Multiple responsive Nano-Prodrug Combining Chemo-Differentiation-Cancer Stem Cells Inhibition toward Triple-Negative Breast Cancer

Abstract

To overcome therapy resistance driven by breast cancer stem cells (BCSCs) and systemic toxicity of conventional chemotherapy, we engineered a multistimuli-responsive nanoprodrug (DT/PAC@AI NPs) implementing a "chemodifferentiation-cancer stem cells inhibition" strategy. This system co-delivers irinotecan (IRI), all-trans retinoic acid (ATRA), and CPUL119 via: (1) a hypoxia-responsive prodrug (PAC: PEG₂ₖ-Azo-CPUL119), and (2) a pH/esterase-responsive conjugate (AI: ATRA-IRI). The targeted NPs (90-130 nm), modified with DSPE-PEG₂ₖ-Try for LAT1mediated uptake, demonstrated tumor microenvironment-triggered release: rapid PAC release under hypoxia and enhanced AI release at pH 5.0/esterase. In vitro, DT/PAC@AI NPs showed 20% higher cellular uptake and potent cytotoxicity against MDA-MB-231 cells (IC₅₀ = 4.77 ± 0.32 µM vs. free drugs: IRI 23.17, CPUL119 9.27, ATRA >50 µM), inducing 3.7-fold more apoptosis (32.6% vs. 8.7%). Critically, they reduced CD44⁺/CD24⁻ BCSCs by 13.7% and inhibited tumor sphere formation by 87.6%. In vivo, they achieved optimal tumor suppression and BCSC elimination in xenografts with negligible systemic toxicity. This nanoprodrug platform offers straightforward synthesis, high drug loading, and potent dual-action efficacy against bulk tumor cells and BCSCs, presenting a promising advanced breast cancer therapy.