title: Enhancement of tumor uptake and therapeutic efficacy of EGFR-targeted antibody cetuximab and antibody-drug conjugates by cholesterol sequestration.
abstract: Cetuximab, a monoclonal antibody (mAb) targeting the epidermal growth factor receptor (EGFR), has been intensively investigated as a promising cancer treatment strategy. The specific mechanism of cetuximab endocytosis and its influence on cetuximab uptake, biodistribution and efficacy still remain elusive. Recently, statins have been reported to synergize with EGFR-targeting agents. Our prior work established that nystatin, a cholesterol-sequestering antifungal drug, facilitates endocytosis via the clathrin-dependent pathway. This study aimed to investigate whether nystatin regulates the uptake and efficacy of cetuximab and cetuximab-based antibody-drug conjugates (cetuximab-ADCs). In vitro and in vivo efficacies of nystatin on the uptake and activity of cetuximab/cetuximab-ADCs were studied in multiple human carcinoma cell lines and xenograft models, respectively. We identified that cholesterol sequestration by nystatin enhanced cetuximab internalization in EGFR-positive carcinoma cells by regulating EGFR trafficking/turnover and facilitating a switch from lipid rafts to clathrin-mediated endocytosis. Combination treatment with cetuximab and nystatin selectively increased cetuximab uptake by tumor tissues, translating into potentiated antitumor efficacy of cetuximab in vivo (A431 and A549 tumors). Nystatin-enhanced internalization of cetuximab further improved the uptake and potency of cetuximab-doxorubicin and cetuximab-methotrexate conjugates in EGFR-positive cetuximab-resistant tumors. Combination therapy with nystatin plus either cetuximab or cetuximab-ADC further prolonged animal survival and significantly suppressed tumor growth, as compared with single-agent cetuximab or cetuximab-ADC. In summary, our results identify a novel mechanism whereby cholesterol sequestration enhances the uptake of EGFR-targeting mAb and ADCs, therefore providing preclinical proof-of-concept that combination with nystatin can potentiate the delivery and efficacy of these EGFR-targeted agents.
authors.affiliation: The National Engineering Laboratory for Anti-Tumor Protein Therapeutics, Tsinghua University, Beijing, 100084, China; Beijing Key Laboratory for Protein Therapeutics, Tsinghua University, Beijing, 100084, China; Cancer Biology Laboratory, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Chen
authors.forename: Guanghua
authors.initials: G
authors.lastname: Liu
authors.forename: Lifang
authors.initials: L
authors.lastname: Guo
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Yan
authors.initials: Y
authors.lastname: Fu
authors.forename: Yongzhang
authors.initials: Y
authors.lastname: Luo
mesh_terms: D000818:Animals; D061067:Antibodies, Monoclonal, Humanized / Q000008:administration & dosage; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000493:pharmacokinetics / Q000627:therapeutic use*; D001692:Biological Transport; D045744:Cell Line, Tumor; D000068818:Cetuximab; D002784:Cholesterol / Q000378:metabolism*; D004317:Doxorubicin / Q000008:administration & dosage; D019008:Drug Resistance, Neoplasm / Q000187:drug effects; D004357:Drug Synergism; D004705:Endocytosis; D066246:ErbB Receptors / Q000037:antagonists & inhibitors; D006801:Humans; D021962:Membrane Microdomains / Q000378:metabolism; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009761:Nystatin / Q000008:administration & dosage; D014018:Tissue Distribution; D047368:Tumor Burden / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D009761:Nystatin; D004317:Doxorubicin; D002784:Cholesterol; C512478:EGFR protein, human; D066246:ErbB Receptors; D000068818:Cetuximab
keywords: EGFR; internalization; lipid rafts; nystatin; therapeutic antibody