Inhibition of cancer cell growth by cyclin dependent kinase 4 inhibitors synthesized based on the structure of fascaplysin

CA199, a tryptamine analogue of fascaplysin, is a specific inhibitor of Cdk4-D1 in enzyme assays, blocks cancer cells at G0/G1 and prevents pRb hyperphosphorylation, but does not bind or intercalate DNA like fascaplysin.