Challenges in spheroid research
Spheroids have gained significant popularity in cancer research because of their more physiological relevance for studying tumor biology compared to traditional two-dimensional cell culture systems. However, several issues are associated with using multicellular spheroids in cancer research.
This article is an overview of the problems associated with spheroids and how it is possible to overcome them for a better research outcome (1,2,3).
1. Heterogeneity: Tumors are genetically unstable with high levels of heterogeneity, which includes differences in genetic mutations, gene expression patterns, and cell behavior. As a result of intratumoral heterogeneity, there is a non-uniform distribution of genetically distinct tumor-cell populations. This heterogeneity or variation is also present in spheroids, making it difficult to study the entire tumor population, resulting in inferior clinical outcomes.
2. Limited penetration: The structure of a spheroid is organized into three main layers: proliferating cells on the outer layer, quiescent cells on the inner layer, and necrotic cells in the spheroid’s core. The core of a multicellular spheroid may be inaccessible to nutrients, oxygen, and drugs due to limited penetration, which can result in hypoxic and necrotic cells in the spheroid’s core. It makes studying drug efficacy and resistance challenging.
3. Reproducibility: Spheroids are composed of complex interactions between cells and the intercellular matrix (ECM) and there are currently standardized protocols for the generation and characterization of multicellular spheroids, which can make it challenging to replicate the experiments and compare results across studies.
Despite these challenges, multicellular spheroids remain a valuable tool for studying cancer biology and evaluating drug efficacy.
To optimize the experiment design and generate more reliable results, BIOFLOATTM by faCellitate is a suitable product. It generates only one spheroid per well which makes it suitable for high throughput screening. The ready-to-use BIOFLOATTM 96 well-plate provides a highly defined and fully inert surface that outperforms existing products by producing uniform and round spheroids allowing data consistency.
1. Mehta G, Hsiao AY, Ingram M, Luker GD, Takayama S. Opportunities and challenges for use of tumor spheroids as models to test drug delivery and efficacy. J Control Release. 2012 Dec 10;164(2):192-204. doi: 10.1016/j.jconrel.2012.04.045. Epub 2012 May 18. PMID: 22613880; PMCID: PMC3436947.
2. Lee KH, Kim TH. Recent Advances in Multicellular Tumor Spheroid Generation for Drug Screening. Biosensors (Basel). 2021 Nov 11;11(11):445. doi: 10.3390/bios11110445. PMID: 34821661; PMCID: PMC8615712.
3. Han SJ, Kwon S, Kim KS. Challenges of applying multicellular tumor spheroids in preclinical phase. Cancer Cell Int. 2021 Mar 4;21(1):152. doi: 10.1186/s12935-021-01853-8. PMID: 33663530; PMCID: PMC7934264