Your new predictive tool in oncology drug discovering
There is a significant need for more predictive in vitro efficacy assays in oncology to reduce both the number of costly drug failures in clinical trials and the number of animals used in pre-clinical testing. Performing certain cell-based assays in 3D can improve their relevance as models. Cells grown in a 3D micro-environment have different morphology to those grown in 2D on tissue culture plastic and are in contact with other cells which influences tissue-specific gene expression, cell growth and the uptake and metabolism of drugs. It is known that the tumour physiological environment is intimately connected with cancer growth and progression. The Mimetix® 96-well tissue culture plate provides an ideal architectural environment to support the growth of cells in 3D, i.e. as a tissue rather than a flat layer, in a format that is easy to automate in the laboratory.
Material & Methods
Mimetix scaffolds are created by electrospinning the medical-grade polymer poly(L-lactide) (PLLA) into microfibres, which are highly consistent with regard to fibre diameter and pore size, resulting in excellent reproducibility of cell-based assays.
The scaffold depth of 50 μm is thick enough to provide the benefits of 3D cell morphology, yet thin enough for microscopic imaging.
Over a 10-day culture period, total cell number increased steadily. The measurements were very consistent (CVs of <10%); comparable variability to that seen in 2D experiments (Data from Avanticell Science Ltd.)
Response to apoptotic drugs
HMT3909S8 is known to be resistant to drug-induced apoptosis in 3D hydrogel culture. When grown in Mimetix scaffolds and challenged with 1 μm staurosporine, the cells were significantly more resistant to apoptosis than those grown in 2D.
Response to cytotoxic drugs: Mimetix 3D scaffolds vs. 2D
Cancer cell lines pre-cultured in 3D in the Mimetix scaffold for 21 days show lower sensitivity to two commonly used cytotoxic drugs, carboplatin and tamoxifen, relative to cells pre-cultured for 1 day in conventional 96 well plates. Cells did require some time to adjust to the 3D environment and no difference in drug response was seen between cells grown for 1 day in conventional vs. Mimetix scaffold plates before treatment (data not shown). This indicated that with these drugs there was no significant issue with drug adsorption to the scaffold. The difference in response to drugs may be due to a range of factors related to the 3D micro-environment.
SKOV3 cells show an 8-fold increase in resistance to carboplatin when grown in the Mimetix scaffold (IC50 increases from 60 μM to 500 μM).
HepG2 cells show a 3-fold increase in resistance to tamoxifen when grown in the Mimetix scaffold (IC50 increases from 12 μM to 36 μM).