The ErbB2 receptor tyrosine kinase is overexpressed in approximately 30% of breast tumor cases and its overexpression correlates with an unfavorable prognosis. A major contributor for this course of the disease is the insensitivity of these tumors toward chemotherapy. Monoclonal antibodies, inhibiting the ligand-induced activation of the receptor and… (More)
FIGURE 9. Transduction of purified peptide aptamer AII-7 has no influence on the phosphorylation of AKT activated via EGFR or IGF-IR. MCF-7 cells (A), A431 cells (B), or Renca-EGFR (C) were grown to 80% confluency and were then starved overnight. Peptide aptamers fused with a PTD were fast protein liquid chromatography purified using a histidine tag. The same batch of protein was used in Fig. 8C. The peptides were added in the medium of the cells in concentrations as indicated in each figure. After 4 h, EGF (10 ng/mL) or IGF-I (100 ng/mL) was added for 15 min as indicated. Cells were washed twice with ice-cold PBS and radioimmunoprecipitation assay extracts were prepared. Proteins were blotted and membranes were incubated with AKT, MAPK (p42/44) antibodies, or antibodies recognizing the phosphorylated form of these proteins (pAKT and pMAPK). The Flag antibody was used to detect the amount of transduced peptide aptamers in the cell lysates. A h-tubulin antibody was used to verify equal loading of the samples.