Single-cell and longitudinal transcriptomics-guided engineering of FZD1-targeting precision nanotherapy against osteosarcoma cancer stem cells.

Osteosarcoma is the most prevalent primary malignant bone tumor in children and adolescents. Osteosarcoma cancer stem cells (OCSCs) critically drive tumorigenesis and progression through their self-renewal capacity and therapy resistance. Understanding mechanisms maintaining OCSC stemness and identifying key therapeutic targets are thus critical for effective intervention. Here, we systematically analyzed OCSC transcriptomic features using single-cell and longitudinal RNA-sequencing, identifying transcription factor 7 like 1 (TCF7L1)-associated transcriptional activity in relation to OCSC stemness and frizzled class receptor 1 (FZD1)-associated Wnt/β-catenin signaling as a putative upstream pathway. FZD1 expression significantly correlated with clinical malignancy progression in osteosarcoma. Leveraging these transcriptional signatures, we screened and validated homoharringtonine as a potent therapeutic agent against osteosarcoma and OCSCs. To enhance efficacy while reducing systemic toxicity, an FZD1-targeted, pH/glutathione dual-responsive nanoplatform was engineered to achieve precise drug delivery to OCSC-derived tumors via high-affinity binding of UM206 peptide to FZD1, concurrently enabling tumor microenvironment-triggered homoharringtonine release in acidic, glutathione-rich niches. This integrated approach characterizes OCSC-associated transcriptional regulation and supports further development of OCSC-targeted precision nanotherapies for osteosarcoma.