Selective targeted delivery of doxorubicin via conjugating to anti-CD24 antibody results in enhanced antitumor potency for hepatocellular carcinoma both in vitro and in vivo

Purpose Antibody–drug conjugates (ADCs) represent a promising therapeutic approach for clinical application. Cluster of differentiation 24 (CD24) is over-expressed in several human malignancies, especially in hepatocellular carcinoma (HCC). We aimed to develop a new class of CD24-targeted ADCs for HCC. Methods DOX was conjugated with G7mAb by a heterobifunctional cross-linker GMBS ( N -[gamma-maleimido butyryloxy] succinimide ester) and further analyzed using HPLC. The targeting specificity and endocytosis of the newly generated ADC, G7mAb–DOX, were characterized using flow cytometry assay, near-infrared fluorescence imaging and laser scanning confocal microscope. The antitumor effects were evaluated in nude mice bearing HCC xenografts. Results G7mAb–DOX with average two drug molecules per antibody was selectively captured and endocytosed by CD24 (+) tumor cells in vitro. In vivo, the ADC was proved to target tumor tissues, suppress tumor growth and prolong the survival of HCC-bearing nude mice with improved efficacy and less systemic toxicity compared with either G7mAb or DOX single-agent treatment. Conclusion These studies provide proof of concept for development of DOX-based ADCs which provide a novel approach for HCC-targeted immune therapy in clinical application.