Abstract #3176: Activation of macrophages by the glycolytic inhibitor 2-deoxy-D-glucose (2-DG): Implications for tumor therapy
Authors: Abdullah Farooque, Saurabh Singh, Amit Verma, Farhat Afrin, Jawahar Adhikari, Bilikere Dwarakanath
Journal: Cancer Research (2009)

Tumor response to many anticancer therapies is partly contributed by the host tumor interactions. Our earlier studies have suggested that alterations in host-tumor interactions may also contribute to the radiosensitization of Ehrlich ascites tumors (EAT) by the glycolytic inhibitor, 2-deoxy-D-glucose (2-DG), besides the direct effects on tumor cells. Time dependent increase in IFN-\#947; levels observed following administration of 2-DG indicated activation of macrophages during in vivo radiosensitization. Therefore, it was considered worthwhile to investigate the effects of 2-DG on macrophagic cell systems (peritoneal macrophages and established cell lines) in vitro. Peritoneal macrophages were obtained as the adherent fraction of cells collected from peritoneal fluid. RAW 264.7 and J774.1 were maintained as monolayer cultures. 2-DG (5 mM; equimolar to the glucose concentration) treatment was given in HBSS just before irradiation (2 Gy; gamma-rays) and kept for 2 h post irradiation, then replaced with fresh medium. Cell proliferation, cell death and viability were assessed by flow cytometric DNA analysis and MTT assay respectively. Oxidative burst was measured in terms of ROS generation by flow cytometry using DCFH-DA dye. Microscopy and light scatter analysis (flow cytometry) were performed to study the changes in cytoskeleton architecture. Functional status was assessed in terms of MHC class II, CD80 and CD86 expression by flow cytometry. The radiation induced toxicity (loss of metabolic viability and fraction of degenerating cells revealed by the flow cytometric DNA analysis) increased with time after irradiation and was essentially similar in all the three cell systems. 2-DG neither induced significant cytotoxicity nor enhanced radiation-induced cell death in peritoneal macrophages and the non-tumorigenic macrophage cell line (RAW 264.7). However, a significant level of death (~30%) was evident in tumorigenic J774.1 cells as early as 8 hr and increased further with time. Decrease in radiation induced ROS levels was evident in 2-DG treated peritoneal macrophages and RAW 264.7 (un-irradiated and irradiated), might be correlated with their survival, which was accompanied by alterations in the cytoskeletal architecture indicated by enhanced side scatter (flow cytometry) and extended arborizations (microscopy). Increase in MHC class II, CD80 and CD86 expression was observed in peritoneal macrophages and RAW 264.7 cells suggestive of immune stimulation. Results obtained so far suggest that 2-DG does not compromise the survival of macrophages (peritoneal and RAW 264.7), but may induce certain alterations in structure (increase in size and arborization) and function (increased expression of MHC class II, CD80, CD86) that may stimulate the immune system contributing to the enhanced tumor regression as observed with the combination therapy (2-DG + radiation) earlier in in vivo  Citation Information: In: Proc Am Assoc Cancer Res; 2009 Apr 18-22; Denver, CO. Philadelphia (PA): AACR; 2009. Abstract nr 3176.