[Cancer Research 66, 5371-5378, May 15, 2006]
© 2006 American Association for Cancer Research
Experimental Therapeutics, Molecular Targets, and Chemical Biology
Inhibition of Tumor Growth and Elimination of Multiple Metastases in Human Prostate and Breast Xenografts by Systemic Inoculation of a Host Defense–Like Lytic Peptide
Niv Papo1, Dalia Seger2, Arik Makovitzki1, Vyacheslav Kalchenko3, Zelig Eshhar4, Hadassa Degani2 and Yechiel Shai1
Departments of 1 Biological Chemistry, 2 Biological Regulation, 3 Veterinary Resources, and 4 Immunology, The Weizmann Institute of Science, Rehovot, Israel
Requests for reprints: Yechiel Shai, Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, 76100 Israel. Phone: 972-8-934-2711; Fax: 972-8-934-4112; E-mail:
Yechiel.Shai@weizmann.ac.il.
We report on a short host defense–like peptide that targets and arrests the growth of aggressive and hormone-resistant primary human prostate and breast tumors and prevents their experimental and spontaneous metastases, respectively, when systemically inoculated to immuodeficient mice. These effects are correlated with increased necrosis of the tumor cells and a significant decrease in the overall tumor microvessel density, as well as newly formed capillary tubes and prostate-specific antigen secretion (in prostate tumors). Growth inhibition of orthotopic tumors derived from stably transfected highly fluorescent human breast cancer cells and prevention of their naturally occurring metastases were visualized in real time by using noninvasive whole-body optical imaging. The exclusive selectivity of the peptide towards cancer derives from its specific binding to surface phosphatidylserine and the killing of the cancer cells via cytoplasmic membrane depolarization. These data indicate that membrane disruption can provide a therapeutic means of inhibiting tumor growth and preventing metastases of various cancers. (Cancer Res 2006; 66(10): 5371-8)