Wednesday, May 21, 2025
5/21/2025
Unraveling the Connection: How Metabolism Shapes Mammalian Persister Survival - UNRAVELING THE CONNECTION: HOW METABOLISM SHAPES MAMMALIAN PERSISTER SURVIVAL Summary Our overall goal in this research project is to evaluate the role of metabolism in persister cell survival in mammalian cell populations. Persister cells are defined as a small fraction of quiescent cells in a tumor bulk population that exhibit temporary tolerance to drugs. These cells are an important health concern because they are thought to underlie the proclivity of recurrent tumors to relapse, and they serve as a reservoir from which drug-resistant mutants can emerge. Due to their transient state, persisters possess the capacity to revert to a state of growth and produce drug-sensitive daughter cells; however, their physiological properties underlying entry into and exit from this quiescent state remain unclear. The central hypothesis of this proposal is that persisters have a transient metabolic state characterized by increased oxidative phosphorylation and decreased anabolic activities. Our previous studies indicate that transient metabolic rewiring in persisters is largely induced by chemotherapeutic agents, which may result from the inhibition of cell growth. In our 1st Aim, we will verify our hypothesis through the use of persister assays, proteomics, metabolomics, redox sensors, phenotype microarrays, and a range of mammalian cell types and chemotherapeutic agents. By utilizing fluorescence microscopy and fluorescent reporters, we will uncover the metabolic dynamics of persister cells through the examination of individual cell trajectories during and after drug treatment. In our 2nd Aim, we plan to uncover the active metabolic pathways and their significance in persisters through a combination of experimental data and mathematical models. Our mathematical approach will involve utilizing optimization programming with various objective functions to assign weight values for each metabolic pathway. The models will take into account the topological properties of the metabolic network, as well as constraints such as reaction rates, thermodynamics, and other regulatory mechanisms. By comparing the results of multiple models, we will identify the common or unique crucial features. Our hypothesis is that a metabolic pathway that is consistently identified as significant through different models will play a crucial role in the survival of persister cells. Our hypothesis will be tested by disrupting the targeted pathways through genetic and chemical means. The proposed research program is expected to have a substantial impact for the following reasons: (i) There is an ongoing debate about whether dormant, quiescent, tolerant, and persister cells in tumors are the same population or related to tumor stem cells. Despite this uncertainty, the existence of a small fraction of phenotypes that survive initial treatments is undisputed, and this should raise significant concerns within the medical community. (ii) Our approach uniquely combines experimental results with computational models to identify unknown biochemical pathways driving persister cell metabolism. (iii) The proposed research will have a broader impact as the methods developed here will be applicable to persister cells in diverse mammalian and microbial organisms.
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