Figure 1.

Neomycin inhibits nuclear translocation of ¹²⁵I-angiogenin in (A) and angiogenin-induced proliferation of (B) HUVE cells. (A) HUVE cells were cultured at 50,000 cells per 35-mm dish and were treated with neomycin at the concentrations indicated. ¹²⁵I-angiogenin was added to a final concentration of 1 μg/ml and incubated at 37°C for 30 min. Nuclear fractions were isolated and radioactivities were determined. In a typical experiment, nuclear ¹²⁵I-angiogenin amounts in the presence of 0, 10, 20, 50, 100, 200, and 500 μM neomycin were 3,090 ± 260, 1,790 ± 50, 1,630 ± 70, 1,440 ± 300, 1,230 ± 60, 1,090 ± 50, and 420 ± 100 cpm, respectively. Data shown are percentages relative to the control. (B) HUVE cells were cultured at 40,000 cells per 35-mm dish and stimulated with 1 μg/ml angiogenin in the absence or presence of neomycin at the concentrations indicated at 37°C for 48 hr. In a representative experiment, cell numbers in the absence of angiogenin and neomycin or in the presence of 100 μM neomycin were 39,400 ± 300, and 39,200 ± 800, respectively. Cell numbers after stimulation with 1 μg/ml angiogenin in the presence of 0, 5, 10, 25, 50, 100, and 200 μM neomycin, were 53,200 ± 200, 46,500 ± 400, 46,000 ± 600, 43,800 ± 1600, 39,300 ± 800, 39,500 ± 1100, and 35,200 ± 1000, respectively. Increase of cell number stimulated by angiogenin at each neomycin concentration was calculated and compared with that in the absence of neomycin, which was defined as 100% proliferative activity.