title: PSMA-targeted stably linked "dendrimer-glutamate urea-methotrexate" as a prostate cancer therapeutic.
abstract: One of the important criteria for achieving efficient nanoparticle-based targeted drug delivery is that the drug is not prematurely released at off-target sites. Here we report the preclinical evaluation of a serum-stable dendrimer-based drug conjugate capable of actively targeting into prostate cancer (PC) cells, delivered through the prostate-specific membrane antigen (PSMA). Multiple molecules of PSMA-binding small molecule glutamate urea (GLA; targeting agent) and the drug methotrexate (MTX) were conjugated to generation 5 PAMAM dendrimer (G5) through Cu-free "click" chemistry. The GLA was conjugated through a stable amide bond, and the MTX was conjugated either through ester (Es)- or amide (Am)-coupling, to generate G5-GLA(m)-(Es)MTX(n) and G5-GLA(m)-(Am)MTX(n), respectively. In serum-containing medium, free MTX was slowly released from "G5-GLA(m)-(Es)MTX(n)", with ~8% MTX released from the dendrimer in 72 h, whereas the MTX on G5-GLA(m)-(Am)MTX(n) was completely stable. The G5-GLA(m)-(Am)MTX(n) bound and internalized into PSMA-expressing LNCaP cells, but not into PSMA-negative PC3 cells. The conjugate-inhibited recombinant dihydrofolate reductase and induced potent cytotoxicity in the LNCaP cells, but not in the PC3 cells. Similar to the action of free GLA, stable amide-linked dendrimer-GLA was capable of inhibiting the enzyme N-acetylated α-linked acidic dipeptidase (NAALADase) activity of PSMA. The G5-GLA(m)-MTX(n) may serve as a serum-stable nanoparticle conjugate to specifically and effectively target and treat PSMA-overexpressing prostate tumors.
authors.affiliation: Michigan Nanotechnology Institute for Medicine and Biological Sciences and Department of Internal Medicine, University of Michigan , Ann Arbor, Michigan 48109, United States.
authors.forename: Baohua
authors.initials: B
authors.lastname: Huang
authors.forename: James
authors.initials: J
authors.lastname: Otis
authors.forename: Melvin
authors.initials: M
authors.lastname: Joice
authors.forename: Alina
authors.initials: A
authors.lastname: Kotlyar
authors.forename: Thommey P
authors.initials: TP
authors.lastname: Thomas
mesh_terms: D000954:Antigens, Surface / Q000737:chemistry / Q000378:metabolism*; D057930:Click Chemistry; D050091:Dendrimers / Q000008:administration & dosage / Q000737:chemistry; D016503:Drug Delivery Systems; D043425:Glutamate Carboxypeptidase II / Q000737:chemistry / Q000378:metabolism*; D018698:Glutamic Acid / Q000737:chemistry; D006801:Humans; D008297:Male; D008727:Methotrexate / Q000008:administration & dosage / Q000737:chemistry; D053758:Nanoparticles / Q000008:administration & dosage* / Q000737:chemistry; D011471:Prostatic Neoplasms / Q000188:drug therapy*; D014508:Urea / Q000737:chemistry
chemical_list: D000954:Antigens, Surface; D050091:Dendrimers; C104700:PAMAM Starburst; D018698:Glutamic Acid; D014508:Urea; C473848:FOLH1 protein, human; D043425:Glutamate Carboxypeptidase II; D008727:Methotrexate