The advent of different methods for 3-dimensional (3D) cell culture has allowed scientists to address some of the limitations of conventional methods. 3D cell culture systems attempt to mimic the in vivo tumour microenvironment accurately allowing more physiological studies of cancer cell response to treatment. A major component of the tumour microenvironment which has been overlooked during past years of drug discovery and cancer studies is the interstitial fluid pressure (IFP). The aim of this project is to develop novel methods for studying breast cancer cell behaviour in terms of invasion and drug responses in a more physiologically relevant environment.
The MDA-MB231 breast cancer cell line presents characteristics of the triple negative breast cancer subtype. In the 3D system MDA-MB231 cells were seeded in a dense 80 mg/ml collagen scaffold surrounded by stromal collagen to form an artificial cancer mass (ACM) enabling the invasive properties of cancer cells to be studied. The morphology/metabolic activity of the cells in 2D, 3D, static and dynamic conditions were evaluated using an Alamar Blue assay and confocal microscopy.
The cells showed lower metabolic activity in 3D compared to 2D. Whereas, so far, gene expression levels for epidermal mesenchymal (EMT) markers has demonstrated that the dynamic environment results in altered expression of snail, vimentin and cadherin but does not appear to affect MMP14 which is involved in collagen type I degradation. Furthermore, the initial results, showed that cell grown in 3D ACM which were exposed to ECM (collagen) produced more vimentin protein than the cells cultured as 2D monolayers .
The results obtained in this study have shown that the proliferation rate and drug responsiveness of cancer cell lines varies according to the different microenvironments in which the cells are cultured. Applying flow and the implementation of IFP affects the expression levels of EMT related markers. The next step will be to evaluate this further in the context of protein expression levels and cellular invasion.