Inhibitory effect of somatostatin Peptide analogues on DNA polymerase activity and human cancer cell proliferation.

BACKGROUND AND OBJECTIVES

It was previously reported that ten small peptides derived from TT-232, somatostatin structural analogue (compounds 1-10), synthesised by a solution-phase method, exhibited potent antitumour activity on human epithelial tumour (A431) cells.

MATERIALS AND METHODS

The present study investigated the inhibitory activity of these peptide compounds against DNA polymerase (pol) and human cancer cell growth.

RESULTS

Among the compounds tested, compounds 1-5, which contain a t-butyloxycarbonyl (Boc) group, inhibited the activity of mammalian pols. Compounds 2 (Boc-Tyr-D-Trp-1-adamantylamide) and 3 (Boc-Tyr-D-Trp-2-adamantylamide) strongly suppressed the growth of a human colon carcinoma (HCT116) cell line and also arrested HCT116 cells in S phase, suggesting that these phenomena observed in cancer cells may be due to the selective inhibition of mammalian pols, especially DNA replicative pol α, by these compounds. Compound 2 induced apoptosis of the cells, although compound 3 did not.

CONCLUSION

Compounds 2 and 3 had an enhanced anticancer effect based on pol inhibition.