Synthesis and evaluation of novel Tc-99m labeled probestin conjugates for imaging APN/CD13 expression in vivo.
Synthesis and evaluation of novel Tc-99m labeled probestin conjugates for imaging APN/CD13 expression in vivo.
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DOI：
10.1021/bc200546b
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发表时间：
2012-01-18
影响因子：
4.7
通讯作者：
Gali, Hariprasad
中科院分区：
文献类型：
--
作者：
Pathuri, Gopal;Hedrick, Andria F.;Disch, Bryan C.;Doan, John T.;Ihnat, Michael A.;Awasthi, Vibhudutta;Gali, Hariprasad
已知氨肽酶N（APN，也称为CD 13）在肿瘤增殖、附着、血管生成和肿瘤侵袭中起重要作用。在这项研究中，我们假设，放射性标记的高亲和力APN抑制剂可能是潜在的有用的APN表达在体内成像。在这里，我们报告的合成，放射性标记，并含有三肽，N，N-二甲基甘氨酰-L-赖氨酰-L-半胱氨酰胺（N3 S），螯合剂的新probestin共轭物的生物学评价。采用固相多肽合成法合成了新型普罗布汀偶联物，经反相高效液相色谱纯化，电喷雾质谱表征。用Re（V）或99 mTc（V）葡萄糖酸盐合成子进行金属间化合物的金属间化合物转移反应，使它们与Re（V）和99 mTc（V）形成络合物。Re（V）O-N_3S-Probestin偶联物的质谱分析与中性Re（V）O-N_3S络合物的形成一致。通过使用完整HT-1080细胞进行体外APN酶测定确定的ReO-N3 S-Probestin缀合物的初始生物活性证明了比bestatin更高的APN酶活性抑制。在移植有HT-1080细胞来源的人纤维肉瘤肿瘤的裸鼠中进行的99 mTcO-N3 S-PEG 2-Probestin的体内生物分布和全身平面成像研究表明，在注射后1小时（p.i.），肿瘤摄取值为2.88 ± 0.64%ID/g，肿瘤与血液和肿瘤与肌肉的比率分别为4.8和5.3。在注射后1小时获得的全身平面图像中，肿瘤清晰可见，但当APN被过量的非放射性ReO-N3 S-PEG 2-Probestin缀合物的共注射竞争性阻断时，则没有。这些结果证明了使用高亲和力APN抑制剂缀合物作为体内靶向APN的靶向载体的可行性。
The enzyme aminopeptidase N (APN, also known as CD13) is known to play an important role in tumor proliferation, attachment, angiogenesis, and tumor invasion. In this study, we hypothesized that a radiolabeled high affinity APN inhibitor could be potentially useful for imaging APN expression in vivo. Here we report synthesis, radiolabeling, and biological evaluation of new probestin conjugates containing a tripeptide, N,N-dimethylglycyl-L-lysinyl-L-cysteinylamide (N3S), chelator. New probestin conjugates were synthesized by solid-phase peptide synthesis method, purified by reversed-phase HPLC, and characterized by electrospray mass spectrometry. The conjugates were complexed with Re(V) and 99mTc(V) by transmetallation using corresponding Re(V) or 99mTc(V) gluconate synthon. The mass spectral analyses of ReO-N3S-Probestin conjugates were consistent with the formation of neutral Re(V)O-N3S complexes. Initial biological activity of ReO-N3S-Probestin conjugates determined by performing an in vitro APN enzyme assay using intact HT-1080 cells demonstrated higher inhibition of APN enzyme activity than bestatin. In vivo biodistribution and whole body planar imaging studies of 99mTcO-N3S-PEG2-Probestin performed in nude mice xenografted with human fibrosarcoma tumors derived from HT-1080 cells demonstrated a tumor uptake value of 2.88 ± 0.64 %ID/g with tumor-to-blood and tumor-to-muscle ratios of 4.8 and 5.3 respectively at 1 hr post-injection (p.i.). Tumors were clearly visible in whole-body planar image obtained at 1 hr p.i., but not when the APN was competitively blocked with a co-injection of excess non-radioactive ReO-N3S-PEG2-Probestin conjugate. These results demonstrate the feasibility of using high affinity APN inhibitor conjugates as targeting vectors for in vivo targeting of APN.
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影响因子：
45.3
作者：
Gregorc, Vanesa;Zucali, Paolo A.;Bordignon, Claudio
通讯作者：
Bordignon, Claudio
影响因子：
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作者：
Cantorias, Melchor V.;Howell, Robertha C.;Francesconi, Lynn C.
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DIXON, J;KAKLAMANIS, L;GATTER, KC
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