Controlled breast cancer microarrays for the deconvolution of cellular multilayering and density effects upon drug responses.
BACKGROUND
Increasing evidence shows that the cancer microenvironment affects both tumorigenesis and the response of cancer to drug treatment. Therefore in vitro models that selectively reflect characteristics of the in vivo environment are greatly needed. Current methods allow us to screen the effect of extrinsic parameters such as matrix composition and to model the complex and three-dimensional (3D) cancer environment. However, 3D models that reflect characteristics of the in vivo environment are typically too complex and do not allow the separation of discrete extrinsic parameters.


RESULTS
In this study we used a poly(ethylene glycol) (PEG) hydrogel-based microwell array to model breast cancer cell behavior in multilayer cell clusters that allows a rigorous control of the environment. The innovative array fabrication enables different matrix proteins to be integrated into the bottom surface of microwells. Thereby, extrinsic parameters including dimensionality, type of matrix coating and the extent of cell-cell adhesion could be independently studied. Our results suggest that cell to matrix interactions and increased cell-cell adhesion, at high cell density, induce independent effects on the response to Taxol in multilayer breast cancer cell clusters. In addition, comparing the levels of apoptosis and proliferation revealed that drug resistance mediated by cell-cell adhesion can be related to altered cell cycle regulation. Conversely, the matrix-dependent response to Taxol did not correlate with proliferation changes suggesting that cell death inhibition may be responsible for this effect.


CONCLUSIONS
The application of the PEG hydrogel platform provided novel insight into the independent role of extrinsic parameters controlling drug response. The presented platform may not only become a useful tool for basic research related to the role of the cancer microenvironment but could also serve as a complementary platform for in vitro drug development.
BioInterface Group, Laboratory for Surface Science and Technology, ETH Zurich, Zurich, Switzerland.
Maria
M
Håkanson
Stefan
S
Kobel
Matthias P
MP
Lutolf
Marcus
M
Textor
Edna
E
Cukierman
Mirren
M
Charnley
D017209:Apoptosis / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D002452:Cell Count; D002453:Cell Cycle / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D016923:Cell Death / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D049109:Cell Proliferation / Q000187:drug effects; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D019008:Drug Resistance, Neoplasm; D005260:Female; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000494:pharmacology; D019012:Integrin beta1 / Q000235:genetics / Q000378:metabolism; D017239:Paclitaxel / Q000494:pharmacology; D011092:Polyethylene Glycols / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D059016:Tumor Microenvironment / Q000187:drug effects* / Q000235:genetics / Q000502:physiology*
D015820:Cadherins; D019012:Integrin beta1; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D011092:Polyethylene Glycols; D017239:Paclitaxel