This project aims to establish validated in vitro systems for testing the response of cancer stem cells to potential new therapeutics.
Sub-populations of cancer stem cells (CSCs) have important roles in the growth and metastasis of cancers. CSCs can be resistant to chemotherapeutic agents and this is likely to have an impact on tumour recurrence. Developing effective agents is complicated by the discovery that CSC switch between an immobile epithelial phenotype and a motile epithelial-mesenchymal transformation (EMT) phenotype, with each state differing in its drug resistance pattern. Phenotypic switching is influenced by intrinsic cellular factors and the tumour microenvironment.
Tumour transplantation studies in mice are considered the 'gold standard' for characterising CSCs. Around 50 mice are used in a typical xenotransplantation study. Studies are based on the assumption that stem cell survival is too complex to be adequately modelled in vitro. However, basic CSC properties including EMT, are retained even in 2D cultures.
Previous work funded by the NC3Rs has established criteria for the development of 3D co-culture models of fibroblasts with human tumour cells including CSCs, which closely mimic cellular changes observed in vitro. This award will build on this work.
Research details and methods
To replace mouse transplantation assays for studying CSCs, a heterotypic 3D culture system, containing both tumour and stromal cells will be developed, in which in vivo cellular responses (such as invasiveness and altered therapeutic resistance) that are associated with EMT seen are mimicked. The model will be validated by comparison with the cellular heterogeneity observed in tumours and using a reporter system driven by EMT-associated gene expression changes. This will allow rapid analysis of the cellular responses to known inducers and blockers of EMT and provide the basis for a high throughput screen for assessing the efficacy of compounds to control transformation and kill CSCs in their various phenotypic manifestations.
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