PROJECT SUMMARY While primary, early-stage breast cancer is curable, metastatic breast cancer remains a clinically significant problem. Recent analyses of clinical samples have shown that the increased infiltration of sympathetic and sensory nerve fibers into the mammary tumors, a phenomenon known as tumor innervation, is highly correlated with metastatic potential of breast cancer. Despite recent interests in understanding breast tumor innervation, there still exists a critical gap in fundamental knowledge in the molecular and cellular mechanisms of breast tumor innervation. The goal of this project is to address this gap in knowledge by studying metabolic regulations of breast tumor innervation and subsequent effects on metastasis. A wealth of literature suggests that metabolic dysregulation could in fact be linked to tumor innervation and heightened metastatic potential. For instance, metabolic rewiring such as aerobic glycolysis and glutamine addiction of cancer cells leads to changes in the tumor microenvironment that increases secretion of neurotrophins such as nerve growth factor and brain-derived neurotrophic factor, as well as pro-axonogenic extracellular matrix components. Despite the obvious implications of blocking tumor innervation to reduce metastatic frequency, the therapeutic potential of targeting metabolic rewiring to prevent breast tumor innervation and curb metastasis has not yet been carefully evaluated. Therefore, we hypothesize that aerobic glycolysis and glutamine addiction in breast cancer promotes breast tumor innervation leading to heightened metastasis. To test our hypothesis, we will utilize our tissue-engineered 3D culture platforms that have been optimized in-house to study tumor innervation. Our platforms comprise tumor-mimetic collagen fiber organization and breast tumor microenvironment-mimetic decellularized adipose tissue matrices. Notably, our platform can be monitored longitudinally live using optical redox imaging to determine cell type-specific metabolic changes and its correlation with innervation. We will evaluate the link between metabolic rewiring in tumor cells and heightened innervation (Aim 1) and metastatic potential of breast cancer cells as a function of the amount of tumor innervation (Aim 2). Aim 3 will focus on analysis of deidentified patient samples from primary and metastatic breast tumors to unravel association among metabolic profiles, innervation, and clinical metastatic outcomes. Mechanistic insights will be gained via pharmacological inhibitions and genetic deletions of target metabolic enzymes and neurotrophin receptors. Outcomes of our research may lead to not only knowledge gain on correlations among metabolic rewiring, innervation and metastasis, but also novel strategies to curb metastatic breast cancer progression via interference on dysregulated cellular metabolism and innervation. Importantly, our platforms can be broadened to study metabolic regulations of cancer-nerve crosstalk in other types of non-neural cancers with proven malignant contributions from the nerves via tumor innervation (e.g., lung, pancreas, colorectal, head and neck, skin, etc.).

PROJECT NARRATIVE Recent clinical analyses have shown that increased infiltration of nerve fibers into breast tumors, also known as tumor innervation, is highly correlated with metastatic potential. Importantly, a wealth of literature suggests that metabolic dysregulation could in fact be linked to tumor innervation and metastasis. Therefore, the overall goal of this project is to investigate metabolic regulation of breast tumor innervation and potential impact it may have on metastasis.