Article Figures & Data
Figures
- FIGURE 1.
Influence of time and temperature on yield of 99mTc-His6-(ZHER2:4)2 obtained with IsoLink kit. [99mTc(CO)3(H2O)3]+ produced according to manufacturer's instructions was added to 48 μg of His6-(ZHER2:4)2 and incubated at 37°C, 50°C, 70°C, or 100°C. After 5, 10, 20, and 40 min of incubation, reaction mixture samples were analyzed by ITLC. Labeling yields are presented as mean from 2 independent samples ± maximum error.
- FIGURE 2.
Influence of labeling temperature on binding of 99mTc-His6-(ZHER2:4)2 to SK-OV-3 cells. Conjugate was labeled with 99mTc by use of IsoLink kit at 100°C, 70°C, and 50°C, and cell-bound fraction was measured when conjugate was added to HER2-expressing cells at conjugate-to-antigen ratio of 1:100. Data are presented as mean for 3 dishes ± SD. Addition of 1,000-fold excess of nonlabeled His6-(ZHER2:4)2 reduced cellular binding to less than 1% of added radioactivity in all samples.
- FIGURE 3.
Anterior whole-body images of representative BALB/c nu/nu mice with subcutaneous HER2-expressing SK-OV-3 human breast cancer xenografts. Images were obtained 6 h after injection of 125I-His6-(ZHER2:4)2 (left) and 99mTc-His6-(ZHER2:4)2 (right). Tumors (arrows) can be seen clearly.
Tables
Incubation medium Incubation time, h 99mTc radioactivity associated with 99mTc-His6- (ZHER2:4)2, %* PBS 2 99.1 ± 0.1 PBS 4 99.1 ± 0.1 PBS 6 99.0 ± 0.2 l-Cysteine (100-fold excess) 1 93.0 ± 1.0 l-Cysteine (500-fold excess) 1 88.0 ± 0.7 l-Cysteine (5,000-fold excess) 1 84.4 ± 0.3 l-Histidine (100-fold excess) 1 (37°C) 95.6 ± 0.0 l-Histidine (500-fold excess) 1 (37°C) 80.0 ± 4.0 l-Histidine (5,000-fold excess) 1 (37°C) 86.0 ± 3.0 ↵* Each value represents mean for 2 samples ± maximum error.
- TABLE 2
Biodistributions of 125I-His6-(ZHER2:4)2 and 99mTc-His6-(ZHER2:4)2 in Tumor-Bearing Mice
%IA/g of organ or tissue* 1 h 4 h 8 h 12 h Organ or tissue 125I 99mTc 125I 99mTc 125I 99mTc 125I 99mTc Blood 3.83 ± 0.29 1.16 ± 0.16 0.56 ± 0.14 (0.63 ± 0.09) 0.54 ± 0.04 (0.47 ± 0.14) 0.09 ± 0.03 0.54 ± 0.23 0.04 ± 0.01 0.40 ± 0.03 Heart 1.34 ± 0.12 0.70 ± 0.07 0.31 ± 0.14 (0.22 ± 0.02) 0.43 ± 0.04 (1.19 ± 0.20) 0.03 ± 0.02 0.58 ± 0.14 0.03 ± 0.01 NM Lungs 2.56 ± 0.10 1.18 ± 0.10 0.44 ± 0.12 (0.48 ± 0.06) 0.90 ± 0.04 (1.35 ± 0.04) 0.12 ± 0.04 1.22 ± 0.12 0.06 ± 0.02 NM Liver 5.10 ± 0.25 6.07 ± 0.42 1.00 ± 0.38 (1.06 ± 0.37) 6.97 ± 0.28 (7.38 ± 0.92) 0.09 ± 0.02 7.32 ± 3.21 0.04 ± 0.01 6.77 ± 0.53 Spleen 1.41 ± 0.10 1.27 ± 0.05 0.19 ± 0.04 (0.20 ± 0.03) 0.97 ± 0.05 (1.92 ± 0.30) 0.04 ± 0.01 1.59 ± 0.06 0.02 ± 0.01 NM Pancreas 2.43 ± 0.08 0.79 ± 0.09 0.26 ± 0.05 (0.44 ± 0.14) 0.62 ± 0.05 (1.01 ± 0.14) 0.04 ± 0.01 1.10 ± 0.49 0.01 ± 0.01 NM Kidneys 69 ± 10 92.53 ± 0.73 30 ± 3 (25 ± 4) 89 ± 10 (104 ± 17) 8.22 ± 2.19 79 ± 37 3.61 ± 0.86 75 ± 10 Stomach 2.26 ± 0.29 1.55 ± 0.19 0.76 ± 0.21 (0.81 ± 0.16) 1.76 ± 0.12 (1.96 ± 0.20) 0.33 ± 0.17 1.19 ± 0.38 0.05 ± 0.02 0.93 ± 0.12 Salivary glands 2.70 ± 0.53 1.63 ± 0.03 1.39 ± 0.31 (1.14 ± 0.13) 2.55 ± 0.29 (2.28 ± 0.21) 0.22 ± 0.06 1.20 ± 0.35 0.04 ± 0.02 1.20 ± 0.10 Tumor 3.23 ± 0.12 1.94 ± 0.58 2.27 ± 0.55 (0.53 ± 0.06) 2.61 ± 0.41 (1.47 ± 0.16) 1.06 ± 0.20 2.64 ± 0.86 0.68 ± 0.09 2.62 ± 0.48 Skin 3.31 ± 1.18 1.42 ± 0.19 0.27 ± 0.09 (0.80 ± 0.50) 1.69 ± 0.77 (1.94 ± 0.78) 0.12 ± 0.06 1.57 ± 0.25 0.03 ± 0.00 NM Muscle 0.84 ± 0.12 0.34 ± 0.06 0.07 ± 0.03 (0.10 ± 0.02) 0.32 ± 0.08 (0.50 ± 0.03) 0.01 ± 0.00 0.30 ± 0.07 NM NM Bone 0.56 ± 0.11 0.58 ± 0.16 0.08 ± 0.04 (0.20 ± 0.09) 0.55 ± 0.18 (2.54 ± 0.99) 0.04 ± 0.01 0.81 ± 0.34 0.04 ± 0.01 NM Thyroid 0.08 ± 0.03 0.05 ± 0.01 0.15 ± 0.07 (0.16 ± 0.02) 0.06 ± 0.01 (0.11 ± 0.01) 0.24 ± 0.08 0.03 ± 0.01 0.20 ± 0.04 0.03 ± 0.02 ↵* Each value represents mean for 4 animals ± SD. Values for thyroid are presented as percent injected radioactivity per organ. Values in parentheses are for 4 animals that were preinjected with large molar excess of nonlabeled dimer. NM = nonmeasurable.
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