Cinobufagin targets POU6F1 to downregulate LINC01410-mediated proliferation and metastasis in osteosarcoma

Background Venenum bufonis (VB) is a traditional Chinese medicine (TCM) extracted from toad venom that has been used to treat various tumours. Cinobufagin (CBG), a major bioactive compound derived from the VB, has demonstrated clinical efficacy against metastatic bone tumours, but its LncRNA-modulating mechanisms in osteosarcoma (OS) remain unknown.This study investigates a novel mechanism by which CBG exerts its anti-tumor effects through targeting long non-coding RNAs (LncRNAs). Methods OS cell lines were treated with CBG. A series of cell biological experiments were performed to detect the effects of CBG on the proliferation, migration and invasion of osteosarcoma cells. RNA sequencing identified CBG-regulated lncRNAs. Proteome microarray analysis was used to screen for transcription factors that bind to CBG. Molecular docking and microscale thermophoresis experiments confirmed the binding of CBG to POU6F1. Chromatin immunoprecipitation and dual-luciferase reporter assays validated POU6F1 binding and the transcriptional regulation of LINC01410. In vivo , the efficacy of CBG in the treatment of OS proliferation and pulmonary metastasis was evaluated in subcutaneous xenograft and lung metastasis models. Results The experimental results show that CBG inhibits the malignant progression of OS, including proliferation and lung metastasis. RNA-seq revealed that LINC01410 is a key oncogenic lncRNA downregulated by CBG. Mechanistically, CBG directly binds to the transcription factor POU6F1 and inhibits its occupancy of the LINC01410 promoter, thereby inhibiting PI3K/AKT/mTOR signalling. Our study provides the first evidence for the mechanism by which CBGs target lncRNAs. Conclusions CBG exerts anti-OS effects by disrupting POU6F1-mediated transcription of LINC01410, thereby inactivating PI3K/AKT/mTOR signalling. This study supports the development of CBG as a therapeutic agent derived from TCM.