肿瘤新生血管超声分子靶向成像研究进展

在肿瘤间质中新生微血管内皮分子遗传学和微血管构筑的异质性是近年来研究的热点,也是肿瘤血管生成超声分子靶向成像的研究基础。文章对肿瘤血管生成超声分子靶向成像机制和研究进展进行综述。     

妇科肿瘤的血管形成和抗血管形成治疗研究进展

肿瘤的生长和转移需要新生血管提供血液,抗肿瘤血管形成是一种新的抗肿瘤策略。本文对妇科肿瘤领域中有关肿瘤微血管密度的检测及其预后价值、肿瘤组织血管形成活性分子的检测、血清血管形成分子的检测、抗肿瘤血管形成治疗尝试及其在妇科肿瘤治疗中的地位等问题进行了综述。     

DLL4与血管生成的关系

血管生成是胚胎发育和肿瘤生长的重要因素.多项研究发现,参与Notch信号的Delta配体4(Delta-like ligand 4,DLL4)能抑制新生血管分支生成,促进新生血管的成熟.阻断DLL4可增加无功能性新生血管的数量,从而抑制肿瘤生长,这为肿瘤抗血管生成疗法提供了新的策略,使DLL4有可能成为肿瘤治疗的新靶点.     

VEGF/VEGFR信号转导通路在肝癌靶向治疗中的研究进展

肝细胞肝癌(Hepatocellular Carcinoma,HCC,简称肝癌)是典型的多血供恶性肿瘤,肝癌细胞的生长、转移、侵袭都依赖新生血管的形成.血管内皮细胞生长因子(Vascular endothelial growth factor,VEGF)及其受体(Vascular endothelial growth factor receptor,VEGFR)的信号转导通路的活化可刺激血管内皮细胞增殖、迁移、在肝癌血管生成并促进肿瘤生长和转移中发挥了重要作用. Folkman首先提出"肿瘤生长是血管依赖性的",并认为肿瘤血管新生是由肿瘤血管生长因子(Tumor angiogenesis factor,TAF)所引起的,从而提出了"抑制血管生成而抑制肿瘤生长的假说".     

血管新生与疾病

很多疾病均伴有血管的变化。血管 ,特别是微血管 ,常与组织、器官的生长、发育和功能密切相关。疾病时它们发生相应的改变。有些疾病的发生发展和治疗与微血管新生有密切的联系 ,治疗时要抑制血管新生 ,如肿瘤等 ;有些疾病的发生发展有微血管的闭塞和退化 ,治疗时要促进微血管新生 ,如血栓性疾病等。因此近年来血管新生与疾病的关系在整体、细胞和分子水平上开展了广泛的研究 ,下面作一简要介绍。１肿瘤的血管新生与抗血管新生治疗１．１肿瘤血管新生肿瘤是人体细胞异常分化增殖的恶性疾病。肿瘤在表现其生长、转移等生物学行为时与其中的微…     

肿瘤血管生成和抗血管生成治疗的研究进展

肿瘤组织中的新生血管是保证肿瘤持续生长所必需的,也是肿瘤转移的重要途径之一.针对促进肿瘤血管生成和血管生成抑制物制定新策略,采用合适手段与方法,抑制肿瘤内血管新生,消除或减少肿瘤内原有血管,可达到治愈肿瘤的目的.     

适用于三维微血管成像的定量分析方法

目的 随着高分辨率三维成像技术的发展,微血管成像已成为临床诊断和实验研究的重要手段.为了在定性观察的基础上定量分析血管形态,本文提出一套完整的图像处理方法,并基于此设计了包括血管分割、血管细化、定量分析在内的血管形态分析流程.方法 首先利用数学形态学方法实现血管结构提取,接着给出计算血管密度、直径等指标的方法,并引入血管的“卷曲度”参数,以衡量血管的扭曲或异常程度.结果 将上述方法应用于1个肝脏血管和3个肿瘤血管灌注成像实例,统计各项形态指标,发现肝脏血管和肿瘤血管在血管密度、分支结构、直径分布以及卷曲度方面均有较大不同.结论 本文方法可有效定量三维血管结构,不仅能够定量较为规则的肝脏血管的形态特征,而且对于尺寸更小、结构更精细的肿瘤血管也能准确地定量分析,因此可以为肿瘤的早期诊断和药物治疗的效果追踪提供重要依据.     

