Photodynamic Oncotherapy Mediated by Gonadotropin-Releasing Hormone Receptors

Here, we report photodynamic oncotherapies mediated by gonadotropin-releasing hormone (GnRH) receptors. We synthesized conjugates 1 and 2 by coupling zinc phthalocyanine (ZnPc) to GnRH analogues. Compared to unmodified ZnPc, conjugates 1 and 2 exhibited higher and more specific phototoxicities to breast cancer cells. Furthermore, the two conjugates demonstrated excellent antitumor efficacies in a breast cancer-grafted animal model. Biodistribution study suggested the high biosafety of conjugate 2 because of the low retention in brain and skin.