Inhibition of GAPDH expression by RNA interference increases prednisolone-induced cytotoxicity. (A) mRNA levels of GAPDH in Jurkat cells as measured by qPCR. Two different shRNA sequences targeting GAPDH were used (shGAPDH-1 and -2). Expression of cells infected with nonsilencing shRNA sequences was set at 100% and relative expression levels were calculated. (B) Cell survival curves representing in vitro prednisolone responsiveness after RNA interference in cells interfered for GAPDH (, ▲) or in cells infected with a nonsilencing shRNA sequence (■). (C) mRNA levels of HIF-1α in Jurkat cells as measured by qPCR. Two different shRNA sequences targeting HIF-1α were used (sh HIF-1α-1 and -2). Expression of cells infected with nonsilencing shRNA sequences was set at 100%, and relative expression levels were calculated. (D) Cell survival curves representing in vitro prednisolone responsiveness after RNA interference in cells interfered for HIF-1α (, ▲) or in cells infected with a nonsilencing shRNA sequence (■). A representative experiment is shown; data are presented as means plus or minus SD (n = 3).