CD44-targeted hyaluronic acid-podophyllotoxin micelles with dual-stimuli responsiveness for lung cancer therapy

Clinical application of podophyllotoxin (PPT) is significantly hampered by poor aqueous solubility and considerable systemic toxicity. Herein, we engineered dual-targeting and dual-cleavable prodrug micelles (HPMs) by conjugating PPT to hyaluronic acid (HA) backbone via a flexible, dual-responsive spacer, adipic dihydrazide-3,3'-dithiodipropionic acid (ADH-DTDPA). In vitro, HPMs demonstrated efficient CD44-mediated internalization in NCI-H1299 cells and rapidly disassembled under tumor microenvironment (TME) conditions (pH 5.0/GSH). Crucially, microscale thermophoresis (MST) provided quantitative evidence of the targeting mechanism, revealing a high binding affinity (K_D = 15.3 μM) for the CD44 receptor. In vivo, this design achieved effective accumulation of the micelles at tumor sites. Notably, HPMs (10 mg/kg) achieved superior tumor inhibition compared to free PPT (15 mg/kg) without inducing hepatotoxicity or nephrotoxicity. These findings provide a safe delivery strategy to overcome the clinical limitations of PPT and offer quantitative molecular insights into the rational design of targeted nanomedicines for lung cancer therapy.