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. Author manuscript; available in PMC: 2015 Sep 12.
Published in final edited form as: Oncogene. 2014 Mar 31;34(11):1341–1353. doi: 10.1038/onc.2014.72

Figure 7.

Figure 7

Piperlongumine inhibits Stat3-mediated oncogenic functions. A. SUM159PT cells transduced with a Stat3-GFP reporter (GFP under the control of four repeats of the M67 sequences, a high affinity variant of the Stat3 binding sequence from human c-fos promoter) were injected into pre-cleared mouse (SCID/Beige) mammary gland and grown as xenografts. A single-cell suspension of xenograft-derived cells with differential expression pattern of GFP were FACS sorted into GFP+ and GFP− populations and assayed for mammosphere formation efficiency (MSFE) in absence or presence of PL. Shown are pictures of colonies from representative wells. B. Sum159PT xenograft-derived GFP+ cells were treated with increasing doses of PL and levels of pStat3 and GAPDH measured by Luminex. GAPDH-normalized pStat3 values were divided by those for DMSO cells and expressed as a percentage and shown along the Y-axis. C. MEF/GFP-Stat3α cells (expressing GFP-Stat3α in a Stat3-null background) and Stat3−/− MEFs were examined for Stat3 expression (C) and tested for the ability to grow under anchorage-independent conditions (D). E. MEF/GFP-Stat3α cells were treated with increasing doses of PL and photographed. F. The mean number of colonies from duplicate wells for each treatment were counted, divided by the mean number in DMSO-treated cells and expressed as percentage. These values were plotted as a function of Log [M] PL, and IC50 values calculated using GraphPad. G. Relative % viability (viability after any treatment ÷ viability of DMSO-treated cells × 100) was measured using MTT assays and plotted as a function of Log [M] PL, and IC50 values calculated using GraphPad.