靶向性抗癌蛋白色素上皮衍生因子在肿瘤中的研究进展

在肿瘤靶向治疗研究中,抗血管生成治疗是近十年来的一个研究热点.目前已有许多血管生成抑制剂应用于临床试验中.色素上皮衍生因子(PEDF)是一个能有效抑制新生血管形成的蛋白,与血管内皮生长因子(VEGF)等共同调控新生血管的发生过程.PEDF表达和抑制肿瘤生长、减少转移、良好的预后相关,对PEDF的深入研究有助于发挥其在肿瘤治疗中的作用.     

肿瘤治疗的新途径-抗肿瘤血管生成的生化和基因治疗

新生血管对于肿瘤的生长、浸润和转移有重要意义.体积超过1mm3～2mm3的肿瘤不仅需要新生血管维持营养供给和排泄代谢产物,还需要提供有利于转移的通道.新生血管形成包括内皮细胞的激活、增殖、迁移、血管基底膜的破坏、血管和血管网的形成,以及先前存在的血管网的连接等过程.抑制新生血管的生成可使肿瘤细胞进入休眠状态并诱导其凋亡.目前用抗血管生成来达到对肿瘤的治疗目的已不再是理论上的可能,而是一个渐趋成熟、实用的治疗方法.我们仅就此作一简要介绍.     

内皮抑制素的研究进展

肿瘤生长依赖新生血管的形成。通过抑制血管内皮细胞 ,切断肿瘤生长所需的营养途径 ,阻断新生血管形成 ,从而达到抑制肿瘤生长的目的。 Endostatin(内皮抑制素 )具有抑制肿瘤血管生成和肿瘤转移最强烈、最特异的生物学活性 ,且不产生耐药 ,是目前发现最为理想的血管生成抑制因子     

Inhibition of tumor growth and vasculature and fluorescence imaging using functionalized ruthenium-thiol protected selenium nanoparticles

Here we reported the high tumor targeting efficacy of luminescent Ru(II)-thiols protected selenium nanoparticles (Ru-MUA@Se). We have shown that a dual-target inhibitor Ru-MUA@Se directly suppress the tumor growth but also block blood-vessel growth. We also determined that the nanoparticles entered the cells via clathrin-mediated endocytosis pathway. In a xenograft HepG2 tumor model, we found that Ru-MUA@Se effectively inhibited tumor angiogenesis and suppressed tumor growth with low side effects using metronomic chemotherapy with Ru-MUA@Se. In vivo investigation of nanoparticles on nude mice bearing HepG2 cancer xenografts confirmed that Ru-MUA@Se nanoparticles possessed high tumor-targeted fluorescence imaging, exhibited enhanced antitumor efficacy and decreased systemic toxicity. Moreover, Ru-MUA@Se not only significantly induced dose-dependent disruption of mitochondrial membrane potential in HepG2 cells after 24 h treatment, but it also enhanced reactive oxygen species (ROS) generation. Our results suggest that the potential application of these Ru-MUA@Se nanoparticles in targeting cancer imaging and chemotherapy.     

