LIN28-IN-1 (compound 5) is a selective inhibitor targeting the RNA-binding protein LIN28, specifically binding to its cold shock domain (CSD). This compound robustly interrupts the LIN28-let-7 miRNA interaction with an IC 50 of 5.4 μM, thereby mitigating LIN28's adverse effects on epigenetic gene control. Furthermore, LIN28-IN-1 exhibits significant anti-proliferative activity against LIN28-expressing JAR cancer cells, evidenced by an IC 50 value of 6.4 μM [1].