Clara Y. Choi MD,PhD, Presenter: Nothing to Disclose

Ramasamy Paulmurugan PhD, Abstract Co-Author: Nothing to Disclose

Quynh-Thu Xuan Le MD, Abstract Co-Author: Nothing to Disclose

Albert C. Koong MD, PhD, Abstract Co-Author: Nothing to Disclose

Sanjiv Sam Gambhir MD, PhD, Abstract Co-Author: Consultant, Spectrum Dynamics Ltd Stockholder, Spectrum Dynamics Ltd Consultant, GlaxoSmithKline plc Scientific Advisory Board, VisualSonics Inc Stockholder, VisualSonics Inc Consultant, MediCorp Health System Speaker, Promega Corporation Consultant, Millennium Pharmaceuticals, Inc Scientific Advisory Board, Varian Medical Systems, Inc Consultant, Pathwork Diagnostics (Predicant Biosciences, Inc) Speaker, Siemens AG Consultant, Johnson & Johnson (ALZA Corporation) Scientific Advisory Board, General Electric Company Grant, General Electric Company Board of Directors, Lumera Corporation Stockholder, Lumera Corporation

Amato John Giaccia PhD, Abstract Co-Author: Nothing to Disclose

Wayne Zundel PhD, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

pVHL is the substrate binding subunit of the E3 ubiquitin ligase complex and is required for proteasomal degradation of HIF-1α under normoxia. Mutations in the VHL gene cause VHL disease, an autosomal dominant human cancer syndrome. Using the split firefly luciferase complementation based bioluminescence system, we have studied mutations found in VHL disease families and how each mutation may affect the interaction between HIF-1α and the mutant pVHL.

We have engineered HIF-1α and pVHL split firefly luciferase system in which the interaction between HIF-1α and pVHL leads to complementated based bioluminescence. The ability of each mutant VHL to bind HIF-1α was measured by co-transfecting in the split luciferase expression plasmids into mammalian cells and measuring the complementation based luciferase assay using a luminometer. Imaging studies were done using nude mice implanted with HIF-1α and pVHL split firefly luciferase expressing mammalian cells. Animals were imaged using an optical cooled charge-coupled devise camera.

Of the VHL mutants studied, P154L and F119S exhibited the lowest complementation based bioluminescence, suggesting that these mutants are significantly impaired in their ability to bind HIF-1α. L188V mutant retained the ability to complement HIF-1α level similar to WT VHL while V84L and R167Q exhibited slightly lower complementation based luciferase activities. The interaction between HIF-1α and VHL were imaged using mice. In living subjects, the in vivo bioluminescence signal produced by the complementation of HIF-1α split luciferase by the WT VHL is significantly greater than that of the F119S mutant, confirming that the VHL F119S mutant has a decreased affinity for HIF-1α.

Here, we describe a novel technique for imaging the interaction between HIF-1α and VHL mutants in living subjects. Understanding of such interactions is a key step in developing new treatments for renal cell carcinoma and chemoprevention in VHL patients.

This allows for screening of new drugs for the treatment of renal cell carcinoma and intra-tumor target validation of candidate compounds.

Choi, C, Paulmurugan, R, Le, Q, Koong, A, Gambhir, S, Giaccia, A, Zundel, W, et al, , Studying the Interaction between Von-Hippel Lindau Mutants and HIF-1a in Living Subjects Using Molecular Imaging.  Radiological Society of North America 2006 Scientific Assembly and Annual Meeting, November 26 - December 1, 2006 ,Chicago IL. http://archive.rsna.org/2006/4439230.html