OtherBasic Science Investigations

CCK-2/Gastrin Receptor–Targeted Tumor Imaging with 99mTc-Labeled Minigastrin Analogs

Berthold A. Nock, Theodosia Maina, Martin Béhé, Anastasia Nikolopoulou, Martin Gotthardt, Jörg S. Schmitt, Thomas M. Behr and Helmut R. Mäcke
Journal of Nuclear Medicine October 2005, 46 (10) 1727-1736;

Article Figures & Data

Figures

  • FIGURE 1.
    FIGURE 1.

    [99mTc]Demogastrin 1–3.

  • FIGURE 2.
    FIGURE 2.

    Saturation binding curve of [99mTc/99gTc]Demogastrin 2 in AR4-2J cell membranes with Scatchard plot in inset. Kd = 1.024 ± 0.07 nmol/L; Bmax = 516 ± 13 fmol/mg protein (Bmax is maximum number of binding sites).

  • FIGURE 3.
    FIGURE 3.

    Time-dependent internalization of [99mTc]Demogastrin 1–3 in CCK-2/gastrin–expressing AR4-2J cells at 37°C in absence (filled symbols: specific) or presence (open symbols: nonspecific) of competing (10−6 mol/L) [(D)Glu1]minigastrin: ▪, □, [99mTc]Demogastrin 1; •, ○, [99mTc]Demogastrin 2; and ▾, ▿, [99mTc]Demogastrin 3.

  • FIGURE 4.
    FIGURE 4.

    Degradation rates of [99mTc]Demogastrin 1–3 in murine plasma (A) and in mouse kidney homogenates (B): ▪, [99mTc]Demogastrin 1; •, [99mTc]Demogastrin 2; and ▾, [99mTc]Demogastrin 3.

  • FIGURE 5.
    FIGURE 5.

    γ-Trace from HPLC analysis of [99mTc]Demogastrin 2 after 2-h incubation at 37°C in kidney homogenates (A) in urine collected 30 min after intravenous injection of radiopeptide in mice (B) and reference [99mTc]Demogastrin 2 after labeling (C).

  • FIGURE 6.
    FIGURE 6.

    Selective data of [99mTc]Demogastrin 1–3 biodistribution in healthy mice at 30 min, 1, 2, and 4 h after injection in stomach (A), kidneys (B), and liver (C). Results are the average %ID/g values from groups of 4 animals at each time point. bl = blocked. Student t test was used for statistical analysis and a P value of <0.001 (***P) was considered extremely significant.

  • FIGURE 7.
    FIGURE 7.

    Whole-body images of patient with metastatic MTC 90 min (A) and 240 min (B) after intravenous injection of 740 MBq [99mTc]Demogastrin 2.

Tables

  • TABLE 1

    Analytic Data for Demogastrin Peptide-Conjugates

    PeptideFormulaMW/ES-MS (%)HPLC tR (min)
    System 1*System 2†System 3‡
    Demogastrin 1[N40,(D)Glu1]MG1,848.98/1,848.7 (100)18.014.827.4
    Demogastrin 2[N40–1,Gly0(D)Glu1]MG1,906.03/1,905.8 (100)18.917.927.2
    Demogastrin 3[N′40,(D)Glu1]MG§2,026.18/2,026.9 (100)19.818.628.1

    • ↵* System 1 = Machery–Nagel Nucleosil 120-3 C18 column eluted at a 0.75 mL/min flow rate with: 0 min 20% B, 20 min 40% B (A = 0.1% TFA in H2O, B = acetonitrile).

    • ↵† System 2 = XTerra RP-8 (5 μm, 4.6 × 150 mm) analytic cartridge column eluted at 1 mL/min with: 0%–40% B in 40 min (A and B as in system 1).

    • ↵‡ System 3 = Symmetry Shield RP18 (5 μm, 3.9 × 150 mm) analytic cartridge column eluted at 1 mL/min with: 0%–40% B in 40 min (A = 0.2% H3PO4 neutralized to pH 7 with 25% aq. NH3).

    • ↵§ N′4 = (H2NCH2CH2NHCH2)CH-(p-CH2C6H4)-NHCOCH2OCH2CO-.

    • MW = molecular weight; MG = minigastrin.

