Chambers A F, Schmidt E E, MacDonald I C, Morris V L, Groom A C
Department of Oncology, University of Western Ontario, London, Canada.
J Natl Cancer Inst. 1992 May 20;84(10):797-803. doi: 10.1093/jnci/84.10.797.
There are few techniques that permit direct observation of tumor metastasis. The ability to observe steps in this process as they occur in experimental animals would complement studies on molecular mechanisms.
We have developed a novel procedure using high-resolution intravital videomicroscopy to permit direct observation of cells as they arrest in the microcirculation, extravasate, and form micrometastases. We used this procedure to study early steps in experimental metastasis in immune-deficient chick embryos, permitting us to develop this technique in a relatively accessible respiratory organ and in the absence of host immune responses. Our goals were to develop techniques applicable to this host and to other hosts and to clarify the process of hematogenous tumor spread in this host.
We injected fluorescently labeled B16F1 melanoma cells into the circulation of 11- to 13-day chick embryos, and using intravital videomicroscopy, we observed the cells in the chorioallantoic membrane over time.
The majority of injected cells were trapped initially in orifices to the chorioallantoic membrane capillary plexus or in tapering ends of arterioles leading to the plexus. During the first 2 hours, cells were found only in vessel lumina. After 8 hours, 83% of cells had extravasated, and the rest were in the process of extravasation. Cell shape changes and pseudopodial extensions were seen during extravasation and tumor development. Tumor cell division was seen only after extravasation. Tumors tended to develop near microvessels and were often wrapped around them.
Intravital videomicroscopy can provide new information about steps in metastasis. This procedure is applicable to other hosts and can be used in future studies to test hypotheses about molecular mechanisms of tumor spread.
能够直接观察肿瘤转移的技术很少。在实验动物中观察这一过程中各个步骤发生的能力将补充对分子机制的研究。
我们开发了一种使用高分辨率活体视频显微镜的新方法，以直接观察细胞在微循环中停滞、渗出并形成微转移的过程。我们使用该方法研究免疫缺陷鸡胚实验性转移的早期步骤，从而使我们能够在一个相对容易观察的呼吸器官中且在没有宿主免疫反应的情况下开发这项技术。我们的目标是开发适用于该宿主和其他宿主的技术，并阐明该宿主中血行性肿瘤扩散的过程。
我们将荧光标记的B16F1黑色素瘤细胞注入11至13日龄鸡胚的循环系统中，并使用活体视频显微镜随时间观察绒毛尿囊膜中的细胞。
大多数注入的细胞最初被困在绒毛尿囊膜毛细血管丛的孔口或通向该丛的小动脉的逐渐变细的末端。在最初的2小时内，仅在血管腔内发现细胞。8小时后，83%的细胞已经渗出，其余细胞正在渗出过程中。在渗出和肿瘤形成过程中可见细胞形状变化和伪足延伸。仅在渗出后可见肿瘤细胞分裂。肿瘤倾向于在微血管附近形成，并且常常包裹在微血管周围。
活体视频显微镜可以提供有关转移步骤的新信息。该方法适用于其他宿主，可用于未来研究以检验关于肿瘤扩散分子机制的假设。
