Supramolecular antibody-drug conjugates for combined antibody therapy and photothermal therapy targeting HER2-positive cancers.

Antibody therapy of anti-HER2 monoclonal antibody (mAb) has been an important strategy in treating HER2-positive cancers. However, the efficacy is restricted by many factors, including the level of HER2 expressed by tumor cells and antibody resistance. To overcome these and boost the efficacy, a novel nanoparticle (NP) was constructed in this study for combined antibody therapy of antibody and photothermal therapy (PTT). This novel NP was assembled from 1-pyrenecarboxylic acid (PCA) functionalized anti-HER2 mAb and indocyanine green (ICG), a photothermal transduction agents (PTA), by non-covalent interactions, which was named as Anti-HER2 mAb-pyrene-indocyanine green (H-P-I). Notably, the constructed H-P-I NP not only maintained the affinity and cytotoxicity of anti-HER2 mAb, but also exhibited high photothermal conversion efficiency mediated by ICG. Both in vitro and in vivo assessments confirmed that compared with monotherapy of antibody or ICG, H-P-I demonstrated preferable efficacy in treating HER2-positive cancers. Further biochemistry analysis and pathological analysis ensured the biosafety of H-P-I administration. Taked together, this study proposes a feasible method for constructing tumor-targeted nano PTA based on anti-HER2 mAb through supramolecular self-assembly strategy, achieving synergistic antibody photothermal anticancer treatment, which has the potential to be a promising candidate for combination therapy of HER2-positive cancers.