Fig. 4.

TD19 triggers cell apoptosis through CIP2A/PP2A/pAkt signaling.

(a) TD19 exhibited limited effect on EGFR phosphorylation in MDA-MB-231 and MDA-MB-468 cells. (b) TD19 disrupted the interaction between SET and PP2Ac. (c) Analysis of PP2A activity in TD19-treated MDA-MB-468 cells. Cells were incubated with DMSO, TD19 (3 μM), forskolin (40 μM, as a positive control) or okadaic acid (20 nM, as a negative control) for 24 h. Cell lysates were assayed for PP2A activity. (d) Cells were incubated with DMSO or TD19 (3 μM) for 24 h. The cell lysates were analyzed by Western blot. (e) Cells were treated with TD19 at the indicated doses for 48 h and cell viability was assessed by MTT assay. (f) Cells were treated with TD19 at the indicated doses for 24, 30, and 36 h. Apoptotic cells were determined by flow cytometry (sub-G1 analysis of PI- stained cells). (g) MDA-MB-231 and MDA-MB-468 cells were treated with TD19 at the indicated doses for 24 h and further analyzed by Western blot (up). The results were quantified (down). (h) MDA-MB-231 and MDA-MB-468 cells were treated TD19 with 4 μM and 3 μM respectively for indicated time. Whole-cell extracts were prepared and assayed by Western blot (up). The results were quantified (down). Points, mean (N = 3); columns, mean (N = 3); bars, SD. Student's t-test, *, P < 0.05; **, P < 0.01; ***, P < 0.001.