Laser-responsive erastin-loaded chondroitin sulfate nanomedicine targeting CD44 and system x in liver cancer: A non-ferroptotic approach.

Erastin, a ferroptosis-inducing system x inhibitor, faces clinical challenges due to suboptimal physicochemical and pharmacokinetic properties, as well as relatively low potency and off-target toxicity. Addressing these, we developed ECINs, a novel laser-responsive erastin-loaded nanomedicine utilizing indocyanine green (ICG)-grafted chondroitin sulfate A (CSA) derivatives. Our aim was to improve erastin's tumor targeting via CSA-CD44 interactions and enhance its antitumor efficacy through ICG's photothermal and photodynamic effects in the laser-on state while minimizing off-target effects in the laser-off state. ECINs, with their nanoscale size of 186.7 ± 1.1 nm and high erastin encapsulation efficiency of 93.0 ± 0.8%, showed excellent colloidal stability and sustained drug release up to 120 h. In vitro, ECINs demonstrated a mechanism of cancer cell inhibition via G1-phase cell cycle arrest, indicating a non-ferroptotic action. In vivo biodistribution studies in SK-HEP-1 xenograft mice revealed that ECINs significantly enhanced tumor distribution of erastin (1.9-fold greater than free erastin) while substantially reducing off-target accumulation in the lungs and spleen by 203-fold and 19.1-fold, respectively. Combined with laser irradiation, ECINs significantly decreased tumor size (2.6-fold, compared to free erastin; 2.4-fold, compared to ECINs without laser irradiation) with minimal systemic toxicity. This study highlights ECINs as a dual-modality approach for liver cancer treatment, demonstrating significant efficacy against tumors overexpressing CD44 and system x.