Cancer cell-targeted cisplatin prodrug delivery in vivo via metabolic labeling and bioorthogonal click reaction.

The discrepancy of surface receptors on cancerous and non-cancerous cells has been regarded as the mainstay of cancer-targeted therapy. However, due to the heterogeneity of tumor cells and the insufficient levels of receptors on the tumor cell surface, the success of cancer cell-targeted therapies is largely limited. Histone deacetylase/cathepsin l-responsive acetylated azidomannose (DCL-AAM) was previously developed to effectively and selectively label cancer cell surfaces with reactive azido groups via sugar metabolism. Herein, the labeling kinetics and generality of DCL-AAM were systematically investigated in varieties of tumor cells in vitro and in SKOV3 xenograft tumors in vivo. Based on this, dibenzocyclooctyne-cisplatin (DBCO-Pt) prodrug was developed, and DCL-AAM-mediated metabolic labeling of SKOV3 cells enhanced the tumor accumulation of DBCO-Pt ∼2 fold via bioorthogonal click chemistry, potentiating the anti-tumor efficacy of cisplatin yet alleviating the systemic toxicity. This work, therefore, provides the experimental and theoretical support for the future design of sugar metabolism-based targeted delivery systems and may provide a promising candidate for the treatment of cancers lacking appropriate biomarkers.