Regulation of glucose transport by interleukin-3 in growth factor-dependent and oncogene-transformed bone...

Growth factors maintain cell viability and promote cell growth by stimulating glucose transport into cells and by progressing cells through the cell cycle. In the short term, effects on glucose transport involve transporter activation, while in the longer term increased gene expression is involved. This study aimed to investigate growth factor regulation of glucose transport in an interleukin (IL)-3-dependent bone marrow-derived cell line and its oncogene-transformed counterparts. 32D clone 3 (32Dcl3) cells and cells transfected with temperature-sensitive (ts) ras and abl oncogenes, were treated with and without IL-3 and their ability to take up 2-deoxy-D-glucose compared. Transformed cells, which are not dependent on IL-3 for growth at the permissive temperature of 32 degrees C, exhibited a two- to six-fold higher proliferative response, enhanced tyrosine kinase activity and c-myc expression than control cells optimally stimulated with IL-3. Compared with control 32Dcl3 cells, 2-deoxy-D-glucose uptake was also 36-76% higher in transformed cells. The increased glucose uptake in transformed cells was consistent with 2.5-fold higher affinity of the glucose transporters for glucose. IL-3 stimulated glucose uptake in both control and oncogene-transformed cells. With control and ras-transformed cells, enhanced glucose uptake in response to IL-3 was associated with increased affinity of glucose transporters for glucose but with abl-transformed cells, no significant affinity changes were observed. IL-3 also increased glucose transporter expression in both control and oncogene-transformed cells, suggesting that increased transporter expression as well as changes in transporter affinity for glucose can affect glucose uptake.