IRS-1 Regulates Inflammatory Cell Recruitment in Lung Cancer



 DESCRIPTION (provided by applicant): Lung cancer is the leading cause of cancer deaths worldwide, accounting for ~160,000 lives each year in the US alone. Making matters worse, five-year survival rates remains a dismal ~15%, highlighting the need for new and effective therapies. One approach to treat lung cancers is to optimize the function of the host immune system to fight tumors. In many cases, cancer cells are able to manipulate host immune cell function to the benefit of the tumor. The key proteins that regulate the signaling pathways cancer cells use to skew immune cell function remain poorly defined. In order to restore immune function in cancer, we must first identify the exact mechanisms that cancer cells use to recruit and manipulate immune cells. We have identified the signaling adaptor protein, insulin receptor substrate-1 (IRS-1) as a key entity that limits the ability of cancer cells to manipulate host immune responses. IRS-1 functions to homeostatically regulate the IL-22 signaling pathway in cancer cells. In its absence, enhanced JAK/STAT activity results, causing increased production of immune cell recruiting molecules (cytokines), which promotes tumor-associated inflammation. Using a variety of mechanisms, this tumor-associated inflammation promotes lung tumor growth and invasiveness. The purpose of this study will be to determine exactly how IRS-1 suppresses the ability of cancer cells to produce cytokines, and to identify key steps in these pathways that would represent novel therapeutic targets.