The relevance of using 3D cell cultures, in addition to 2D monolayer cultures, when evaluating breast cancer drug sensitivity and resistance.

Lorraine O’Driscoll,Susan Breslin

doi:10.18632/oncotarget.9935

Abstract

Solid tumours naturally grow in 3D wherein the spatial arrangement of cells affects how they interact with each other. This suggests that 3D cell culture may mimic the natural in vivo setting better than traditional monolayer (2D) cell culture, where cells are grown attached to plastic. Here, using HER2-positive breast cancer cell lines as models (BT474, HCC1954, EFM192A), the effects of culturing cells in 3D using the poly-HEMA method compared to 2D cultures were assessed in terms of cellular viability, response/resistance to anti-cancer drugs, protein expression and enzyme activity. Scanning electron microscopy showed the morphology of cells in 3D to be substantially different to those cultured in 2D. Cell viability in 3D cells was substantially lower than that of cells in 2D cultures, while 3D cultures were more resistant to the effects of HER-targeted (neratinib) and classical chemotherapy (docetaxel) drugs. Expression of proteins involved in cell survival, transporters associated with drug resistance and drug targets were increased in 3D cultures. Finally, activity of drug metabolising enzyme CYP3A4 was substantially increased in 3D compared to 2D cultures. Together this data indicates that the biological information represented by 3D and 2D cell cultures is substantially different i.e. 3D cell cultures demonstrate higher innate resistance to anti-cancer drugs compared to 2D cultures, which may be facilitated by the altered receptor proteins, drug transporters and metabolising enzyme activity. This highlights the importance of considering 3D in addition to 2D culture methods in pre-clinical studies of both newer targeted and more traditional anti-cancer drugs.

Highlights

In the drug development process and, any laboratory setting wishing to mimic as best as possible the in vivo environment in their pre-clinical studies, it is important that the experimental model of the disease being used in testing is as true to life as possible
Ramaiahgari et al [3] found that growing the HepG2 cells in 3D using an extracellular matrix (ECM) hydrogel resulted in restored phenotypic characteristics of hepatocytes as they occur in vivo in terms of proliferation, formation of bile canaliculi, and increased levels of CYP3A4 mRNA and activity; which are, the liver-like properties of the cells
BT474 and HCC1954 cells, when grown in 3D, appear to secrete an extracellular matrix (ECM) [5] which smoothens the surface of the sphere and makes it difficult to distinguish individual cells

Summary

Introduction

In the drug development process and, any laboratory setting wishing to mimic as best as possible the in vivo environment in their pre-clinical studies, it is important that the experimental model of the disease being used in testing is as true to life as possible. The natural manner in which solid tumours grow in vivo is three-dimensional This suggests that growing cancer cells in 3D mimics the in vivo environment better than traditional 2D cell culture due to the ability of the cells to form cell-cell interactions and develop into 3D structures, as opposed to growing flat and attached to cell culture-grade plastic. Ramaiahgari et al [3] found that growing the HepG2 cells in 3D using an ECM hydrogel resulted in restored phenotypic characteristics of hepatocytes as they occur in vivo in terms of proliferation, formation of bile canaliculi, and increased levels of CYP3A4 mRNA and activity; which are, the liver-like properties of the cells Together this data suggests that 3D cell culture is more similar and relevant to the in vivo setting than 2D cell culture

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