Lactate-Modulated Induction of THBS-1 Activates Transforming Growth Factor (TGF)-beta2 and Migration of Glioma Cells In Vitro
Figure 3
Glioma cell migration is reduced after competitive inhibition of LDH-A.
Sodium oxamate was used for competitive inhibition of LDH. LDH activity was determined using the cytotox assay (Promega, Germany). Treatment with increasing doses of sodium oxamate (5 mM-75 mM) significantly reduces LDH activity 24 hours after treatment (HTZ, 349 p < 0.01** for 25mM, 50 mM and 75 mM sodium oxamate; U87, p < 0.001*** for 25mM, 50 mM and 75 mM sodium oxamate, fibroblasts, p < 0.01** for 10 mM and p < 0.001*** for 25mM, 50 mM and 75 mM sodium oxamate). HTZ 349 and U87 showed significantly higher LDH activity compared to fibroblasts (HTZ-349 p < 0.01##, U87 p < 0.001###) (A). Lactate levels were measured in cell culture supernatants 24 hours after treatment with increasing doses of sodium oxamate (10 mM-75 mM). Treatment with sodium oxamate leads to a dose- (B) and time-dependent reduction (C) of extracellular lactate levels. Treatment with 25 mM and 50 mM sodium oxamate significantly reduces HTZ-349 (D) and U87 (E) glioma cell migration starting 24 hours after treatment (HTZ, 349 p < 0.001*** at 24 h and 32 h for 25 and 50 mM sodium oxamate; U87, p < 0.05* at 24 h, p< 0.01** at 32 h for 50 mM sodium oxamate). (F) Boyden chamber assay showing similar effects as in (D) and (E) (U87, p< 0.001***; HTZ-349, p < 0.001***). The Y-axis indicates the number of migrated cells. Results were normalized to control.