Construction of a biotin-targeting drug delivery system and its near-infrared theranostic fluorescent probe for real-time image-guided therapy of lung cancer

The therapy of non-small lung cancer (NSCLC) is limited by wide metastasis and chemotherapy resistance, herein, we present a new cancer-targeting prodrug PBG with the integration of real-time fluorescence visualization. The potent anticancer drug Gefitinib conjugates a biotin recognition ligand yielding the prodrug PBG via a GSH-activatable disulfide bond linker. Once coupling a near-infrared azo-BODIPY fluorophore into the molecular structure of PBG, we obtain its fluorescent theranostic TBG. The prodrug PBG can sustain Gefitinib release by the high level of GSH in the pathophysiological milieu. We evaluate the drug delivery of the prodrug PBG using fluorescent TBG in PC9 cancer bearing nude mice models, which indicate that TBG can be utilized to monitor the in vivo drug release process. Prodrug PBG can be targeted to accumulate in the cancer lesion with a better and efficaciously therapeutic result compared with the single Gefitinib treatment in cells and in vivo. The fluorescence images also reveal that the targeting accumulation and longitudinal retention of anticancer drug in cancer lesions will contribute to the superior therapeutic effects. The above applications of our new prodrug PBG and its fluorescent theranostic TBG have the potential contribution to the research in biology and the clinical medicine.