Nitric oxide (NO) has a wide range of potential applications in tumor therapy. However, a targeted delivery system for NO donors has remained elusive, creating a bottleneck that limits its druggability. The antibody-drug conjugate (ADC) is a targeted drug delivery system composed of an antibody linked to an active cytotoxic drug. This design may compensate for the weak targeting ability and various biological functions of the NO donor. In this study, we designed the NO donor HL-2, which had a targeted, cleaved disulfide bond and an attachable maleimide terminal. We conjugated HL-2 with an antibody that targeted CD24 through a thioether bond to generate an ADC-like immunoconjugate, antibody-nitric oxide conjugate (ANC), which we named HN-01. HN-01 showed efficient internalization and significantly increased the release of NO in hepatic carcinoma cells in vitro. HN-01 induced apoptosis of tumor cells and suppressed tumor growth in hepatic carcinomabearing nude mice through antibody-dependent co-toxicity; HN-01 also increased NO levels in tumor cells. Collectively, this study expands the concept of ADC and provides an innovative NO donor and ANC to address current challenges in targeted delivery of NO. This new inspiration for an ANC design can also be used in future studies for other molecules with intracellular targets.Significance: This study is the first to expand the concept of ADC with an antibody-nitric oxide conjugate that suppresses hepatic carcinoma in vitro and in vivo.
Interferon-α (IFNα) has multiple antitumor effects including direct antitumor toxicity and the ability to potently stimulate both innate and adaptive immunity. However, its clinical applications in the treatment of malignancies have been limited because of short half-life and serious adverse reactions when attempting to deliver therapeutically effective doses. To address these issues, we fused IFNα2a to the anti-vascular endothelial growth factor and receptor 2 (VEGFR2) antibody JZA00 with the goal of targeting it to the tumor microenvironment where it can stimulate the antitumor immune response. The fusion protein, JZA01, is effective against colorectal cancer by inhibiting angiogenesis, exhibiting direct cytotoxicity, and activating the antitumor immune response. Although JZA01 exhibited reduced IFNα2 activity compared with native IFNα2, VEGFR2 targeting permitted efficient antiproliferative, proapoptotic, antiangiogenesis, and immune-stimulating effects against the colorectal tumors HCT-116 and SW620. JZA01 showed efficacy in NOD-SCID mice-bearing established HCT-116 tumors. In conclusion, this study describes an antitumor immunotherapy that is highly promising for the treatment of colorectal cancer.
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