Sorting and characterization of mechanically heterogeneous cell populations based on cellular contractility - Project Summary
Cellular contractility plays a critical role in both development and disease. Recent evidence suggests that even
within a cell population derived from the same source, vast heterogeneity exists in terms of cellular contractility.
Dysregulation of spatiotemporally organized cellular contractility often results in developmental defects. In
invasive diseases like cancer which are often highly contractile, the existence of a weakly contractile
subpopulation is receiving increasing attention. Adherent cells are known for their ability to sense and
dynamically adapt to their local microenvironment. Hence, the heterogeneity in mechanical phenotype may be a
result of genetic heterogeneity or cellular plasticity and mechanical adaptation. Mechanomedicines or mechano-
based therapies that target specific physical cellular and tissue interactions, including abnormal cellular
contractility, in diseases like cancer, fibrosis, and cardiovascular disease, as well as aging, are emerging and
hold great potential. While mechanical heterogeneity and plasticity are known to contribute to resistance to
therapies that target a specific molecular pathway, it is not clear whether a change in mechanical phenotype
predicts disease outcome or if mechanical adaption happens as a result of disease progression. This project
proposes to phenotypically sort adherent cells into subpopulations with distinct contractile phenotypes and use
these sorted subpopulations to test the hypothesis that the initial contractile phenotype and heterogeneity
determine the disease outcome against the alternative hypothesis that mechanical adaptation to the local
microenvironment and phenotypical switching contribute to disease progression regardless of the initial
mechanical heterogeneity. Cancer metastasis will be used as the main biological model for hypothesis testing.
In Aim 1, the engineering approach for cell sorting based on cellular contractility will be optimized. Fluorescence-
activated cell sorting (FACS) will be coupled with an engineered high throughput cell contractility screening
platform, automated microscopy, and photoactivation and fluorescent labeling of cells for cell separation. In Aim
2, the sorted contractile subpopulations will be used to test the main biological hypothesis in vitro and in vivo
against the alternative hypothesis. Engineered systems mimicking the environmental conditions in cancer
progression will be designed to characterize the migration, proliferation, survival, and metabolism of the
subpopulations, as well as their mechanical adaptation. The metastatic potential of these subpopulations and
their mechanical adaptations at various stages along the metastatic cascade will be examined in a mouse tumor
model. The innovative aspect of this proposal is the concept to sort by cellular contractility with the goal of
uncovering the role of initial mechanical phenotype in the progression of diseases like cancer and in development.
This project will use the novel engineered cell sorting approach to dissect the respective roles of mechanical
heterogeneity and adaptability in disease progression, thus laying the foundation for future work to identify the
key molecular pathways to precisely target for the development of mechanomedicine.
