Trifunctional<sup>99m</sup>Tc based radiopharmaceuticals: metal-mediated conjugation of a peptide with a nucleus targeting intercalator
作者:Karel Zelenka、Lubor Borsig、Roger Alberto
DOI:10.1039/c0ob00504e
日期:——
The development of molecular imaging agents with multiple functions has become a major trend in radiopharmaceutical chemistry. We present herein the syntheses of trifunctional compounds, combining an acridine orange (AO) based intercalator with a GRP receptor specific bombesin like peptide (BBN). Metal-mediated conjugation of these two functions via the [2 + 1] approach to the third function, the [M(CO)3]+ (M = 99mTc, Re) moiety, yielded the final trifunctional molecules. The strongly fluorescent acridine orange, a nuclear targeting agent, has been derivatised with 4-imidazolecarboxylate as a bidentate ligand and bombesin with an isonitrile group as a monodentate ligand. For cell and nuclear uptake studies, [Re(L1-BBN)(L2-Ical)(CO)3] type complexes were synthesized and characterized. For radiopharmaceutical purposes, the 99mTc analogues have been prepared in a stepwise synthesis. Fluorescence microscopy studies on PC-3 cells, bearing the BBN receptor, showed high and rapid uptake into the cytoplasm. For the bifunctional molecule, lacking the BBN peptide, no internalization was observed.
多功能分子成像剂的发展已成为放射性药物化学的主要趋势。本文介绍了三功能化合物的合成,这些化合物结合了以吖啶橙(AO)为基础的插入剂和GRP受体特异性类似bombesin的肽(BBN)。通过[2 + 1]方法,将这两种功能与第三种功能[M(CO)3]+(M = 99mTc,Re)部分进行金属介导的连接,得到了最终的三功能分子。作为核靶向剂,吖啶橙具有强烈的荧光,衍生化为双齿配体4-咪唑羧酸酯,bombesin则带有异氰基作为单齿配体。为了研究细胞和核摄取,我们合成了并表征了[Re(L1-BBN)(L2-Ical)(CO)3]型配合物。为了放射性药物的目的,我们采用逐步合成法合成了99mTc类似物。对携带BBN受体的PC-3细胞进行荧光显微镜研究,结果显示细胞质中的摄取率高且迅速。对于缺乏BBN肽的双功能分子,未观察到内化现象。