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Updated: Jun 13, 2026

A Flow Cytometry-Based Cell Surface Protein Binding Assay for Assessing Selectivity and Specificity of an Anticancer Aptamer
Published on: September 13, 2022
Aaptamine, an alkaloid from the sponge Aaptos suberitoides, functions as a proteasome inhibitor
Sachiko Tsukamoto1, Rumi Yamanokuchi, Makiko Yoshitomi
1Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Kumamoto 862-0973, Japan. sachiko@kumamoto-u.ac.jp
Abstract:
Aaptamine (1), isoaaptamine (2), and demethylaaptamine (3) were isolated from the marine sponge Aaptossuberitoides collected in Indonesia as inhibitors of the proteasome. They inhibited the chymotrypsin-like and caspase-like activities of the proteasome with IC(50) values of 1.6-4.6 microg/mL, while they showed less inhibition of the trypsin-like activity of the proteasome. The three compounds showed cytotoxic activities against HeLa cells, but their cytotoxicity did not correlate with their potency as proteasome inhibitors, strongly suggesting that their proteasomal inhibitory activity is dispensable to their cytotoxicity.
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