裸鼠胃癌模型的相位衬度微血管成像

目的肿瘤血管生成与肿瘤的发生、发展等各个环节密切相关,并显著影响肿瘤的生物学行为和预后。本研究的目的在于使用相位衬度成像技术三维地、全面地观察肿瘤微血管形态。方法使用原位接种肿瘤组织块方法,建立裸鼠胃癌原位模型。实验样本分为正常组和肿瘤组。对得到的相位衬度图像进行增强、血管分割、三维重建,并且计算三维微血管密度参数。结果相位衬度成像可显示胃癌组织的微血管形态。对照组微血管密度低于胃癌组的肿瘤表面区域(P0.001),证明肿瘤微血管更加丰富。结论相位衬度成像可以更全面地显示肿瘤微血管的生成情况,有助于对胃癌的恶性程度、转移潜力等进行评估,并对治疗方案的选择、判断预后和评估抗肿瘤血管药物疗效具有重要意义。     

影像学评价大鼠胶质瘤及其微环境的研究进展

胶质瘤动物模型的建立对了解肿瘤的发生、发展及转归发挥着不可或缺的作用,而影像学作为一种无创手段,不仅可以对肿瘤进行宏观显像,而且可以对肿瘤微观结构及微环境改变进行定性定量评估。本文就影像学在评估大鼠胶质瘤肿瘤血管生成与抗血管生成、肿瘤乏氧状态、肿瘤微观结构及治疗后改变的研究现状进行综述,并归纳了不同成像方式的参数与肿瘤病理组织之间的相关性,总结了不同成像方式的优势,为影像学在胶质瘤诊治中的应用提供原理支持,同时为临床诊治胶质瘤提供新思路。     

Molecular imaging for assessment of mesenchymal stem cells mediated breast cancer therapy

The tumor tropism of mesenchymal stem cells (MSCs) makes them an excellent delivery vehicle used in anticancer therapy. However, the exact mechanisms of MSCs involved in tumor microenvironment are still not well defined. Molecular imaging technologies with the versatility in monitoring the therapeutic effects, as well as basic molecular and cellular processes in real time, offer tangible options to better guide MSCs mediated cancer therapy. In this study, an in situ breast cancer model was developed with MDA-MB-231 cells carrying a reporter system encoding a double fusion (DF) reporter gene consisting of firefly luciferase (Fluc) and enhanced green fluorescent protein (eGFP). In mice breast cancer model, we injected human umbilical cord-derived MSCs (hUC-MSCs) armed with a triple fusion (TF) gene containing the herpes simplex virus truncated thymidine kinase (HSV-ttk), renilla luciferase (Rluc) and red fluorescent protein (RFP) into tumor on day 13, 18, 23 after MDA-MB-231 cells injection. Bioluminescence imaging of Fluc and Rluc provided the real time monitor of tumor cells and hUC-MSCs simultaneously. We found that tumors were significantly inhibited by hUC-MSCs administration, and this effect was enhanced by ganciclovir (GCV) application. To further demonstrate the effect of hUC-MSCs on tumor cells in vivo, we employed the near infrared (NIR) imaging and the results showed that hUC-MSCs could inhibit tumor angiogenesis and increased apoptosis to a certain degree. In conclusion, hUC-MSCs can inhibit breast cancer progression by inducing tumor cell death and suppressing angiogenesis. Moreover, molecular imaging is an invaluable tool in tracking cell delivery and tumor response to hUC-MSCs therapies as well as cellular and molecular processes in tumor.     

量子点探针辅助的近红外荧光成像技术在肿瘤显影中的应用

肿瘤早期检测是精准并高效诊疗癌症的关键因素。荧光成像技术凭借其高灵敏度、高时空分辨率、无电离辐射和无创实时成像等优点,在生物医学领域,尤其在肿瘤检测方面展现出了广泛的应用前景。近红外光穿过生物组织时,受到的吸收和散射较少,因此在生物成像方面体现了高信噪比和强组织穿透能力。在众多荧光探针中,近红外发光的量子点探针因其量子产率高、抗光漂白性强、发射光可调和稳定性良好等特点在荧光成像方面显示出突出的优势。本文基于量子点探针的近红外荧光成像技术在肿瘤显影中的应用,介绍了量子点优异的光学性能,并重点讨论了硫化铅（PbS）和硫化银（Ag2S）近红外发光量子点探针在肿瘤成像方面的研究进展,并对近红外发光量子点探针的应用前景进行了展望。     

