New therapeutic agents for chordoma

Chordoma is a rare primary malignant bone sarcoma arising in bones of the base of skull, mobile spine and sacrococcygeum. The tumours are slow-gowing, and present generally late in the course of the disease. In view of their anatomical location and jelly-like nature the tumours are difficult to remove completely. This results in a high incidence of local recurrence which is associated with morbidity, and results in a median survival of seven years. Despite this, the mainstay of treatment is surgery as there is little benefit from conventional chemo-, and or radiotherapy. In 2001, one chordoma cell line had been established. Since then, data on 2 other cell lines have been published, one of which, MUG-Chor1, was created at the Medical University Graz. Professor Flanagan, in collaboration with others, are establishing another two new chordoma cells lines (now at passage 40) (U-CH3 and U-CH7) from patients treated in RNOH. We propose to exploit five chordoma cell lines as models of disease for the purpose of developing new therapies for treatment of this disease. We will achieve this by screening three well-established cell lines against a panel of 365 GlaxoSmithKline protein kinase inhibitors, and another approximately 160 compounds identified as potential therapeutic targets from our previous research. We will perform a single-point screen using a cell viability endpoint assay. The experimental screen will be performed in duplicate using 2 replicates per experiment. Compounds causing a decrease in viability in any cell line of more than 2 standard deviations (CI 95%) compared to DMSO-control samples will be considered to be worth pursuing into an IC50/EC50 screen. Further validation will include a counter-screen in a control cell line, and the hits will also be tested in the two newly established chordoma cell lines (UCH3, UCH7) (vide supra). We plan to validate the mechanism of cell death in the confirmed hits and will perform selectivity testing of promising compounds (e.g. Eurofins Saftey Panel, DiscoveRx). A BioMAP-Profile of the lead compound(s) would allow early identification of off-target effects and allow information to be accrued about drug-related biomarkers/MoA for further investigations. The exploration of mechanisms of drug action, and biomarker discovery will be correlated with next generation sequencing data of the cell lines used in the screen, and tumours from which the cell lines used in the screen derive. This project should allow the identification of potential therapeutic agents which can be taken into additional preclinical studies, and early phase clinical trials.

Chordomas are rare malignant bone tumours which mainly occur along the spinal axis. Although chordomas grow slowly and usually metastasise in advanced stages of disease, they have a poor prognosis because there is hardly any treatment for them. In search for new therapeutic options we screened more than 1000 kinase inhibitors at the University College London (UCL) Cancer Institute in close collaboration with Cancer Research Technology (CRT), a drug discovery institution, and the international pharmaceutical group GlaxoSmithKline (GSK). Based on our promising preclinical data, which have been supported by other laboratories, Chordoma Foundation (which is an internationally active advocacy group for chordoma patients) and associated researchers and clinicians are currently planning a prospective, randomised clinical trial on advanced chordoma. The Cancer Institute is the hub for cancer research at UCL in central London and part of UCLs Faculty of Medical Sciences. I had a research post at the Department of Pathology headed by Professor Adrienne Flanagan, an internationally renowned authority in musculo-skeletal pathology. Her research group focuses on investigating the genetics in close collaboration with the Wellcome Sanger Trust Institute in Cambridge, UK and cell biology of sarcomas, i.e. tumours of bone and soft tissue. In course of this FWF funded project on chordoma we undertook a phenotypic compound screen against 1,097 kinase inhibitors on three well-characterised chordoma cell lines. The vast majority of compounds that displayed chordoma selective growth-inhibitory effects (78%) targeted the epidermal growth factor receptor/erythroblastic leukaemia viral oncogene homolog (EGFR/ERBB) family. Analyses of chemical trends and substituent patterns suggested that EGFR inhibitors with certain chemical structures were more effective against chordoma growth in vitro than other inhibitors. Our most promising EGFR inhibitor significantly reduced tumour growth in two xenograft mouse models. Our findings were consistent with the (p-) EGFR expression reported in the majority of clinical samples. However, we were not able to detect driver mutations in the EGFR signalling pathway or related signalling pathways, which is in line with the published literature on chordoma. Based on the promising preclinical data on EGFR inhibition, Chordoma Foundation and associated researchers and clinicians are currently planning a prospective, randomised clinical trial on advanced chordoma.