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Page 300 Cancer Drug Resist 2018;1:266-302 I http://dx.doi.org/10.20517/cdr.2018.18

integrated analysis of tumour composition and genomics across a wide spectrum of solid cancers profiled
by The Cancer Genome Atlas Project. Initially studying head and neck squamous cell carcinoma, we iden-
tify two distinct tumour subgroups: “immune hot” and “immune cold”, which display differing mutation
burden, cytokine signalling, cytolytic activity, and oncogenic driver events. We demonstrate the existence
of such tumour subgroups across 18 further solid cancer types and, using gene expression data from recent
clinical trials, show that transcriptional signatures of hot tumours are selectively engaged in melanomas
that respond to immune checkpoint blockade. Finally, we show that treatment-naive hot tumours are
markedly enriched for known immune-resistance genomic alterations, potentially explaining the heteroge-
neity of immunotherapy response and prognosis seen within this group. Finally, our genomic copy number
analysis revealed potential targets for “warming-up” cold tumours, including epidermal growth factor re-
ceptor signalling.

62. Quantitative live imaging of Ponatinib in vitro enabled by stimulated Raman scattering
microscopy

2
1,2
Kristel Sepp , Martin Lee , Valerie G. Brunton , Alison N. Hulme 1
2
1 EaStCHEM School of Chemistry, The University of Edinburgh, Joseph Black Building, David Brewster Road,
Edinburgh EH9 3FJ, UK
2 Edinburgh Cancer Research Centre, Institute of Genetics and Molecular Medicine, The University of Edin-
burgh, Crewe Road South, Edinburgh EH4 2XR, UK

Ponatinib, a clinically approved tyrosine kinase inhibitor used to treat chronic myeloid leukemia (CML),
has an alkyne moiety in its structure that makes it inherently Raman active in the cellular silent region of
the Raman spectrum. Stimulated Raman Scattering (SRS) microscopy is a quantitative imaging tool that
allows spatial and temporal measurements and discrete intracellular registration by combining with fluo-
rescent reporters. In addition, SRS allows quantitative measurements of intracellular drug concentrations.
This has enabled utilisation of SRS microscopy to image label-free ponatinib with high sensitivity and spec-
ificity in a number of live human CML cell lines. Drug resistance is a widespread problem in CML treat-
ment, where ponatinib resistant patients have very limited treatment options. To better understand pona-
tinib resistance mechanisms, a human CML cell line with acquired ponatinib resistance was developed.
Ponatinib concentration in parental and ponatinib resistant CML cells was determined and the values
were found to be comparable to those obtained by quantitative LC-MS. It was found that lysosomal trap-
ping causes a 730-fold increase in drug concentration inside the cell. These studies also provide evidence
that ponatinib accumulation in lysosomes is a potential CML resistance mechanism, as the intralysosomal
concentration was increased 1.9-fold in the ponatinib resistant cell line. It was further demonstrated that
treatment with chloroquine to increase lysosomal pH, reduces the lysosomal concentration of ponatinib by
2-fold and 2.6-fold in parental and ponatinib resistant cells respectively. This preliminary data suggest that
chloroquine combination treatment could be useful in ponatinib resistant CML.

63. Resistance to chemotherapy used for early and advanced settings in patients diagnosed
with triple negative breast cancer - the Kent cancer network experience

Vasileios Angelis, Emily Parsons, Claire Ryan, Catherine Harper-Wynne

Kent Cancer Network, Maidstone and Tunbridge Wells NHS Trust, Hermitage Lane, Maidstone, Kent ME16
9QQ, UK