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. Author manuscript; available in PMC: 2016 Jun 1.
Published in final edited form as: Chem Biol Drug Des. 2014 Nov 6;85(6):702–714. doi: 10.1111/cbdd.12453

Figure 3.

Figure 3

A) Inhibition of heterodimerization of HER2:HER3 in HER2, HER3 transfected U2OS cells by compound 9 at different concentrations using enzyme fragment complementation assay (DiscoveRx). Dose-response curve for inhibition of HER2:HER3 heterodimerization by 9 in the presence of 0.3 μM NRG1 (triangles). Control compound (CP) in the presence of 0.3 μM NRG-1 (filled squares).

B) HER2:HER3 heterodimerization and its inhibition by compound 9 observed by PLA. Concentration-dependent inhibition of HER2:HER3 heterodimers was observed. SKBR-3 cells showing only HER2:HER3 heterodimerization as red spots. A control compound (CP) did not inhibit HER2:HER3 heterodimerization. At a sub-optimum dose of compound 9 (0.4 μM), HER2:HER3 heterodimerization was inhibited to a lesser extent. At optimum dose of compound 9 (0.8 μM), HER2:HER3 heterodimerization was significantly inhibited.

C) Effect of compound 9 on phosphorylation of HER2 kinase domain. SKBR-3 cells that overexpress HER2 protein upon treatment with compound 9 (1 μM). Compound 5 and lapatinib (L) (0.07 μM) and control compound (CP) are shown for comparison. The visualization of GAPDH was used to ensure equal sample loading in each lane. Phosphorylation was detected using p-HER2 antibody. Total HER2 protein is also shown.