The invention relates to anti-integrin antibodies which are covalently linked to nanoparticles, wherein these nanoparticles were prior loaded with chemotherapeutic/cytotoxic agents. The antibody-chemotherapeutic agent-nanoparticle conjugates according to the invention, especially wherein the antibody is MAb DI17E6 and the cytotoxic agent is doxorubicin show a significant increase of tumor cell toxicity.