Research


Breast cancer metastasis is regulated by the effects of signals originating in the environment of cancer cells and within breast cancer cells. 
We develop innovative approaches to for imaging molecular and cellular events in living systems.

We aim to understand how intracellular and extracellular signals impact the ability of cancer cells to:
  • leave the primary tumor, 
  • travel throughout the body, 
  • localize to distant sites, and 
  • remain dormant or 
  • initiate formation of a metastasis
Cell behaviors, such as migration, and cell states, such as epithelial to mesenchymal transition (EMT) and cancer stem cells, both contribute to cancer metastasis. We have several projects investigating aspects of these processes. Our expertise in optical imaging of living systems and the engineering of novel optical imaging reporters enables us to visualize key aspect of cancer signaling and cellular behavior.

Breast cancer metastasis and recurrence
Most breast cancer mortality is related to metastatic breast cancer, which can occur early in the disease process or many years after the initial diagnosis and treatment. Cells that spread from the primary site are thought to reside in the bone marrow, among other sites, and be protected from therapy by the cellular environment there.  They may lie dormant or slowly divide and die to maintain a steady silent population for many years. Under the right conditions, these cells may resume more rapid growth and initiate a recurrence of the disease which is difficult to control.  More information for patients about the process of cancer metastasis can be found at the National Cancer Institute here



Fluorescent and bioluminescent reporters we develop, combined with advanced instrumentation,  enables us to literally "see" molecular and cellular events in living cells, engineered tissues, and animal models. 

Fluorescent proteins are used in the Luker lab to accomplish a wide range of goals in visualizing molecular and cellular events in living systems.  This image shows co-localization of a protein of interest in cancer cell metabolism, fused to a red fluorescent protein, with mitochondria, marked by a green fluorescent protein.  Using this approach we can track mitochondrial dynamics and morphology in live cells.

Two-Photon In Vivo Fluorescence imaging 
The Luker lab performs fluorescence imaging in live cells, 3-dimensional tissue models, and animal models using a state-of -the-art Olympus FVMPE-RS multiphoton scanning microscope. The image below shows a 3-dimensional scan of a breast cancer tumor in a mouse showing cells with red nuclei and cyan reporter construct in a tumor in mice.
Fluorescence Lifetime imaging In Vivo 
Our FVMPE-RS is equipped with custom-designed equipment from ISS for imaging fluorescence lifetimes.  The lifetime of fluorescence is the time that elapses between excitation and emission from a fluorophore, and is dependent on the structure and environment of the fluorophore.  Fluorescence lifetime imaging can be used for imaging metabolism, fluorescence resonance energy transfer (FRET) between a fluorophore and its surroundings, and other biochemical features such as pH that impact fluorophore energy states.  A major benefit of fluorescence lifetime imaging for tissue imaging is that it remains relatively constant when imaging at different tissue depths.  The figure below from  our work shows an example of lifetime imaging  used to detect signal from a FRET-based reporter, in this case reporting activation of Caspase 3.
Bioluminescence In Vivo imaging 
The Luker lab has a long history of innovation and excellence in bioluminescence imaging. We develop bioluminescent methods to detect biochemical and cellular events using multispectral bioluminescence imaging and protein fragment complementation assays.  Our primary methods of imaging is with a IVIS imaging instruments Ivis Lumina and Spectrum from Perkin-Elmer.  Our bioluminescent reporters employ luciferases from a variety of organisms, including fireflies, click beetles, the copepod Gaussia princeps, and the deep sea shrimp Oplophorus gracilirostrus.  From our early work in 2004 developing firefly luciferase complementation, we have particularly focused on using bioluminescence to detect and quantify protein interactions in living systems, as in the figure below which measures recruitment of arrestin to a G-protein coupled receptors CXCR4 and CXCR7 for computational modeling.