Metabolic alterations are established as a hallmark of cancer. Such hallmark changes in cancer metabolism are characterized by reprogramming of energy-producing pathways and increases in the generation of biosynthetic intermediates to meet the needs of rapidly proliferating tumor cells. Various metabolic phenotypes such as aerobic glycolysis, increased glutamine consumption, and lipolysis have also been associated with the process of metastasis. However, in addition to the energy and biosynthetic alterations, a number of secondary functions of enzymes and metabolites are emerging that specifically contribute to metastasis. Here, we describe atypical intracellular roles of metabolic enzymes, extracellular functions of metabolic enzymes, roles of metabolites as signaling molecules, and epigenetic regulation mediated by altered metabolism, all of which can affect metastatic progression. We highlight how some of these mechanisms are already being exploited for therapeutic purposes, and discuss how others show similar potential.

No abstract

No abstract

Breast cancer is the leading cause of cancer mortality in women. The breast cancer microenvironment supplies immune signals that influence tumor growth and metastatic behavior. The cytokine, Interleukin-4 (IL4), promotes increased survival, proliferation and invasion upon stimulation of the type II IL4 receptor alpha (IL4Rα) which is aberrantly expressed on epithelial cancer cells. Previously, we have shown that metastatic mouse mammary cancer cells have a strong dependence on IL4 signaling for colonization of metastatic sites in the lung and liver. Additionally, these cells uptake more glucose when treated with IL4 in vitro. Here, we assessed the importance of glucose consumption on pro-tumorigenic phenotypes induced by IL4/IL4Rα. In 4T1 cells, IL4/IL4Rα signaling increased protein expression of the glucose transporter, Glut1. IL4/IL4Rα activation also increased global glycosylation of Glut1. In human metastatic breast cancer cells (MDA-MB-231 and BT549), Crispr-mediated knockout (KO) of Glut1 significantly reduced glucose consumption when assayed by 2-NBDG uptake, a fluorescently labelled glucose analog. Additionally, Glut1 KO reversed the proliferative effects of IL4/IL4Rα stimulation on human cancer cells in vitro. Our data suggest that IL4-induced Glut1 expression supports the increased metabolic activity necessary for cancer cell proliferation. Targeting the IL4/IL4Rα signaling axis could potentially be a therapeutic strategy to impede tumor-associated metabolism and reduce tumor burden at primary and metastatic sites. Citation Format: Ebony Hargrove-Wiley, Daniel Valent, Demond Williams, Wendy Bindeman, Barbara Fingleton. IL4 receptor-induced proliferation is mediated via Glut1 activity in metastatic breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2446.

Breast-to-brain metastasis is a devastating disease complication for which there are currently few treatment options. Among breast cancer subtypes, patients with triple-negative breast cancer (TNBC) and HER2+ breast cancer experience elevated rates of brain metastasis. The cytokines IL4 and IL13 are overexpressed by many human solid tumors. Both are associated with invasive and metastatic phenotypes; IL13 is additionally consequential in primary brain tumors. These cytokines signal through type I (IL4 only) and type II (IL4/IL13) IL4 receptors (IL4R). Importantly, expression of type II IL4R correlates with poor patient prognosis in basal-like (i.e., triple-negative) breast cancer, and HER2+ tumors display elevated type II IL4R expression. Our laboratory has shown that genetic loss of IL4R signaling in tumor cells attenuates lung and liver metastasis in mice. Additionally, we recently identified a role for IL4R signaling in modulating glycosylation in tumor cells. We hypothesize that IL4R signaling influences TNBC brain metastasis at least in part via modulating glycosylation. In a pilot mouse study, pharmacological blockade of IL4R after intracardiac injection of syngeneic TNBC cells resulted in attenuation of brain metastatic growth and circulating tumor cell burden. We have also observed significant changes in the expression of a sialyltransferase (ST8SIA1) that has been implicated in primary brain tumors, as well as in the abundance of several sialic acid-containing protein species in breast cancer cells following treatment with IL4 or IL13. Further, IL4 stimulation increases the overall glycosylation of several proteins of interest, including a glucose transporter and a glutamine transporter, without altering gene expression. Overall, our data suggest that type II IL4R signaling promotes metastasis, potentially through a mechanism involving protein glycosylation. Blockade of this receptor may be a useful therapeutic approach for patients with breast cancer brain metastases. Citation Format: Wendy Bindeman, Demond Williams, Ebony Hargrove-Wiley, Barbara Fingleton. Investigating the role of type II IL4 receptor in breast cancer brain metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2401.