Nonsmall cell lung cancer (NSCLC) is the leading cause of
cancer-related death worldwide. Herein, we develop a
polypeptide-based block ionomer complex formed by anionic methoxy poly(
ethylene glycol)-b-poly(
L-glutamic acid) (
mPEG-b-PLG) and cationic anticancer
drug doxorubicin hydrochloride (DOX·HCl) for NSCLC treatment. This complex spontaneously self-assembled into spherical nanoparticles (NPs) in aqueous solutions via electrostatic interaction and hydrophobic stack, with a high loading efficiency (almost 100%) and negative surface charge. DOX·HCl release from the
drug-loaded micellar nanoparticles (
mPEG-b-PLG-DOX·HCl) was slow at physiological pH, but obviously increased at the acidic pH mimicking the endosomal/lysosomal environment. In vitro cytotoxicity and
hemolysis assays demonstrated that the block copolypeptide was cytocompatible and hemocompatible, and the presence of copolypeptide carrier could reduce the
hemolysis ratio of DOX·HCl significantly. Cellular uptake and cytotoxicity studies suggested that
mPEG-b-PLG-DOX·HCl was taken up by A549 cells via endocytosis, with a slightly slower cellular internalization and lower cytotoxicity compared with free DOX·HCl. The pharmacokinetics study in rats showed that DOX·HCl-loaded micellar NPs significantly prolonged the blood circulation time. Moreover,
mPEG-b-PLG-DOX·HCl exhibited enhanced therapeutic efficacy, increased apoptosis in
tumor tissues, and reduced systemic toxicity in nude mice bearing A549
lung cancer xenograft compared with free DOX·HCl, which were further confirmed by histological and immunohistochemical analyses. The results demonstrated that
mPEG-b-PLG was a promising vector to deliver DOX·HCl into
tumors and achieve improved pharmacokinetics, biodistribution and efficacy of DOX·HCl with reduced toxicity. These features strongly supported the interest of developing
mPEG-b-PLG-DOX·HCl as a valid therapeutic modality in the
therapy of human NSCLC and other solid
tumors.