Liver metastasis is one of the major causes of colorectal cancer (CRC)-related morbidity and mortality. Delivering small interfering RNAs (siRNAs) or noncoding RNAs has been reported as a promising method to target liver metastasis and chemoresistance in CRC. Here, we report a noncoding RNA delivery system using exosomes derived from primary patient cells. Coiled-coil domain-containing protein 80 (CCDC80) was strongly associated with CRC liver metastasis and chemoresistance, a finding validated by bioinformatic analysis and clinical specimens. Silencing CCDC80 significantly increased sensitivity to chemotherapy agents in OXA-resistant cell lines and a mouse model. The primary cell-derived exosome delivery system was designed to simultaneously deliver siRNAs targeting CCDC80 and increase chemotherapy sensitivity in the distant CRC liver metastasis mouse models and patient-derived xenograft mouse models. We further validated the antitumor effect in an ex vivo model of chemoresistant CRC organoids and a patient-derived organoid xenograft model. Tumor-bearing mice treated with the siRNA-delivering exosomes and hepatectomy showed ideal overall survival. Our results provide a therapeutic target and represent a possible therapeutic alternative for patients with CRC and distant metastasis and in cases of chemoresistance.
Keywords: chemoresistance; colorectal cancer; engineered exosomes; liver metastasis; organoid; siRNA delivery.