Project: Novel peptide conjugates for imaging carbonic anhydrase IX expression in living subjects
Other Key Personnel
Edward Graves, PhD; Assistant Professor of Radiation Oncology, Co-PI
Sarah Moore, PhD: Graduate Student Fellow in Cochran lab
Sandeep Apte, PhD: Postdoctoral Researcher in Graves lab
Carbonic anhydrase IX (CA IX) is a membrane-bound protein overexpressed on the surface of cancer cells in a hypoxic environment. CA IX is involved in tumor cell survival and metastasis, and increased expression correlates with poor clinical outcome; however, there are no approved therapies or imaging agents against CA IX. Monoclonal antibodies have been used to target CA IX, but their large size limits penetration throughout a poorly vascularized tumor, and their slow blood clearance limits their use as tumor imaging agents or radiotherapeutics due to high background and toxicity concerns. Small organic molecules that inhibit CA IX are available, but these compounds are highly non-specific, and can diffuse across cell membranes to bind to intracellular carbonic anhydrase isoforms abundant in healthy tissue. Here, the Cochran and Graves labs will collaborate to create novel CA-IX targeting molecules for clinical translation as diagnostic agents. In addition to generating new CA IX targeting molecules, this work will result in the development of a general technology platform to improve the biodistribution of small molecule tumor-targeting agents.
Project: Red for STED: Advanced Optical Microscope Development for Superresolution Imaging of Biological Structures
Other Key Personnel
Lana Lau (graduate student)
Almost all biological fluorescence microscopy with visible light is restricted to the diffraction limit of resolution of ~200 nm1, which is too large to resolve many processes in the cell below the organelle level, such as protein clustering, cytoskeletal structures, neural connections, ribosomes, etc. In 2008, Nature Methods awarded the Method of the Year to super-resolution microscopy, a set of imaging approaches that allow the “visualization of cellular structures smaller than can be visualized with conventional microscopy” which is poised to “revolutionize the current understanding of the workings of the cell”2. The Moerner lab is engaging in super- resolution microscopy studies3-4, one of which utilizes the Stimulated Emission Depletion (STED) approach invented by Stefan Hell5. Our current STED implementation with a blue pulsed pumping laser has a modest resolution of 80 nm, which is not sufficient to resolve fine cellular structures.
Our primary goal is to push the resolution to 20 nm with the proper choice of optimized fluorescent dyes which require a red pumping laser. We seek to establish our STED microscope as a state-of-the-art super-resolution imaging tool for elucidating the nanostructure of key biomedical systems.