University of Veterinary Medicine Hannover, Hannover, Germany.
BMC Cancer. 2012 Jul 11;12:284. doi: 10.1186/1471-2407-12-284.
Cell lines represent a key tool in cancer research allowing the generation of neoplasias which resemble initial tumours in in-vivo animal models. The characterisation of early tumour development is of major interest in order to evaluate the efficacy of therapeutic agents. Magnetic resonance imaging (MRI) based in-vivo characterisation allows visualisation and characterisation of tumour development in early stages prior to manual palpation. Contrast agents for MRI such as superparamagnetic iron oxide nanoparticles (SPIOs) and manganese chloride (MnCl2) represent powerful tools for the in-vivo characterisation of early stage tumours. In this experimental study, we labelled prostate cancer cells with MnCl2 or SPIOs in vitro and used 1 T MRI for tracing labelled cells in-vitro and 7 T MRI for tracking in an in-vivo animal model.
Labelling of prostate cancer cells CT1258 was established in-vitro with MnCl2 and SPIOs. In-vitro detection of labelled cells in an agar phantom was carried out through 1 T MRI while in-vivo detection was performed using 7 T MRI after subcutaneous (s.c.) injection of labelled cells into NOD-Scid mice (n = 20). The animals were scanned in regular intervals until euthanization. The respective tumour volumes were analysed and corresponding tumour masses were subjected to histologic examination.
MnCl2in-vitro labelling resulted in no significant metabolic effects on proliferation and cell vitality. In-vitro detection-limit accounted 105 cells for MnCl2 as well as for SPIOs labelling. In-vivo 7 T MRI scans allowed detection of 103 and 104 cells. In-vivo MnCl2 labelled cells were detectable from days 4-16 while SPIO labelling allowed detection until 4 days after s.c. injection. MnCl2 labelled cells were highly tumourigenic in NOD-Scid mice and the tumour volume development was characterised in a time dependent manner. The amount of injected cells correlated with tumour size development and disease progression. Histological analysis of the induced tumour masses demonstrated characteristic morphologies of prostate adenocarcinoma.
To the best of our knowledge, this is the first study reporting direct in-vitro MnCl2 labelling and 7 T based in-vivo MRI tracing of cancer cells in a model of prostate cancer. MnCl2 labelling was found to be suitable for in-vivo tracing allowing long detection periods. The labelled cells kept their highly tumourigenic potential in-vivo. Tumour volume development was visualised prior to manual palpation allowing tumour characterisation in early stages of the disease.
细胞系是癌症研究的重要工具，可生成类似于体内动物模型中初始肿瘤的肿瘤。早期肿瘤发展的特征是评估治疗药物疗效的主要关注点。基于磁共振成像（MRI）的体内特征可以在手动触诊之前可视化和表征早期肿瘤的发展。MRI 用的造影剂，如超顺磁氧化铁纳米颗粒（SPIOs）和氯化锰（MnCl2），是用于早期肿瘤体内特征的有力工具。在这项实验研究中，我们在体外用 MnCl2 或 SPIOs 标记前列腺癌细胞，并用 1T MRI 进行体外标记细胞的跟踪，用 7T MRI 进行体内动物模型的跟踪。
在体外用 MnCl2 和 SPIOs 对前列腺癌细胞 CT1258 进行标记。通过 1T MRI 在琼脂体模中对标记细胞进行体外检测，通过皮下（s.c.）注射标记细胞到 NOD-Scid 小鼠后，用 7T MRI 进行体内检测（n=20）。动物每隔一段时间扫描，直到安乐死。分析相应的肿瘤体积，并对相应的肿瘤质量进行组织学检查。
MnCl2 体外标记对增殖和细胞活力没有显著的代谢影响。体外检测限为 105 个细胞，MnCl2 和 SPIOs 标记的细胞都可以检测到。体内 7T MRI 扫描可以检测到 103 和 104 个细胞。体内 MnCl2 标记的细胞可在第 4-16 天检测到，而 SPIO 标记的细胞可在注射后第 4 天检测到。MnCl2 标记的细胞在 NOD-Scid 小鼠中具有很强的致瘤性，肿瘤体积的发展呈时间依赖性。注射细胞的数量与肿瘤大小的发展和疾病的进展相关。诱导的肿瘤组织学分析显示出前列腺腺癌的特征形态。
据我们所知，这是首例报道直接在体外使用 MnCl2 标记和在体内使用 7T 基于 MRI 跟踪前列腺癌模型中癌细胞的研究。MnCl2 标记被发现适合于体内跟踪，允许长时间的检测。标记的细胞在体内保持其高度致瘤性。在手动触诊之前，可以观察到肿瘤体积的发展，从而在疾病的早期阶段对肿瘤进行特征化。
