RT Journal Article SR Electronic T1 Selected Cyclic Dipeptides Inhibit Cancer Cell Growth and Induce Apoptosis in HT-29 Colon Cancer Cells JF Anticancer Research JO Anticancer Res FD International Institute of Anticancer Research SP 1713 OP 1720 VO 24 IS 3A A1 SETH CLINT BRAUNS A1 PIETER MILNE A1 RYNO NAUDÉ A1 MARYNA VAN DE VENTER YR 2004 UL http://ar.iiarjournals.org/content/24/3A/1713.abstract AB Background: An increasing number of cyclic dipeptides (CDPs), particularly those containing proline, have been shown to exhibit important biological activity. Materials and Methods: We investigated the potential of seven proline-based CDPs to inhibit cancer cell growth in HT-29, HeLa and MCF-7 cell lines. We also tested whether any of the CDPs were able to induce apoptosis in HT-29 cells. Results: The SRB assay showed that only cyclo(Phe-Pro) (10 mM) exhibited more than 50% growth inhibition (p<0.01). The MTT assay was used to demonstrate a dose-dependent (0.008-10 mM) growth inhibition by cyclo(Phe-Pro). Hoechst 33342 staining showed that 5 mM cyclo(Phe-Pro) induced chromatin condensation in 18.3±2.8% (p<0.01) of HT-29 cells after 72 hours. Furthermore, annexin V binding revealed phosphatidylserine externalisation in cyclo(Phe-Pro)-treated HT-29 cells. Conclusion: Our findings demonstrate that cyclo(Phe-Pro) inhibits the growth of HT-29, MCF-7 and HeLa cells and induces apoptosis in HT-29 colon cancer cells, suggesting a potential antitumour activity. Copyright© 2004 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved