Combined Docetaxel/Pictilisib-Loaded mPEGylated Nanocarriers with Dual HER2 Targeting Antibodies for Synergistic Chemotherapy of Breast Cancer

Wei-Jie Cheng,1,* Shyr-Yi Lin,2,3,* Kuo-Hsiang Chuang,4,5,* Michael Chen,4 Hsiu-O Ho,1 Ling-Chun Chen,6 Chien-Ming Hsieh,1 Ming-Thau Sheu1 1School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei, Taiwan; 2Division of Gastroenterology, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan; 3Department of General Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; 4Graduate Institute of Pharmacognosy, Taipei Medical University, Taipei, Taiwan; 5PhD Program in Clinical Drug Development of Chinese Herbal Medicine, Taipei Medical University, Taipei, Taiwan; 6Department of Biotechnology and Pharmaceutical Technology, Yuanpei University of Medical Technology, Hsinchu, Taiwan*These authors contributed equally to this workCorrespondence: Chien-Ming Hsieh; Ming-Thau Sheu, Email cmhsieh@tmu.edu.tw; mingsheu@tmu.edu.twIntroduction: Approximately 15%~30% of breast cancers have gene amplification or overexpression of the human epidermal growth factor receptor 2 (HER2), resulting in the chemotherapy resistance, a more-aggressive phenotype and poor prognosis.Methods: We propose a strategy of nanocarriers co-loaded with docetaxel (DTX) and pictilisib (PIC) at a synergistic ratio and non-covalently bound with dual anti-HER2 epitopes bispecific antibodies (BsAbs: anti-HER2-IV/methoxy-polyethylene glycol (mPEG) and anti-HER2-II/methoxy-PEG) for synergistic targeting to overcome the therapeutic dilemmas of the resistance for HER2-targetable chemodrugs. DTX/PIC-loaded nanocarriers (D/P_NCs) were prepared with single emulsion methods and characterized using dynamic light scattering analysis, and the drug content was assayed by high-performance liquid chromatographic method. The integrity and function of BsABs were evaluated using sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) and enzyme-linked immunosorbent assay (ELISA). The in vitro cell studies and in vivo breast t