Development of a peptide by phage display for SPECT imaging of resistance-susceptible breast cancer.
Development of a peptide by phage display for SPECT imaging of resistance-susceptible breast cancer.
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发表时间：
2014-08
影响因子：
2.5
通讯作者：
B. Larimer;S. Deutscher
中科院分区：
文献类型：
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作者：
B. Larimer;S. Deutscher
个性化医疗是癌症诊断和治疗的前沿。分子靶向治疗如曲妥珠单抗和他莫昔芬分别改善了表达ERBB2和雌激素受体的癌症患者的预后。靶向治疗的一个障碍是耐药性的发展。一种可以区分耐药易感癌症的靶向肽将有助于治疗。BT-474人乳腺癌细胞可能对他莫昔芬和曲妥珠单抗都有耐药性，并且可能作为靶向治疗可能无效的恶性肿瘤的模型。噬菌体（噬菌体）展示是一种组合技术，用于分离针对特定癌症亚型的肽。假设体内噬菌体展示可用于选择用于BT-474人乳腺癌异种移植物SPECT成像的肽。随机选取15个氨基酸肽的噬菌体文库进行4轮筛选，然后对14个克隆进行BT-474的结合和特异性分析。一个噬菌体克隆，51，表现出良好的结合和特异性，并合成了所显示的肽进行体外鉴定。肽51与BT-474细胞特异性结合，EC50 = 2.33µM，合成为dota偶联肽，并用（111）In进行放射性标记，用于体外和体内分析。对BT-474细胞的IC50值为16.1 nM，分析了其在BT-474移植小鼠体内的生物分布和SPECT成像。虽然肿瘤摄取适中，为0.11% ID/g，但SPECT成像显示明显的肿瘤血管结合模式。研究发现，肽51与肽V1具有相同的5个氨基酸n端序列，后者与肿瘤脉管蛋白Nrp1结合。检测肽51和V1与靶细胞的结合情况，51与靶细胞和内皮细胞均结合，而V1仅与内皮细胞结合。51的截断版本没有结合BT-474细胞，表明51的靶向能力独立于同源V1序列。这些结果表明，体内噬菌体展示可以有效地识别特异性靶向乳腺癌细胞系的肽，该细胞系易受靶向治疗耐药性的影响。
Personalized medicine is at the forefront of cancer diagnosis and therapy. Molecularly targeted therapies such as trastuzumab and tamoxifen have enhanced prognosis of patients with cancers expressing ERBB2 and the estrogen receptor, respectively. One obstacle to targeted therapy is the development of resistance. A targeted peptide that could distinguish resistance-susceptible cancer would aid in treatment. BT-474 human breast cancer cells can be resistant to both tamoxifen and trastuzumab, and may serve as a model for malignancies in which targeted therapy may not work. Bacteriophage (phage) display is a combinatorial technology that has been used to isolate peptides that target a specific cancer subtype. It was hypothesized that in vivo phage display could be used to select a peptide for SPECT imaging of BT-474 human breast cancer xenografts. A phage library displaying random 15 amino acid peptides was subjected to four rounds of selection, after which 14 clones were analyzed for BT-474 binding and specificity. One phage clone, 51, demonstrated superior binding and specificity, and the displayed peptide was synthesized for in vitro characterization. Peptide 51 bound specifically to BT-474 cells with an EC50 = 2.33 µM and was synthesized as a DOTA-conjugated peptide and radiolabeled with (111)In for in vitro and in vivo analysis. The radiolabeled peptide exhibited an IC50 = 16.1 nM to BT-474 cells and its biodistribution and SPECT imaging in BT-474 xenografted mice was analyzed. Although tumor uptake was moderate at 0.11% ID/g, SPECT imaging revealed a distinct tumor vasculature binding pattern. It was discovered that peptide 51 had an identical 5 amino acid N-terminal sequence to a peptide, V1, which bound to Nrp1, a tumor vasculature protein. Peptide 51 and V1 were examined for binding to target cells, and 51 bound both target and endothelial cells, while V1 only bound endothelial cells. Truncated versions of 51 did not bind BT-474 cells, demonstrating that the targeting ability of 51 was independent of the homologous V1 sequence. These results demonstrate that in vivo phage display can effectively identify a peptide that specifically targets a breast cancer cell line that is susceptible to targeted therapy resistance.