A method for the precise cellular destruction of an oncogenic non-coding RNA with a RNA-binding small molecule conjugated with bleomycin A5 is described. The method affords reversal of phenotype. Bleomycin A5 was coupled to an RNA-binding molecule that selectively binds the microRNA-96 hairpin precursor (pri-miR-96). By coupling of bleomycin A5's free amine to the RNA-binding molecule, its affinity for binding to pri-miR-96 is >100-fold stronger than to DNA. The conjugate compound selectively cleaves pri-miR-96 in triple negative breast cancer (TNBC) cells. Selective cleavage of pri-miR-96 enhances expression of FOXO1 protein, a pro-apoptotic transcription factor that miR-96 silences, and triggers apoptosis in TNBC cells. No effects were observed in healthy breast epithelial cells. This method provides programmable control for targeting RNA through the selection of an RNA-binding molecule/bleomycin A5 conjugate and provides a facile method of mapping the cellular binding sites of an RNA-binding molecule.
