A novel bicyclic peptide-drug conjugate of 3-fluoro-10-hydroxy-evodiamine for targeted colorectal cancer therapy.

This study aimed to develop a novel peptide-drug conjugate (PDC) by conjugating 3-fluoro-10-hydroxy-evodiamine (FOE) with a bicyclic peptide (BiP) targeting the EphA2 receptor. The goal was to enhance the solubility, tumor selectivity, and therapeutic efficacy of FOE against colorectal cancer (CRC). FOE and BiP were chemically synthesized and coupled through a valine-citrulline cleavable linker to generate BiP-FOE. The compound was structurally characterized, and its solubility, plasma stability, and in vitro cytotoxicity were evaluated in CRC cells. Its effects on cell migration, invasion, apoptosis, and the cell cycle were also assessed. The in vivo targeting ability, antitumor efficacy, and safety were evaluated in an HCT116 xenograft mouse model. BiP-FOE exhibited a greater than 200-fold improvement in aqueous solubility and good metabolic stability. In vitro, BiP-FOE showed selective and potent cytotoxicity toward EphA2-positive HCT116 cells, significantly inhibiting migration and invasion while inducing S-phase arrest and apoptosis. In vivo, BiP-FOE achieved significant accumulation at the tumor site and effectively suppressed tumor growth, with efficacy comparable to or exceeding that of 5-FU. It demonstrated a favorable safety profile, showing minimal body weight loss, negligible hemolysis, and no detectable organ toxicity. BiP-FOE successfully combines the cytotoxic potential of FOE with the tumor-targeting capacity of a bicyclic peptide, resulting in improved solubility, selectivity, efficacy, and safety. These findings highlight BiP-FOE as a promising candidate for targeted CRC therapy and warrant further preclinical development.