Three-dimensional in vitro culture models in oncology research

Abstract

Cancer is a multifactorial disease that is responsible for 10 million deaths per year. The intra- and inter-heterogeneity of malignant tumors make it difficult to develop single targeted approaches. Similarly, their diversity requires various models to investigate the mechanisms involved in cancer initiation, progression, drug resistance and recurrence. Of the in vitro cell-based models, monolayer adherent (also known as 2D culture) cell cultures have been used for the longest time. However, it appears that they are often less appropriate than the three-dimensional (3D) cell culture approach for mimicking the biological behavior of tumor cells, in particular the mechanisms leading to therapeutic escape and drug resistance. Multicellular tumor spheroids are widely used to study cancers in 3D, and can be generated by a multiplicity of techniques, such as liquid-based and scaffold-based 3D cultures, microfluidics and bioprinting. Organoids are more complex 3D models than multicellular tumor spheroids because they are generated from stem cells isolated from patients and are considered as powerful tools to reproduce the disease development in vitro. The present review provides an overview of the various 3D culture models that have been set up to study cancer development and drug response. The advantages of 3D models compared to 2D cell cultures, the limitations, and the fields of application of these models and their techniques of production are also discussed.

Keywords: 3D cell culture; Bioprinting; Cancer; Liquid-based 3D culture; Microfluidics; Multicellular tumor spheroid; Organoid; Scaffold-based 3D culture.

Fig. 1

Comparison of the publication rate on spheroids and organoids over the past decade. For spheroids, the query used was: [(((Cancer) OR (Neoplasms)) AND ((spheroid) OR (tumorosphere))) NOT (Review)]. For organoids, the query used was: [(((Cancer) OR (Neoplasms)) AND ((organoid) OR (tumoroid))) NOT (Review)]

Fig. 2

Liquid-based 3D cultures. A Liquid overlay; B Hanging drop; C Agitation-based: spinner flask (left), gyratory shaking (middle), rotary cell culture system/rotating wall vessel (right); D Magnetic levitation; E Microcarrier beads

Fig. 3

Liquid overlay technique culture. Osteosarcoma MNNG/HOS (A) and SAOS-2 cells (B), colorectal adenocarcinoma Caco-2 (C), colon cancer HT29 (D), glioblastoma U251 (E) or prostate carcinoma LnCaP (F) cells were seeded into a 96-well low-attachment plates and cultured for 7 days. Scale bar corresponds to 500 µm

Fig. 4

Microfluidic platforms. A Parsortix™ microfluidic platform for isolating circulating tumor cells based on their size and their deformability properties; B Image of PDMS microsystems dedicated to particle separation: spiral microfluidic systems (top); deterministic lateral displacement particle separation system (down). Both are placed on 60 × 22 mm coverslips

Fig. 5

3D culture models for spheroids or tumoroids production. Tumor spheroids are often generated from cell lines, through liquid based-, scaffold based-, microfluidics or bioprinting methods. Depending on the cells added to the model, the tumor spheroid will be mainly composed of cancer cells and other cells and components of the microenvironment can be added. Tumor spheroids often show a round shape. Tumor organoids (or tumoroids) are usually generated from patient tissue samples by using two methods: (i) The submerged culture method that allows the amplification of epithelial cancer stem cells which are then able to produce ECM; (ii) The air–liquid culture method that allows the inclusion of stromal components to the tumoroids. Since tumoroids are self-organizing tissues, they will have a more complex structure than spheroids