Targeting energy metabolism of cancer cells: Combined administration of NCL-240 and 2-DG
Cancer cells increase their metabolism to produce the energy and biomolecules necessary for growth and proliferation. Thus, energy metabolism pathways may serve as targets for anti-cancer therapy. NCL-240 is a second generation anti-cancer drug belonging to the PITenins class of PI3K-Akt inhibitors. Our analysis suggested that NCL-240 caused disruptions in mitochondrial oxidative phosphorylation and up-regulated glycolysis, as evidenced by the loss of NMR peaks for the amino acid products derived from the TCA cycle along with presence of only lactate peaks and the loss of glucose peaks. NCL-240 was combined with 2-deoxy-D-glucose (2-DG) in early proof-of-concept studies on multiple cell lines. 2-DG enhanced cell death response to NCL-240 administration, with cytotoxicity results similar to those under hypoglycemic conditions. In further studies, NCL-240 encapsulated in phosphatidylcholine/cholesterol liposomes was combined with freely dissolved 2-DG. Cell cycle analysis of sensitive and resistant strains of A2780 cells treated with combinations of NCL-240/2-DG pointed to a G0/G1 phase arrest for 80–90% of the total, indicating an inability to grow and divide. Cytotoxicity studies with in vitro cancer cell monolayer models confirmed the results of cell cycle analysis. Significant improvements in cytotoxicity with combination treatments over control and individual treatments were seen in multiple cell lines. NCI/ADR-RES cancer cell spheroids further demonstrated the effectiveness of a NCL-240/2-DG combination.