  • TABLE 2

    Analytic Data for (Radio)metallated Peptide-Conjugates

    PeptideFormulaMW MALDI-TOF (%, m/z)HPLC tR (min)
    System 2*System 3†
    [99mTc]Demogastrin 1[99mTc]2N40,(D)Glu1]MGnd16.727.1
    [ReV]Demogastrin 1[ReO2N40,(D)Glu1]MG2,065.916.0nd
    2,088.0 (100, [M+Na]+)
    [99mTc]Demogastrin 2[99mTcO2N40–1,Gly0(D)Glu1]MGnd20.826.9
    [ReV]Demogastrin 2[ReO2N40–1,Gly0(D)Glu1]MG2,123.020.2nd
    2,208.0 (100, [M+2Na+K]+)
    [99mTc]Demogastrin 3[99mTc]2N′40,(D)Glu1]MG‡nd21.327.6
    [ReV]Demogastrin 3[ReO2N′40,(D)Glu1]MG2,243.0§21.6nd
    2,242.0

    • ↵* System 2 = XTerra RP-8 (5 μm, 4.6 × 150 mm) analytic cartridge column eluted at 1 mL/min with: 0%–40% B in 40 min A (A = 0.1% TFA in H2O, B = acetonitrile).

    • ↵† System 3 = Symmetry Shield RP18 (5 μm, 3.9 × 150 mm) analytic cartridge column eluted at 1 mL/min with: 0%–40% B in 40 min (A = 0.2% H3PO4 neutralized to pH 7 with 25% aq. NH3).

    • ↵‡ N′4 = (H2NCH2CH2NHCH2)CH-(p-CH2C6H4)-NHCOCH2OCH2CO-.

    • ↵§ ES-MS spectra were conducted.

    • MW = molecular weight; MG = minigastrin; nd = not done.

  • TABLE 3

    Biodistribution Data of [99mTc]Demogastrin 1–3 in AR4-2J Tumor-Bearing Athymic Mice as %ID/g Tissue (Mean ± SD)

    Organ[99mTc]Demogastrin 1[99mTc]Demogastrin 2[99mTc]Demogastrin 3
    1 h pi4 h pi1 h pi4 h pi1 h pi
    Blood0.36 ± 0.100.15 ± 0.010.17 ± 0.020.03 ± 0.000.35 ± 0.06
    Liver0.34 ± 0.051.04 ± 0.090.63 ± 0.200.38 ± 0.032.61 ± 0.49
    Heart0.15 ± 0.040.09 ± 0.020.30 ± 0.180.04 ± 0.000.28 ± 0.06
    Kidneys78.97 ± 1.6041.08 ± 4.2183.92 ± 14.4542.65 ± 4.1878.18 ± 11.85
    Blocked kidneys17.78 ± 0.07†20.95 ± 1.27*27.95 ± 6.49*14.03 ± 1.84†19.50 ± 3.84*
    Stomach6.59 ± 0.503.47 ± 0.235.86 ± 0.283.96 ± 0.265.96 ± 0.49
    Blocked stomach1.06 ± 0.08†0.45 ± 0.17†0.43 ± 0.01†0.16 ± 0.03†0.41 ± 0.10†
    Intestine0.62 ± 0.191.07 ± 0.160.44 ± 0.020.54 ± 0.040.37 ± 0.03
    Spleen0.17 ± 0.020.22 ± 0.400.13 ± 0.030.10 ± 0.010.33 ± 0.09
    Muscle0.12 ± 0.050.09 ± 0.000.09 ± 0.070.02 ± 0.010.12 ± 0.05
    Lung0.37 ± 0.050.18 ± 0.020.54 ± 0.290.06 ± 0.010.45 ± 0.09
    Pancreas0.28 ± 0.050.13 ± 0.010.22 ± 0.100.09 ± 0.020.23 ± 0.02
    AR4-2J tumor6.13 ± 3.282.70 ± 1.125.50 ± 0.852.88 ± 0.424.20 ± 1.22
    Blocked tumor0.94 ± 0.42*0.34 ± 0.01*0.45 ± 0.07†0.17 ± 0.00†0.52 ± 0.11*

    • Student t test was used for statistical analysis; a P value of <0.01 (

    • ↵* P) was considered very significant, whereas a P value of <0.001 (

    • ↵† P) was considered extremely significant.

    • pi = after injection.

      Results are average of 4 animals per group. Blocking was achieved by coinjection of 250 μg [(D)Glu1]minigastrin.

  • TABLE 4

    Tumor-to-Background Ratios After Injection of [99mTc]Demogastrin 1–3 in AR4-2J Tumor-Bearing Mice

    Organ[99mTc]Demogastrin 1[99mTc]Demogastrin 2[99mTc]Demogastrin 3
    1 h pi4 h pi1 h pi4 h pi1 h pi
    Tumor/blood1718329612
    Tumor/liver183982
    Tumor/muscle51306114435
    Tumor/blocked tumor6812178

    • pi = after injection.

Back to top

In this issue

Print
Download PDF
Article Alerts
Email Article
Citation Tools
Bookmark this article

Jump to section