STK11 and glioblastoma: On the other hand, when we reduced the amount of glucose in the medium (15-fold from 4.5 g/L to 0.3 g/L), we observed a significant reduction in miR-451 expression in all GBM cells tested, but not in HeLa cells, [60,62] that are known for lack of functional LKB1 due to gene methylation [62,92] suggesting that intact AMPK signaling is required for repression of miR-451 in low glucose.