Specific protein 1 depletion attenuates glucose uptake and proliferation of human glioma cells by regulating GLUT3 expression.

It has been reported previously that the expression of glucose transporter member 3 (GLUT3) is increased in malignant glioma cells compared with normal glial cells. However, the regulating mechanism that causes this phenomenon remains unknown. The present study investigated the regulating role of transcription factor specific protein 1 (Sp1) in GLUT3 expression in a human glioma cell line. In the present study, Sp1 was identified to directly bind to the GLUT3 5'-untranslated region in human glioma U251 cells. Small interfering RNA- and the Sp1-inhibitor mithramycin A-mediated Sp1 knockdown experiments revealed that Sp1 depletion decreased glucose uptake and inhibited cell growth and invasion of U251 cells by downregulating GLUT3 expression. Therefore Sp1 is an important positive regulator for the expression of GLUT3 in human glioma cells, and may explain the overexpression of GLUT3 in U251 cells. These results suggest that Sp1 may have a role in glioma treatment.