Research Project
10271568
Project 2: SUMMARY Organ colonization and survival of circulating tumor cells (CTCs) depends on a response program in tumor cells (TCs), termed mechano-adaptation, to cope with mechanical and molecular stresses on the cytoplasm and nucleus experienced during intravascular arrest and extravasation. The strength and duration of mechanical stress differs in vascular beds among organs, such as liver and skin, and further differs between individual-cell and collective organ colonization. Molecular systems implicated in the mechano-adaptation of CTCs include coordinated cell-cell adhesions, cytoskeletal contractility, protease systems and deformation or the nucleus, which cooperate to secure multistep movement into the secondary site and TC survival. We hypothesize that successful metastasis in vivo depends on an adaptive interplay between the mechanical and molecular intra- and perivascular stresses present at distant site and the coping ability of CTCs to overcome these stresses. By coordinated cell-cell adhesion, cytoskeletal contractility, deformation of the nucleus, and protease systems we predict that mechano-adaptation secures individual-cell and collective TC survival and further mediates lasting reprogramming towards growth or dormancy. Consequently, we anticipate that interfering with cell mechanical adaptation strategies will increase cell stress, support CTC death and diminish metastatic organ colonization. By combining intravital microscopy in mouse models, computational modeling (Core A) and transcriptomic and chromatin structure analyses (Core B), we will address the rate-limiting steps of single-cell and collective organ colonization of triple-negative breast cancer and melanoma cells to skin and liver. In Aim 1 we will examine the mechanisms of collective and single-cell organ colonization and metastatic outcomes, by interfering with adherens junctions (p120-catenin) and intravascular coagulation. In Aim 2, we will identify the rate-limiting steps of cytoskeletal and nuclear mechanics and the ability to remodel the vascular wall during single-cell and collective organ colonization. Targeted interference with CD44-mediated adhesion to perivascular substrate, actomyosin contractility, nuclear deformability by lamin A/C expression variation and the ability to reorganize the basement membrane will be performed. In Aim 3, we will identify the molecular responses underlying stress-induced mechano- adaptation and associated effects on nuclear chromatin conformation, using transcriptomic and ultrastructural analyses combined with computational modeling. Identified key pathways implicated in mediating mechano- adaptation and TC survival, cell cycle arrest (dormancy) and outgrowth will be inhibited by combined molecular interference to limit TC survival and both single-cell and collective metastasis. This project will deliver an integrated view on cell migration, molecular reprogramming, fate decisions, and reveal potential intervention points to enhance tumor cell elimination in transit.
