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For modulation of AMPKα activity, MDSC were treated with 5-Aminoimidazole-4-carboxamide 1-β-D-ribofuranoside (Aica-R, 200 μM, Millipore), Metformin (10 mM, Millipore), or Dorsomorphin-Compound C (CC, 5 μM, Cayman). Moreover, LLC-bearing mice received CC (15 mg/kg, i.t.), Metformin (150 mg/kg, i.p.), or Aica-R (0.5 mg/kg, i.p.) 9 days post-tumor injection and continued to be treated daily until tumor endpoint. For in vitro studies inhibiting Nos2, we used L-NG-Monomethylarginine (L-NMMA, 500 μM, Cayman) and Lysine-dihydrochloride (L-NIL, 300 μM, Cayman); whereas for in vivo assays, LLC-bearing mice were treated daily starting at day 0 of tumor injection with 20 mg/kg L-NIL (Cayman, i.p.). Human IL-6, mouse granulocyte-monocyte colony stimulating factor (GM-CSF) and mouse granulocyte-colony stimulating factor (G-CSF) were from Gemini. Human GM-CSF was from eBioscience. Thioglycolate broth from Sigma-Aldrich was prepared at 4% in water, autoclaved, and stored in dark for 2 weeks before i.p. injection. To test the role of GM-CSF in TES-treated MDSC, we utilized blocking antibodies against mouse-GM-CSF (5 μg/ml, Clone MP1022E9) and/or mouse-GM-CSF receptor α (1 μg/ml, Clone 698423, R&D systems). Rat IgG2a isotype (Clone 2A3, BioXcell) was used as control.