoisomerase-1), and slower, wide-ranging temporal waves of protein degradation and accumulation. However, the cells differ in the behavior of a subset of proteins. We identify proteins whose dynamics differ widely between cells, in a way that corresponds to the outcomes-cell death or survival. This opens the way to understanding molecular responses to drugs in individual cells.
Subject(s)
Antineoplastic Agents, Phytogenic/pharmacology , Camptothecin/pharmacology , DNA Topoisomerases, Type I/metabolism , Lung Neoplasms/metabolism , Lung Neoplasms/pathology , Proteins/metabolism , Proteome/metabolism , Cell Death , Cell Division/drug effects , Cell Line, Tumor , Cell Nucleolus/drug effects , Cell Nucleolus/metabolism , Cell Nucleus/drug effects , Cell Nucleus/metabolism , Cell Survival/drug effects , Cytoplasm/drug effects , Cytoplasm/metabolism , DEAD-box RNA Helicases/metabolism , DNA Damage , Enzyme Inhibitors/pharmacology , Fluorescence , Humans , Luminescent Proteins/metabolism , Metabolic Networks and Pathways , Oxidative Stress , Proteomics , Replication Protein C/metabolism , Topoisomerase I InhibitorsABSTRACT
The ALL-1 gene is directly involved in 5-10% of acute lymphoblastic leukemias (ALLs) and acute myeloid leukemias (AMLs) by fusion to other genes or through internal rearrangements. DNA microarrays were used to determine expression profiles of ALLs and AMLs with ALL-1 rearrangements. These profiles distinguish those tumors from other ALLs and AMLs. The expression patterns of ALL-1-associated tumors, in particular ALLs, involve oncogenes, tumor suppressors, antiapoptotic genes, drug-resistance genes, etc., and correlate with the aggressive nature of the tumors. The genes whose expression differentiates between ALLs with and without ALL-1 rearrangement were further divided into several groups, enabling separation of ALL-1-associated ALLs into two subclasses. One of the groups included 43 genes that exhibited expression profiles closely linked to ALLs with ALL-1 rearrangements. Further, there were evident differences between the expression profiles of AMLs in which ALL-1 had undergone fusion to other genes and AMLs with partial duplication of ALL-1. The extensive analysis described here pinpointed genes that might have a direct role in pathogenesis.
