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    Home > Research & Grants > Grants Program > Research Grants > Research Grants Awarded > Abstract
    Awarded Grants
    Molecular Basis of Bone Metastasis in Breast Cancer

    Scientific Abstract:
    The metastatic spread of breast tumor cells from their site of origin in the breast to distant organs is responsible in large part for the morbidity and mortality of the disease. Advances in functional genomics and proteomics now provide powerful approaches for identifying genes responsible for the spread of tumor cells to distant organs and, once identified, for determining roles that these genes play in the metastatic process. This project involves establishment of a novel system for identifying and studying genes involved in metastasis of mammary tumor cells to bone and other organs. The model will utilize a well-characterized mouse mammary tumor cell line, known to have the capacity to metastasize to bone, liver, lungs and brain when introduced orthotopically into syngeneic BALB/c mice. The line has been modified with a luciferase reporter gene and drug resistance genes to facilitate analysis of in vivo metastasis and isolation of metastasized cells from organ tissues. A FLP recombinase site has been introduced into the line to allow targeted integration of genes for over-expression experiments and stably-expressed RNAi constructs for gene silencing experiments. Variants of the engineered line will be isolated from bone, liver, lung and brain metastases. Those that display altered metastasis to these sites relative to the parental line will be subjected to microarray analysis to identify genes potentially involved in the observed specificity. Over-expression and gene silencing experiments will then be used to verify involvement of such genes in metastasis. The project is expected to result in identification of several genes that will serve as new targets for therapeutic inhibition of metastasis to bone, liver, lungs and/or brain. "Knockdown" and over-expressing cell lines produced from these studies will serve as valuable tools in future experiments for investigating the function of identified genes in processes related to organ-selective metastasis and the model itself will provide an effective means of testing drugs for therapeutic effects on breast tumor metastasis.

    Lay Abstract:
    Recent advances in genomics and proteomics are providing new and more effective approaches for uncovering genes involved in breast cancer and other diseases. Once identified, such genes provide targets for improved diagnosis, prognosis and treatment. The goal of this project is to establish a model system in mice for rapid and effective identification and analysis of genes involved in the selective spread of breast tumor cells to distant organs. The project is focused on metastasis to bone, liver, lungs and brain, sites to which metastasis occurs in breast cancer patients with advanced disease. Biophotonic imaging, a recently developed technique that allows non-invasive visualization and quantitation of tumor growth and metastatic spread in living animals, will be used to follow tumor growth and metastasis of genetically engineered tumor cells following implantation into mammary tissue. A well-characterized metastatic mouse mammary tumor cell line will be used as the model cell line. The genome of these cells has been engineered by incorporation of a luciferase reporter gene and drug resistance genes to allow imaging and facilitate isolation of the cells from metastases, and by construction of a specialized site into which DNA for over-expression and RNAi gene silencing experiments can be targeted by the investigator. The engineered cells will be implanted in mice and cells that metastasize to bone and other organs will be isolated from metastases and cloned. These cells will have undergone genetic changes that facilitate metastasis to the organs in which they are found. Cell lines that display increased ability to metastasize to these organs will be compared to the parental cells and other cell lines using gene expression analysis. The analysis will reveal differences in expression of genes that correlate with the observed differences in metastasis. The involvement of genes in organ-selective metastasis will then be verified by over-expressing or inhibiting their expression and showing that the appropriate effects on metastasis are produced by the modification. These cell lines will provide valuable tools to further analyze the roles that these genes play in the metastatic process. The project will produce new target genes for diagnosis, prognosis and treatment of breast cancer and a new, more effective mouse model for assay and analysis of metastasis to organs affected by the disease.