Cooperative CCL2/CCR2 and HGF/MET signaling enhances breast cancer growth and invasion associated with metabolic reprogramming.

With over 60,000 cases diagnosed in women annually, ductal carcinoma in situ (DCIS) is the most common form of pre-invasive breast cancer in the US. Despite standardized therapy, under-treatment and over-treatment are prevailing concerns. By understanding the mechanisms regulating DCIS progression, we may develop tailored strategies to improve treatment. CCL2/CCR2 and HGF/MET signaling pathways are upregulated in breast cancers. Our studies indicate that these pathways cooperate to promote DCIS progression and metabolism. DCIS and IDC tissues were immunostained for CCL2 and HGF expression. DCIS.com and HCC1937 cells were analyzed for cell proliferation through PCNA immunostaining, apoptosis through cleaved caspase-3 immunostaining, and invasion through Matrigel transwell assays. AKT, AMPK, p42/44MAPK and PKC activities were analyzed in vitro through immunoblot and pharmacologic inhibition. CCL2 and HGF-mediated metabolism were analyzed by LC-MS. Glucose uptake and lactate production were measured biochemically. CCR2 and MET were targeted in breast xenografts through CCR2 knockout and treatment with Merestinib. Significant associations between CCL2 and HGF were detected in DCIS and IDC tissues. CCL2 and HGF co-treatment enhanced breast cancer cell growth, survival, and invasiveness over individual CCL2 or HGF treatment. These CCL2/HGF-mediated phenotypes were associated with metabolic changes including glycolysis and increased AKT, AMPK, p42/44MAPK and PKC signaling. CCL2/HGF-mediated glycolysis was reduced with AKT, AMPK and p42/44MAPK inhibition. CCR2 knockout combined with Merestinib treatment inhibited growth, survival, and stromal reactivity of breast xenografts more than CCR2 or MET targeting alone. CCL2/CCR2 and HGF/MET cooperate to enhance breast cancer progression and metabolic reprogramming.