Optical imaging of cancer metastasis to bone marrow: a mouse model of minimal residual disease

The development of novel anti-cancer strategies requires more sensitive and less invasive methods to detect and monitor in vivo minimal residual disease in cancer models. Bone marrow metastases are indirectly detected by radiography as osteolytic and/or osteosclerotic lesions. Marrow micrometastases elude radiographic detection and, therefore, more sensitive methods are needed for their direct identification. Injection of cancer cells into the left cardiac ventricle of mice closely mimics micrometastatic spread. When luciferase-transfected cells are used, whole-body bioluminescent reporter imaging can detect microscopic bone marrow metastases of approximately 0.5 mm(3) volume, a size below the limit in which tumors need to induce angiogenesis for further growth. This sensitivity translates into early detection of intramedullary tumor growth, preceding the appearance of a radiologically evident osteolysis by approximately 2 weeks. Bioluminescent reporter imaging also enables continuous monitoring in the same animal of growth kinetics for each metastatic site and guides end-point analyses specifically to the bones affected by metastatic growth. This model will accelerate the understanding of the molecular events in metastasis and the evaluation of novel therapies aiming at repressing initial stages of metastatic growth.     

Color Doppler imaging and angiogenesis in ovarian tumors

The detection and assessment of ovarian lesions are an important part of gynecological practice. Advance knowledge of whether an overt ovarian mass is malignant may be useful for improving the effectiveness of surgical treatment. Pelvic ultrasonography has been developed continuously, and (in conjunction with biochemical and genetic markers) is being used to achieve these objectives with increasing accuracy. At the same time, knowledge is being accrued about the relationship between ultrasound-derived indices of ovarian tumor vascularity and the molecular aspects of angiogenesis. There is now the exciting prospect that color Doppler imaging with pulsed Doppler spectral analysis could also be used to monitor the development and intermediate effectiveness of novel anticancer treatment.     

Ultrasound molecular imaging of tumor angiogenesis with a neuropilin-1-targeted microbubble

Ultrasound molecular imaging has great potential to impact early disease diagnosis, evaluation of disease progression and the development of target-specific therapy. In this paper, two neuropilin-1 (NRP) targeted peptides, CRPPR and ATWLPPR, were conjugated onto the surface of lipid microbubbles (MBs) to evaluate molecular imaging of tumor angiogenesis in a breast cancer model. Development of a molecular imaging agent using CRPPR has particular importance due to the previously demonstrated internalizing capability of this and similar ligands. In vitro, CRPPR MBs bound to an NRP-expressing cell line 2.6 and 15.6 times more than ATWLPPR MBs and non-targeted (NT) MBs, respectively, and the binding was inhibited by pretreating the cells with an NRP antibody. In vivo, the backscattered intensity within the tumor, relative to nearby vasculature, increased over time during the ∼6 min circulation of the CRPPR-targeted contrast agents providing high contrast images of angiogenic tumors. Approximately 67% of the initial signal from CRPPR MBs remained bound after the majority of circulating MBs had cleared (8 min), 8 and 4.5 times greater than ATWLPPR and NT MBs, respectively. Finally, at 7–21 days after the first injection, we found that CRPPR MBs cleared faster from circulation and tumor accumulation was reduced likely due to a complement-mediated recognition of the targeted microbubble and a decrease in angiogenic vasculature, respectively. In summary, we find that CRPPR MBs specifically bind to NRP-expressing cells and provide an effective new agent for molecular imaging of angiogenesis.     

