Mammary tumor development induces perturbation of liver glucose metabolism with inflammation and fibrosis.

Abstract

Cancer cells rely on glycolysis and lactic fermentation for ATP production, inducing an abnormal glucose uptake in tumors. However, it is largely unknown whether the increased tumor glucose consumption affects overall body glucose homeostasis including perturbation of the liver glucose production pathways. The effect of mammary tumor development on liver metabolism pathway was examined by using a mouse model based on FVB/N wild-type (WT-SD) and FVB/N-Tg(MMTV-PyVT)634Mul/J mice (Tg-SD), who develop spontaneous mammary tumors. Blood and livers were analyzed for metabolic changes, by measuring histological staining, signaling and insulin sensitivity. Tg-SD mice developed mammary tumors with an average weight of 6g, and cancer development increased total food intake without impacting body weight gain. Tumor development did not affect blood glycemia and lactate levels but increased insulin and HOMA-IR index (p=0.06). In the liver, Tg-SD mice with tumors exhibited a decrease in glycogen content, and an increase in gluconeogenesis gene expression, as G6pc, Pgc1α and Foxo1 (p<0.05), as well as Pepck and Ldha (p<0.01). Moreover, the phosphorylation of AMPK and AKT was significantly decreased (respectively (p<0.01 and p<0.05)). Surprisingly, liver fibrosis was markedly increased in Tg mice (p<0.05) alongside elevated inflammatory gene expression, such as IL1β (p<0.01) or IL6 (p<0.05). Here we found that the development of non-metastatic mammary tumors using the MMTV-PyMT mouse model disrupts liver function through the development of inflammation, fibrosis and metabolic perturbation, including an increase in glucose production and insulin resistance. Finally, these observations unravel a previously unknown metabolic crosstalk between the tumors and the liver.