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. Author manuscript; available in PMC: 2014 Oct 7.
Published in final edited form as: Cancer Res. 2009 Feb 24;69(5):1836–1843. doi: 10.1158/0008-5472.CAN-08-4103

Figure 5. Role of eIF2α in the effects of PIs on HIF-1α expression and protein synthesis.

Figure 5

A. Knockdown of eIF2α rescued HIF-1α expression. LNCaP-Pro5 cells were transfected with a siRNA construct specific for eIF2α or a non-targeted control siRNA. Transfected cells were incubated with 100nM bortezomib, 10nM NPI-0052 or 5μM thapsigargin for 8h under hypoxic conditions. Levels of HIF-1α and eIF2α were examined by immunoblotting and actin served as a loading control. B. Effects of PIs on eIF2α and protein translation in MEFs. MEFs were incubated with 100nM bortezomib, 100nM NPI-0052 or 10μM thapsigargin for 4h. Phosphorylated eIF2α(Ser51) and total eIF2α levels were measured by immunoblotting. Protein synthesis was measured by [L-4,5-3H]Leucine incorporation. Data shown are mean±S.E. C. Effects of PIs on HIF-1α in MEFs. MEFs were treated as above for 12h under hypoxic conditions. Levels of HIF-1α and total eIF2α were measured by immunoblotting.