Abstracts

Lanthanides have unique luminescence properties with sharp emission bands and long luminescence lifetimes. Lanmodulin, (LanM) is a newly discovered protein that binds to lanthanides in the picomolar range, making it ideal as a reagent in the development of imaging technologies. To image the cancerous tissues that are well discerned from the rest of the body, the contrast agent must preferentially concentrate in the cancerous tissue. This can be achieved using tumor specific targeting moieties. We have used lanmodulin along with a tumor-specific targeting moiety as a tool for cancer imaging. Specifically, we have designed a diagnostic test for HER2⁺ breast cancer by employing a human epidermal group factor receptor 2 (HER2)-specific antibody mimetic fused to lanmodulin as the imaging reagent that targets and binds the HER2 receptors, which are overexpressed in HER2⁺ breast cancer. For this purpose, we prepared a novel fusion protein, DARPin/LanM, by genetically fusing the gene for the HER2-specific designed ankyrin repeat protein (DARPin) to the gene for lanmodulin. HER2 negative and positive breast cancer cell lines were studied to assess the targeting ability of the DARPin/LanM reagent and its toxicity. We envision that our newly developed reagent has the potential to be translated into a series of nanomedicine diagnostic tools and find applications both in in vitro diagnostics and in vivo imaging technologies.