Djordjevic Bozidar, Lange Christopher S
Department of Radiation Oncology, State University of New York, Downstate Medical Center, Brooklyn, New York 11203, USA.
Acta Oncol. 2006;45(4):412-20. doi: 10.1080/02841860500520743.
We have developed a system of mixed aggregates of cultured cells, to model in situ cell interactions. This three-dimensional (3D) system of floating cell aggregates, termed spheroids for their round shape, enables one to monitor their growth in both size and number of constituent clonogens and to measure survival curves for cells having 3D cell-cell interactions. This system was used to measure the three-dimensional cell-cell interactions on growth, and clonogenicity of either AG1522 fibroblasts, or HeLa cervical cancer cells (pure spheroids, or if both feeder and test cells are the same type, pseudohybrid spheroids), and/or of mixtures of both (hybrid spheroids). By following the increase or decrease in size of, or number of clonogens per, spheroid over time, one obtains growth or inhibition curves. By relating these clonogen numbers, one obtains, after a suitable growth period, relative survival. The system allows one to score the effects of irradiation and of other treatments, as well as the effect of interaction of the constituent cells on their survival. Floating pure, or pseudohybrid (composed of 10% live fibroblasts and 90% supralethally irradiated fibroblast feeder cells) spheroids, shrank to about 10-20% of their volume in three days and then remained at that size for up to six days. In contrast, pure spheroids composed of live HeLa cells increased their volume by an order of magnitude over the same period. Survival of cells in spheroids was measured by the ability of individual spheroids to grow beyond a size implying a ten-fold increase. A caveat to be observed is to correct survival for cellular multiplicity, i.e. reduce survival values to compensate for more than one colony former at the time of irradiation. The system of spheroids floating and growing in nutrient medium provides a selective system for evaluating growth of HeLa, and by implication, other neoplastic cells, without interference from (overgrowth by) normal fibroblasts. Thus it is possible to discriminate between normal and neoplastic cells by virtue of whether or not cells grow in suspension. Such a system seems ideal for testing novel strategies (radiation in combination with chemicals), in an in vivo-like environment.
我们开发了一种培养细胞混合聚集体系统，用于模拟原位细胞间相互作用。这种三维（3D）漂浮细胞聚集体系统，因其圆形形状被称为球体，能让人们监测其在大小和组成克隆原数量方面的生长情况，并测量具有3D细胞 - 细胞相互作用的细胞的存活曲线。该系统用于测量AG1522成纤维细胞或HeLa宫颈癌细胞（纯球体，或者如果饲养细胞和测试细胞是同一类型，则为假杂交球体）以及/或者两者混合物（杂交球体）在生长和克隆形成方面的三维细胞 - 细胞相互作用。通过跟踪球体大小的增加或减少，或随时间推移每个球体中克隆原的数量，可获得生长或抑制曲线。通过关联这些克隆原数量，在适当的生长周期后可获得相对存活率。该系统能让人们评估辐射和其他处理的效果，以及组成细胞间相互作用对其存活的影响。漂浮的纯球体或假杂交球体（由10%活的成纤维细胞和90%超致死剂量照射的成纤维细胞饲养细胞组成）在三天内体积缩小至约10% - 20%，然后在长达六天的时间内保持该大小。相比之下，由活的HeLa细胞组成的纯球体在同一时期体积增大了一个数量级。通过单个球体生长超过意味着体积增加十倍的大小的能力来测量球体中细胞的存活率。需要注意的一点是要校正细胞多重性对存活率的影响，即降低存活值以补偿照射时存在多个集落形成细胞的情况。在营养培养基中漂浮并生长的球体系统为评估HeLa以及由此推断的其他肿瘤细胞的生长提供了一个选择性系统，而不受正常成纤维细胞的干扰（过度生长）。因此，凭借细胞是否能在悬浮状态下生长，可以区分正常细胞和肿瘤细胞。这样的系统似乎非常适合在类似体内的环境中测试新策略（辐射与化学物质联合使用）。
