Figure 1

pAkt^ser473 is elevated and phosphatase and tensin homolog lost in basal-like but not luminal-like xenografts. (A) Immunostaining of luminal-like (LL; top) and basal-like (BL; bottom) xenograft tumor sections from the vehicle control group, stained with anti-pAkt^ser473 (red) and anti-pan-Akt (green) antibodies, and secondary antibodies conjugated with near-infrared (NIR) fluorescent dyes (red channel, pAkt^ser473; green channel, pan-Akt). Negative control sections were stained with secondary antibodies alone (left two images in the panels). Tumors were isolated 3 days after the start of the treatment and 5 hours after the last supplementation of the respective drugs. All scale bars = 1 mm. (B) Quantification data from NIR immunofluorescence imaging (n = 4). The signal intensity of the total Akt immunostaining is similar in BL and LL xenografts, whereas the signal for pAkt ^ser473 is approximately fivefold higher in BL compared with LL xenografts. **P <0.0005. (C) Immunoblot analysis of the level of pAkt^ser473, total Akt and phosphatase and tensin homolog (PTEN) in lysates from two different BL and LL cancers. Level of β-actin included as a loading control. Numbers above the images and the lanes in the immunoblot refer to the individual tumor-bearing mouse. (D) Higher phosphatidylinositol 3-kinase (PI3K) signaling activity in BL xenografts was also confirmed by immunoblot analysis of pAkt^thr308 levels.