Progression of DCIS to Invasive Breast Cancer through CCR2 Chemokine Signaling

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ABSTRACT About 50,000 cases of ductal carcinoma in situ (DCIS) are diagnosed in the US every year, making DCIS the most common type of non-invasive breast cancer diagnosed in women. Up to 20% of all patients will experience disease recurrence accompanied by invasive ductal carcinoma (IDC). Current cyto- and histopathological approaches do not accurately predict disease progression, resulting in patients being under-treated or over- treated for DCIS. Our long-term goals are to identify key factors that lead to IDC that will enable the development of a molecular based approach to predict the risk of IDC, and a more tailored approach to treat DCIS. The chemokine receptor CCR2 is a G Protein Coupled Receptor, which is normally expressed on macrophages and regulates chemotaxis in response to CCL2 during inflammation and cancer progression. Using a mammary intraductal injection model (MIND) to mimic DCIS formation in animals, we have challenged current paradigms on CCL2/CCR2 signaling, by demonstrating that CCL2/CCR2 signaling to breast cancer cells promotes DCIS progression to IDC. This R01 renewal project characterizes the role of metabolism and c-MET in CCL2/CCR2 mediated DCIS progression, and may identify better predictive markers for DCIS progression, with implications on reducing patient over-treatment, and provide justification for developing CCR2 as a therapeutic target to reduce under-treatment. Metabolic reprogramming is an important hallmark of cancer, but is poorly understood in early stage breast cancer. Preliminary studies indicate that CCL2/CCR2 enhancement of DCIS progression is associated with increased glycolysis and glutamine metabolism, which facilitate fatty acid synthesis. CCL2 mediated breast cancer invasiveness and metabolism may be dependent on interactions between CCR2 and c- MET receptor tyrosine kinases in breast cancer cells. We hypothesize that CCL2/CCR2 chemokine signaling in breast cancer cells enhances glucose and glutamine metabolism through c-MET dependent mechanisms to facilitate DCIS progression. Aim 1 is to determine the relevance of CCL2, CCR2, c-MET and metabolic enzyme expression to DCIS progression to invasive carcinoma using patient samples and magnetic resonance imaging/spectroscopy approaches in DCIS bearing animals. Aim 2 is to determine the functional contribution of c-MET to CCL2/CCR2 mediated breast cancer growth, survival, invasion and metabolism through modulating c- MET in breast cancer cells in vitro and in the MIND model. Mechanisms of CCR2/c-MET/SRC interactions in breast cancer cell lines will be examined through molecular and biochemical approaches. Aim 3 is to determine the biochemical and molecular mechanisms through which CCL2/CCR2 mediated metabolic changes promote breast cancer growth, survival and invasion through modulation of glycolytic, glutamine and fatty acid synthesis pathways in breast cancer cells in biochemical and cell culture assays. Protein degradation pathways that potentially regulate HKII, GLS1 and FASN expression in breast cancer cells will be examined through biochemical approaches.