Figure 5

Glutamine and glucose metabolism is increased in antiestrogen resistant cells. A-B, LCC9 cells were significantly more sensitive to (A) compound-968, an inhibitor of GLS/GAC, and to (B) STF-31, an inhibitor of GLUT-1. Bars represent the mean ± SE of relative number (normalized to vehicle control) for a single representative experiment performed in sextuplicate. ANOVA, p ≤ 0.001; *p < 0.05 for LCC9 versus LCC1 for indicated concentrations. C, Cells were treated with compound-968 (20 μM), STF-31 (5 μM), ICI (100 nM), or the indicated combinations for 48 h. Bars represent the mean ± SE of relative cell number (normalized to vehicle controls) for a single representative experiment performed in sextuplicate. ANOVA, p < 0.001; *p < 0.05 for LCC9 versus LCC1 for indicated treatments. D, Knockdown of GLS levels with siRNA in LCC9 cells showed significant decrease in cell number within 24 h compared with that in LCC1 cells. ANOVA, p = 0.03; *p ≤ 0.05 for LCC9 GLS siRNA compared with LCC1 GLS siRNA. E, Western blot showing decreased levels of GLS in both cell lines; actin was used as a protein loading control. F, Right, LCC9 ells were treated with 10058-F4 (25 μM), or vehicle for 48 h; left, transfected with MYC or control siRNA for 48 h. Knockdown of MYC increased GLS/GAC levels and decreased GLUL levels. G, siRNA mediated MYC knockdown showed increase in GLS and a decrease in GLUL levels in LCC2 and LY2 cells.