{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,28]],"date-time":"2026-10-28T23:37:26Z","timestamp":1793230646749,"version":"4.5.0"},"reference-count":32,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2025,9,12]],"date-time":"2025-09-12T00:00:00Z","timestamp":1757635200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100018234","name":"Inselspital, Universit\u00e4tsspital Bern","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100018234","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Pharmacol."],"abstract":"<jats:sec><jats:title>Introduction<\/jats:title><jats:p>Acute Myeloid Leukemia (AML) is a group of very aggressive hematological malignancies, with dismal long-term survival rates and little therapeutic recourse presently. The transmembrane ligand B7-H3 is a known therapeutic target, biomarker of response and correlated with an unfavorable prognosis in several malignancies, including AML, due to acquired resistance to immune checkpoint-targeting therapies. Therefore, developing therapeutic strategies with improved efficacy to overcome this obstacle constitutes an unmet need. Our study entails the design, production and <jats:italic>in vitro<\/jats:italic> testing of a novel recombinant Affibody with high affinity for B7-H3 coupled with the cytotoxic peptide Magainin-2, known for its membranolytic properties and potent antimicrobial and antitumor activity.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>We expressed the conjugate in <jats:italic>Escherichia coli<\/jats:italic>, affinity purified it and confirmed its sequence by nanoLC-MS\/MS. B7-H3-positive AML representative THP-1 cells and B7-H3-negative B-lymphoblastic RAJI cells were used for the experiments. The IC<jats:sub>50<\/jats:sub> of the cytotoxic conjugate was determined through MTS assay and its necrotic, apoptotic and antiproliferative activities were evaluated by flow cytometry and Western blot.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Overall, the results show that our cytotoxic anti-B7-H3 affibody possesses strong antiproliferative and cell death-inducing activity that is highly specific to B7-H3-expressing AML cells (IC<jats:sub>50<\/jats:sub> against THP-1 cells was 26.35\u00a0\u00b5M). Moreover, this observed activity of our conjugate is significantly more potent than the previously described activity of Magainin-2 alone.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>In conclusion, we designed, produced and evaluated a novel anti-B7-H3 cytotoxic affibody-drug conjugate (AfDC) that, from these preliminary <jats:italic>in vitro<\/jats:italic> data, shows high potential for translation to the therapy of AML, warranting further preclinical and translational exploration, including pharmacokinetic and <jats:italic>in vivo<\/jats:italic> efficacy studies.<\/jats:p><\/jats:sec>","DOI":"10.3389\/fphar.2025.1684226","type":"journal-article","created":{"date-parts":[[2025,9,12]],"date-time":"2025-09-12T07:49:35Z","timestamp":1757663375000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":1,"title":["A novel cytotoxic anti-B7-H3 affibody with therapeutic potential in acute myeloid leukemia"],"prefix":"10.3389","volume":"16","author":[{"given":"Andrei-Mihai","family":"Vasilescu","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Adina-Gabriela","family":"Vasilescu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Livia Elena","family":"Sima","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cristian V. 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