Combination of lactoferrin-based microparticles and carboanhydrase II inhibitor demonstrates enhanced inhibition effect on Ewing sarcoma cells.

Ewing sarcoma (ES) is a highly aggressive pediatric malignancy with limited treatment options and frequent development of drug resistance. In this case, novel drug delivery systems may overcome tumor resistance and improve therapeutic efficacy. We developed lactoferrin-chondroitin sulfate microparticles (Lf-ChS MPs) that can be loaded with the carbonic anhydrase II inhibitor OX72. Their physicochemical properties were characterized by AFM, FTIR, zeta potential, DSC/TGA, and drug release assays. In vitro cytotoxicity was evaluated in ES cell lines (A673, ES36, T69, and doxorubicin-resistant A673 cells), with 977hTERT fibroblasts as controls. Drug encapsulation significantly enhanced the antiproliferative activity of OX72 in ES36 and A673 cells, as well as in doxorubicin-resistant cells. Mechanistically, Lf-ChS-OX72 reduced FTH1 expression, indicating ferroptosis induction, with no influence on apoptosis. Lf-ChS microparticles provide a promising platform for OX72 delivery inducing ferroptosis-mediated cytotoxicity in doxorubicin-resistant sarcoma cells.