OUR PATHWAY TO MEDICINE
Cells of all types regularly encounter mechanical force during interactions with their environment. These forces provide queues to the cell through mechanically-linked signal transduction (mechanosensing) pathways that instruct cell behavior. The development and function of cells such as stem cells and immune cells within 3-dimensional multicellular tissues are critically dependent upon the ability of these cells to sense force and geometry at the sub-micron and nanometer level. Those processes are some of the best examples of force-mediated changes in cell behavior. Our center’s goal is to understand the pathways used by cells to sense force and geometry, and incorporate mechanical design principles into the control of cell behavior for the development of clinically useful therapeutics.
Our Clinical Collaborations
Our Center has developed a powerful toolbox for capturing micro- and nano-scale features of the extracellular environment in precisely engineered structures. Significant work over the past two years has applied new software, hardware and cell biological tools to define the adhesome, to measure force continuously in different rigidity environments, to follow the force-sensing pathways, to assess mechanisms of matrix force generation, and to understand the role of mechanics in immune synapse formation. In addition, we have developed probes for many important components in the mechanosensing pathways. Although we could continue to study many different mechanical signaling pathways and the integration of those signals in an abstract context, we feel that we can use the same approaches to manipulate and understand differentiation pathways that are important for clinical applications. These techniques will be applied to understanding how mechanical and biomolecular factors drive high-level cellular functions in the context of the immune system (collaboration with Drs. June and Milone - UPenn Medical School), ultimately directed toward two clinical applications of these cells. These projects take advantage of the rich toolbox, along with our Center’s strengths in cell biology, signaling networks, biomechanics and clinical medicine.
Immunotherapy of Cancer (Drs. June and Milone - UPenn Medical School)
Our long-term goal in this area is to develop a new generation of clinically relevant T cell culture systems for adoptive immunotherapy of cancer and infectious disease. The ability of adoptively transferred T cells to mediate therapeutic effects is now well documented in the settings of chronic viral infections and cancer. However, reproducibly harnessing this activity requires that several technical barriers be solved. Our central hypothesis is that it is possible to develop nanostructured culture surfaces to program T cell differentiation along desired pathways. A related hypothesis is that infusion of engineered autologous T cells that have been cultured on micropatterned/nanostructured culture systems that mimic the natural presentation of stimulatory signals will have enhanced engraftment and effector function in humanized mice and ultimately humans. Taking advantage of the expertise and capabilities of our center, we plan to test the functionality of T cells that have been cultured on nanofabricated surfaces using a variety of in vitro and in vivo models as described in the recently approved Pathways to Medicine Clinical Collaborator Supplement. The joining of Drs. Milone and June with our NDC provides a solid foundation for our meeting the “Pathway to Medicine” goals of the NIH Roadmap Nanomedicine Initiative. This project grew from an intra-NDC collaboration between the Kam and Dustin labs, and it is based upon using microcontact printing to approximate physiological patterns of co-stimulation, control forces that develop in the immunological synapse and optimize T cell stimulation. Our previous studies have demonstrated that controlling the microscale organization of signaling complexes in the immune synapses modulates cell signaling and cytokine production in T cells. The goal of the next two years is to extend this result to control over longer-term cellular functions, most notably the differentiation of T cells into effector, memory, or regulatory classes. These studies will include molecules representing a wider range of signaling pathways, and additional geometries, as inspired from observation of T cell interactions with natural antigen presenting cells, protein-presenting lipid bilayers, or cells presenting new classes of engineered ligands. In addition, the role that substrate rigidity has on T cell activation and later differentiation will be tested, using the fabrication toolbox of our Center. In the next two years, we forsee the completion of animal-scale engraftment studies with human CD4+ and CD8+ T cells, for subsequent use in preclinical settings. The clinical collaborator project provides an excellent opportunity to further the aims of our center in translating the basic findings of various NDC investigators into technologies that are useful in the treatment of human disease.
We anticipate that the results of these studies will contribute to more rationally designed and improved T cell culture systems that will be useful in human clinical trials involving both unmodified and gene-modified T cells that are currently underway at the collaborator’s institution.