Effects of the Physical Microenvironment on Endometrial Cancer Cells (Ishikawa)
Tan, Li Hui
With the realization that mechanical signals are important in controlling cancer cell behaviours, a new in vitro model has been developed to incorporate physical signals in laboratory studies. Here, we developed a system to fabricate hard polymers with imprinted cell topography, which we called a Bioimprint, and then we used the Bioimprint as the platform to culture endometrial cancer cells on. With Bioimprint high resolution of cell replicas were produced with cell-like features that retain all the micro- and nanoscale details of the cells. This enabled us, importantly, to study the effect of surface physical topography on endometrial cancer cell behaviours. The physical topography we used here was the cell-like topography that the cells encounter in real cell microenvironments. We fabricated the Bioimprint of cells onto polymethacrylate (pMA) and compared the cells cultured on it to the cells on flat pMA. pMA is not a common cell culture material, therefore, we compared cell culture on pMA with the conventional cell culture materials: glass and polystyrene (pST). We then fabricated the Bioimprint onto pST, and compared the response of cells cultured on the replica with that cultured on the flat pST. Moreover, on pST, the Bioimprint was made in two forms: pit-like (negative) versus hump-like (positive) topographies, which enabled us to further investigate the effect of distinct topographies on cell behaviours. We also extended our study on flat and pST Bioimprints to study the effect of culture serum, fetal bovine serum (FBS), on cell responses to surface physical topography. In this report, we characterized the behaviours of endometrial cancer cells and studied the biological changes in response to culture substrate materials and culture substrate with cell-like topography. We examined cell adhesion, morphology, spreading, expression of adhesion molecules and growth. The studies of pST Bioimprints were extended to examine the cell protein profile, and cell responses to anticancer agents, in serum-supplemented or serum-free culture media. The comparison between glass, tissue culture grade pST and pMA showed that substrate material modulated cell behaviours. Additionally, imprinting with cell-like topography also altered cell behaviours. Here, we showed that Ishikawa endometrial cancer cells spread wider and grew faster on glass and pST compared to pMA. Further, on the pMA surface that was imprinted with cell-like topography, the cells spread and grew better compared to cells on flat pMA. On the other hand, when pST, which is a favourable cell culture surface, was imprinted with the cell-like topography, the topographical effect was to restrict cell spreading and growth. Most importantly, the change in cell growth behaviour was modulated through different proliferation biomolecules on each of these pMA and pST Bioimprints, indicating again the interaction of chemical and physical topography in regulating cell behaviours. In addition, the comparison between pST hump-like versus the pit-like topographies showed that the cells on the hump-like topography showed a greater response of an alteration of cell growth, expression of adhesion molecules when compared to cells on flat substrate. Furthermore, relative to cells on (f)pST proteomics analysis similarly showed that cells on hump-like topography had more alteration in protein expression than cells on pit-like topography. Most of these identified proteins were involved in cell energy homeostasis, growth and structural modulation. Additionally, the extended studies with culture serum without FBS again showed that endometrial cancer cells responded to physical topography. The cell responses were different from those in culture medium supplemented with FBS. This again indicated that the topographical influences on cells were in turn affected by chemical factors (the biological source of serum chemical factors). Notably, cell culture in serum free medium similarly showed a greater tropographical response to the hump-like topography compared to cells on a flat substrate. Here, we reveal the potential of targeting cell mechano-signalling as cancer treatment, and also this project describes a culture platform that inherently incorporates physical signals in laboratory cell culture studies. This is the first report that showed that Ishikawa endometrial cancer cells respond to the culture substrate material and cell-like physical topography.
Advisor: Evans, John J.; Alkaisi, Maan M.; Sykes, Peter H.
Degree Name: Doctor of Philosophy
Degree Discipline: Obstetrics and Gynecology
Publisher: University of Otago
Keywords: Endometrial; Cancer; Physical; Microenvironment; Topography; Substrate-material; Surface-chemistry; Mechanical; Force; Mechano-signalling; Morphology; Spreading; Growth; Adhesion; Actin-filaments; Integrins; Focal-adhesion-kinase; Anticancer-agents; Chemotherapy-drugs; VEGF; FBS; iTRAQ-proteomics
Research Type: Thesis