Compound 1632 (C1632) is a RNA-binding protein Lin28 inhibitor th at prevents Lin28-mediated inhibition of let-7 microRNA (miRNA) maturation by blocking Lin28 interaction with let-7 miRNA precursor (IC50 = 8 μM by ELISA using truncated pre-let-7a-2). C1632 specifically upregulates Huh7 cellular let-7a/g/f miRNA, but not RNU44 snoRNA (60 μM for 48h), inhibits the stemness and induces differentiation of mouse embryonic stem cells (mESCs, 20 μM for 48h), as well as inhibits the proliferation and stem-like properties of human cancer stem cells (CSCs) in 22Rv1 and Huh7 cultures (IC50 20-42 μM).