整合素 αβ 靶向磁共振分子成像在异种移植小鼠乳腺癌模型中的应用。
Integrin αβ-targeted MR molecular imaging of breast cancer in a xenograft mouse model.
机构信息
Department of Diagnostic Radiology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No.17, Panjiayuan Nanli, Chaoyang District, Beijing, 100021, China.
GE Healthcare, Beijing, 100176, China.
出版信息
Cancer Imaging. 2021 Jun 29;21(1):44. doi: 10.1186/s40644-021-00411-9.
BACKGROUND
The motif RXDLXXL-based nanoprobes allow specific imaging of integrin αβ, a protein overexpressed during tumorigenesis and tumor progression of various tumors. We applied a novel RXDLXXL-coupled cyclic arginine-glycine-aspartate (RGD) nonapeptide conjugated with ultrasmall superparamagnetic iron oxide nanoparticles (referred to as cFK-9-USPIO) for the application of integrin αβ-targeted magnetic resonance (MR) molecular imaging for breast cancer.
METHODS
A novel MR-targeted nanoprobe, cFK-9-USPIO, was synthesized by conjugating integrin αβ-targeted peptide cFK-9 to N-amino (-NH2)-modified USPIO nanoparticles via a dehydration esterification reaction. Integrin αβ-positive mouse breast cancer (4 T1) and integrin αβ negative human embryonic kidney 293 (HEK293) cell lines were incubated with cFK-9-AbFlour 647 (blocking group) or cFK-9-USPIO (experimental group), and subsequently imaged using laser scanning confocal microscopy (LSCM) and 3.0 Tesla magnetic resonance imaging (MRI) system. The affinity of cFK-9 targeting αβ was analyzed by calculating the mean fluorescent intensity in cells, and the nanoparticle targeting effect was measured by the reduction of T2 values in an in vitro MRI. The in vivo MRI capability of cFK-9-USPIO was investigated in 4 T1 xenograft mouse models. Binding of the targeted nanoparticles to αβ-positive 4 T1 tumors was determined by ex vivo histopathology.
RESULTS
In vitro laser scanning confocal microscopy (LSCM) imaging showed that the difference in fluorescence intensity between the targeting and blocking groups of 4 T1 cells was significantly greater than that in HEK293 cells (P < 0.05). The in vitro MRI demonstrated a more remarkable T2 reduction in 4 T1 cells than in HEK293 cells (P < 0.001). The in vivo MRI of 4 T1 xenograft tumor-bearing nude mice showed significant T2 reduction in tumors compared to controls. Prussian blue staining further confirmed that αβ integrin-targeted nanoparticles were specifically accumulated in 4 T1 tumors and notably fewer nanoparticles were detected in 4 T1 tumors of mice injected with control USPIO and HEK293 tumors of mice administered cFK-9-USPIO.
CONCLUSIONS
Integrin αβ-targeted nanoparticles have great potential for use in the detection of αβ-overexpressed breast cancer with MR molecular imaging.
背景
基于 RXDLXXL 基序的纳米探针可特异性地对整合素 αβ 进行成像，整合素 αβ 在各种肿瘤的发生和进展中过度表达。我们应用了一种新型的 RXDLXXL 偶联的环精氨酸-甘氨酸-天冬氨酸（RGD）非肽与超顺磁性氧化铁纳米颗粒（简称 cFK-9-USPIO）偶联，用于整合素 αβ 靶向磁共振（MR）分子成像在乳腺癌中的应用。
方法
通过脱水酯化反应将整合素 αβ 靶向肽 cFK-9 偶联到 N-氨基（-NH2）修饰的 USPIO 纳米颗粒上，合成了一种新型的 MR 靶向纳米探针 cFK-9-USPIO。将整合素 αβ 阳性的小鼠乳腺癌（4T1）和整合素 αβ 阴性的人胚肾 293（HEK293）细胞系分别用 cFK-9-AbFlour 647（阻断组）或 cFK-9-USPIO（实验组）孵育，然后用激光扫描共聚焦显微镜（LSCM）和 3.0T 磁共振成像（MRI）系统进行成像。通过计算细胞内平均荧光强度分析 cFK-9 靶向 αβ 的亲和力，通过体外 MRI 中 T2 值的降低来测量纳米颗粒的靶向效果。在 4T1 异种移植小鼠模型中研究了 cFK-9-USPIO 的体内 MRI 能力。通过离体组织病理学确定靶向纳米颗粒与 αβ 阳性 4T1 肿瘤的结合。
结果
体外激光扫描共聚焦显微镜（LSCM）成像显示，4T1 细胞的靶向组与阻断组之间荧光强度的差异明显大于 HEK293 细胞（P<0.05）。体外 MRI 显示 4T1 细胞的 T2 降低比 HEK293 细胞更显著（P<0.001）。4T1 异种移植荷瘤裸鼠的体内 MRI 显示，与对照组相比，肿瘤的 T2 明显降低。普鲁士蓝染色进一步证实，αβ 整合素靶向纳米颗粒特异性地积聚在 4T1 肿瘤中，而在注射对照 USPIO 的 4T1 肿瘤和给予 cFK-9-USPIO 的 HEK293 肿瘤中检测到的纳米颗粒明显较少。
结论
整合素 αβ 靶向纳米颗粒具有用于 MR 分子成像检测 αβ 过表达乳腺癌的巨大潜力。
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