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Assessment of Resistance to Tyrosine Kinase Inhibitors by an Interrogation of Signal Transduction Pathways by Antibody Arrays
Published on: September 19, 2018
Differential responses to kinase inhibition in FGFR2-addicted triple negative breast cancer cells: a quantitative
Debbie L Cunningham1, Adil R Sarhan2,3, Andrew J Creese2,4
1School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK. d.cunningham@bham.ac.uk.
Abstract:
Fibroblast Growth Factor (FGF) dependent signalling is frequently activated in cancer by a variety of different mechanisms. However, the downstream signal transduction pathways involved are poorly characterised. Here a quantitative differential phosphoproteomics approach, SILAC, is applied to identify FGF-regulated phosphorylation events in two triple- negative breast tumour cell lines, MFM223 and SUM52, that exhibit amplified expression of FGF receptor 2 (FGFR2) and are dependent on continued FGFR2 signalling for cell viability. Comparative Gene Ontology proteome analysis revealed that SUM52 cells were enriched in proteins associated with cell metabolism and MFM223 cells enriched in proteins associated with cell adhesion and migration. FGFR2 inhibition by SU5402 impacts a significant fraction of the observed phosphoproteome of these cells. This study expands the known landscape of FGF signalling and identifies many new targets for functional investigation. FGF signalling pathways are found to be flexible in architecture as both shared, and divergent, responses to inhibition of FGFR2 kinase activity in the canonical RAF/MAPK/ERK/RSK and PI3K/AKT/PDK/mTOR/S6K pathways are identified. Inhibition of phosphorylation-dependent negative-feedback pathways is observed, defining mechanisms of intrinsic resistance to FGFR2 inhibition. These findings have implications for the therapeutic application of FGFR inhibitors as they identify both common and divergent responses in cells harbouring the same genetic lesion and pathways of drug resistance.
Insights
Fibroblast Growth Factor (FGF) signaling is crucial in triple-negative breast cancer. This study identifies new FGF-regulated targets and reveals flexible pathway architectures, offering insights into FGFR inhibitor resistance mechanisms.
Area of Science:
- Oncology
- Molecular Biology
- Biochemistry
Background:
- Fibroblast Growth Factor (FGF) signaling is frequently activated in cancer via diverse mechanisms.
- Downstream signal transduction pathways of FGF signaling are not fully characterized.
- Triple-negative breast cancer cell lines MFM223 and SUM52 show amplified FGF receptor 2 (FGFR2) expression and depend on FGFR2 signaling for viability.
Purpose of the Study:
- To identify FGF-regulated phosphorylation events in FGFR2-amplified triple-negative breast cancer cells.
- To characterize the downstream signal transduction pathways involved in FGF-dependent cancer.
- To investigate mechanisms of intrinsic resistance to FGFR2 inhibition.
Main Methods:
- Quantitative differential phosphoproteomics using Stable Isotope Labeling by Amino acids in Cell culture (SILAC).
- Comparative Gene Ontology (GO) proteome analysis.
- Inhibition of FGFR2 kinase activity using SU5402.
Main Results:
- Identified numerous FGF-regulated phosphorylation events in MFM223 and SUM52 cells.
- SUM52 cells showed enrichment in cell metabolism proteins, while MFM223 cells were enriched in cell adhesion and migration proteins.
- FGFR2 inhibition impacted a significant fraction of the phosphoproteome, revealing both shared and divergent responses in canonical RAF/MAPK/ERK/RSK and PI3K/AKT/PDK/mTOR/S6K pathways.
- Observed inhibition of phosphorylation-dependent negative-feedback pathways, suggesting mechanisms of intrinsic resistance.
Conclusions:
- This study expands the understanding of FGF signaling in triple-negative breast cancer.
- Identified novel targets for functional investigation within FGF signaling pathways.
- Revealed the flexible architecture of FGF signaling pathways and elucidated mechanisms of intrinsic resistance to FGFR2 inhibition.
- Findings have implications for the therapeutic application of FGFR inhibitors, highlighting common and divergent responses and drug resistance pathways.
