GLUT3 promotes glucose uptake and the proliferation of mesenchymal lung tumor cells. (A) Mesenchymal (SW1573) or epithelial (H727) cells were transfected with control (ctl) siRNA, each of three different siRNAs to decrease GLUT3, or each of two siRNAs to decrease GLUT1, as indicated. One hundred forty-four hours later, live cells were counted by trypan blue exclusion (n = 3 or 4). (B) 2-Deoxy-d-[3H]glucose (DOG) incorporation was measured in SW1573 cells stably expressing ctl shRNAs or shRNAs targeting GLUT3 (in pSicoR or pLKO.1 vectors, see ‘Methods’). Data show means ± s.d. (n = 3) of glucose uptake (nmol) measured for 10 min, normalized to protein concentration. (C) SW1573 cells stably expressing ctl shRNAs or shRNAs targeting GLUT3 (in pSicoR or pLKO.1 vectors) were prepared in soft agar for anchorage-independent growth. Three weeks later, the number of colonies was determined (n = 6). (D) H727 cells, either parental or stably expressing a control (ctl) plasmid or a GLUT3 cDNA, were cultured in high or low glucose (glc) concentrations for 4 days, after which live cells were counted by trypan blue exclusion (n = 7).