ARNT and central nervous system cancer: To determine whether suppression of p70S6K1 expression due to miR-128 overexpression affects HIF-1 expression in glioma, we found that HIF-1α but not HIF-1β protein levels were inhibited in U87 and U251 cells stably expressing miR-128 when compared to cells stably expressing miR-SCR (Figure 4A).