1. Role of the Microenvironment and Feedback Signaling Loops in Stabilizing Disease States Martin Beckerman, PhD Y-12 National Security Complex Oak Ridge, TN 37831 Biomedical Science & Engineering Conference Oak Ridge National Laboratory March 18-19, 2009

2. Disease-Associated Microenvironments DiseaseTriggerCells Metabolic -T2D -Atheroscl. Lipid buildup Cholesterol buildup; Hemodynamic stresses Ad, M En, P, SM, M CancersTumor growthEp, En, F, SC, M Neurodeg. -AD -PD Misfolded Aβ Misfolded α-synuclein N, As, Mi

3. T Cell Inactivation Tumor cells avoid destruction through T cell inactivation Macrophage-derived suppressor cells disable the T cells Requires signals first from tumor cells then from the T cells M1 (inflammatory) and M2 (repair) macrophages Results in arginine depletion and ROS generation Disables the ζ-ζ chains and halts signaling

4. T Cell Inactivation

5. Myofibroblast Stabilization Fibroblasts - connective tissue cells Myofibroblast form - promotes tissue repair Associated with all stages of cancer development and metastasis Stabilized by a positive feedback loop Activates latent TGFβ through mechanical tension Promotes angiogenesis, invasiveness, and metastasis

6. Myofibroblast Stabilization

7. Bone Metastasis Bone metastasis – breast, prostate, lung tumor cells Primed tumor cell exploit osteoblast () – osteoclast () system Generates imbalance that favors tumor cell colonization Generates positive feedback involving TNFα family members RANKL and RANK TGFβ and IGF signals by osteoclasts promote colonization Enhanced by calcium, and by other physical factors

8. Bone Metastasis

9. Summary of Salient Points Disease states stabilized by positive feedback loops brought on by sustained inflammatory conditions Involves a diverse set of mediators including hypoxia, mechanical forces, ROS, TNFα, TGFβ,… Generated by dynamically changing cell populations and states of differentiation within the microenvironment Hypothesized to underlie long-term drug ineffectiveness

10. Microenvironment Modeling and Simulation Study how cell populations and differentiation states respond to drugs Explore how to shift from M2 to M1 behavior through manipulations to signaling pathways Mechanically link signaling pathways to microenvironment Explore how to break formation of disease- sustaining feedback loops Fill in gaps left by in vivo murine models, in vitro data, and drug trials Requires a sustained, systems medicine approach; tissue models and supporting databases a key component