Abstract IA07: Single cell functional proteomics and metabolomics: A conduit to physicochemical models of tumor biology

Abstract

Abstract Advances in single cell methods have opened up fundamentally new ways to think about biology. One new concept involves specific experiments that provide a direct and quantitative bridge between complex biological phenomena and the physico-chemical laws. To this end, we have developed microchip-based methods for measuring large panels of functional proteins and metabolites from statistical numbers of single cells. Functional proteins include secreted signaling proteins that provide measures of immune cell behaviors, and phosphorylated (activated) enzymes that reflect intracellular signaling flux and are often hyperactivated (and thus constitute drug targets) in cancers. For metabolites, we have focused on those associated with cellular energy flux. Importantly, cells sense and respond to their environments by adjusting the levels of such analytes. The following observations are the basis for connecting such measurements to the physico-chemical laws: 1. Cells are finite systems in a thermodynamic sense. This means that otherwise identical cells will have different numbers of the measured analytes. 2. A histogram of levels of the analytes versus frequency of observation across many single cells represents the fluctuations of those cells. In the maximum entropy formulation of thermodynamics, fluctuations can be used to identify the stable steady state of the cells (the state of minimum free energy), as well as constraints that prevent (constrain) the cells from reaching that steady state. 3. When many analytes are measured from the same cells, analyte-analyte correlations are extracted. If the measurements are quantitative (as are ours), then relationships between the chemical potential of a given analyte and its copy numbers is established. These to values represent cognate intensive and extensive parameters, and can allow for precise predictions for how cells respond to a weak perturbation through the Principle of Le Chatelier. They also provide an approach for distinguishing between weak and strong perturbations, since strong perturbations cause a cell-state change, while weak perturbations do not. In this talk, I will discuss provide detail on the above described experimental platforms, and describe how analyses based on these concepts can yield insight into clinically meaningful problems associated with therapy resistance in glioblastoma and melanoma. Citation Format: James R. Heath. Single cell functional proteomics and metabolomics: A conduit to physicochemical models of tumor biology. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr IA07.