Activation of PI3K/AKT pathway is required for promotion of vIL-6-induced tumorigenesis by Tat in nude mice.

<p>(<b>A</b>) Tat augments vIL-6-induced phosphorylation of AKT and GSK-3β in nude mice. Phosphorylation AKT and GSK-3β in tumor tissues from 4E3 and T/V cells transduced by Tat and Mock in nude mice were analyzed by Western blot. (<b>B</b>) Plot of the volume of the tumors. 4E3 cells were transfected by the AKT-DN and its control plasmid pSRα for 24 hours and followed by Tat or Mock transduction for another 24 hours. Cells were injected s.c. into the left flank of the mice. The animals were monitored every day for the appearance of tumors until 30 days. Tumor size was estimated by two-dimensional caliper measurement. The results are expressed as the mean ± SD (n = 5). *<i>P</i><.05 and **<i>P</i><.01 for Student’s <i>t</i>-test versus Tat+AKT groups, respectively. ^△<i>P</i><.05 and ^△△<i>P</i><.01 for Student’s <i>t</i>-test versus Mock+pSRα groups, respectively. <i>ns</i>, not significant, <i>t</i>-test. (<b>C</b>) Column diagram of average tumor weight. Tumor-bearing mice were killed at day 30 after injections, and tumors were removed and weighed. Data reflect the mean ± SD. (<b>D</b>) Inhibition of AKT activity abolished the promoted effect of Tat on phosphorylation of GSK-3β by vIL-6. 4E3 cells were treated as in (B). The phosphorylation level of GSK-3β in tumor tissues of nude mice was analyzed by Western blot. (<b>E</b>) Plot of the volume of the tumors. 4E3 cells transduced with Tat or Mock were injected s.c. into mice for allograft formation. The mice received the treatments by intraperitoneal injection of LY294002 (the detailed procedure seen in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0053145#s2" target="_blank">Methods</a>). The results are expressed as the mean ± SD (n = 5). *<i>P</i><.05 and **<i>P</i><.01 for Student’s <i>t</i>-test versus Tat+LY294002 groups, respectively. ^△<i>P</i><.05 for Student’s <i>t</i>-test versus Mock+DMSO groups, respectively. (<b>F</b>) Column diagram of average tumor weight. Tumor-bearing mice were killed at day 40 after injections, and tumors were removed (Top) and weighed. Data reflect the mean ± SD (Bottom).