Fig. 4

25KbPEI mediated activation of ERK/mTOR-eIF4E signaling pathways increases IFN-γ translation. A Immunoblot analysis conducted to detect phosphorylation of eIF4E in NK-92MI cells treated with 25KbPEI for the indicated times (left). The bands were quantified using Image Lab, and the ratio of p-eIF4E/total eIF4E is presented (right). Statistical analysis was performed using one-way ANOVA with Dunnett’s multiple comparisons test (vs. 0 h). B Amount of IFN-γ in NK-92MI cells treated with 25KbPEI in the presence or absence of CGP57380 (right). NK-92MI cells were pretreated for 1 h with CGP57380 (10 μM) and then incubated with 25KbPEI for 12 h. Cytoplasmic IFN-γ was quantified by flow cytometry. C Effect of 25KbPEI on phosphorylation of 4E-BP1 in NK-92MI cells. NK cells were treated with 25KbPEI for 3 h and p-4E-BP1 was quantified by flow cytometry. D Amount of IFN-γ in NK-92MI cells treated with 25KbPEI in the presence or absence of 4EGI-1. NK-92MI cells were pretreated for 3 h with 4EGI-1 (50 μM) and then incubated with 25KbPEI for 12 h. Cytoplasmic IFN-γ was quantified by flow cytometry. Statistical analysis was performed using Student's t-test (vs. C_NK), and one-way ANOVA with Tukey’s multiple comparisons test. All experiments were conducted at least three times. *P < 0.05; **P < 0.01; ***P < 0.001, and ****P < 0.0001. E Schematic diagram showing 25KbPEI-mediated ERK/mTOR signaling, and the role of the downstream factor eIF4E in IFN-γ production by NK-92MI cells treated with 25KbPEI