Gazouli Maria, Bouziotis Penelope, Lyberopoulou Anna, Ikonomopoulos John, Papalois Apostolos, Anagnou Nicholas P, Efstathopoulos Efstathios P
Department of Basic Biological Science, Laboratory of Biology, School of Medicine, University of Athens, Athens, Greece 2nd Department of Radiology, Attikon University Hospital, Athens, Greece
Radiochemical Studies Laboratory, Institute of Nuclear and Radiological Sciences, Technology, Energy and Safety (I.N.Ra.S.T.E.S.) N.C.S.R. "Demokritos", Athens, Greece.
In Vivo. 2014 Nov-Dec;28(6):1091-5.
BACKGROUND/AIM: The basic role of vascular endothelial growth factor (VEGF) in cancer is underscored by the approval of bevacizumab for first-line treatment of cancer patients. Recent anticancer therapeutics based on active tumor targeting by conjugating tumor-specific antibodies has become of great interest in oncology. Current progress in nanomedicine has exploited the possibility of designing tumor-targeted nanocarriers able to deliver specific molecule payloads in a selective manner to improve the efficacy and safety of cancer imaging and therapy. We herein aimed to determine the targeting ability of bevacizumab-conjugated quantum dots (QDs) in vitro and in vivo.
We used QDs labeled with bevacizumab, in various in vitro experiments using cell lines derived from colorectal cancer (CRC) and breast cancer (BC). For a competition study of QD-bevacizumab complex and bevacizumab, the cells were pre-treated with bevacizumab (100 nmol/L) for 24 h before exposure to the QD-bevacizumab complex. The breast cancer cells (MDA-MB-231) were injected to 9 nude mice to make the xenograft tumor model. The QD-bevacizumab complex was injected into the tumor model and fluorescence measurements were performed at 1, 12, and 24 h post-injection.
Immunocytochemical data confirmed strong and specific binding of the QD-bevacizumab complex to the cell lines. The cells pre-treated with an excess of bevacizumab showed absence of QD binding. The in vivo fluorescence image disclosed that there was an increased signal of tumor after the injection of QDs. Ex vivo analysis showed 3.1 ± 0.8%, 28.6 ± 5.4% and 30.8 ± 4.2% injected dose/g accumulated in the tumors at 1, 12 and 24 h respectively. Tumor uptake was significantly decreased in the animals pretreated with excess of bevacizumab (p=0.001).
In conclusion, we could successfully detect the VEGF-expressing tumors using QDs-bevacizumab nanoprobes in vitro and in vivo, opening new perspectives for VEGF-targeted non-invasive imaging in clinical practice.
背景/目的：贝伐单抗被批准用于癌症患者的一线治疗，这突出了血管内皮生长因子（VEGF）在癌症中的基本作用。最近，通过偶联肿瘤特异性抗体实现主动肿瘤靶向的抗癌疗法在肿瘤学领域引起了极大的兴趣。纳米医学的当前进展利用了设计肿瘤靶向纳米载体的可能性，这些纳米载体能够以选择性方式递送特定分子载荷，以提高癌症成像和治疗的疗效及安全性。我们在此旨在确定贝伐单抗偶联量子点（QDs）在体外和体内的靶向能力。
我们使用用贝伐单抗标记的量子点，在源自结直肠癌（CRC）和乳腺癌（BC）的细胞系的各种体外实验中。为了进行量子点-贝伐单抗复合物与贝伐单抗的竞争研究，在暴露于量子点-贝伐单抗复合物之前，将细胞用贝伐单抗（100 nmol/L）预处理24小时。将乳腺癌细胞（MDA-MB-231）注射到9只裸鼠中以建立异种移植肿瘤模型。将量子点-贝伐单抗复合物注射到肿瘤模型中，并在注射后1、12和24小时进行荧光测量。
免疫细胞化学数据证实了量子点-贝伐单抗复合物与细胞系的强烈且特异性结合。用过量贝伐单抗预处理的细胞显示没有量子点结合。体内荧光图像显示注射量子点后肿瘤信号增强。离体分析显示在1、12和24小时时分别有3.1±0.8%、28.6±5.4%和30.8±4.2%的注射剂量/克积聚在肿瘤中。用过量贝伐单抗预处理的动物的肿瘤摄取显著降低（p = 0.001）。
总之，我们能够在体外和体内使用量子点-贝伐单抗纳米探针成功检测表达VEGF的肿瘤，为临床实践中VEGF靶向的非侵入性成像开辟了新的前景。
