Three-dimensional in vitro spheroids are a reliable model to study tumor biology and drug toxicity. However, inconsistencies exist in terms of seeding cell density that governs spheroid size and shape, influencing the experimental outcome. We investigated the effect of varying cell densities using glioblastoma cells on tumorsphere formation and their responsiveness to drug treatment. Our results demonstrated that in comparison with spheroids formed with lower cell density, spheroids formed with higher cell density were not only larger in size but also had a larger necrotic core surrounded by a higher number of quiescent cells and were irresponsive to drug treatment. Our study highlights the importance of predetermination of cell density to obtain desired/appropriate spheroid size to produce consistent and reliable data on drug toxicity studies in tumor cells.

中文翻译：

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三维肿瘤球大小对实验结果的关键作用。

三维体外球体是研究肿瘤生物学和药物毒性的可靠模型。然而，在控制球体大小和形状的播种细胞密度方面存在不一致，影响实验结果。我们使用胶质母细胞瘤细胞研究了不同细胞密度对肿瘤球形成及其对药物治疗反应的影响。我们的结果表明，与细胞密度较低的球体相比，细胞密度较高的球体不仅尺寸更大，而且坏死核心更大，周围有更多的静止细胞，对药物治疗无反应。我们的研究强调了预先确定细胞密度以获得所需/合适的球体大小的重要性，以产生关于肿瘤细胞药物毒性研究的一致和可靠的数据。