Optimization of the formation of embedded multicellular spheroids of MCF-7 cells: How to reliably produce a biomimetic 3D model

• Published in: Analytical biochemistry 2016-12, Vol.515, p.47-54
• Main Authors: Zhang, Wenli, Li, Caibin, Baguley, Bruce C., Zhou, Fang, Zhou, Weisai, Shaw, John P., Wang, Zhen, Wu, Zimei, Liu, Jianping
• Format: Article
• Language: English
• Subjects: Biomimetics - methods; Cell Culture Techniques - methods; Cell Survival - drug effects; Collagen gels; Doxorubicin - pharmacology; Female; Hanging drop; Humans; Liquid overlay; MCF-7 Cells; MCF-7 cells; Multicellular spheroids; Spheroids, Cellular - cytology; Spheroids, Cellular - metabolism
• ISSN: 0003-2697; 1096-0309
• DOI: 10.1016/j.ab.2016.10.004

To obtain a multicellular MCF-7 spheroid model to mimic the three-dimensional (3D) of tumors, the microwell liquid overlay (A) and hanging-drop/agar (B) methods were first compared for their technical parameters. Then a method for embedding spheroids within collagen was optimized. For method A, centrifugation assisted cells form irregular aggregates but not spheroids. For method B, an extended sedimentation period of over 24 h for cell suspensions and increased viscosity of the culture medium using methylcellulose were necessary to harvest a dense and regular cell spheroid. When the number was less than 5000 cells/drop, embedded spheroids showed no tight cores and higher viability than the unembedded. However, above 5000 cells/drop, cellular viability of embedded spheroids was not significantly different from unembedded spheroids and cells invading through the collagen were in a sun-burst pattern with tight cores. Propidium Iodide staining indicated that spheroids had necrotic cores. The doxorubicin cytotoxicity demonstrated that spheroids were less susceptible to DOX than their monolayer cells. A reliable and reproducible method for embedding spheroids using the hanging-drop/agarose method within collagen is described herein. The cell culture model can be used to guide experimental manipulation of 3D cell cultures and to evaluate anticancer drug efficacy. The culture procedures of spheroid by the microwell liquid overlay (a) and hanging-drop/agarose (b) methods. When a regular spheroid was harvested, it was embedded into collagen gels for another 72 h culture (c). [Display omitted]