Targeting Glucose Consumption and Autophagy in Myeloma with the Novel Nucleoside Analogue 8-Aminoadenosine

Multiple myeloma, an incurable plasma cell malignancy, is characterized by altered cellular metabolism and resistance to apoptosis. Recent connections between glucose metabolism and resistance to apoptosis provide a compelling rationale for targeting metabolic changes in cancer. In this study, we have examined the ability of the purine analogue 8-aminoadenosine to acutely reduce glucose consumption by regulating localization and expression of key glucose transporters. Myeloma cells counteracted the metabolic stress by activating autophagy. Co-treatment with inhibitors of autophagy results in marked enhancement of cell death. Glucose consumption by drug-resistant myeloma cells was unaffected by 8-aminoadenosine, and accordingly, no activation of autophagy was observed. However, these cells can be sensitized to 8-aminoadenosine under glucose-limiting conditions. The prosurvival autophagic response of myeloma to nutrient deprivation or to nucleoside analogue treatment has not been described previously. This study establishes the potential of metabolic targeting as a broader means to kill and sensitize myeloma and identifies a compound that can achieve this goal.