Enhanced Glycolysis Promotes Function Of Tumor Associated Macrophages In Mouse Breast Cancer Model

Tumor associated macrophages(TAMs) represent a major part of immune cells in tumor microenvironment(TME) and play crucial roles in promoting tumor progression by secreting cytokines or enzymes that could remodel TME or enhance envision or migration capabilities of tumor cells. Given their indispensable effect on tumor, the mechanisms underlying TAMs’ tumor-promoting phenotype and function remain unclear. Glucose metabolism in tumor cells has been intensively studied; however, the status of glucose metabolism of TAMs is still unclear. In this study, we aim to identify glucose metabolism status in TAMs, and explore how glucose metabolism regulates phenotype and function of TAMs. In the begining, we isolated TAMs from 4T1 mouse breast tumor, spleen macrophages from normal mouse as a control, and performed RNA sequencing to analyze the expression pattern in glucose metabolism related genes. The results from transcriptomics showed that TAM shown up regulation of glycolysis genes pattern. Then we analyzed and found that HK’s activity was increased while IDH’s activity was decreased in mouse breast cancer moel. Furthermore, In vitro, we found that up regulation of impotent glycolysis genes including HK2, PFK-L and LDHA in mouse peritoneal macrophages (CMPM) and mouse bone marrow derived macrophages (CMBMDM) conditionally cultured with 4T1 supernatants. Glucose consumption or production of lactate and ATP were also increased in CMPM or CMBMDM. Then we monitored lactate producing rate with seahorse energy metabolism detector, and found that either CMPM or CMBMDM produced lactate faster than that of control. Moreover, inhibition of LDHA activity by oxamate ( inhibitor) also decreased glucose consumption and lactate production. Importantly, the expression of Arg1 and CD206, positively correlated with glycolysis and function of TAMs. Finally, we search the underneath mechanism and found PI3K/AKT pathway was activated in CMPM or CMBMDM. In detail it was found that p-p85 and p-AKT was upregulated at 8 hour after 4T1 supernatants stimulation. Inhibition of PI3K/AKT pathway by LY294002 (PI3K inhibitor), notably inhibited the expression of glycolysis genes and markers of TAMs, which indicated that PI3K/AKT pathway maybe involved in glycolysis of TAMs. Together, we identified that TAMs adopted glycolysis as a major way to consume glucose and glycolysis was directly contributed to the phenotype and function of TAMs, which was regulated by PI3K/AKT signaling pathway. Citation Format: Yan Liu, Wei Zhou, Wei Wang, Lipeng Bai, Huiwen He, Jian Guo, Yunping Luo. Enhanced glycolysis promotes function of tumor associated macrophages in mouse breast cancer model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4631. doi:10.1158/1538-7445.AM2017-4631