Aclacinomycin A (Aclarubicin) hydrochloride is a fluorescent molecule and the first described non-peptidic inhibitor with discrete specificity for the CTRL (chymotrypsin-like) activity of the 20S proteasome. Additionally, it is a dual inhibitor of topoisomerase I and II.

Aclacinomycin A can efficiently penetrate living cells, enabling in situ fluorescence visualization. A mere 15-minute exposure to a 10 μM concentration of Aclacinomycin A suffices for distinct fluorescence detection across various cultured cell lines. This treatment also leads to approximately 20% cell mortality (or near mortality) [1]. Furthermore, Aclacinomycin A has been shown to effectively stimulate the inclusion of exon 7 into SMN2 transcripts, both from the endogenous gene in type I SMA fibroblasts and from an SMN2 minigene in NSC34 motor neuron cell lines [2].