Breast Cancer Metastasis and Recurrence
Breast cancer metastasis is regulated by the effects of signals originating in the environment of cancer cells and within breast cancer cells. 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.
Myelofibrosis (MF) is a hematologic neoplasm arising as a primary disease or secondary to other blood malignancies. Both primary and secondary MF develop progressive fibrosis of bone marrow, displacing normal hematopoietic cells to other organs and disrupting normal production of mature blood cells. Activation of JAK2 signaling in hematopoietic stem cells commonly causes MF, and ruxolitinib, a drug targeting this pathway, is the preferred treatment for many patients. However, current measures of disease status in MF do not necessarily predict response to treatment with ruxolitinib or other drugs. Bone marrow biopsies are invasive and prone to sampling error, while measurements of spleen volume only indirectly reflect status of bone marrow. We are working toward the goal of developing an imaging biomarker for treatment response in MF.
Advanced Imaging Modalities
Two-Photon In Vivo Fluorescence imaging
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. 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 to the right shows the activation of two kinases by KTRs in a mouse mammary fat pad tumor from our recent work.
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. The figure to the right from our work on PISD shows an example of how we use bioluminescence imaging to quantify both primary tumor growth and metastatic spread in migratory vs non migratory cells.
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 to the right from our work shows an example of lifetime imaging used to measure the use of NADH for glycolytic or oxidative metabolism.