HER2:HER3 heterodimerization and its inhibition by compound 9 observed by PLA. Concentration-dependent inhibition of HER2:HER3 heterodimers was observed. Control-SKBR-3 cells showing only HER2:HER3 heterodimerization as red spots. CP-A control compound did not inhibit HER2:HER3 heterodimerization. At a sub-optimum dose of compound 9 (0.4μM), HER2:HER3 heterodimerization was inhibited to a lesser extent. At an optimum dose of compound 9 (0.8 μM), HER2:HER3 heterodimerization was significantly inhibited. Reproduced with permission from Kanthala, S., Banappagari, S., Gokhale, A., Liu, Y. Y., Xin, G., Zhao, Y., & Jois, S. (2015). Novel peptidomimetics for inhibition of HER2:HER3 heterodimerization in HER2-positive breast cancer. Chemical Biology & Drug Design, 85, 702–714. https://doi.org/10.1111/cbdd.12453. Copyright (2014) John Wiley and Sons.