Raghavan Shreya, Mehta Pooja, Horst Eric N, Ward Maria R, Rowley Katelyn R, Mehta Geeta
Department of Materials Science and Engineering, University of Michigan, Ann Arbor, USA.
Department of Biomedical Engineering, University of Michigan, Ann Arbor, USA.
Oncotarget. 2016 Mar 29;7(13):16948-61. doi: 10.18632/oncotarget.7659.
Multicellular tumor spheroids are powerful in vitro models to perform preclinical chemosensitivity assays. We compare different methodologies to generate tumor spheroids in terms of resultant spheroid morphology, cellular arrangement and chemosensitivity. We used two cancer cell lines (MCF7 and OVCAR8) to generate spheroids using i) hanging drop array plates; ii) liquid overlay on ultra-low attachment plates; iii) liquid overlay on ultra-low attachment plates with rotating mixing (nutator plates). Analysis of spheroid morphometry indicated that cellular compaction was increased in spheroids generated on nutator and hanging drop array plates. Collagen staining also indicated higher compaction and remodeling in tumor spheroids on nutator and hanging drop arrays compared to conventional liquid overlay. Consequently, spheroids generated on nutator or hanging drop plates had increased chemoresistance to cisplatin treatment (20-60% viability) compared to spheroids on ultra low attachment plates (10-20% viability). Lastly, we used a mathematical model to demonstrate minimal changes in oxygen and cisplatin diffusion within experimentally generated spheroids. Our results demonstrate that in vitro methods of tumor spheroid generation result in varied cellular arrangement and chemosensitivity.
多细胞肿瘤球体是用于进行临床前化学敏感性测定的强大体外模型。我们从所得球体形态、细胞排列和化学敏感性方面比较了生成肿瘤球体的不同方法。我们使用两种癌细胞系（MCF7和OVCAR8）通过以下方法生成球体：i）悬滴阵列板；ii）在超低附着板上进行液体覆盖；iii）在超低附着板上进行液体覆盖并旋转混合（摇床板）。球体形态测量分析表明，在摇床板和悬滴阵列板上生成的球体中细胞压实度增加。胶原蛋白染色还表明，与传统液体覆盖相比，摇床板和悬滴阵列上的肿瘤球体压实度更高且有重塑现象。因此，与超低附着板上的球体（10 - 20%活力）相比，摇床板或悬滴板上生成的球体对顺铂治疗的化学抗性增加（20 - 60%活力）。最后，我们使用数学模型证明在实验生成的球体中氧气和顺铂扩散的变化最小。我们的结果表明，体外生成肿瘤球体的方法会导致不同的细胞排列和化学敏感性。
