Assay of Novel Belactosin A/Carfilzomib Hybrids as Proteasome Inhibitors

Abstract

Proteasome inhibitors, such as bortezomib and carfilzomib that are used clinically, have proven to be effective against some types of cancer, including multiple myeloma and mantle cell lymphoma. Belactosin A, a naturally occurring inhibitor that is not used clinically has key properties, including a β−lactone that acts as a serine trap. In this project, novel compounds synthesized in Dr. Norma Dunlap’s lab based on belactosin A and carfilzomib were tested in an in vitro proteasome inhibition fluorescent assay using human 20S proteasome and the fluorogenic substrates Suc-LLVY-AMC and N-OMe-FLF-AMC. Bortezomib and MG-132, both known inhibitors, were also used as controls. In a phenotypic assay performed by Katie Sampuda, a former graduate student at MTSU, it was found that two of the novel compounds, NDMY1 and NDMY2, showed inhibition in an in vivo assay in C. elegans using confocal microscopy. After testing the novel compounds for this project in an in vitro assay, it was concluded that they showed no inhibition of the proteasome compared to the known inhibitors. There are plans to send these compounds to be tested in cancer cell lines to discover more details regarding their effectiveness as proteasome inhibitors.