[Ac-D2Nal1, D-4Cpa2, D-3Pal3,6, Leu8, D-Ala10]GnRH-II

**[Ac-D2Nal1, D-4Cpa2, D-3Pal3,6, Leu8, D-Ala10]GnRH-II** is a synthetic peptide analog that acts as a selective antagonist of the gonadotropin-releasing hormone type II receptor. It is engineered by introducing non-natural D-amino acids into the GnRH-II sequence to enhance metabolic stability and antagonistic activity. This analog directly induces apoptosis and inhibits cell proliferation in various human cancer cell models, including breast cancer, by blocking GnRH-II signaling. Its primary investigated use is as an experimental antitumor agent, particularly in hormone-dependent and triple-negative breast cancer, where it promotes tumor cell death and inhibits tumor growth in vitro and in vivo[1][3][4][5][6]. The compound was synthesized by Peptide Specialty Laboratories and developed in academic research settings for preclinical studies.