title: Comparative analysis of tumor spheroid generation techniques for differential in vitro drug toxicity.
abstract: 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.
authors.affiliation: Department of Materials Science and Engineering, University of Michigan, Ann Arbor, USA.
authors.forename: Shreya
authors.initials: S
authors.lastname: Raghavan
authors.affiliation: Department of Materials Science and Engineering, University of Michigan, Ann Arbor, USA.
authors.forename: Pooja
authors.initials: P
authors.lastname: Mehta
authors.affiliation: Department of Biomedical Engineering, University of Michigan, Ann Arbor, USA.
authors.forename: Eric N
authors.initials: EN
authors.lastname: Horst
authors.affiliation: Department of Materials Science and Engineering, University of Michigan, Ann Arbor, USA.
authors.forename: Maria R
authors.initials: MR
authors.lastname: Ward
authors.affiliation: Department of Biomedical Engineering, University of Michigan, Ann Arbor, USA.
authors.forename: Katelyn R
authors.initials: KR
authors.lastname: Rowley
authors.affiliation: Department of Materials Science and Engineering, University of Michigan, Ann Arbor, USA.|Department of Biomedical Engineering, University of Michigan, Ann Arbor, USA.|Macromolecular Science and Engineering, University of Michigan, Ann Arbor, USA.
authors.forename: Geeta
authors.initials: G
authors.lastname: Mehta
mesh_terms: D018929:Cell Culture Techniques / Q000379:methods*; D045744:Cell Line, Tumor / Q000187:drug effects*; D004354:Drug Screening Assays, Antitumor / Q000379:methods*; D006801:Humans; D018874:Spheroids, Cellular
keywords: breast cancer; high throughput; multicellular tumor spheroids; ovarian cancer; preclinical drug testing