Background: Poly (amidoamine) dendrimers (PAMAMs) are widely used in drug delivery systems and gene transfection as drug carriers. They also exert several biological effects like modulating gene expression, particularly EGFR (ErbB1) signaling pathway, which raises the question of whether these polymers can also inhibit the phosphorylation of HER2 (ErbB2) in breast cancer. However, this area hasn’t been investigated before. Methods: In this study, we evaluated the anticancer effects of different generations and surface chemistries of PAMAMs on HER2 positive breast cancer cells (SkBr3 and ZR-75 cell lines). Cell viability and morphological changes were evaluated upon treatment with PAMAMs. In addition, their effect on colony formation in soft agar was assessed. Additionally, western blot was performed to understand the underlying mechanisms of action. Results: PAMAMs anticancer effects were found to follow a specific trend, as they were more significant in cationic polymers and in higher generations. Cationic PAMAMs reduced cell viability of HER2 positive breast cancer cells up to 5.1% in SkBr3 and to 28% in ZR75 (p<0.001), in a dose and time-dependent manner. Cationic polymers also resulted in changing the morphology in the examined cell lines, as well as inhibiting colony formation in soft agar compared to controls (p<0.001). The mechanism of action was found to be mediated by inhibiting the phosphorylation of erbB2 and JNK1/2/3. Conclusion: These anticancer effects of PAMAM dendrimers make them promising molecules, which can add benefit to current anti-HER2 treatments and be employed successfully in different biomedical applications.
Trastuzumab-grafted PAMAM dendrimers for the selective delivery of anticancer drugs to HER2-positive breast cancer
