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Cancer Drug Resist 2018;1:266-302 I http://dx.doi.org/10.20517/cdr.2018.18 Page 297

was generated by dosing H2228 and HCC827 xenograft bearing mice with the tyrosine kinase inhibitors,
crizotinib and erlotinib respectively, for prolonged periods of time and subsequently culturing resistant
tumours ex vivo. The cell lines resulting from both these types of model were the object of detailed analysis
such as exome sequencing, RNA-Seq and protein analysis to establish mechanisms of resistance. These cell
lines were subsequently used to test the ability of compounds to overcome resistance both in vitro and in
vivo. In summary, our data exemplify how different techniques can be employed to study drug resistance
in vitro as well as in vivo and to identify novel vulnerabilities in cancer cells caused by different resistance
mechanisms.

56. Modelling stromal/cancer cell invasion as a platform to assess stromal targeted therapy

E P. Carter, A S. Wilson, H M. Kocher, R P. Grose

Centre of Tumour Biology, Barts Cancer Institute, Queen Mary University of London, London EC1M 6BQ,
UK

Cancer cells co-opt their surrounding stroma to facilitate invasion. This is particularly evident in pan-
creatic cancer, which is characterised by a dense stroma largely comprised of activated stellate cells. 3D
modelling presents an excellent method to analyse cancer/stromal interactions and the effects of potential
stroma-targeted therapies. However, many of the current models are time-consuming, low-throughput, and
require extensive processing for analysis. We have developed a fast, semi-high-throughput cancer/stromal
invasion assay that can be used to dissect cancer/stromal interactions and quantitatively assess therapeutic
drug action. Pancreatic cancer cells (Miapaca2) are combined with stellate cells (PS1) in spheroids, which
are subsequently embedded in Matrigel matrix on glass in a 96 well plate format. Over 48 h dramatic cell
invasion is observed from the central spheroid, with stellate cells leading the collective invasion of cancer
cells. This is apparent from the confocal imaging of stellate and cancer cell markers, plus the use of fluo-
rescently labelled cells. Measurement of the invasive area serves as a rapid quantitative readout. Fibroblast
growth factor receptor 1 (FGFR1) activity in stellate cells has been reported to influence cancer cell inva-
sion, and indeed, treatment with the FGFR inhibitor AZD4547 reduces invasion in a concentration-de-
pendent manner. Thus, this model provides a fast, semi-high-throughput system to interrogate molecular
crosstalk during cancer cell invasion and objectively interrogate both mechanism and efficacy of stromal-
targeted therapies.

57. Chemosensitivity associated chromatin conformation changes influence genomic
cisplatin-adduct distribution

2
1
1
1
John Gallon , Erick Loomis , Nicholas Martin , James Flanagan , Robert Brown 1
1 Department of Surgery and Cancer, Imperial College London, London, UK
2 Trace Element Laboratory, Clinical Biochemistry, Charing Cross Hospital

Changes in chromatin organization are associated with sensitivity/resistance to DNA damaging, anti-
cancer drugs, such as cisplatin; widely used in the treatment of ovarian cancer. However, how chromatin
conformation changes during the acquisition of resistance and how this influences cisplatin-DNA adduct
formation are poorly understood. We investigated platinum-adduct distribution in the context of chroma-
tin accessibility in three pairs of cisplatin sensitive and resistant ovarian cancer cell lines, including lines
isolated from high-grade serous ovarian cancer patients following chemotherapy (PEO1-PEO4). Using
ATAC-seq we show chromatin accessibility changes distinguishing resistant ovarian cell lines from their
sensitive counterparts, with regions of differentially accessible (DA) chromatin primarily at intergenic