Effect of Inhibition of GLUT1 Expression and Autophagy Modulation on the Growth and Migration of Laryngeal Carcinoma Stem Cells under Hypoxic and Low-Glucose Conditions

Abstract

Background: Enhanced glucose uptake and autophagy are means by which cells adapt to stressful microenvironments. We investigated the roles of glucose transporter-1 (GLUT-1) and autophagy in laryngeal carcinoma stem cells under hypoxic and low-glucose conditions.Methods: CD133+ Tu212 laryngeal carcinoma stem cells were purified by magnetic-activated cell sorting and subjected to hypoxic and/or low-glucose conditions. Proliferation was evaluated using a cell-counting kit and a clone-formation assay, and migration was evaluated through a Transwell assay. Autophagy was assessed via transmission electron microscopy. GLUT-1 and beclin-1 expression were silenced using an shRNA and autophagy was manipulated using rapamycin, 3-MA, or chloroquine. Gene expression levels were evaluated by quantitative reverse transcription-polymerase chain reaction and protein concentrations were assessing via Western blotting.Results: Compared to CD133– stem cells, CD133+ cells showed increased proliferation and migration, and reduced apoptosis, under hypoxic or low-glucose conditions. They also showed increased expression of GLUT-1 and autophagy markers. Finally, GLUT-1 knockdown or autophagy inhibition reduced their proliferation and migration.Conclusions: Enhanced glucose uptake and autophagy maintain the functions of CD133+ laryngeal carcinoma stem cells under hypoxic and low-glucose conditions.