A Therapeutic Pretargeting Strategy for Triple‐Negative Breast Cancer Based on a Bioorthogonal Reaction and a Self‐Assembled Peptide

Abstract Triple‐negative breast cancer (TNBC), a disease with a poor prognosis and high mortality, is difficult to targeted therapy, due to the metastatic nature of TNBC cells and their lack of estrogen, progesterone, and Her‐2/Neu receptor targets. Here, a novel pretargeting strategy involving self‐assembled peptides and a bioorthogonal reaction are described. This process generates nanofibers on TNBC cell surface that prevent them migration and invasion and deliver untargeted anticancer drugs (e.g., doxorubicin) that synergistically eliminates TNBC cells. The self‐assembled peptide contains four modules: i) an aromatic group‐rich tetraphenylethylene (TPE) unit for promoting self‐assembly and nanofiber formation, ii) a GFFY peptide motif that supports self‐assembly of nanofibers into peptide scaffolds, iii) a targeting RGD motif that binding with the abundant integrin molecules present on TNBC cell surface, and iv) an azide group acting as the bioorthogonal reaction site that reacts with drugs or probes containing the dibenzocyclooctyne (DBCO) group. Results of in vitro and in vivo experiments indicate that the self‐assembled peptide inhibits tumor invasion and metastasis, while also pretargeting and killing TNBC cells with superior effectiveness and lower toxicity to that of current chemotherapies. In conclusion, this novel bioorthogonal pretargeting strategy holds promise as an effective anticancer therapeutic approach.