Anti-prostate cancer and anti-breast cancer activities of two peptides derived from alpha-fetoprotein.

A chemically synthesized 34-amino-acid peptide and a select analog have been studied to determine their activities against the growth of prostate and breast cancer tumors. It was of interest to determine if the peptide has anti-prostate cancer activity. Previously, the peptide was shown to inhibit the growth of breast cancer tumor cells. The peptide inhibited the growth of both breast and prostate tumors. A novel experimental design for the peptide was in a study in which a time-release pellet was used to give daily peptide doses to mice that were subjected to a breast cancer tumor. The peptide was effective in inhibiting the growth of tumors in the mice. The 2 C-->2 A analog peptide, in which the two cysteines were replaced by alanines, was also active in inhibition of the growth of prostate and breast cancer cell lines and in an in vivo assay against breast cancer. A scrambled amino acid sequence of the peptide was used as a control in these tumor studies, and it had virtually no anti-cancer activity.