This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We propose the theory that the host response is intimately involved in the process of metastasis, and that a better understanding of the tumor-host interaction is essential if there is to be an improvement in outcomes. We have recently discovered autoantibodies in lung cancer patients that have a strong association to the non-metastatic phenotype. Based on these findings, we have formulated the hypothesis that the humoral response in some patients with cancer plays a determining role in whether or not metastasis occurs. We propose initially to investigate an autoantibody prevalent in non-metastatic patients and determine if it is protective against metastasis, and if so, by what mechanism. We have found that conditioned medium (CM) from H1568 cells (a highly metastatic human lung cancer cell line) is capable of initiating CD34+ hematopoietic progenitor cell (HPC) migration in an in vitro assay that mimics one of the initial steps in the development of the metastatic niche. Sera from patients with stage I non-recurrent or late stage metastatic adenocarcinomas were used to probe western blots of proteins from CM from this cell line in order to identify autoantibodies to proteins with possible migration promoting functions. We identified antibodies to alpha-glucosidase II in 70% of patients with non-recurrent lung cancer and in none of the patients with metastatic lung cancer. Addition of an anti-alpha-glucosidase II antibody to the CM decreased CD34+ cell migration in vitro by 31-63%. This suggests that H1568 cells secrete an extracellular form of glucosidase II that is functional on cell surface glycoproteins of CD34+ cells. We want to determine first if priming animals with conditioned medium will accelerate metastatic disease, and then determine if inhibition of glucosidase II will reduce metastasis. We will use imaging (microCT) to follow the development and progression of lung metastasis. This will allow us to use a minimal number of animals to determine differences in rates, size, and distribution of metastatic lesions. We will begin by using a well established mouse model of metastasis through tail vein injection. 1. Eight immunocompromised mice will be used. Four mice will be primed with condition medium from H1568 lung cancer cells for 3 days. Four mice will be primed with serum free medium. We will then inject all mice with approximately one million tumor cells, and the animals will be imaged two times per week for three weeks (previous studies have suggested that the metastasis will be well established by 21 days). As above we will determine if priming the animals will increase metastasis. 2. We will then plan to perform a second experiment and pre-treat 4 mice with affinity purified human anti-alpha-glucosidase II antibody at the time of CM injection to see if this blocks HPC migration (monitored from a small blood sample taken at each imaging procedure) and number or size of metastases (passive immunity). Four control mice will not receive the antibody. These two initial imaging studies will provide us with preliminary data to efficiently design future studies. As we develop a new paradigm for early detection and the process of metastasis, the capability for non-invasive imaging will become an invaluable research tool to evaluate our animal models.
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