title: Highly potent metallopeptide analogues of luteinizing hormone-releasing hormone.
abstract: Metal complexes related to the cytotoxic complexes cisplatin [cis-diamminedichloroplatinum(II)] and transbis(salicylaldoximato)copper(II) were incorporated into suitably modified luteinizing hormone-releasing hormone (LH-RH) analogues containing D-lysine at position 6. Some of the metallopeptides thus obtained proved to be highly active LH-RH agonists or antagonists. For instance, SB-40, a PtCl2-containing metallopeptide in which platinum is coordinated to an N epsilon-(DL-2,3-diaminopropionyl)-D-lysine residue [D-Lys(DL-A2pr] at position 6, showed 50 times higher LH-releasing potency than the native hormone. SB-95, [Ac-D-Nal(2)1,D-Phe(pCl)2, D-Pal(3)2, Arg5,D-Lys[DL-A2pr(Sal2Cu)]6,D-Ala10]LH-RH, where Nal(2) is 3-(2-naphthyl)alanine, Pal(3) is 3-(3-pyridyl)alanine, and copper(II) is coordinated to the salicylideneimino moieties resulting from condensation of salicylaldehyde with D-Lys(DL-A2pr)6, caused 100% inhibition of ovulation at a dose of 3 micrograms in rats. Most metallopeptide analogues of LH-RH showed high affinities for the membrane receptors of rat pituitary and human breast cancer cells. Some of these metallopeptides had cytotoxic activity against human breast cancer and prostate cancer cell lines in vitro (this will be the subject of a separate paper on cytotoxicity evaluation). Such cytostatic metallopeptides could be envisioned as targeted chemotherapeutic agents in cancers that contain receptors for LH-RH-like peptides.
authors.affiliation: Endocrine Polypeptide and Cancer Institute, Veterans Administration Medical Center, New Orleans, LA.
authors.forename: S
authors.initials: S
authors.lastname: Bajusz
authors.forename: T
authors.initials: T
authors.lastname: Janaky
authors.forename: V J
authors.initials: VJ
authors.lastname: Csernus
authors.forename: L
authors.initials: L
authors.lastname: Bokser
authors.forename: M
authors.initials: M
authors.lastname: Fekete
authors.forename: G
authors.initials: G
authors.lastname: Srkalovic
authors.forename: T W
authors.initials: TW
authors.lastname: Redding
authors.forename: A V
authors.initials: AV
authors.lastname: Schally
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001943:Breast Neoplasms / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D002945:Cisplatin / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000494:pharmacology; D003300:Copper / Q000494:pharmacology; D004151:Dipeptides / Q000138:chemical synthesis; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D007986:Luteinizing Hormone / Q000378:metabolism; D008969:Molecular Sequence Data; D009532:Nickel; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000494:pharmacology; D010060:Ovulation / Q000187:drug effects; D010902:Pituitary Gland / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D011966:Receptors, LHRH / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D004151:Dipeptides; D009942:Organometallic Compounds; D011966:Receptors, LHRH; C046547:bis(salicylaldoximato)copper(II); D007987:Gonadotropin-Releasing Hormone; D003300:Copper; D009532:Nickel; D007986:Luteinizing Hormone; D002945:Cisplatin