The production of 3D tumor spheroids for cancer drug discovery

Abstract

New cancer drug approval rates are ≤ 5% despite significant investments in cancer research, drug discovery and development. One strategy to improve the rate of success of new cancer drugs transitioning into the clinic would be to more closely align the cellular models used in the early lead discovery with pre-clinical animal models and patient tumors. For solid tumors, this would mandate the development and implementation of three dimensional (3D) in vitro tumor models that more accurately recapitulate human solid tumor architecture and biology. Recent advances in tissue engineering and regenerative medicine have provided new techniques for 3D spheroid generation and a variety of in vitro 3D cancer models are being explored for cancer drug discovery. Although homogeneous assay methods and high content imaging approaches to assess tumor spheroid morphology, growth and viability have been developed, the implementation of 3D models in HTS remains challenging due to reasons that we discuss in this review. Perhaps the biggest obstacle to achieve acceptable HTS assay performance metrics occurs in 3D tumor models that produce spheroids with highly variable morphologies and/or sizes. We highlight two methods that produce uniform size-controlled 3D multicellular tumor spheroids that are compatible with cancer drug research and HTS; tumor spheroids formed in ultra-low attachment microplates, or in polyethylene glycol dimethacrylate hydrogel microwell arrays.

3D cell culture stimulates the secretion of in vivo like extracellular vesicles

“…We observed four classic morphologies presented in the 3D cultured spheroids with peptide hydrogel scaffolds: round, mass, grape, and stella, as shown in Figure 1B, which is consistent with the literature report 53,54 . Confocal fluorescence image was further used to confirm the round tumor-like morphology in Figure 1C, which exhibits the typical in vivo tumor-like tissue architecture 55 with each round cells laid over to form tumor spheroid. Figure 1C is a 3D confocal imaging reconstruction of cervical tumor cell spheroid using our 3D culture method.…”

Potent and Selective Cytotoxic and Anti‐inflammatory Gold(III) Compounds Containing Cyclometalated Phosphine Sulfide Ligands

“…Anticancer activity in 3D multicellular spheroids 3D multicellular tumor spheroids (MCTSs) are used to simulate the in vivo tumor microenvironment and provide higher complexity than the standard 2D monolayer cultures due to their physiological relevance to solid tumors. [26,27] Therefore, to validate the antitumor activity of the synthesized gold complexes in an in vivo tumore nvironment, cervical cancerc ells (HeLa) were grown in ultra-low attachment (ULA) plates for 2days to generate3 Dm ulticellulars pheroids, which weret hen treated with the IC 50 concentrationsoft he gold complexes. Figure 9s hows the morphological changes in the MCTSs after 72 ho ft reatment with the gold complexes.…”

Fabricating large‐scale three‐dimensional constructs with living cells by processing with syringe needles

“…Analysis of these spheroids revealed that the only viable cells existed 200 μm from the surface of construct, while inside the sphere, all cells were dead, presumably due to nutrient and oxygen unavailability. It has been reported that nuclei are undetectable at 150–200 μm from the surface of such constructs due to necrosis . Using the layer‐by‐layer technique, cells located >5 cell layers undergo induced necrosis .…”

“…It has been reported that nuclei are undetectable at 150-200 μm from the surface of such constructs due to necrosis. 25,26 Using the layer-by-layer technique, cells located >5 cell layers undergo induced necrosis. 27 Thus, our results were in agreement with these previous studies.…”