Anti-Cancer Activity of the Macrocyclic Tetrapeptides

Because opioid receptors have been reported on cancer cells we examined whether peptides synthesized in our lab could decrease the proliferation of prostate cancer cells. Both the macrocyclic tetrapeptides CJ-15,208 and [D-Trp]CJ-15,208 exhibited antiproliferative activity in these cells which appears to involve degradation of the oncoprotein c-Myc. Current studies are further exploring the mechanism of action of the peptides, particularly their effects on proteins in the c-Myc degradation pathway, and examining their SAR for anticancer activity with the goal of improving potency. We are also examining the peptides’ antiproliferative effects in vivo and in other cancers.


  1. Mukhopadhyay, L.E. Hanold, H. Thayele Purayil, S. Gisemba, S. Sanadheera, J.V. Aldrich. Macrocyclic peptides decrease c-Myc protein levels and reduce prostate cancer cell growth. Cancer Biol Ther. 2017, 18, 571-583.