Receptor tyrosine kinase biomarkers
The present invention relates to the use of receptor tyrosine kinase (RTK) oligomers as markers of RTK activation and signalling. Methods are described based upon determining the presence of RTK oligomers and/or determining the nanometre spatial separation between RTK molecules assembled as RTK oligomers at the cell surface. Such methods are directed to the monitoring of RTK activation in cells and the detection of mutations in RTKs. Methods are also described for determining prognosis for subjects having diseases characterised by aberrant RTK activation and for selecting subjects for treatment with RTK inhibitors.
1. A method of treating a subject comprising
(i) obtaining a sample of cells from a subject,
(ii) detecting the presence of one or more receptor tyrosine kinase (RTK) oligomers in one or more cells in the sample by contacting the one or more cells with a fluorophore-conjugated RTK ligand or a fluorophore-conjugated RTK-specific affibody, and detecting binding between RTK monomers and the fluorophore-conjugated RTK ligand or the fluorophore-conjugated RTK-specific affibody, wherein RTK is EGFR/ErbB1, ErbB2, ErbB3 or ErbB4, and wherein each RTK oligomer comprises more than two RTK monomers,
(iii) determining the nanometre spatial separation between RTK monomers assembled in any of the one or more RTK oligomers,
(iv) identifying the subject as having the nanometre spatial separation between RTK monomers assembled in the one or more RTK oligomers, and
(v) administering to the subject an effective amount of an RTK inhibitor selected from Gefitinib (Iressa), Erlotinib (Tarceva), Lapatinib, Canertinib, Cetuximab (Erbitux) and Panitumumab (Vectibix).
2. The method of claim 1 wherein the subject has been diagnosed with a disease, and wherein the disease is
selected from diabetes, cardiovascular disease including atherosclerosis, inflammatory disorders, bone disorders, neurodegenerative diseases including Alzheimer's disease and motor neurone disease, and arthritis.
3. The method of claim 1 wherein the subject has been diagnosed with a cancer selected from non small-cell lung cancer, small-cell lung cancer, breast cancer, prostate cancer, renal cell cancer, colorectal cancer, glioma, hepatic cancer, melanoma, pancreatic cancer, oesophageal cancer, prostate cancer, ovarian cancer, cervical cancer, lymphoma, leukaemia, head and neck cancer, gastric cancer, endometrial cancer, bladder cancer, squamous and basal cell carcinoma, and bone cancer metastasis.
4. The method of claim 1 wherein the binding between the RTK monomers and the fluorophore-conjugated RTK ligand or the fluorophore-conjugated RTK-specific affibody is detected using a high-resolution imaging method.
5. The method of claim 1 wherein the RTK oligomers are
(a) selected from hexamers, or higher-order oligomers consisting of at least 8, at least 10, at least 12, at least 14, at least 16, at least 18, at least 20 RTK monomers, or
(b) tetramers.
6. The method of claim 1 wherein the binding between the RTK monomers and the fluorophore-conjugated RTK ligand or the fluorophore-conjugated RTK-specific affibody is detected using Fluorophore Localisation Imaging with Photobleaching (FLImP).
7. A method of treating a subject comprising administering an effective amount of a receptor tyrosine kinase (RTK) inhibitor to a subject having RTK activation as determined by
(i) obtaining a sample of cells from a subject; and
(ii) detecting the presence of one or more RTK oligomers in one or more cells in the sample by contacting the one or more cells with a fluorophore-conjugated RTK ligand or a fluorophore-conjugated RTK-specific affibody, and detecting binding between RTK monomers and the fluorophore-conjugated RTK ligand or the fluorophore-conjugated RTK-specific affibody,
wherein each RTK oligomer comprises more than two RTK monomers,
wherein the presence of one or more RTK oligomers is indicative of RTK activation in the one or more cells,
wherein RTK is EGFR/ErbB1, ErbB2, ErbB3 or ErbB4, and
wherein the RTK inhibitor is selected from Gefitinib (Iressa), Erlotinib (Tarceva), Lapatinib, Canertinib, Cetuximab (Erbitux) and Panitumumab (Vectibix).
8. The method of claim 7 wherein the subject has a cancer.
9. The method of claim 1 wherein the one or more cells are contacted with a fluorophore-conjugated RTK ligand, and binding between RTK monomers and the fluorophore-conjugated RTK ligand is detected.
10. The method of claim 9 wherein the RTK is EGFR.
11. The method of claim 9 wherein the binding between RTK monomers and the fluorophore-conjugated RTK ligand is detected using Fluorophore Localisation Imaging with Photobleaching (FLImP).
12. The method of claim 1 wherein the one or more cells are contacted with a fluorophore-conjugated RT-specific affibody, and binding between RTK monomers and the fluorophore-conjugated RTK-specific affibody is detected.
13. The method of claim 12 wherein the RTK is EGFR.
14. The method of claim 12 wherein the binding between RTK monomers and the fluorophore-conjugated RTK-specific affibody is detected using Fluorophore Localisation Imaging with Photobleaching (FLImP).
15. The method of claim 1 wherein the RTK inhibitor is Erlotinib (Tarceva).
16. The method of claim 7 wherein the RTK inhibitor is Erlotinib (Tarceva).
17. The method of claim 1 wherein the RTK oligomers are tetramers.
18. The method of claim 7 wherein the RTK oligomers are tetramers.