Bioluminescent imaging (BLI) to improve and refine traditional murine models of tumor growth and metastasis

Bioluminescent imaging (BLI) permits sensitive in vivo detection and quantification of cells specifically engineered to emit visible light. Three stable human tumor cell lines engineered to express luciferase were assessed for their tumorigenicity in subcutaneous, intravenous and spontaneous metastasis models. Bioluminescent PC-3M-luc-C6 human prostate cancer cells were implanted subcutaneously into SCID-beige mice and were monitored for tumor growth and response to 5-FU and mitomycin C treatments. Progressive tumor development and inhibition/regression following drug treatment were observed and quantified in vivo using BLI. Imaging data correlated to standard external caliper measurements of tumor volume, but bioluminescent data permitted earlier detection of tumor growth. In a lung colonization model, bioluminescent A549-luc-C8 human lung cancer cells were injected intravenously and lung metastases were monitored in vivo by whole animal imaging. Anesthetized mice were imaged weekly allowing a temporal assessment of in vivo lung tumor growth. This longitudinal study design permitted an accurate, real-time evaluation of tumor burden in the same animals over time. End-point bioluminescence measured in vivo correlated to total lung weight at necropsy. For a spontaneous metastatic tumor model, bioluminescent HT-29-luc-D6 human colon cancer cells implanted subcutaneously produced metastases to lung and lymph nodes in SCID-beige mice. Both primary tumors and micrometastases were detected by BLI in vivo. Ex vivo imaging of excised lung lobes and lymph nodes confirmed the in vivo signals and indicated a slightly higher frequency of metastasis in some mice. Levels of bioluminescence from in vivo and ex vivo images corresponded to the frequency and size of metastatic lesions in lungs and lymph nodes as subsequently confirmed by histology. In summary, BLI provided rapid, non-invasive monitoring of tumor growth and regression in animals. Its application to traditional oncology animal models offers quantitative and sensitive analysis of tumor growth and metastasis. The ability to temporally assess tumor development and responses to drug therapies in vivo also improves upon current standard animal models that are based on single end point data.     

High‐resolution MRI analysis of breast cancer xenograft on the chick chorioallantoic membrane

The chick chorioallantoic membrane (CAM) model has been successfully used to study angiogenesis, cancer progression and its pharmacological treatment, tumor pharmacokinetics, and properties of novel nanomaterials. MRI is an attractive technique for non‐invasive and longitudinal monitoring of physiological processes and tumor growth. This study proposes an age‐adapted cooling regime for immobilization of the chick embryo, enabling high‐resolution MRI of the embryo and the CAM tumor xenograft. 64 chick embryos were enrolled in this study. The novel immobilization and imaging protocol was optimized in 29 embryos. From d7 to d18 immobilization of the embryo up to 90 min was achieved by cooling at 4 °C pre‐imaging, with cooling times adapted to age. Its application to tumor growth monitoring was evaluated in 15 embryos after xenotransplantation of human MDA‐MB‐231 breast cancer cells on CAM. Tumor volumes were monitored from d4 to d9 after grafting (d11 to d16 after incubation) applying a T₂‐weighted multislice RARE sequence. At d9 after grafting, the tumors were collected and compared with the MRI‐derived data by histology and weight measurements. Additional imaging methods comprising DWI, T₂ mapping, and the bio‐distribution of contrast agents were tested at d9 after grafting in 20 further embryos. With the adaptive cooling regime, motion artifacts could be completely avoided for up to 90 min scan time, enabling high‐resolution in ovo imaging. Excellent anatomical details could be obtained in the embryo and tumors. Tumor volumes could be quantified over time. The results prove the feasibility of high‐resolution MRI for longitudinal tumor and organ growth monitoring. The suggested method is promising for future applications such as testing tailored and/or targeted treatment strategies, longitudinal monitoring of tumor development, analysis of therapeutic efficacies of drugs, or assessment of tumor pharmacokinetics. The method provides an alternative to animal experimentation. Copyright © 2015 John Wiley & Sons, Ltd.