Morris V L, MacDonald I C, Koop S, Schmidt E E, Chambers A F, Groom A C
Department of Microbiology and Immunology, University of Western Ontario, London, Canada.
Clin Exp Metastasis. 1993 Sep;11(5):377-90. doi: 10.1007/BF00132981.
Biomechanical interactions of cancer cells with the microvasculature were studied using high resolution intravital videomicroscopy. We compared initial arrest of murine B16F10 melanoma and D2A1 mammary carcinoma cells fluorescently labelled with calcein-AM, in low pressure (liver) vs high pressure (cremaster muscle) microvascular beds. Cells were arrested due to size restriction at the inflow side of the microcirculation, penetrating further and becoming more deformed in muscle than liver [median length to width ratios of 3.3 vs 1.3 for D2A1 cells, and 2.5 vs 1.2 for B16F10, at 1 min post-injection (p.i.)]. During the next 2 h many cells became stretched, giving maximum length to width ratios of 68 vs 22.1 (D2A1) and 28 vs 5.6 (B16F10) in muscle vs liver. Ethidium bromide exclusion demonstrated that over 97% of the cells maintained membrane integrity for > 2 h p.i. (In contrast, when an acridine orange labelling procedure was used, membrane disruption of B16F10 cells occurred within 15 min p.i.) Our experiments do not indicate the ultimate fate of the cancer cells, but if cell lysis occurs it must be on a time scale of hours rather than minutes. We report a process of 'clasmatosis' in cancer cells arrested in the microcirculation: large membrane-enclosed fragments (> 3 microns in diameter) became 'pinched off' from arrested cells, in both liver and muscle, often within minutes or even seconds of arrest. The significance of this process is not yet understood. In this study intravital videomicroscopy has thus provided a valuable clarification of the interactions of cancer cells with vessel walls during metastasis.
利用高分辨率活体视频显微镜研究了癌细胞与微血管的生物力学相互作用。我们比较了用钙黄绿素-AM荧光标记的小鼠B16F10黑色素瘤细胞和D2A1乳腺癌细胞在低压（肝脏）与高压（提睾肌）微血管床中的初始滞留情况。细胞因在微循环流入侧受到大小限制而滞留，在肌肉中比在肝脏中穿透得更深且变形更严重[注射后1分钟（p.i.），D2A1细胞的长宽比中位数为3.3比1.3，B16F10细胞为2.5比1.2]。在接下来的2小时内，许多细胞被拉长，肌肉与肝脏中D2A1细胞的最大长宽比分别为68比22.1，B16F10细胞为28比5.6。溴化乙锭排除试验表明，超过97%的细胞在注射后>2小时保持膜完整性（相比之下，当使用吖啶橙标记程序时，B16F10细胞在注射后15分钟内发生膜破坏）。我们的实验并未表明癌细胞的最终命运，但如果发生细胞裂解，其时间尺度必定是数小时而非数分钟。我们报告了在微循环中滞留的癌细胞出现“胞质分裂”的过程：在肝脏和肌肉中，直径>3微米的大的膜包裹碎片在细胞滞留后几分钟甚至几秒钟内就从滞留细胞上“掐断”。这一过程的意义尚不清楚。因此，在本研究中，活体视频显微镜为转移过程中癌细胞与血管壁的相互作用提供了有价值的阐释。
