No abstract

IL-4 has a number of well-established functions in immune cells including proliferation, and survival of lymphocytes, polarization of macrophages to the pro-tumor M2 tumor associated macrophage phenotype. Another role of IL-4 signaling is induction of metabolic changes in immune cells including increased glycolysis in B-lymphocytes, and increased expression of arginase 1 with a switch to fatty acid oxidation in macrophages. However, the effects of IL-4 signaling in tumor cells that express IL-4 receptor is not well understood. Previous work from our lab has shown that loss of IL-4 receptor (IL-4R) significantly abrogates metastasis in experimental metastasis models in mice. Thus, we wondered whether changes in metabolism downstream of IL-4 receptor activation may contribute to metastatic phenotypes. Since altered metabolic pathways have been shown to regulate the epigenetic state of cancer cells, we are pursuing histone modifications as a mechanism for the connection between altered metabolism and increased metastatic capability in IL-4R expressing breast cancer cells. MDA-MB-231 and BT549 triple negative breast cancer cells were treated with IL-4 for 2,4,6, and 8 days. Samples of media were assayed for glutamine and glucose consumption, as well as lactate and glutamate secretion. IL-4 decreased consumption of glucose and glutamine, yet concomitantly increased the release of lactate and glutamate. These data suggest that IL-4 alters the utilization of glucose and glutamine in cancer cells. To study potential links to epigenetic regulation cells were treated for 18, or 48 hours with IL-4 before biochemical fractionation was performed in order to obtain nuclear and cytosolic lysates. The nuclear fractions were assessed for histone acetyltransferase (HAT) activity using commercially available assays, and showed that IL-4 increased the activity of histone acetyltransferases. We also performed pull down of acetylated lysine residue from the nuclear fractions of IL-4 treated cells. The cells were then assessed for abundance of acetylated histone 3. In addition, we used western blotting to measure the abundance of specific histone modifications such as histone 3 lysine 9 acetylation and histone 3 lysine 27 acetylation. Overall, histone acetyltransferase activity and levels of histone acetylation were increased by IL-4. Additionally, we found that IL4 increases the acetylation of histone 3 lysine 9. In order to determine the effects of IL-4 signaling on metabolism in vivo we have initiated PET imaging studies in humanized mice that underwent tail vein injections of BT549 cell lines. These mice were treated with MDNA413, an antagonist of IL-4 signaling, and are being assessed for uptake of glucose and glutamine. Together these suggest that IL-4 alters the metabolism and epigenetic state of cancer cells and may be a viable target for therapy in metastatic breast cancer. Citation Format: Demond Williams, Adam Miranda, Chilesi Uririri, Barbara Fingleton. IL4 receptor mediated metabolic changes contribute to histone acetylation leading to metastatic progression in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1201.