Hillier SM, Maresca KP, Femia FJ, Marquis JC, Foss CA, Nguyen N, Zimmerman CN, Barrett JA, Eckelman WC, Pomper MG, Joyal JL, Babich JW. Preclinical evaluation of novel glutamate-urea-lysine analogues that target prostate-specific membrane antigen as molecular imaging pharmaceuticals for prostate cancer.
Cancer Res 2009;
69:6932-40. [PMID:
19706750 DOI:
10.1158/0008-5472.can-09-1682]
[Citation(s) in RCA: 241] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Prostate-specific membrane antigen (PSMA) is expressed in normal human prostate epithelium and is highly up-regulated in prostate cancer. We previously reported a series of novel small molecule inhibitors targeting PSMA. Two compounds, MIP-1072, (S)-2-(3-((S)-1-carboxy-5-(4-iodobenzylamino)pentyl)ureido)pentanedioic acid, and MIP-1095, (S)-2-(3-((S)-1carboxy-5-(3-(4-iodophenyl)ureido)pentyl)ureido)pentanedioic acid, were selected for further evaluation. MIP-1072 and MIP-1095 potently inhibited the glutamate carboxypeptidase activity of PSMA (K(i) = 4.6 +/- 1.6 nmol/L and 0.24 +/- 0.14 nmol/L, respectively) and, when radiolabeled with (123)I, exhibited high affinity for PSMA on human prostate cancer LNCaP cells (K(d) = 3.8 +/- 1.3 nmol/L and 0.81 +/- 0.39 nmol/L, respectively). The association of [(123)I]MIP-1072 and [(123)I]MIP-1095 with PSMA was specific; there was no binding to human prostate cancer PC3 cells, which lack PSMA, and binding was abolished by coincubation with a structurally unrelated NAALADase inhibitor, 2-(phosphonomethyl)pentanedioic acid (PMPA). [(123)I]MIP-1072 and [(123)I]MIP-1095 internalized into LNCaP cells at 37 degrees C. Tissue distribution studies in mice showed 17.3 +/- 6.3% (at 1 hour) and 34.3 +/- 12.7% (at 4 hours) injected dose per gram of LNCaP xenograft tissue, for [(123)I]MIP-1072 and [(123)I]MIP-1095, respectively. [(123)I]MIP-1095 exhibited greater tumor uptake but slower washout from blood and nontarget tissues compared with [(123)I]MIP-1072. Specific binding to PSMA in vivo was shown by competition with PMPA in LNCaP xenografts, and the absence of uptake in PC3 xenografts. The uptake of [(123)I]MIP-1072 and [(123)I]MIP-1095 in tumor-bearing mice was corroborated by single-photon emission computed tomography/computed tomography (SPECT/CT) imaging. PSMA-specific radiopharmaceuticals should provide a novel molecular targeting option for the detection and staging of prostate cancer.
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